Sequential Combination of Electro-Fenton and Electrochemical Chlorination Processes for the Treatment of Anaerobically-Digested Food Wastewater.

PubMed

Shin, Yong-Uk; Yoo, Ha-Young; Kim, Seonghun; Chung, Kyung-Mi; Park, Yong-Gyun; Hwang, Kwang-Hyun; Hong, Seok Won; Park, Hyunwoong; Cho, Kangwoo; Lee, Jaesang

2017-09-19

A two-stage sequential electro-Fenton (E-Fenton) oxidation followed by electrochemical chlorination (EC) was demonstrated to concomitantly treat high concentrations of organic carbon and ammonium nitrogen (NH 4 + -N) in real anaerobically digested food wastewater (ADFW). The anodic Fenton process caused the rapid mineralization of phenol as a model substrate through the production of hydroxyl radical as the main oxidant. The electrochemical oxidation of NH 4 + by a dimensionally stable anode (DSA) resulted in temporal concentration profiles of combined and free chlorine species that were analogous to those during the conventional breakpoint chlorination of NH 4 + . Together with the minimal production of nitrate, this confirmed that the conversion of NH 4 + to nitrogen gas was electrochemically achievable. The monitoring of treatment performance with varying key parameters (e.g., current density, H 2 O 2 feeding rate, pH, NaCl loading, and DSA type) led to the optimization of two component systems. The comparative evaluation of two sequentially combined systems (i.e., the E-Fenton-EC system versus the EC-E-Fenton system) using the mixture of phenol and NH 4 + under the predetermined optimal conditions suggested the superiority of the E-Fenton-EC system in terms of treatment efficiency and energy consumption. Finally, the sequential E-Fenton-EC process effectively mineralized organic carbon and decomposed NH 4 + -N in the real ADFW without external supply of NaCl.

Degradation alternatives for a commercial fungicide in water: biological, photo-Fenton, and coupled biological photo-Fenton processes.

PubMed

López-Loveira, Elsa; Ariganello, Federico; Medina, María Sara; Centrón, Daniela; Candal, Roberto; Curutchet, Gustavo

2017-11-01

Imazalil (IMZ) is a widely used fungicide for the post-harvest treatment of citrus, classified as "likely to be carcinogenic in humans" for EPA, that can be only partially removed by conventional biological treatment. Consequently, specific or combined processes should be applied to prevent its release to the environment. Biological treatment with adapted microorganism consortium, photo-Fenton, and coupled biological photo-Fenton processes were tested as alternatives for the purification of water containing high concentration of the fungicide and the coadjutants present in the commercial formulation. IMZ-resistant consortium with the capacity to degrade IMZ in the presence of a C-rich co-substrate was isolated from sludge coming from a fruit packaging company wastewater treatment plant. This consortium was adapted to resist and degrade the organics present in photo-Fenton-oxidized IMZ water solution. Bacteria colonies from the consortia were isolated and identified. The effect of H 2 O 2 initial concentration and dosage on IMZ degradation rate, average oxidation state (AOS), organic acid concentration, oxidation, and mineralization percentage after photo-Fenton process was determined. The application of biological treatment to the oxidized solutions notably decreased the total organic carbon (TOC) in solution. The effect of the oxidation degree, limited by H 2 O 2 concentration and dosage, on the percentage of mineralization obtained after the biological treatment was determined and explained in terms of changes in AOS. The concentration of H 2 O 2 necessary to eliminate IMZ by photo-Fenton and to reduce TOC and chemical oxygen demand (COD) by biological treatment, in order to allow the release of the effluents to rivers with different flows, was estimated.

Treatment of landfill leachate by the Fenton process.

PubMed

Deng, Yang; Englehardt, James D

2006-12-01

In recent years, studies of leachate treatment by conventional Fenton, photo-Fenton and electro-Fenton processes have indicated that these methods can effectively reduce concentrations of organic contaminants and color. In addition, the process can increase the biodegradable fraction of organic constituents in leachate, particularly in mature or biologically recalcitrant leachate. Oxidation and coagulation both play important roles in the removal of organics. Initial pH, dosages of Fenton reagents, aeration, final pH, reagent addition mode, temperature, and UV irradiation may influence final treatment efficiency. In this paper, current knowledge of performance and economics of Fenton processes for treatment of landfill leachate as reported for laboratory, pilot and full-scale studies is reviewed, with the conclusion that the Fenton process is an important and competitive technology for the treatment or pretreatment of landfill leachate.

Determination of the acute toxicities of physicochemical pretreatment and advanced oxidation processes applied to dairy effluents on activated sludge.

PubMed

Sivrioğlu, Özge; Yonar, Taner

2015-04-01

In this study, the acute toxicities of raw, physicochemical pre-treated, ozonated, and Fenton reagent applied samples of dairy wastewater toward activated sludge microorganisms, evaluated using the International Organization for Standardization's respiration inhibition test (ISO 8192), are presented. Five-day biological oxygen demand (BOD5) was measured to determine the biodegradability of physicochemical treatment, ozonation, Fenton oxidation or no treatment (raw samples) of dairy wastewater. Chemical pretreatment positively affected biodegradability, and the inhibition exhibited by activated sludge was removed to a considerable degree. Ozonation and the Fenton process exhibited good chemical oxygen demand removal (61%) and removal of toxins. Low sludge production was observed for the Fenton process applied to dairy effluents. We did not determine the inhibitory effect of the Fenton-process on the activated sludge mixture. The pollutant-removal efficiencies of the applied processes and their associated operating costs were determined. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Heterocatalytic Fenton oxidation process for the treatment of tannery effluent: kinetic and thermodynamic studies.

PubMed

Karthikeyan, S; Ezhil Priya, M; Boopathy, R; Velan, M; Mandal, A B; Sekaran, G

2012-06-01

BACKGROUND, AIM, SCOPE: Treatment of wastewater has become significant with the declining water resources. The presence of recalcitrant organics is the major issue in meeting the pollution control board norms in India. The theme of the present investigation was on partial or complete removal of pollutants or their transformation into less toxic and more biodegradable products by heterogeneous Fenton oxidation process using mesoporous activated carbon (MAC) as the catalyst. Ferrous sulfate (FeSO(4)·7H(2)O), sulfuric acid (36 N, specific gravity 1.81, 98% purity), hydrogen peroxide (50% v/v) and all other chemicals used in this study were of analytical grade (Merck). Two reactors, each of height 50 cm and diameter 6 cm, were fabricated with PVC while one reactor was packed with MAC of mass 150 g and other without MAC served as control. The oxidation process was presented with kinetic and thermodynamic constants for the removal of COD, BOD, and TOC from the wastewater. The activation energy (Ea) for homogeneous and heterogeneous Fenton oxidation processes were 44.79 and 25.89 kJ/mol, respectively. The thermodynamic parameters ΔG, ΔH, and ΔS were calculated for the oxidation processes using Van't Hoff equation. Furthermore, the degradation of organics was confirmed through FTIR and UV-visible spectroscopy, and cyclic voltammetry. The heterocatalytic Fenton oxidation process efficiently increased the biodegradability index (BOD/COD) of the tannery effluent. The optimized conditions for the heterocatalytic Fenton oxidation of organics in tannery effluent were pH 3.5, reaction time-4 h, and H(2)O(2)/FeSO(4)·7H(2)O in the molar ratio of 2:1.

FENTON-DRIVEN CHEMICAL REGENERATION OF MTBE-SPENT GAC

EPA Science Inventory

Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was chemically regenerated utilizing the Fenton mechanism. Two successive GAC regeneration cycles were performed involving iterative adsorption and oxidation processes: MTBE was adsorbed to the GAC, oxidized, r...

Chemical oxidation for mitigation of UV-quenching substances (UVQS) from municipal landfill leachate: Fenton process versus ozonation.

PubMed

Jung, Chanil; Deng, Yang; Zhao, Renzun; Torrens, Kevin

2017-01-01

UV-quenching substance (UVQS), as an emerging municipal solid waste (MSW)-derived leachate contaminant, has a potential to interfere with UV disinfection when leachate is disposed of at publicly owned treatment works (POTWs). The objective of this study was to evaluate and compare two chemical oxidation processes under different operational conditions, i.e. Fenton process and ozonation, for alleviation of UV 254 absorbance of a biologically pre-treated landfill leachate. Results showed that leachate UV 254 absorbance was reduced due to the UVQS decomposition by hydroxyl radicals (·OH) during Fenton treatment, or by ozone (O 3 ) and ·OH during ozonation. Fenton process exhibited a better treatment performance than ozonation under their respective optimal conditions, because ·OH could effectively decompose both hydrophobic and hydrophilic dissolved organic matter (DOM), but O 3 tended to selectively oxidize hydrophobic compounds alone. Different analytical techniques, including molecular weight (MW) fractionation, hydrophobic/hydrophilic isolation, UV spectra scanning, parallel factor (PARAFAC) analysis, and fluorescence excitation-emission matrix spectrophotometry, were used to characterize UVQS. After either oxidation treatment, residual UVQS was more hydrophilic with a higher fraction of low MW molecules. It should be noted that the removed UV 254 absorbance (ΔUV 254 ) was directly proportional to the removed COD (ΔCOD) for the both treatments (Fenton process: ΔUV 254  = 0.011ΔCOD; ozonation: ΔUV 254  = 0.016ΔCOD). A greater ΔUV 254 /ΔCOD was observed for ozonation, suggesting that oxidant was more efficiently utilized during ozonation than in Fenton treatment for mitigation of the UV absorbance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fenton-like initiation of a toluene transformation mechanism

EPA Science Inventory

In Fenton-driven oxidation treatment systems, reaction intermediates derived from parent compounds can play a significant role in the overall treatment process. Fenton-like reactions in the presence of toluene or benzene, involved a transformation mechanism that was highly effici...

Removal of pharmaceuticals from water by homo/heterogonous Fenton-type processes - A review.

PubMed

Mirzaei, Amir; Chen, Zhi; Haghighat, Fariborz; Yerushalmi, Laleh

2017-05-01

The presence of emerging contaminants such as pharmaceuticals in natural waters has raised increasing concern due to their frequent appearance and persistence in the aquatic ecosystem and the threat to health and safety of aquatic life, even at trace concentrations. Conventional water treatment processes are known to be generally inadequate for the elimination of these persistent contaminants. Therefore, the use of advanced oxidation processes (AOPs) which are able to efficiently oxidize organic pollutants has attracted a great amount of attention. The main limitation of AOPs lies in their high operating costs associated with the consumption of energy and chemicals. Fenton-based processes, which utilize nontoxic and common reagents and potentially can exploit solar energy, will considerably reduce the removal cost of recalcitrant contaminants. The disadvantages of homogeneous Fenton processes, such as the generation of high amounts of iron-containing sludge and limited operational range of pH, have prompted much attention to the use of heterogeneous Fenton processes. In this review, the impacts of some controlling parameters including the H 2 O 2 and catalyst dosage, solution pH, initial contaminants concentrations, temperature, type of catalyst, intensity of irradiation, reaction time and feeding mode on the removal efficiencies of hetero/homogeneous Fenton processes are discussed. In addition, the combination of Fenton-type processes with biological systems as the pre/post treatment stages in pilot-scale operations is considered. The reported experimental results obtained by using Fenton and photo-Fenton processes for the elimination of pharmaceutical contaminants are also compiled and evaluated. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ferrous ions reused as catalysts in Fenton-like reactions for remediation of agro-food industrial wastewater.

PubMed

Leifeld, Vanessa; Dos Santos, Tâmisa Pires Machado; Zelinski, Danielle Wisniewski; Igarashi-Mafra, Luciana

2018-09-15

Cassava is the most important tuberous root in tropical and subtropical regions of the world, being the third largest source of carbohydrates. The root processing is related to the production of starch, an important industrial input, which releases a highly toxic liquid wastewater due to its complex composition, which inhibits high performances of conventional effluent treatments. This study aims to evaluate Fenton-like and photo-Fenton-like reactions for treatment of cassava wastewater, reusing ferrous ions from the preliminary coagulation stage. Pre-treated cassava wastewater was submitted to oxidation in three variations of hydrogen peroxide concentrations, with more relevant analytical responses verified in color, turbidity, COD (Chemical Oxygen Demand), and acute toxicity in Artemia salina, besides the action of radicals during Fenton-like reactions. At higher peroxide concentrations, a decrease of 68% in turbidity and 70% in COD on the photo-Fenton-like system was observed, even at slow reaction rates (fastest rate constant k = 2 × 10 -4 min -1 ). Inclusion of UV increases the viability of the Fenton-like reactions by supplementing the reaction medium with hydroxyl radicals, verified by the tert-butanol tests. The oxidation process leads to high EC 50 values in 24 h of incubation in Fenton-like reactions and 48 h in photo-Fenton-like reactions. Final COD and turbidity suggests that the reuse of iron, which remains in the preliminary treatment step shows a great potential as a catalyst for Fenton-like advanced oxidation processes. Tertiary treatment can be less expensive and harmful to the environment, reducing production of residual sludge and metal content in the final effluent, which reduces polluting potential of the effluent regarding solid waste. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparison of Nitrilotriacetic Acid and [S,S]-Ethylenediamine-N,N'-disuccinic Acid in UV-Fenton for the Treatment of Oil Sands Process-Affected Water at Natural pH.

PubMed

Zhang, Ying; Klamerth, Nikolaus; Chelme-Ayala, Pamela; Gamal El-Din, Mohamed

2016-10-04

The application of UV-Fenton processes with two chelating agents, nitrilotriacetic acid (NTA) and [S,S]-ethylenediamine-N,N'-disuccinic acid ([S,S]-EDDS), for the treatment of oil sands process-affected water (OSPW) at natural pH was investigated. The half-wave potentials of Fe(III/II)NTA and Fe(III/II)EDDS and the UV photolysis of the complexes in Milli-Q water and OSPW were compared. Under optimum conditions, UV-NTA-Fenton exhibited higher efficiency than UV-EDDS-Fenton in the removal of acid extractable organic fraction (66.8% for the former and 50.0% for the latter) and aromatics (93.5% for the former and 74.2% for the latter). Naphthenic acids (NAs) removals in the UV-NTA-Fenton process (98.4%, 86.0%, and 81.0% for classical NAs, NAs + O (oxidized NAs with one additional oxygen atom), and NAs + 2O (oxidized NAs with two additional oxygen atoms), respectively) under the experimental conditions were much higher than those in the UV-H 2 O 2 (88.9%, 48.7%, and 54.6%, correspondingly) and NTA-Fenton (69.6%, 35.3%, and 44.2%, correspondingly) processes. Both UV-NTA-Fenton and UV-EDDS-Fenton processes presented promoting effect on the acute toxicity of OSPW toward Vibrio fischeri. No significant change of the NTA toxicity occurred during the photolysis of Fe(III)NTA; however, the acute toxicity of EDDS increased as the photolysis of Fe(III)EDDS proceeded. NTA is a much better agent than EDDS for the application of UV-Fenton process in the treatment of OSPW.

Evaluation of the biodegradability and toxicity of landfill leachates after pretreatment using advanced oxidative processes.

PubMed

da Costa, Fabio Moraes; Daflon, Sarah Dario Alves; Bila, Daniele Maia; da Fonseca, Fabiana Valeria; Campos, Juacyara Carbonelli

2018-06-01

Leachate from urban solid waste landfills is a complex mixture of organic and inorganic substances that cause damage to the environment, due to the high concentration of recalcitrant organic matter and toxicity. The objective of this study was to apply advanced oxidation processes (AOP), namely the dark Fenton and solar photo-Fenton processes, to young and old landfill leachates prior to biological treatment. The leachates were obtained from the Seropedica and Gramacho landfill sites, respectively, located in Rio de Janeiro State, Brazil. For the two Fenton processes, different conditions of pH (1.5, 3.0 and 5.0) and Fe 2+ : H 2 O 2 ratio (1:2, 1:5 and 1:10) were evaluated. Biodegradability was evaluated using the Zahn-Wellens methodology and Aliivibrio fischeri acute toxicity tests were conducted in order to predict the toxicity in the activated sludge. The best conditions for both Fenton processes were pH of 3.0 and Fe 2+ : H 2 O 2 and COD RAW :H 2 O 2 mass ratios of 1:5 and 1:1, respectively. The solar photo-Fenton process was more effective at improving the quality for both leachates, reaching COD, TOC and abs 254 nm reductions of 82%, 85% and 96.3%, respectively, for the Seropedica landfill leachate. In the case of the Gramacho landfill leachate, the corresponding reductions were 78.2, 80.7% and 91.1%, respectively. The biodegradability results for the untreated leachates from the Seropedica and Gramacho sites were 65% and 30% respectively. The biodegradability of both leachates was improved by the Fenton processes, especially the solar photo-Fenton process, which increased the leachate biodegradability to 89% (Seropedica) and 69% (Gramacho). For both leachates, a greater reduction in the acute toxicity was achieved with the solar photo-Fenton compared to the dark-Fenton process. The Seropedica landfill leachate showed high toxicity (EC50 = 33%, 15 min), after the dark Fenton and solar photo Fenton processes, with EC50 values of 81 and 91%, respectively. In the case of Gramacho landfill leachate toxicity, the EC50 value of the raw leachate was 13%, whereas after the dark Fenton and solar photo Fenton processes the corresponding values were 54% and 59%, respectively. These results indicate that the Fenton process (especially solar photo-Fenton), was efficient in terms of increasing the biodegradability and reducing the toxicity of the leachate. This is important in relation to protecting the microbiological community in the activated sludge process. Copyright © 2018 Elsevier Ltd. All rights reserved.

Degradation of dyes from aqueous solution by Fenton processes: a review.

PubMed

Nidheesh, Puthiya Veetil; Gandhimathi, Rajan; Ramesh, Srikrishnaperumal Thanga

2013-04-01

Several industries are using dyes as coloring agents. The effluents from these industries are increasingly becoming an environmental problem. The removal of dyes from aqueous solution has a great potential in the field of environmental engineering. This paper reviews the classification, characteristics, and problems of dyes in detail. Advantages and disadvantages of different methods used for dye removal are also analyzed. Among these methods, Fenton process-based advanced oxidation processes are an emerging prospect in the field of dye removal. Fenton processes have been classified and represented as "Fenton circle". This paper analyzes the recent studies on Fenton processes. The studies include analyzing different configurations of reactors used for dye removal, its efficiency, and the effects of various operating parameters such as pH, catalyst concentration, H2O2 concentration, initial dye concentration, and temperature of Fenton processes. From the present study, it can be conclude that Fenton processes are very effective and environmentally friendly methods for dye removal.

Degradation of 2,4-dinitrophenol using a combination of hydrodynamic cavitation, chemical and advanced oxidation processes.

PubMed

Bagal, Manisha V; Gogate, Parag R

2013-09-01

In the present work, degradation of 2,4-dinitrophenol (DNP), a persistent organic contaminant with high toxicity and very low biodegradability has been investigated using combination of hydrodynamic cavitation (HC) and chemical/advanced oxidation. The cavitating conditions have been generated using orifice plate as a cavitating device. Initially, the optimization of basic operating parameters have been done by performing experiments over varying inlet pressure (over the range of 3-6 bar), temperature (30 °C, 35 °C and 40 °C) and solution pH (over the range of 3-11). Subsequently, combined treatment strategies have been investigated for process intensification of the degradation process. The effect of HC combined with chemical oxidation processes such as hydrogen peroxide (HC/H2O2), ferrous activated persulfate (HC/Na2S2O8/FeSO4) and HC coupled with advanced oxidation processes such as conventional Fenton (HC/FeSO4/H2O2), advanced Fenton (HC/Fe/H2O2) and Fenton-like process (HC/CuO/H2O2) on the extent of degradation of DNP have also been investigated at optimized conditions of pH 4, temperature of 35 °C and inlet pressure of 4 bar. Kinetic study revealed that degradation of DNP fitted first order kinetics for all the approaches under investigation. Complete degradation with maximum rate of DNP degradation has been observed for the combined HC/Fenton process. The energy consumption analysis for hydrodynamic cavitation based process has been done on the basis of cavitational yield. Degradation intermediates have also been identified and quantified in the current work. The synergistic index calculated for all the combined processes indicates HC/Fenton process is more feasible than the combination of HC with other Fenton like processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Selective Fenton-like oxidation of methylene blue on modified Fe-zeolites prepared via molecular imprinting technique.

PubMed

Zhang, Yuanyuan; Shang, Jiaobo; Song, Yanqun; Rong, Chuan; Wang, Yinghui; Huang, Wenyu; Yu, Kefu

2017-02-01

A facile strategy to increase the selectivity of heterogeneous Fenton oxidation is investigated. The increase was reached by increasing selective adsorption of heterogeneous Fenton catalyst to a target pollutant. The heterogeneous Fenton catalyst was prepared by a two-step process. First, zeolite particles were imprinted by the target pollutant, methylene blue (MB), in their aggregations, and second, iron ions were loaded on the zeolite aggregations to form the molecule imprinted Fe-zeolites (MI-FZ) Fenton catalyst. Its adsorption amount for MB reached as high as 44.6 mg g -1 while the adsorption amount of un-imprinted Fe-zeolites (FZ) is only 15.6 mg g -1 . Fenton removal efficiency of MI-FZ for MB was 87.7%, being 33.9% higher than that of FZ. The selective Fenton oxidation of MI-FZ for MB was further confirmed by its removal performance for the mixed MB and bisphenol A (BPA) in solution. The removal efficiency of MB was 44.7% while that of BPA was only 14.9%. This fact shows that molecular imprinting is suitable to prepare the Fe-zeolites (FZ)-based Fenton catalyst with high selectivity for removal of target pollutants, at least MB.

Integration of membrane separation and Fenton processes for sanitary landfill leachate treatment.

PubMed

Santos, Amanda Vitória; Andrade, Laura Hamdan de; Amaral, Míriam Cristina Santos; Lange, Liséte Celina

2018-04-06

The appropriate treatment of sanitary landfill leachate is one of the greatest challenges nowadays due to the large volumes of solid waste generated. Thus, the aim of this study is to evaluate the performance of different routes involving the integration of advanced oxidation processes based on Fenton's reagents (AOP-Fenton) and microfiltration (MF) and nanofiltration (NF) membrane processes for the treatment of landfill leachate. MF module configuration (submerged or sidestream) and MF and NF recovery rate were evaluated. The combination of AOP-Fenton, MF and NF proved to be an effective treatment for landfill leachate. High removal efficiencies of chemical oxidation demand (94-96%) and colour (96-99%) were obtained. The configuration named route 3, composed of MF of raw landfill leachate (MF1), POA-Fenton-MF2 of the MF1 concentrate and NF of both MF1 and MF2 permeates, showed a higher global water recovery and was responsible for lower waste generation. It was considered the best one in terms of environmental, technical and economical aspects.

Cosmetic wastewater treatment by coagulation and advanced oxidation processes.

PubMed

Naumczyk, Jeremi; Bogacki, Jan; Marcinowski, Piotr; Kowalik, Paweł

2014-01-01

In this study, the treatment process of three cosmetic wastewater types has been investigated. Coagulation allowed to achieve chemical oxygen demand (COD) removal of 74.6%, 37.7% and 74.0% for samples A (Al2(SO4)3), B (Brentafloc F3) and C (PAX 16), respectively. The Fenton process proved to be effective as well - COD removal was equal to 75.1%, 44.7% and 68.1%, respectively. Coagulation with FeCl3 and the subsequent photo-Fenton process resulted in the best values of final COD removal equal to 92.4%, 62.8% and 90.2%. In case of the Fenton process, after coagulation these values were equal to 74.9%, 50.1% and 84.8%, while in case of the H2O2/UV process, the obtained COD removal was 83.8%, 36.2% and 80.9%. High value of COD removal in the Fenton process carried out for A and C wastewater samples was caused by a significant contribution of the final neutralization/coagulation. Very small effect of the oxidation reaction in the Fenton process in case of sample A resulting from the presence of antioxidants, 'OH radical scavengers' in the wastewater.

Reduction of antibiotic resistance genes in municipal wastewater effluent by advanced oxidation processes.

PubMed

Zhang, Yingying; Zhuang, Yao; Geng, Jinju; Ren, Hongqiang; Xu, Ke; Ding, Lili

2016-04-15

This study investigated the reduction of antibiotic resistance genes (ARGs), intI1 and 16S rRNA genes, by advanced oxidation processes (AOPs), namely Fenton oxidation (Fe(2+)/H2O2) and UV/H2O2 process. The ARGs include sul1, tetX, and tetG from municipal wastewater effluent. The results indicated that the Fenton oxidation and UV/H2O2 process could reduce selected ARGs effectively. Oxidation by the Fenton process was slightly better than that of the UV/H2O2 method. Particularly, for the Fenton oxidation, under the optimal condition wherein Fe(2+)/H2O2 had a molar ratio of 0.1 and a H2O2 concentration of 0.01molL(-1) with a pH of 3.0 and reaction time of 2h, 2.58-3.79 logs of target genes were removed. Under the initial effluent pH condition (pH=7.0), the removal was 2.26-3.35 logs. For the UV/H2O2 process, when the pH was 3.5 with a H2O2 concentration of 0.01molL(-1) accompanied by 30min of UV irradiation, all ARGs could achieve a reduction of 2.8-3.5 logs, and 1.55-2.32 logs at a pH of 7.0. The Fenton oxidation and UV/H2O2 process followed the first-order reaction kinetic model. The removal of target genes was affected by many parameters, including initial Fe(2+)/H2O2 molar ratios, H2O2 concentration, solution pH, and reaction time. Among these factors, reagent concentrations and pH values are the most important factors during AOPs. Copyright © 2016 Elsevier B.V. All rights reserved.

Integration of advanced oxidation processes at mild conditions in wet scrubbers for odourous sulphur compounds treatment.

PubMed

Vega, Esther; Martin, Maria J; Gonzalez-Olmos, Rafael

2014-08-01

The effectiveness of different advanced oxidation processes on the treatment of a multicomponent aqueous solution containing ethyl mercaptan, dimethyl sulphide and dimethyl disulphide (0.5 mg L(-1) of each sulphur compound) was investigated with the objective to assess which one is the most suitable treatment to be coupled in wet scrubbers used in odour treatment facilities. UV/H2O2, Fenton, photo-Fenton and ozone treatments were tested at mild conditions and the oxidation efficiency obtained was compared. The oxidation tests were carried out in magnetically stirred cylindrical quartz reactors using the same molar concentration of oxidants (hydrogen peroxide or ozone). The results show that ozone and photo-Fenton are the most efficient treatments, achieving up to 95% of sulphur compounds oxidation and a mineralisation degree around 70% in 10 min. Furthermore, the total costs of the treatments taking into account the capital and operational costs were also estimated for a comparative purpose. The economic analysis revealed that the Fenton treatment is the most economical option to be integrated in a wet scrubber to remove volatile organic sulphur compounds, as long as there are no space constraints to install the required reactor volume. In the case of reactor volume limitation or retrofitting complexities, the ozone and photo-Fenton treatments should be considered as viable alternatives. Copyright © 2014 Elsevier Ltd. All rights reserved.

Roles of free radicals in NO oxidation by Fenton system and the enhancement on NO oxidation and H2O2 utilization efficiency.

PubMed

Zhao, Haiqian; Dong, Ming; Wang, Zhonghua; Wang, Huaiyuan; Qi, Hanbing

2018-06-20

Low H 2 O 2 utilization efficiency is the main problem when Fenton system was used to oxidize NO in flue gas. To understand the behavior of the free radicals during NO oxidation process in Fenton system is crucial to solving this problem. The oxidation capacity of ·OH and HO 2 · on NO in Fenton system was compared and the useless consumption path of ·OH and HO 2 · that caused the low utilization efficiency of H 2 O 2 were studied. A method to enhance the oxidation ability and H 2 O 2 utilization efficiency by adding reducing additives in Fenton system was proposed. The results showed that both of ·OH and HO 2 · were active substances that oxidize NO. However, the oxidation ability of ·OH radicals was stronger. The vast majority of ·OH and HO 2 · was consumed by rapid reaction ·OH+HO 2 ·→H 2 O+O 2 , which was the primary reason for the low utilization efficiency of H 2 O 2 in Fenton system. Hydroxylamine hydrochloride and ascorbic acid could accelerate the conversion of Fe 3+ to Fe 2+ , thereby increase the generation rate of ·OH and decrease the generation rate of HO 2 ·. As a result, the oxidation ability and H 2 O 2 utilization efficiency were enhanced.

Degradation of sodium dodecyl sulphate in water using solar driven Fenton-like advanced oxidation processes.

PubMed

Bandala, Erick R; Peláez, Miguel A; Salgado, Maria J; Torres, Luis

2008-03-01

Synthetic wastewater samples containing a model surfactant were treated using two different Fenton-like advanced oxidation processes promoted by solar radiation; the photo-Fenton reaction and Co/PMS/UV processes. Comparison between the different experimental conditions was performed by means of the overall surfactant degradation achieved and by obtaining the initial rate in the first 15 min of reaction (IR15). It was found that, for dark Fenton reaction, the maximum surfactant degradation achieved was 14% under low iron and oxidant concentration. Increasing Fenton reagents by one magnitude order, surfactant degradation achieved 63% in 60 min. The use of solar radiation improved the reaction rate by 17% under same conditions and an additional increase of 12.5% was obtained by adjusting initial pH to 2. IR15 values for dark and irradiated Fenton reactions were 0.143 and 0.154 mmol/min, respectively, for similar reaction conditions and this value increased to 0.189 mmol/min when initial pH was adjusted. The use of the Co/PMS system allow us to determine an increase in the degradation rate, for low reaction conditions (1 mM of transition metal; 4 mM oxidant) similar to those used in dark Fenton reaction. Surfactant degradation increased from 3%, for Fenton reaction, to 44.5% in the case of Co/PMS. When solar irradiation was included in the experiments, under same reaction conditions described earlier, surfactant degradation up to 64% was achieved. By increasing Co/PMS reagent concentration by almost 9 times under irradiated conditions, almost complete (>99%) surfactant degradation was reached in 5 min. Comparing IR15 values for Co/PMS and Co/PMS/UV, it allow us to observe that the use of solar radiation increased the degradation rate in one magnitude order when compared with dark experiments and further increase of reagent concentration increased reaction rate twice.

Treatability assessment of polycyclic aromatic hydrocarbons contaminated marine sediments using permanganate, persulfate and Fenton oxidation processes.

PubMed

Shih, Yu-Jen; Binh, Nguyen Thanh; Chen, Chiu-Wen; Chen, Chih-Feng; Dong, Cheng-Di

2016-05-01

Various chemical oxidation techniques, such as potassium permanganate (KMnO4), sodium persulfate (Na2S2O8), Fenton (H2O2/Fe(2+)), and the modified persulfate and Fenton reagents (activated by ferrous complexes), were carried out to treat marine sediments that were contaminated with polycyclic aromatic hydrocarbons (PAHs) and dredged from Kaohsiung Harbor in Taiwan. Experimental results revealed that KMnO4 was the most effective of the tested oxidants in PAH degradation. Owing to the high organic matter content in the sediment that reduced the efficiencies of Na2S2O8 and regular Fenton reactions, a large excess of oxidant was required. Nevertheless, KH2PO4, Na4P2O7 and four chelating agents (EDTA, sodium citrate, oxalic acid, and sodium oxalate) were utilized to stabilize Fe(II) in activating the Na2S2O8 and Fenton oxidations, while Fe(II)-citrate remarkably promoted the PAH degradation. Increasing the molecular weight and number of rings of PAH did not affect the overall removal efficiencies. The correlation between the effectiveness of the oxidation processes and the physicochemical properties of individual PAH was statistically analyzed. The data implied that the reactivity of PAH (electron affinity and ionization potential) affected its treatability more than did its hydrophobicity (Kow, Koc and Sw), particularly using experimental conditions under which PAHs could be effectively oxidized. Copyright © 2016 Elsevier Ltd. All rights reserved.

Advanced oxidation of Reactive Blue 181 solution: a comparison between Fenton and Sono-Fenton process.

PubMed

Basturk, Emine; Karatas, Mustafa

2014-09-01

In this work, the decolorization of C.I. Reactive Blue 181 (RB181), an anthraquinone dye, by Ultrasound and Fe(2+) H2O2 processes was investigated. The effects of operating parameters, such as Fe(2+) dosage, H2O2 dosage, pH value, reaction time and temperature were examined. Process optimisation [pH, ferrous ion (Fe(2+)), hydrogen peroxide (H2O2), and reaction time], kinetic studies and their comparison were carried out for both of the processes. The Sono-Fenton process was performed by indirect sonication in an ultrasonic water bath, which was operated at a fixed 35-kHz frequency. The optimum conditions were determined as [Fe(2+)]=30 mg/L, [H2O2]=50 mg/L and pH=3 for the Fenton process and [Fe(2+)]=10 mg/L, [H2O2]=40 mg/L and pH=3 for the Sono-Fenton process. The colour removals were 88% and 93.5% by the Fenton and Sono-Fenton processes, respectively. The highest decolorization was achieved by the Sono-Fenton process because of the production of some oxidising agents as a result of sonication. The paper also discussed kinetic parameters. The decolorization kinetic of RB181 followed pseudo-second-order reaction (Fenton study) and Behnajady kinetics (Sono-Fenton study). Copyright © 2014 Elsevier B.V. All rights reserved.

Sodium hypochlorite as an alternative to hydrogen peroxide in Fenton process for industrial scale.

PubMed

Behin, Jamshid; Akbari, Abbas; Mahmoudi, Mohsen; Khajeh, Mehdi

2017-09-15

In present work, the treatment of aromatic compounds of simulated wastewater was performed by Fenton and NaOCl/Fe 2+ processes. The model solution was prepared based on the wastewater composition of Diisocyanate unit of Karoon Petrochemical Company/Iran containing Diamino-toluenes, Nitro-phenol, Mononitro-toluene, Nitro-cresol, and Dinitro-toluene. Experiments were conducted in a batch mode to examine the effects of operating variables such as pH, oxidant dosages, ferrous ion concentration and numbers of feeding on COD removal. Taguchi experimental design was used to determine the optimum conditions. The COD removal efficiency under optimum conditions (suggested by Taguchi design) in Fenton and NaOCl/Fe 2+ processes was 88.7% and 83.4%, respectively. The highest contribution factor in Fenton process belongs to pH (47.47%) and in NaOCl/Fe 2+ process belongs to NaOCl/pollutants (50.26%). High regression coefficient (R 2 : 0.98) obtained for Taguchi method, indicates that models are statistically significant and are in well agreement with each other. The NaOCl/Fe 2+ process utilizing a conventional oxidant, in comparison to hydrogen peroxide, is an efficient cost effective process for COD removal from real wastewater, although the removal efficiency is not as high as in Fenton process; however it is a suitable process to replace Fenton process in industrial scale for wastewater involved aromatic compounds with high COD. This process was successfully applied in Karoon Petrochemical Company/Iran. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efficient treatment of an electroplating wastewater containing heavy metal ions, cyanide, and organics by H2O2 oxidation followed by the anodic Fenton process.

PubMed

Zhao, Xu; Wang, Haidong; Chen, Fayuan; Mao, Ran; Liu, Huijuan; Qu, Jiuhui

2013-01-01

A real electroplating wastewater, containing heavy metals, cyanide, and organic contaminants, was treated by electrocoagulation (EC), H2O2 oxidation, H2O2 pre-oxidation followed by EC, and the anodic Fenton process and the efficacy of the processes was compared. Concentration of cyanide, Cu, Ni, Zn, and Cr was largely decreased by EC within 5 min. When the reaction time was extended, removal of residual cyanide, Cu, and Ni was limited. In H2O2 oxidation, the concentration of cyanide decreased from initial 75 to 12 mg L(-1) in 30 min. The effluents from the H2O2 oxidation were further treated by EC or anodic Fenton. In EC, the concentration of total cyanide, Ni, and Cu decreased to below 0.3, 0.5, and 1.5 mg L(-1), respectively. Removal efficiency of chemical oxygen demand by EC was less than 20.0%. By contrast, there was 73.5% reduction by the anodic Fenton process with 5 mM H2O2 at 30 min; this can be attributed to the oxidation induced by hydroxyl radicals generated by the reaction of H2O2 with the electrogenerated Fe(2+). Meanwhile, residual cyanide, Cu, and Ni can also be efficiently removed. Transformation of organic components in various processes was analyzed using UV-visible and fluorescence excitation-emission spectra.

Treatment of olefin plant spent caustic by combination of neutralization and Fenton reaction.

PubMed

Sheu, S H; Weng, H S

2001-06-01

Spent caustic from olefin plants contains much H2S and some mercaptans, phenols and oil. A new treatment process of spent caustic by neutralization followed by oxidation with Fenton's reagent (Fe2+/H2O2) was successfully developed. Over 90% of dissolved H2S were converted to gas phase by neutralization at pH = 5 and T = 70 degrees, and the vent gas stream could be introduced to sulfur recovery plant. The neutralized liquid was oxidized with OH. free radical, which was provided by a Fenton's reagent. The residual sulfides in the neutralized spent caustic were oxidized to less than 0.1 mg/L. The total COD removal of spent caustic is over 99.5% and the final COD value of the effluent can be lower than 100 mg/L under the following oxidation conditions: reaction time = 50 min, T = 90 degrees, Fe2+ = 100 mg/L, and a stoichiometric H2O2/COD = 1.1. The value is better than the 800 mg/L value obtained by common WAO process. The optimum pH of the Fenton reaction is around 2 for this process, and the oxidation step can maintain a pH value in the range of 1.8-2.4. Moreover, the iron catalyst can be recycled without affecting process effectiveness thus preventing secondary pollution.

Simultaneous Removal of Thallium and EDTA by Fenton Process

NASA Astrophysics Data System (ADS)

Xu, Ruibing; Huang, Xuexia; Li, Huosheng; Su, Minhua; Chen, Diyun

2018-01-01

The wastewater containing heavy metals and organic pollutants is widely discharged from industries. Because of the coexistence of heavy metals and organic pollutants, the treatment of such wastewater is very difficult. Fenton process is considered to be one of the most effective approaches for the degradation of organic pollutants in aqueous solution due to the strong oxidative ability of hydroxyl radical which generated from the Fenton process. Apart from this, heavy metals are able to be removed during Fenton process owning to the synergic effect of coagulation and precipitation. In this work, pollutants of thallium and EDTA were successfully removed via the Fenton process. A series of single-factor experiments were designed and performed to achieve an optimal reaction conditions for the removal of both thallium and EDTA. Results showed that the removal efficiencies of thallium and TOC could be as high as 96.54% and 70.42%, respectively. The outcomes from our study demonstrate that Fenton process is a promising method for the purification of wastewater containing thallium and EDTA.

Review of iron-free Fenton-like systems for activating H2O2 in advanced oxidation processes.

PubMed

Bokare, Alok D; Choi, Wonyong

2014-06-30

Iron-catalyzed hydrogen peroxide decomposition for in situ generation of hydroxyl radicals (HO(•)) has been extensively developed as advanced oxidation processes (AOPs) for environmental applications. A variety of catalytic iron species constituting metal salts (in Fe(2+) or Fe(3+) form), metal oxides (e.g., Fe2O3, Fe3O4), and zero-valent metal (Fe(0)) have been exploited for chemical (classical Fenton), photochemical (photo-Fenton) and electrochemical (electro-Fenton) degradation pathways. However, the requirement of strict acidic conditions to prevent iron precipitation still remains the bottleneck for iron-based AOPs. In this article, we present a thorough review of alternative non-iron Fenton catalysts and their reactivity towards hydrogen peroxide activation. Elements with multiple redox states (like chromium, cerium, copper, cobalt, manganese and ruthenium) all directly decompose H2O2 into HO(•) through conventional Fenton-like pathways. The in situ formation of H2O2 and decomposition into HO(•) can be also achieved using electron transfer mechanism in zero-valent aluminum/O2 system. Although these Fenton systems (except aluminum) work efficiently even at neutral pH, the H2O2 activation mechanism is very specific to the nature of the catalyst and critically depends on its composition. This review describes in detail the complex mechanisms and emphasizes on practical limitations influencing their environmental applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Aerobic SMBR/reverse osmosis system enhanced by Fenton oxidation for advanced treatment of old municipal landfill leachate.

PubMed

Zhang, Guoliang; Qin, Lei; Meng, Qin; Fan, Zheng; Wu, Dexin

2013-08-01

A novel combined process of Fenton oxidation, submerged membrane bioreactor (SMBR) and reverse osmosis (RO) was applied as an appropriate option for old municipal landfill leachate treatment. Fenton process was designed to intensively solve the problem of non-biodegradable organic pollutant removal and low biodegradability of leachate, although the removal of ammonia-nitrogen was similar to 10%. After SMBR treatment, it not only presented a higher removal efficiency of organics, but also exhibited high ammonia-nitrogen removal of 80% on average. The variation of extracellular polymeric substance (EPS) content, zeta potential, and particle size of flocs after Fenton effluent continually fed in SMBR was found to be benefit for alleviating membrane fouling. Finally, three kinds of RO membranes (RE, CPA, and BW) were applied to treat SMBR effluents and successfully met wastewater re-utilization requirement. Compared with simple RO process, the troublesome membrane fouling can be effectively reduced in the combined process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Advanced treatment of biologically pretreated coal gasification wastewater by a novel heterogeneous Fenton oxidation process.

PubMed

Zhuang, Haifeng; Han, Hongjun; Ma, Wencheng; Hou, Baolin; Jia, Shengyong; Zhao, Qian

2015-07-01

Sewage sludge from a biological wastewater treatment plant was converted into sewage sludge based activated carbon (SBAC) with ZnCl2 as activation agent, which was used as a support for ferric oxides to form a catalyst (FeOx/SBAC) by a simple impregnation method. The new material was then used to improve the performance of Fenton oxidation of real biologically pretreated coal gasification wastewater (CGW). The results indicated that the prepared FeOx/SBAC significantly enhanced the pollutant removal performance in the Fenton process, so that the treated wastewater was more biodegradable and less toxic. The best performance was obtained over a wide pH range from 2 to 7, temperature 30°C, 15 mg/L of H2O2 and 1g/L of catalyst, and the treated effluent concentrations of COD, total phenols, BOD5 and TOC all met the discharge limits in China. Meanwhile, on the basis of significant inhibition by a radical scavenger in the heterogeneous Fenton process as well as the evolution of FT-IR spectra of pollutant-saturated FeOx/BAC with and without H2O2, it was deduced that the catalytic activity was responsible for generating hydroxyl radicals, and a possible reaction pathway and interface mechanism were proposed. Moreover, FeOx/SBAC showed superior stability over five successive oxidation runs. Thus, heterogeneous Fenton oxidation of biologically pretreated CGW by FeOx/SBAC, with the advantages of being economical, efficient and sustainable, holds promise for engineering application. Copyright © 2015. Published by Elsevier B.V.

Comparison of Fenton and Fenton-like oxidation for the treatment of cosmetic wastewater.

PubMed

Bautista, P; Casas, J A; Zazo, J A; Rodriguez, J J; Mohedano, A F

2014-01-01

The treatment of cosmetic wastewaters by Fenton (Fe²⁺/H₂O₂) and Fenton-like (Fe³⁺/H₂O₂) oxidation has been studied. From batch and continuous experiments it has been proved that both versions of the Fenton process lead to quite similar results in terms of chemical oxygen demand (COD) and total organic carbon reduction although the COD shows a slightly higher rate in the early stages of reaction. COD reductions of around 55% after 2 h reaction time and 75-80% with 4 h residence time were reached in batch and continuous experiments, respectively, conducted at pH around 3, ambient temperature (20 °C), with 200 mg/L of Fe dose and an initial H₂O₂/COD weight ratio corresponding to the theoretical stoichiometric value. Achieving the locally allowable limit of COD for industrial wastewater discharge into the municipal sewer system takes no more than 30 min reaction time under those conditions by both Fenton systems. However, the Fenton-like process, where iron is fed as Fe(3+), would be preferable for industrial applications since the ferric sludge resulting upon final neutralization of the effluent can be recycled to the process. A second-order kinetic equation with respect to COD fitted fairly well the experimental results at different temperatures, thus providing a simple practical tool for design purposes.

Introducing saccharic acid as an efficient iron chelate to enhance photo-Fenton degradation of organic contaminants.

PubMed

Subramanian, Gokulakrishnan; Madras, Giridhar

2016-11-01

The identification of iron chelates that can enhance photo-Fenton degradation is of great interest in the field of advanced oxidation process. Saccharic acid (SA) is a polyhydroxy carboxylic acid and completely non-toxic. Importantly, it can effectively bind Fe(III) as well as induce photoreduction of Fe(III). Despite having these interesting properties, the effect of SA on photo-Fenton degradation has not been studied. Herein, we demonstrate the first assessment of SA as an iron chelate in photo-Fenton process using methylene blue (MB) as a model organic contaminant. Our results demonstrate that SA has the ability to (i) enhance the photo-Fenton degradation of MB by about 11 times at pH 4.5 (ii) intensify photochemical reduction of Fe(III) to Fe(II) by about 17 times and (iii) accelerate the rate of consumption of H 2 O 2 in photo-Fenton process by about 5 times (iv) increase the TOC reduction by about 2 times and (v) improve the photo-Fenton degradation of MB in the presence of a variety of common inorganic ions and organic matter. The influential properties of SA on photo-Fenton degradation is attributed to the efficient photochemical reduction of Fe(III) via LMCT (ligand to metal charge transfer reaction) to Fe(II), which then activated H 2 O 2 to generate OH and accelerated photo-Fenton degradation efficiency. Moreover, the effect of operational parameters such as oxidant: contaminant (H 2 O 2 : MB) ratio, catalyst: contaminant (Fe(III)SA: MB) ratio, Fe(III): SA stoichiometry and pH on the degradation of MB by photo-Fenton in the presence of SA is demonstrated. Importantly, SA assisted photo-Fenton caused effective degradation of MB and 4-Chlorophenol under natural sunlight irradiation in natural water matrix. The findings strongly support SA as a deserving iron chelate to enhance photo-Fenton degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Complete removal of AHPS synthetic dye from water using new electro-fenton oxidation catalyzed by natural pyrite as heterogeneous catalyst.

PubMed

Labiadh, Lazhar; Oturan, Mehmet A; Panizza, Marco; Hamadi, Nawfel Ben; Ammar, Salah

2015-10-30

The mineralization of a new azo dye - the (4-amino-3-hydroxy-2-p-tolylazo-naphthalene-1-sulfonic acid) (AHPS) - has been studied by a novel electrochemical advanced oxidation process (EAOP), consisting in electro-Fenton (EF) oxidation, catalyzed by pyrite as the heterogeneous catalyst - the so-called 'pyrite-EF'. This solid pyrite used as heterogeneous catalyst instead of a soluble iron salt, is the catalyst the system needs for production of hydroxyl radicals. Experiments were performed in an undivided cell equipped with a BDD anode and a commercial carbon felt cathode to electrogenerate in situ H2O2 and regenerate ferrous ions as catalyst. The effects on operating parameters, such as applied current, pyrite concentration and initial dye content, were investigated. AHPS decay and mineralization efficiencies were monitored by HPLC analyses and TOC measurements, respectively. Experimental results showed that AHPS was quickly oxidized by hydroxyl radicals (OH) produced simultaneously both on BDD surface by water discharge and in solution bulk from electrochemically assisted Fenton's reaction with a pseudo-first-order reaction. AHPS solutions with 175 mg L(-1) (100 mg L(-1) initial TOC) content were then almost completely mineralized in 8h. Moreover, the results demonstrated that, under the same conditions, AHPS degradation by pyrite electro-Fenton process was more powerful than the conventional electro-Fenton process. Copyright © 2015 Elsevier B.V. All rights reserved.

Fenton oxidation to remediate PAHs in contaminated soils: A critical review of major limitations and counter-strategies.

PubMed

Usman, M; Hanna, K; Haderlein, S

2016-11-01

Fenton oxidation constitutes a viable remediation strategy to remove polycyclic aromatic hydrocarbons (PAHs) in contaminated soils. This review is intended to illustrate major limitations associated with this process like acidification, PAH unavailability, and deterioration of soil quality along with associated factors, followed by a critical description of various developments to overcome these constraints. Considering the limitation that its optimal pH is around 3, traditional Fenton treatment could be costly, impractical in soil due to the high buffering capacity of soils and associated hazardous effects. Use of various chelating agents (organic or inorganic) allowed oxidation at circumneutral pH but factors like higher oxidant demand, cost and toxicity should be considered. Another alternative is the use of iron minerals that can catalyze Fenton-like oxidation over a wide range of pH, but mobility of these particles in soils (i.e. saturated and unsaturated zones) should be investigated prior to in-situ applications. The PAH-unavailability is the crucial limitation hindering their effective degradation. Research data is compiled describing various strategies to address this issue like the use of availability enhancement agents, extraction or thermal pretreatment. Last section of this review is devoted to describe the effects of various developments in Fenton treatment onto soil quality and native microbiota. Finally, research gaps are discussed to suggest future directions in context of applying Fenton oxidation to remediate contaminated soils. Copyright © 2016 Elsevier B.V. All rights reserved.

Decolorization of distillery spent wash effluent by electro oxidation (EC and EF) and Fenton processes: A comparative study.

PubMed

David, Charles; Arivazhagan, M; Tuvakara, Fazaludeen

2015-11-01

In this study, laboratory scale experiments were performed to degrade highly concentrated organic matter in the form of color in the distillery spent wash through batch oxidative methods such as electrocoagulation (EC), electrofenton (EF) and Fenton process. The effect of corresponding operating parameters, namely initial pH: 2-10; current intensity: 1-5A; electrolysis time: 0.5-4h; agitation speed: 100-500rpm; inter-electrode distance: 0.5-4cm and Fenton's reagent dosage: 5-40mg/L was employed for optimizing the process of spent wash color removal. The performance of all the three processes was compared and assessed in terms of percentage color removal. For EC, 79% color removal was achieved using iron electrodes arranged with 0.5cm of inter-electrode space and at optimum conditions of pH 7, 5A current intensity, 300rpm agitation speed and in 2h of electrolysis time. In EF, 44% spent wash decolorization was observed using carbon (graphite) electrodes with an optimum conditions of 0.5cm inter-electrode distance, pH 3, 4A current intensity, 20mg/L FeSO4 and agitation speed of 400rpm for 3h of electrolysis time. By Fenton process, 66% decolorization was attained by Fenton process at optimized conditions of pH 3, 40mg/L of Fenton's reagent and at 500rpm of agitation speed for 4h of treatment time. Copyright © 2015 Elsevier Inc. All rights reserved.

Solar Fenton and solar TiO2 catalytic treatment of ofloxacin in secondary treated effluents: evaluation of operational and kinetic parameters.

PubMed

Michael, I; Hapeshi, E; Michael, C; Fatta-Kassinos, D

2010-10-01

Two different technical approaches based on advanced oxidation processes (AOPs), solar Fenton homogeneous photocatalysis (hv/Fe(2+)/H(2)O(2)) and heterogeneous photocatalysis with titanium dioxide (TiO(2)) suspensions were studied for the chemical degradation of the fluoroquinolone ofloxacin in secondary treated effluents. A bench-scale solar simulator in combination with an appropriate photochemical batch reactor was used to evaluate and select the optimal oxidation conditions of ofloxacin spiked in secondary treated domestic effluents. The concentration profile of the examined substrate during degradation was determined by UV/Vis spectrophotometry. Mineralization was monitored by measuring the dissolved organic carbon (DOC). The concentrations of Fe(2+) and H(2)O(2) were the key factors for the solar Fenton process, while the most important parameter of the heterogeneous photocatalysis was proved to be the catalyst loading. Kinetic analyses indicated that the photodegradation of ofloxacin can be described by a pseudo-first-order reaction. The rate constant (k) for the solar Fenton process was determined at different Fe(2+) and H(2)O(2) concentrations whereas the Langmuir-Hinshelwood (LH) kinetic expression was used to assess the kinetics of the heterogeneous photocatalytic process. The conversion of ofloxacin depends on several parameters based on the various experimental conditions, which were investigated. A Daphnia magna bioassay was used to evaluate the potential toxicity of the parent compound and its photo-oxidation by-products in different stages of oxidation. In the present study solar Fenton has been demonstrated to be more effective than the solar TiO(2) process, yielding complete degradation of the examined substrate and DOC reduction of about 50% in 30 min of the photocatalytic treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Economic evaluation of a combined photo-Fenton/MBR process using pesticides as model pollutant. Factors affecting costs.

PubMed

Sánchez Pérez, José Antonio; Román Sánchez, Isabel María; Carra, Irene; Cabrera Reina, Alejandro; Casas López, José Luis; Malato, Sixto

2013-01-15

The aim of this paper is to carry out an economic assessment on a solar photo-Fenton/MBR combined process to treat industrial ecotoxic wastewater. This study focuses on the impact of the contamination present in wastewater, the photochemical oxidation, the use of an MBR as biological process and the plant size on operating and amortization costs. As example of ecotoxic pollutant, a mixture of five commercial pesticides commonly used in the Mediterranean area has been used, ranging from 500 mg/L to 50mg/L, expressed as dissolved organic carbon concentration. The economic evaluation shows that (i) the increase in pollution load does not always involve an increase in photo-Fenton costs because they also depend on organic matter mineralization; (ii) the use of an MBR process permits lower photochemical oxidation requirements than other biological treatments, resulting in approximately 20% photo-Fenton cost reduction for highly polluted wastewater; (iii) when pollution load decreases, the contribution of reactant consumption to the photo-Fenton process costs increase with regard to amortization costs; (iv) 30% total cost reduction can be gained treating higher daily volumes, obtaining competitive costs that vary from 1.1-1.9 €/m(3), depending on the pollution load. Copyright © 2012 Elsevier B.V. All rights reserved.

Oxalate enhanced degradation of Orange II in heterogeneous UV-Fenton system catalyzed by Fe3O4@γ-Fe2O3 composite.

PubMed

Dai, Huiwang; Xu, Shuying; Chen, Jianxin; Miao, Xiaozeng; Zhu, Jianxi

2018-05-01

Oxalate enhanced mechanism of Fe 3 O 4 @γ-Fe 2 O 3 was developed to provide novel insight into catalytic process regulation of iron oxide catalysts in heterogeneous UV-Fenton system. And the iron oxide composite of Fe 3 O 4 @γ-Fe 2 O 3 was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FTIR) spectroscopy and nitrogen adsorption-desorption isotherms. The results showed that large amount of iron could be leached from catalyst in the presence of oxalate, which promoted the homogeneous UV-Fenton reactions in solution. Orange II degradation could be significantly enhanced with the increase of the ratio of homogeneous UV-Fenton process to heterogeneous UV-Fenton process. The optimum concentration of oxalate determined by experiment was 0.5 mM in oxalate enhanced heterogeneous UV-Fenton system. On this condition, the pseudo-first-order rate constant value of Orange II degradation was 0.314 min -1 , which was 2.3 times as high as that in heterogeneous UV-Fenton system. The removal rates of color and TOC were 100% and 86.6% after 20 min and 120 min treatment, respectively. In addition, the iron ions in solution could be almost completely adsorbed back to the catalyst surface in later degradation stages of Orange II. During the recycle experiments, the results showed that the increase of pH in solution and the sorption of intermediates on the catalyst surface would hinder oxalate enhanced process and lead to a decrease of degradation rate of Orange II in oxalate enhanced heterogeneous UV-Fenton system. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sequential pretreatment for cell disintegration of municipal sludge in a neutral Bio-electro-Fenton system.

PubMed

Yu, Qilin; Jin, Xiaochen; Zhang, Yaobin

2018-05-15

Sludge cell disruption was generally considered as the rate-limiting step for the anaerobic digestion of waste activated sludge (WAS). Advanced oxidation processes and bio-electro-chemical systems were recently reported to enhance the hydrolysis of WAS and sludge cell disruption, while the cell-breaking processes of these systems remain unclear yet. In this study, an innovative Bio-electro-Fenton system was developed to pretreat the WAS sequentially with cathode Fenton process and anode anaerobic digestion. Significant cell disruption and dissolution intracellular organics were founded after the treatment. X-ray photoelectron spectroscopy (XPS) analysis and fourier transform infrared spectroscopy (FT-IR) spectra indicated that Gram-negative bacteria were more sensitive to free radicals yielded in cathode to induce a chain reaction that destroyed the lipid-contained outer membrane, while Gram-positive bacteria with thick peptidoglycan layer were liable to be biologically decomposed in the anode. Compared with the oxidation of organic matters in the cathode Fenton, the secretion of enzyme increased in the anode which was beneficial to break down the complex matters (peptidoglycans) into simples that were available for anode oxidation by exoelectrogens. The results also showed a possible prospect for the application of this sequential pretreatment in bio-electro-Fenton systems to disrupt sludge cells and enhance the anaerobic digestion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Electro-Fenton oxidation of reverse osmosis concentrate from sanitary landfill leachate: Evaluation of operational parameters.

PubMed

Fernandes, Annabel; Labiadh, Lazhar; Ciríaco, Lurdes; Pacheco, Maria José; Gadri, Abdellatif; Ammar, Salah; Lopes, Ana

2017-10-01

The electro-Fenton oxidation of a concentrate from reverse osmosis of a sanitary landfill leachate, with an initial chemical oxygen demand (COD) of 42 g L -1 , was carried out using a carbon-felt cathode and a boron doped diamond anode. The influence of the applied current intensity, initial pH and dissolved iron initial concentration on the electro-Fenton process was assessed. For the experimental conditions used, results showed that the initial pH is the parameter that more strongly influences the current efficiency of the electro-Fenton process, being this influence more pronounced on the oxidation rate than on the mineralization rate of the organic matter. The increase in iron initial concentration was found to be detrimental, since the natural amount of iron present in the effluent, 73 mg L -1 of total iron and 61 mg L -1 of dissolved iron, was sufficient to ensure the electro-Fenton process at the applied intensities - 0.2-1.4 A. For the more favourable conditions studied, initial pH of 3 and natural iron concentration, it was found an increase in the organic load and nitrogen removals with the applied current intensity. For the highest current intensity applied, a COD removal of 16.7 g L -1 was achieved after 8-h experiments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of conventional Fenton and ultraviolet-assisted oxidation processes for the treatment of reverse osmosis retentate from a paper mill.

PubMed

Hermosilla, Daphne; Merayo, Noemí; Ordóñez, Ruth; Blanco, Angeles

2012-06-01

According to current environmental legislation concerned with water scarcity, paper industry is being forced to adopt a zero liquid effluent policy. In consequence, reverse osmosis (RO) systems are being assessed as the final step of effluent treatment trains aiming to recover final wastewater and reuse it as process water. One of the most important drawbacks of these treatments is the production of a retentated stream, which is usually highly loaded with biorecalcitrant organic matter and inorganics; and this effluent must meet current legislation stringent constraints before being ultimately disposed. The treatment of biorefractory RO retentate from a paper mill by several promising advanced oxidation processes (AOPs) - conventional Fenton, photo-Fenton and photocatalysis - was optimized considering the effect and interaction of reaction parameters; particularly using response surface methodology (RSM) when appropriate (Fenton processes). The economical cost of these treatments was also comparatively assessed. Photo-Fenton process was able to totally remove the COD of the retentate, and resulted even operatively cheaper at high COD removal levels than conventional Fenton, which achieved an 80% reduction of the COD at best. In addition, although these optimal results were produced at pH=2.8, it was also tested that Fenton processes are able to achieve good COD reduction efficiencies (>60%) without adjusting the initial pH value, provided the natural pH of this wastewater was close to neutral. Finally, although TiO(2)-photocatalysis showed the least efficient and most expensive figures, it improved the biodegradability of the retentate, so its combination with a final biological step almost achieved the total removal of the COD. Copyright © 2011 Elsevier Ltd. All rights reserved.

Kaolinite adsorption-regeneration system for dyestuff treatment by Fenton based processes.

PubMed

Rosales, Emilio; Anasie, Delia; Pazos, Marta; Lazar, Iuliana; Sanromán, M Angeles

2018-05-01

The regeneration and reuse of adsorbents is a subject of interest nowadays in order to reduce the pollution and the wastes generated in the adsorption wastewater treatment. In this work, the regeneration of the spent kaolinite by different advanced oxidation processes (Fenton, electro-Fenton and electrokinetic-Fenton) was evaluated. Initially, it was confirmed the ability of a low cost clayey material, kaolinite, for the adsorption of model dye such as Rhodamine B showing Freundlich isotherm fitting. Then, the regeneration and consequent degradation of the pollutant in the adsorbent by Fenton based processes was carried out. The role of different parameters affecting the regeneration process (H 2 O 2 :Fe 2+ ratio, liquid:solid ratio) were evaluated. Working at 100:1 H 2 O 2 :Fe 2+ ratio and 30min near complete dye removal (around 97%) from kaolinite was obtained by Fenton treatment. After that, a two-stage treatment for adsorption-regeneration was evaluated during five treatment cycles demonstrating its viability for regeneration of the adsorbent through dye degradation. Based on the successful application of Fenton technique, the improvement of the treatment by electro-Fenton and electrokinetic-Fenton were studied for different solid:liquid ratios achieving satisfactory regeneration values. Copyright © 2017 Elsevier B.V. All rights reserved.

Use of Both Anode and Cathode Reactions in Wastewater Treatment

NASA Astrophysics Data System (ADS)

Brillas, Enric; Sirés, Ignasi; Cabot, Pere LluíS.

Here, we describe the fundamentals, laboratory experiments, and environmental applications of indirect electrooxidation methods based on H2O2 electrogeneration such as electro-Fenton, photoelectro-Fenton and peroxicoagulation for the treatment of acidic wastewaters containing toxic and recalcitrant organics. These methods are electrochemical advanced oxidation processes that can be used in divided and undivided electrolytic cells in which pollutants are oxidized by hydroxyl radical (•OH) produced from anode and/or cathode reactions. H2O2 is generated from the two-electron reduction of O2 at reticulated vitreous carbon, graphite, carbon-felt, and O2-diffusion cathodes. The most usual method is electro-Fenton where Fe2 + added to the wastewater reacts with electrogenerated H2O2 to yield •OH and Fe3 + from Fenton's reaction. An advantage of this technique is that Fe2 + is continuously regenerated from cathodic reduction of Fe3 +. The characteristics of different electro-Fenton systems where pollutants are simultaneously destroyed by •OH formed in the medium from Fenton's reaction and at the anode surface from water oxidation are explained. The effect of the anode [Pt or boron-doped diamond (BDD)] and cathode (carbon-felt or O2-diffusion) on the degradation rate of persistent industrial by-products, herbicides, pharmaceuticals, dyes, etc. is examined. Initial pollutants react much more rapidly with •OH formed in the medium and their degradation sequences are discussed from aromatic intermediates and finally short aliphatic acids are detected. The synergetic positive catalytic effect of Cu2 + on the electro-Fenton process is evidenced. The photoelectro-Fenton method involves the irradiation of the wastewater with UVA light that rapidly photodecomposes complexes of Fe3 + with final carboxylic acids enhancing total decontamination. The peroxicoagulation method uses a sacrificial Fe anode that is continuously oxidized to Fe2 + and organics are either mineralized with •OH formed from both electrogenerated Fe2 + and H2O2 or removed by parallel coagulation with the FeOH3 precipitate formed from the excess of Fe3 + generated from Fenton's reaction.

Cosmetic wastewater treatment using the Fenton, Photo-Fenton and H2O2/UV processes.

PubMed

Marcinowski, Piotr P; Bogacki, Jan P; Naumczyk, Jeremi H

2014-01-01

Advanced Oxidation Processes (AOPs), such as the Fenton, photo-Fenton and H2O2/UV processes, have been investigated for the treatment of cosmetic wastewaters that were previously coagulated by FeCl3. The Photo-Fenton process at pH 3.0 with 1000/100 mg L(-1) H2O2/Fe(2+) was the most effective (74.0% Chemical Oxygen Demand (COD) removal). The Fenton process with 1200/500 mg L(-1) H2O2/Fe(2+) achieved a COD removal of 72.0%, and the H2O2/UV process achieved a COD removal of 47.0%. Spreading the H2O2 doses over time to obtain optimal conditions did not improve COD removal. The kinetics of the Fenton and photo-Fenton processes may be described by the following equation: d[COD]/dt = -a[COD] t(m) (t represents time and a and m are constants). The rate of COD removal by the H2O2/UV process may be described by a second-order reaction equation. Head Space, Solid-Phase MicroExtraction, Gas Chromatography and Mass Spectrometry (HS-SPME-GC-MS) were used to identify 48 substances in precoagulated wastewater. Among these substances, 26 were fragrances. Under optimal AOP conditions, over 99% of the identified substances were removed in 120 min.

Decontamination of soil washing wastewater using solar driven advanced oxidation processes.

PubMed

Bandala, Erick R; Velasco, Yuridia; Torres, Luis G

2008-12-30

Decontamination of soil washing wastewater was performed using two different solar driven advanced oxidation processes (AOPs): the photo-Fenton reaction and the cobalt/peroxymonosulfate/ultraviolet (Co/PMS/UV) process. Complete sodium dodecyl sulphate (SDS), the surfactant agent used to enhance soil washing process, degradation was achieved when the Co/PMS/UV process was used. In the case of photo-Fenton reaction, almost complete SDS degradation was achieved after the use of almost four times the actual energy amount required by the Co/PMS/UV process. Initial reaction rate in the first 15min (IR15) was determined for each process in order to compare them. Highest IR15 value was determined for the Co/PMS/UV process (0.011mmol/min) followed by the photo-Fenton reaction (0.0072mmol/min) and the dark Co/PMS and Fenton processes (IR15=0.002mmol/min in both cases). Organic matter depletion in the wastewater, as the sum of surfactant and total petroleum hydrocarbons present (measured as chemical oxygen demand, COD), was also determined for both solar driven processes. It was found that, for the case of COD, the highest removal (69%) was achieved when photo-Fenton reaction was used whereas Co/PMS/UV process yielded a slightly lower removal (51%). In both cases, organic matter removal achieved was over 50%, which can be consider proper for the coupling of the tested AOPs with conventional wastewater treatment processes such as biodegradation.

Kinetic degradation of guar gum in oilfield wastewater by photo-Fenton process.

PubMed

Wang, Shunwu; Li, Ziwang; Yu, Qinglong

2017-01-01

Guar gum is considered as a main component of oilfield wastewater. This work is intended to optimize the experimental conditions (H 2 O 2 dosage, Fe 2+ dosage, initial concentration of organics, initial pH and temperature) for the maximum oxidative degradation of guar gum by Fenton's reagent. The kinetics of guar gum removal were evaluated by means of the chemical oxygen demand (COD) and the absorbance measurements. The batch experiment results showed that the optimum conditions were: H 2 O 2 dosage, 10,000 mg/L; Fe 2+ dosage, 2,000 mg/L; initial concentration of organics, 413 mg/L; pH, 3 and temperature, 35 °C, under which the COD removal could reach 61.07% and fairly good stability could be obtained. Under the optimum experimental conditions, using UV irradiation to treat the wastewater, the photo-Fenton systems can successfully eliminate COD from guar gum solution. The COD removal always obeyed a pseudo-first-order kinetics and the degradation rate (k app ) was increased by 25.7% in the photo-Fenton process compared to the Fenton process. The photo-Fenton system needed less time and consequently less quantity of H 2 O 2 to obtain the same results as the Fenton process. The photo-Fenton process needs a dose of H 2 O 2 20.46% lower than that used in the Fenton process to remove 79.54% of COD. The cost of the photo/Fenton process amounted to RMB9.43/m 3 , which was lower than that of the classic Fenton process alone (RMB10.58/m 3 ) and the overall water quality of the final effluent could meet the class Ι national wastewater discharge standard for the petrochemical industry of China.

Effect of the ultrasound-Fenton oxidation process with the addition of a chelating agent on the removal of petroleum-based contaminants from soil.

PubMed

Li, Ying; Li, Fangmin; Li, Fanxiu; Yuan, Fuqian; Wei, Pingfang

2015-12-01

The effects of ultrasonic irradiation, the chelating agent modified Fenton reaction, and a combination of ultrasound and the Fenton method in removing petroleum contaminants from a soil were studied. The results showed that the contaminant removal rate of the Fenton treatment combined with an oxalic acid chelating agent was 55.6% higher than that without a chelating agent. The average removal rate of the contaminants using the ultrasound-Fenton treatment was 59.0% higher than that without ultrasonic treatment. A combination of ultrasound and an Fe(2+)/Fe(3+)-oxalate complex-modified Fenton reagent resulted in significantly higher removal rates of n-alkanes (C(n)H(2n+2), n < 28), isoprenoid hydrocarbons, aromatic hydrocarbons, and saturated polycyclic terpenes compared with the ultrasound treatment alone or the Fenton method. The Fenton reaction and the ultrasound-Fenton treatment can unselectively remove multiple components of residual hydrocarbons and a number of benzene rings in polycyclic aromatic hydrocarbons. The chemistry of the heterocyclic compounds and the position and number of substituents can affect the degradation process.

Comparison of various advanced oxidation processes for the degradation of 4-chloro-2 nitrophenol.

PubMed

Saritha, P; Aparna, C; Himabindu, V; Anjaneyulu, Y

2007-11-19

In the present study an attempt is made efficiently to degrade USEPA listed 4-chloro-2-nitrophenol (4C-2-NP), widely available in bulk drug and pesticide wastes using various advanced oxidation processes (AOPs). A comparative assessment using various AOPs (UV, H(2)O(2,) UV/H(2)O(2), Fenton, UV/Fenton and UV/TiO(2)) was attempted after initial optimization studies, viz., varying pH, peroxide concentration, iron concentration, and TiO(2) loading. The degradation of the study compound was estimated using chemical oxygen demand (COD) reduction and compound reduction using spectrophotometric methods and further validated with high performance liquid chromatography (HPLC). The degradation trends followed the order: UV/Fenton > UV/TiO(2) > UV/H(2)O(2) > Fenton > H(2)O(2) > UV(.) It can be inferred from the studies that UV/Fenton was the most effective in partial mineralization of 4C-2-NP. However, lower costs were obtained with H(2)O(2). Kinetic constants were evaluated using first order equations to determine the rate constant K.

Current advances and trends in electro-Fenton process using heterogeneous catalysts - A review.

PubMed

Poza-Nogueiras, Verónica; Rosales, Emilio; Pazos, Marta; Sanromán, M Ángeles

2018-06-01

Over the last decades, advanced oxidation processes have often been used alone, or combined with other techniques, for remediation of ground and surface water pollutants. The application of heterogeneous catalysis to electrochemical advanced oxidation processes is especially useful due to its efficiency and environmental safety. Among those processes, electro-Fenton stands out as the one in which heterogeneous catalysis has been broadly applied. Thus, this review has introduced an up-to-date collation of the current knowledge of the heterogeneous electro-Fenton process, highlighting recent advances in the use of different catalysts such as iron minerals (pyrite, magnetite or goethite), prepared catalysts by the load of metals in inorganic and organic materials, nanoparticles, and the inclusion of catalysts on the cathode. The effects of physical-chemical parameters as well as the mechanisms involved are critically assessed. Finally, although the utilization of this process to remediation of wastewater overwhelmingly outnumber other utilities, several applications have been described in the context of regeneration of adsorbent or the remediation of soils as clear examples of the feasibility of the electro-Fenton process to solve different environmental problems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Quantitative methylene blue decolourisation assays as rapid screening tools for assessing the efficiency of catalytic reactions.

PubMed

Kruid, Jan; Fogel, Ronen; Limson, Janice Leigh

2017-05-01

Identifying the most efficient oxidation process to achieve maximum removal of a target pollutant compound forms the subject of much research. There exists a need to develop rapid screening tools to support research in this area. In this work we report on the development of a quantitative assay as a means for identifying catalysts capable of decolourising methylene blue through the generation of oxidising species from hydrogen peroxide. Here, a previously described methylene blue test strip method was repurposed as a quantitative, aqueous-based spectrophotometric assay. From amongst a selection of metal salts and metallophthalocyanine complexes, monitoring of the decolourisation of the cationic dye methylene blue (via Fenton-like and non-Fenton oxidation reactions) by the assay identified the following to be suitable oxidation catalysts: CuSO 4 (a Fenton-like catalyst), iron(II)phthalocyanine (a non-Fenton oxidation catalyst), as well as manganese(II) phthalocyanine. The applicability of the method was examined for the removal of bisphenol A (BPA), as measured by HPLC, during parallel oxidation experiments. The order of catalytic activity was identified as FePc > MnPc > CuSO 4 for both BPA and MB. The quantitative MB decolourisation assay may offer a rapid method for screening a wide range of potential catalysts for oxidation processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electrochemical treatment of concentrate from reverse osmosis of sanitary landfill leachate.

PubMed

Labiadh, Lazhar; Fernandes, Annabel; Ciríaco, Lurdes; Pacheco, Maria José; Gadri, Abdellatif; Ammar, Salah; Lopes, Ana

2016-10-01

Conventional sanitary landfill leachate treatment has recently been complemented and, in some cases, completely replaced by reverse osmosis technology. Despite the good quality of treated water, the efficiency of the process is low and a large volume of reverse osmosis concentrate has to be either discharged or further treated. In this study, the use of anodic oxidation combined with electro-Fenton processes to treat the concentrate obtained in the reverse osmosis of sanitary landfill leachate was evaluated. The anodic oxidation pretreatment was performed in a pilot plant using an electrochemical cell with boron-doped diamond electrodes. In the electro-Fenton experiments, a boron-doped diamond anode and carbon-felt cathode were used, and the influence of the initial pH and iron concentration were studied. For the experimental conditions, the electro-Fenton assays performed at an initial pH of 3 had higher organic load removal levels, whereas the best nitrogen removal was attained when the electrochemical process was performed at the natural pH of 8.8. The increase in the iron concentration had an adverse impact on treatment under natural pH conditions, but it enhanced the nitrogen removal in the electro-Fenton assays performed at an initial pH of 3. The combined anodic oxidation and electro-Fenton process is useful for treating the reverse osmosis concentrate because it is effective at removing the organic load and nitrogen-containing species. Additionally, this process potentiates the increase in the biodegradability index of the treated effluent. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation of black liquor from bioethanol process using coagulation and Fenton-like methods

NASA Astrophysics Data System (ADS)

Muryanto, Muryanto; Sari, Ajeng Arum; Abimanyu, Haznan

2017-01-01

Black liquor is one of the main by-products of the pretreatment process in bioethanol production from oil palm empty fruit bunches. Black liquor wastewater releases black coloured effluent with high chemical oxygen demand (COD) and low dissolved oxygen (DO). It had a distinctive dark coloration, high alkalinity (pH=13), high organic content (COD > 50,000 ppm) and a high solid content (TSS > 5,000 ppm). Lignin destruction can be done by using high oxidation from OH radical system such as advanced oxidation processes (AOPs). Thereafter, the high concentration of COD, color, and TSS can be removed. The general aim of the present investigation was to determine degradation of black liquor wastewater by using a combined coagulation and Fenton-like methods. In this research, we use Poly Aluminum Chloride (PAC) as a coagulant and FeCl3.6H2O and H2O2 for Fenton-like's reagent. The process was conducted in jar test at 200 rpm for 30 minutes and after that slowly mixed for 2 hours and left for sedimentation 24 hours. 50 ml black liquor was added with variation dose of 1-5% PAC, and 10 % Fenton-like reagent. Hydroxyl radical was generated by the Fenton-like's reagent (ratio FeCl3.6H2O : H2O2 was varied). The highest decolorization of black liquor 70 % was obtained under 5% PAC coagulant. The pH of the wastewater was reduced from 13.00 to 8.07 after the addition of the coagulant. The decolorization of original black liquor was approximately 58% through the Fenton-like process. The combination of PAC and Fenton-like reagent has able to enhance the decolorization of black liquor up to 97%.

Relationship between reaction rate constants of organic pollutants and their molecular descriptors during Fenton oxidation and in situ formed ferric-oxyhydroxides.

PubMed

Jia, Lijuan; Shen, Zhemin; Su, Pingru

2016-05-01

Fenton oxidation is a promising water treatment method to degrade organic pollutants. In this study, 30 different organic compounds were selected and their reaction rate constants (k) were determined for the Fenton oxidation process. Gaussian09 and Material Studio software sets were used to carry out calculations and obtain values of 10 different molecular descriptors for each studied compound. Ferric-oxyhydroxide coagulation experiments were conducted to determine the coagulation percentage. Based upon the adsorption capacity, all of the investigated organic compounds were divided into two groups (Group A and Group B). The percentage adsorption of organic compounds in Group A was less than 15% (wt./wt.) and that in the Group B was higher than 15% (wt./wt.). For Group A, removal of the compounds by oxidation was the dominant process while for Group B, removal by both oxidation and coagulation (as a synergistic process) took place. Results showed that the relationship between the rate constants (k values) and the molecular descriptors of Group A was more pronounced than for Group B compounds. For the oxidation-dominated process, EHOMO and Fukui indices (f(0)x, f(-)x, f(+)x) were the most significant factors. The influence of bond order was more significant for the synergistic process of oxidation and coagulation than for the oxidation-dominated process. The influences of all other molecular descriptors on the synergistic process were weaker than on the oxidation-dominated process. Copyright © 2015. Published by Elsevier B.V.

Application of Fenton oxidation to cosmetic wastewaters treatment.

PubMed

Bautista, P; Mohedano, A F; Gilarranz, M A; Casas, J A; Rodriguez, J J

2007-05-08

The removal of organic matter (TOC and COD) from a cosmetic wastewater by Fenton oxidation treatment has been evaluated. The operating conditions (temperature as well as ferrous ion and hydrogen peroxide dosage) have been optimized. Working at an initial pH equal to 3.0, a Fe(2+) concentration of 200 mg/L and a H(2)O(2) concentration to COD initial weight ratio corresponding to the theoretical stoichiometric value (2.12), a TOC conversion higher than 45% at 25 degrees C and 60% at 50 degrees C was achieved. Application of the Fenton oxidation process allows to reach the COD regional limit for industrial wastewaters discharges to the municipal sewer system. A simple kinetic analysis based on TOC was carried out. A second-order equation describes well the overall kinetics of the process within a wide TOC conversion range covering up to the 80-90% of the maximum achievable conversion.

Degradation mechanism of Direct Pink 12B treated by iron-carbon micro-electrolysis and Fenton reaction.

PubMed

Wang, Xiquan; Gong, Xiaokang; Zhang, Qiuxia; Du, Haijuan

2013-12-01

The Direct Pink 12B dye was treated by iron-carbon micro-electrolysis (ICME) and Fenton oxidation. The degradation pathway of Direct Pink 12B dye was inferred by ultraviolet visible (UV-Vis), infrared absorption spectrum (IR) and high performance liquid chromatography-mass spectrometry (HPLC-MS). The major reason of decolorization was that the conjugate structure was disrupted in the iron-carbon micro-electrolysis (ICME) process. However, the dye was not degraded completely because benzene rings and naphthalene rings were not broken. In the Fenton oxidation process, the azo bond groups surrounded by higher electron cloud density were first attacked by hydroxyl radicals to decolorize the dye molecule. Finally benzene rings and naphthalene rings were mineralized to H2O and CO2 under the oxidation of hydroxyl radicals. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Wastewater treatment using hybrid treatment schemes based on cavitation and Fenton chemistry: a review.

PubMed

Bagal, Manisha V; Gogate, Parag R

2014-01-01

Advanced oxidation processes such as cavitation and Fenton chemistry have shown considerable promise for wastewater treatment applications due to the ease of operation and simple reactor design. In this review, hybrid methods based on cavitation coupled with Fenton process for the treatment of wastewater have been discussed. The basics of individual processes (Acoustic cavitation, Hydrodynamic cavitation, Fenton chemistry) have been discussed initially highlighting the need for combined processes. The different types of reactors used for the combined processes have been discussed with some recommendations for large scale operation. The effects of important operating parameters such as solution temperature, initial pH, initial pollutant concentration and Fenton's reagent dosage have been discussed with guidelines for selection of optimum parameters. The optimization of power density is necessary for ultrasonic processes (US) and combined processes (US/Fenton) whereas the inlet pressure needs to be optimized in the case of Hydrodynamic cavitation (HC) based processes. An overview of different pollutants degraded under optimized conditions using HC/Fenton and US/Fenton process with comparison with individual processes have been presented. It has been observed that the main mechanism for the synergy of the combined process depends on the generation of additional hydroxyl radicals and its proper utilization for the degradation of the pollutant, which is strongly dependent on the loading of hydrogen peroxide. Overall, efficient wastewater treatment with high degree of energy efficiency can be achieved using combined process operating under optimized conditions, as compared to the individual process. Copyright © 2013 Elsevier B.V. All rights reserved.

PAEs and BPA removal in landfill leachate with Fenton process and its relationship with leachate DOM composition.

PubMed

He, Pin-Jing; Zheng, Zhong; Zhang, Hua; Shao, Li-Ming; Tang, Qiong-Yao

2009-08-15

An increasing attention has been paid to the trace endocrine disrupting compounds (EDCs) in landfill leachate. In this paper, the removal of EDCs including phthalic acid esters (PAEs) and bisphenol A (BPA) from the fresh and mature landfill leachate by Fenton treatment was studied. More than 40% of PAEs and about 62% of BPA were removed from the raw mature leachate while only 20% of PAEs and 37% of BPA in the raw fresh leachate were reduced, respectively. After the fresh and mature leachates were spiked with PAEs to 1.5 mg L(-1) and BPA to 0.08 mg L(-1), the removal efficiencies of BPA and PAEs increased to more than 88%. The results indicated that the removing efficiencies of the EDCs in the leachate had a relationship with their concentrations, and that the trace levels of EDCs in leachate challenged the treatment capacity of the Fenton process. Most of the EDCs in the enriched leachate were removed by oxidation, which had no clear correlation with the hydrophobicity of the EDCs. The flocculation played an important role in the removal of di-(2-ethylhexyl) phthalate that could not be completely oxidized in the Fenton process, in that the EDCs with high n-octanol/water partition coefficient inclined to precipitate after the Fenton process. The dissolved organic matter (DOM) in the fresh leachate inhibited the EDCs removal more than the DOM in the mature leachate did. Both the composition of the leachate DOM and the characteristics of the EDCs determined the removing efficiencies of the EDCs in the Fenton process.

Reactivity of catecholamine-driven Fenton reaction and its relationships with iron(III) speciation.

PubMed

Melin, Victoria; Henríquez, Adolfo; Freer, Juanita; Contreras, David

2015-03-01

Fenton reaction is the main source of free radicals in biological systems. The reactivity of this reaction can be modified by several factors, among these iron ligands are important. Catecholamine (dopamine, epinephrine, and norepinephrine) are able to form Fe(III) complexes whose extension in the coordination number depends upon the pH. Fe(III)-catecholamine complexes have been related with the development of several pathologies. In this work, the ability of catecholamines to enhance the oxidative degradation of an organic substrate (veratryl alcohol, VA) through Fenton and Fenton-like reactions was studied. The initial VA degradation rate at different pH values and its relationship to the different iron species present in solution were determined. Furthermore, the oxidative degradation of VA after 24 hours of reaction and its main oxidation products were also determined. The catecholamine-driven Fenton and Fenton-like systems showed higher VA degradation compared to unmodified Fenton or Fenton-like systems, which also showed an increase in the oxidation state of the VA degradation product. All of this oxidative degradation takes place at pH values lower than 5.50, where the primarily responsible species would be the Fe(III) mono-complex. The presence of Fe(III) mono-complex is essential in the ability of catecholamines to increase the oxidative capacity of Fenton systems.

DEGRADATION OF MTBE INTERMEDIATES USING FENTON'S REAGENT

EPA Science Inventory

In a previous study, the chemical oxidation of MTBE at low concentrations in water using the Fenton's reagent (FR) was investigated. At certain reaction conditions the process achieved 99.99% degradation of MTBE but it did not result in complete MTBE mineralization. In the pres...

Heterogeneous electro-Fenton catalyst for 1-butylpyridinium chloride degradation.

PubMed

Meijide, Jessica; Pazos, Marta; Sanromán, Maria Ángeles

2017-10-15

The application of the electro-Fenton process for organic compound mineralisation has been widely reported over the past years. However, operational problems related to the use of soluble iron salt as a homogeneous catalyst involve the development of novel catalysts that are able to operate in a wide pH range. For this purpose, polyvinyl alcohol-alginate beads, containing goethite as iron, were synthesised and evaluated as heterogeneous electro-Fenton catalyst for 1-butylpyridinium chloride mineralisation. The influence of catalyst dosage and pH solution on ionic liquid degradation was analysed, achieving almost total oxidation after 60 min under optimal conditions (2 g/L catalyst concentration and pH 3). The results showed good catalyst stability and reusability, although its effectiveness decreases slightly after three successive cycles. Furthermore, a plausible mineralisation pathway was proposed based on the oxidation byproducts determined by chromatographic techniques. Finally, the Microtox® test revealed notable detoxification after treatment which demonstrates high catalyst ability for pyridinium-based ionic liquid degradation by the electro-Fenton process.

Self-Propelled Micromotors for Cleaning Polluted Water

PubMed Central

2013-01-01

We describe the use of catalytically self-propelled microjets (dubbed micromotors) for degrading organic pollutants in water via the Fenton oxidation process. The tubular micromotors are composed of rolled-up functional nanomembranes consisting of Fe/Pt bilayers. The micromotors contain double functionality within their architecture, i.e., the inner Pt for the self-propulsion and the outer Fe for the in situ generation of ferrous ions boosting the remediation of contaminated water.The degradation of organic pollutants takes place in the presence of hydrogen peroxide, which acts as a reagent for the Fenton reaction and as main fuel to propel the micromotors. Factors influencing the efficiency of the Fenton oxidation process, including thickness of the Fe layer, pH, and concentration of hydrogen peroxide, are investigated. The ability of these catalytically self-propelled micromotors to improve intermixing in liquids results in the removal of organic pollutants ca. 12 times faster than when the Fenton oxidation process is carried out without catalytically active micromotors. The enhanced reaction–diffusion provided by micromotors has been theoretically modeled. The synergy between the internal and external functionalities of the micromotors, without the need of further functionalization, results into an enhanced degradation of nonbiodegradable and dangerous organic pollutants at small-scale environments and holds considerable promise for the remediation of contaminated water. PMID:24180623

Mineralization enhancement of a recalcitrant pharmaceutical pollutant in water by advanced oxidation hybrid processes.

PubMed

Méndez-Arriaga, F; Torres-Palma, R A; Pétrier, C; Esplugas, S; Gimenez, J; Pulgarin, C

2009-09-01

Degradation of the biorecalcitrant pharmaceutical micropollutant ibuprofen (IBP) was carried out by means of several advanced oxidation hybrid configurations. TiO(2) photocatalysis, photo-Fenton and sonolysis - all of them under solar simulated illumination - were tested in the hybrid systems: sonophoto-Fenton (FS), sonophotocatalysis (TS) and TiO(2)/Fe(2+)/sonolysis (TFS). In the case of the sonophoto-Fenton process, the IBP degradation (95%) and mineralization (60%) were attained with photo-Fenton (FH). The presence of ultrasonic irradiation slightly improves the iron catalytic activity. On the other hand, total removal of IBP and elimination of more than 50% of dissolved organic carbon (DOC) were observed by photocatalysis with TiO(2) in the presence of ultrasound irradiation (TS). In contrast only 26% of mineralization was observed by photocatalysis with H(2)O(2) (TH) in the absence of ultrasound irradiation. Additional results showed that, in the TFS system, 92% of DOC removal and complete degradation of IBP were obtained within 240 min of treatment. The advanced oxidation hybrid systems seems to be a promising alternative for full elimination/mineralization for the recalcitrant micro-contaminant IBP.

Drinking water and biofilm disinfection by Fenton-like reaction.

PubMed

Gosselin, F; Madeira, L M; Juhna, T; Block, J C

2013-10-01

A Fenton-like disinfection process was conducted with Fenton's reagent (H2O2) at pH 3 or 5 on autochthonous drinking water biofilms grown on corroded or non-corroded pipe material. The biofilm disinfection by Fenton-like oxidation was limited by the low content of iron and copper in the biomass grown on non-corroded plumbing. It was slightly improved by spiking the distribution system with some additional iron source (soluble iron II or ferrihydrite particles appeared as interesting candidates). However successful in situ disinfection of biofilms was only achieved in fully corroded cast iron pipes using H2O2 and adjusting the pH to 5. These new results provide additional support for the use of Fenton's processes for cleaning drinking water distribution systems contaminated with biological agents or organics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fe0 catalyzed photo-Fenton process to detoxify the biodegraded products of azo dye Mordant Yellow 10.

PubMed

Brindha, R; Muthuselvam, P; Senthilkumar, S; Rajaguru, P

2018-06-01

Inspired by the efficiency of the photo-Fenton process on oxidation of organic pollutants, we herein present the feasibility of visible light driven photo-Fenton process as a post treatment of biological method for the effective degradation and detoxification of monoazo dye Mordant Yellow 10 (MY10). Anaerobic degradation of MY10 by Pseudomonas aeroginosa formed aromatic amines which were further degraded in the subsequent Fe catalyzed photo-Fenton process carried out at pH 3.0, with iron shavings and H 2 O 2 under blue LED light illumination. LC-MS and stoichiometric analysis confirmed that reductive azo bond cleavage was the major reaction in anaerobic bacterial degradation of MY10 producing 4-amino benzene sulfonic acid (4-ABS) and 5-amino salicylic acid (5-ASA) which were further degraded into hydroxyl amines, nitroso and di/tri carboxylic acids by the photo-Fenton process. Toxicity studies with human small cell lung cancer A549 cells provide evidence that incorporation of Fe 0 catalyzed photo-Fenton step after anaerobic bacterial treatment improved the mineralization and detoxification of MY10 dye. Copyright © 2018 Elsevier Ltd. All rights reserved.

Incorporation of electrochemical advanced oxidation processes in a multistage treatment system for sanitary landfill leachate.

PubMed

Moreira, Francisca C; Soler, J; Fonseca, Amélia; Saraiva, Isabel; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

2015-09-15

The current study has proved the technical feasibility of including electrochemical advanced oxidation processes (EAOPs) in a multistage strategy for the remediation of a sanitary landfill leachate that embraced: (i) first biological treatment to remove the biodegradable organic fraction, oxidize ammonium and reduce alkalinity, (ii) coagulation of the bio-treated leachate to precipitate humic acids and particles, followed by separation of the clarified effluent, and (iii) oxidation of the resulting effluent by an EAOP to degrade the recalcitrant organic matter and increase its biodegradability so that a second biological process for removal of biodegradable organics and nitrogen content could be applied. The influence of current density on an UVA photoelectro-Fenton (PEF) process was firstly assessed. The oxidation ability of various EAOPs such as electro-Fenton (EF) with two distinct initial total dissolved iron concentrations ([TDI]0), PEF and solar PEF (SPEF) was further evaluated and these processes were compared with their analogous chemical ones. A detailed assessment of the two first treatment stages was made and the biodegradability enhancement during the SPEF process was determined by a Zahn-Wellens test to define the ideal organics oxidation state to stop the EAOP and apply the second biological treatment. The best current density was 200 mA cm(-2) for a PEF process using a BDD anode, [TDI]0 of 60 mg L(-1), pH 2.8 and 20 °C. The relative oxidation ability of EAOPs increased in the order EF with 12 mg [TDI]0 L(-1) < EF with 60 mg [TDI]0 L(-1) < PEF with 60 mg [TDI]0 L(-1) ≤ SPEF with 60 mg [TDI]0 L(-1), using the abovementioned conditions. While EF process was much superior to the Fenton one, the superiority of PEF over photo-Fenton was less evident and SPEF attained similar degradation to solar photo-Fenton. To provide a final dissolved organic carbon (DOC) of 163 mg L(-1) to fulfill the discharge limits into the environment after a second biological process, 6.2 kJ L(-1) UV energy and 36 kWh m(-3) electrical energy were consumed using SPEF with a BDD anode at 200 mA cm(-2), 60 mg [TDI]0 L(-1), pH 2.8 and 20 °C. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparative study for degradation of industrial dyes by electrochemical advanced oxidation processes with BDD anode in a laboratory stirred tank reactor.

PubMed

Alcocer, Salvador; Picos, Alain; Uribe, Agustín R; Pérez, Tzayam; Peralta-Hernández, Juan M

2018-08-01

Comparative degradation of the industrial dyes Blue BR, Violet SBL and Brown MF 50 mg L -1 has been studied by the electrochemical oxidation (EOx), electro-Fenton (EF), photoelectro-Fenton (PEF) process based on BDD electrode. Each dye was tested in 0.05 mM Na 2 SO 4 with 0.5 mM Fe 2+ at pH 3.0, and electrolyzed in a stirred tank reactor under galvanostatic conditions with 2.0, 5.0, 7.0, 11.0 and 18.0 mA cm -2 . Dyes were oxidized via hydroxyl radicals (OH) formed at the BDD anode from water oxidation coupled with Fenton's reaction cathodically produced hydrogen peroxide (H 2 O 2 ). Under Na 2 SO 4 medium close to 100% the decolorization was achieved. Through the color abatement rate the dyes behavior was analyzed at the beginning of the oxidation process. Dissolved Organic Carbon (DOC) was tested to evaluate the degradation. From DOC removal, it was established an increasing relative oxidation power of the EOx < EF < PEF, according with their decolorization trend. This study highlights the potential of the electrochemical/BDD process for the degradation of industrial dyes found in wastewaters under appropriate experimental conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Degradation of clofibric acid in acidic aqueous medium by electro-Fenton and photoelectro-Fenton.

PubMed

Sirés, Ignasi; Arias, Conchita; Cabot, Pere Lluís; Centellas, Francesc; Garrido, José Antonio; Rodríguez, Rosa María; Brillas, Enric

2007-01-01

Acidic aqueous solutions of clofibric acid (2-(4-chlorophenoxy)-2-methylpropionic acid), the bioactive metabolite of various lipid-regulating drugs, have been degraded by indirect electrooxidation methods such as electro-Fenton and photoelectro-Fenton with Fe(2+) as catalyst using an undivided electrolytic cell with a Pt anode and an O(2)-diffusion cathode able to electrogenerate H(2)O(2). At pH 3.0 about 80% of mineralization is achieved with the electro-Fenton method due to the efficient production of oxidant hydroxyl radical from Fenton's reaction between Fe(2+) and H(2)O(2), but stable Fe(3+) complexes are formed. The photoelectro-Fenton method favors the photodecomposition of these species under UVA irradiation, reaching more than 96% of decontamination. The mineralization current efficiency increases with rising metabolite concentration up to saturation and with decreasing current density. The photoelectro-Fenton method is then viable for treating acidic wastewaters containing this pollutant. Comparative degradation by anodic oxidation (without Fe(2+)) yields poor decontamination. Chloride ion is released during all degradation processes. The decay kinetics of clofibric acid always follows a pseudo-first-order reaction, with a similar rate constant in electro-Fenton and photoelectro-Fenton that increases with rising current density, but decreases at greater metabolite concentration. 4-Chlorophenol, 4-chlorocatechol, 4-chlororesorcinol, hydroquinone, p-benzoquinone and 1,2,4-benzenetriol, along with carboxylic acids such as 2-hydroxyisobutyric, tartronic, maleic, fumaric, formic and oxalic, are detected as intermediates. The ultimate product is oxalic acid, which forms very stable Fe(3+)-oxalato complexes under electro-Fenton conditions. These complexes are efficiently photodecarboxylated in photoelectro-Fenton under the action of UVA light.

IRON OPTIMIZATION FOR FENTON-DRIVEN OXIDATION OF MTBE-SPENT GRANULAR ACTIVATED CARBON

EPA Science Inventory

Fenton-driven chemical regeneration of granular activated carbon (GAC) is accomplished through the addition of H2O2 and iron (Fe) to spent GAC. The overall objective of this treatment process is to transform target contaminants into less toxic byproducts, re-establish the sorpti...

Comprehensive study on effects of water matrices on removal of pharmaceuticals by three different kinds of advanced oxidation processes.

PubMed

Tokumura, Masahiro; Sugawara, Asato; Raknuzzaman, Mohammad; Habibullah-Al-Mamun, Md; Masunaga, Shigeki

2016-09-01

Simple semi-theoretical models were developed to estimate the performance of three different kinds of advanced oxidation processes (AOPs) in the degradation of pharmaceuticals. The AOPs included the photo-Fenton process as an example of a liquid-liquid reaction, the TiO2 photocatalytic oxidation process as a solid-liquid reaction, and the combined ozone and hydrogen peroxide oxidation process as a gas-liquid reaction; the effects of the aqueous matrices (CESs: co-existing substances) of actual wastewater on the removal of pharmaceuticals (carbamazepine and diclofenac) was taken into account. By comparing the characteristic parameters of the models, obtained from the experiments using pure water and actual wastewater, the effects of CESs on the respective removal mechanisms could be separately and quantitatively evaluated. As a general tendency, the AOPs proceeded less effectively (were inhibited) in the matrices containing CESs, as observed with the use of a lower initial concentration of pharmaceuticals. The inhibition mechanisms differed for the three types of AOPs. In the photo-Fenton process, the Fenton reaction was improved by the incorporation of CESs, while the photo-reduction reaction was significantly inhibited. In the TiO2 photocatalytic oxidation process, competition between the pharmaceuticals and CESs for adsorption on the catalyst surface was a less significant inhibitory factor than the scavenger effects of the CESs. The combined ozone and hydrogen peroxide oxidation process was most strongly inhibited by CESs among the AOPs investigated in this study. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of hazardous landfill leachate using Fenton process followed by a combined (UASB/DHS) system.

PubMed

Ismail, Sherif; Tawfik, Ahmed

2016-01-01

Fenton process for pre-treatment of hazardous landfill leachate (HLL) was investigated. Total, particulate and soluble chemical oxygen demand (CODt, CODp and CODs) removal efficiency amounted to 67%, 47% and 64%, respectively, at pH value of 3.5, molar ratio (H2O2/Fe(2+)) of 5, H2O2 dosage of 25 ml/L and contact time of 15 min. Various treatment scenarios were attempted and focused on studying the effect of pre-catalytic oxidation process on the performance of up-flow anaerobic sludge blanket (UASB), UASB/down-flow hanging sponge (DHS) and DHS system. The results obtained indicated that pre-catalytic oxidation process improved the CODt removal efficiency in the UASB reactor by a value of 51.4%. Overall removal efficiencies of CODt, CODs and CODp were 80 ± 6%, 80 ± 7% and 78 ± 16% for UASB/DHS treating pre-catalytic oxidation effluent, respectively. The removal efficiencies of CODt, CODs and CODp were, respectively, decreased to 54 ± 2%, 49 ± 2% and 71 ± 16% for UASB/DHS system without pre-treatment. However, the results for the combined process (UASB/DHS) system is almost similar to those obtained for UASB reactor treating pre-catalytic oxidation effluent. The DHS system achieved average removal efficiencies of 52 ± 4% for CODt, 51 ± 4% for CODs and 52 ± 15% for CODp. A higher COD fractions removal was obtained when HLL was pre-treated by Fenton reagent. The combined processes provided a removal efficiency of 85 ± 1% for CODt, 85 ± 1% for CODs and 83 ± 8% for CODp. The DHS system is not only effective for organics degradation but also for ammonia oxidation. Almost complete ammonia (NH4-N) removal (92 ± 3.6%) was occurred and the nitrate production amounted to 37 ± 6 mg/L in the treated effluent. This study strongly recommends applying Fenton process followed by DHS system for treatment of HLL.

Removal of antibiotic cloxacillin by means of electrochemical oxidation, TiO2 photocatalysis, and photo-Fenton processes: analysis of degradation pathways and effect of the water matrix on the elimination of antimicrobial activity.

PubMed

Serna-Galvis, Efraim A; Giraldo-Aguirre, Ana L; Silva-Agredo, Javier; Flórez-Acosta, Oscar A; Torres-Palma, Ricardo A

2017-03-01

This study evaluates the treatment of the antibiotic cloxacillin (CLX) in water by means of electrochemical oxidation, TiO 2 photocatalysis, and the photo-Fenton system. The three treatments completely removed cloxacillin and eliminated the residual antimicrobial activity from synthetic pharmaceutical wastewater containing the antibiotic, commercial excipients, and inorganic ions. However, significant differences in the degradation routes were found. In the photo-Fenton process, the hydroxyl radical was involved in the antibiotic removal, while in the TiO 2 photocatalysis process, the action of both the holes and the adsorbed hydroxyl radicals degraded the pollutant. In the electrochemical treatment (using a Ti/IrO 2 anode in sodium chloride as supporting electrolyte), oxidation via HClO played the main role in the removal of CLX. The analysis of initial by-products showed five different mechanistic pathways: oxidation of the thioether group, opening of the central β-lactam ring, breakdown of the secondary amide, hydroxylation of the aromatic ring, and decarboxylation. All the oxidation processes exhibited the three first pathways. Moreover, the aromatic ring hydroxylation was found in both photochemical treatments, while the decarboxylation of the pollutant was only observed in the TiO 2 photocatalysis process. As a consequence of the degradation routes and mechanistic pathways, the elimination of organic carbon was different. After 480 and 240 min, the TiO 2 photocatalysis and photo-Fenton processes achieved ∼45 and ∼15 % of mineralization, respectively. During the electrochemical treatment, 100 % of the organic carbon remained even after the antibiotic was treated four times the time needed to degrade it. In contrast, in all processes, a natural matrix (mineral water) did not considerably inhibit pollutant elimination. However, the presence of glucose in the water significantly affected the degradation of CLX by means of TiO 2 photocatalysis.

Experimental Study on Treatment of Dyeing Wastewater by Activated Carbon Adsorption, Coagulation and Fenton Oxidation

NASA Astrophysics Data System (ADS)

Xiaoxu, SUN; Jin, XU; Xingyu, LI

2017-12-01

In this paper dyeing waste water was simulated by reactive brilliant blue XBR, activated carbon adsorption process, coagulation process and chemical oxidation process were used to treat dyeing waste water. In activated carbon adsorption process and coagulation process, the water absorbance values were measured. The CODcr value of water was determined in Fenton chemical oxidation process. Then, the decolorization rate and COD removal rate were calculated respectively. The results showed that the optimum conditions of activated carbon adsorption process were as follows: pH=2, the dosage of activated carbon was 1.2g/L, the adsorption reaction time was 60 min, and the average decolorization rate of the three parallel experiments was 85.30%. The optimum conditions of coagulation experiment were as follows: pH=8~9, PAC dosage was 70mg/L, stirring time was 20min, standing time was 45min, the average decolorization rate of the three parallel experiments was 74.48%. The optimum conditions for Fenton oxidation were Fe2+ 0.05g/L, H2O2 (30%) 14mL/L, pH=3, reaction time 40min. The average CODcr removal rate was 69.35% in three parallel experiments. It can be seen that in the three methods the activated carbon adsorption treatment of dyeing wastewater was the best one.

Feasibility of bioleaching combined with Fenton oxidation to improve sewage sludge dewaterability.

PubMed

Liu, Changgeng; Zhang, Panyue; Zeng, Chenghua; Zeng, Guangming; Xu, Guoyin; Huang, Yi

2015-02-01

A novel joint method of bioleaching with Fenton oxidation was applied to condition sewage sludge. The specific resistance to filtration (SRF) and moisture of sludge cake (MSC) were adopted to evaluate the improvement of sludge dewaterability. After 2-day bioleaching, the sludge pH dropped to about 2.5 which satisfied the acidic condition for Fenton oxidation. Meanwhile, the SRF declined from 6.45×10(10) to 2.07×10(10) s2/g, and MSC decreased from 91.42% to 87.66%. The bioleached sludge was further conditioned with Fenton oxidation. From an economical point of view, the optimal dosages of H2O2 and Fe2+ were 0.12 and 0.036 mol/L, respectively, and the optimal reaction time was 60 min. Under optimal conditions, SRF, volatile solids reduction, and MSC were 3.43×10(8) s2/g, 36.93%, and 79.58%, respectively. The stability and settleability of sewage sludge were both improved significantly. Besides, the results indicated that bioleaching-Fenton oxidation was more efficient in dewatering the sewage sludge than traditional Fenton oxidation. The sludge conditioning mechanisms by bioleaching-Fenton oxidation might mainly include the flocculation effects and the releases of extracellular polymeric substances-bound water and intercellular water. Copyright © 2014. Published by Elsevier B.V.

Photo-assisted electrochemical degradation of polychlorinated biphenyls with boron-doped diamond electrodes.

PubMed

Gutiérrez-Hernández, Rubén F; Bello-Mendoza, Ricardo; Hernández-Ramírez, Aracely; Malo, Edi A; Nájera-Aguilar, Hugo A

2017-09-19

The capacity of the photo electro-Fenton (PEF) process to degrade a mixture of seven polychlorinated biphenyl (PCB) congeners was studied. Boron-doped diamond (BDD) sheets were used as anode and cathode in the experimental electrolytic cell that contained Na 2 SO 4 0.05 M at pH 3 as supporting electrolyte for the electro generation of H 2 O 2 at the cathode. The effects of UV light intensity (254 and 365 nm), current density (8, 16 and 24 mA cm -2 ) and ferrous ion dosage (0.1, 0.2 and 0.3 mM) on PCB (C 0 = 50 μg L -1 ) degradation were evaluated. The highest level of PCB degradation (97%) was achieved with 16 mA cm -2 of current density, 0.1 mM of ferrous ion and UV light at 365 nm as irradiation source after 6 h of reaction. PCB28, PCB52 and PCB101 were not detected after 0.5, 1.5 and 3 h of reaction, respectively. The degradation of PCB138, PCB153, PCB180 and PCB209 was also high (>95%). The PEF system outperformed other oxidation processes (electro-Fenton, anodic oxidation, Fenton, photo-Fenton and UV photolysis) in terms of reaction rate and degradation efficiency. These results demonstrate for the first time the degradation of PCB209, the most highly chlorinated PCB congener, by an advanced electrochemical oxidation process.

Comparison of different wastewater treatments for removal of selected endocrine-disruptors from paper mill wastewaters.

PubMed

Balabanič, Damjan; Hermosilla, Daphne; Merayo, Noemí; Klemenčič, Aleksandra Krivograd; Blanco, Angeles

2012-01-01

There is increasing concern about chemical pollutants that have the ability to mimic hormones, the so-called endocrine-disrupting compounds (EDCs). One of the main reasons for concern is the possible effect of EDCs on human health. EDCs may be released into the environment in different ways, and one of the most significant sources is industrial wastewater. The main objective of this research was to evaluate the treatment performance of different wastewater treatment procedures (biological treatment, filtration, advanced oxidation processes) for the reduction of chemical oxygen demand and seven selected EDCs (dimethyl phthalate, diethyl phthalate, dibutyl phthalate, benzyl butyl phthalate, bis(2-ethylhexyl) phthalate, bisphenol A and nonylphenol) from wastewaters from a mill producing 100 % recycled paper. Two pilot plants were running in parallel and the following treatments were compared: (i) anaerobic biological treatment followed by aerobic biological treatment, ultrafiltration and reverse osmosis (RO), and (ii) anaerobic biological treatment followed by membrane bioreactor and RO. Moreover, at lab-scale, four different advanced oxidation processes (Fenton reaction, photo-Fenton reaction, photocatalysis with TiO(2), and ozonation) were applied. The results indicated that the concentrations of selected EDCs from paper mill wastewaters were effectively reduced (100 %) by both combinations of pilot plants and photo-Fenton oxidation (98 %), while Fenton process, photocatalysis with TiO(2) and ozonation were less effective (70 % to 90 %, respectively).

Regeneration and reuse of iron catalyst for Fenton-like reactions.

PubMed

Cao, Guo-min; Sheng, Mei; Niu, Wen-feng; Fei, Yu-lei; Li, Dong

2009-12-30

Fenton and Fenton-like reactions employed for oxidative treatment of a typical industrial wastewater generate a large amount of ferric hydroxide sludge which has to be properly disposed at a high cost. This paper presents a simple and cost-effective method for recovering the iron catalyst from the iron hydroxide sludge for oxidative treatment of industrial wastewaters. The sludge was dewatered, dried and baked at 350-400 degrees C for 20-30 min; the residual solids were dissolved in sulfuric acid to form the reusable catalyst for Fenton and Fenton-like reactions. The recovered catalyst was highly effective for the oxidative pretreatment of a fine chemical wastewater to improve its biodegradability; the resulting COD removal and BOD(5)/COD ratio of the treated stream remained nearly unchanged during the time period when the regenerated catalyst was reused six times. The simple and effective catalyst regeneration method will make Fenton and Fenton-like oxidation a more cost-effective wastewater treatment alternative.

CONTAMINANT ADSORPTION AND OXIDATION VIA FENTON REACTION

EPA Science Inventory

A ground water treatment process is proposed involving two cgemical processes: adsorption and oxidation. Adsorption of an organic compound onto granulated activated carbon (GAC) containing iron conveniently results in immobilizing and concentrating contaminants from the ground w...

The study of a pilot-scale aerobic/Fenton/anoxic/aerobic process system for the treatment of landfill leachate.

PubMed

Hu, Wenyong; Zhou, Yu; Min, Xiaobo; Liu, Jingyi; Li, Xinyu; Luo, Lin; Zhang, Jiachao; Mao, Qiming; Chai, Liyuan; Zhou, YaoYu

2017-06-29

In this study, a combined aerobic-Fenton-anoxic/aerobic system was designed for the remediation of raw landfill leachate in a pilot-scale experiment. This system included (i) a granular sludge biological oxidation procedure that achieves the accumulation of nitrite nitrogen ([Formula: see text]) under aerobic conditions; (ii) a Fenton process that improves the biodegradability of the biotreated leachate and (iii) an activated sludge biological oxidation component under anoxic and aerobic conditions. Additionally, a shortcut nitrification and denitrification pathway was achieved. The effects of free ammonia, temperature and pH on nitrite accumulation were discussed. The change in the biochemical oxygen demand/chemical oxygen demand ratio of the effluent after shortcut nitrification was also analysed. The microbial community in the reactor were also investigated. The problem of the lack of carbon source in the denitrification process can be solved by the Fenton reagent method. Moreover, it was beneficial to achieving nitrogen removal as well as the more extensive removal of organic matter. The treatment strategy employed in this study exhibited good results and provided the potential practical application for treating landfill leachate.

Electrochemical advanced oxidation processes: today and tomorrow. A review.

PubMed

Sirés, Ignasi; Brillas, Enric; Oturan, Mehmet A; Rodrigo, Manuel A; Panizza, Marco

2014-01-01

In recent years, new advanced oxidation processes based on the electrochemical technology, the so-called electrochemical advanced oxidation processes (EAOPs), have been developed for the prevention and remediation of environmental pollution, especially focusing on water streams. These methods are based on the electrochemical generation of a very powerful oxidizing agent, such as the hydroxyl radical ((•)OH) in solution, which is then able to destroy organics up to their mineralization. EAOPs include heterogeneous processes like anodic oxidation and photoelectrocatalysis methods, in which (•)OH are generated at the anode surface either electrochemically or photochemically, and homogeneous processes like electro-Fenton, photoelectro-Fenton, and sonoelectrolysis, in which (•)OH are produced in the bulk solution. This paper presents a general overview of the application of EAOPs on the removal of aqueous organic pollutants, first reviewing the most recent works and then looking to the future. A global perspective on the fundamentals and experimental setups is offered, and laboratory-scale and pilot-scale experiments are examined and discussed.

Effective removal of the antibiotic Nafcillin from water by combining the Photoelectro-Fenton process and Anaerobic Biological Digestion.

PubMed

Vidal, Jorge; Huiliñir, Cesar; Santander, Rocío; Silva-Agredo, Javier; Torres-Palma, Ricardo A; Salazar, Ricardo

2018-05-15

The elimination of the antibiotic Nafcillin (NAF), which is usually used in hospitals and veterinary clinics around the world, was assessed through a combination of three advanced electrochemical oxidation processes followed by anaerobic digestion process. In the first stage different electrochemical advanced oxidation processes (EAOPs) were used: electro-oxidation with hydrogen peroxide (EO-H 2 O 2 ), electro-Fenton (EF) and Photo electro-Fenton (PEF). After PEF, almost complete and highly efficient degradation and elimination of NAF was achieved, with the concomitant elimination of the associated antimicrobial activity. The fast degradation rate produced by PEF is explained by the oxidative action of hydroxyl radicals (•OH) together with the direct UV photolysis of complexes formed between Fe 3+ and some organic intermediates. Total removal of NAF occurs after 90min of electrolysis by PEF, with the generation of organic intermediates that remain in solution. However, when this post PEF process solution was treated with an anaerobic biological process, the intermediates generated in the electrochemical degradation of NAF were completely eliminated after 24h. The kinetic degradation of NAF as well as the identification/quantification of products and intermediates formed during the degradation of antibiotic, such as inorganic ions, carboxylic acids and aromatic compounds, were determined by chromatographic and photometric methods. Finally, an oxidation pathway is proposed for the complete conversion to CO 2 . Copyright © 2017 Elsevier B.V. All rights reserved.

Recovery of microbial diversity and activity during bioremediation following chemical oxidation of diesel contaminated soils.

PubMed

Sutton, Nora B; Langenhoff, Alette A M; Lasso, Daniel Hidalgo; van der Zaan, Bas; van Gaans, Pauline; Maphosa, Farai; Smidt, Hauke; Grotenhuis, Tim; Rijnaarts, Huub H M

2014-03-01

To improve the coupling of in situ chemical oxidation and in situ bioremediation, a systematic analysis was performed of the effect of chemical oxidation with Fenton's reagent, modified Fenton's reagent, permanganate, or persulfate, on microbial diversity and activity during 8 weeks of incubation in two diesel-contaminated soils (peat and fill). Chemical oxidant and soil type affected the microbial community diversity and biodegradation activity; however, this was only observed following treatment with Fenton's reagent and modified Fenton's reagent, and in the biotic control without oxidation. Differences in the highest overall removal efficiencies of 69 % for peat (biotic control) and 59 % for fill (Fenton's reagent) were partially explained by changes in contaminant soil properties upon oxidation. Molecular analysis of 16S rRNA and alkane monooxygenase (alkB) gene abundances indicated that oxidation with Fenton's reagent and modified Fenton's reagent negatively affected microbial abundance. However, regeneration occurred, and final relative alkB abundances were 1-2 orders of magnitude higher in chemically treated microcosms than in the biotic control. 16S rRNA gene fragment fingerprinting with DGGE and prominent band sequencing illuminated microbial community composition and diversity differences between treatments and identified a variety of phylotypes within Alpha-, Beta-, and Gammaproteobacteria. Understanding microbial community dynamics during coupled chemical oxidation and bioremediation is integral to improved biphasic field application.

UV light assisted decolorization of dark brown colored coffee effluent by photo-Fenton reaction.

PubMed

Tokumura, Masahiro; Ohta, Ayano; Znad, Hussein T; Kawase, Yoshinori

2006-12-01

The photochemical decolorization of coffee effluent has been examined by photo-Fenton (UV/Fe2+/H2O2) process. Effects of UV light intensity, initial coffee concentration, iron dose and H2O2 dose on the color removal of model coffee effluent have been investigated. The rate of decolorization increased with decreasing initial coffee effluent concentration. It was found that the Fe ion dose and UV light intensity enhanced the decolorization rate. The decolorization process of coffee effluent could be divided into three established phases. At the beginning of the photo-Fenton process, the instantaneous and significant increase in color of the solution was found (Phase-I). In the subsequent phase (Phase-II), the decolorization rate was initially fast and subsequently decreased. In Phase-III, the rate was accelerated and then the complete decolorization of model coffee effluent was achieved. In order to elucidate the mechanisms of coffee effluent color removal process, the concentration changes in Fe3+ and Fe2+ besides H2O2 were measured during the course of the photo-Fenton process. The rate-determining step in Phase-II was the photo-Fenton reaction or photoreduction of Fe3+. On the other hand, the decolorization process in Phase-III was highly affected by Fenton reaction or decomposition of H2O2 with Fe2+. About 93% mineralization of 250 mg L(-1) model coffee effluent was achieved after 250 min. A comparative study for TiO2, ZnO and photo-Fenton oxidation processes has been also carried out and the photo-Fenton process was found to be the most effective for color removal of coffee effluent.

Ultrasonic application to boost hydroxyl radical formation during Fenton oxidation and release organic matter from sludge

PubMed Central

Gong, Changxiu; Jiang, Jianguo; Li, De’an; Tian, Sicong

2015-01-01

We examined the effects of ultrasound and Fenton reagent on ultrasonic coupling Fenton oxidation (U+F) pre-treatment processes for the disintegration of wastewater treatment plant sludge. The results demonstrated that U+F treatment could significantly increase soluble chemical oxygen demand (SCOD), total organic carbon (TOC), and extracellular polymeric substances (EPS) concentrations in sludge supernatant. This method was more effective than ultrasonic (U) or Fenton oxidation (F) treatment alone. U+F treatment increased the release of SCOD by 2.1- and 1.4-fold compared with U and F alone, respectively. U+F treatment increased the release of EPS by 1.2-fold compared with U alone. After U+F treatment, sludge showed a considerably finer particle size and looser microstructure based on fluorescence microscopy, and the concentration of hydroxyl radicals (OH•) increased from 0.26 mM by F treatment to 0.43 mM by U+F treatment based on fluorescence spectrophotometer. This demonstrated that U+F treatment improves the release of organic matter from sludge. PMID:26066562

Pyrrolic-N-doped graphene oxide/Fe2O3 mesocrystal nanocomposite: Efficient charge transfer and enhanced photo-Fenton catalytic activity

NASA Astrophysics Data System (ADS)

Liu, Bing; Tian, Lihong; Wang, Ran; Yang, Jinfeng; Guan, Rong; Chen, Xiaobo

2017-11-01

Though α-Fe2O3 has attracted much attention in photocatalytic or Fenton-catalytic degradation of organic contaminants, its performance is still unsatisfactory due to fast recombination of electrons and holes in photocatalytic process and the difficult conversion of Fe(II) and Fe(III) in Fenton reaction. Herein, a pyrrolic N-doped graphene oxide/Fe2O3 mesocrystal (NG-Fe2O3) nanocomposite with good distribution is synthesized by a simple solvothermal method and adjusting the oxygen-containing groups on graphene oxide. The morphology of NG-Fe2O3 contributes to a relatively large BET surface area and an intimate contact between NG and Fe2O3. These two important factors along with the excellent electro-conductivity of pyrrolic-N doped GO result in the efficient separation of electron-hole pairs and fast conversion of Fe(II)and Fe(III) in photo-Fenton synergistic reaction. Thus, a remarkably improved photo-Fenton catalytic activity of NG-Fe2O3 is obtained. The degrading rate on methyl blue increases by 1.5 times and the conversion rate of glyphosate increases by 2.3 times under visible light irradiation, compared to pristine α-Fe2O3 mesocrystals.

4-Phenoxyphenol-Functionalized Reduced Graphene Oxide Nanosheets: A Metal-Free Fenton-Like Catalyst for Pollutant Destruction.

PubMed

Lyu, Lai; Yu, Guangfei; Zhang, Lili; Hu, Chun; Sun, Yong

2018-01-16

Metal-containing Fenton catalysts have been widely investigated. Here, we report for the first time a highly effective stable metal-free Fenton-like catalyst with dual reaction centers consisting of 4-phenoxyphenol-functionalized reduced graphene oxide nanosheets (POP-rGO NSs) prepared through surface complexation and copolymerization. Experimental and theoretical studies verified that dual reaction centers are formed on the C-O-C bridge of POP-rGO NSs. The electron-rich center around O is responsible for the efficient reduction of H 2 O 2 to • OH, while the electron-poor center around C captures electrons from the adsorbed pollutants and diverts them to the electron-rich area via the C-O-C bridge. By these processes, pollutants are degraded and mineralized quickly in a wide pH range, and a higher H 2 O 2 utilization efficiency is achieved. Our findings address the problems of the classical Fenton reaction and are useful for the development of efficient Fenton-like catalysts using organic polymers for different fields.

Coagulation-flocculation sequential with Fenton or Photo-Fenton processes as an alternative for the industrial textile wastewater treatment.

PubMed

GilPavas, Edison; Dobrosz-Gómez, Izabela; Gómez-García, Miguel Ángel

2017-04-15

In this study, the industrial textile wastewater was treated using a chemical-based technique (coagulation-flocculation, C-F) sequential with an advanced oxidation process (AOP: Fenton or Photo-Fenton). During the C-F, Al 2 (SO 4 ) 3 was used as coagulant and its optimal dose was determined using the jar test. The following operational conditions of C-F, maximizing the organic matter removal, were determined: 700 mg/L of Al 2 (SO 4 ) 3  at pH = 9.96. Thus, the C-F allowed to remove 98% of turbidity, 48% of Chemical Oxygen Demand (COD), and let to increase in the BOD 5 /COD ratio from 0.137 to 0.212. Subsequently, the C-F effluent was treated using each of AOPs. Their performances were optimized by the Response Surface Methodology (RSM) coupled with a Box-Behnken experimental design (BBD). The following optimal conditions of both Fenton (Fe 2+ /H 2 O 2 ) and Photo-Fenton (Fe 2+ /H 2 O 2 /UV) processes were found: Fe 2+ concentration = 1 mM, H 2 O 2 dose = 2 mL/L (19.6 mM), and pH = 3. The combination of C-F pre-treatment with the Fenton reagent, at optimized conditions, let to remove 74% of COD during 90 min of the process. The C-F sequential with Photo-Fenton process let to reach 87% of COD removal, in the same time. Moreover, the BOD 5 /COD ratio increased from 0.212 to 0.68 and from 0.212 to 0.74 using Fenton and Photo-Fenton processes, respectively. Thus, the enhancement of biodegradability with the physico-chemical treatment was proved. The depletion of H 2 O 2 was monitored during kinetic study. Strategies for improving the reaction efficiency, based on the H 2 O 2 evolution, were also tested. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fenton-like oxidation of 2,4-DCP in aqueous solution using iron-based nanoparticles as the heterogeneous catalyst.

PubMed

Li, Renchao; Gao, Ying; Jin, Xiaoying; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

2015-01-15

In this report, various iron-based nanoparticles (nZVI, n-Ni/Fe, n-Pd/Fe) were used for both heterogeneous Fenton oxidation of 2,4-dichlorophenol (2,4-DCP) and reductive dechlorination of 2,4-DCP in order to understand their roles in the Fenton oxidation and the reductive degradation of 2,4-DCP. The dechlorination efficiency of 2,4-DCP using nZVI, n-Ni/Fe, n-Fe/Pd and Fe(2)(+) was 6.48%, 6.80%, 15.95%, 5.02%, while Fenton oxidation efficiency of 2,4-DCP was 57.87%, 34.23%, 27.94%, 19.61% after 180 min, respectively. The new findings included a higher dechlorination using n-Fe/Pd due to Pd effective catalysis and the effective heterogeneous Fenton oxidation using nZVI depending on reductive dechlorination and heterogeneous Fenton oxidation occurs simultaneously. However, nZVI as the potential catalyst for heterogeneous Fenton was observed, and SEM, EDS and XRD demonstrate that change on the nZVI surface occurred due to the Fe(2+) leaching, and Total Organic Carbon (TOC) (30.71%) shows that 2,4-DCP was degraded. Furthermore, the experiment indicates that the pH values and concentration of 2,4-DCP significantly impacted on the heterogeneous Fenton oxidation of 2,4-DCP and the data fits well with the pseudo first-order kinetic model, which was a diffusion-controlled reaction. Finally, a possible mechanism for degradation of 2,4-DCP was proposed. Copyright © 2014 Elsevier Inc. All rights reserved.

Advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of heterogeneous Fenton oxidation and biological process.

PubMed

Xu, Peng; Han, Hongjun; Zhuang, Haifeng; Hou, Baolin; Jia, Shengyong; Xu, Chunyan; Wang, Dexin

2015-04-01

Laboratorial scale experiments were conducted in order to investigate a novel system integrating heterogeneous Fenton oxidation (HFO) with anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) process on advanced treatment of biologically pretreated coal gasification wastewater (CGW). The results indicated that HFO with the prepared catalyst (FeOx/SBAC, sewage sludge based activated carbon (SBAC) which loaded Fe oxides) played a key role in eliminating COD and COLOR as well as in improving the biodegradability of raw wastewater. The surface reaction and hydroxyl radicals (OH) oxidation were the mechanisms for FeOx/SBAC catalytic reaction. Compared with ANMBBR-BAF process, the integrated system was more effective in abating COD, BOD5, total phenols (TPs), total nitrogen (TN) and COLOR and could shorten the retention time. Therefore, the integrated system was a promising technology for engineering applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Photo-Fenton and Fenton-like processes for the treatment of the antineoplastic drug 5-fluorouracil under simulated solar radiation.

PubMed

Koltsakidou, Α; Antonopoulou, M; Sykiotou, M; Εvgenidou, Ε; Konstantinou, I; Lambropoulou, D A

2017-02-01

In the present study, photo-Fenton and Fenton-like processes were investigated for the degradation and mineralization of the antineoplastic drug 5-fluorouracil (5-FU). For the optimization of photo-Fenton treatment under simulated solar light (SSL) radiation, the effects of several operating parameters (i.e., 5-FU concentration, Fe 3+ , and oxidant concentration) on the treatment efficiency were studied. According to the results, SSL/[Fe(C 2 Ο 4 ) 3 ] 3- /Η 2 Ο 2 process was the most efficient, since faster degradation of 5-FU and higher mineralization percentages were achieved. All the applied processes followed quite similar transformation routes which include defluorination-hydroxylation as well as pyrimidine ring opening, as demonstrated by the transformation products identified by high resolution mass spectrometry analysis. The toxicity of the treated solutions was evaluated using the Microtox assay. In general, low toxicity was recorded for the initial solution and the solution at the end of the photocatalytic treatment, while an increase in the overall toxicity was observed only at the first stages of SSL/Fe 3+ /Η 2 Ο 2 and SSL/Fe 3+ /S 2 O 8 2- processes.

Removal of refractory contaminants in municipal landfill leachate by hydrogen, oxygen and palladium: a novel approach of hydroxyl radical production.

PubMed

Yu, Yingjian; Chen, Zhulei; Guo, Zhiyuan; Liao, Zhuwei; Yang, Lie; Wang, Jia; Chen, Zhuqi

2015-04-28

Municipal solid waste (MSW) leachate contains various refractory pollutants that pose potential threats to both surface water and groundwater. This paper established a novel catalytic oxidation process for leachate treatment, in which OH is generated in situ by pumping both H2 and O2 in the presence of Pd catalyst and Fe(2+). Volatile fatty acids in the leachate were removed almost completely by aeration and/or mechanical mixing. In this approach, a maximum COD removal of 56.7% can be achieved after 4h when 200mg/L Fe(2+) and 1250mg/L Pd/Al2O3 (pH 3.0) are used as catalysts. After oxidation, the BOD/COD ratio in the proposed process increased from 0.03 to 0.25, indicating that the biodegradability of the leachate was improved. By comparing the efficiency on COD removal and economical aspect of the proposed Pd-based in-situ process with traditional Fenton, electro-Fenton and UV-Fenton for leachate treatments, the proposed Pd-based in-situ process has potential economic advantages over other advanced oxidation processes while the COD removal efficiency was maintained. Copyright © 2015 Elsevier B.V. All rights reserved.

Sunlight, iron and radicals to tackle the resistant leftovers of biotreated winery wastewater.

PubMed

Ioannou, Lida; Velegraki, Theodora; Michael, Costas; Mantzavinos, Dionissios; Fatta-Kassinos, Despo

2013-04-01

Winery wastewater is characterized by high organic content consisting of alcohols, acids and recalcitrant high-molecular-weight compounds (e.g. polyphenols, tannins and lignins). So far, biological treatment constitutes the best available technology for such effluents that are characterized by high seasonal variability; however the strict legislation applied on the reclamation and reuse of wastewaters for irrigation purposes introduces the need for further treatment of the bioresistant fraction of winery effluents. In this context, the use of alternative treatment technologies, aiming to mineralize or transform refractory molecules into others which could be further biodegraded, is a matter of great concern. In this study, a winery effluent that had already been treated in a sequencing batch reactor was subjected to further purification by homogeneous and heterogeneous solar Fenton oxidation processes. The effect of various operating variables such as catalyst and oxidant concentration, initial pH, temperature and lamp power on the abatement of chemical oxygen demand (COD), dissolved organic carbon (DOC), color, total phenolics and ecotoxicity has been assessed in the homogeneous solar Fenton process. In addition, a comparative assessment between homogeneous and heterogeneous solar Fenton processes was performed. In the present study the homogeneous solar Fenton process has been demonstrated to be the most effective process, yielding COD, DOC and total phenolics removal of about 69%, 48% and 71% in 120 min of the photocatalytic treatment, respectively.

Remediation of TCE-contaminated groundwater using acid/BOF slag enhanced chemical oxidation.

PubMed

Tsai, T T; Kao, C M; Wang, J Y

2011-04-01

The objective of this study was to evaluate the potential of applying acid/H(2)O(2)/basic oxygen furnace slag (BOF slag) and acid/S(2)O(8)(2-)/BOF slag systems to enhance the chemical oxidation of trichloroethylene (TCE)-contaminated groundwater. Results from the bench-scale study indicate that TCE oxidation via the Fenton-like oxidation process can be enhanced with the addition of BOF slag at low pH (pH=2-5.2) and neutral (pH=7.1) conditions. Because the BOF slag has iron abundant properties (14% of FeO and 6% of Fe(2)O(3)), it can be sustainably reused for the supplement of iron minerals during the Fenton-like or persulfate oxidation processes. Results indicate that higher TCE removal efficiency (84%) was obtained with the addition of inorganic acid for the activation of Fenton-like reaction compared with the experiments with organic acids addition (with efficiency of 10-15% lower) (BOF slag=10gL(-1); initial pH=5.2). This could be due to the fact that organic acids would compete with TCE for available oxidants. Results also indicate that the pH value had a linear correlation with the observed first-order decay constant of TCE, and thus, lower pH caused a higher TCE oxidation rate. Copyright © 2011 Elsevier Ltd. All rights reserved.

Oxidation of Levafix CA reactive azo-dyes in industrial wastewater of textile dyeing by electro-generated Fenton's reagent.

PubMed

El-Desoky, Hanaa S; Ghoneim, Mohamed M; El-Sheikh, Ragaa; Zidan, Naglaa M

2010-03-15

The indirect electrochemical removal of pollutants from effluents has become an attractive method in recent years. Removal (decolorization and mineralization) of Levafix Blue CA and Levafix Red CA reactive azo-dyes from aqueous media by electro-generated Fenton's reagent (Fe(2+)/H(2)O(2)) using a reticulated vitreous carbon cathode and a platinum gauze anode was optimized. Progress of oxidation (decolorization and mineralization) of the investigated azo-dyes with time of electro-Fenton's reaction was monitored by UV-visible absorbance measurements, Chemical oxygen demand (COD) removal and HPLC analysis. The results indicated that the electro-Fenton's oxidation system is efficient for treatment of such types of reactive dyes. Oxidation of each of the investigated azo-dyes by electro-generated Fenton's reagent up to complete decolorization and approximately 90-95% mineralization was achieved. Moreover, the optimized electro-Fenton's oxidation was successfully applied for complete decolorization and approximately 85-90% mineralization of both azo-dyes in real industrial wastewater samples collected from textile dyeing house at El-Mahalla El-Kobra, Egypt. (c) 2009 Elsevier B.V. All rights reserved.

Regulation of Electrochemically Generated H2O2 in Situ from a Novel CB-PTFE Cathode for Transformation of Chlorine Benzene in Groundwater

NASA Astrophysics Data System (ADS)

Jiang, J.; Zhang, X.; Li, G.

2014-12-01

Fenton's reagents (H2O2 and Fe2+ catalyst commonly) have been widely used in soil and groundwater remediation. But the excessive H2O2 decomposition and the pH modification (acidification) problem have been limitations for Fenton based remediation strategies. The Electro-Fenton (E- Fenton) processes has been recently developed to solve the problems, in which Fe2+ or H2O2are generated in situ as continuing source of Fenton's reagents. In this study, a novel CB-PTFE cathode and a Fe cathode were employed to generate H2O2 and Fe2+ in situ simultaneously. The generated reactive oxidizing species, i.e., O2,H2O2 and hydroxyl radical (HO•), oxidized bio-refractory organics to nontoxic matters in groundwater. Automatic pH adjustments are achieved by appropriately arraying the electrodes. Laboratory batch tests and column tests for the E-Fenton oxidation and hybrid electrolysis system were conducted to evaluate the transformation efficiency of chlorine benzene. Results from batch experiments suggested the CB-PTFE cathode was effective for reducing O2 to H2O2. The H2O2 concentration reached 468 mg/L under the condition of pH 3.0 and 30mA/cm2 in 60 minutes, which was 5 and 10 times of that with a graphite and C-felt cathode. The removal efficiency of chlorine benzene reached 80% in 20 minutes. Both chlorine benzene degradation and H2O2 production increased with decreasing solution pH and increasing current density. The results from the columns tests proved that the in situ E-Fenton system is a feasible method for groundwater remediation.

Ferrocene-catalyzed heterogeneous Fenton-like degradation mechanisms and pathways of antibiotics under simulated sunlight: A case study of sulfamethoxazole.

PubMed

Li, Yingjie; Zhang, Biaojun; Liu, Xiangliang; Zhao, Qun; Zhang, Heming; Zhang, Yuechao; Ning, Ping; Tian, Senlin

2018-07-05

Readily-available and efficient catalyst is essential for activating oxidants to produce reactive species for deeply remediating water bodies contaminated by antibiotics. In this study, Ferrocene (Fc) was introduced to establish a heterogeneous photo-Fenton system for the degradation of sulfonamide antibiotics, taking sulfamethoxazole as a representative. Results showed that the removal of sulfamethoxazole was effective in Fc-catalyzed photo-Fenton system. Electron spin resonance and radical scavenging experiments verified that there was a photoindued electron transfer process from Fc to H 2 O 2 and dissolved oxygen resulting in the formation of OH that was primarily responsible for the degradation of sulfamethoxazole. The reactions of OH with substructure model compounds of sulfamethoxazole unveiled that aniline moiety was the preferable reaction site of sulfamethoxazole, which was verified by the formation of hydroxylated product and the dimer of sulfamethoxazole in Fc-catalyzed photo-Fenton system. This heterogeneous photo-Fenton system displayed an effective degradation efficiency even in a complex water matrices, and Fc represented a long-term stability by using the catalyst for multiple cycles. These results demonstrate that Fc-catalyzed photo-Fenton oxidation may be an efficient approach for remediation of wastewater containing antibiotics. Copyright © 2018. Published by Elsevier B.V.

Hydroxyl radical production by a heterogeneous Fenton reaction supported in insoluble tannin from bark of Pinus radiata.

PubMed

Romero, Romina; Contreras, David; Segura, Cristina; Schwederski, Brigitte; Kaim, Wolfgang

2017-03-01

Fenton reactions driven by dihydroxybenzenes (DHBs) have been used for pollutant removal via advanced oxidation processes (AOPs), but such systems have the disadvantage of DHB release into the aqueous phase. In this work, insoluble tannins from bark can be used to drive Fenton reactions and as a heterogeneous support. This avoids the release of DHBs into the aqueous phase and can be used for AOPs. The production of ·OH was investigated using a spin-trapping electron paramagnetic resonance technique (5-dimethyl-1-pyrroline-N-oxide/·OH) in the first minute of the reaction and a high-performance liquid chromatography-fluorescence technique (coumarin/7-hydroxycoumarin) for 20 min. The ·OH yield achieved using insoluble tannins from Pinus radiata bark was higher than that achieved using catechin to drive the Fenton reaction. The Fenton-like system driven by insoluble tannins achieved 92.6 ± 0.3 % degradation of atrazine in 30 min. The degradation kinetics of atrazine was linearly correlated with ·OH production. The increased reactivity in ·OH production and insolubility of the ligand are promising for the development of a new technique for degradation of pollutants in wastewater using heterogeneous Fenton systems.

The fate of MtBE during Fenton-like treatments through laboratory scale column tests.

PubMed

Piscitelli, Daniela; Zingaretti, Daniela; Verginelli, Iason; Gavasci, Renato; Baciocchi, Renato

2015-12-01

In Situ Chemical Oxidation (ISCO) based on the Fenton's process is a proven technology for the treatment of groundwater contaminated by organic compounds. Nevertheless, the application of this treatment process to methyl tert-butyl ether (MtBE) is questioned, as there are concerns about its capacity to achieve complete mineralization. Many existing studies have focused on water contaminated by MtBE and are thus not representative of in situ treatments since they do not consider the presence of soil. In this work, the effectiveness of a Fenton-like process for MtBE treatment was proven in soil column tests performed at operating conditions (i.e., oxidant and contaminant concentration and flow rates) resembling those typically used for in situ applications. No MtBE by-products were detected in any of the tested conditions, thus suggesting that the tert-butyl group of MtBE was completely degraded. A mass balance based on the CO2 produced was used as evidence that most of the MtBE removed was actually mineralized. Finally, the obtained results show that preconditioning of soil with a chelating agent (EDTA) significantly enhanced MtBE oxidation. Copyright © 2015 Elsevier B.V. All rights reserved.

A two-stage pretreatment process using dilute hydrochloric acid followed by Fenton oxidation to improve sugar recovery from corn stover.

PubMed

Li, Wenzhi; Liu, Qiyu; Ma, Qiaozhi; Zhang, Tingwei; Ma, Longlong; Jameel, Hasan; Chang, Hou-Min

2016-11-01

A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120°C for 40min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1g/L FeSO4·7H2O and 30g/L H2O2) is performed at room temperature (about 20°C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

Efficient mineralization of the antibiotic trimethoprim by solar assisted photoelectro-Fenton process driven by a photovoltaic cell.

PubMed

Zhang, Yanyu; Wang, Aimin; Tian, Xiujun; Wen, Zhenjun; Lv, Hanjiao; Li, Desheng; Li, Jiuyi

2016-11-15

In this study, a novel self-sustainable solar assisted photoelectro-Fenton (SPEF) system driven by a solar photovoltaic cell was developed for the efficient mineralization of antibiotic trimethoprim (TMP) in water. A comparative degradation of 200mgL(-1) TMP by RuO2/Ti anodic oxidation (AO), anodic oxidation with H2O2 electrogeneration (AO-H2O2), electro-Fenton (EF) and SPEF was investigated. SPEF was proved to exhibit the highest oxidation power, i.e., more than 80% TOC was removed after 360min SPEF treatment of 200mgL(-1) of TMP under optimal conditions at pH 3.0, 1.0mM Fe(2+) and 18mAcm(-2). Influences of current density, pH, initial Fe(2+) and initial TMP concentration on SPEF process were also studied. Ten aromatic intermediates generated from hydroxylation, carbonylation and demethylation reactions were identified using UPLC-QTOF-MS/MS system during the SPEF treatment, together with three carboxylic acids (oxamic, oxalic and formic acids) and two inorganic ions (NH4(+) and NO3(-)) measured. Therefore, a reasonable pathway of TMP degradation in SPEF process was proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

Catalytic degradation of picric acid by heterogeneous Fenton-based processes.

PubMed

Dulova, Niina; Trapido, Marina; Dulov, Aleksandr

2011-01-01

The efficiency of goethite, magnetite and iron powder (Fe0) in catalysing the Fenton-based oxidation of picric acid (PA) in aqueous solution was studied. The effect of pH, hydrogen peroxide concentration, and catalyst type and dosage on treatment efficacy was investigated. The adsorption of PA from aqueous solution by heterogeneous catalysts was also examined. The results demonstrated negligible PA removal in H2O2/alpha-FeOOH and H2O2/Fe3O4 systems independent of process pH, and hydrogen peroxide and catalyst dosage. The PA adsorption effects of both iron oxides turned out to be insignificant for all studied pH values and catalyst dosages. The H2O2/Fe0 system proved efficient at degrading PA, but only under acidic conditions (pH 3). The results indicated that, due to rather fast leaching of ferrous ions from the iron powder surface, PA degradation was carried out mainly by the classic Fenton oxidation mechanism in the bulk solution. The adsorption of PA onto the iron powder surface may also contribute to the overall efficiency of PA degradation.

Remediation of water contaminated with diesel oil using a coupled process: Biological degradation followed by heterogeneous Fenton-like oxidation.

PubMed

Chen, Yuan; Lin, Jiajiang; Chen, Zuliang

2017-09-01

The treatment of a synthetically prepared wastewater containing diesel oil has been investigated using combined treatment schemes based on the biological treatment followed by an advanced oxidation process. 78% of diesel oil was degraded by Acinetobacter venetianus in 96 h, while the removal efficiency of chemical oxygen demand (COD) in the aqueous phase was only 56.8%, indicating that degraded metabolites existed in solution. To solve this problem, a Fenton-like system consisting of nanoscale zero-valent iron (nZVI) and hydrogen peroxide was used for further oxidation of the metabolites after biodegradation. Results showed that the total COD removal increased from 56.8% to 89% under the optimal condition. In addition, effects of initial pH (2.0-9.0), ZVI dosage (0-2.0 g L-1), hydrogen peroxide (H 2 O 2 ) dosage concentration (0-15 mmol L-1) and temperature (298-308 K) on the treatment efficiency of the combined process were studied. Scanning electron microscopy (SEM) demonstrated that changes to the surface of nZVI occurred. GC-MS revealed that the degraded metabolites were mineralized practically by nZVI/H 2 O 2 system. The results points towards the potential of Fenton-like oxidation as a short post-treatment after a biological process for the treatment of organic pollutants in wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Photo-Fenton-assisted ozonation of p-Coumaric acid in aqueous solution.

PubMed

Monteagudo, J M; Carmona, M; Durán, A

2005-08-01

The degradation of p-Coumaric acid present in olive oil mill wastewater was investigated as a pretreatment stage to obtain more easily biodegradable molecules, with lower toxicity that facilitates subsequent anaerobic digestion. Thus, photo-Fenton-assisted ozonation has been studied and compared with ozonation at alkaline pH and conventional single ultraviolet (UV) and acid ozonation treatments. In the combined process, the overall kinetic rate constant was split into various components: direct oxidation by UV light, direct oxidation by ozone and oxidation by hydroxyl radicals. Molecular and/or radical ozone reaction was studied by conducting the reaction in the presence and absence of tert-butylalcohol at pHs 2, 7 and 9. Ozone oxidation rate increases with pH or by the addition of Fenton reagent and/or UV radiation due to generation of hydroxyl radicals, *OH. Hydrogen peroxide and ferrous ion play a double role during oxidation since at low concentrations they act as initiators of hydroxyl radicals but at high concentrations they act as radical scavengers. Finally, the additional levels of degradation by formation of hydroxyl radicals have been quantified in comparison to the conventional single processes and an equation is proposed for the reaction rate as a function of studied operating variables.

Photocatalytic degradation and photo-Fenton oxidation of Congo red dye pollutants in water using natural chromite—response surface optimization

NASA Astrophysics Data System (ADS)

Shaban, Mohamed; Abukhadra, Mostafa R.; Ibrahim, Suzan S.; Shahien, Mohamed. G.

2017-12-01

Refined natural Fe-chromite was characterized by XRD, FT-IR, reflected polarized microscope, XRF and UV spectrophotometer. Photocatalytic degradation and photo-Fenton oxidation of Congo red dye by Fe-chromite was investigated using 1 mL H2O2. The degradation of dye was studied as a function of illumination time, chromite mass, initial dye concentration, and pH. Fe-chromite acts as binary oxide system from chromium oxide and ferrous oxide. Thus, it exhibits photocatalytic properties under UV illumination and photo-Fenton oxidation after addition of H2O2. The degradation in the presence of H2O2 reached the equilibrium stage after 8 h (59.4%) but in the absence of H2O2 continued to 12 h (54.6%). Photocatalytic degradation results fitted well with zero, first order and second order kinetic model but it represented by second order rather than by the other models. While the photo-Fenton oxidation show medium fitting with the second order kinetic model only. The values of kinetic rate constants for the photo-Fenton oxidation were greater than those for the photocatalytic degradation. Thus, degradation of Congo red dye using chromite as catalyst is more efficient by photo-Fenton oxidation. Based on the response surface analysis, the predicted optimal conditions for maximum removal of Congo red dye by photocatalytic degradation (100%) were 12 mg/l, 0.14 g, 3, and 11 h for dye concentration, chromite mass, pH, and illumination time, respectively. Moreover, the optimum condition for photo-Fenton oxidation of dye (100%) is 13.5 mg/l, 0.10 g, 4, and 10 h, respectively.

Research on the Treatment of Aluminum Alloy Chemical Milling Wastewater with Fenton Process

NASA Astrophysics Data System (ADS)

Zong-liang, Huang; Ru, Li; Peng, Luo; Jun-li, Gu

2018-03-01

The aluminum alloy chemical milling wastewater was treated by Fenton method. The effect of pH value, reaction time, rotational speed, H2O2 dosage, Fe2+ dosage and the molar ratio between H2O2 and Fe2+ on the COD removal rate of aluminum alloy chemical milling wastewater were investigated by single factor experiment and orthogonal experiment. The results showed that the optimum operating conditions for Fenton oxidation were as follows: the initial pH value was 3, the rotational speed was 250r/min, the molar ratio of H2O2 and Fe2+ was 8, the reaction time was 90 min. Under the optimum conditions, the removal rate of the wastewater’s COD is about 72.36%. In the reaction kinetics that aluminum alloy chemical milling wastewater was oxidized and degraded by Fenton method under the optimum conditions, the reaction sequence of the initial COD was 0.8204.

Electrochemical advanced oxidation processes as decentralized water treatment technologies to remediate domestic washing machine effluents.

PubMed

Dos Santos, Alexsandro Jhones; Costa, Emily Cintia Tossi de Araújo; da Silva, Djalma Ribeiro; Garcia-Segura, Sergi; Martínez-Huitle, Carlos Alberto

2018-03-01

Water scarcity is one of the major concerns worldwide. In order to secure this appreciated natural resource, management and development of water treatment technologies are mandatory. One feasible alternative is the consideration of water recycling/reuse at the household scale. Here, the treatment of actual washing machine effluent by electrochemical advanced oxidation processes was considered. Electrochemical oxidation and electro-Fenton technologies can be applied as decentralized small-scale water treatment devices. Therefore, efficient decolorization and total organic abatement have been followed. The results demonstrate the promising performance of solar photoelectro-Fenton process, where complete color and organic removal was attained after 240 min of treatment under optimum conditions by applying a current density of 66.6 mA cm -2 . Thus, electrochemical technologies emerge as promising water-sustainable approaches.

Environmental application of millimetre-scale sponge iron (s-Fe0) particles (IV): New insights into visible light photo-Fenton-like process with optimum dosage of H2O2 and RhB photosensitizers.

PubMed

Ju, Yongming; Yu, Yunjiang; Wang, Xiaoyan; Xiang, Mingdeng; Li, Liangzhong; Deng, Dongyang; Dionysiou, Dionysios D

2017-02-05

In this study, we firstly develop the photo-Fenton-like system with millimetric sponge iron (s-Fe 0 ), H 2 O 2 , visible light (vis, λ≥420nm) and rhodamine B (RhB), and present a comprehensive study concerning the mechanism. Thus, we investigate (1) the adsorption of RhB onto s-Fe 0 , (2) the photo-Fenton-like removal of RhB over iron oxides generated from the corrosion of s-Fe 0 , (3) the homogeneous photo-Fenton removal of RhB over Fe 2+ or Fe 3+ , (4) the Fe 3+ -RhB complexes, and (5) the photo-Fenton-like removal of tetrabromobisphenol A (TBBPA). The results show that neither the adsorption process over s-Fe 0 nor the photo-Fenton-like process over FeOOH, Fe 3 O 4 and Fe 2 O 3 , achieved efficient removal of RhB. For comparison, in homogeneous photo-Fenton process, the presence of Fe 3+ ions, rather than Fe 2+ ions, effectively eliminated RhB. Furthermore, the UV-vis spectra showing new absorbance at∼285nm indicate the complexes of RhB and Fe 3+ ions, adopting vis photons to form excited state and further eject one electron via ligand-to-metal charge-transfer to activate H 2 O 2 . Additionally, efficient TBBPA removal was obtained only in the presence of RhB. Accordingly, the s-Fe 0 - based photo-Fenton-like process assisted with dyestuff wastewater is promising for removing a series of persistent organic pollutants. Copyright © 2016 Elsevier B.V. All rights reserved.

Induced effects of advanced oxidation processes

PubMed Central

Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

2014-01-01

Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields. PMID:24503715

Induced effects of advanced oxidation processes.

PubMed

Liu, Peng; Li, Chaolin; Zhao, Zhuanjun; Lu, Gang; Cui, Haibo; Zhang, Wenfang

2014-02-07

Hazardous organic wastes from industrial, military, and commercial activities represent one of the greatest challenges to human beings. Advanced oxidation processes (AOPs) are alternatives to the degradation of those organic wastes. However, the knowledge about the exact mechanisms of AOPs is still incomplete. Here we report a phenomenon in the AOPs: induced effects, which is a common property of combustion reaction. Through analysis EDTA oxidation processes by Fenton and UV-Fenton system, the results indicate that, just like combustion, AOPs are typical induction reactions. One most compelling example is that pre-feeding easily oxidizable organic matter can promote the oxidation of refractory organic compound when it was treated by AOPs. Connecting AOPs to combustion, it is possible to achieve some helpful enlightenment from combustion to analyze, predict and understand AOPs. In addition, we assume that maybe other oxidation reactions also have induced effects, such as corrosion, aging and passivation. Muchmore research is necessary to reveal the possibilities of induced effects in those fields.

Degradation of Tetracycline with BiFeO3 Prepared by a Simple Hydrothermal Method

PubMed Central

Xue, Zhehua; Wang, Ting; Chen, Bingdi; Malkoske, Tyler; Yu, Shuili; Tang, Yulin

2015-01-01

BiFeO3 particles (BFO) were prepared by a simple hydrothermal method and characterized. BFO was pure, with a wide particle size distribution, and was visible light responsive. Tetracycline was chosen as the model pollutant in this study. The pH value was an important factor influencing the degradation efficiency. The total organic carbon (TOC) measurement was emphasized as a potential standard to evaluate the visible light photocatalytic degradation efficiency. The photo-Fenton process showed much better degradation efficiency and a wider pH adaptive range than photocatalysis or the Fenton process solely. The optimal residual TOC concentrations of the photocatalysis, Fenton and photo-Fenton processes were 81%, 65% and 21%, while the rate constants of the three processes under the same condition where the best residual TOC was acquired were 9.7 × 10−3, 3.2 × 10−2 and 1.5 × 10−1 min−1, respectively. BFO was demonstrated to have excellent stability and reusability. A comparison among different reported advanced oxidation processes removing tetracycline (TC) was also made. Our findings showed that the photo-Fenton process had good potential for antibiotic-containing waste water treatment. It provides a new method to deal with antibiotic pollution. PMID:28793568

Roles of iron species and pH optimization on sewage sludge conditioning with Fenton's reagent and lime.

PubMed

Yu, Wenbo; Yang, Jiakuan; Shi, Yafei; Song, Jian; Shi, Yao; Xiao, Jun; Li, Chao; Xu, Xinyu; He, Shu; Liang, Sha; Wu, Xu; Hu, Jingping

2016-05-15

Conditioning sewage sludge with Fenton's reagent could effectively improve its dewaterability. However, drawbacks of conditioning with Fenton's reagent are requirement of acidic conditions to prevent iron precipitation and subsequent neutralization with alkaline additive to obtain the pH of the filtrate close to neutrality. In this study, roles of pH were thoroughly investigated in the acidification pretreatment, Fenton reaction, and the final filtrate after conditioning. Through the response surface methodology (RSM), the optimal dosages of H2SO4, Fe(2+), H2O2, and lime acted as a neutralizer were found to be 0 (no acidification), 47.9, 34.3 and 43.2 mg/g DS (dry solids). With those optimal doses, water content of the dewatered sludge cakes could be reduced to 55.8 ± 0.6 wt%, and pH of the final filtrate was 6.6 ± 0.2. Fenton conditioning without initial acidification can simplify the conditioning process and reduce the usage of lime. The Fe(3+) content in the sludge cakes showed a close correlation with the dewaterability of conditioned sludge, i.e., the water content of sludge cakes, SRF (specific resistance to filtration), CST (capillary suction time), bound water content, and specific surface area. It indicated that the coagulation by Fe(3+) species in Fenton reaction could play an important role, compared to traditional Fenton oxidation effect on sludge conditioning. Thus, a two-step mechanism of Fenton oxidation and Fe(III) coagulation was proposed in sewage sludge conditioning. The mechanisms include the following: (1) extracellular polymeric substances (EPS) were firstly degraded into dissolved organics by Fenton oxidation; (2) bound water was converted to free water due to degradation of EPS; (3) the sludge particles were disintegrated into small ones by oxidation; (4) Fe(3+) generated from Fenton reaction acted as a coagulant to agglomerate smaller sludge particles into larger dense particles with less bond water; (5) finally, the dewatered sludge cakes were obtained, with less small pores (1-10 nm) that contributed to water affinity, but with more large pores (>10 nm) that contributed to a permeable, rigid lattice structure. Morphology of the Fenton-conditioned sludge cake exhibited a porous structure. The estimated cost of the composite conditioner, Fenton's reagent and lime, is USD$ 43.8/t DS, which is less than that of ferric chloride and lime (USD$ 54/t DS). Furthermore, pH of the final filtrate using this composite conditioner is about 6.6. Comparatively, that using ferric chloride and lime is as high as 12.4. Copyright © 2016 Elsevier Ltd. All rights reserved.

Micropollutant degradation, bacterial inactivation and regrowth risk in wastewater effluents: Influence of the secondary (pre)treatment on the efficiency of Advanced Oxidation Processes.

PubMed

Giannakis, Stefanos; Voumard, Margaux; Grandjean, Dominique; Magnet, Anoys; De Alencastro, Luiz Felippe; Pulgarin, César

2016-10-01

In this work, disinfection by 5 Advanced Oxidation Processes was preceded by 3 different secondary treatment systems present in the wastewater treatment plant of Vidy, Lausanne (Switzerland). 5 AOPs after two biological treatment methods (conventional activated sludge and moving bed bioreactor) and a physiochemical process (coagulation-flocculation) were tested in laboratory scale. The dependence among AOPs efficiency and secondary (pre)treatment was estimated by following the bacterial concentration i) before secondary treatment, ii) after the different secondary treatment methods and iii) after the various AOPs. Disinfection and post-treatment bacterial regrowth were the evaluation indicators. The order of efficiency was Moving Bed Bioreactor > Activated Sludge > Coagulation-Flocculation > Primary Treatment. As far as the different AOPs are concerned, the disinfection kinetics were: UVC/H2O2 > UVC and solar photo-Fenton > Fenton or solar light. The contextualization and parallel study of microorganisms with the micropollutants of the effluents revealed that higher exposure times were necessary for complete degradation compared to microorganisms for the UV-based processes and inversed for the Fenton-related ones. Nevertheless, in the Fenton-related systems, the nominal 80% removal of micropollutants deriving from the Swiss legislation, often took place before the elimination of bacterial regrowth risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of Acid Orange 7 Degradation in Heterogeneous Fenton-like Reaction Using Fe3-xCoxO4 Catalyst

NASA Astrophysics Data System (ADS)

Ibrahim, M. Z.; Alrozi, R.; Zubir, N. A.; Bashah, N. A.; Ali, S. A. Md; Ibrahim, N.

2018-05-01

The oxidation process such as heterogeneous Fenton and/or Fenton-like reactions is considered as an effective and efficient method for treatment of dye degradation. In this study, the degradation of Acid Orange 7 (AO7) was investigated by using Fe3-xCoxO4 as a heterogeneous Fenton-like catalyst. Response surface methodology (RSM) was used to optimize the operational parameters condition and the interaction of two or more parameters. The parameter studies were catalyst dosage (X1 ), pH (X2 ) and H2O2 concentration (X3 ) towards AO7 degradation. Based on analysis of variance (ANOVA), the derived quadratic polynomial model was significant whereby the predicted values matched the experimental values with regression coefficient of R2 = 0.9399. The optimum condition for AO7 degradation was obtained at catalyst dosage of 0.84 g/L, pH of 3 and H2O2 concentration of 46.70 mM which resulted in 86.30% removal of AO7 dye. These findings present new insights into the influence of operational parameters in the heterogeneous Fenton-like oxidation of AO7 using Fe3-xCoxO4 catalyst.

Enhancement of Fenton oxidation for removing organic matter from hypersaline solution by accelerating ferric system with hydroxylamine hydrochloride and benzoquinone.

PubMed

Peng, Siwei; Zhang, Weijun; He, Jie; Yang, Xiaofang; Wang, Dongsheng; Zeng, Guisheng

2016-03-01

Fenton oxidation is generally inhibited in the presence of a high concentration of chloride ions. This study investigated the feasibility of using benzoquinone (BQ) and hydroxylamine hydrochloride (HA) as Fenton enhancers for the removal of glycerin from saline water under ambient temperature by accelerating the ferric system. It was found that organics removal was not obviously affected by chloride ions of low concentration (less than 0.1mol/L), while the mineralization rate was strongly inhibited in the presence of a large amount of chloride ions. In addition, ferric hydrolysis-precipitation was significantly alleviated in the presence of HA and BQ, and HA was more effective in reducing ferric ions into ferrous ions than HA, while the H2O2 decomposition rate was higher in the BQ-Fenton system. Electron spin resonance analysis revealed that OH production was reduced in high salinity conditions, while it was enhanced after the addition of HA and BQ (especially HA). This study provided a possible solution to control and alleviate the inhibitory effect of chloride ions on the Fenton process for organics removal. Copyright © 2015. Published by Elsevier B.V.

Occurrence and Removal of Organic Micropollutants in Landfill Leachates Treated by Electrochemical Advanced Oxidation Processes.

PubMed

Oturan, Nihal; van Hullebusch, Eric D; Zhang, Hui; Mazeas, Laurent; Budzinski, Hélène; Le Menach, Karyn; Oturan, Mehmet A

2015-10-20

In recent years, electrochemical advanced oxidation processes have been shown to be an effective alternative for the removal of refractory organic compounds from water. This study is focused on the effective removal of recalcitrant organic matter (micropollutants, humic substances, etc.) present in municipal solid waste landfill leachates. A mixture of eight landfill leachates has been studied by the electro-Fenton process using a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode or by the anodic oxidation process with a BDD anode. These processes exhibit great oxidation ability due to the in situ production of hydroxyl radicals ((•)OH), a highly powerful oxidizing species. Both electrochemical processes were shown to be efficient in the removal of dissolved total organic carbon (TOC) from landfill leachates. Regarding the electro-Fenton process, the replacement of the classical anode Pt by the anode BDD allows better performance in terms of dissolved TOC removal. The occurrence and removal yield of 19 polycyclic aromatic hydrocarbons, 15 volatile organic compounds, 7 alkylphenols, 7 polychlorobiphenyls, 5 organochlorine pesticides, and 2 polybrominated diphenyl ethers in landfill leachate were also investigated. Both electrochemical processes allow one to reach a quasicomplete removal (about 98%) of these organic micropollutants.

Physicochemical treatments of anionic surfactants wastewater: Effect on aerobic biodegradability.

PubMed

Aloui, Fathi; Kchaou, Sonia; Sayadi, Sami

2009-05-15

The effect of different physicochemical treatments on the aerobic biodegradability of an industrial wastewater resulting from a cosmetic industry has been investigated. This industrial wastewater contains 11423 and 3148mgL(-1) of chemical oxygen demand (COD) and anionic surfactants, respectively. The concentration of COD and anionic surfactants were followed throughout the diverse physicochemical treatments and biodegradation experiments. Different pretreatments of this industrial wastewater using chemical flocculation process with lime and aluminium sulphate (alum), and also advanced oxidation process (electro-coagulation (Fe and Al) and electro-Fenton) led to important COD and anionic surfactants removals. The best results were obtained using electro-Fenton process, exceeding 98 and 80% of anionic surfactants and COD removals, respectively. The biological treatment by an isolated strain Citrobacter braakii of the surfactant wastewater, as well as the pretreated wastewater by the various physicochemical processes used in this study showed that the best results were obtained with electro-Fenton pretreated wastewater. The characterization of the treated surfactant wastewater by the integrated process (electro-coagulation or electro-Fenton)-biological showed that it respects Tunisian discharge standards.

Efficient degradation of Acid Orange 7 in aqueous solution by iron ore tailing Fenton-like process.

PubMed

Zheng, Jianming; Gao, Zhanqi; He, Huan; Yang, Shaogui; Sun, Cheng

2016-05-01

An effective method based on iron ore tailing Fenton-like process was studied for removing an azo dye, Acid Orange 7 (AO7) in aqueous solution. Five tailings were characterized by X-ray fluorescence spectroscope (XFS), Brunner-Emmet-Teller (BET) measurement, and Scanning Electron Microscope (SEM). The result of XFS showed that Fe, Si and Ca were the most abundant elements and some toxic heavy metals were also present in the studied tailings. The result of BET analysis indicated that the studied tailings had very low surface areas (0.64-5.68 m(2) g(-1)). The degradation efficiencies of AO7 were positively correlated with the content of iron oxide and cupric oxide, and not related with the BET surface area of the tailings. The co-existing metal elements, particularly Cu, might accelerate the heterogeneous Fenton-like reaction. The effects of other parameters on heterogeneous Fenton-like degradation of AO7 by a converter slag iron tailing (tailing E) which contains highest iron oxide were also investigated. The tailing could be reused 10 times without significant decrease of the catalytic capacity. Very low amount of iron species and almost undetectable toxic elements were leached in the catalytic degradation of AO7 by the tailing E. The reaction products were identified by gas chromatography-mass spectrometry and a possible pathway of AO7 degradation was proposed. This study not only provides an effective method for removing azo dyes in polluted water by employing waste tailings as Fenton-like catalysts, but also uses waste tailings as the secondary resource. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of Fenton reaction for the treatment of leachate from composting of different wastes.

PubMed

Trujillo, Daniel; Font, Xavier; Sánchez, Antoni

2006-11-02

The oxidation of leachate coming from the composting of two organic wastes (wastewater sludge and organic fraction of municipal solid wastes) using the Fenton's reagent was studied using different ratios [Fe(2+)]/[COD](0) and maintaining a ratio [H(2)O(2)]/[COD](0) equal to 1. The optimal conditions for Fenton reaction were found at a ratio [Fe(2+)]/[COD](0) equal to 0.1. Both leachates were significantly oxidized under these conditions in terms of COD removal (77 and 75% for leachate from wastewater sludge composting and leachate from organic fraction of municipal solid wastes, respectively) and BOD(5) removal (90 and 98% for leachate from wastewater sludge composting and leachate from organic fraction of municipal solid wastes, respectively). Fenton's reagent was found to oxidize preferably biodegradable organic matter of leachate. In consequence, a decrease in the biodegradability of leachates was observed after Fenton treatment for both leachates. Nevertheless, Fenton reaction proved to be a feasible technique for the oxidation of the leachate under study, and it can be considered a suitable treatment for this type of wastewaters.

Impact of chemical oxidation on indigenous bacteria and mobilization of nutrients and subsequent bioremediation of crude oil-contaminated soil.

PubMed

Xu, Jinlan; Deng, Xin; Cui, Yiwei; Kong, Fanxing

2016-12-15

Fenton pre-oxidation provides nutrients to promote bioremediation. However, the effects of the indigenous bacteria that remain following Fenton oxidation on nutrient mobilization and subsequent bioremediation remain unclear. Experiments were performed with inoculation with native bacteria and foreign bacteria or without inoculation after four regimens of stepwise pre-oxidations. The effects of the indigenous bacteria remaining after stepwise oxidation on nutrient mobilization and subsequent bioremediation over 80 days were investigated. After stepwise Fenton pre-oxidation at a low H 2 O 2 concentration (225×4), the remaining indigenous bacterial populations reached their peak (4.8±0.17×10 6 CFU/g), the nutrients were mobilized rapidly, and the subsequent bioremediation of crude oil was improved (biodegradation efficiency of 35%). However, after stepwise Fenton pre-oxidation at a high H 2 O 2 concentration (450×4), only 3.6±0.16×10 3 CFU/g of indigenous bacteria remained, and the indigenous bacteria that degrade C 15 -C 30 alkanes were inhibited. The nutrient mobilization was then highly limited, and only 19% of total petroleum hydrocarbon was degraded. Furthermore, the recovery period after the low H 2 O 2 concentration stepwise Fenton pre-oxidation (225×4) was less than 20 days, which was 20-30 days shorter than with the other pre-oxidation treatments. Therefore, stepwise Fenton pre-oxidation at a low H 2 O 2 concentration protects indigenous bacterial populations and improves the nutrient mobilization and subsequent bioremediation. Copyright © 2016 Elsevier B.V. All rights reserved.

Conventional and advanced oxidation processes used in disinfection of treated urban wastewater.

PubMed

Rodríguez-Chueca, J; Ormad, M P; Mosteo, R; Sarasa, J; Ovelleiro, J L

2015-03-01

The purpose of the current study is to compare the inactivation of Escherichia coli in wastewater effluents using conventional treatments (chlorination) and advanced oxidation processes (AOPs) such as UV irradiation, hydrogen peroxide (H2O2)/solar irradiation, and photo-Fenton processes. In addition, an analysis of the operational costs of each treatment is carried out taking into account the optimal dosages of chemicals used. Total inactivation of bacteria (7.5 log) was achieved by means of chlorination and UV irradiation. However, bacterial regrowth was observed 6 hours after the completion of UV treatment, obtaining a disinfection value around 3 to 4 log. On the other hand, the combination H2O2/solar irradiation achieved a maximum inactivation of E. coli of 3.30 ± 0.35 log. The photo-Fenton reaction achieved a level of inactivation of 4.87 ± 0.10 log. The order of disinfection, taking into account the reagent/cost ratio of each treatment, is as follows: chlorination > UV irradiation > photo-Fenton > H2O2/sunlight irradiation.

Combining micelle-clay sorption to solar photo-Fenton processes for domestic wastewater treatment.

PubMed

Brienza, Monica; Nir, Shlomo; Plantard, Gael; Goetz, Vincent; Chiron, Serge

2018-06-08

A tertiary treatment of effluent from a biological domestic wastewater treatment plant was tested by combining filtration and solar photocatalysis. Adsorption was carried out by a sequence of two column filters, the first one filled with granular activated carbon (GAC) and the second one with granulated nano-composite of micelle-montmorillonite mixed with sand (20:100, w/w). The applied solar advanced oxidation process was homogeneous photo-Fenton photocatalysis using peroxymonosulfate (PMS) as oxidant agent. This combination of simple, robust, and low-cost technologies aimed to ensure water disinfection and emerging contaminants (ECs, mainly pharmaceuticals) removal. The filtration step showed good performances in removing dissolved organic matter and practically removing all bacteria such as Escherichia coli and Enterococcus faecalis from the secondary treated water. Solar advanced oxidation processes were efficient in elimination of trace levels of ECs. The final effluent presented an improved sanitary level with acceptable chemical and biological characteristics for irrigation.

Natural soil mediated photo Fenton-like processes in treatment of pharmaceuticals: Batch and continuous approach.

PubMed

Changotra, Rahil; Rajput, Himadri; Dhir, Amit

2017-12-01

This paper manifests the potential viability of soil as a cost-free catalyst in photo-Fenton-like processes for treating pharmaceuticals at large scale. Naturally available soil without any cost intensive modification was utilized as a catalyst to degrade pharmaceuticals, specifically ornidazole (ORZ) and ofloxacin (OFX). Soil was characterized and found enriched with various iron oxides like hematite, magnetite, goethite, pyrite and wustite, which contributes toward enhanced dissolution of Fe 3+ than Fe 2+ in the aqueous solution resulting in augmented rate of photo-Fenton reaction. The leached iron concentration in solution was detected during the course of experiments. The degradation of ORZ and OFX was assessed in solar induced batch experiments using H 2 O 2 as oxidant and 95% ORZ and 92% OFX removal was achieved. Elevated efficiencies were achieved due to Fe 2+ /Fe 3+ cycling, producing more hydroxyl radical leading to the existence of homogeneous and heterogeneous reactions simultaneously. The removal efficiency of solar photo-Fenton like process was also compared to photo-Fenton process with different irradiation sources (UV-A and UV-B) and were statistically analysed. Continuous-scale studies were conducted employing soil either in the form of soil beads or as a thin layer spread on the surface of baffled reactor. Soil beads were found to have satisfactory reusability and stability. 84 and 79% degradation of ORZ and OFX was achieved using soil as thin layer while with soil beads 71 and 68% degradation, respectively. HPLC and TOC study confirmed the efficient removal of both the compounds. Toxicity assessment demonstrates the inexistence of toxic intermediates during the reaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electrochemical advanced oxidation for cold incineration of the pharmaceutical ranitidine: mineralization pathway and toxicity evolution.

PubMed

Olvera-Vargas, Hugo; Oturan, Nihal; Brillas, Enric; Buisson, Didier; Esposito, Giovanni; Oturan, Mehmet A

2014-12-01

Ranitidine (RNTD) is a widely prescribed histamine H2-receptor antagonist whose unambiguous presence in water sources appointed it as an emerging pollutant. Here, the degradation of 0.1 mM of this drug in aqueous medium was studied by electrochemical advanced oxidation processes (EAOPs) like anodic oxidation with electrogenerated H2O2 and electro-Fenton using Pt/carbon-felt, BDD/carbon-felt and DSA-Ti/RuO2–IrO2/carbon-felt cells. The higher oxidation power of the electro-Fenton process using a BDD anode was demonstrated. The oxidative degradation of RNTD by the electrochemically generated OH radicals obeyed a pseudo-first order kinetics. The absolute rate constant for its hydroxylation reaction was 3.39 × 109 M−1 s−1 as determined by the competition kinetics method. Almost complete mineralization of the RNTN solution was reached by using a BDD anode in both anodic oxidation with electrogenerated H2O2 and electro-Fenton processes. Up to 11 cyclic intermediates with furan moiety were detected from the degradation of RNTD, which were afterwards oxidized to short-chain carboxylic acids before their mineralization to CO2 and inorganic ions such as NH4+, NO3− and SO42−. Based on identified products, a plausible reaction pathway was proposed for RNTD mineralization. Toxicity assessment by the Microtox® method revealed that some cyclic intermediates are more toxic than the parent molecule. Toxicity was quickly removed following the almost total mineralization of the treated solution. Overall results confirm the effectiveness of EAOPs for the efficient removal of RNTD and its oxidation by-products from water.

Application of Electro-Fenton Technology to Remediation of Polluted Effluents by Self-Sustaining Process

PubMed Central

Fernández de Dios, Maria Ángeles; Iglesias, Olaia; Pazos, Marta; Sanromán, Maria Ángeles

2014-01-01

The applicability of electro-Fenton technology to remediation of wastewater contaminated by several organic pollutants such as dyes and polycyclic aromatic hydrocarbons has been evaluated using iron-enriched zeolite as heterogeneous catalyst. The electro-Fenton technology is an advanced oxidation process that is efficient for the degradation of organic pollutants, but it suffers from the high operating costs due to the need for power investment. For this reason, in this study microbial fuel cells (MFCs) were designed in order to supply electricity to electro-Fenton processes and to achieve high treatment efficiency at low cost. Initially, the effect of key parameters on the MFC power generation was evaluated. Afterwards, the degradation of Reactive Black 5 dye and phenanthrene was evaluated in an electro-Fenton reactor, containing iron-enriched zeolite as catalyst, using the electricity supplied by the MFC. Near complete dye decolourization and 78% of phenanthrene degradation were reached after 90 min and 30 h, respectively. Furthermore, preliminary reusability tests of the developed catalyst showed high degradation levels for successive cycles. The results permit concluding that the integrated system is adequate to achieve high treatment efficiency with low electrical consumption. PMID:24723828

Development and optimization of dark Fenton oxidation for the treatment of textile wastewaters with high organic load.

PubMed

Papadopoulos, A E; Fatta, D; Loizidou, M

2007-07-31

The examination of the effectiveness of the chemical oxidation using Fenton's reagent (H(2)O(2)/Fe(2+)) for the reduction of the organic content of wastewater generated from a textile industry has been studied. The experimental results indicate that the oxidation process leads to a reduction in the chemical oxygen demand (COD) concentration up to 45%. Moreover, the reduction is reasonably fast at the first stages of the process, since the COD concentration is decreased up to 45% within four hours and further treatment time does not add up to the overall decrease in the COD concentration (48% reduction within six hours). The maximum color removal achieved was 71.5%. In addition, the alterations observed in the organic matter during the development of the process, as indicated by the ratios of COD/TOC and BOD/COD and the oxidation state, show that a great part of the organic substances, which are not completely mineralized, are subjected to structural changes to intermediate organic by-products.

Water depollution using metal-organic frameworks-catalyzed advanced oxidation processes: A review.

PubMed

Sharma, Virender K; Feng, Mingbao

2017-09-28

This paper presents a review on the environmental applications of metal-organic frameworks (MOFs), which are inorganic-organic hybrid highly porous crystalline materials, prepared from metal ion/clusters and multidentate organic ligands. The emphases are made on the enhancement of the performance of advanced oxidation processes (AOPs) (photocatalysis, Fenton reaction methods, and sulfate radical (SO 4 - )-mediated oxidations) using MOFs materials. MOFs act as adsorption and light absorbers, leading to superior performance of photocatalytic processes. More recent examples of photocatalytic degradation of dyes are presented. Additionally, it is commonly shown that Fe-based MOFs exhibited excellent catalytic performance on the Fenton-based and SO 4 •- -mediated oxidations of organic pollutants (e.g., dyes, phenol and pharmaceuticals). The significantly enhanced generation of reactive species such as OH and/or SO 4 - by both homogeneous and heterogeneous catalysis was proposed as the possible mechanism for water depollution. Based on the existing literature, the challenge and future perspectives in MOF-based AOPs are addressed. Copyright © 2017 Elsevier B.V. All rights reserved.

Advanced oxidation process-biological system for wastewater containing a recalcitrant pollutant.

PubMed

Oller, I; Malato, S; Sánchez-Pérez, J A; Maldonado, M I; Gernjak, W; Pérez-Estrada, L A

2007-01-01

Two advanced oxidation processes (AOPs), ozonation and photo-Fenton, combined with a pilot aerobic biological reactor at field scale were employed for the treatment of industrial non-biodegradable saline wastewater (TOC around 200 mgL(-1)) containing a biorecalcitrant compound, alpha-methylphenylglycine (MPG), at a concentration of 500 mgL(-1). Ozonation experiments were performed in a 50-L reactor with constant inlet ozone of 21.9 g m(-3). Solar photo-Fenton tests were carried out in a 75-L pilot plant made up of four compound parabolic collector (CPC) units. The catalyst concentration employed in this system was 20 mgL(-1) of Fe2+ and the H2O2 concentration was kept in the range of 200-500mgL(-1). Complete degradation of MPG was attained after 1,020 min of ozone treatment, while only 195 min were required for photo-Fenton. Samples from different stages of both AOPs were taken for Zahn-Wellens biocompatibility tests. Biodegradability enhancement of the industrial saline wastewater was confirmed (>70% biodegradability). Biodegradable compounds generated during the preliminary oxidative processes were biologically mineralised in a 170-L aerobic immobilised biomass reactor (IBR). The global efficiency of both AOP/biological combined systems was 90% removal of an initial TOC of over 500 mgL(-1).

Comparative study of UV/TiO2, UV/ZnO and photo-Fenton processes for the organic reactive dye degradation in aqueous solution.

PubMed

Peternel, Igor T; Koprivanac, Natalija; Bozić, Ana M Loncarić; Kusić, Hrvoje M

2007-09-05

In this study advanced oxidation processes (AOPs), UV/TiO(2), UV/ZnO and photo-Fenton, were applied in order to degrade C.I. Reactive Red 45 (RR45) dye in aqueous solution. The effects of key operating parameters, such as initial pH, catalyst and hydrogen peroxide dosage as well as the effect of initial dye concentration on decolorization and mineralization extents were studied. Primary objective was to determine the optimal conditions for each of the processes. The influence of added zeolite on the process efficiency was also studied. UV/vis spectrophotometric and total organic carbon (TOC) measurements were performed for determination of decolorization and mineralization extents. It has been found that photo-Fenton process was the most efficient with 74.2% TOC removal and complete color removal achieved after a 1h treatment.

Spent caustic oxidation using electro-generated Fenton's reagent in a batch reactor.

PubMed

Rodriguez, Nicolas; Hansen, Henrik K; Nunez, Patricio; Guzman, Jaime

2008-07-01

This work shows the results of four Electro-Fenton laboratory tests to reduce the chemical oxygen demand (COD) in spent caustic solutions. The treatment consisted of (i) a pH reduction followed by (ii) an Electro-Fenton process, which was analyzed in this work. The Fenton's reagent was produced in a specially designed reactor, where the waste stream flowed through a labyrinth made by ferrous plates. These plates acted as sacrificial anodes-releasing Fe(2 +) cations to the solution, where H(2)O(2) was also added. The Electro-Fenton process was analyzed varying the ferrous ion concentration ([Fe(+ 2)]), the spent caustic's initial temperature and the initial pH. Close to 95% removal of COD (from 8800 mg L(- 1)) was achieved at a pH of 4, a temperature of 40 degrees C and 100 mg L(- 1) of Fe(+ 2) (applying 1 A). Two models were considered to simulate the behavior of the reactor considering (i) axial dispersion and (ii) kinetic rate, respectively. The model that was based on kinetics, proved to be the slightly closest fit to the experimental values.

Application of electrochemical advanced oxidation processes to the mineralization of the herbicide diuron.

PubMed

Pipi, Angelo R F; Sirés, Ignasi; De Andrade, Adalgisa R; Brillas, Enric

2014-08-01

Here, solutions with 0.185mM of the herbicide diuron of pH 3.0 have been treated by electrochemical advanced oxidation processes (EAOPs) like electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF) or solar PEF (SPEF). Trials were performed in stirred tank reactors of 100mL and in a recirculation flow plant of 2.5L using a filter-press reactor with a Pt or boron-doped diamond (BDD) anode and an air-diffusion cathode for H2O2 electrogeneration. Oxidant hydroxyl radicals were formed from water oxidation at the anode and/or in the bulk from Fenton's reaction between added Fe(2+) and generated H2O2. In both systems, the relative oxidation ability of the EAOPs increased in the sequence EO-H2O2

Integrated processes for produced water polishing: Enhanced flotation/sedimentation combined with advanced oxidation processes.

PubMed

Jiménez, Silvia; Micó, María M; Arnaldos, Marina; Ferrero, Enrique; Malfeito, Jorge J; Medina, Francisco; Contreras, Sandra

2017-02-01

In this study, bench scale dissolved air flotation (DAF) and settling processes have been studied and compared to a novel flotation technology based on the use of glass microspheres of limited buoyancy and its combination with conventional DAF, (Enhanced DAF or E-DAF). They were evaluated as pretreatments for advanced oxidation processes (AOPs) to polish produced water (PW) for reuse purposes. Settling and E-DAF without air injection showed adequate turbidity and oil and grease (O&G) removals, with eliminations higher than 87% and 90% respectively, employing 70 mg L -1 of FeCl 3 and 83 min of settling time, and 57.9 mg L -1 of FeCl 3 , 300 mg L -1 of microspheres and a flocculation rate of 40 rpm in the E-DAF process. A linear correlation was observed between final O&G concentration and turbidity after E-DAF. In order to polish the O&G content of the effluent even further, to remove soluble compounds as phenol and to take advantage of residual iron after these treatments, Fenton and photo-Fenton reactions were essayed. After 6 h of the Fenton reaction at pH 3, the addition of 1660 mg L -1 of H 2 O 2 and 133 mg L -1 of iron showed a maximum O&G elimination of 57.6% and a phenol removal up to 80%. Photo-Fenton process showed better results after 3 h, adding 600 mg L -1 of H 2 O 2 and 300 mg L -1 of iron, at pH 3, with a higher fraction of elimination of the O&G content (73.7%) and phenol (95%) compared to the conventional Fenton process. Copyright © 2016 Elsevier Ltd. All rights reserved.

ADVANTAGES/DISADVANTAGES FOR ISCO METHODS IN-SITU FENTON OXIDATION IN-SITU PERMANGANATE OXIDATION

EPA Science Inventory

The advantages and disadvantages of in-situ Fenton oxidation and in-situ permanganate oxidation will be presented. This presentation will provide a brief overview of each technology and a detailed analysis of the advantages and disadvantages of each technology. Included in the ...

Oxidative degradation of chlorophenol derivatives promoted by microwaves or power ultrasound: a mechanism investigation.

PubMed

Cravotto, Giancarlo; Binello, Arianna; Di Carlo, Stefano; Orio, Laura; Wu, Zhi-Lin; Ondruschka, Bernd

2010-03-01

Phenols are the most common pollutants in industrial wastewaters (particularly from oil refineries, resin manufacture, and coal processing). In the last two decades, it has become common knowledge that they can be effectively destroyed by nonconventional techniques such as power ultrasound (US) and/or microwave (MW) irradiation. Both techniques may strongly promote advanced oxidation processes (AOPs). The present study aimed to shed light on the effect and mechanism of US- and MW-promoted oxidative degradation of chlorophenols; 2,4-dichlorophenoxyacetic acid (2,4-D), a pesticide widespread in the environment, was chosen as the model compound. 2,4-D degradation by AOPs was carried out either under US (20 and 300 kHz) in aqueous solutions (with and without the addition of Fenton reagent) or solvent-free under MW with sodium percarbonate (SPC). All these reactions were monitored by gas chromatography-mass spectrometry (GC-MS) analysis and compared with the classical Fenton reaction in water under magnetic stirring. The same set of treatments was also applied to 2,4-dichlorophenol (2,4-DCP) and phenol, the first two products that occur a step down in the degradation sequence. Fenton and Fenton-like reagents were employed at the lowest active concentration. The effects of US and MW irradiation were investigated and compared with those of conventional treatments. Detailed mechanisms of Fenton-type reactions were suggested for 2,4-D, 2,4-DCP, and phenol, underlining the principal degradation products identified. MW-promoted degradation under solvent-free conditions with solid Fenton-like reagents (viz. SPC) is extremely efficient and mainly follows pyrolytic pathways. Power US strongly accelerates the degradation of 2,4-D in water through a rapid generation of highly reactive radicals; it does not lead to the formation of more toxic dimers. We show that US and MW enhance the oxidative degradation of 2,4-D and that a considerable saving of oxidants and cutting down of reaction times is thereby achieved. The results support the interpretation of previously published data and improve the understanding of the factors of direct degradation along different pathways. Oxidative pathways for 2,4-D, 2,4-DCP, and phenol were proposed by a careful monitoring of the reactions and detection of intermediates by GC-MS. The understanding of the factors that affect chlorophenols degradation along different pathways may facilitate the optimization of the treatment. Type of energy source (US or MW), power, and frequency to be applied could be designed in function of the operative scenario (amount of pollutant in soil, water, or oils).

Superiority of solar Fenton oxidation over TiO2 photocatalysis for the degradation of trimethoprim in secondary treated effluents.

PubMed

Michael, I; Hapeshi, E; Michael, C; Fatta-Kassinos, D

2013-01-01

The overall aim of this work was to examine the degradation of trimethoprim (TMP), which is an antibacterial agent, during the application of two advanced oxidation process (AOP) systems in secondary treated domestic effluents. The homogeneous solar Fenton process (hv/Fe(2+)/H2O2) and heterogeneous photocatalysis with titanium dioxide (TiO2) suspensions were tested. It was found that the degradation of TMP depends on several parameters such as the amount of iron salt and H2O2, concentration of TiO2, pH of solution, solar irradiation, temperature and initial substrate concentration. The optimum dosages of Fe(2+) and H2O2 for homogeneous ([Fe(2+)] = 5 mg L(-1), [H2O2] = 3.062 mmol L(-1)) and TiO2 ([TiO2] = 3 g L(-1)) for heterogeneous photocatalysis were established. The study indicated that the degradation of TMP during the solar Fenton process is described by a pseudo-first-order reaction and the substrate degradation during the heterogeneous photocatalysis by the Langmuir-Hinshelwood kinetics. The toxicity of the treated samples was evaluated using a Daphnia magna bioassay and was finally decreased by both processes. The results indicated that solar Fenton is more effective than the solar TiO2 process, yielding complete degradation of the examined substrate within 30 min of illumination and dissolved organic carbon (DOC) reduction of about 44% whereas the respective values for the TiO2 process were ∼70% degradation of TMP within 120 min of treatment and 13% DOC removal.

Decolorization and mineralization of Allura Red AC aqueous solutions by electrochemical advanced oxidation processes.

PubMed

Thiam, Abdoulaye; Sirés, Ignasi; Garrido, José A; Rodríguez, Rosa M; Brillas, Enric

2015-06-15

The decolorization and mineralization of solutions containing 230 mg L(-1) of the food azo dye Allura Red AC at pH 3.0 have been studied upon treatment by electrochemical oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF). Experiments were performed with a stirred tank reactor containing a boron-doped diamond (BDD) or Pt anode and an air-diffusion cathode to generate H2O2. The main oxidants were hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between H2O2 and added Fe(2+). The oxidation ability increased in the sequence EO-H2O2 < EF < PEF and faster degradation was always obtained using BDD. PEF process with BDD yielded almost total mineralization following similar trends in SO4(2-), ClO4(-) and NO3(-) media, whereas in Cl(-) medium, mineralization was inhibited by the formation of recalcitrant chloroderivatives. GC-MS analysis confirmed the cleavage of the −N=N− bond with formation of two main aromatics in SO4(2-) medium and three chloroaromatics in Cl(-) solutions. The effective oxidation of final oxalic and oxamic acids by BDD along with the photolysis of Fe(III)-oxalate species by UVA light accounted for the superiority of PEF with BDD. NH4(+), NO3(-) and SO4(2-) ions were released during the mineralization. Copyright © 2015 Elsevier B.V. All rights reserved.

Combined effects of Fenton peroxidation and CaO conditioning on sewage sludge thermal drying.

PubMed

Liu, Huan; Liu, Peng; Hu, Hongyun; Zhang, Qiang; Wu, Zhenyu; Yang, Jiakuan; Yao, Hong

2014-12-01

Joint application of Fenton's reagent and CaO can dramatically enhance sludge dewaterability, thus are also likely to affect subsequent thermal drying process. This study investigated the synergistic effects of the two conditioners on the thermal drying behavior of sewage sludge and the emission characteristics of main sulfur-/nitrogen-containing gases. According to the results, Fenton peroxidation combined with CaO conditioning efficiently promoted sludge heat transfer, reduced the amounts of both free and bound water, and created porous structure in solids to provide evaporation channels, thus producing significant positive effects on sludge drying performance. In this case, the required time for drying was shortened to one-third. Additionally, joint usage of Fenton's reagent and CaO did not increase the losses of organic matter during sludge drying process. Meanwhile, they facilitated the formation of sulfate and sulfonic acid/sulfone, leading to sulfur retention in dried sludge. Both of Fenton peroxidation and CaO conditioning promoted the oxidation, decomposition, and/or dissolution of protein and inorganic nitrogen in sludge pre-treatment. As a consequence, the emissions of sulfurous and nitrogenous gases from dewatered sludge drying were greatly suppressed. These indicate that combining Fenton peroxidation with CaO conditioning is a promising strategy to improve drying efficiency of sewage sludge and to control sulfur and nitrogen contaminants during sludge thermal drying process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of the mercaptobenzothiazole degradation by combined adsorption process and Fenton reaction using iron mining residue.

PubMed

Martins, Adriana Lau da Silva; Teixeira, Luís Alberto César; da Fonseca, Fabiana Valéria; Yokoyama, Lídia

2017-08-01

The present study investigated the degradation of mercaptobenzothiazole (MBT), evaluating homogeneous and heterogeneous systems. An iron mineral residue from the desliming step of iron mining was used as a source in the Fenton-like reaction (advanced oxidation process). A granulometric analysis of the residue was performed and yielded fractions with high hematite (Fe 2 O 3 ) and low quartz content in sieves from 74 to below 44 mm. In this particle size range, the hematite content from 58.9% to 67.4% and the Brunauer-Emmett-Teller area from 0.1345 to 1.3137 m 2  g -1 were obtained. The zeta potential curves as a function of pH were obtained for the residue, the MBT solution and mixtures thereof. The adsorption of MBT in the residue and its degradation through the Fenton-like reaction were investigated. Adsorption tests and the Fenton-like reaction were carried out, where the MBT species and the residue are oppositely charged, yielding, respectively, 10% MBT adsorption on the surface of the residue and 100% MBT degradation by the Fenton-like reaction at pH 3, hydrogen peroxide concentration of 25 mg L -1 , residue concentration of 3 g L -1 , 200 rpm and 25°C, from a 100 mg L -1 MBT solution. MBT degradation was found to occur mainly by the heterogeneous Fenton-like process.

Identification of intermediates, acute toxicity removal, and kinetics investigation to the Ametryn treatment by direct photolysis (UV254), UV254/H2O2, Fenton, and photo-Fenton processes.

PubMed

de Oliveira, Dirce Martins; Cavalcante, Rodrigo Pereira; da Silva, Lucas de Melo; Sans, Carme; Esplugas, Santiago; de Oliveira, Silvio Cesar; Junior, Amilcar Machulek

2018-02-09

This paper reports the degradation of 10 mg L -1 Ametryn solution with different advanced oxidation processes and by ultraviolet (UV 254 ) irradiation alone with the main objective of reducing acute toxicity and increase biodegradability. The investigated factors included Fe 2+ and H 2 O 2 concentrations. The effectiveness of the UV 254 and UV 254 /H 2 O 2 processes were investigated using a low-pressure mercury UV lamp (254 nm). Photo-Fenton process was explored using a blacklight blue lamp (BLB, λ = 365 nm). The UV 254 irradiation process achieved complete degradation of Ametryn solution after 60 min. The degradation time of Ametryn was greatly improved by the addition of H 2 O 2 . It is worth pointing out that a high rate of Ametryn removal was attained even at low concentrations of H 2 O 2 . The kinetic constant of the reaction between Ametryn and HO ● for UV 254 /H 2 O 2 was 3.53 × 10 8  L mol -1  s -1 . The complete Ametryn degradation by the Fenton and photo-Fenton processes was observed following 10 min of reaction for various combinations of Fe 2+ and H 2 O 2 under investigation. Working with the highest concentration (150 mg L -1 H 2 O 2 and 10 mg L -1 Fe 2+ ), around 30 and 70% of TOC removal were reached within 120 min of treatment by Fenton and photo-Fenton processes, respectively. Although it did not obtain complete mineralization, the intermediates formed in the degradation processes were hydroxylated and did not promote acute toxicity of Vibrio fischeri. Furthermore, a substantial improvement of biodegradability was obtained for all studied processes.

REPEATED REDUCTIVE AND OXIDATIVE TREATMENTS ON GRANULAR ACTIVATED CARBON

EPA Science Inventory

Fenton oxidation and Fenton oxidation preceded by reduction solutions were applied to granular activated carbon (GAC) to chemically regenerate the adsorbent. No adsorbate was present on the GAC so physicochemical effects from chemically aggressive regeneration of the carbon coul...

Effects of Fenton treatment on the properties of effluent organic matter and their relationships with the degradation of pharmaceuticals and personal care products.

PubMed

Li, Wei; Nanaboina, Venkateswarlu; Zhou, Qixing; Korshin, Gregory V

2012-02-01

This study examined effects of Fenton oxidation on trace level pharmaceuticals and personal care products (PPCPs) commonly occurring in wastewater. The tested PPCPs included acetaminophen, atenolol, atrazine, carbamazepine, metoprolol, dilantin, DEET, diclofenac, pentoxifylline, oxybenzone, caffeine, fluoxetine, gemfibrozil, ibuprofen, iopromide, naproxen, propranolol, sulfamethoxazole, bisphenol-A and trimethoprim. Transformations of effluent organic matter (EfOM) caused by Fenton oxidation were also quantified. All tested PPCPs, except atrazine and iopromide, were completely removed by Fenton treatment carried out using a 20mg/L Fe (II) concentration and a 2.5 H(2)O(2)/Fe (II) molar ratio. Up to 30% on the total carbon concentration was removed during Fenton treatment which was accompanied by the oxidation of EfOM molecules and formation of oxidation products such as oxalic, formic and acetic acids and, less prominently, formaldehyde, acetaldehyde, propionaldehyde and glycolaldehyde. The absorbance of EfOM treated with Fenton reagent at varying Fe (II) concentration and contact time underwent a consistent decrease. The relative decrease of EfOM absorbance was strongly and unambiguously correlated with the removal of all tested PPCPs. Copyright © 2011 Elsevier Ltd. All rights reserved.

Electro-oxidation of the dye azure B: kinetics, mechanism, and by-products.

PubMed

Olvera-Vargas, Hugo; Oturan, Nihal; Aravindakumar, C T; Paul, M M Sunil; Sharma, Virender K; Oturan, Mehmet A

2014-01-01

In this work, the electrochemical degradation of the dye azure B in aqueous solutions was studied by electrochemical advanced oxidation processes (EAOPs), electro-Fenton, and anodic oxidation processes, using Pt/carbon-felt and boron-doped diamond (BDD)/carbon-felt cells with H₂O₂ electrogeneration. The higher oxidation power of the electro-Fenton (EF) process using BDD anode was demonstrated. The oxidative degradation of azure B by the electrochemically generated hydroxyl radicals ((•)OH) follows a pseudo-first-order kinetics. The apparent rate constants of the oxidation of azure B by (•)OH were measured according to pseudo-first-order kinetic model. The absolute rate constant of azure B hydroxylation reaction was determined by competition kinetics method and found to be 1.19 × 10(9) M(-1) s(-1). It was found that the electrochemical degradation of the dye leads to the formation of aromatic by-products which are then oxidized to aliphatic carboxylic acids before their almost mineralization to CO₂ and inorganic ions (sulfate, nitrate, and ammonium). The evolution of the TOC removal and time course of short-chain carboxylic acids during treatment were also investigated.

Combination of heterogeneous Fenton-like reaction and photocatalysis using Co-TiO₂nanocatalyst for activation of KHSO₅ with visible light irradiation at ambient conditions.

PubMed

Chen, Qingkong; Ji, Fangying; Guo, Qian; Fan, Jianping; Xu, Xuan

2014-12-01

A novel coupled system using Co-TiO₂was successfully designed which combined two different heterogeneous advanced oxidation processes, sulfate radical based Fenton-like reaction (SR-Fenton) and visible light photocatalysis (Vis-Photo), for degradation of organic contaminants. The synergistic effect of SR-Fenton and Vis-Photo was observed through comparative tests of 50mg/L Rhodamine B (RhB) degradation and TOC removal. The Rhodamine B degradation rate and TOC removal were 100% and 68.1% using the SR-Fenton/Vis-Photo combined process under ambient conditions, respectively. Moreover, based on XRD, XPS and UV-DRS characterization, it can be deduced that tricobalt tetroxide located on the surface of the catalyst is the SR-Fenton active site, and cobalt ion implanted in the TiO₂lattice is the reason for the visible light photocatalytic activity of Co-TiO₂. Finally, the effects of the calcination temperature and cobalt concentration on the synergistic performance were also investigated and a possible mechanism for the synergistic system was proposed. This coupled system exhibited excellent catalytic stability and reusability, and almost no dissolution of Co²⁺ was found. Copyright © 2014. Published by Elsevier B.V.

Enhancement of Treatment Efficiency of Recalcitrant Wastewater Containing Textile Dyes Using a Newly Developed Iron Zeolite Socony Mobil-5 Heterogeneous Catalyst

PubMed Central

Ahmad, Mushtaq; Asghar, Anam; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

2015-01-01

Fenton oxidation, an advanced oxidation process, is an efficient method for the treatment of recalcitrant wastewaters. Unfortunately, it utilizes H2O2 and iron-based homogeneous catalysts, which lead to the formation of high volumes of sludge and secondary pollutants. To overcome these problems, an alternate option is the usage of heterogeneous catalyst. In this study, a heterogeneous catalyst was developed to provide an alternative solution for homogeneous Fenton oxidation. Iron Zeolite Socony Mobile-5 (Fe-ZSM-5) was synthesized using a new two-step process. Next, the catalyst was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis and tested against a model wastewater containing the azo dye Acid Blue 113. Results showed that the loading of iron particles reduced the surface area of the catalyst from 293.59 to 243.93 m2/g; meanwhile, the average particle size of the loaded material was 12.29 nm. Furthermore, efficiency of the developed catalyst was evaluated by performing heterogeneous Fenton oxidation. Taguchi method was coupled with principal component analysis in order to assess and optimize mineralization efficiency. Experimental results showed that under optimized conditions, over 99.7% degradation and 77% mineralization was obtained, with a 90% reduction in the consumption of the developed catalyst. Furthermore, the developed catalyst was stable and reusable, with less than 2% leaching observed under optimized conditions. Thus, the present study proved that newly developed catalyst has enhanced the oxidation process and reduced the chemicals consumption. PMID:26517827

A comparative study of ultrasonication, Fenton's oxidation and ferro-sonication treatment for degradation of carbamazepine from wastewater and toxicity test by Yeast Estrogen Screen (YES) assay.

PubMed

Mohapatra, D P; Brar, S K; Tyagi, R D; Picard, P; Surampalli, R Y

2013-03-01

A comparative study of ultrasonication (US), Fenton's oxidation (FO) and ferro-sonication (FS) (combination of ultrasonication and Fenton's oxidation) advanced oxidation processes (AOPs) for degradation of carbamazepine (CBZ) from wastewater (WW) is reported for the first time. CBZ is a worldwide used antiepileptic drug, found as a persistent emerging contaminant in many wastewater treatment plants (WWTPs) effluents and other aquatic environments. The oxidation treatments of WW caused an effective removal of the drug. Among the various US, FO and FS pre-treatments carried out, higher soluble chemical oxygen demand (SCOD) and soluble organic carbon (SOC) increment (63 to 86% and 21 to 34%, respectively) was observed during FO pre-treatment process, resulting in higher removal of CBZ (84 to 100%) from WW. Furthermore, analysis of by-products formed during US, FO and FS pre-treatment in WW was carried out by using laser diode thermal desorption-atmospheric pressure chemical ionization (LDTD-APCI) coupled to tandem mass spectrometry (MS/MS). LDTD-APCI-MS/MS analysis indicated formation of two by-products, such as epoxycarbamazepine and hydroxycarbamazepine due to the reaction of hydroxyl radicals (OH) with CBZ during the three types of pre-treatment processes. In addition, the estrogenic activity of US, FO and FS pre-treated sample with CBZ and its by-products was carried out by Yeast Estrogen Screen (YES) assay method. Based upon the YES test results, none of the pre-treated samples showed estrogenic activity. Copyright © 2012 Elsevier B.V. All rights reserved.

4-Hydroxyphenylacetic acid oxidation in sulfate and real olive oil mill wastewater by electrochemical advanced processes with a boron-doped diamond anode.

PubMed

Flores, Nelly; Cabot, Pere Lluís; Centellas, Francesc; Garrido, José Antonio; Rodríguez, Rosa María; Brillas, Enric; Sirés, Ignasi

2017-01-05

The degradation of 4-hydroxyphenylacetic acid, a ubiquitous component of olive oil mill wastewater (OOMW), has been studied by anodic oxidation with electrogenerated H 2 O 2 (AO-H 2 O 2 ), electro-Fenton (EF) and photoelectro-Fenton (PEF). Experiments were performed in either a 0.050M Na 2 SO 4 solution or a real OOMW at pH 3.0, using a cell with a boron-doped diamond (BDD) anode and an air-diffusion cathode for H 2 O 2 generation. Hydroxyl radicals formed at the BDD surface from water oxidation in all processes and/or in the bulk from Fenton's reaction between added Fe 2+ and generated H 2 O 2 in EF and PEF were the main oxidants. In both matrices, the oxidation ability of the processes increased in the order AO-H 2 O 2

Enhancement of Treatment Efficiency of Recalcitrant Wastewater Containing Textile Dyes Using a Newly Developed Iron Zeolite Socony Mobil-5 Heterogeneous Catalyst.

PubMed

Ahmad, Mushtaq; Asghar, Anam; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

2015-01-01

Fenton oxidation, an advanced oxidation process, is an efficient method for the treatment of recalcitrant wastewaters. Unfortunately, it utilizes H2O2 and iron-based homogeneous catalysts, which lead to the formation of high volumes of sludge and secondary pollutants. To overcome these problems, an alternate option is the usage of heterogeneous catalyst. In this study, a heterogeneous catalyst was developed to provide an alternative solution for homogeneous Fenton oxidation. Iron Zeolite Socony Mobile-5 (Fe-ZSM-5) was synthesized using a new two-step process. Next, the catalyst was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis and tested against a model wastewater containing the azo dye Acid Blue 113. Results showed that the loading of iron particles reduced the surface area of the catalyst from 293.59 to 243.93 m2/g; meanwhile, the average particle size of the loaded material was 12.29 nm. Furthermore, efficiency of the developed catalyst was evaluated by performing heterogeneous Fenton oxidation. Taguchi method was coupled with principal component analysis in order to assess and optimize mineralization efficiency. Experimental results showed that under optimized conditions, over 99.7% degradation and 77% mineralization was obtained, with a 90% reduction in the consumption of the developed catalyst. Furthermore, the developed catalyst was stable and reusable, with less than 2% leaching observed under optimized conditions. Thus, the present study proved that newly developed catalyst has enhanced the oxidation process and reduced the chemicals consumption.

Electrochemical destruction of trans-cinnamic acid by advanced oxidation processes: kinetics, mineralization, and degradation route.

PubMed

Flores, Nelly; Thiam, Abdoulaye; Rodríguez, Rosa María; Centellas, Francesc; Cabot, Pere Lluís; Garrido, José Antonio; Brillas, Enric; Sirés, Ignasi

2017-03-01

Acidic solutions of trans-cinnamic acid at pH 3.0 have been comparatively treated by anodic oxidation with electrogenerated H 2 O 2 (AO-H 2 O 2 ), electro-Fenton (EF), and photoelectro-Fenton (PEF). The electrolytic experiments were carried out with a boron-doped diamond (BDD)/air-diffusion cell. The substrate was very slowly abated by AO-H 2 O 2 because of its low reaction rate with oxidizing • OH produced from water discharge at the BDD anode. In contrast, its removal was very rapid and at similar rate by EF and PEF due to the additional oxidation by • OH in the bulk, formed from Fenton's reaction between cathodically generated H 2 O 2 and added Fe 2+ . The AO-H 2 O 2 treatment yielded the lowest mineralization. The EF process led to persistent final products like Fe(III) complexes, which were quickly photolyzed upon UVA irradiation in PEF to give an almost total mineralization with 98 % total organic carbon removal. The effect of current density and substrate concentration on all the mineralization processes was examined. Gas chromatography-mass spectrometry (GC-MS) analysis of electrolyzed solutions allowed identifying five primary aromatics and one heteroaromatic molecule, whereas final carboxylic acids like fumaric, acetic, and oxalic were quantified by ion exclusion high-performance liquid chromatography (HPLC). From all the products detected, a degradation route for trans-cinnamic acid is proposed.

Exquisite Enzyme-Fenton Biomimetic Catalysts for Hydroxyl Radical Production by Mimicking an Enzyme Cascade.

PubMed

Zhang, Qi; Chen, Shuo; Wang, Hua; Yu, Hongtao

2018-03-14

Hydrogen peroxide (H 2 O 2 ) is a key reactant in the Fenton process. As a byproduct of enzymatic reaction, H 2 O 2 can be obtained via catalytical oxidation of glucose using glucose oxidase in the presence of O 2 . Another oxidation product (gluconic acid) can suitably adjust the microenvironmental pH contributing to the Fe 3+ /Fe 2+ cycle in the Fenton reaction. Enzymes are extremely efficient at catalyzing a variety of reactions with high catalytic activity, substrate specificity, and yields in living organisms. Inspired by the multiple functions of natural multienzyme systems, an exquisite nanozyme-modified α-FeOOH/porous carbon (PC) biomimetic catalyst constructed by in situ growth of glucose oxidase-mimicking Au nanoparticles and crystallization of adsorbed ferric ions within carboxyl into hierarchically PC is developed as an efficient enzyme-Fenton catalyst. The products (H 2 O 2 , ∼4.07 mmol·L -1 ) of the first enzymatic reaction are immediately used as substrates for the second Fenton-like reaction to generate the valuable • OH (∼96.84 μmol·L -1 ), thus mimicking an enzyme cascade pathway. α-FeOOH nanocrystals, attached by C-O-Fe bondings, are encapsulated into the mesoporous PC frameworks, facilitating the electron transfer between α-FeOOH and the PC support and greatly suppressing iron leaching. This study paves a new avenue for designing biomimetic enzyme-based Fenton catalysts mimicking a natural system for • OH production.

Acute toxicity and chemical evaluation of coking wastewater under biological and advanced physicochemical treatment processes.

PubMed

Dehua, Ma; Cong, Liu; Xiaobiao, Zhu; Rui, Liu; Lujun, Chen

2016-09-01

This study investigated the changes of toxic compounds in coking wastewater with biological treatment (anaerobic reactor, anoxic reactor and aerobic-membrane bioreactor, A1/A2/O-MBR) and advanced physicochemical treatment (Fenton oxidation and activated carbon adsorption) stages. As the biological treatment stages preceding, the inhibition effect of coking wastewater on the luminescence of Vibrio qinghaiensis sp. Nov. Q67 decreased. Toxic units (TU) of coking wastewater were removed by A1/A2/O-MBR treatment process, however approximately 30 % TU remained in the biologically treated effluent. There is a tendency that fewer and fewer residual organic compounds could exert equal acute toxicity during the biological treatment stages. Activated carbon adsorption further removed toxic pollutants of biologically treated effluent but the Fenton effluent increased acute toxicity. The composition of coking wastewater during the treatment was evaluated using the three-dimensional fluorescence spectra, gas chromatography-mass spectrometry (GC-MS). The organic compounds with high polarity were the main cause of acute toxicity in the coking wastewater. Aromatic protein-like matters in the coking wastewater with low biodegradability and high toxicity contributed mostly to the remaining acute toxicity of the biologically treated effluents. Chlorine generated from the oxidation process was responsible for the acute toxicity increase after Fenton oxidation. Therefore, the incorporation of appropriate advanced physicochemical treatment process, e.g., activated carbon adsorption, should be implemented following biological treatment processes to meet the stricter discharge standards and be safer to the environment.

IN-SITU FENTON OXIDATION: A CRITICAL ANALYSIS

EPA Science Inventory

In-situ Fenton oxidation (ISFO) is a rapidly emerging technology which involves the injection of hydrogen peroxide (H2O2) and other chemical reagents into the subsurface for the purpose of oxidizing and transforming contaminants. ISFO is being applied at an increasing number of ...

Mineralization of hetero bi-functional reactive dye in aqueous solution by Fenton and photo-Fenton reactions.

PubMed

Torrades, Francesc; García-Hortal, José Antonio; García-Montaño, Julia

2015-01-01

This study focused on the advanced oxidation of the hetero bi-functional reactive dye Sumifix Supra Yellow 3RF (CI Reactive Yellow 145) using dark Fenton and photo-Fenton conditions in a lab-scale experiment. A 2(3) factorial design was used to evaluate the effects of the three key factors: temperature, Fe(II) and H2O2 concentrations, for a dye concentration of 250 mg L(-1) with chemical oxygen demand (COD) of 172 mg L(-1) O2 at pH=3. The response function was the COD reduction. This methodology lets us find the effects and interactions of the studied variables and their roles in the efficiency of the treatment process. In the optimization, the correlation coefficients for the model (R2) were 0.948 and 0.965 for Fenton and photo-Fenton treatments, respectively. Under optimized reaction conditions: pH=3, temperature=298 K, [H2O2]=11.765 mM and [Fe(II)]=1.075 mM; 60 min of treatment resulted in a 79% and 92.2% decrease in COD, for the dye taken as the model organic compound, after Fenton and photo-Fenton treatments, respectively.

Removal of tyrosol from water by adsorption on carbonaceous materials and electrochemical advanced oxidation processes.

PubMed

Flores, Nelly; Sharif, Farbod; Yasri, Nael; Brillas, Enric; Sirés, Ignasi; Roberts, Edward P L

2018-06-01

This work compares the ability of physical and chemical treatments, namely adsorption and electrochemical advanced oxidation processes, to remove tyrosol from aqueous medium. Adsorption on graphene nanoplatelets (GNPs) performed much better than that with a graphite intercalation compound. Adsorption isotherms were found to follow the Freundlich model (R 2  = 0.96), which is characteristic of a chemisorption process. Successful electrochemical regeneration enables 5 successive adsorption/regeneration cycles before corrosion of GNPs occurs. Other typical aromatic contaminants that may coexist with tyrosol can be also adsorbed on GNPs. Percentage of regeneration efficiency of GNPs showed a higher affinity towards Lewis acids group compounds and a lower one towards Lewis base. The treatment of 100 mL of 0.723 mM tyrosol solutions in non-chlorinated and chlorinated matrices at pH 3.0 was carried out by electrochemical oxidation with electrogenerated H 2 O 2 (EO-H 2 O 2 ), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF). Trials were made with a BDD anode and an air-diffusion cathode at 10-30 mA cm -2 . Hydroxyl radicals formed at the anode from water oxidation and/or in the bulk from Fenton's reaction between added Fe 2+ and generated H 2 O 2 , along with active chlorine produced in chlorinated medium, were the main oxidants. Tyrosol concentration always decayed following a pseudo-first-order kinetics and its mineralization rose as EO-H 2 O 2  < EF < PEF, more rapidly in the chlorinated matrix. The potent photolysis of intermediates under UVA radiation explained the almost total mineralization achieved by PEF in the latter medium. The effect of current density and tyrosol content on the performance of all processes was examined. Copyright © 2018 Elsevier Ltd. All rights reserved.

Degradation of 2,4-dichlorophenol with a novel TiO2/Ti-Fe-graphite felt photoelectrocatalytic oxidation process.

PubMed

Zhao, Bao-xiu; Li, Xiang-zhong; Wang, Peng

2007-01-01

Degradation of 2,4-dichlorophenol (2,4-DCP) was studied in a novel three-electrode photoelectrocatalytic (PEC) integrative oxidation process, and the factors influencing the degradation rate, such as applied current, flow speed of O2, pH, adscititious voltage and initial 2,4-DCP concentration were investigated and optimized. H2O2 was produced nearby cathode and Fe2+ continuously generated from Fe anode in solution when current and O2 were applied, so, main reactions, H2O2-assisted TiO2 PEC oxidation and E-Fenton reaction, occurred during degradation of 2,4-DCP in this integrative system. The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process, while it was only 31% in E-Fenton process and 46% in H2O2-assisted TiO2 PEC process. So, it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect. By the investigation of pH, it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9.

Efficient mineralization of antibiotic ciprofloxacin in acid aqueous medium by a novel photoelectro-Fenton process using a microwave discharge electrodeless lamp irradiation.

PubMed

Wang, Aimin; Zhang, Yanyu; Zhong, Huihui; Chen, Yu; Tian, Xiujun; Li, Desheng; Li, Jiuyi

2018-01-15

In this study, a novel photoelectro-Fenton (PEF) process using microwave discharge electrodeless lamp (MDEL) as a UV irradiation source was developed for the removal of antibiotic ciprofloxacin (CIP) in water. Comparative degradation of 200mgL -1 CIP was studied by direct MDEL photolysis, anodic oxidation (AO), AO in presence of electrogenerated H 2 O 2 (AO-H 2 O 2 ), AO-H 2 O 2 under MDEL irradiation (MDEL-AO-H 2 O 2 ), electro-Fenton (EF) and MDEL-PEF processes. Higher oxidation power was found in the sequence: MDEL photolysis < AO < AO-H 2 O 2 < MDEL-AO-H 2 O 2 < EF < MDEL-PEF. Effects of current density, pH, initial Fe 2+ concentration and initial CIP concentration on TOC removal in MDEL-PEF process were examined, and the optimal conditions were ascertained. The releases of three inorganic ions (F - , NH 4 + and NO 3 - ) and two carboxylic acids (oxalic and formic acids) were qualified. Seven aromatic intermediates mainly generated from hydroxylation, dealkylation and defluorination of CIP were detected by UPLC-QTOF-MS/MS technology. Therefore, plausible degradation sequences for CIP degradation in MDEL-PEF process including all detected products were proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficient conversion of dimethylarsinate into arsenic and its simultaneous adsorption removal over FeCx/N-doped carbon fiber composite in an electro-Fenton process.

PubMed

Lan, Huachun; Li, Jianfei; Sun, Meng; An, Xiaoqiang; Hu, Chengzhi; Liu, Ruiping; Liu, Huijuan; Qu, Jiuhui

2016-09-01

In this study, a FeCx/N-doped carbon fiber composite (FeCx/NCNFs) was developed via an electrospinning method. According to the characterization results of XRD, TEM and XPS, FeCx (a mixture of Fe7C3 and Fe3C) was either embedded in or attached to the NCNFs. It was used for the first time as a catalyst for dimethylarsinate (DMA) degradation and as an absorbent for inorganic arsenic (As (V)), with degradation and adsorption occurring simultaneously, in an electro-Fenton process. The effects of catalyst dosage, initial DMA concentration, solution pH, and applied current on the treatment efficiency and the corresponding H2O2 generation were systematically investigated. The results showed that DMA could be efficiently oxidized into As(V). 96% of DMA was degraded after reaction time of 360 min and the residual As(V) concentration in solution was below the allowable limit of 0.01 mg/L under the optimum treatment conditions. Based on an ESR and radical scavenger experiment, OH was proven to be the sole reactive oxygen species involved in the degradation process of DMA. DMA was oxidized to MMA as the primary oxidation product, which was subsequently oxidized to inorganic arsenic, As (V). TOC was also efficiently removed at the same time. The DMA removal mechanism for simultaneous degradation of dimethylarsinate and adsorption of arsenic over FeCx/NCNFs in the electro-Fenton process was also proposed based on the experimental results. Copyright © 2016. Published by Elsevier Ltd.

Degradation of the cytostatic 5-Fluorouracil in water by Fenton and photo-assisted oxidation processes.

PubMed

Governo, Mariana; Santos, Mónica S F; Alves, Arminda; Madeira, Luís M

2017-01-01

Cytostatics are part of the forefront research topics due to their high prescription, high toxicity, and the lack of effective solutions to stop their entrance and spread in the environment. Among them, 5-Fluorouracil (5-Fu) has received particular attention because is one of the most prescribed active substances in chemotherapy worldwide. The degradation of 5-Fu by advanced oxidation processes (AOPs) is a poorly addressed topic, and this work brings valuable inputs concerning this matter. Herein, the efficacy of Fenton's process in the degradation of 5-Fu is explored for the first time; the study of the main variables and its successful application to the treatment of real wastewaters is demonstrated. Moreover, hydrogen peroxide-based and photo-assisted techniques (direct photolysis, photodegradation with H 2 O 2 and photo-Fenton) are also investigated for purposes of comparison. Under the best operation conditions obtained (T = 30 °C, [Fe 2+ ] 0  = 0.5 mM; [H 2 O 2 ] 0  = 240 mM and pH = 3 for [5-Fu] 0  = 0.38 mM), 5-Fu was completely eliminated after 2 h of Fenton's reaction and about 50 % of mineralization was reached after 8 h. The best performance was obtained by the photo-Fenton process, with 5-Fu mineralization level as high as 67 %, using an iron dose within the legal limits required for direct water discharge. Toxicity (towards Vibrio fischeri) of the effluents that resulted from the application of the above-mentioned AOPs was also evaluated; it was found that the degradation products generated from the photo-assisted processes are less toxic than the parent compound, putting into evidence the relevance of such technologies for degradation of cytostatics like 5-Fu.

Effect of a solar Fered-Fenton system using a recirculation reactor on biologically treated landfill leachate.

PubMed

Ye, Zhihong; Zhang, Hui; Yang, Lin; Wu, Luxue; Qian, Yue; Geng, Jinyao; Chen, Mengmeng

2016-12-05

The effects of electrochemical oxidation (EO), Fered-Fenton and solar Fered-Fenton processes using a recirculation flow system containing an electrochemical cell and a solar photo-reactor on biochemically treated landfill leachate were investigated. The most successful method was solar Fered-Fenton which achieved 66.5% COD removal after 120min treatment utilizing the optimum operating conditions of 47mM H2O2, 0.29mM Fe(2+), pH0 of 3.0 and a current density of 60mA/cm(2). The generation of hydroxyl radicals (OH) are mainly from Fered-Fenton process, which is enhanced by the introduction of renewable solar energy. Moreover, Fe(2+)/chlorine and UV/chlorine processes taking place in this system also result in additional production of OH due to the relatively high concentration of chloride ions contained in the leachate. The energy consumption was 74.5kWh/kg COD and the current efficiency was 36.4% for 2h treatment. In addition, the molecular weight (MW) distribution analysis and PARAFAC analysis of excitation emission matrix (EEM) fluorescence spectroscopy for different leachate samples indicated that the organics in the leachate were significantly degraded into either small molecular weight species or inorganics. Copyright © 2016 Elsevier B.V. All rights reserved.

Environmental assessment of different advanced oxidation processes applied to a bleaching Kraft mill effluent.

PubMed

Muñoz, Iván; Rieradevall, Joan; Torrades, Francesc; Peral, José; Domènech, Xavier

2006-01-01

Different advanced oxidation processes (AOPs) have been applied to remove the organic carbon content of a paper mill effluent originating from the Kraft pulp bleaching process. The considered AOPs were: TiO(2)-mediated heterogeneous photocatalysis, TiO(2)-mediated heterogeneous photocatalysis assisted with H(2)O(2), TiO(2)-mediated heterogeneous photocatalysis coupled with Fenton, photo-Fenton, ozonation and ozonation with UV-A light irradiation. The application of the selected AOPs all resulted in a considerable decrease in dissolved organic carbon (DOC) content with variable treatment efficiencies depending upon the nature/type of the applied AOP. A Life Cycle Assessment (LCA) study was used as a tool to compare the different AOPs in terms of their environmental impact. Heterogeneous photocatalysis coupled with the Fenton's reagent proved to have the lowest environmental impact accompanied with a moderate-to-high DOC removal rate. On the other hand, heterogeneous photocatalysis appeared to be the worst AOP both in terms of DOC abatement rate and environmental impact. For the studied AOPs, LCA has indicated that the environmental impact was attributable to the high electrical energy (power) consumption necessary to run a UV-A lamp or to produce ozone.

Degradation and ecotoxicity of dye Reactive Black 5 after reductive-oxidative process : Environmental Science and Pollution Research.

PubMed

Cuervo Lumbaque, Elisabeth; Gomes, Monike Felipe; Da Silva Carvalho, Vanessa; de Freitas, Adriane Martins; Tiburtius, Elaine Regina Lopes

2017-03-01

This research paper describes the study of a reduction-oxidation system using commercial steel wool (Fe 0 ) and H 2 O 2 for degradation of the dye Reactive Black 5 and aromatic compounds in water. The reductive process alone allowed the almost complete removal of color (97 ± 1 %) after 60 min of reaction. The decrease in spectral area (λ = 599 nm) associated with the chromophore group indicates breakage of the azo bonds. Moreover, the significant change in UV spectra can be associated with the formation of aromatic amines. Regarding the transformation products, a spectrophotometric method based on the diazotization reaction was employed to identify aromatic amines after reductive process, using sulfanilic acid as a model of aromatic amines. In addition, association with Fenton reagents improved the efficiency in the system with 93 ± 1 % degradation of intermediates formed during the reductive process. Ecotoxicological analysis revealed that the dye solution, after the reductive and oxidative processes, was not toxic to Lactuca sativa seeds. For Daphnia magna, the EC 50 (%) values observed revealed that dye solution has an EC 50 (%) = 74.1 and after reductive process, the toxicity increased (EC 50 (%) = 63.5), which might be related to the formation of aromatic amines. However, after the Fenton process, the EC 50 (%) was >100. These results demonstrated that the Fenton reaction using steel wool as an iron source was very efficient to decrease color, aromatic transformation products, and the ecotoxicity of Reactive Black 5 in solution.

Constructing Solid-Gas-Interfacial Fenton Reaction over Alkalinized-C3N4 Photocatalyst To Achieve Apparent Quantum Yield of 49% at 420 nm.

PubMed

Li, Yunxiang; Ouyang, Shuxin; Xu, Hua; Wang, Xin; Bi, Yingpu; Zhang, Yuanfang; Ye, Jinhua

2016-10-03

Efficient generation of active oxygen-related radicals plays an essential role in boosting advanced oxidation process. To promote photocatalytic oxidation for gaseous pollutant over g-C 3 N 4 , a solid-gas interfacial Fenton reaction is coupled into alkalinized g-C 3 N 4 -based photocatalyst to effectively convert photocatalytic generation of H 2 O 2 into oxygen-related radicals. This system includes light energy as power, alkalinized g-C 3 N 4 -based photocatalyst as an in situ and robust H 2 O 2 generator, and surface-decorated Fe 3+ as a trigger of H 2 O 2 conversion, which attains highly efficient and universal activity for photodegradation of volatile organic compounds (VOCs). Taking the photooxidation of isopropanol as model reaction, this system achieves a photoactivity of 2-3 orders of magnitude higher than that of pristine g-C 3 N 4 , which corresponds to a high apparent quantum yield of 49% at around 420 nm. In-situ electron spin resonance (ESR) spectroscopy and sacrificial-reagent incorporated photocatalytic characterizations indicate that the notable photoactivity promotion could be ascribed to the collaboration between photocarriers (electrons and holes) and Fenton process to produce abundant and reactive oxygen-related radicals. The strategy of coupling solid-gas interfacial Fenton process into semiconductor-based photocatalysis provides a facile and promising solution to the remediation of air pollution via solar energy.

The Role of Ultrasound on Advanced Oxidation Processes.

PubMed

Babu, Sundaram Ganesh; Ashokkumar, Muthupandian; Neppolian, Bernaurdshaw

2016-10-01

This chapter describes the use of ultrasound in remediation of wastewater contaminated with organic pollutants in the absence and presence of other advanced oxidation processes (AOPs) such as sonolysis, sono-ozone process, sonophotocatalysis, sonoFenton systems and sonophoto-Fenton methods in detail. All these methods are explained with the suitable literature illustrations. In most of the cases, hybrid AOPs (combination of ultrasound with one or more AOPs) resulted in superior efficacy to that of individual AOP. The advantageous effects such as additive and synergistic effects obtained by operating the hybrid AOPs are highlighted with appropriate examples. It is worth to mention here that the utilization of ultrasound is not only restricted in preparation of modern active catalysts but also extensively used for the wastewater treatment. Interestingly, ultrasound coupled AOPs are operationally simple, efficient, and environmentally benign, and can be readily applied for large scale industrial processes which make them economically viable.

Utilizing solar energy for the purification of olive mill wastewater using a pilot-scale photocatalytic reactor after coagulation-flocculation.

PubMed

Michael, I; Panagi, A; Ioannou, L A; Frontistis, Z; Fatta-Kassinos, D

2014-09-01

This study investigated the application of a solar-driven advanced oxidation process (solar Fenton) combined with previous coagulation/flocculation, for the treatment of olive mill wastewater (OMW) at a pilot scale. Pre-treatment by coagulation/flocculation using FeSO4·7H2O (6.67 g L(-1)) as the coagulant, and an anionic polyelectrolyte (FLOCAN 23, 0.287 g L(-1)) as the flocculant, was performed to remove the solid content of the OMW. The solar Fenton experiments were carried out in a compound parabolic collector pilot plant, in the presence of varying doses of H2O2 and Fe(2+). The optimization of the oxidation process, using reagents at low concentrations ([Fe(2+)] = 0.08 g L(-1); [H2O2] = 1 g L(-1)), led to a high COD removal (87%), while the polyphenolic fraction, which is responsible for the biorecalcitrant and/or toxic properties of OMW, was eliminated. A kinetic study using a modified pseudo first-order kinetic model was performed in order to determine the reaction rate constants. This work evidences also the potential use of the solar Fenton process at the inherent pH of the OMW, yielding only a slightly lower COD removal (81%) compared to that obtained under acidic conditions. Moreover, the results demonstrated the capacity of the applied advanced process to reduce the initial OMW toxicity against the examined plant species (Sorghum saccharatum, Lepidium sativum, Sinapis alba), and the water flea Daphnia magna. The OMW treated samples displayed a varying toxicity profile for each type of organism and plant examined in this study, a fact that can potentially be attributed to the varying oxidation products formed during the process applied. Finally, the overall cost of solar Fenton oxidation for the treatment of 50 m(3) of OMW per day was estimated to be 2.11 € m(-3). Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhanced hydroxyl radical production by dihydroxybenzene-driven Fenton reactions: implications for wood biodegradation.

PubMed

Contreras, David; Rodríguez, Jaime; Freer, Juanita; Schwederski, Brigitte; Kaim, Wolfgang

2007-09-01

Brown rot fungi degrade wood, in initial stages, mainly through hydroxyl radicals (.OH) produced by Fenton reactions. These Fenton reactions can be promoted by dihydroxybenzenes (DHBs), which can chelate and reduce Fe(III), increasing the reactivity for different substrates. This mechanism allows the extensive degradation of carbohydrates and the oxidation of lignin during wood biodegradation by brown rot fungi. To understand the enhanced reactivity in these systems, kinetics experiments were carried out, measuring .OH formation by the spin-trapping technique of electron paramagnetic resonance spectroscopy. As models of the fungal DHBs, 1,2-dihydroxybenzene (catechol), 2,3-dihydroxybenzoic acid and 3,4-dihydroxybenzoic acid were utilized as well as 1,2-dihydroxy-3,5-benzenedisulfonate as a non-Fe(III)-reducing substance for comparison. Higher amounts and maintained concentrations of .OH were observed in the driven Fenton reactions versus the unmodified Fenton process. A linear correlation between the logarithms of complex stability constants and the .OH production was observed, suggesting participation of such complexes in the radical production.

Winery wastewater treatment by a combined process: long term aerated storage and Fenton's reagent.

PubMed

Lucas, Marco S; Mouta, Maria; Pirra, António; Peres, José A

2009-01-01

The degradation of the organic pollutants present in winery wastewater was carried out by the combination of two successive steps: an aerobic biological process followed by a chemical oxidation process using Fenton's reagent. The main goal of this study was to evaluate the temporal characteristics of solids and chemical oxygen demand (COD) present in winery wastewater in a long term aerated storage bioreactor. The performance of different air dosage daily supplied to the biologic reactor, in laboratory and pilot scale, were examined. The long term hydraulic retention time, 11 weeks, contributed remarkably to the reduction of COD (about 90%) and the combination with the Fenton's reagent led to a high overall COD reduction that reached 99.5% when the mass ratio (R = H(2)O(2)/COD) used was equal to 2.5, maintaining constant the molar ratio H(2)O(2)/Fe(2+)=15.

Treatment of real effluents from the pharmaceutical industry: A comparison between Fenton oxidation and conductive-diamond electro-oxidation.

PubMed

Pérez, J F; Llanos, J; Sáez, C; López, C; Cañizares, P; Rodrigo, M A

2017-06-15

Wastewater produced in pharmaceutical manufacturing plants (PMPs), especially the one coming from organic-synthesis facilities, is characterized by its large variability due to the wide range of solvents and chemical reagents used in the different stages of the production of medicines. Normally, the toxicity of the organic compounds prevent the utilization of biological processes and more powerful treatments are needed becoming advanced oxidation processes (AOPs) a valid alternative. In this work, the efficiency in abatement of pollution by Fenton oxidation (FO) and conductive-diamond electro-oxidation (CDEO) are compared in the treatment of 60 real effluents coming from different processes carried out in a pharmaceutical facility, using standardized tests. In 80% of the samples, CDEO was found to be more efficient than FO and in the remaining 20%, coagulation was found to exhibit a great significance in the COD abatement mechanism during FO, pointing out the effectiveness of the oxidation promoted by the electrochemical technology. Mean oxidation state of carbon was found to be a relevant parameter to understand the behavior of the oxidation technologies. It varied inversely proportional to efficiency in FO and it showed practically no influence in the case of CDEO. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transformation characteristics of refractory pollutants in plugboard wastewater by an optimal electrocoagulation and electro-Fenton process.

PubMed

Zhao, Xu; Zhang, Baofeng; Liu, Huijuan; Chen, Fayuan; Li, Angzhen; Qu, Jiuhui

2012-05-01

The treatment of the plugboard wastewater was performed by an optimal electrocoagulation and electro-Fenton. The organic components with suspended fractions accounting for 30% COD were preferably removed via electrocoagulation at initial 5 min. In contrast, the removal efficiency was increased to 76% with the addition of H(2)O(2). The electrogenerated Fe(2+) reacts with H(2)O(2) and leads to the generation of (·)OH, which is responsible for the higher COD removal. However, overdosage H(2)O(2) will consume (·)OH generated in the electro-Fenton process and lead to the low COD removal. The COD removal efficiency decreased with the increased pH. The concentration of Fe(2+) ions was dependent on the solution pH, H(2)O(2) dosage and current density. The changes of organic characteristics in coagulation and oxidation process were differenced and evaluated using gel permeation chromatography, fluorescence excitation-emission scans and Fourier transform infrared spectroscopy. The fraction of the wastewater with aromatic structure and large molecular weight was decomposed into aliphatic structure and small molecular weight fraction in the electro-Fenton process. Copyright © 2012. Published by Elsevier Ltd.

Advanced oxidation processes for treatment of effluents from a detergent industry.

PubMed

Martins, Rui C; Silva, Adrián M T; Castro-Silva, Sérgio; Garção-Nunes, Paulo; Quinta-Ferreira, Rosa M

2011-07-01

Ozonation, catalytic ozonation, Fenton's and heterogeneous Fenton-like processes were investigated as possible pretreatments of a low biodegradable and highly toxic wastewater produced by a detergent industry. The presence of a Mn-Ce-O catalyst in ozonation enhances the biodegradability and improves the degradation at low pH values. However, a high content of carbonyl compounds adsorbed on the recovered solid indicates some limitations for real-scale application. A commercial Fe2O3-MnOx catalyst shows higher activity as well as higher stability concerning carbon adsorption, but the leaching of metals is larger than for Mn-Ce-O. Regarding the heterogeneous Fenton-like route with an Fe-Ce-O catalyst, even though a high activity and stability are attained, the intermediates are less biodegradable than the original compounds, indicating that the resulting effluent cannot be conducted to an activated sludge post-treatment. The highest enhancement of effluent biodegradability is obtained with the classic homogeneous Fenton's process, with the BOD5/COD ratio increasing from 0.32 to 0.80. This process was scaled up and the treated effluent is now safely directed to a municipal wastewater treatment plant.

Effect of advanced oxidation processes on the micropollutants and the effluent organic matter contained in municipal wastewater previously treated by three different secondary methods.

PubMed

Giannakis, Stefanos; Gamarra Vives, Franco Alejandro; Grandjean, Dominique; Magnet, Anoys; De Alencastro, Luiz Felippe; Pulgarin, César

2015-11-01

In this study, wastewater from the output of three different secondary treatment facilities (Activated Sludge, Moving Bed Bioreactor and Coagulation-Flocculation) present in the municipal wastewater treatment plant of Vidy, Lausanne (Switzerland), was further treated with various oxidation processes (UV, UV/H2O2, solar irradiation, Fenton, solar photo-Fenton), at laboratory scale. For this assessment, 6 organic micropollutants in agreement with the new environmental legislation requirements in Switzerland were selected (Carbamazepine, Clarithromycin, Diclofenac, Metoprolol, Benzotriazole, Mecoprop) and monitored throughout the treatment. Also, the overall removal of the organic load was assessed. After each secondary treatment, the efficiency of the AOPs increased in the following order: Coagulation-Flocculation < Activated Sludge < Moving Bed Bioreactor, in almost all cases. From the different combinations tested, municipal wastewater subjected to biological treatment followed by UV/H2O2 resulted in the highest elimination levels. Wastewater previously treated by physicochemical treatment demonstrated considerably inhibited micropollutant degradation rates. The degradation kinetics were determined, yielding: k (UV) < k (UV/H2O2) and k (Fenton) < k (solar irradiation) < k (photo-Fenton). Finally, the evolution of global pollution parameters (COD & TOC elimination) was followed and the degradation pathways for the effluent organic matter are discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Advanced oxidation of biorefractory organics in aqueous solution together with bioelectricity generation by microbial fuel cells with composite FO/GPEs

NASA Astrophysics Data System (ADS)

Fu, Bao-rong; Shen, Chao; Ren, Jing; Chen, Jia-yi; Zhao, Lin

2018-03-01

In this study, ferric oxide loading graphite particle electrodes (FO/GPEs) were prepared as cathode of a three-dimensional electrode MFC-Fenton system. The properties of the composite cathode were examined with higher surface area and more mesopores. FO/GPEs could work as both cathode and Fenton iron reagents, contributing to high oxidation activity and better performance of electricity generation. The application of FO/GPEs MFC-Fenton system on degrading p-nitrophenol presented high catalytic efficiency in a wide range of pH value. The removal of p-nitrophenol and TOC attained to about 85 % within 8 and 64 h at neutral pH, respectively. A neutral FO/GPEs MFC-Fenton oxidation mechanism was also proposed. Specifically, both the surface iron sites and dissolved iron ions catalyzed the decomposition of H2O2. As results, the generated hydroxyl radicals were used for p-nitrophenol degradation and the iron oxide was recycled.

Oxidative Degradation of Chlorophenolic Compounds with Modified-Fenton Process Using Pyrite as the Catalyst

NASA Astrophysics Data System (ADS)

Kantar, Cetin; Urken, Ozge; Oral, Ozlem; Kaplan, Iremsu; Ayman Oz, Nilgun

2017-04-01

Oxidative dehalogenation has been shown to be a viable and cost effective process for dealing with a particularly persistent class of contaminants (e.g., chlorophenolic compounds (CP)) often found in contaminated soil and ground water. Here, the degradation of various chlorophenolic compounds (e.g., 2-CP, 4-CP, 2,3-di CP, 2,4-di CP, 2,4,6-tri CP, 2,3,4,6-Tetra CP) was investigated by modified Fenton process using pyrite as source of Fe2+ (catalyst) . The effects of different parameters such as chlorophenol type, pH and chlorophenol, pyrite and H2O2 concentrations on the degradation kinetics of chlorophenols were studied in batch reactors. Our results show that while the rate of chloropehenol degradation increased with decreasing solution pH, no direct correlation was observed between H2O2 concentration and chlorophenol degradation, indicating a complex mechanism involved in CP degradation by modified Fenton process. The batch results also show that the CP degradation was highly dependent on CP type, the number and location of chloride ions in the structure. Overall, the results of this study suggest that pyrite can be effectively used in reactive treatment barriers for in-situ treatment of subsurface systems contaminated with chlorophenols.

Enhanced Fenton-like removal of nitrobenzene via internal microelectrolysis in nano zerovalent iron/activated carbon composite.

PubMed

Hu, Sihai; Wu, Yaoguo; Yao, Hairui; Lu, Cong; Zhang, Chengjun

2016-01-01

The efficiency of Fenton-like catalysis using nano zerovalent iron (nZVI) is limited by nZVI aggregation and activity loss due to inactive ferric oxide forming on the nZVI surface, which hinders electron transfer. A novel iron-carbon composite catalyst consisting of nZVI and granular activated carbon (GAC), which can undergo internal iron-carbon microelectrolysis spontaneously, was successfully fabricated by the adsorption-reduction method. The catalyst efficiency was evaluated in nitrobenzene (NB) removal via the Fenton-like process (H2O2-nZVI/GAC). The results showed that nZVI/GAC composite was good for dispersing nZVI on the surface of GAC, which permitted much better removal efficiency (93.0%) than nZVI (31.0%) or GAC (20.0%) alone. Moreover, iron leaching decreased from 1.28 to 0.58 mg/L after reaction of 240 min and the oxidation kinetic of the Fenton-like reaction can be described well by the second-order reaction kinetic model (R2=0.988). The composite catalyst showed sustainable catalytic ability and GAC performed as a medium for electron transfer in internal iron-carbon microelectrolysis to promote Fe2+ regeneration and Fe3+/Fe2+ cycles. Therefore, this study represents an important method to design a low cost and high efficiency Fenton-like catalyst in practical application.

Electro-fenton and photoelectro-fenton degradation of sulfanilic acid using a boron-doped diamond anode and an air diffusion cathode.

PubMed

El-Ghenymy, Abdellatif; Garrido, José Antonio; Centellas, Francesc; Arias, Conchita; Cabot, Pere Lluís; Rodríguez, Rosa María; Brillas, Enric

2012-04-05

The mineralization of sulfanilic acid has been studied by electro-Fenton (EF) and photoelectro-Fenton (PEF) reaction with UVA light using an undivided electrochemical cell with a boron-doped diamond (BDD) anode and an air diffusion cathode able to generate H(2)O(2). Organics were then oxidized by hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between generated H(2)O(2) and added Fe(2+). The UVA irradiation in PEF enhanced the production of hydroxyl radicals in the bulk, accelerating the removal of organics and photodecomposed intermediates like Fe(III)-carboxylate complexes. Partial decontamination of 1.39 mM sulfanilic acid solutions was achieved by EF until 100 mA cm(-2) at optimum conditions of 0.4 mM Fe(2+) and pH 3.0. The increase in current density and substrate content led to an almost total mineralization. In contrast, the PEF process was more powerful, yielding almost complete mineralization in less electrolysis time under comparable conditions. The kinetics for sulfanilic acid decay always followed a pseudo-first-order reaction. Hydroquinone and p-benzoquinone were detected as aromatic intermediates, whereas acetic, maleic, formic, oxalic, and oxamic acids were identified as generated carboxylic acids. NH(4)(+) ion was preferentially released in both treatments, along with NO(3)(-) ion in smaller proportion.

Pyrite nanoparticles as a Fenton-like reagent for in situ remediation of organic pollutants

PubMed Central

Losa-Adams, Elisabeth; F.-Dávila, Alfonso; Gago-Duport, Luis

2014-01-01

Summary The Fenton reaction is the most widely used advanced oxidation process (AOP) for wastewater treatment. This study reports on the use of pyrite nanoparticles and microparticles as Fenton reagents for the oxidative degradation of copper phthalocyanine (CuPc) as a representative contaminant. Upon oxidative dissolution in water, pyrite (FeS2) particles can generate H2O2 at their surface while simultaneously promoting recycling of Fe3+ into Fe2+ and vice versa. Pyrite nanoparticles were synthesized by the hot injection method. The use of a high concentration of precursors gave individual nanoparticles (diameter: 20 nm) with broader crystallinity at the outer interfaces, providing a greater number of surface defects, which is advantageous for generating H2O2. Batch reactions were run to monitor the kinetics of CuPc degradation in real time and the amount of H2O2. A markedly greater degradation of CuPc was achieved with nanoparticles as compared to microparticles: at low loadings (0.08 mg/L) and 20 h reaction time, the former enabled 60% CuPc removal, whereas the latter enabled only 7% removal. These results confirm that the use of low concentrations of synthetic nanoparticles can be a cost effective alternative to conventional Fenton procedures for use in wastewater treatment, avoiding the potential risks caused by the release of heavy metals upon dissolution of natural pyrites. PMID:24991522

Pyrite nanoparticles as a Fenton-like reagent for in situ remediation of organic pollutants.

PubMed

Gil-Lozano, Carolina; Losa-Adams, Elisabeth; F-Dávila, Alfonso; Gago-Duport, Luis

2014-01-01

The Fenton reaction is the most widely used advanced oxidation process (AOP) for wastewater treatment. This study reports on the use of pyrite nanoparticles and microparticles as Fenton reagents for the oxidative degradation of copper phthalocyanine (CuPc) as a representative contaminant. Upon oxidative dissolution in water, pyrite (FeS2) particles can generate H2O2 at their surface while simultaneously promoting recycling of Fe(3+) into Fe(2+) and vice versa. Pyrite nanoparticles were synthesized by the hot injection method. The use of a high concentration of precursors gave individual nanoparticles (diameter: 20 nm) with broader crystallinity at the outer interfaces, providing a greater number of surface defects, which is advantageous for generating H2O2. Batch reactions were run to monitor the kinetics of CuPc degradation in real time and the amount of H2O2. A markedly greater degradation of CuPc was achieved with nanoparticles as compared to microparticles: at low loadings (0.08 mg/L) and 20 h reaction time, the former enabled 60% CuPc removal, whereas the latter enabled only 7% removal. These results confirm that the use of low concentrations of synthetic nanoparticles can be a cost effective alternative to conventional Fenton procedures for use in wastewater treatment, avoiding the potential risks caused by the release of heavy metals upon dissolution of natural pyrites.

FENTON-DRIVEN REGENERATION OF GRANULAR ACTIVATED CARBON: A TECHNOLOGY OVERVIEW

EPA Science Inventory

A Fenton-driven mechanism for regenerating spent granular activated carbon (GAC) involves the combined, synergistic use of two reliable and well established treatment technologies - adsorption onto activated carbon and Fenton oxidation. During carbon adsorption treatment, enviro...

Assessment of Fenton's reagent and ozonation as pre-treatments for increasing the biodegradability of aqueous diethanolamine solutions from an oil refinery gas sweetening process.

PubMed

Durán-Moreno, A; García-González, S A; Gutiérrez-Lara, M R; Rigas, F; Ramírez-Zamora, R M

2011-02-28

The aim of this work was to evaluate the efficiency of three chemical oxidation processes for increasing the biodegradability of aqueous diethanolamine solutions (aqueous DEA solutions), to be used as pre-treatments before a biological process. The raw aqueous DEA solution, sourced from a sour gas sweetening plant at a Mexican oil refinery, was first characterized by standardized physico-chemical methods. Then experiments were conducted on diluted aqueous DEA solutions to test the effects of Fenton's reagent, ozone and ozone-hydrogen peroxide on the removal of some physicochemical parameters of these solutions. Lastly, biodegradability tests based on Dissolved Organic Carbon Die Away OECD301-A, were carried out on a dilution of the raw aqueous DEA solution and on the treated aqueous DEA solutions, produced by applying the best experimental conditions determined during the aforementioned oxidation tests. Experimental results showed that for aqueous DEA solutions treated with Fenton's reagent, the best degradation rate (70%) was obtained at pH 2.8, with Fe(2+) and H(2)O(2) at doses of 1000 and 10,000 mg/L respectively. In the ozone process, the best degradation (60%) was observed in aqueous DEA solution (100 mg COD/L), using 100 mg O(3)/L at pH 5. In the ozone-hydrogen peroxide process, no COD or DOC removals were observed. The diluted spent diethanolamine solution showed its greatest increase in biodegradability after a reaction period of 28 days when treated with Fenton's reagent, but after only 15 days in the case of ozonation. Copyright © 2011 Elsevier B.V. All rights reserved.

Easy solid-phase synthesis of pH-insensitive heterogeneous CNTs/FeS Fenton-like catalyst for the removal of antibiotics from aqueous solution.

PubMed

Ma, Jie; Yang, Mingxuan; Yu, Fei; Chen, Junhong

2015-04-15

We report a facile solid method to synthesize efficient carbon-based Fenton-like catalyst (CNTs/FeS) using as-prepared carbon nanotubes (APCNTs), which makes full use of the iron nanoparticles in APCNTs without needless purification. Furthermore, the CNTs/FeS was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric (TG) and other analysis techniques, and then the CNTs/FeS was used as a Fenton-like catalyst for removing ciprofloxacin from aqueous solution. Response Surface Methodology (RSM) was applied to find the effect of the reaction parameter and the optimum operating condition. Results shows the catalytic reaction had better suitability than previous studies in a wide range of pH values (pH 3-8) and the Fenton-like catalyst CNTs/FeS exhibits good catalytic activity for removing of antibiotic, which be attributed to the synergistic effect of adsorption-advanced oxidation and significantly improves efficiency of advanced oxidation. More importantly, the CNTs/FeS catalyst exhibit good regeneration performance and retains a high catalytic capacity (>75%) even after four reaction cycles. The catalytic mechanism were also studied further, the removal mechanism of ciprofloxacin by a CNTs/FeS heterogeneous Fenton-like process primarily involves three removal pathways occurring simultaneously: (a) adsorption removal by CNTs, (b) Fenton-like degradation catalyzed by FeS, (c) catalytic degradation by CNTs catalyst. And these actions also have synergistic effects for ciprofloxacin removal. Copyright © 2014 Elsevier Inc. All rights reserved.

Visible-light photo-Fenton oxidation of phenol with rGO-α-FeOOH supported on Al-doped mesoporous silica (MCM-41) at neutral pH: Performance and optimization of the catalyst.

PubMed

Wang, Ying; Liang, Mingxing; Fang, Jiasheng; Fu, Jun; Chen, Xiaochun

2017-09-01

In this study, α-FeOOH on reduced graphene oxide (rGO-α-FeOOH) supported on an Al-doped MCM-41 catalyst (RFAM) was optimized for the visible-light photo-Fenton oxidation of phenol at neutral pH. The stability of the catalysts, effect of bubbling aeration, and degradation intermediates were investigated. Results indicated that RFAM with a large Brunauer-Emmett-Teller (BET) area and mesoporous structure displayed excellent catalytic activity for the visible-light-driven (VLD) photo-Fenton process. Phenol degradation was well described by a pseudo-first-order reaction kinetics model. Raman analysis demonstrated that an rGO-α-FeOOH (RF) composite is formed during the ferrous-ion-induced self-assembly process. Al-MCM-41 could uniformly disperse RF nanosheets and promote the mobility and diffusion of matter. The activity of the main catalyst α-FeOOH was enhanced after the incorporation of rGO nanosheets. The α-FeOOH crystal in RFAM showed catalytic activity superior to those of Fe 3 O 4 and Fe 2 O 3 . The RFAM catalyst, with an optimal GO-Fe 2+ mass ratio of 2.33, exhibited a larger BET area, pore size, and pore volume, and thus exhibited high performance and energy utilization efficiency in the VLD photo-Fenton reaction with remarkable stability. Bubbling N 2 inhibited catalytic performance, while bubbling O 2 or air only slightly accelerated the phenol degradation. Visible light played an important role in accelerating the formation of reactive oxygen species (·OH) for the highly efficient phenol degradation. Analysis of degradation intermediates indicated a high phenol mineralization level and the formation of low-molecular-weight organic acids. This work would be helpful in providing an insight into a new type of catalyst assembly and a possible route to a promising heterogeneous catalyst applicable in the visible light photo-Fenton process for effective wastewater remediation at neutral pH. Copyright © 2017. Published by Elsevier Ltd.

Application of SBA-15 in Adsorption-Fenton Oxidation Process for Simultaneous Remediation of Dehp and As(iii)

NASA Astrophysics Data System (ADS)

Latorre, I.; Hwang, S.

2013-12-01

Di-2-ethylhexyl phthalate (DEHP) has been widely used as plasticizer in the manufacturing of polymeric materials to enhance flexibility, transparency and softness, particularly, in polyvinyl chloride (PVC) production. Several studies elucidated that DEHP could be linked to hepatocellular tumors and pre-term birth and may be a developmental and reproductive toxicant. Arsenic (As) contamination has been widespread in the environment and because of its toxicity and prevalence in nature; it also has become a significant environmental health concern. Most solid waste materials containing DEHP and As(III) are disposed of in landfills and may migrate to groundwater and soil environments representing a threat to human receptors. Therefore, the application of adsorption-Fenton oxidation process with Fe adsorbed to SBA-15 matrix was assessed for simultaneous remediation of DEHP and As(III). Three sequences were run to assess the regeneration efficiency of the SBA-15. A response surface methodology was employed to optimize adsorption and Fenton regeneration. Adsorption optimization was evaluated with regard to SBA-15 doses and the extent of As(III) and Fe concentrations. Optimization of Fenton regeneration, in addition, assessed initial H2O2 concentration. Global optimization for maximum reduction of DEHP and As(III) was performed by D-Optimal. Highest adsorption of DEHP (90-95%) and As (40-95%) into the SBA-15 was predicted at 1.16 mM Fe, 18.74 mg SBA-15 and 3.71 mg/L As(III). Highest reduction of As (78-99%) and DEHP (90-97%) was predicted with 0.50 mM Fe, 22 mg SBA-15, 3.02 mg/L As(III) and 22.50 mM H2O2. Global optimal treatments were validated and SBA-15 regenerated material was characterized via SEM and XPS. The efficiency of DEHP and As(III) remediation by adsorption-Fenton oxidation process, applying optimal treatment combinations, was evaluated using leachate from a lab scale bioreactor monofill (i.e., filled with PVC materials). Capability of As(III) and DEHP adsorption into SBA-15 was affected by the preferentiality adsorption of Fe and other compounds present in the monofill leachate.

Fenton-Driven Regeneration of MTBE-spent Granular Activated Carbon

EPA Science Inventory

Fenton-driven regeneration of Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves the combined, synergistic use of two treatment technologies: adsorption of organic chemicals onto activated carbon and Fenton-driven oxidation regeneration of the spent-GAC...

Fenton- and Persulfate-driven Regeneration of Contaminant-spent Granular Activated Carbon

EPA Science Inventory

Fenton- or persulfate-driven chemical oxidation regeneration of spent granular activated carbon (GAC) involves the combined, synergistic use of two treatment technologies: adsorption of organic chemicals onto GAC and chemical oxidation regeneration of the spent-GAC. Environmental...

Solar photoassisted advanced oxidation process of azo dyes.

PubMed

Prato-Garcia, D; Buitrón, G

2009-01-01

Advanced oxidation processes assisted with natural solar radiation in CPC type reactors (parabolic collector compound), was applied for the degradation of three azo dyes: acid orange (AO7), acid red 151 (AR151) and acid blue 113 (AB113). Fenton, Fenton like and ferrioxalate-type complexes showed to be effective for degrade the azo linkage and moieties in different extensions. Initially, the best dose of reagents (Fe(3 + )-H(2)O(2)) was determined through a factorial experimental design, next, using response surface methodologies, the reagent consumption was reduced up to 40%, maintaining in all cases high decolourisation percentages (>98%) after 60 min. of phototreatment. In this work, it was also studied the effect of concentration changes of the influent between 100-300 mg/L and the operation of the photocatalytic process near neutral conditions (pH 6.0-6.5) by using ferrioxalate type complex (FeOx).

Improving degradation of paracetamol by integrating gamma radiation and Fenton processes.

PubMed

Cruz-González, Germán; Rivas-Ortiz, Iram B; González-Labrada, Katia; Rapado-Paneque, Manuel; Chávez-Ardanza, Armando; Nuevas-Paz, Lauro; Jáuregui-Haza, Ulises J

2016-10-14

Degradation of paracetamol (N-(4-hydroxiphenyl)acetamide) in aqueous solution by gamma radiation, gamma radiation/H2O2 and gamma radiation/Fenton processes was studied. Parameters affecting the radiolysis of paracetamol such as radiation dose, initial concentration of pollutant, pH and initial oxidant concentration were investigated. Gamma radiation was performed using a (60)Co source irradiator. Paracetamol degradation and mineralization increased with increasing absorbed radiation dose, but decreased with increasing initial concentration of the drug in aqueous solution. The addition of H2O2 resulted in an increased effect on irradiation-driven paracetamol degradation in comparison with the performance of the irradiation-driven process alone: paracetamol removal increased from 48.9% in the absence of H2O2 to 95.2% for H2O2 concentration of 41.7 mmol/L. However, the best results were obtained with gamma radiation/Fenton process with 100% of the drug removal at 5 kGy, for optimal H2O2 and Fe(2+) concentrations at 13.9 and 2.3 mmol/L, respectively, with a high mineralization of 63.7%. These results suggest gamma radiation/H2O2 and gamma radiation/Fenton processes as promising methods for paracetamol degradation in polluted wastewaters.

Decolorization and mineralization of Diarylide Yellow 12 (PY12) by photo-Fenton process: the Response Surface Methodology as the optimization tool.

PubMed

GilPavas, Edison; Dobrosz-Gómez, Izabela; Gómez-García, Miguel Ángel

2012-01-01

The Response Surface Methodology (RSM) was applied as a tool for the optimization of the operational conditions of the photo-degradation of highly concentrated PY12 wastewater, resulting from a textile industry located in the suburbs of Medellin (Colombia). The Box-Behnken experimental Design (BBD) was chosen for the purpose of response optimization. The photo-Fenton process was carried out in a laboratory-scale batch photo-reactor. A multifactorial experimental design was proposed, including the following variables: the initial dyestuff concentration, the H(2)O(2) and the Fe(+2) concentrations, as well as the UV wavelength radiation. The photo-Fenton process performed at the optimized conditions resulted in ca. 100% of dyestuff decolorization, 92% of COD and 82% of TOC degradation. A kinetic study was accomplished, including the identification of some intermediate compounds generated during the oxidation process. The water biodegradability reached a final DBO(5)/DQO = 0.86 value.

Interfacial mechanisms of heterogeneous Fenton reactions catalyzed by iron-based materials: A review.

PubMed

He, Jie; Yang, Xiaofang; Men, Bin; Wang, Dongsheng

2016-01-01

The heterogeneous Fenton reaction can generate highly reactive hydroxyl radicals (OH) from reactions between recyclable solid catalysts and H2O2 at acidic or even circumneutral pH. Hence, it can effectively oxidize refractory organics in water or soils and has become a promising environmentally friendly treatment technology. Due to the complex reaction system, the mechanism behind heterogeneous Fenton reactions remains unresolved but fascinating, and is crucial for understanding Fenton chemistry and the development and application of efficient heterogeneous Fenton technologies. Iron-based materials usually possess high catalytic activity, low cost, negligible toxicity and easy recovery, and are a superior type of heterogeneous Fenton catalysts. Therefore, this article reviews the fundamental but important interfacial mechanisms of heterogeneous Fenton reactions catalyzed by iron-based materials. OH, hydroperoxyl radicals/superoxide anions (HO2/O2(-)) and high-valent iron are the three main types of reactive oxygen species (ROS), with different oxidation reactivity and selectivity. Based on the mechanisms of ROS generation, the interfacial mechanisms of heterogeneous Fenton systems can be classified as the homogeneous Fenton mechanism induced by surface-leached iron, the heterogeneous catalysis mechanism, and the heterogeneous reaction-induced homogeneous mechanism. Different heterogeneous Fenton systems catalyzed by characteristic iron-based materials are comprehensively reviewed. Finally, related future research directions are also suggested. Copyright © 2015. Published by Elsevier B.V.

Physical and oxidative removal of organics during Fenton treatment of mature municipal landfill leachate.

PubMed

Deng, Yang

2007-07-19

Municipal landfill leachate, especially mature leachate, may disrupt the performance of moderately-sized municipal activated sludge wastewater treatment plants, and likewise tend to be recalcitrant to biological pretreatment. Recently, Fenton methods have been investigated for chemical treatment or pre-treatment of mature leachate. In this paper, the results of laboratory tests to determine the roles of oxidation and coagulation in reducing the organic content of mature leachate during Fenton treatment are presented. The efficiencies of chemical oxygen demand (COD) oxidation and coagulation were tested, and the ratio of COD removal by oxidation to that by coagulation was assessed, under various operating conditions. Low initial pH, appropriate relative and absolute Fenton reagent dosages, aeration, and stepwise addition of reagents increased COD removal by oxidation and the importance of oxidation relative to coagulation. Simultaneous aeration and stepwise reagent addition allowed comparable treatment without initial acidification pH, due to the generation of acidic organic intermediates and the continuous input of CO2. On the other hand, high COD oxidation efficiency and low ferrous dosage inhibited COD removal by coagulation. At significantly high oxidation efficiency, overall COD reduction decrease slightly due to low coagulation efficiency. Under the most favorable conditions (initial pH 3, molar ratio [H(2)O(2)]/[Fe2+]=3, [H2O2]=240 mM, and six dosing steps), 61% of the initial COD was removed, and the ratio of COD removal oxidation to coagulation was 0.75. Results highlighted the synergistic roles of oxidation and coagulation in Fenton treatment of mature leachate, and the role of oxidation in controlling the efficiency of removal of COD by coagulation.

Role of sulfate, chloride, and nitrate anions on the degradation of fluoroquinolone antibiotics by photoelectro-Fenton.

PubMed

Villegas-Guzman, Paola; Hofer, Florian; Silva-Agredo, Javier; Torres-Palma, Ricardo A

2017-12-01

Taking ciprofloxacin (CIP) as a fluoroquinolone antibiotic model, this work explores the role of common anions (sulfate, nitrate, and chloride) during the application of photoelectro-Fenton (PEF) at natural pH to degrade this type of compound in water. The system was composed of an IrO 2 anode, Ti, or gas diffusion electrode (GDE) as cathode, Fe 2+ , and UV (254 nm). To determine the implications of these anions, the degradation pathway and efficiency of the PEF sub-processes (UV photolysis, anodic oxidation, and electro-Fenton at natural pH) were studied in the individual presence of the anions. The results highlight that degradation routes and kinetics are strongly dependent on electrolytes. When chloride and nitrate ions were present, indirect electro-chemical oxidation was identified by electro-generated HOCl and nitrogenated oxidative species, respectively. Additionally, direct photolysis and direct oxidation at the anode surface were identified as degradation routes. As a consequence of the different pathways, six primary CIP by-products were identified. Therefore, a scheme was proposed representing the pathways involved in the degradation of CIP when submitted to PEF in water with chloride, nitrate, and sulfate ions, showing the complexity of this process. Promoted by individual and synergistic actions of this process, the PEF system leads to a complete elimination of CIP with total removal of antibiotic activity against Staphylococcus aureus and Escherichia coli, and significant mineralization. Finally, the role of the anions was tested in seawater containing CIP, in which the positive contributions of the anions were partially suppressed by its OH radical scavenger action. The findings are of interest for the understanding of the degradation of antibiotics via the PEF process in different matrices containing sulfate, nitrate, and chloride ions.

Treatment of laundrette wastewater using Starbon and Fenton's reagent.

PubMed

Tony, Maha A; Parker, Helen L; Clark, James H

2016-09-18

The use of grey water for a variety of purposes is gaining increased popularity as a means of preserving scarce freshwater resources. In this work, catalytic oxidation over Fenton's reagent and adsorption techniques using Starbon (mesoporous material derived from polysaccharides) has been applied. These novel techniques are used as an alternative to already studied treatments of grey water such as filtration and/or biological processes. In this study, grey water, collected from a commercial laundrette, has been used. Treatment efficiency was determined by changes in the chemical oxygen demand (COD) of the grey water. Experiments using Fenton's reagent at optimum conditions of Fe(3+) = 40 mg L(-1); H2O2 = 400 mg L(-1) and pH 3 were very successful, resulting in a 95% COD removal after 15 min. Treatment with Starbon adsorption was also effective, reaching up to 81% COD removal at pH 3 within 1 h. The combined treatment with Fenton's reagent and Starbon resulted in a 93% COD removal at a significantly reduced concentration of Fenton's reagent compared to the treatment with solo Fenton's reagent. This lower chemical dose has the advantage of reducing costs and lowering sludge generation.

Involvement of Fenton chemistry in rice straw degradation by the lignocellulolytic bacterium Pantoea ananatis Sd-1.

PubMed

Ma, Jiangshan; Zhang, Keke; Huang, Mei; Hector, Stanton B; Liu, Bin; Tong, Chunyi; Liu, Qian; Zeng, Jiarui; Gao, Yan; Xu, Ting; Liu, Ying; Liu, Xuanming; Zhu, Yonghua

2016-01-01

Lignocellulolytic bacteria have revealed to be a promising source for biofuel production, yet the underlying mechanisms are still worth exploring. Our previous study inferred that the highly efficient lignocellulose degradation by bacterium Pantoea ananatis Sd-1 might involve Fenton chemistry (Fe 2+  + H 2 O 2  + H +  → Fe 3+  + OH· + H 2 O), similar to that of white-rot and brown-rot fungi. The aim of this work is to investigate the existence of this Fenton-based oxidation mechanism in the rice straw degradation process of P. ananatis Sd-1. After 3 days incubation of unpretreated rice straw with P. ananatis Sd-1, the percentage in weight reduction of rice straw as well as its cellulose, hemicellulose, and lignin components reached 46.7, 43.1, 42.9, and 37.9 %, respectively. The addition of different hydroxyl radical scavengers resulted in a significant decline ( P  < 0.001) in rice straw degradation. Pyrolysis gas chromatography-mass spectrometry and Fourier transform infrared spectroscopy analysis revealed the consistency of chemical changes of rice straw components that exists between P. ananatis Sd-1 and Fenton reagent treatment. In addition to the increased total iron ion concentration throughout the rice straw decomposition process, the Fe 3+ -reducing capacity of P. ananatis Sd-1 was induced by rice straw and predominantly contributed by aromatic compounds metabolites. The transcript levels of the glucose-methanol-choline oxidoreductase gene related to hydrogen peroxide production were significantly up-regulated (at least P  < 0.01) in rice straw cultures. Higher activities of GMC oxidoreductase and less hydrogen peroxide concentration in rice straw cultures relative to glucose cultures may be responsible for increasing rice straw degradation, which includes Fenton-like reactions. Our results confirmed the Fenton chemistry-assisted degradation model in P. ananatis Sd-1. We are among the first to show that a Fenton-based oxidation mechanism exists in a bacteria degradation system, which provides a new perspective for how natural plant biomass is decomposed by bacteria. This degradative system may offer an alternative approach to the fungi system for lignocellulosic biofuels production.

Municipal Leachate Treatment by Fenton Process: Effect of Some Variable and Kinetics

PubMed Central

Ahmadian, Mohammad; Reshadat, Sohyla; Yousefi, Nader; Mirhossieni, Seyed Hamed; Zare, Mohammad Reza; Ghasemi, Seyed Ramin; Rajabi Gilan, Nader; Khamutian, Razieh; Fatehizadeh, Ali

2013-01-01

Due to complex composition of leachate, the comprehensive leachate treatment methods have been not demonstrated. Moreover, the improper management of leachate can lead to many environmental problems. The aim of this study was application of Fenton process for decreasing the major pollutants of landfill leachate on Kermanshah city. The leachate was collected from Kermanshah landfill site and treated by Fenton process. The effect of various parameters including solution pH, Fe2+ and H2O2 dosage, Fe2+/H2O2 molar ratio, and reaction time was investigated. The result showed that with increasing Fe2+ and H2O2 dosage, Fe2+/H2O2 molar ratio, and reaction time, the COD, TOC, TSS, and color removal increased. The maximum COD, TOC, TSS, and color removal were obtained at low pH (pH: 3). The kinetic data were analyzed in term of zero-order, first-order, and second-order expressions. First-order kinetic model described the removal of COD, TOC, TSS, and color from leachate better than two other kinetic models. In spite of extremely difficulty of leachate treatment, the previous results seem rather encouraging on the application of Fenton's oxidation. PMID:23840229

Elimination of pyraclostrobin by simultaneous microbial degradation coupled with the Fenton process in microbial fuel cells and the microbial community.

PubMed

Zhao, Huanhuan; Kong, Chui-Hua

2018-06-01

The elimination of pyraclostrobin by simultaneous microbial degradation and Fenton oxidation was achieved in a microbial fuel cell (MFC) system. After 12 h of incubation, the removal rate of pyraclostrobin was 1.4 mg/L/h at the anode and 1.7 mg/L/h at the cathode. The pyraclostrobin concentration was less than the detection limit (0.1 mg/L) after 72 h at the anode and 24 h at the cathode. The air flow rate, temperature, and pH of the catholyte had significant effects on the generation of H 2 O 2 . The maximum production of H 2 O 2 was 1.2 mg/L after reaction for 20 h during the Fenton process. Microbial community analysis indicated that functional bacteria in the genera Chryseobacterium, Stenotrophomonas, Arcobacter, and Comamonas were predominant in the anodic biofilm. In conclusion, the MFC-Fenton system provides an effective approach for treating environmental contaminants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of temperature on adsorption and oxidative degradation of bisphenol A in an acid-treated iron-amended granular activated carbon

EPA Science Inventory

The present study suggests a combined adsorption and Fenton oxidation using an acid treated Fe-amended granular activated carbon (Fe-GAC) for effective removal of bisphenol A in water. When the Fe-GAC adsorbs and is saturated with BPA in water, Fenton oxidation of BPA occurs in ...

Mineralization of the textile dye acid yellow 42 by solar photoelectro-Fenton in a lab-pilot plant.

PubMed

Espinoza, Carolina; Romero, Julio; Villegas, Loreto; Cornejo-Ponce, Lorena; Salazar, Ricardo

2016-12-05

A complete mineralization of a textile dye widely used in the Chilean textile industry, acid yellow 42 (AY42), was studied. Degradation was carried out in an aqueous solution containing 100mgL(-1) of total organic carbon (TOC) of dye using the advanced solar photoelectro-Fenton (SPEF) process in a lab-scale pilot plant consisting of a filter press cell, which contains a boron doped diamond electrode and an air diffusion cathode (BDD/air-diffusion cell), coupled with a solar photoreactor for treat 8L of wastewater during 270min of electrolysis. The main results obtained during the degradation of the textile dye were that a complete transformation to CO2 depends directly on the applied current density, the concentration of Fe(2+) used as catalyst, and the solar radiation intensity. The elimination of AY42 and its organic intermediates was due to hydroxyl radicals formed at the anode surface from water oxidation and in the bulk from Fenton's reaction between electrogenerated H2O2 and added Fe(2+). The application of solar radiation in the process (SPEF) yield higher current efficiencies and lower energy consumptions than electro-Fenton (EF) and electro-oxidation with electrogenerated H2O2 (E OH2O2) by the additional production of hydroxyl radicals from the photolysis of Fe(III) hydrated species and the photodecomposition of Fe(III) complexes with organic intermediates. Moreover, some products and intermediates formed during mineralization of dye, such as inorganic ions, carboxylic acids and aromatic compounds were determined by photometric and chromatographic methods. An oxidation pathway is proposed for the complete conversion to CO2. Copyright © 2016 Elsevier B.V. All rights reserved.

Oxygen Reduction Reaction on Graphene in an Electro-Fenton System: In Situ Generation of H2 O2 for the Oxidation of Organic Compounds.

PubMed

Chen, Chen-Yu; Tang, Cheng; Wang, Hao-Fan; Chen, Cheng-Meng; Zhang, Xiaoyuan; Huang, Xia; Zhang, Qiang

2016-05-23

Fenton oxidation using an aqueous mixture of Fe(2+) and H2 O2 is a promising environmental remediation strategy. However, the difficulty of storage and shipment of concentrated H2 O2 and the generation of iron sludge limit its broad application. Therefore, highly efficient and cost-effective electrocatalysts are in great need. Herein, a graphene catalyst is proposed for the electro-Fenton process, in which H2 O2 is generated in situ by the two-electron reduction of the dissolved O2 on the cathode and then decomposes to generate (.) OH in acidic solution with Fe(2+) . The π bond of the oxygen is broken whereas the σ bond is generally preserved on the metal-free reduced graphene oxide owing to the high free energy change. Consequently, the oxygen is reduced to H2 O2 through a two-electron pathway. The thermally reduced graphene with a high specific surface area (308.8 m(2)  g(-1) ) and a large oxygen content (10.3 at %) exhibits excellent reactivity for the two-electron oxygen reduction reaction to H2 O2 . A highly efficient peroxide yield (64.2 %) and a remarkable decolorization of methylene blue (12 mg L(-1) ) of over 97 % in 160 min are obtained. The degradation of methylene blue with hydroxyl radicals generated in situ is described by a pseudo first-order kinetics model. This provides a proof-of-concept of an environmentally friendly electro-Fenton process using graphene for the oxygen reduction reaction in an acidic solution to generate H2 O2 . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combined treatment technology based on synergism between hydrodynamic cavitation and advanced oxidation processes.

PubMed

Gogate, Parag R; Patil, Pankaj N

2015-07-01

The present work highlights the novel approach of combination of hydrodynamic cavitation and advanced oxidation processes for wastewater treatment. The initial part of the work concentrates on the critical analysis of the literature related to the combined approaches based on hydrodynamic cavitation followed by a case study of triazophos degradation using different approaches. The analysis of different combinations based on hydrodynamic cavitation with the Fenton chemistry, advanced Fenton chemistry, ozonation, photocatalytic oxidation, and use of hydrogen peroxide has been highlighted with recommendations for important design parameters. Subsequently degradation of triazophos pesticide in aqueous solution (20 ppm solution of commercially available triazophos pesticide) has been investigated using hydrodynamic cavitation and ozonation operated individually and in combination for the first time. Effect of different operating parameters like inlet pressure (1-8 bar) and initial pH (2.5-8) have been investigated initially. The effect of addition of Fenton's reagent at different loadings on the extent of degradation has also been investigated. The combined method of hydrodynamic cavitation and ozone has been studied using two approaches of injecting ozone in the solution tank and at the orifice (at the flow rate of 0.576 g/h and 1.95 g/h). About 50% degradation of triazophos was achieved by hydrodynamic cavitation alone under optimized operating parameters. About 80% degradation of triazophos was achieved by combination of hydrodynamic cavitation and Fenton's reagent whereas complete degradation was achieved using combination of hydrodynamic cavitation and ozonation. TOC removal of 96% was also obtained for the combination of ozone and hydrodynamic cavitation making it the best treatment strategy for removal of triazophos. Copyright © 2014 Elsevier B.V. All rights reserved.

Remediation of water pollution caused by pharmaceutical residues based on electrochemical separation and degradation technologies: a review.

PubMed

Sirés, Ignasi; Brillas, Enric

2012-04-01

In the last years, the decontamination and disinfection of waters by means of direct or integrated electrochemical processes are being considered as a very appealing alternative due to the significant improvement of the electrode materials and the coupling with low-cost renewable energy sources. Many electrochemical technologies are currently available for the remediation of waters contaminated by refractory organic pollutants such as pharmaceutical micropollutants, whose presence in the environment has become a matter of major concern. Recent reviews have focused on the removal of pharmaceutical residues upon the application of other important methods like ozonation and advanced oxidation processes. Here, we present an overview on the electrochemical methods devised for the treatment of pharmaceutical residues from both, synthetic solutions and real pharmaceutical wastewaters. Electrochemical separation technologies such as membrane technologies, electrocoagulation and internal micro-electrolysis, which only isolate the pollutants from water, are firstly introduced. The fundamentals and experimental set-ups involved in technologies that allow the degradation of pharmaceuticals, like anodic oxidation, electro-oxidation with active chlorine, electro-Fenton, photoelectro-Fenton and photoelectrocatalysis among others, are further discussed. Progress on the promising solar photoelectro-Fenton process devised and further developed in our laboratory is especially highlighted and documented. The abatement of total organic carbon or reduction of chemical oxygen demand from contaminated waters allows the comparison between the different methods and materials. The routes for the degradation of the some pharmaceuticals are also presented. Copyright © 2011 Elsevier Ltd. All rights reserved.

The decolorization and mineralization of acid orange 6 azo dye in aqueous solution by advanced oxidation processes: a comparative study.

PubMed

Hsing, Hao-Jan; Chiang, Pen-Chi; Chang, E-E; Chen, Mei-Yin

2007-03-06

The comparison of different advanced oxidation processes (AOPs), i.e. ultraviolet (UV)/TiO(2), O(3), O(3)/UV, O(3)/UV/TiO(2), Fenton and electrocoagulation (EC), is of interest to determine the best removal performance for the destruction of the target compound in an Acid Orange 6 (AO6) solution, exploring the most efficient experimental conditions as well; on the other hand, the results may provide baseline information of the combination of different AOPs in treating industrial wastewater. The following conclusions can be drawn: (1) in the effects of individual and combined ozonation and photocatalytic UV irradiation, both O(3)/UV and O(3)/UV/TiO(2) processes exhibit remarkable TOC removal capability that can achieve a 65% removal efficiency at pH 7 and O(3) dose=45mg/L; (2) the optimum pH and ratio of [H(2)O(2)]/[Fe(2+)] found for the Fenton process, are pH 4 and [H(2)O(2)]/[Fe(2+)]=6.58. The optimum [H(2)O(2)] and [Fe(2+)] under the same HF value are 58.82 and 8.93mM, respectively; (3) the optimum applied voltage found in the EC experiment is 80V, and the initial pH will affect the AO6 and TOC removal rates in that acidic conditions may be favorable for a higher removal rate; (4) the AO6 decolorization rate ranking was obtained in the order of O(3)

Comparative study of the effect of pharmaceutical additives on the elimination of antibiotic activity during the treatment of oxacillin in water by the photo-Fenton, TiO2-photocatalysis and electrochemical processes.

PubMed

Serna-Galvis, Efraim A; Silva-Agredo, Javier; Giraldo, Ana L; Flórez-Acosta, Oscar A; Torres-Palma, Ricardo A

2016-01-15

Synthetic pharmaceutical effluents loaded with the β-lactam antibiotic oxacillin were treated using advanced oxidation processes (the photo-Fenton system and TiO2 photocatalysis) and chloride mediated electrochemical oxidation (with Ti/IrO2 anodes). Combinations of the antibiotic with excipients (mannitol or tartaric acid), an active ingredient (calcium carbonate, i.e. bicarbonate ions due to the pH) and a cleaning agent (sodium lauryl ether sulfate) were considered. Additionally, urban wastewater that had undergone biological treatment was doped with oxacillin and treated with the tested systems. The evolution of antimicrobial activity was monitored as a parameter of processes efficiency. Although the two advanced oxidation processes (AOPs) differ only in the way they produce OH, marked differences were observed between them. There were also differences between the AOPs and the electrochemical system. Interestingly, each additive had a different effect on each treatment. For water loaded with mannitol, electrochemical treatment was the most suitable option because the additive did not significantly affect the efficiency of the system. Due to the formation of a complex with Fe(3+), tartaric acid accelerated the elimination of antibiotic activity during the photo-Fenton process. For TiO2 photocatalysis, the presence of bicarbonate ions contributed to antibiotic activity elimination through the possible formation of carbonate and bicarbonate radicals. Sodium lauryl ether sulfate negatively affected all of the processes. However, due to the higher selectivity of HOCl compared with OH, electrochemical oxidation showed the least inhibited efficiency. For the urban wastewater doped with oxacillin, TiO2 photocatalysis was the most efficient process. These results will help select the most suitable technology for the treatment of water polluted with β-lactam antibiotics. Copyright © 2015 Elsevier B.V. All rights reserved.

Trimethoprim degradation by Fenton and Fe(II)-activated persulfate processes.

PubMed

Wang, Shizong; Wang, Jianlong

2018-01-01

Trimethoprim is a pollutant ubiquitous in the environment due to its extensive application, and it cannot be effectively removed by conventional wastewater treatment processes. In this study, the Fenton and the Fe(II)-activated persulfate processes were employed to degrade trimethoprim in an aqueous solution. The results showed that the concentration of persulfate, H 2 O 2 and Fe(II) a had significant influence on the degradation of trimethoprim in both processes. De-ionized water spiked with trimethoprim resulted in the complete degradation of trimethoprim (0.05 mM) by the mineralization of 54.9% of Fenton's reagent when the concentrations of H 2 O 2 and Fe(II) were 1 mM and 0.05 mM, respectively. In contrast, 73.4% of trimethoprim was degraded by the mineralization of 40.5% of the Fe(II)-activated persulfate process when the concentration of persulfate and Fe(II) were each 4 mM. Intermediate compounds with different m/z were detected for the Fenton and the Fe(II)-activated persulfate processes, indicating alternative degradation pathways. In the actual wastewater spiked with trimethoprim, the removal efficiency of trimethoprim decreased to 35.8% and 43.6%, respectively, for the Fenton and the Fe(II)-activated persulfate processes. In addition, the decomposition efficiencies for hydrogen peroxide and persulfate were 43.8% and 92.5%, respectively, which was lower than those in the de-ionized water system. These results demonstrated that wastewater components had a negative influence on trimethoprim degradation and the decomposition of the oxidants (persulfate and H 2 O 2 ). In summary, the Fe(II)-activated persulfate process could be used as an alternative technology for treating trimethoprim-containing wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Effect of Citric Acid on the Oxidation of Organic Contaminants by Fenton's Reagent

NASA Astrophysics Data System (ADS)

Seol, Y.; Javandel, I.; Lee, G.

2003-12-01

Combined with acids and iron catalysts, hydrogen peroxide (H2O2) as Fenton's reagent is proven to be effective in oxidizing halogenated volatile organic compounds (VOCs). The Fenton's reagent, traditionally used for waste water treatment technique, has been applied to the remediation of contaminated soil systems and numerous investigators have found intrinsic iron salts are effective source of iron catalyst for the reaction. Citric acid, which is naturally occurring nutrients to microorganisms and less destructive to soil chemical properties, is selected for an acidifying agent to create acidic soil condition. However, citric acid has been considered as a reaction inhibitant because it sequesters ferric iron from Fenton's catalytic cycle by forming strong chelates with iron. This paper presents the feasibility of using citric acid as an acidifying agent of soil matrix for the Fenton-like oxidation. Series of batch tests were performed to test disappearance of VOCs in various aqueous systems with two acidifying agents (citric acid or sulfuric acid) and three iron sources (iron sulfate, water soluble soil iron, or soil matrix). Batch results show that soluble iron is essential for near complete disappearance of VOCs and that citric acid performs similarly to sulfuric acid at low H2O2 dosage (< 1 wt%). The test soil provided water-soluble soil iron but also contained scavengers of the oxidizing agents, resulting in limited removals of VOCs. Column tests confirmed the results of the batch tests, suggesting citric acid is also as effective as sulfuric acid in providing acidic environment for the Fenton-like oxidation. The batch experiments also reveal that higher doses of H2O2 lower the degree of VOC removals in citric acid systems. Potential explanations for this declining include that excessive presence of H2O2 expedites the oxidation of ferrous to ferric iron, which then forms a strong complex with citrate, leading to the sequestration of the iron from the Fenton's reaction cycle. Consequently, additional supply of ferrous iron would be required for continuing oxidation of VOCs, as well as slow injection of H2O2. Detailed mechanistic study would be needed for factual understanding.

Decomplexation efficiency and mechanism of Cu(II)-EDTA by H2O2 coupled internal micro-electrolysis process.

PubMed

Zhou, Dongfang; Hu, Yongyou; Guo, Qian; Yuan, Weiguang; Deng, Jiefan; Dang, Yapan

2016-12-29

Internal micro-electrolysis (IE) coupled with Fenton oxidation (IEF) was a very effective technology for copper (Cu)-ethylenediaminetetraacetic acid (EDTA) wastewater treatment. However, the mechanisms of Cu 2+ removal and EDTA degradation were scarce and lack persuasion in the IEF process. In this paper, the decomplexation and removal efficiency of Cu-EDTA and the corresponding mechanisms during the IEF process were investigated by batch test. An empirical equation and the oxidation reduction potential (ORP) index were proposed to flexibly control IE and the Fenton process, respectively. The results showed that Cu 2+ , total organic carbon (TOC), and EDTA removal efficiencies were 99.6, 80.3, and 83.4%, respectively, under the proper operation conditions of iron dosage of 30 g/L, Fe/C of 3/1, initial pH of 3.0, Fe 2+ /H 2 O 2 molar ratio of 1/4, and reaction time of 20 min, respectively for IE and the Fenton process. The contributions of IE and Fenton to Cu 2+ removal were 91.2 and 8.4%, respectively, and those to TOC and EDTA removal were 23.3, 25.1, and 57, 58.3%, respectively. It was found that Fe 2+ -based replacement-precipitation and hydroxyl radical (•OH) were the most important effects during the IEF process. •OH played an important role in the degradation of EDTA, whose yield and productive rate were 3.13 mg/L and 0.157 mg/(L min -1 ), respectively. Based on the intermediates detected by GC-MS, including acetic acid, propionic acid, pentanoic acid, amino acetic acid, 3-(diethylamino)-1,2-propanediol, and nitrilotriacetic acid (NTA), a possible degradation pathway of Cu-EDTA in the IEF process was proposed. Graphical abstract The mechanism diagram of IEF process.

Enhancement of Fenton processes at initial circumneutral pH for the degradation of norfloxacin with Fe@Fe2O3 core-shell nanomaterials.

PubMed

Liu, Jingyi; Hu, Wenyong; Sun, Maogui; Xiong, Ouyang; Yu, Haibin; Feng, Haopeng; Wu, Xuan; Tang, Lin; Zhou, Yaoyu

2018-06-13

The degradation of norfloxacin by Fenton reagent with core-shell Fe@Fe 2 O 3 nanomaterials was studied under neutral conditions in a closed batch system. Norfloxacin was significantly degraded (90%) in the Fenton system with Fe@Fe 2 O 3 in 30 min at the initial pH 7.0, but slightly degraded in Fenton system without Fe@Fe 2 O 3 under the same experimental conditions. The intermediate products were investigated by gas chromatography-mass spectrometry, and the possible Fenton oxidation pathway of norfloxacin in the presence of Fe@Fe 2 O 3 nanowires was proposed. Electron spin resonance spectroscopy was used to identify and characterize the free radicals generated, and the mechanism for norfloxacin degradation was also revealed. Finally, the reusability and the stability of Fe@Fe 2 O 3 nanomaterials were studied using x-ray diffraction and scanning electron microscope, which indicated that Fe@Fe 2 O 3 is a stable catalyst and can be used repetitively in environmental pollution control.

Electro-Fenton for control and removal of micropollutants - process optimization and energy efficiency.

PubMed

Mousset, E; Wang, Z; Lefebvre, O

2016-11-01

The removal of micropollutants is an important environmental and health issue. Electro-Fenton offers an electrochemical advanced treatment that is particularly effective for the breakdown of aromatic contaminants. Due to the wide variety of chemicals, it is preferable to analyze model contaminants, such as phenol, when optimizing and assessing the efficacy of a novel treatment process. In this study, we therefore made use of innovative types of electrode material and optimized operating parameters (current density and aeration rate) for the removal of phenol by electro-Fenton, with a view to maximize the energy efficiency of the process. By determining the best current density (1.25 mA cm -2 ), frequency of aeration (continuous) and by using a boron-doped diamond (BDD) anode, it was possible to achieve over 98.5% phenol (1 mM) removal within 1.5 h. BDD further outcompeted platinum as anode material in terms of mineralization rate and yield, and displayed low energy consumption of 0.08 kWh (g-TOC) -1 , about one order of magnitude lower than other advanced oxidation processes, such as UV/TiO 2 and UV/O 3 . Furthermore, a carbon cloth anode proved even more cost-effective than BDD if the end goal is the removal of phenol by electro-Fenton instead of complete mineralization.

INFLUENCE OF PEAT ON FENTON OXIDATION

EPA Science Inventory

A diagnostic probe was used to estimate the activity of Fenton-derived hydroxyl radicals (@OH), reaction kinetics, and oxidation efficiency in batch suspensions comprised of silica sand, crushed goethite ("-FeOOH) ore, peat, and H2O2 (0.13 mM). A simple method of kinetic analysi...

Improved removal performance and mechanism investigation of papermaking wastewater treatment using manganese enhanced Fenton reaction.

PubMed

Wang, Yingcai; Wang, Can; Shi, Shuai; Fang, Shuai

2018-06-01

The effects of Mn(II) on Fenton system to treat papermaking wastewater and the mechanism of Mn(II) enhanced Fenton reaction were investigated in this study. The chemical oxygen demand (COD) removal efficiency was enhanced in the presence of Mn(II), which increased by 19% compared with that of the Fenton system alone. The pseudo-first order reaction kinetic rate constant of Mn(II)/Fenton system was 2.11 times higher than that of Fenton system. 67%-81% COD were removed with the increasing Mn(II) concentration from 0 to 0.8 g/L. COD removal efficiency was also enhanced in a wider pH range (3-7), which indicated the operation parameters of Fenton technology could be broadened to a milder condition. The study of the mechanism showed that Mn(II) participated in the oxidation and coagulation stages in Fenton system. In the oxidation stage, Mn(II) promotes the production of HO 2 •/ O 2 • - , then HO 2 •/ O 2 • - reacts with Fe(III) to accelerate the formation of Fe(II), and finally accelerates the production of HO•. Meantime MnMnO 3 and Fe(OH) 3 forms in the coagulation stage, facilitating the removal of suspended substances and a large amount of COD, which enhances the overall COD removal of papermaking wastewater. This study provided a detailed mechanism to improve practical applications of Fenton technology.

Homogenous and heterogenous advanced oxidation of two commercial reactive dyes.

PubMed

Balcioglu, I A; Arslan, I; Sacan, M T

2001-07-01

Two commercial reactive dyes, the azo dye Reactive Black 5 and the copper phythalocyanine dye Reactive Blue 21, have been treated at a concentration of 75 mg l(-1) by titanium dioxide mediated photocatalytic (TiO2/UV), dark and UV-light assisted Fenton (Fe2+/H2O2) and Fenton-like (Fe3+/H2O2) processes in acidic medium. For the treatment of Reactive Black 5, all investigated advanced oxidation processes were quite effective in terms of colour, COD as well as TOC removal. Moreover, the relative growth inhibition of the azo dye towards the marine algae Dunaliella tertiolecta that was initially 70%, did not exhibit an increase during the studied advanced oxidation reactions and complete detoxification at the end of the treatment period could be achieved for all investigated treatment processes. However, for Reactive Blue 21, abatement in COD and UV-VIS absorbance values was mainly due to the adsorption of the dye on the photocatalyst surface and/or the coagulative effect of Fe3+/Fe2+ ions. Although only a limited fraction of the copper phythalocyanine dye underwent oxidative degradation, 47% of the total copper in the dye was already released after 1 h photocatalytic treatment.

Arsenic remediation from drinking water using Fenton's reagent with slow sand filter.

PubMed

Jasudkar, Dipali; Rakhunde, Rupali; Deshpande, Leena; Labhasetwar, Pawan; Juneja, H D

2012-12-01

This paper describes the development of a remediation approach based on the pre-oxidation using Fenton's reagent and the subsequent removal of arsenic (As) through sand filtration from drinking water. The efficiency of the process was carried out including As(III) and As(V) with various concentration ratios up to 3,000 ppb. Efficient removal of As was observed within WHO guideline value of 10 ppb. The recoveries of samples were found to be 98 % ± 2.5 %. The process was applied to field samples, where results show considerable reduction in As concentrations. This process is cost effective for treatment of drinking water with high concentration of As.

Combined ultrasound and Fenton (US-Fenton) process for the treatment of ammunition wastewater.

PubMed

Li, Yangang; Hsieh, Wen-Pin; Mahmudov, Rovshan; Wei, Xiaomei; Huang, C P

2013-01-15

A wastewater collected from a regional ammunition process site was treated with combined US-Fenton process. Factors such as pH, temperature, reaction time, US energy intensity, initial TOC concentration, and the molar ratio of iron to hydrogen peroxide that might affect the treatment efficiency were investigated. The removal of TOC, COD, and color increased with decreasing pH and increasing temperature and US intensity. Color was removed rapidly reaching 85% in 10 min; whereas TOC and COD were removed slowly, only about 20% for both in 10 min and approaching 65 and 92% removal in 120 min, respectively. The optimal molar ratio of Fe(II) to H(2)O(2) for TOC and COD removal was 500. The results showed that the change in the average carbon oxidation number (ACON) was parallel to that of the removal efficiency of TOC, COD, and color. The toxicity of treated wastewater was reduced as assessed by the respiration rate of Escherichia coli. Copyright © 2013 Elsevier B.V. All rights reserved.

Application of UV-irradiated Fe(III)-nitrilotriacetic acid (UV-Fe(III)NTA) and UV-NTA-Fenton systems to degrade model and natural occurring naphthenic acids.

PubMed

Zhang, Ying; Chelme-Ayala, Pamela; Klamerth, Nikolaus; Gamal El-Din, Mohamed

2017-07-01

Naphthenic acids (NAs) are a highly complex mixture of organic compounds naturally present in bitumen and identified as the primary toxic constituent of oil sands process-affected water (OSPW). This work investigated the degradation of cyclohexanoic acid (CHA), a model NA compound, and natural occurring NAs during the UV photolysis of Fe(III)-nitrilotriacetic acid (UV-Fe(III)NTA) and UV-NTA-Fenton processes. The results indicated that in the UV-Fe(III)NTA process at pH 8, the CHA removal increased with increasing NTA dose (0.18, 0.36 and 0.72 mM), while it was independent of the Fe(III) dose (0.09, 0.18 and 0.36 mM). Moreover, the three Fe concentrations had no influence on the photolysis of the Fe(III)NTA complex. The main responsible species for the CHA degradation was hydroxyl radical (OH), and the role of dissolved O 2 in the OH generation was found to be negligible. Real OSPW was treated with the UV-Fe(III)NTA and UV-NTA-Fenton advanced oxidation processes (AOPs). The removals of classical NAs (O 2 -NAs), oxidized NAs with one additional oxygen atom (O 3 -NAs) and with two additional oxygen atoms (O 4 -NAs) were 44.5%, 21.3%, and 25.2% in the UV-Fe(III)NTA process, respectively, and 98.4%, 86.0%, and 81.0% in the UV-NTA-Fenton process, respectively. There was no influence of O 2 on the NA removal in these two processes. The results also confirmed the high reactivity of the O 2 -NA species with more carbons and increasing number of rings or double bond equivalents. This work opens a new window for the possible treatment of OSPW at natural pH using these AOPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Particle Size Effects on Fenton Regeneration of MTBE-spent Activated Carbon

EPA Science Inventory

Fenton-driven regeneration of spent granular activated carbon (GAC) is a developing technology that may reduce water treatment costs. In this study, the effect of GAC particle size on Fenton-driven oxidation of methyl tert-butyl ether (MTBE)-spent GAC was evaluated. The GAC was...

Iron Amendment and Fenton Oxidation of MTBE-Spent Granular Activated Carbon

EPA Science Inventory

Fenton-driven regeneration of Methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) involves Fe amendment to the GAC to catalyze H2O2 reactions and to enhance the rate of MTBE oxidation and GAC regeneration. Four forms of iron (ferric sulfate, ferric chloride, fer...

Enhancement of a solar photo-Fenton reaction with ferric-organic ligands for the treatment of acrylic-textile dyeing wastewater.

PubMed

Soares, Petrick A; Batalha, Mauro; Souza, Selene M A Guelli U; Boaventura, Rui A R; Vilar, Vítor J P

2015-04-01

Literature describes a kinetic mineralization profile for most of acrylic-textile dyeing wastewaters using a photo-Fenton reaction characterized by a slow degradation process and high reactants consumption. This work tries to elucidate that the slow decay on DOC concentration is associated with the formation of stable complexes between Fe(3+) and textile auxiliary products, limiting the photoreduction of Fe(3+). This work also evaluates the enhancement of a solar photo-Fenton reaction through the use of different ferric-organic ligands applied to the treatment of a simulated acrylic-textile dyeing wastewater, as a pre-oxidation step to enhance its biodegradability. The photo-Fenton reaction was negatively affected by two dyeing auxiliary products: i) Sera(®) Tard A-AS, a surfactant mainly composed of alkyl dimethyl benzyl ammonium chloride and ii) Sera(®) Sperse M-IW, a dispersing agent composed of polyglycol solvents. The catalytic activity of the organic ligands toward the ferrous-catalysed system followed this order: Fe(III)-Oxalate > Fe(III)-Citrate > Fe(III)-EDDS, and all were better than the traditional photo-Fenton reaction. Different design parameters such as iron concentration, pH, temperature, flow conditions, UV irradiance and H2O2 addition strategy and dose were evaluated. The ferrioxalate induced photo-Fenton process presented the best results, achieving 87% mineralization after 9.3 kJUV L(-1) and allowing to work until near neutral pH values. As expected, the biodegradability of the textile wastewater was significantly enhanced during the photo-Fenton treatment, achieving a value of 73%, consuming 32.4 mM of H2O2 and 5.7 kJUV L(-1). Copyright © 2015 Elsevier Ltd. All rights reserved.

Photo-oxidation of PAHs with calcium peroxide as a source of the hydroxyl radicals

NASA Astrophysics Data System (ADS)

Kozak, Jolanta; Włodarczyk-Makuła, Maria

2018-02-01

The efficiency of the removal of selected PAHs from the pretreated coking wastewater with usage of CaO2, Fenton reagent (FeSO4) and UV rays are presented in this article. The investigations were carried out using coking wastewater originating from biological, industrial wastewater treatment plant. At the beginning of the experiment, the calcium peroxide (CaO2) powder as a source of hydroxyl radicals (OH•) and Fenton reagent were added to the samples of wastewater. Then, the samples were exposed to UV rays for 360 s. The process was carried out at pH 3.5-3.8. After photo-oxidation process a decrease in the PAHs concentration was observed. The removal efficiency of selected hydrocarbons was in the ranged of 89-98%. The effectiveness of PAHs degradation was directly proportional to the calcium peroxide dose.

Textile wastewater reuse after additional treatment by Fenton's reagent.

PubMed

Ribeiro, Marília Cleto Meirelles; Starling, Maria Clara V M; Leão, Mônica Maria Diniz; de Amorim, Camila Costa

2017-03-01

This study verifies textile wastewater reuse treated by the conventional activated sludge process and subjected to further treatment by advanced oxidation processes. Three alternative processes are discussed: Fenton, photo-Fenton, and UV/H 2 O 2 . Evaluation of treatments effects was based on factorial experiment design in which the response variables were the maximum removal of COD and the minimum concentration of residual H 2 O 2 in treated wastewater. Results indicated Fenton's reagent, COD/[H 2 O 2 ]/[Fe 2+ ] mass ratio of 1:2:2, as the best alternative. The selected technique was applied to real wastewater collected from a conventional treatment plant of a textile mill. The quality of the wastewater before and after the additional treatment was monitored in terms of 16 physicochemical parameters defined as suitable for the characterization of waters subjected to industrial textile use. The degradation of the wastewater was also evaluated by determining the distribution of its molecular weight along with the organic matter fractionation by ultrafiltration, measured in terms of COD. Finally, a sample of the wastewater after additional treatment was tested for reuse at pilot scale in order to evaluate the impact on the quality of dyed fabrics. Results show partial compliance of treated wastewater with the physicochemical quality guidelines for reuse. Removal and conversion of high and medium molecular weight substances into low molecular weight substances was observed, as well as the degradation of most of the organic matter originally present in the wastewater. Reuse tests indicated positive results, confirming the applicability of wastewater reuse after the suggested additional treatment. Graphical abstract Textile wastewater samples after additional treatment by Fenton's reagent, photo-Fenton and H 2 O 2 /UV tested in different conditions.

Application of electrochemical advanced oxidation to bisphenol A degradation in water. Effect of sulfate and chloride ions.

PubMed

Burgos-Castillo, Rutely C; Sirés, Ignasi; Sillanpää, Mika; Brillas, Enric

2018-03-01

Electrochemical oxidation with electrogenerated H 2 O 2 (EO- H 2 O 2 ), electro-Fenton (EF), photoelectro-Fenton (PEF) and solar PEF (SPEF) have been applied to mineralize bisphenol A solutions in 0.050 M Na 2 SO 4 or 0.008 M NaCl + 0.047 M Na 2 SO 4 at pH 3.0. The assays were performed in an undivided cell with a boron-doped diamond (BDD) anode and an air-diffusion cathode for continuous H 2 O 2 production. The PEF and SPEF processes yielded almost total mineralization due to the potent synergistic action of generated hydroxyl radicals and active chlorine, in conjunction with the photolytic action of UV radiation. The higher intensity of UV rays from sunlight explained the superior oxidation ability of SPEF. The effect of applied current density was studied in all treatments, whereas the role of bisphenol A concentration was examined in PEF. Bisphenol A abatement followed a pseudo-first-order kinetics, which was very quick in SPEF since UV light favored a large production of hydroxyl radicals from Fenton's reaction. Eight non-chlorinated and six chlorinated aromatics were identified as primary products in the chloride matrix. Ketomalonic, tartronic, maleic and oxalic acids were detected as final short-chain aliphatic carboxylic acids. The large stability of Fe(III)-oxalate complexes in EF compared to their fast photomineralization in PEF and PEF accounted for by the superior oxidation power of the latter processes. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Fosetyl-Al photo-Fenton degradation and its endogenous catalyst inhibition.

PubMed

Micó, María M; Zapata, Ana; Maldonado, Manuel I; Bacardit, Jordi; Malfeito, Jorge; Sans, Carme

2014-01-30

Interferences from many sources can affect photo-Fenton reaction performance. Among them, catalyst inhibition can be caused by the complexation and/or precipitation of iron species by the organic matter and salts present in the reaction media. This is the case of the oxidation of effluents containing organophosphorous fosetyl-Al. The degradation of this fungicide generates phosphate anions that scavenge iron and hinder Fe(II) availability. Experimental design was applied to artificially enlighten photo-Fenton reaction, in order to evaluate fosetyl-Al degradation. The performed experiments suggested how iron inhibition takes place. The monitoring of photo-Fenton reaction over a mixture of fosetyl-Al with other two pesticides also showed the interferences caused by the presence of the fungicide on other species degradation. Solar empowered photo-Fenton was also essayed for comparison purposes. Artificial and solar light photo-Fenton reactions were revealed as effective treatments for the elimination of tested fungicide. However, the phosphate ions generated during fosetyl oxidation decreased iron availability, what hampered organic matter degradation. Copyright © 2014 Elsevier B.V. All rights reserved.

Optimization of the synthesis process of an iron oxide nanocatalyst supported on activated carbon for the inactivation of Ascaris eggs in water using the heterogeneous Fenton-like reaction.

PubMed

Morales-Pérez, Ariadna A; Maravilla, Pablo; Solís-López, Myriam; Schouwenaars, Rafael; Durán-Moreno, Alfonso; Ramírez-Zamora, Rosa-María

2016-01-01

An experimental design methodology was used to optimize the synthesis of an iron-supported nanocatalyst as well as the inactivation process of Ascaris eggs (Ae) using this material. A factor screening design was used for identifying the significant experimental factors for nanocatalyst support (supported %Fe, (w/w), temperature and time of calcination) and for the inactivation process called the heterogeneous Fenton-like reaction (H2O2 dose, mass ratio Fe/H2O2, pH and reaction time). The optimization of the significant factors was carried out using a face-centered central composite design. The optimal operating conditions for both processes were estimated with a statistical model and implemented experimentally with five replicates. The predicted value of the Ae inactivation rate was close to the laboratory results. At the optimal operating conditions of the nanocatalyst production and Ae inactivation process, the Ascaris ova showed genomic damage to the point that no cell reparation was possible showing that this advanced oxidation process was highly efficient for inactivating this pathogen.

Degradation of ampicillin antibiotic by electrochemical processes: evaluation of antimicrobial activity of treated water.

PubMed

Vidal, Jorge; Huiliñir, Cesar; Santander, Rocío; Silva-Agredo, Javier; Torres-Palma, Ricardo A; Salazar, Ricardo

2018-05-17

Ampicillin (AMP) is an antibiotic widely used in hospitals and veterinary clinics around the world for treating infections caused by bacteria. Therefore, it is common to find traces of this antibiotic in wastewater from these entities. In this work, we studied the mineralization of this antibiotic in solution as well as the elimination of its antimicrobial activity by comparing different electrochemical advanced oxidation processes (EAOPs), namely electro-oxidation with hydrogen peroxide (EO-H 2 O 2 ), electro-Fenton (EF), and photo electro-Fenton (PEF). With PEF process, a high degradation, mineralization, and complete elimination of antimicrobial activity were achieved in 120-min electrolysis with high efficiency. In the PEF process, fast mineralization rate is caused by hydroxyl radicals (·OH) that are generated in the bulk, on the anode surface, by UV radiation, and most importantly, by the direct photolysis of complexes formed between Fe 3+ and some organic intermediates. Moreover, some products and intermediates formed during the degradation of the antibiotic Ampicillin, such as inorganic ions, carboxylic acids, and aromatic compounds, were determined by photometric and chromatographic methods. An oxidation pathway is proposed for the complete conversion to CO 2 .

Effects of Temperature and Acidic Pre-Treatment on Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon

EPA Science Inventory

Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the pH ...

Effects on temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon

EPA Science Inventory

Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the p...

Repeated oxidative degradation of methyl orange through bio-electro-Fenton in bioelectrochemical system (BES).

PubMed

Ling, Ting; Huang, Bin; Zhao, Mingxing; Yan, Qun; Shen, Wei

2016-03-01

Composite Fe2O3/ACF electrode facilitated methyl orange (MO) oxidative degradation using bio-electro-Fenton in bioelectrochemical system (BES) was investigated. Characterized by both XPS and FT-IR techniques, it was found that the composite Fe2O3/ACF electrode with highest Fe loading capacity of 11.02% could be prepared after the carbon felt was oxidized with nitric acid. Moreover, hydrogen peroxide production reached steadily at 88.63 μmol/L with the external resistance as 100 Ω, cathodic aeration rate at 750 mL/min, and the pH of the bio-electro-Fenton system adjusted to 2. Significantly, not only the electrochemical profiles of the BES reactor as electrochemical impedance spectroscopy (EIS) was bettered, but the MO oxidative degradation could be accomplished for eight repeated batches, with the MO removal efficiency varied slightly from 73.9% to 86.7%. It indicated that the bio-electro-Fenton might be a promising eco-friendly AOP method for Azo-dye wastewater treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Magnetite/Fe-Al-montmorillonite as a Fenton catalyst with efficient degradation of phenol.

PubMed

Wei, Xipeng; Wu, Honghai; Sun, Feng

2017-10-15

A Fe-Al-MPM material assembled from nanosized magnetite and Fe-Al-pillared montmorillonite (Fe-Al-Mt) was characterized by XRD, XPS, BET, SEM and TEM. Fe-Al-Mt was proven to be capable of facilitating the dispersion of magnetite nanoparticles and inhibiting their aggregation. The coupling of Fe-Al-Mt with magnetite in Fe-Al-MPM improved its Fenton catalytic activity. Complete conversion of phenol within 80min with a high TOC removal rate (>78%) was achieved using Fe-Al-MPM as a heterogeneous Fenton catalyst under optimized conditions. The Fenton process first underwent a slow induction reaction, followed by the rapid oxidative decomposition of phenol. The existence of the induction reaction period was attributed to the need for activation of the iron species on the catalyst surfaces, and the duration depended on the solution temperature, pH and catalyst's nature. More importantly, Fe-Al-MPM showed high stability, with a low iron-release even after it was recycled 5 times. The minimal iron-leaching from Fe-Al-MPM was ascribed to the competitive adsorption of the incorporated aluminum and all the iron species for the residual (low ecotoxicity) organic ligands. These organic acids were among the main products that remained at the end of the Fenton process. Also important was the ease of separation of Fe-Al-MPM under a magnetic field. Copyright © 2017 Elsevier Inc. All rights reserved.

Using Fenton Oxidation to Simultaneously Remove Different Estrogens from Cow Manure

PubMed Central

Sun, Minxia; Xu, Defu; Ji, Yuefei; Liu, Juan; Ling, Wanting; Li, Shunyao; Chen, Mindong

2016-01-01

The presence of estrogens in livestock excrement has raised concerns about their potential negative influence on animals and the overall food cycle. This is the first investigation to simultaneously remove estrogens, including estriol (E3), bisphenol A (BPA), diethylstilbestrol (DES), estradiol (E2), and ethinyl estradiol (EE2), from cow manure using a Fenton oxidation technique. Based on the residual concentrations and removal efficiency of estrogens, the Fenton oxidation reaction conditions were optimized as follows: a H2O2 dosage of 2.56 mmol/g, a Fe(II) to H2O2 molar ratio of 0.125 M/M, a solid to water mass ratio of 2 g/mL, an initial pH of 3, and a reaction time of 24 h. Under these conditions, the simultaneous removal efficiencies of E3, BPA, DES, E2, and EE2, with initial concentrations in cow manure of 97.40, 96.54, 100.22, 95.01, and 72.49 mg/kg, were 84.9%, 99.5%, 99.1%, 97.8%, and 84.5%, respectively. We clarified the possible Fenton oxidation reaction mechanisms that governed the degradation of estrogens. We concluded that Fenton oxidation technique could be effective for efficient removal of estrogens in livestock excrement. Results are of great importance for cow manure reuse in agricultural management, and can be used to reduce the threat of environmental estrogens to human health and ecological safety. PMID:27649223

Removal of natural organic matter from drinking water by advanced oxidation processes.

PubMed

Matilainen, Anu; Sillanpää, Mika

2010-06-01

Over the past 10-20years the amount of the natural organic matter (NOM) has been increased in raw water supplies on several areas. The presence of NOM causes many problems in drinking water treatment processes, including: (i) negative effect on water quality by colour, taste and odor problems, (ii) increased coagulant and disinfectant dose requirements (which in turn results increased sludge and potential harmful disinfection by-product formation), (iii) promoted biological growth in distribution system, and (iv) increased levels of complexed heavy metals and adsorbed organic pollutants. Thus, more efficient methods for the removal of NOM have emerged. Among these are advanced oxidation processes (AOPs). These include O(3)/H(2)O(2), O(3)/UV, UV/H(2)O(2), TiO(2)/UV, H(2)O(2)/catalyst, Fenton and photo-Fenton prosesses as well as ultrasound. In the present work, an overview of the recent research studies dealing with AOP methods for the removal of NOM and related compounds from drinking water is presented.

Influence of pretreatment with Fenton's reagent on biogas production and methane yield from lignocellulosic biomass.

PubMed

Michalska, Karina; Miazek, Krystian; Krzystek, Liliana; Ledakowicz, Stanisław

2012-09-01

Biomass from Miscanthus giganteus, Sida hermaphrodita and Sorghum Moensch was treated with Fenton's reagent for 2 hours under optimal conditions (pH=3, mass ratio of [Fe(2+)]:[H(2)O(2)] equals 1:25 for Miscanthus and Sorghum and 1:15 for Sida). The degrees of delignification were 30.3%, 62.3% and 48.1% for the three plant species, respectively. The volatile fatty acids concentration after chemical pretreatment was high enough for production of biogas with a high methane content. Combined chemical oxidation and enzymatic hydrolysis with cellulase and cellobiase led to glucose contents of above 4 g/L. Among the tested plants, the highest biogas production (25.2 Ndm(3)/kg TS fed) with a 75% methane content was obtained with Sorghum Moensch. The results of the three-step process of biomass degradation show the necessity of applying a chemical pretreatment such as oxidation with Fenton's reagent. Moreover, the coagulation of residual Fe(3+) ions is not required for high biogas production. Copyright © 2012 Elsevier Ltd. All rights reserved.

Functional kaolin supported nanoscale zero-valent iron as a Fenton-like catalyst for the degradation of Direct Black G.

PubMed

Lin, Jiajiang; Sun, Mengqiang; Liu, Xinwen; Chen, Zuliang

2017-10-01

Kaolin supported nanoscale zero-valent iron (K-nZVI) is synthesized and applied as the Fenton-like oxidation catalyst to degrade a model azo dye, Direct Black G (DBG). The characterization of K-nZVI by the high resolution transmission electronmicroscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Energy Diffraction Spectrum (EDS) and X-ray diffraction (XRD) show that kaolin as a support material not only reduces the aggregation of zero-valent iron (nZVI) but also facilitates the Fenton-like oxidation by increasing the local concentration of DBG in the vicinity of nZVI. Pseudo first-order and pseudo second-order kinetic models are employed to reveal the adsorption and degradation of the DBG using K-nZVI as the catalyst. A better fit with pseudo second-order model for the adsorption process and equal excellent fits with pseudo first-order and pseudo second-order models for the degradation process are observed; the adsorption process is found to be the rate limiting step for overall reactions. The adsorption, evaluated by isotherms and thermodynamic parameters is a spontaneous and endothermic process. High-performance liquid chromatography-mass spectrometry (LC-MS) analysis was used to test degraded products in the degradation of DGB by K-nZVI. A removal mechanism based on the adsorption and degradation is proposed, including (i) prompt adsorption of DBG onto the K-nZVI surface, and (ii) oxidation of DBG by hydroxyl radicals at the K-nZVI surface. The application of K-nZVI to treat real wastewater containing azo dyes shows excellent degradation efficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Decontamination of unsymmetrical dimethylhydrazine waste water by hydrodynamic cavitation-induced advanced Fenton process.

PubMed

Torabi Angaji, Mahmood; Ghiaee, Reza

2015-03-01

A pilot scale hydrodynamic cavitation (HC) reactor, using iron metal blades, as the heterogeneous catalyst, with no external source of H₂O₂ was developed for catalytic decontamination of unsymmetrical dimethylhydrazine (UDMH) waste water. In situ generation of Fenton reagents suggested an induced advanced Fenton process (IAFP) to explain the enhancing effect of the used catalyst in the HC process. The effects of the applied catalyst, pH of the initial solution (1.0-9.7), initial UDMH concentration (2-15 mg/l), inlet pressure (5.5-7.8bar), and downstream pressure (2-6 bar), have been investigated. The results showed that the highest cavitation yield can be obtained at pH 3 and initial UDMH concentration of 10mg/l. Also, an increase in the inlet pressure would lead to an increase in the extent of UDMH degradation. In addition, the optimum value of 3 bar was determined for the downstream pressure that resulted to 98.6% degradation of UDMH after 120 min of processing time. Neither n-nitrosodimethylamine (NDMA) nor any other toxic byproduct (/end-product) was observed in the investigated samples. Formic acid and acetic acid, as well as nitromethane, were identified as oxidation by-products. The present work has conclusively established that hydrodynamic cavitation in combination with Fenton's chemistry can be effectively used for the degradation of UDMH. Copyright © 2014 Elsevier B.V. All rights reserved.

Iron crystallization in a fluidized-bed Fenton process.

PubMed

Boonrattanakij, Nonglak; Lu, Ming-Chun; Anotai, Jin

2011-05-01

The mechanisms of iron precipitation and crystallization in a fluidized-bed reactor were investigated. Within the typical Fenton's reagent dosage and pH range, ferric ions as a product from ferrous ion oxidation would be supersaturated and would subsequently precipitate out in the form of ferric hydroxide after the initiation of the Fenton reaction. These precipitates would simultaneously crystallize onto solid particles in a fluidized-bed Fenton reactor if the precipitation proceeded toward heterogeneous nucleation. The heterogeneous crystallization rate was controlled by the fluidized material type and the aging/ripening period of the crystallites. Iron crystallization onto the construction sand was faster than onto SiO(2), although the iron removal efficiencies at 180 min, which was principally controlled by iron hydroxide solubility, were comparable. To achieve a high iron removal rate, fluidized materials have to be present at the beginning of the Fenton reaction. Organic intermediates that can form ferro-complexes, particularly volatile fatty acids, can significantly increase ferric ion solubility, hence reducing the crystallization performance. Therefore, the fluidized-bed Fenton process will achieve exceptional performance with respect to both organic pollutant removal and iron removal if it is operated with the goal of complete mineralization. Crystallized iron on the fluidized media could slightly retard the successive crystallization rate; thus, it is necessary to continuously replace a portion of the iron-coated bed with fresh media to maintain iron removal performance. The iron-coated construction sand also had a catalytic property, though was less than those of commercial goethite. Copyright © 2011 Elsevier Ltd. All rights reserved.

Optimization of combined in-vessel composting process and chemical oxidation for remediation of bottom sludge of crude oil storage tanks.

PubMed

Koolivand, Ali; Naddafi, Kazem; Nabizadeh, Ramin; Saeedi, Reza

2017-07-31

In this research, removal of petroleum hydrocarbons from oily sludge of crude oil storage tanks was investigated under the optimized conditions of in-vessel composting process and chemical oxidation with H 2 O 2 and Fenton. After determining the optimum conditions, the sludge was pre-treated with the optimum state of the oxidation process. Then, the determined optimum ratios of the sludge to immature compost were composted at a C:N:P ratio of 100:5:1 and moisture content of 55% for a period of 10 weeks. Finally, both pre-treated and composted mixtures were again oxidized with the optimum conditions of the oxidants. Results showed that total petroleum hydrocarbons (TPH) removal of the 1:8 and 1:10 composting reactors which were pre-treated with H 2 O 2 were 88.34% and 90.4%, respectively. In addition, reduction of TPH in 1:8 and 1:10 composting reactors which were pre-treated with Fenton were 83.90% and 84.40%, respectively. Without applying the pre-treatment step, the composting reactors had a removal rate of about 80%. Therefore, pre-treatment of the reactors increased the TPH removal. However, post-oxidation of both pre-treated and composted mixtures reduced only 13-16% of TPH. Based on the results, remarkable overall removal of TPH (about 99%) was achieved by using chemical oxidation and subsequent composting process. The study showed that chemical oxidation with H 2 O 2 followed by in-vessel composting is a viable choice for the remediation of the sludge.

Case study of the application of Fenton process to highly polluted wastewater from power plant.

PubMed

Pliego, Gema; Zazo, Juan A; Casas, Jose A; Rodriguez, Juan J

2013-05-15

This work investigates the application of Fenton process to the treatment of a highly polluted industrial wastewater resulting from the pipeline cleaning in a power plant. This effluent is characterized by a high chemical oxygen demand (COD>40 g/L), low biodegradability and quite a high iron concentration (around 3g/L) this coming from pipeline corrosion. The effect of the initial reaction temperature (between 50 and 90 °C) and the way of feeding H2O2 on the mineralization percentage and the efficiency of H2O2 consumption has been analyzed. With the stoichiometric amount of H2O2 relative to initial COD, fed in continuous mode, more than 90% COD reduction was achieved at 90 °C. That was accompanied by a dramatic improvement of the biodegradability. Thus, a combined treatment based on semicontinuous high-temperature Fenton oxidation (SHTF) and conventional aerobic biological treatment would allow fulfilling the COD and ecotoxicity regional limits for industrial wastewaters into de municipal sewer system. For the sake of comparison, catalytic wet air oxidation was also tested with poor results (less than 30% COD removal at 140 °C and 8 atm oxygen pressure). Copyright © 2013 Elsevier B.V. All rights reserved.

Degradation of the insecticide propoxur by electrochemical advanced oxidation processes using a boron-doped diamond/air-diffusion cell.

PubMed

Guelfi, Diego Roberto Vieira; Gozzi, Fábio; Sirés, Ignasi; Brillas, Enric; Machulek, Amílcar; de Oliveira, Silvio César

2017-03-01

A solution with 0.38 mM of the pesticide propoxur (PX) at pH 3.0 has been comparatively treated by electrochemical oxidation with electrogenerated H 2 O 2 (EO-H 2 O 2 ), electro-Fenton (EF), and photoelectro-Fenton (PEF). The trials were carried out with a 100-mL boron-doped diamond (BDD)/air-diffusion cell. The EO-H 2 O 2 process had the lowest oxidation ability due to the slow reaction of intermediates with • OH produced from water discharge at the BDD anode. The EF treatment yielded quicker mineralization due to the additional • OH formed between added Fe 2+ and electrogenerated H 2 O 2 . The PEF process was the most powerful since it led to total mineralization by the combined oxidative action of hydroxyl radicals and UVA irradiation. The PX decay agreed with a pseudo-first-order kinetics in EO-H 2 O 2 , whereas in EF and PEF, it obeyed a much faster pseudo-first-order kinetics followed by a much slower one, which are related to the oxidation of its Fe(II) and Fe(III) complexes, respectively. EO-H 2 O 2 showed similar oxidation ability within the pH range 3.0-9.0. The effect of current density and Fe 2+ and substrate contents on the performance of the EF process was examined. Two primary aromatic products were identified by LC-MS during PX degradation.

Heterogeneous fenton catalysts based on activated carbon and related materials.

PubMed

Navalon, Sergio; Dhakshinamoorthy, Amarajothi; Alvaro, Mercedes; Garcia, Hermenegildo

2011-12-16

The Fenton reaction is widely used for remediation of waste water and for the degradation of organic pollutants in water. Currently, there is considerable interest to convert the classical Fenton reaction, which consumes stoichiometric amounts of iron(II) salts, into a catalytic process that is promoted by a solid. This review describes the work that has used carbonaceous materials either directly as catalysts or, more frequently, as a large-area support for catalytically activated transition metals or metal-oxide nanoparticles. The interest in this type of catalyst derives from the wide use of carbon in conventional water treatments and the wide applicability of the Fenton reaction. After two general sections that illustrate the scope and background of Fenton chemistry, the review describes the activity of activated carbon in the absence or presence of metal-containing particles. The last sections of the review focus on different types of carbonaceous materials, such as carbon nanotubes and diamond nanoparticles. The review concludes with a section that anticipates future developments in this area, which are aimed at overcoming the current limitations of low activity and occurrence of metal leaching. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fenton-driven regeneration of MTBE-spent granular activated carbon - Effects of particle size and Iron Amendment Procedures

EPA Science Inventory

Fenton-driven regeneration of spent granular activated carbon (GAC) is a technology being developed to regenerate organic contaminant-spent GAC. Here, the effect of GAC particle size (>2 mm to <0.35 mm) on Fenton-driven oxidation of methyl tert-butyl ether (MTBE)-spent GAC was ev...

Coupling of solar photoelectro-Fenton with a BDD anode and solar heterogeneous photocatalysis for the mineralization of the herbicide atrazine.

PubMed

Garza-Campos, Benjamín R; Guzmán-Mar, Jorge Luis; Reyes, Laura Hinojosa; Brillas, Enric; Hernández-Ramírez, Aracely; Ruiz-Ruiz, Edgar J

2014-02-01

Here, the synergetic effect of coupling solar photoelectro-Fenton (SPEF) and solar heterogeneous photocatalysis (SPC) on the mineralization of 200mL of a 20mg L(-1) atrazine solution, prepared from the commercial herbicide Gesaprim, at pH 3.0 was studied. Uniform, homogeneous and adherent anatase-TiO2 films onto glass spheres of 5mm diameter were prepared by the sol-gel dip-coating method and used as catalyst for SPC. However, this procedure yielded a poor removal of the substrate because of the low oxidation ability of positive holes and OH formed at the catalyst surface to destroy it. Atrazine decay was improved using anodic oxidation (AO), electro-Fenton (EF), SPEF and coupled SPEF-SPC at 100mA. The electrolytic cell contained a boron-doped diamond (BDD) anode and H2O2 was generated at a BDD cathode fed with an air flow. The removal and mineralization of atrazine increased when more oxidizing agents were generated in the sequence AO

Fenton Oxidation Kinetics and Intermediates of Nonylphenol Ethoxylates

PubMed Central

Cui, Kai; Yi, Hao; Zhou, Zi-jian; Zhuo, Qiong-fang; Bing, Yong-xin; Guo, Qing-wei; Xu, Zhen-cheng

2014-01-01

Abstract Removal of nonylphenol ethoxylates (NPEOs) in aqueous solution by Fenton oxidation process was studied in a laboratory-scale batch reactor. Operating parameters, including initial pH temperature, hydrogen peroxide, and ferrous ion dosage, were thoroughly investigated. Maximum NPEOs reduction of 84% was achieved within 6 min, under an initial pH of 3.0, 25°C, an H2O2 dosage of 9.74×10−3 M, and a molar ratio of [H2O2]/[Fe2+] of 3. A modified pseudo-first-order kinetic model was found to well represent experimental results. Correlations of reaction rate constants and operational parameters were established based on experimental data. Results indicated that the Fenton oxidation rate and removal efficiency were more dependent on the dosage of H2O2 than Fe2+, and the apparent activation energy (ΔE) was 17.5 kJ/mol. High-performance liquid chromatography and gas chromatograph mass spectrometer analytical results indicated degradation of NPEOs obtained within the first 2 min stepwise occurred by ethoxyl (EO) unit shortening. Long-chain NPEOs mixture demonstrated a higher degradation rate than shorter-chain ones. Nonylphenol (NP), short-chain NPEOs, and NP carboxyethoxylates were identified as the primary intermediates, which were mostly further degraded. PMID:24868141

Preliminary Feasibility Study of Benzo(a)Pyrene Oxidative Degradation by Fenton Treatment

PubMed Central

Homem, Vera; Dias, Zélia; Santos, Lúcia; Alves, Arminda

2009-01-01

Polycyclic aromatic hydrocarbons (PAHs) are considered priority compounds due to their toxic and carcinogenic nature. The concern about water contamination and the consequent human exposure has encouraged the development of new methods for PAHs removal. The purpose of this work was to study the feasibility of a degradation process of benzo(a)pyrene (BaP) in aqueous matrices by oxidation with Fenton reagent. A laboratory unit was designed to optimize the factors which may influence the process: pH (3.5 to 6.0), temperature (30 to 70°C), H2O2 (20 to 150 mg L−1), Fe2+ concentration (2.75 to 5.50 mg L−1), and the initial concentration of the pollutant (10 to 100 μg L−1). The pH did not influence significantly the results in the range studied. An increase in temperature from 30 to 70°C improved the removal efficiency from 90% to 100%. The same effect was observed for ferrous ion concentrations from 2.75 to 5.50 mg L−1 (increase from 78% to 100% removal). The H2O2 concentration played a double role during the process: from 20 to 50 mg L−1 an increase in the removal efficiency was achieved, but for higher concentrations (>50 mg L−1) the degradation is lower. This study proved that the degradation of benzo(a)pyrene by Fenton's reagent is a viable process. PMID:19936125

How does intensification influence the operational and environmental performance of photo-Fenton processes at acidic and circumneutral pH.

PubMed

Salazar, Luis Miguel; Grisales, Claudia Mildred; Garcia, Dorian Prato

2018-05-31

This study evaluates the technical, economical, and environmental impact of sodium persulfate (Na 2 S 2 O 8 ) as an enhancing agent in a photo-Fenton process within a solar-pond type reactor (SPR). Photo-Fenton (PF) and photo-Fenton intensified with the addition of persulfate (PFPS) processes decolorize 97% the azo dye direct blue 71 (DB71) and allow producing a highly biodegradable effluent. Intensification with persulfate allowed reducing treatment time in 33% (from 120 to 80 min) and the consumption of chemical auxiliaries needed for pH adjustment. Energy, reagents, and chemical auxiliaries are still and environmental hotspot for PF and PFPS; however, it is worth mentioning that their environmental footprint is lower than that observed for compound parabolic concentrator (CPC)-type reactors. A life-cycle assessment (LCA) confirms that H 2 O 2 , NaOH, and energy consumption are the variables with the highest impact from an environmental standpoint. The use of persulfate reduced the relative impact in 1.2 to 12% in 12 of the 18 environmental categories studied using the ReCiPe method. The PFPS process emits 1.23 kg CO 2 (CO 2 -Eqv/m 3 treated water). On the other hand, the PF process emits 1.28 kg CO 2 (CO 2 -Eqv/m 3 treated water). Process intensification, chemometric techniques, and the use of SPRs minimize the impact of some barriers (reagent and energy consumption, technical complexity of reactors, pressure drops, dirt on the reflecting surfaces, fragility of reactor materials), limiting the application of advanced oxidation systems at an industrial level, and decrease treatment cost as well as potential environmental impacts associated with energy and reagents consumption. Treatment costs for PF processes (US$0.78/m 3 ) and PFPS processes (US$0.63/m 3 ) were 20 times lower than those reported for photo-Fenton processes in CPC-type reactors.

Enhanced heterogeneous photo-Fenton process modified by magnetite and EDDS: BPA degradation.

PubMed

Huang, Wenyu; Luo, Mengqi; Wei, Chaoshuai; Wang, Yinghui; Hanna, Khalil; Mailhot, Gilles

2017-04-01

In this research, magnetite and ethylenediamine-N,N'-disuccinic acid (EDDS) are used in a heterogeneous photo-Fenton system in order to find a new way to remove organic contaminants from water. Influence of different parameters including magnetite dosage, EDDS concentration, H 2 O 2 concentration, and pH value were evaluated. The effect of different radical species including HO · and HO 2 · /O 2 ·- was investigated by addition of different scavengers into the system. The addition of EDDS improved the heterogeneous photo-Fenton degradation of bisphenol A (BPA) through the formation of photochemically efficient Fe-EDDS complex. This effect is dependent on the H 2 O 2 and EDDS concentrations and pH value. The high performance observed at pH 6.2 could be explained by the ability of O 2 ·- to generate Fe(II) from Fe(III) species reduction. GC-MS analysis suggested that the cleavage of the two benzene rings is the first degradation step followed by oxidation leading to the formation of the benzene derivatives. Then, the benzene ring was opened due to the attack of HO · radicals producing short-chain organic compounds of low molecular weight like glycerol and ethylene glycol. These findings regarding the capability of EDDS/magnetite system to promote heterogeneous photo-Fenton oxidation have important practical implications for water treatment technologies.

Oxidation of atrazine in aqueous media by solar- enhanced Fenton-like process involving persulfate and ferrous ion.

PubMed

Khandarkhaeva, Marina; Batoeva, Agniya; Aseev, Denis; Sizykh, Marina; Tsydenova, Oyuna

2017-03-01

The oxidation of s-triazines (using atrazine (ATZ) as a model compound) by a solar-enhanced Fenton-like process involving persulfate and ferrous ion was studied. A flow-through tubular photoreactor was employed for the experiments. The solar-enhanced oxidative system involving ferrous ion and persulfate (Solar/S 2 O 8 2- /Fe 2+ ) showed the highest ATZ degradation efficiency when compared with other treatments (unactivated S 2 O 8 2- , Solar - sunlight only, S 2 O 8 2- /Fe 2+ , Solar/S 2 O 8 2- ). Complete degradation of ATZ and 20% reduction in total organic carbon (TOC) content were observed after 30min of the treatment. The in situ generated • ОН and SO 4 -• radicals were shown to be involved in ATZ oxidation using the radical scavengers methanol and tert-butyl alcohol. Furthermore, iron compounds were shown to act not only as catalysts but also as photo-sensitizers, as the introduction of ferrous ion into the reaction mixture led to an increased absorbance of the solution and expansion of the absorption spectrum into the longer wavelength spectral region. Copyright © 2016 Elsevier Inc. All rights reserved.

Treatment of amoxicillin by O3/Fenton process in a rotating packed bed.

PubMed

Li, Mo; Zeng, Zequan; Li, Yingwen; Arowo, Moses; Chen, Jianfeng; Meng, Hong; Shao, Lei

2015-03-01

In this study, simulated amoxicillin wastewater was treated by the O3/Fenton process in a rotating packed bed (RPB) and the results were compared with the Fenton process and the O3 followed by Fenton (O3 + Fenton) process. The chemical oxygen demand (COD) removal rate and the ratio of 5-day biological oxygen demand to chemical oxygen demand (BOD5/COD) in the O3/Fenton process were approximately 17% and 26%, respectively, higher than those in the O3 + Fenton process with an initial pH of 3. The COD removal rate of the amoxicillin solution reached maximum at the Fe(II) concentration of 0.6 mM, temperature of 25 °C, rotation speed of 800 rpm and initial pH of 3. The BOD5/COD of the amoxicillin solution increased from 0 to 0.38 after the solution was treated by the O3/Fenton process. Analysis of the intermediates indicated that the pathway of amoxicillin degradation in the O3/Fenton process was similar to that in the O3 + Fenton process. Contrast experiment results showed that amoxicillin degradation was significantly intensified in the RPB. Copyright © 2014 Elsevier Ltd. All rights reserved.

Removal of azo dye using Fenton and Fenton-like processes: Evaluation of process factors by Box-Behnken design and ecotoxicity tests.

PubMed

Fernandes, Neemias Cintra; Brito, Lara Barroso; Costa, Gessyca Gonçalves; Taveira, Stephânia Fleury; Cunha-Filho, Marcílio Sérgio Soares; Oliveira, Gisele Augusto Rodrigues; Marreto, Ricardo Neves

2018-06-06

The conventional treatment of textile effluents is usually inefficient in removing azo dyes and can even generate more toxic products than the original dyes. The aim of the present study was to optimize the process factors in the degradation of Disperse Red 343 by Fenton and Fenton-like processes, as well as to investigate the ecotoxicity of the samples treated under optimized conditions. A Box-Behnken design integrated with the desirability function was used to optimize dye degradation, the amount of residual H 2 O 2 [H 2 O 2residual ], and the ecotoxicity of the treated samples (lettuce seed, Artemia salina, and zebrafish in their early-life stages). Dye degradation was affected only by catalyst concentration [Fe] in both the Fenton and Fenton-like processes. In the Fenton reaction, [H 2 O 2residual ] was significantly affected by initial [H 2 O 2 ] and its interaction with [Fe]; however, in the Fenton-like reaction, it was affected by initial [H 2 O 2 ] only. A. salina mortality was affected by different process factors in both processes, which suggests the formation of different toxic products in each process. The desirability function was applied to determine the best process parameters and predict the responses, which were confirmed experimentally. Optimal conditions facilitated the complete degradation of the dye without [H 2 O 2residual ] or toxicity for samples treated with the Fenton-like process, whereas the Fenton process induced significant mortality for A. salina. Results indicate that the Fenton-like process is superior to the Fenton reaction to degrade Disperse Red 343. Copyright © 2018 Elsevier B.V. All rights reserved.

Insight into the Mechanism of Graphene Oxide Degradation via the Photo-Fenton Reaction

PubMed Central

2015-01-01

Graphene represents an attractive two-dimensional carbon-based nanomaterial that holds great promise for applications such as electronics, batteries, sensors, and composite materials. Recent work has demonstrated that carbon-based nanomaterials are degradable/biodegradable, but little work has been expended to identify products formed during the degradation process. As these products may have toxicological implications that could leach into the environment or the human body, insight into the mechanism and structural elucidation remain important as carbon-based nanomaterials become commercialized. We provide insight into a potential mechanism of graphene oxide degradation via the photo-Fenton reaction. We have determined that after 1 day of treatment intermediate oxidation products (with MW 150–1000 Da) were generated. Upon longer reaction times (i.e., days 2 and 3), these products were no longer present in high abundance, and the system was dominated by graphene quantum dots (GQDs). On the basis of FTIR, MS, and NMR data, potential structures for these oxidation products, which consist of oxidized polycyclic aromatic hydrocarbons, are proposed. PMID:24860637

Synergistic efficiency of the desilication of brackish underground water in Saudi Arabia by coupling γ-radiation and Fenton process: Membrane scaling prevention in reverse osmosis process

NASA Astrophysics Data System (ADS)

Aljohani, Mohammed S.

2017-12-01

One of the main water resources in arid Saudi Arabia is underground water. However, this brackish water has high silica content which can cause a recalcitrant deposit on the membrane in the reverse osmosis units during its desalination. In this study, we examined the synergistic efficiency of the removal of silica from the Buwaib water sample, when combining two advanced oxidation processes, γ-irradiation and the Fenton process, using hydrogen peroxide and zero valent metal iron as source of Fe3+. This latter adsorbs effectively on silica and co-precipitate. The influence of absorbed dose, iron dosage and pH effect were investigated. This preliminary study showed that these attractive and effective hybrid processes are very efficient in removing silica.

Reduction of non-Betalactam Antibiotics COD by Combined Coagulation and Advanced Oxidation Processes.

PubMed

Yazdanbakhsh, Ahmad Reza; Mohammadi, Amir Sheikh; Alinejad, Abdol Azim; Hassani, Ghasem; Golmohammadi, Sohrab; Mohseni, Seyed Mohsen; Sardar, Mahdieh; Sarsangi, Vali

2016-11-01

  The present study evaluates the reduction of antibiotic COD from wastewater by combined coagulation and advanced oxidation processes (AOPS). The reduction of Azithromycin COD by combined coagulation and Fenton-like processes reached a maximum 96.9% at a reaction time of 30 min, dosage of ferric chloride 120 mg/L, dosages of Fe0 and H2O2of 0.36mM/L and 0.38 mM/L, respectively. Also, 97.9% of Clarithromycin COD reduction, was achieved at a reaction time of 30 min, dosage of ferric chloride 120 mg/L, dosages of Fe0 and H2O2 of 0.3 mM/L and 0.3mM/L, respectively. The results of kinetic studies were best fitted to the pseudo first order equation. The results showed a higher rate constant value for combined coagulation and Fenton-like processes [(kap = 0.022 min-1 and half-life time of 31.5 min for Azithromycin) and (kap = 0.023 min-1 and half-life time of 30.1 min for Clarithromycin)].

The nitroxide Tempo inhibits hydroxyl radical production from the Fenton-like reaction of iron(II)-citrate with hydrogen peroxide.

PubMed

Shi, Fengqiang; Zhang, Peifeng; Mao, Yujia; Wang, Can; Zheng, Meiqing; Zhao, Zhongwei

2017-01-29

In vivo physiological ligand citrate can bind iron(II) ions to form the iron(II)-citrate complex. Inhibition of hydroxyl radical (OH) production from the Fenton-like reaction of iron(II)-citrate with H 2 O 2 is biologically important, as this reaction may account for one of the mechanisms of the labile iron pool in vivo to induce oxidative stress and pathological conditions. Nitroxides have promising potentials as therapeutic antioxidants. However, there are controversial findings indicating that they not only act as antioxidants but also as pro-oxidants when engaged in Fenton reactions. Although the underlying mechanisms are proposed to be the inhibition or enhancement of the OH production by nitroxides, the proposed elucidations are only based on assessing biological damages and not demonstrated directly by measuring the OH production in the presence of nitroxides. In this study, therefore, we employed EPR and fluorescence spectroscopies to show direct evidence that nitroxide 2,2,6,6-tetramethyl-piperidine-1-oxyl (Tempo) inhibited OH production from the Fenton-like reaction of iron(II)-citrate with H 2 O 2 by up to 90%. We also demonstrated spectrophotometrically, for the first time, that this inhibition was due to oxidation of the iron(II)-citrate by Tempo with a stoichiometry of Tempo:Iron(III)-citrate = 1.1:1.0. A scheme was proposed to illustrate the roles of nitroxides engaged in Fenton/Fenton-like reactions. Copyright © 2016 Elsevier Inc. All rights reserved.

Degradation of folic acid wastewater by electro-Fenton with three-dimensional electrode and its kinetic study

PubMed Central

Xiaochao, Gu; Jin, Tian; Xiaoyun, Li; Bin, Zhou; Xujing, Zheng; Jin, Xu

2018-01-01

The three-dimensional electro-Fenton method was used in the folic acid wastewater pretreatment process. In this study, we researched the degradation of folic acid and the effects of different parameters such as the air sparging rate, current density, pH and reaction time on chemical oxygen demand (COD) removal in folic acid wastewater. A four-level and four-factor orthogonal test was designed and optimal reaction conditions to pretreat folic acid wastewater by three-dimensional electrode were determined: air sparge rate 0.75 l min−1, current density 10.26 mA cm−2, pH 5 and reaction time 90 min. Under these conditions, the removal of COD reached 94.87%. LC-MS results showed that the electro-Fenton method led to an initial folic acid decomposition into p-aminobenzoyl-glutamic acid (PGA) and xanthopterin (XA); then part of the XA was oxidized to pterine-6-carboxylic acid (PCA) and the remaining part of XA was converted to pterin and carbon dioxide. The kinetics analysis of the folic acid degradation process during pretreatment was carried out by using simulated folic acid wastewater, and it could be proved that the degradation of folic acid by using the three-dimensional electro-Fenton method was a second-order reaction process. This study provided a reference for industrial folic acid treatment. PMID:29410807

Ultradispersed Cobalt Ferrite Nanoparticles Assembled in Graphene Aerogel for Continuous Photo-Fenton Reaction and Enhanced Lithium Storage Performance

NASA Astrophysics Data System (ADS)

Qiu, Bocheng; Deng, Yuanxin; Du, Mengmeng; Xing, Mingyang; Zhang, Jinlong

2016-07-01

The Photo-Fenton reaction is an advanced technology to eliminate organic pollutants in environmental chemistry. Moreover, the conversion rate of Fe3+/Fe2+ and utilization rate of H2O2 are significant factors in Photo-Fenton reaction. In this work, we reported three dimensional (3D) hierarchical cobalt ferrite/graphene aerogels (CoFe2O4/GAs) composites by the in situ growing CoFe2O4 crystal seeds on the graphene oxide (GO) followed by the hydrothermal process. The resulting CoFe2O4/GAs composites demonstrated 3D hierarchical pore structure with mesopores (14~18 nm), macropores (50~125 nm), and a remarkable surface area (177.8 m2 g-1). These properties endowed this hybrid with the high and recyclable Photo-Fenton activity for methyl orange pollutant degradation. More importantly, the CoFe2O4/GAs composites can keep high Photo-Fenton activity in a wide pH. Besides, the CoFe2O4/GAs composites also exhibited excellent cyclic performance and good rate capability. The 3D framework can not only effectively prevent the volume expansion and aggregation of CoFe2O4 nanoparticles during the charge/discharge processes for Lithium-ion batteries (LIBs), but also shorten lithium ions and electron diffusion length in 3D pathways. These results indicated a broaden application prospect of 3D-graphene based hybrids in wastewater treatment and energy storage.

Ultradispersed Cobalt Ferrite Nanoparticles Assembled in Graphene Aerogel for Continuous Photo-Fenton Reaction and Enhanced Lithium Storage Performance.

PubMed

Qiu, Bocheng; Deng, Yuanxin; Du, Mengmeng; Xing, Mingyang; Zhang, Jinlong

2016-07-04

The Photo-Fenton reaction is an advanced technology to eliminate organic pollutants in environmental chemistry. Moreover, the conversion rate of Fe(3+)/Fe(2+) and utilization rate of H2O2 are significant factors in Photo-Fenton reaction. In this work, we reported three dimensional (3D) hierarchical cobalt ferrite/graphene aerogels (CoFe2O4/GAs) composites by the in situ growing CoFe2O4 crystal seeds on the graphene oxide (GO) followed by the hydrothermal process. The resulting CoFe2O4/GAs composites demonstrated 3D hierarchical pore structure with mesopores (14~18 nm), macropores (50~125 nm), and a remarkable surface area (177.8 m(2 )g(-1)). These properties endowed this hybrid with the high and recyclable Photo-Fenton activity for methyl orange pollutant degradation. More importantly, the CoFe2O4/GAs composites can keep high Photo-Fenton activity in a wide pH. Besides, the CoFe2O4/GAs composites also exhibited excellent cyclic performance and good rate capability. The 3D framework can not only effectively prevent the volume expansion and aggregation of CoFe2O4 nanoparticles during the charge/discharge processes for Lithium-ion batteries (LIBs), but also shorten lithium ions and electron diffusion length in 3D pathways. These results indicated a broaden application prospect of 3D-graphene based hybrids in wastewater treatment and energy storage.

Ultradispersed Cobalt Ferrite Nanoparticles Assembled in Graphene Aerogel for Continuous Photo-Fenton Reaction and Enhanced Lithium Storage Performance

PubMed Central

Qiu, Bocheng; Deng, Yuanxin; Du, Mengmeng; Xing, Mingyang; Zhang, Jinlong

2016-01-01

The Photo-Fenton reaction is an advanced technology to eliminate organic pollutants in environmental chemistry. Moreover, the conversion rate of Fe3+/Fe2+ and utilization rate of H2O2 are significant factors in Photo-Fenton reaction. In this work, we reported three dimensional (3D) hierarchical cobalt ferrite/graphene aerogels (CoFe2O4/GAs) composites by the in situ growing CoFe2O4 crystal seeds on the graphene oxide (GO) followed by the hydrothermal process. The resulting CoFe2O4/GAs composites demonstrated 3D hierarchical pore structure with mesopores (14~18 nm), macropores (50~125 nm), and a remarkable surface area (177.8 m2 g−1). These properties endowed this hybrid with the high and recyclable Photo-Fenton activity for methyl orange pollutant degradation. More importantly, the CoFe2O4/GAs composites can keep high Photo-Fenton activity in a wide pH. Besides, the CoFe2O4/GAs composites also exhibited excellent cyclic performance and good rate capability. The 3D framework can not only effectively prevent the volume expansion and aggregation of CoFe2O4 nanoparticles during the charge/discharge processes for Lithium-ion batteries (LIBs), but also shorten lithium ions and electron diffusion length in 3D pathways. These results indicated a broaden application prospect of 3D-graphene based hybrids in wastewater treatment and energy storage. PMID:27373343

Treatment efficiency and economic feasibility of biological oxidation, membrane filtration and separation processes, and advanced oxidation for the purification and valorization of olive mill wastewater.

PubMed

Ioannou-Ttofa, L; Michael-Kordatou, I; Fattas, S C; Eusebio, A; Ribeiro, B; Rusan, M; Amer, A R B; Zuraiqi, S; Waismand, M; Linder, C; Wiesman, Z; Gilron, J; Fatta-Kassinos, D

2017-05-01

Olive mill wastewater (OMW) is a major waste stream resulting from numerous operations that occur during the production stages of olive oil. The resulting effluent contains various organic and inorganic contaminants and its environmental impact can be notable. The present work aims at investigating the efficiency of (i) jet-loop reactor with ultrafiltration (UF) membrane system (Jacto.MBR), (ii) solar photo-Fenton oxidation after coagulation/flocculation pre-treatment and (iii) integrated membrane filtration processes (i.e. UF/nanofiltration (NF)) used for the treatment of OMW. According to the results, the efficiency of the biological treatment was high, equal to 90% COD and 80% total phenolic compounds (TPh) removal. A COD removal higher than 94% was achieved by applying the solar photo-Fenton oxidation process as post-treatment of coagulation/flocculation of OMW, while the phenolic fraction was completely eliminated. The combined UF/NF process resulted in very high conductivity and COD removal, up to 90% and 95%, respectively, while TPh were concentrated in the NF concentrate stream (i.e. 93% concentration). Quite important is the fact that the NF concentrate, a valuable and polyphenol rich stream, can be further valorized in various industries (e.g. food, pharmaceutical, etc.). The above treatment processes were found also to be able to reduce the initial OMW phytotoxicity at greenhouse experiments; with the effluent stream of solar photo-Fenton process to be the least phytotoxic compared to the other treated effluents. A SWOT (Strength, Weakness, Opportunities, Threats) analysis was performed, in order to determine both the strengths of each technology, as well as the possible obstacles that need to overcome for achieving the desired levels of treatment. Finally, an economic evaluation of the tested technologies was performed in an effort to measure the applicability and viability of these systems at real scale; highlighting that the cost cannot be regarded as a 'cut off criterion', since the most cost-effective option in not always the optimum one. Copyright © 2017 Elsevier Ltd. All rights reserved.

Aluminum and Fenton reaction: how can the reaction be modulated by speciation? A computational study using citrate as a test case.

PubMed

Mujika, Jon I; Dalla Torre, Gabriele; Lopez, Xabier

2018-06-13

The pro-oxidant ability of aluminum is behind many of the potential toxic effects of this exogenous element in the human organism. Although the overall process is still far from being understood at the molecular level, the well known ability of aluminum to promote the Fenton reaction is mediated through the formation of stable aluminum-superoxide radical complexes. However, the properties of metal complexes are highly influenced by the speciation of the metal. In this paper, we investigate the effect that speciation could have on the pro-oxidant activity of aluminum. We choose citrate as a test case, because it is the main low-molecular-mass chelator of aluminum in blood serum, forming very stable aluminum-citrate complexes. The influence of citrate in the interaction of aluminum with the superoxide radical is investigated, determining how the formation of aluminum-citrate complexes affects the promotion of the Fenton reaction. The results indicate that citrate increases the stability of the aluminum-superoxide complexes through the formation of ternary compounds, and that the Fenton reaction is even more favorable when aluminum is chelated to citrate. Nevertheless, our results demonstrate that overall, citrate may prevent the pro-oxidant activity of aluminum: on one hand, in an excess of citrate, the formation of 1 : 2 aluminum-citrate complexes is expected. On the other hand, the chelation of iron by citrate makes the reduction of iron thermodynamically unfavorable. In summary, the results suggest that citrate can have both a promotion and protective role, depending on subtle factors, such as initial concentration, non-equilibrium behavior and the exchange rate of ligands in the first shell of the metals.

Advanced oxidation of real sulfamethoxazole + trimethoprim formulations using different anodes and electrolytes.

PubMed

Murillo-Sierra, Juan C; Sirés, Ignasi; Brillas, Enric; Ruiz-Ruiz, Edgar J; Hernández-Ramírez, Aracely

2018-02-01

A commercial sulfamethoxazole + trimethoprim formulation has been degraded in 0.050 M Na 2 SO 4 at pH 3.0 by electrochemical oxidation with electrogenerated H 2 O 2 (EO-H 2 O 2 ), electro-Fenton (EF), photoelectro-Fenton with a 6-W UVA lamp (PEF) and solar photoelectro-Fenton (SPEF). The tests were performed in an undivided cell with an IrO 2 -based, Pt or boron-doped diamond (BDD) anode and an air-diffusion cathode for H 2 O 2 electrogeneration. The anode material had little effect on the accumulated H 2 O 2 concentration. Both drugs always obeyed a pseudo-first-order decay with low apparent rate constant in EO-H 2 O 2 . Much higher values were found in EF, PEF and SPEF, showing no difference because the main oxidant was always OH formed from Fenton's reaction between H 2 O 2 and added Fe 2+ . The solution mineralization increased in the sequence EO-H 2 O 2  < EF < PEF < SPEF regardless of the anode. The IrO 2 -based and Pt anodes behaved similarly but BDD was always more powerful. In SPEF, similar mineralization profiles were found for all anodes because of the rapid removal of photoactive intermediates by sunlight. About 87% mineralization was obtained as maximum for the powerful SPEF with BDD anode. Addition of Cl - enhanced the decay of both drugs due to their quicker reaction with generated active chlorine, but the formation of persistent chloroderivatives decelerated the mineralization process. Final carboxylic acids like oxalic and oxamic were detected, yielding Fe(III) complexes that remained stable in EF with BDD but were rapidly photolyzed in SPEF with BDD, explaining its superior mineralization ability. Copyright © 2017 Elsevier Ltd. All rights reserved.

A bionic system with Fenton reaction and bacteria as a model for bioprocessing lignocellulosic biomass.

PubMed

Zhang, Kejing; Si, Mengying; Liu, Dan; Zhuo, Shengnan; Liu, Mingren; Liu, Hui; Yan, Xu; Shi, Yan

2018-01-01

The recalcitrance of lignocellulosic biomass offers a series of challenges for biochemical processing into biofuels and bio-products. For the first time, we address these challenges with a biomimetic system via a mild yet rapid Fenton reaction and lignocellulose-degrading bacterial strain Cupriavidus basilensis B-8 (here after B-8) to pretreat the rice straw (RS) by mimicking the natural fungal invasion process. Here, we also elaborated the mechanism through conducting a systematic study of physicochemical changes before and after pretreatment. After synergistic Fenton and B-8 pretreatment, the reducing sugar yield was increased by 15.6-56.6% over Fenton pretreatment alone and 2.7-5.2 times over untreated RS (98 mg g -1 ). Morphological analysis revealed that pretreatment changed the surface morphology of the RS, and the increase in roughness and hydrophilic sites enhanced lignocellulose bioavailability. Chemical components analyses showed that B-8 removed part of the lignin and hemicellulose which caused the cellulose content to increase. In addition, the important chemical modifications also occurred in lignin, 2D NMR analysis of the lignin in residues indicated that the Fenton pretreatment caused partial depolymerization of lignin mainly by cleaving the β- O -4 linkages and by demethoxylation to remove the syringyl (S) and guaiacyl (G) units. B-8 could depolymerize amount of the G units by cleaving the β-5 linkages that interconnect the lignin subunits. A biomimetic system with a biochemical Fenton reaction and lignocellulose-degrading bacteria was confirmed to be able for the pretreatment of RS to enhance enzymatic hydrolysis under mild conditions. The high digestibility was attributed to the destruction of the lignin structure, partial hydrolysis of the hemicellulose and partial surface oxidation of the cellulose. The mechanism of synergistic Fenton and B-8 pretreatment was also explored to understand the change in the RS and the bacterial effects on enzymatic hydrolysis. Furthermore, this biomimetic system offers new insights into the pretreatment of lignocellulosic biomass.

Solar photo-Fenton process on the abatement of antibiotics at a pilot scale: Degradation kinetics, ecotoxicity and phytotoxicity assessment and removal of antibiotic resistant enterococci.

PubMed

Michael, I; Hapeshi, E; Michael, C; Varela, A R; Kyriakou, S; Manaia, C M; Fatta-Kassinos, D

2012-11-01

This work investigated the application of a solar driven advanced oxidation process (solar photo-Fenton), for the degradation of antibiotics at low concentration level (μg L(-1)) in secondary treated domestic effluents at a pilot-scale. The examined antibiotics were ofloxacin (OFX) and trimethoprim (TMP). A compound parabolic collector (CPC) pilot plant was used for the photocatalytic experiments. The process was mainly evaluated by a fast and reliable analytical method based on a UPLC-MS/MS system. Solar photo-Fenton process using low iron and hydrogen peroxide doses ([Fe(2+)](0) = 5 mg L(-1); [H(2)O(2)](0) = 75 mg L(-1)) was proved to be an efficient method for the elimination of these compounds with relatively high degradation rates. The photocatalytic degradation of OFX and TMP with the solar photo-Fenton process followed apparent first-order kinetics. A modification of the first-order kinetic expression was proposed and has been successfully used to explain the degradation kinetics of the compounds during the solar photo-Fenton treatment. The results demonstrated the capacity of the applied advanced process to reduce the initial wastewater toxicity against the examined plant species (Sorghum saccharatum, Lepidium sativum, Sinapis alba) and the water flea Daphnia magna. The phytotoxicity of the treated samples, expressed as root growth inhibition, was higher compared to that observed on the inhibition of seed germination. Enterococci, including those resistant to OFX and TMP, were completely eliminated at the end of the treatment. The total cost of the full scale unit for the treatment of 150 m(3) day(-1) of secondary wastewater effluent was found to be 0.85 € m(-3). Copyright © 2012 Elsevier Ltd. All rights reserved.

Quantifying Fenton reaction pathways driven by self-generated H2O2 on pyrite surfaces

NASA Astrophysics Data System (ADS)

Gil-Lozano, C.; Davila, A. F.; Losa-Adams, E.; Fairén, A. G.; Gago-Duport, L.

2017-03-01

Oxidation of pyrite (FeS2) plays a significant role in the redox cycling of iron and sulfur on Earth and is the primary cause of acid mine drainage (AMD). It has been established that this process involves multi-step electron-transfer reactions between surface defects and adsorbed O2 and H2O, releasing sulfoxy species (e.g., S2O32-, SO42-) and ferrous iron (Fe2+) to the solution and also producing intermediate by-products, such as hydrogen peroxide (H2O2) and other reactive oxygen species (ROS), however, our understanding of the kinetics of these transient species is still limited. We investigated the kinetics of H2O2 formation in aqueous suspensions of FeS2 microparticles by monitoring, in real time, the H2O2 and dissolved O2 concentration under oxic and anoxic conditions using amperometric microsensors. Additional spectroscopic and structural analyses were done to track the dependencies between the process of FeS2 dissolution and the degradation of H2O2 through the Fenton reaction. Based on our experimental results, we built a kinetic model which explains the observed trend of H2O2, showing that FeS2 dissolution can act as a natural Fenton reagent, influencing the oxidation of third-party species during the long term evolution of geochemical systems, even in oxygen-limited environments.

Potential of Wood-Rotting Fungi to Attack Polystyrene Sulfonate and Its Depolymerisation by Gloeophyllum trabeum via Hydroquinone-Driven Fenton Chemistry

PubMed Central

Krueger, Martin C.; Hofmann, Ulrike; Moeder, Monika; Schlosser, Dietmar

2015-01-01

Synthetic polymers often pose environmental hazards due to low biodegradation rates and resulting accumulation. In this study, a selection of wood-rotting fungi representing different lignocellulose decay types was screened for oxidative biodegradation of the polymer polystyrene sulfonate (PSS). Brown-rot basidiomycetes showed PSS depolymerisation of up to 50 % reduction in number-average molecular mass (Mn) within 20 days. In-depth investigations with the most efficient depolymeriser, a Gloeophyllum trabeum strain, pointed at extracellular hydroquinone-driven Fenton chemistry responsible for depolymerisation. Detection of hydroxyl radicals present in the culture supernatants showed good compliance with depolymerisation over the time course of PSS degradation. 2,5-Dimethoxy-1,4-hydroquinone (2,5-DMHQ), which was detected in supernatants of active cultures via liquid chromatography and mass spectrometry, was demonstrated to drive the Fenton processes in G. trabeum cultures. Up to 80% reduction in Mn of PSS where observed when fungal cultures were additionally supplemented with 2,5-dimethoxy benzoquinone, the oxidized from of 2,5-DMHQ. Furthermore, 2,5-DMHQ could initiate the Fenton's reagent-mediated PSS depolymerisation in cell-free systems. In contrast, white-rot fungi were unable to cause substantial depolymerising effects despite the expression of lignin-modifying exo-enzymes. Detailed investigations with laccase from Trametes versicolor revealed that only in presence of certain redox mediators limited PSS depolymerisation occurred. Our results indicate that brown-rot fungi might be suitable organisms for the biodegradation of recalcitrant synthetic polymeric pollutants. PMID:26147966

Soluble organic substances extracted from compost as amendments for Fenton-like oxidation of contaminated sites.

PubMed

Zingaretti, Daniela; Lombardi, Francesco; Baciocchi, Renato

2018-04-01

The Fenton process is a well known treatment that proved to be effective for the remediation of sites contaminated by a wide range of organic pollutants. Its application to soil-water systems typically requires the addition of a stabilizer, in order to increase the H 2 O 2 lifetime and thus the radius of influence of the treatment, and a chelating agent, aimed to extract and maintain in solution the iron present in the soil. However, as the use of these compounds has been debated for their environmental impact, efforts have been placed to test new "greener" amendments. Namely, in line with the concept of circular economy introduced by the European Council, in this study we have tested the use of humic acids extracted from compost as amendment in a Fenton-like process. These substances are of potential interest as can form complexes with metal ions and act as sorbents for hydrophobic organic compounds. Fenton-like lab-scale tests with the extracted humic acids were performed on a soil-water system artificially contaminated by chlorophenol. The obtained results were compared with those achieved applying commercial humic acids or traditional amendments (i.e. KH 2 PO 4 or EDTA) used as reference. The humic acids extracted from compost allowed to achieve a H 2 O 2 lifetime close to the one obtained with traditional stabilizing agent; besides, humic acids proved also effective in removing chlorophenol, with performance close to the one achieved using a traditional chelating agent. These findings hence suggest that the use of the humic acids extracted from wastes in a Fenton-like process could allow to replace at the same time the H 2 O 2 stabilizer and the chelating agent. Copyright © 2017 Elsevier B.V. All rights reserved.

A characterization of the two-step reaction mechanism of phenol decomposition by a Fenton reaction

NASA Astrophysics Data System (ADS)

Valdés, Cristian; Alzate-Morales, Jans; Osorio, Edison; Villaseñor, Jorge; Navarro-Retamal, Carlos

2015-11-01

Phenol is one of the worst contaminants at date, and its degradation has been a crucial task over years. Here, the decomposition process of phenol, in a Fenton reaction, is described. Using scavengers, it was observed that decomposition of phenol was mainly influenced by production of hydroxyl radicals. Experimental and theoretical activation energies (Ea) for phenol oxidation intermediates were calculated. According to these Ea, phenol decomposition is a two-step reaction mechanism mediated predominantly by hydroxyl radicals, producing a decomposition yield order given as hydroquinone > catechol > resorcinol. Furthermore, traces of reaction derived acids were detected by HPLC and GS-MS.

Photocatalytic degradation of 5-nitro-1,2,4-triazol-3-one NTO in aqueous suspension of TiO2. Comparison with Fenton oxidation.

PubMed

Le Campion, L; Giannotti, C; Ouazzani, J

1999-03-01

5-nitro-1,2,4-triazol-3-one (NTO) is a powerful insensitive explosive, present in industrial waste waters. A remediation method based on photochemical decomposition and Fenton oxidation of NTO has been evaluated by monitoring the mineralization of 14C-labelled NTO. The TiO2-catalyzed photodegradation (lambda > 290 nm, TiO2 0.4 g/l, NTO 150 mg/l)) leads to the complete mineralization of NTO in 3 hours. This degradation involves a simultaneous denitrification and ring scission of NTO leading to nitrites, nitrates and carbon dioxide. No significant photo-degradation of NTO was detected in the absence of the catalyst. Long term irradiation over one week, leads to a complete degradation of concentrated NTO (5 g/l), suggesting that this method could be useful to clean-up NTO wastes. Fenton oxidation offers an efficient cost-effective method for NTO remediation. This reaction is faster that the TiO2 catalyzed photolysis and find application on the mineralization of high concentrations of NTO (15 g/l). Fenton oxidation provokes ring cleavage and subsequent elimination of the two carbon atoms of NTO as CO2. During this reaction, the nitro group is completely transformed into nitrates.

Enhanced sonochemical degradation of azure B dye by the electroFenton process.

PubMed

Martínez, Susana Silva; Uribe, Edgar Velasco

2012-01-01

The degradation of azure B dye (C15H16ClN3S; AB) has been studied by Fenton, sonolysis and sono-electroFenton processes employing ultrasound at 23 kHz and the electrogeneration of H2O2 at the reticulated vitreous carbon electrode. It was found that the dye degradation followed apparent first-order kinetics in all the degradation processes tested. The rate constant was affected by both the pH of the solution and initial concentration of Fe2+, with the highest degradation obtained at pH between 2.6 and 3. The first-order rate constant decreased in the following order: sono-electroFenton>Fenton>sonolysis. The rate constant for AB degradation by sono-electroFenton is ∼10-fold that of sonolysis and ∼2-fold the one obtained by Fenton under silent conditions. The chemical oxygen demand was abated ∼68% and ∼85% by Fenton and sono-electroFenton respectively, achieving AB concentration removal over 90% with both processes. Copyright © 2011 Elsevier B.V. All rights reserved.

Investigation of optimum conditions and costs estimation for degradation of phenol by solar photo-Fenton process

NASA Astrophysics Data System (ADS)

Gar Alalm, Mohamed; Tawfik, Ahmed; Ookawara, Shinichi

2017-03-01

In this study, solar photo-Fenton reaction using compound parabolic collectors reactor was assessed for removal of phenol from aqueous solution. The effect of irradiation time, initial concentration, initial pH, and dosage of Fenton reagent were investigated. H2O2 and aromatic intermediates (catechol, benzoquinone, and hydroquinone) were quantified during the reaction to study the pathways of the oxidation process. Complete degradation of phenol was achieved after 45 min of irradiation when the initial concentration was 100 mg/L. However, increasing the initial concentration up to 500 mg/L inhibited the degradation efficiency. The dosage of H2O2 and Fe+2 significantly affected the degradation efficiency of phenol. The observed optimum pH for the reaction was 3.1. Phenol degradation at different concentration was fitted to the pseudo-first order kinetic according to Langmuir-Hinshelwood model. Costs estimation for a large scale reactor based was performed. The total costs of the best economic condition with maximum degradation of phenol are 2.54 €/m3.

Comparison of classical fenton, nitrilotriacetic acid (NTA)-Fenton, UV-Fenton, UV photolysis of Fe-NTA, UV-NTA-Fenton, and UV-H2O2 for the degradation of cyclohexanoic acid.

PubMed

Zhang, Ying; Klamerth, Nikolaus; Chelme-Ayala, Pamela; Gamal El-Din, Mohamed

2017-05-01

The treatment of a naphthenic acid model compound, cyclohexanoic acid, with classical Fenton, UV-H 2 O 2 , UV-Fenton, nitrilotriacetic acid (NTA)-Fenton, UV-NTA-Fenton, and UV photolysis of Fe-NTA processes at pHs 3 and 8 was investigated. At 1.47 mM H 2 O 2 , 0.089 mM Fe, and 0.18 mM NTA, the UV-NTA-Fenton process at pH 3 exhibited the highest H 2 O 2 decomposition (100% in 25 min), CHA removal (100% in 12 min) with a rate constant of 0.27 ± 0.025 min -1 , and NTA degradation (100% in 6 min). Due to the formation of H 2 O 2 -Fe(III)NTA adduct, the total Fe concentration in the UV-NTA-Fenton system (0.063 mM at the end of the reaction) at pH 8 was much higher than that in the UV photolysis of Fe(III)NTA process (0.024 mM). The co-complexing effect of borate buffer helped to keep iron soluble; however, it imposed a negative influence on the CHA degradation in the UV-NTA-Fenton process (68% CHA removal in 60 min in the borate buffer compared to 92% in MilliQ water). The results demonstrated that the most efficient process for the CHA degradation under the experimental conditions was the UV-NTA-Fenton process at pH 3. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous decomplexation in blended Cu(II)/Ni(II)-EDTA systems by electro-Fenton process using iron sacrificing electrodes.

PubMed

Zhao, Zilong; Dong, Wenyi; Wang, Hongjie; Chen, Guanhan; Tang, Junyi; Wu, Yang

2018-05-15

This research explored the application of electro-Fenton (E-Fenton) technique for the simultaneous decomplexation in blended Cu(II)/Ni(II)-EDTA systems by using iron sacrificing electrodes. Standard discharge (0.3 mg L -1 for Cu and 0.1 mg L -1 for Ni in China) could be achieved after 30 min reaction under the optimum conditions (i.e. initial solution pH of 2.0, H 2 O 2 dosage of 6 mL L -1  h -1 , current density of 20 mA/cm 2 , inter-electrode distance of 2 cm, and sulfate electrolyte concentration of 2000 mg L -1 ). The distinct differences in apparent kinetic rate constants (k app ) and intermediate removal efficiencies corresponding to mere and blended systems indicated the mutual promotion effect toward the decomplexation between Cu(II) and Ni(II). Massive accumulation of Fe(Ⅲ) favored the further removal of Cu(II) and Ni(II) by metal ion substitution. Species distribution results demonstrated that the decomplexation of metal-EDTA in E-Fenton process was mainly contributed to the combination of various reactions, including Fenton reaction together with the anodic oxidation, electro-coagulation (E-coagulation) and electrodeposition. Unlike hypophosphite and citrate, the presence of chlorine ion displayed favorable effects on the removal efficiencies of Cu(II) and Ni(II) at low dosage, but facilitated the ammonia nitrogen (NH 4 + -N) removal only at high dosage. Copyright © 2018 Elsevier B.V. All rights reserved.

Degradation of anti-inflammatory drug ketoprofen by electro-oxidation: comparison of electro-Fenton and anodic oxidation processes.

PubMed

Feng, Ling; Oturan, Nihal; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A

2014-01-01

The electrochemical degradation of the nonsteroidal anti-inflammatory drug ketoprofen in tap water has been studied using electro-Fenton (EF) and anodic oxidation (AO) processes with platinium (Pt) and boron-doped diamond (BDD) anodes and carbon felt cathode. Fast degradation of the parent drug molecule and its degradation intermediates leading to complete mineralization was achieved by BDD/carbon felt, Pt/carbon felt, and AO with BDD anode. The obtained results showed that oxidative degradation rate of ketoprofen and mineralization of its aqueous solution increased by increasing applied current. Degradation kinetics fitted well to a pseudo-first-order reaction. Absolute rate constant of the oxidation of ketoprofen by electrochemically generated hydroxyl radicals was determined to be (2.8 ± 0.1) × 10(9) M(-1) s(-1) by using competition kinetic method. Several reaction intermediates such as 3-hydroxybenzoic acid, pyrogallol, catechol, benzophenone, benzoic acid, and hydroquinone were identified by high-performance liquid chromatography (HPLC) analyses. The formation, identification, and evolution of short-chain aliphatic carboxylic acids like formic, acetic, oxalic, glycolic, and glyoxylic acids were monitored with ion exclusion chromatography. Based on the identified aromatic/cyclic intermediates and carboxylic acids as end products before mineralization, a plausible mineralization pathway was proposed. The evolution of the toxicity during treatments was also monitored using Microtox method, showing a faster detoxification with higher applied current values.

Stoichio-Kinetic Modeling of Fenton Chemistry in a Meat-Mimetic Aqueous-Phase Medium.

PubMed

Oueslati, Khaled; Promeyrat, Aurélie; Gatellier, Philippe; Daudin, Jean-Dominique; Kondjoyan, Alain

2018-05-31

Fenton reaction kinetics, which involved an Fe(II)/Fe(III) oxidative redox cycle, were studied in a liquid medium that mimics meat composition. Muscle antioxidants (enzymes, peptides, and vitamins) were added one by one in the medium to determine their respective effects on the formation of superoxide and hydroxyl radicals. A stoichio-kinetic mathematical model was used to predict the formation of these radicals under different iron and H 2 O 2 concentrations and temperature conditions. The difference between experimental and predicted results was mainly due to iron reactivity, which had to be taken into account in the model, and to uncertainties on some of the rate constant values introduced in the model. This stoichio-kinetic model will be useful to predict oxidation during meat processes, providing it can be completed to take into account the presence of myoglobin in the muscle.

A new sono-electrochemical method for enhanced detoxification of hydrophilic chloroorganic pollutants in water.

PubMed

Yasman, Yakov; Bulatov, Valery; Gridin, Vladimir V; Agur, Sabina; Galil, Noah; Armon, Robert; Schechter, Israel

2004-09-01

A new method for detoxification of hydrophilic chloroorganic pollutants in effluent water was developed, using a combination of ultrasound waves, electrochemistry and Fenton's reagent. The advantages of the method are exemplified using two target compounds: the common herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) and its derivative 2,4-dichlorophenol (2,4-DCP). The high degradation power of this process is due to the large production of oxidizing hydroxyl radicals and high mass transfer due to sonication. Application of this sono-electrochemical Fenton process (SEF) treatment (at 20 kHz) with quite a small current density, accomplished almost 50% oxidation of 2,4-D solution (300 ppm, 1.2 mM) in just 60 s. Similar treatments ran for 600 s resulted in practically full degradation of the herbicide; sizable oxidation of 2,4-DCP also occurs. The main intermediate compounds produced in the SEF process were identified. Their kinetic profile was measured and a chemical reaction scheme was suggested. The efficiency of the SEF process is tentatively much higher than the reference degradation methods and the time required for full degradation is considerably shorter. The SEF process maintains high performance up to concentrations which are higher than reference methods. The optimum concentration of Fe2+ ions required for this process was found to be of about 2 mM, which is lower than that in reference techniques. These findings indicate that SEF process may be an effective method for detoxification of environmental water.

Kinetics of imidazolium-based ionic liquids degradation in aqueous solution by Fenton oxidation.

PubMed

Domínguez, Carmen M; Munoz, Macarena; Quintanilla, Asunción; de Pedro, Zahara M; Casas, Jose A

2017-10-15

In the last few years, several works dealing with Fenton oxidation of ionic liquids (ILs) have proved the capability of this technology for their degradation, achieving complete ILs removal and non-toxic effluents. Nevertheless, very little is known about the kinetics of this process, crucial for its potential application. In this work, the effect of several operating conditions, including reaction temperature (50-90 °C), catalyst load (10-50 mg L -1 Fe 3+ ), initial IL concentration (100-2000 mg L -1 ), and hydrogen peroxide dose (10-200% of the stoichiometric amount for the complete IL mineralization) on 1-butyl-3-methylimidazolium chloride ([C 4 mim]Cl) oxidation has been investigated. Under the optimum operating conditions (T = 90 °C; [Fe 3+ ] 0  = 50 mg L -1 ; [H 2 O 2 ] 0  = 100% of the stoichiometric amount), the complete removal of [C 4 mim]Cl (1000 mg L -1 ) was achieved at 1.5-min reaction time. From the experimental results, a potential kinetic model capable to describe the removal of imidazolium-based ILs by Fenton oxidation has been developed. By fitting the proposed model to the experimental data, the orders of the reaction with respect to IL initial concentration, Fe 3+ amount and H 2 O 2 dose were found to be close to 1, with an apparent activation energy of 43.3 kJ mol -1 . The model resulted in a reasonable fit within the wide range of operating conditions tested in this work.

Fenton process on single and mixture components of phenothiazine pharmaceuticals: Assessment of intermediaries, fate, and preliminary ecotoxicity.

PubMed

Wilde, Marcelo L; Schneider, Mandy; Kümmerer, Klaus

2017-04-01

Pharmaceuticals do not occur isolated in the environment but in multi-component mixtures and may exhibit antagonist, synergistic or additive behavior. Knowledge on this is still scarce. The situation is even more complicated if effluents or potable water is treated by oxidative processes or such transformations occur in the environment. Thus, determining the fate and effects of parent compounds, metabolites and transformation products (TPs) formed by transformation and degradation processes in the environment is needed. This study investigated the fate and preliminary ecotoxicity of the phenothiazine pharmaceuticals, Promazine (PRO), Promethazine (PRM), Chlorpromazine (CPR), and Thioridazine (THI) as single and as components of the resulting mixtures obtained from their treatment by Fenton process. The Fenton process was carried out at pH7 and by using 0.5-2mgL -1 of [Fe 2+ ] 0 and 1-12.5mgL -1 of [H 2 O 2 ] 0 at the fixed ratio [Fe 2+ ] 0 :[H 2 O 2 ] 0 of 1:10 (w:w). No complete mineralization was achieved. Constitutional isomers and some metabolite-like TPs formed were suggested based on their UHPLC-HRMS n data. A degradation pathway was proposed considering interconnected mechanisms such as sulfoxidation, hydroxylation, N-dealkylation, and dechlorination steps. Aerobic biodegradation tests (OECD 301 D and OECD 301 F) were applied to the parent compounds separately, to the mixture of parent compounds, and for the cocktail of TPs present after the treatment by Fenton process. The samples were not readily biodegradable. However, LC-MS analysis revealed that abiotic transformations, such hydrolysis, and autocatalytic transformations occurred. The initial ecotoxicity tested towards Vibrio fischeri as individual compounds featured a reduction in toxicity of PRM and CPR by the treatment process, whereas PRO showed an increase in acute luminescence inhibition and THI a stable luminescence inhibition. Concerning effects of the mixture components, reduction in toxicity by the Fenton process was predicted by concentration addition and independent action models. Copyright © 2017 Elsevier B.V. All rights reserved.

Heterogeneous activation of H2O2 by defect-engineered TiO(2-x) single crystals for refractory pollutants degradation: A Fenton-like mechanism.

PubMed

Zhang, Ai-Yong; Lin, Tan; He, Yuan-Yi; Mou, Yu-Xuan

2016-07-05

The heterogeneous catalyst plays a key role in Fenton-like reaction for advanced oxidation of refractory pollutants in water treatment. Titanium dioxide (TiO2) is a typical semiconductor with high industrial importance due to its earth abundance, low cost and no toxicity. In this work, it is found that TiO2 can heterogeneously activate hydrogen peroxide (H2O2, E°=1.78 eV), a common chemical oxidant, to efficiently generate highly-powerful hydroxyl radical, OH (E(0)=2.80 eV), for advanced water treatment, when its crystal shape, exposed facet and oxygen-stoichiometry are finely tuned. The defect-engineered TiO2 single crystals exposed by high-energy {001} facets exhibited an excellent Fenton-like activity and stability for degrading typical refractory organic pollutants such as methyl orange and p-nitrophenol. Its defect-centered Fenton-like superiority is mainly attributed to the crystal oxygen-vacancy, single-crystalline structure and exposed polar {001} facet. Our findings could provide new chance to utilize TiO2 for Fenton-like technology, and develop novel heterogeneous catalyst for advanced water treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of TiO2 photocatalysis, electrochemically assisted Fenton reaction and direct electrochemistry for simulation of phase I metabolism reactions of drugs.

PubMed

Ruokolainen, Miina; Gul, Turan; Permentier, Hjalmar; Sikanen, Tiina; Kostiainen, Risto; Kotiaho, Tapio

2016-02-15

The feasibility of titanium dioxide (TiO2) photocatalysis, electrochemically assisted Fenton reaction (EC-Fenton) and direct electrochemical oxidation (EC) for simulation of phase I metabolism of drugs was studied by comparing the reaction products of buspirone, promazine, testosterone and 7-ethoxycoumarin with phase I metabolites of the same compounds produced in vitro by human liver microsomes (HLM). Reaction products were analysed by UHPLC-MS. TiO2 photocatalysis simulated the in vitro phase I metabolism in HLM more comprehensively than did EC-Fenton or EC. Even though TiO2 photocatalysis, EC-Fenton and EC do not allow comprehensive prediction of phase I metabolism, all three methods produce several important metabolites without the need for demanding purification steps to remove the biological matrix. Importantly, TiO2 photocatalysis produces aliphatic and aromatic hydroxylation products where direct EC fails. Furthermore, TiO2 photocatalysis is an extremely rapid, simple and inexpensive way to generate oxidation products in a clean matrix and the reaction can be simply initiated and quenched by switching the UV lamp on/off. Copyright © 2015 Elsevier B.V. All rights reserved.

Remediation of phenanthrene from contaminated kaolinite by electroremediation-Fenton technology.

PubMed

Alcantara, T; Pazos, M; Gouveia, S; Cameselle, C; Sanroman, M A

2008-07-01

Polycyclic aromatic hydrocarbons (PAHs) cause a high environmental impact when released into the environment. The objective of this study was to evaluate the capacity to decontaminate polluted soils with phenanthrene as a model PAH using a combination of two technologies: electrokinetic remediation and Fenton process. Kaolinite was used as a model sample that was artificially polluted at the laboratory at an initial concentration of phenanthrene of 500 mg kg(-1) of dried kaolinite. The standard electrokinetic process resulted in negligible removal of phenanthrene from the kaolinite sample. Faster and more efficient degradation of this compound can be promoted by introduction of a strong oxidant into the soil such as hydroxyl radicals. For this reason, the Fenton reactions have been induced in several experiments in which H(2)O(2) (10%) was used as flushing solution, and kaolinite polluted with iron was used. When anode and cathode chambers were filled with H(2)O(2) (10%), the kaolinite pH is maintained at an acid value around 3.5 without pH control and an overall removal and destruction efficiency of phenanthrene of 99% was obtained in 14 days by applying a voltage gradient of 3 V cm(-1). Therefore, it is evident that a combined technology of electrokinetic remediation and Fenton reaction is capable of simultaneously removing and degrading of PAHs in polluted model samples with kaolinite.

Bioremediation of diesel-polluted soil using biostimulation as post-treatment after oxidation with Fenton-like reagents: assays in a pilot plant.

PubMed

Silva-Castro, Gloria Andrea; Rodelas, Belén; Perucha, Carlos; Laguna, Jaime; González-López, Jesús; Calvo, Concepción

2013-02-15

The present study focuses on the remediation of diesel-polluted soil using modified Fenton treatment coupled with inorganic NPK fertilizer ("Fenton+NPK"). Studies were carried out in a pilot plant containing 1 m(3) of sandy soil contaminated with 20,000 mg kg(-1) of diesel, placed outdoors at a temperature ranging between 5 and 10 °C. Results showed that NPK-fertilizer as post-treatment stimulated culturable degrading bacteria and enhanced dehydrogenase activity. Fenton+NPK treatment increased total petroleum hydrocarbon (TPH) removal efficacy. Natural attenuation removed 49% of TPH in the surface layer, 23% of TPH in the non-saturated layer and 4% of the TPH in the saturated layer, while the percentage removed of TPH after Fenton+NPK treatment was 58%, 57% and 32% respectively. The results from our study showed that, immediately after soil contamination, occurred a specialization and differentiation of the bacterial community, but after this initial modification, no significant changes of bacterial diversity was observed under natural attenuation conditions. In contrast, when the Fenton's reagent was applied a reduction of the bacterial biodiversity was observed. However, the post-biostimulation did enhance the degrading microbiota and stimulated their degrading biological activity. In conclusion, biostimulation, as a post-treatment step in chemical oxidation, is an effective solution to remediate hydrocarbon-polluted sites. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of toxicity and estrogenicity of the landfill-concentrated leachate during advanced oxidation treatment: chemical analyses and bioanalytical tools.

PubMed

Wang, Guifang; Lu, Gang; Zhao, Jiandi; Yin, Pinghe; Zhao, Ling

2016-08-01

Landfill-concentrated leachate from membrane separation processes is a potential pollution source for the surroundings. In this study, the toxicity and estrogenicity potentials of concentrated leachate prior to and during UV-Fenton and Fenton treatments were assessed by a combination of chemical (di (2-ethylhexyl) phthalate and dibutyl phthalate were chosen as targets) and biological (Daphnia magna, Chlorella vulgaris, and E-screen assay) analyses. Removal efficiencies of measured di (2-ethylhexyl) phthalate and dibutyl phthalate were more than 97 % after treatment with the two methods. Biological tests showed acute toxicity effects on D. magna tests in untreated concentrated leachate samples, whereas acute toxicity on C. vulgaris tests was not observed. Both treatment methods were found to be efficient in reducing acute toxicity effects on D. magna tests. The E-screen test showed concentrated leachate had significant estrogenicity, UV-Fenton and Fenton treatment, especially the former, were effective methods for reducing estrogenicity of concentrated leachate. The EEQchem (estradiol equivalent concentration) of all samples could only explain 0.218-5.31 % range of the EEQbio. These results showed that UV-Fenton reagent could be considered as a suitable method for treatment of concentrated leachate, and the importance of the application of an integrated (biological + chemical) analytical approach for a comprehensive evaluation of treatment suitability.

Light-induced catalytic transformation of ofloxacin by solar Fenton in various water matrices at a pilot plant: mineralization and characterization of major intermediate products.

PubMed

Michael, I; Hapeshi, E; Aceña, J; Perez, S; Petrović, M; Zapata, A; Barceló, D; Malato, S; Fatta-Kassinos, D

2013-09-01

This work investigated the application of a solar driven advanced oxidation process (solar Fenton), for the degradation of the antibiotic ofloxacin (OFX) in various environmental matrices at a pilot-scale. All experiments were carried out in a compound parabolic collector pilot plant in the presence of doses of H2O2 (2.5 mg L(-1)) and at an initial Fe(2+) concentration of 2 mg L(-1). The water matrices used for the solar Fenton experiments were: demineralized water (DW), simulated natural freshwater (SW), simulated effluent from municipal wastewater treatment plant (SWW) and pre-treated real effluent from municipal wastewater treatment plant (RE) to which OFX had been spiked at 10 mg L(-1). Dissolved organic carbon removal was found to be dependent on the chemical composition of the water matrix. OFX mineralization was higher in DW (78.1%) than in SW (58.3%) at 12 mg L(-1) of H2O2 consumption, implying the complexation of iron or the scavenging of hydroxyl radicals by the inorganic ions present in SW. On the other hand, the presence of dissolved organic matter (DOM) in SWW and RE, led to lower mineralization per dose of H2O2 compared to DW and SW. The major transformation products (TPs) formed during the solar Fenton treatment of OFX, were elucidated using liquid chromatography-time of flight-mass spectrometry (LC-ToF-MS). The transformation of OFX proceeded through a defluorination reaction, accompanied by some degree of piperazine and quinolone substituent transformation while a hydroxylation mechanism occurred by attack of the hydroxyl radicals generated during the process leading to the formation of TPs in all the water matrices, seven of which were tentatively identified. The results obtained from the toxicity bioassays indicated that the toxicity originates from the DOM present in RE and its oxidation products formed during the photocatalytic treatment and not from the TPs resulted from the oxidation of OFX. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Fast decolorization of azo methyl orange via heterogeneous Fenton and Fenton-like reactions using alginate-Fe2+/Fe3+ films as catalysts.

PubMed

Quadrado, Rafael F N; Fajardo, André R

2017-12-01

The efficiency of Fenton and Fenton-like processes can be seriously affected by the continuous loss of iron ions and by the formation of solid sludge. Here, alginate (Alg) films were synthesized to stabilize iron ions (Fe 2+ and Fe 3+ ) and to enhance their catalytic activities towards the decolorization of methyl orange via heterogeneous Fenton and Fenton-like processes. Iron ions were ionically bond to the Alg molecules resulting in a three-dimensional network with specific structural and morphological features according to the valence states of iron. Our results demonstrated that both Alg-Fe 2+ and Alg-Fe 3+ films show highlighted catalytic activity for the decolorization of MO and high decolorization rates. Reuse experiments demonstrated that both films could be employed in at least five consecutive decolorization processes without losing their catalytic efficiency or stability. Taken together, our findings reveal that the Alg-Fe 2+ and Alg-Fe 3+ films may be suitable low-cost catalysts in heterogeneous Fenton and Fenton-like processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantifying Fenton reaction pathways driven by self-generated H2O2 on pyrite surfaces.

PubMed

Gil-Lozano, C; Davila, A F; Losa-Adams, E; Fairén, A G; Gago-Duport, L

2017-03-06

Oxidation of pyrite (FeS 2 ) plays a significant role in the redox cycling of iron and sulfur on Earth and is the primary cause of acid mine drainage (AMD). It has been established that this process involves multi-step electron-transfer reactions between surface defects and adsorbed O 2 and H 2 O, releasing sulfoxy species (e.g., S 2 O 3 2- , SO 4 2- ) and ferrous iron (Fe 2+ ) to the solution and also producing intermediate by-products, such as hydrogen peroxide (H 2 O 2 ) and other reactive oxygen species (ROS), however, our understanding of the kinetics of these transient species is still limited. We investigated the kinetics of H 2 O 2 formation in aqueous suspensions of FeS 2 microparticles by monitoring, in real time, the H 2 O 2 and dissolved O 2 concentration under oxic and anoxic conditions using amperometric microsensors. Additional spectroscopic and structural analyses were done to track the dependencies between the process of FeS 2 dissolution and the degradation of H 2 O 2 through the Fenton reaction. Based on our experimental results, we built a kinetic model which explains the observed trend of H 2 O 2 , showing that FeS 2 dissolution can act as a natural Fenton reagent, influencing the oxidation of third-party species during the long term evolution of geochemical systems, even in oxygen-limited environments.

Reuse of recalcitrant-rich anaerobic effluent as dilution water after enhancement of biodegradability by Fenton processes.

PubMed

Arimi, Milton M; Zhang, Yongjun; Namango, Saul S; Geißen, Sven-Uwe

2016-03-01

Anaerobic digestion is used to treat effluents with a lot of organics, such as molasses distillery wastewater (MDW) which is the effluent of bioethanol production from molasses. The raw MDW requires a lot of dilution water before biodigestion, while the digested MDW has high level of recalcitrants which are problematic for its discharge. This study investigated ferric coagulation, Fenton, Fenton-like (with ferric ions as catalyst) processes and their combinations on the biodegradability of digested MDW. The Fenton and Fenton-like processes after coagulation increased the MDW biodegradability defined by (BOD5/COD) from 0.07 to (0.4-0.6) and saved 50% of H2O2 consumed in the classic Fenton process. The effluent from coagulation coupled to a Fenton-like process was used as dilution water for the raw MDW before the anaerobic digestion. The process was stable with volumetric loading of approx. 2.7 g COD/L/d. It resulted in increased overall biogas recovery and significantly decreased the demand for the dilution water. Copyright © 2015 Elsevier Ltd. All rights reserved.

Combined heterogeneous Electro-Fenton and biological process for the treatment of stabilized landfill leachate.

PubMed

Baiju, Archa; Gandhimathi, R; Ramesh, S T; Nidheesh, P V

2018-03-15

Treatment of stabilized landfill leachate is a great challenge due to its poor biodegradability. Present study made an attempt to treat this wastewater by combining electro-Fenton (E-Fenton) and biological process. E-Fenton treatment was applied prior to biological process to enhance the biodegradability of leachate, which will be beneficial for the subsequent biological process. This study also investigates the efficiency of iron molybdophosphate (FeMoPO) nanoparticles as a heterogeneous catalyst in E-Fenton process. The effects of initial pH, catalyst dosage, applied voltage and electrode spacing on Chemical Oxygen Demand (COD) removal efficiency were analyzed to determine the optimum conditions. Heterogeneous E-Fenton process gave 82% COD removal at pH 2, catalyst dosage of 50 mg/L, voltage 5 V, electrode spacing 3 cm and electrode area 25 cm 2 . Combined E-Fenton and biological treatment resulted an overall COD removal of 97%, bringing down the final COD to 192 mg/L. Copyright © 2018 Elsevier Ltd. All rights reserved.

Potential effects of rainwater-borne hydrogen peroxide on pollutants in stagnant water environments.

PubMed

Qin, Junhao; Lin, Chuxia; Cheruiyot, Patrick; Mkpanam, Sandra; Good-Mary Duma, Nelisiwe

2017-05-01

Microcosm experiments were conducted to examine the effects of rainwater-borne H 2 O 2 on inactivation of water-borne coliforms, oxidation of ammonia and nitrite, and degradation of organic pollutants in canal and urban lake water. The results show that the soluble iron in the investigated water samples was sufficiently effective for reaction with H 2 O 2 in the simulated rainwater-affected stagnant water to produce OH (Fenton reaction), which inactivated coliform bacteria even at a H 2 O 2 dose as low as 5 μM within just 1 min of contact time. Coliform inhibition could last for at least 1 h and repeated input of H 2 O 2 at a 30 min interval allowed maintenance of microbial inhibition for at least 3 h. Nitrification was also impeded by the Fenton process. The resulting inhibition of ammonia-oxidizing microbes reduced the removal rate of NH 4 + and the emission of gaseous N species. In the presence of H 2 O 2 at a dose of 20 μM, Fenton-driven chemical oxidation appeared to outplay the impediment of biodegradation caused by inhibited microbial activities in terms of removing total polycyclic aromatic hydrocarbons from the water column. The findings point to a potential research direction that may help to explain the dynamics of water-borne pollutants in ambient water environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Novel Permeable Reactive Barrier (PRB) for Simultaneous and Rapid Removal of Heavy Metal and Organic Matter - A Systematic Chemical Speciation Approach on Sustainable Technique for Pallikarani Marshland Remediation

NASA Astrophysics Data System (ADS)

Selvaraj, A.; Nambi, I. M.

2014-12-01

In this study, an innovative technique of ZVI mediated 'coupling of Fenton like oxidation of phenol and Cr(VI) reduction technique' was attempted. The hypothesis is that Fe3+ generated from Cr(VI) reduction process acts as electron acceptor and catalyst for Fenton's Phenol oxidation process. The Fe2+ formed from Fenton reactions can be reused for Cr(VI) reduction. Thus iron can be made to recycle between two reactions, changing back and forth between Fe2+ and Fe3+ forms, makes treatment sustainable.(Fig 1) This approach advances current Fenton like oxidation process by (i)single system removal of heavy metal and organic matter (ii)recycling of iron species; hence no additional iron required (iii)more contaminant removal to ZVI ratio (iv)eliminating sludge related issues. Preliminary batch studies were conducted at different modes i) concurrent removal ii) sequential removal. The sequential removal was found better for in-situ PRB applications. PRB was designed based on kinetic rate slope and half-life time, obtained from primary column study. This PRB has two segments (i)ZVI segment[Cr(VI)] (ii)iron species segment[phenol]. This makes treatment sustainable by (i) having no iron ions in outlet stream (ii)meeting hypothesis and elongates the life span of PRB. Sequential removal of contaminates were tested in pilot scale PRB(Fig 2) and its life span was calculated based on the exhaustion of filling material. Aqueous, sand and iron aliquots were collected at various segments of PRB and analyzed for precipitation and chemical speciation thoroughly (UV spectrometer, XRD, FTIR, electron microscope). Chemical speciation profile eliminates the uncertainties over in-situ PRB's long term performance. Based on the pilot scale PRB study, 'field level PRB wall construction' was suggested to remove heavy metal and organic compounds from Pallikaranai marshland(Fig 3)., which is contaminated with leachate coming from nearby Perungudi dumpsite. This research provides (i)deeper insight into the environmental friendly, accelerated, sustainable technique for combined removal of organic matter and heavy metal (ii)evaluation of the novel technique in PRB, which resulted in PRB's increased life span (iii)designing of PRB to remediate the marshland and its ecosystem, thus save the habitats related to it.

Proposal of a sequential treatment methodology for the safe reuse of oil sludge-contaminated soil.

PubMed

Mater, L; Sperb, R M; Madureira, L A S; Rosin, A P; Correa, A X R; Radetski, C M

2006-08-25

In this study sequential steps were used to treat and immobilize oil constituents of an oil sludge-contaminated soil. Initially, the contaminated soil was oxidized by a Fenton type reaction (13 wt% for H(2)O(2); 10mM for Fe(2+)). The oxidative treatment period of 80 h was carried out under three different pH conditions: 20 h at pH 6.5, 20 h at pH 4.5, and 40 h at pH 3.0. The oxidized contaminated sample (3 kg) was stabilized and solidified for 2h with clay (1 kg) and lime (2 kg). Finally, this mixture was solidified by sand (2 kg) and Portland cement (4 kg). In order to evaluate the efficiency of different processes to treat and immobilize oil contaminants of the oil sludge-contaminated soil, leachability and solubility tests were performed and extracts were analyzed according to the current Brazilian waste regulations. Results showed that the Fenton oxidative process was partially efficient in degrading the oil contaminants in the soil, since residual concentrations were found for the PAH and BTEX compounds. Leachability tests showed that clay-lime stabilization/solidification followed by Portland cement stabilization/solidification was efficient in immobilizing the recalcitrant and hazardous constituents of the contaminated soil. These two steps stabilization/solidification processes are necessary to enhance environmental protection (minimal leachability) and to render final product economically profitable. The treated waste is safe enough to be used on environmental applications, like roadbeds blocks.

Acetaminophen degradation by electro-Fenton and photoelectro-Fenton using a double cathode electrochemical cell.

PubMed

de Luna, Mark Daniel G; Veciana, Mersabel L; Su, Chia-Chi; Lu, Ming-Chun

2012-05-30

Acetaminophen is a widely used drug worldwide and is one of the most frequently detected in bodies of water making it a high priority trace pollutant. This study investigated the applicability of the electro-Fenton and photoelectro-Fenton processes using a double cathode electrochemical cell in the treatment of acetaminophen containing wastewater. The Box-Behnken design was used to determine the effects of initial Fe(2+) and H(2)O(2) concentrations and applied current density. Results showed that all parameters positively affected the degradation efficiency of acetaminophen with the initial Fe(2+) concentration being the most significant parameter for both processes. The acetaminophen removal efficiency for electro-Fenton was 98% and chemical oxygen demand (COD) removal of 43% while a 97% acetaminophen removal and 42% COD removal were observed for the photoelectro-Fenton method operated at optimum conditions. The electro-Fenton process was only able to obtain 19% total organic carbon (TOC) removal while the photoelectro-Fenton process obtained 20%. Due to negligible difference between the treatment efficiencies of the two processes, the electro-Fenton method was proven to be more economically advantageous. The models obtained from the study were applicable to a wide range of acetaminophen concentrations and can be used in scale-ups. Thirteen different types of intermediates were identified and a degradation pathway was proposed. Copyright © 2012 Elsevier B.V. All rights reserved.

Preservation of glutamic acid-iron chelate into montmorillonite to efficiently degrade Reactive Blue 19 in a Fenton system under sunlight irradiation at neutral pH

NASA Astrophysics Data System (ADS)

Huang, Zhujian; Wu, Pingxiao; Gong, Beini; Yang, Shanshan; Li, Hailing; Zhu, Ziao; Cui, Lihua

2016-05-01

To further enhance the visible light responsive property and the chemical stability of Fe/clay mineral catalysts, glutamic acid-iron chelate intercalated montmorillonite (G-Fe-Mt) was developed. The physiochemical properties of G-Fe-Mt were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), etc. The results showed that glutamic acid-iron chelates were successfully intercalated into the gallery of montmorillonite and the intercalated glutamic acid-iron chelate molecules were well preserved. The product G-Fe-Mt displayed excellent catalytic performance in heterogeneous photo-Fenton reaction under sunlight irradiation at acidic and neutral pH values. The chelation and the visible light responsiveness of glutamic acid produce a synergistic effect leading to greatly enhanced sunlight-Fenton reaction catalyzed by the heterogeneous G-Fe-Mt under neutral pH. G-Fe-Mt is a promising catalyst for advanced oxidation processes.

Sustaining 1,2-Dichloroethane Degradation in Nanoscale Zero-Valent Iron induced Fenton system by using Sequential H2O2 Addition at Natural pH

NASA Astrophysics Data System (ADS)

Phenrat, T.; Le, T. S. T.

2017-12-01

1,2-Dichloroethane (1,2-DCA) is a prevalent subsurface contaminant found in groundwater and soil around the world. Nanoscale zero-valent iron (NZVI) is a promising in situ remediation agent for chlorinated organics. Nevertheless, 1,2-DCA is recalcitrant to reductive dechlorination using NZVI. Chemical oxidation using Fenton's reaction with conventional Fe2+ is a valid option for 1,2-DCA remediation with a major technical challenge, i.e. aquifer acidification is needed to maintain Fe2+ for catalytic reaction. In this work, NZVI Fenton's process at neutral pH was applied to degrade 1,2-DCA at high concentration (2,000 mg/L) representing dissolved 1,2-DCA concentration close to non-aqueous phase liquid source zone. Instead of using acidification to maintain dissolved Fe2+ concentration, NZVI Fenton's process is self-catalytic based on oxidative dissolution of NZVI in the present of H2O2. Interfacial H+ is produced at NZVI surface to provide appropriate local pH which continuously releases Fe2+ for Fenton's reaction. Approximately, 87% of 1,2-DCA was degraded at neutral pH with the pseudo first-order rate constant of 0.98 hour-1 using 10 g/L of NZVI and 200 mM of H2O2. However, the reaction was prohibited quickly within 3 hours presumably due to the rapid depletion of H2O2. The application of sequential H2O2 addition provided a better approach to prevent rapid inhibition via controlling the H2O2 concentration in the system to be sufficient but not excess, thus resulting in the higher degradation efficiency (the pseudo first-order rate constant of 0.49 hour-1 and 99 % degradation in 8 hours). Using NZVI with sequential H2O2 addition was also successful in degrading 1,2-DCA sorbed on to soil, yielding 99% removal of 1,2-DCA within 16 hours at the rate constant of 0.23 hour-1, around two times slower than in the system without soil presumably due to rate-limited 1,2-DCA desorption from soil. Mechanistic understanding of how sequential addition of H2O2, in comparison to the simultaneous H2O2 addition, can sustain oxidative degradation of 1,2-DCA was also proposed in addition to the investigation of NZVI reusability in three consecutive 1, 2-DCA degradation cycles.

Enhanced Oxidative and Adsorptive Removal of Diclofenac in Heterogeneous Fenton-like Reaction with Sulfide Modified Nanoscale Zerovalent Iron.

PubMed

Su, Yiming; Jassby, David; Song, Shikun; Zhou, Xuefei; Zhao, Hongying; Filip, Jan; Petala, Eleni; Zhang, Yalei

2018-06-05

Sulfidation of nanoscale zerovalent iron (nZVI) has shown some fundamental improvements on reactivity and selectivity toward pollutants in dissolved-oxygen (DO)-stimulated Fenton-like reaction systems (DO/S-nZVI system). However, the pristine microstructure of sulfide-modified nanoscale zerovalent iron (S-nZVI) remains uncovered. In addition, the relationship between pollutant removal and the oxidation of the S-nZVI is largely unknown. The present study confirms that sulfidation not only imparts sulfide and sulfate groups onto the surface of the nanoparticle (both on the oxide shell and on flake-like structures) but also introduces sulfur into the Fe(0) core region. Sulfidation greatly inhibits the four-electron transfer pathway between Fe(0) and oxygen but facilitates the electron transfer from Fe(0) to surface-bound Fe(III) and consecutive single-electron transfer for the generation of H 2 O 2 and hydroxyl radical. In the DO/S-nZVI system, slight sulfidation (S/Fe molar ratio = 0.1) is able to nearly double the oxidative removal efficacy of diclofenac (DCF) (from 17.8 to 34.2%), whereas moderate degree of sulfidation (S/Fe molar ratio = 0.3) significantly enhances both oxidation and adsorption of DCF. Furthermore, on the basis of the oxidation model of S-nZVI, the DCF removal process can be divided into two steps, which are well modeled by parabolic and logarithmic law separately. This study bridges the knowledge gap between pollutant removal and the oxidation process of chemically modified iron-based nanomaterials.

Mechanism and toxicity research of benzalkonium chloride oxidation in aqueous solution by H2O2/Fe(2+) process.

PubMed

Zhang, Qian; Xia, Yu-Feng; Hong, Jun-Ming

2016-09-01

As widely used disinfectants, the pollution caused by benzalkonium chloride (BAC) has attracted a lot of attention in recent years. Since it is not suitable for biodegradation, BAC was degraded firstly by Fenton advanced oxidation technologies (AOTs) in this research to enhance the biodegradability of the pollutions. The result revealed that the optimal molar ratio of H2O2/Fe(2+) for BAC degradation was 10:1, and the COD removal rate was 32 %. To clarify the pathway of degradation, the technique of GC-MS was implemented herein to identify intermediates and the toxicity of those BAC intermediates were also novelty tested through microbial fuel cells (MFC). The findings indicated that ten transformation products including benzyl dimethyl amine and dodecane were formed during the H2O2/Fe(2+) processes, which means the degradation pathway of BAC was initiated both on the hydrophobic (alkyl chain) and hydrophilic (benzyl and ammonium moiety) region of the surfactant. The toxicity of BAC before and after treated by Fenton process was monitored through MFC system. The electricity generation was improved 337 % after BAC was treated by H2O2/Fe(2+) oxidation processes which indicated that the toxicity of those intermediates were much lower than BAC. The mechanism and toxicity research in this paper could provide the in-depth understanding to the pathway of BAC degradation and proved the possibility of AOTs for the pretreatment of a biodegradation process.

The detrimental influence of bacteria (E. coli, Shigella and Salmonella) on the degradation of organic compounds (and vice versa) in TiO2 photocatalysis and near-neutral photo-Fenton processes under simulated solar light.

PubMed

Moncayo-Lasso, Alejandro; Mora-Arismendi, Luis Enrique; Rengifo-Herrera, Julián Andrés; Sanabria, Janeth; Benítez, Norberto; Pulgarin, César

2012-05-01

TiO2 photocatalytic and near-neutral photo-Fenton processes were tested under simulated solar light to degrade two models of natural organic matter - resorcinol (R) (which should interact strongly with TiO2 surfaces) and hydroquinone (H) - separately or in the presence of bacteria. Under similar oxidative conditions, inactivation of Escherichia coli, Shigella sonnei and Salmonella typhimurium was carried out in the absence and in the presence of 10 mg L(-1) of R and H. The 100% abatement of R and H by using a TiO2 photocatalytic process in the absence of bacteria was observed in 90 min for R and in 120 min for H, while in the presence of microorganisms abatement was only of 55% and 35% for R and H, respectively. Photo-Fenton reagent at pH 5.0 completely removed R and H in 40 min, whereas in the presence of microorganisms their degradation was of 60% to 80%. On the other hand, 2 h of TiO2 photocatalytic process inactivated S. typhimurium and E. coli cells in three and six orders of magnitude, respectively, while S. sonnei was completely inactivated in 10 min. In the presence of R or H, the bacterial inactivation via TiO2 photocatalysis was significantly decreased. With photo-Fenton reagent at pH 5 all the microorganisms tested were completely inactivated in 40 min of simulated solar light irradiation in the absence of organics. When R and H were present, bacterial photo-Fenton inactivation was less affected. The obtained results suggest that in both TiO2 and iron photo-assisted processes, there is competition between organic substances and bacteria simultaneously present for generated reactive oxygen species (ROS). This competition is most important in heterogeneous systems, mainly when there are strong organic-TiO2 surface interactions, as in the resorcinol case, suggesting that bacteria-TiO2 interactions could play a key role in photocatalytic cell inactivation processes.

PREDICTING FENTON-DRIVEN DEGRADATION USING CONTAMINANT ANALOG

EPA Science Inventory

The reaction of hydrogen peroxide (H2O2) and Fe(II) (Fenton's reaction) generates hydroxyl radicals (OH) that can be used to oxidize contaminants in soils and aquifers. In such environments, insufficient iron, reactions involving H2O2 that do not yield OH, and OH reactions with ...

USE OF FENTON'S REAGENT AS DISINFECTING AGENT

EPA Science Inventory

This project was conducted as an EPA in-house research, assisted by the on-site contractor, US Infrastructure, Inc. (USI) located in Edison, NJ. The Fenton's reagent (e.g., H2O2, ferrous iron Fe(aq)+2) is an alternative method of chemical oxidation. Hydroxyl radicals (OH ), gen...

Protective effects of Merlot red wine extract and its major polyphenols in PC12 cells under oxidative stress conditions.

PubMed

Martín, Sara; González-Burgos, Elena; Carretero, M Emilia; Gómez-Serranillos, M Pilar

2013-01-01

The potential effect of the extracts from free-run and pressed Merlot red wine has been evaluated in PC12 cells under oxidative stress situation. Comparing both vinification process, pressed Merlot red wine extract possessed higher neuroprotective activity than the free run wine, possibly attributed to the major content in all global polyphenolic families. High performance liquid chromatography determination of individual polyphenols showed that the major compounds found in Merlot red wine extract were quercetin, catechin, epicatechin, tyrosol, gallic acid, and procyanidins. Pretreatments with these polyphenolic compounds (0.25 mM and 0.1 mM, 24 h) significantly increased cell viability of H(2)O(2) and Fenton reaction treated cells. Moreover, these polyphenols attenuated ROS production and decreased the Redox Index of glutathione (RI = GSSG/GSH + GSSG) in cells treated only with Fenton reaction. Furthermore, some polyphenols induced antioxidant enzymes activity and protein expression. Quercetin was the most active. These results support the beneficial effects of red wine extracts and some of its polyphenols under oxidative stress conditions. This research provides evidences of the preventive properties of wine extracts and its major polyphenols under oxidative stress conditions. © 2012 Institute of Food Technologists®

Ultrasound-assisted advanced oxidation processes for water decontamination.

PubMed

Ince, Nilsun H

2018-01-01

The study reflects a part of my experience in sonochemistry and ultrasound-assisted advanced oxidation processes (AOPs) acquired during the last fifteen years with my research team. The data discussed were selected from studies with azo dyes, endocrine disrupting compounds and analgesic/anti-inflammatory pharmaceuticals, which are all classified as "hazardous" or "emerging" contaminants. The research focused on their treatability by ultrasound (US) and AOPs with emphasis on the mineralization of organic carbon. Some of the highlights as pointed out in the manuscript are: i) ultrasound is capable of partially or completely oxidizing the above contaminant groups if the operating conditions are properly selected and optimized, but incapable of mineralizing them; ii) the mechanism of degradation in homogeneous solutions is OH-mediated oxidation in the bulk solution or at the bubble-liquid interface, depending on the molecular properties of the contaminant, the applied frequency and pH; iii) US-assisted AOPs such as ozonation, UV/peroxide, Fenton and UV/Fenton are substantially more effective than ultrasound alone, particularly for the mineralization process; iv) catalytic processes involving TiO 2 , alumina and zero-valent iron and assisted by ultrasound are promising options not only for the destruction of the parent compounds, but also for the mineralization of their oxidation byproducts. The degradation reactions in heterogeneous solutions take place mostly at the catalyst surface despite the high-water solubility of the compounds; v) sonolytic modification of the above catalysts to reduce their particle size (to nano-levels) or to decorate the surface with metallic nanoparticles increases the catalytic activity under sonolysis, photolysis and both, and improves the stability of the catalyst. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid degradation of p-arsanilic acid with simultaneous arsenic removal from aqueous solution using Fenton process.

PubMed

Xie, Xiande; Hu, Yuanan; Cheng, Hefa

2016-02-01

Although banned in some developed countries, p-arsanilic acid (p-ASA) is still used widely as a feed additive for swine production in many countries. With little uptake and transformation in animal bodies, nearly all the p-ASA administered to animals is excreted chemically unchanged in animal wastes, which can subsequently release the more toxic inorganic arsenic species upon degradation in the environment. For safe disposal of the animal wastes laden with p-ASA, we proposed a method of leaching the highly water-soluble p-ASA out of the manure first, followed by treatment of the leachate using the Fenton process to achieve fast oxidation of p-ASA and removal of the inorganic arsenic species released (predominantly arsenate) from solution simultaneously. The effects of solution pH, dosages of H2O2 and Fe(2+), and the presence of dissolved organic matter (DOM) on the treatment efficiency were systematically investigated. Under the optimum treatment conditions (0.53 mmol L(-1) Fe(2+), 2.12 mmol L(-1) H2O2, and initial pH of 3.0), p-ASA (10 mg-As L(-1)) could be completely oxidized to As(V) within 30 min in pure water and 4 natural water samples, and at the final pH of 4.0, the residual arsenic levels in solution phase were as low as 1.1 and 20.1-43.4 μg L(-1) in the two types of water matrixes, respectively. The presence of humic acid significantly retarded the oxidation of p-ASA by scavenging HO, and inhibited the As(V) removal through competitive adsorption on ferric hydroxide. Due to the high contents of DOM in the swine manure leachate samples (TOC at ∼500 mg L(-1)), much higher dosages of Fe(2+) (10.0 mmol L(-1)) and H2O2 (40.0 mmol L(-1)) and a longer treatment time (120 min) were required to achieve near complete oxidation of p-ASA (98.0%), while maintaining the levels of residual arsenic in the solution at <70.0 μg L(-1). The degradation pathway of p-ASA in the Fenton process was proposed based on the major degradation products detected. Together, the results demonstrate that the Fenton process is promising as an efficient, robust, and low-cost treatment method for controlling the risk of p-ASA in the animal wastes generated at factory farms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of some herbicides on the biomass activity in biological treatment plants and biodegradability enhancement by a photo-Fenton process.

PubMed

Benzaquén, T B; Benzzo, M T; Isla, M A; Alfano, O M

2013-01-01

In recent years, the use of agrochemicals has increased because they are essential for profitable agricultural production. Herbicides are heavily demanded compounds and among these, the most marketed are 2,4-D, atrazine and acetochlor. They have characteristics that can cause problems to humans and the environment. Therefore, it is necessary to design systems that can reduce these compounds to harmless molecules. This work aims at evaluating the possibility of incorporating these herbicides into degradable effluents in a biological treatment system, without reducing its efficiency. For this purpose, studies of organic matter degradability in the presence of these agrochemicals were performed. A synthetic effluent based on glucose and mineral salts was inoculated with microorganisms. Glucose consumption and biomass concentration were assessed. Subsequently, preliminary studies were performed to test the viability of degradation of the most harmful compound with an advanced oxidation process (AOP). The results showed that the incorporation of these herbicides into degradable effluents in a biological treatment system has a negative impact on microorganisms. Therefore, the application of an AOP, such as the Fenton or photo-Fenton processes, prior to a biological treatment was found to degrade these substances to simpler and less toxic molecules.

Application of excitation and emission matrix fluorescence (EEM) and UV-vis absorption to monitor the characteristics of Alizarin Red S (ARS) during electro-Fenton degradation process.

PubMed

Lai, Bo; Zhou, Yuexi; Wang, Juling; Yang, Zhishan; Chen, Zhiqiang

2013-11-01

Oxidative degradation of Alizarin Red S (ARS) in aqueous solutions by using electro-Fenton was studied. At first, effect of operating parameters such as current density, aeration rate and initial pH on the degradation of ARS were studied by using UV-vis spectrum, respectively. Then, under the optimal operating conditions (current density: 10.0mAcm(-2), aeration rate: 1000mLmin(-1), initial pH: 2.8), the identification of degradation products of ARS was carried out by using GC-MS and HPLC, meanwhile its degradation pathway was proposed according to the intermediates. Considering the location, intensity and intensity ratio of fluorescence center peak of the ARS in aqueous solution, a convenient and quick monitoring method by using excitation-emission matrix fluorescence spectrum technology was developed to monitor the degradation degree of ARS through electro-Fenton process. Furthermore, it is suggested that the developed method would be promising for the quick analysis and evaluation of the degradation degree of the pollutants with π-conjugated system. Copyright © 2013 Elsevier Ltd. All rights reserved.

Removal of artificial sweetener aspartame from aqueous media by electrochemical advanced oxidation processes.

PubMed

Lin, Heng; Oturan, Nihal; Wu, Jie; Sharma, Virender K; Zhang, Hui; Oturan, Mehmet A

2017-01-01

The degradation and mineralization of aspartame (ASP) in aqueous solution were investigated, for the first time, by electrochemical advanced oxidation processes (EAOPs) in which hydroxyl radicals were formed concomitantly in the bulk from Fenton reaction via in situ electrogenerated Fenton's reagent and at the anode surface from the water oxidation. Experiments were performed in an undivided cylindrical glass cell with a carbon-felt cathode and a Pt or boron-doped diamond (BDD) anode. The effect of Fe 2+ concentration and applied current on the degradation and mineralization kinetics of ASP was evaluated. The absolute rate constant for the reaction between ASP and OH was determined as (5.23 ± 0.02) × 10 9  M -1  s -1 by using the competition kinetic method. Almost complete mineralization of ASP was achieved with BDD anode at 200 mA constant current electrolysis. The formation and generation of the formed carboxylic acids (as ultimate end products before complete mineralization) and released inorganic ion were monitored by ion-exclusion high performance liquid chromatography (HPLC) and ion chromatography techniques, respectively. The global toxicity of the treated ASP solution during treatment was assessed by the Microtox ® method using V. fischeri bacteria luminescence inhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of Fenton's oxidation of herbicide dicamba in water using response surface methodology

NASA Astrophysics Data System (ADS)

Sangami, Sanjeev; Manu, Basavaraju

2017-12-01

In this study Fenton's oxidation of dicamba in aqueous medium was investigated by using the response surface methodology. The influence of H2O2/COD ( A), H2O2/Fe2+ ( B), pH ( C) and reaction time ( D) as independent variables were studied on two responses (COD and dicamba removal efficiency). The dosage of H2O2 (5.35-17.4 mM) and Fe2+ (0.09-2.13 mM) were varied and optimum percentage removal of dicamba of 84.01% with H2O2 and Fe2+ dosage of 11.38 and 0.33 mM respectively. The whole oxidation process was monitored by high performance liquid chromatography (HPLC) along with liquid chromatography/mass spectrometry (LC/MS). It was found that 82% of dicamba was mineralized to oxalic acid, chloride ion, CO2 and H2O, which was confirmed with COD removal of 81.53%. The regression analysis was performed, in which standard deviation (<4%), coefficient of variation (<8), F value (Fisher's Test) (>2.74), coefficient of correlation ( R 2 = R_{adj}2) and adequate precision (>12) were in good agreement with model values. Finally, the treatment process was validated by performing the additional experiments.

Pretreatment of furfural industrial wastewater by Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate processes: a comparative study.

PubMed

Yang, C W; Wang, D; Tang, Q

2014-01-01

The Fenton, electro-Fenton and Fe(II)-activated peroxydisulfate (PDS) processes have been applied for the treatment of actual furfural industrial wastewater in this paper. Through the comparative study of the three processes, a suitable pretreatment technology for actual furfural wastewater treatment was obtained, and the mechanism and dynamics process of this technology is discussed. The experimental results show that Fenton technology has a good and stable effect without adjusting pH of furfural wastewater. At optimal conditions, which were 40 mmol/L H₂O₂ initial concentration and 10 mmol/L Fe²⁺ initial concentration, the chemical oxygen demand (COD) removal rate can reach 81.2% after 90 min reaction at 80 °C temperature. The PDS process also has a good performance. The COD removal rate could attain 80.3% when Na₂S₂O₈ initial concentration was 4.2 mmol/L, Fe²⁺ initial concentration was 0.1 mol/L, the temperature remained at 70 °C, and pH value remained at 2.0. The electro-Fenton process was not competent to deal with the high-temperature furfural industrial wastewater and only 10.2% COD was degraded at 80 °C temperature in the optimal conditions (2.25 mA/cm² current density, 4 mg/L Na₂SO₄, 0.3 m³/h aeration rate). For the Fenton, electro-Fenton and PDS processes in pretreatment of furfural wastewater, their kinetic processes follow the pseudo first order kinetics law. The pretreatment pathways of furfural wastewater degradation are also investigated in this study. The results show that furfural and furan formic acid in furfural wastewater were preferentially degraded by Fenton technology. Furfural can be degraded into low-toxicity or nontoxic compounds by Fenton pretreatment technology, which could make furfural wastewater harmless and even reusable.

Response surface modeling for optimization heterocatalytic Fenton oxidation of persistence organic pollution in high total dissolved solid containing wastewater.

PubMed

Sekaran, G; Karthikeyan, S; Boopathy, R; Maharaja, P; Gupta, V K; Anandan, C

2014-01-01

The rice-husk-based mesoporous activated carbon (MAC) used in this study was precarbonized and activated using phosphoric acid. N2 adsorption/desorption isotherm, X-ray powder diffraction, electron spin resonance, X-ray photoelectron spectroscopy and scanning electron microscopy, transmission electron microscopy, (29)Si-NMR spectroscopy, and diffuse reflectance spectroscopy were used to characterize the MAC. The tannery wastewater carrying high total dissolved solids (TDS) discharged from leather industry lacks biodegradability despite the presence of dissolved protein. This paper demonstrates the application of free electron-rich MAC as heterogeneous catalyst along with Fenton reagent for the oxidation of persistence organic compounds in high TDS wastewater. The heterogeneous Fenton oxidation of the pretreated wastewater at optimum pH (3.5), H2O2 (4 mmol/L), FeSO4[Symbol: see text]7H2O (0.2 mmol/L), and time (4 h) removed chemical oxygen demand, biochemical oxygen demand, total organic carbon and dissolved protein by 86, 91, 83, and 90%, respectively.

Evaluating the photo-catalytic application of Fenton's reagent augmented with TiO(2) and ZnO for the mineralization of an oil-water emulsion.

PubMed

Tony, Maha A; Zhao, Y Q; Purcell, P J; El-Sherbiny, M F

2009-04-01

In the present study, homogenous (photo-Fenton) and heterogeneous photo-assisted systems (Fenton/TiO(2)/UV, Fenton/ZnO/UV and Fenton/TiO(2)/UV/Air) were investigated for the treatment of a diesel-oil wastewater emulsion. The augmentation of the photo-Fenton process by heterogeneous TiO(2) increased the reaction rate, in terms of COD reduction efficiency from 61% to 71%. Furthermore, the COD removal efficiency was increased to 84% when air was bubbled through the reactants. However, if the Fenton/TiO(2) /UV/Air process is to be utilized as a treatment for this wastewater, the separation of the TiO(2) from the treated effluent would need further consideration.

Decolorization of reactive dyes in solar pond reactors: Perspectives and challenges for the textile industry.

PubMed

Chavaco, L C; Arcos, C A; Prato-Garcia, D

2017-08-01

In the past three decades, Fenton and photo-Fenton processes have been the subject of a large number of research studies aimed at developing a low-cost and robust alternative to treat complex wastewater. Aspects such as installation and operating costs and technical complexity of reactors have limited the commercial applications of Fenton processes. In this study, we evaluated the potential of solar pond reactors to carry out degradation of the dye reactive orange 16 (RO16). Decolorization (D = 99 ± 0.6%), chemical oxygen demand reduction (COD = 55 ± 2%), total organic carbon removal (TOC = 28 ± 0.5%), and biocompatibilization can be accomplished using 15% peroxide (0.6 mg H 2 O 2 /mg RO16), which is theoretically required to mineralize the dye. Under dark conditions, decolorization and aromatic removal were scarcely affected (2%), whereas COD and TOC removal were reduced to 37% and 16%, respectively. The application of multivariable analysis and the use of low-cost reactors may lead to a reduction in annual treatment costs of colored effluents to 0.76 (US/m 3 ). Furthermore, the treatment capacity can be increased from 0.6 m 3 wastewater/m 2 reactor surface to 1.7 m 3 wastewater/m 2 reactor surface without compromising process efficiency or the biodegradability (BOD 5 /COD ratio) of the effluent. Dyeing auxiliaries, mainly NaCl, appreciably reduced the decolorization performance in Fenton (13 ± 0.4%) and photo-Fenton (83 ± 0.5%) processes due to the formation of iron-chloride complexes and less powerful oxidants. To reduce the impact of auxiliary agents on process performance and treatment capacity, the Fe 2+ concentration should be increased from 5 mg/L to 15 mg/L. The results seem promising; however, additional studies at pilot and semi-industrial scales should be conducted to demonstrate the potential of low-cost reactors to carry out colored wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of Fenton and ozone-based advanced oxidation processes as mature landfill leachate pre-treatments.

PubMed

Cortez, Susana; Teixeira, Pilar; Oliveira, Rosário; Mota, Manuel

2011-03-01

Fenton treatment (Fe(2+)/H(2)O(2)) and different ozone-based Advanced Oxidation Processes (AOPs) (O(3), O(3)/OH(-) and O(3)/H(2)O(2)) were evaluated as pre-treatment of a mature landfill leachate, in order to improve the biodegradability of its recalcitrant organic matter for subsequent biological treatment. With a two-fold diluted leachate, at optimised experimental conditions (initial pH 3, H(2)O(2) to Fe(2+) molar ratio of 3, Fe(2+) dosage of 4 mmol L(-1), and reaction time of 40 min) Fenton treatment removed about 46% of chemical oxygen demand (COD) and increased the five-day biochemical oxygen demand (BOD(5)) to COD ratio (BOD(5)/COD) from 0.01 to 0.15. The highest removal efficiency and biodegradability was achieved by ozone at higher pH values, solely or combined with H(2)O(2). These results confirm the enhanced production of hydroxyl radical under such conditions. After the application for 60 min of ozone at 5.6 g O(3)h(-1), initial pH 7, and 400 mg L(-1) of hydrogen peroxide, COD removal efficiency was 72% and BOD(5)/COD increased from 0.01 to 0.24. An estimation of the operating costs of the AOPs processes investigated revealed that Fe(2+)/H(2)O(2) was the most economical system (8.2 € m(-3)g(-1) of COD removed) to treat the landfill leachate. This economic study, however, should be treated with caution since it does not consider the initial investment, prices at plant scale, maintenance and labour costs. Copyright © 2010 Elsevier Ltd. All rights reserved.

Degradation of alachlor and pyrimethanil by combined photo-Fenton and biological oxidation.

PubMed

Ballesteros Martín, M M; Sánchez Pérez, J A; García Sánchez, J L; Montes de Oca, L; Casas López, J L; Oller, I; Malato Rodríguez, S

2008-06-30

Biodegradability of aqueous solutions of the herbicide alachlor and the fungicide pyrimethanil, partly treated by photo-Fenton, and the effect of photoreaction intermediates on growth and DOC removal kinetics of the bacteria Pseudomonas putida CECT 324 are demonstrated. Toxicity of 30-120 mg L(-1) alachlor and pyrimethanil has been assayed in P. putida. The biodegradability of photocatalytic intermediates found at different photo-treatment times was evaluated for each pesticide. At a selected time during batch-mode phototreatment, larger-scale biodegradation kinetics were analysed in a 12 L bubble column bioreactor. Both alachlor and pyrimethanil are non-toxic for P. putida CECT 324 at the test concentrations, but they are not biodegradable. A approximately 100 min photo-Fenton pre-treatment was enough to enhance biodegradability, the biological oxidation response being dependent on the pesticide tested. The different alachlor and pyrimethanil respiration and carbon uptake rates in pre-treated solutions are related to change in the growth kinetics of P. putida. Reproducible results have shown that P. putida could be a suitable microorganism for determining photo-Fenton pre-treatment time.

Enhancement of Fenton and photo-Fenton processes at initial circumneutral pH for the degradation of the β-blocker metoprolol.

PubMed

Romero, V; Acevedo, S; Marco, P; Giménez, J; Esplugas, S

2016-01-01

The need for acidification in the Fenton and photo-Fenton process is often outlined as one of its major drawbacks, thus in this work the acidification of the Metoprolol (MET) is avoided by the addition of resorcinol (RES), which is used to simulate model organic matter. The experiments were carried out at natural pH (6.2) with different Fe(2+) (1, 2.5, 5, and 10 mg/L) and H2O2 (25, 50, 125 and 150 mg/L) concentrations. The performance of MET and RES degradation was assessed along the reaction time. Working with the highest concentrations (5 and 10 mg/L of ferrous iron and 125 and 150 mg/L of H2O2) more than 90% of MET and RES removals were reached within 50 and 20 min of treatment, respectively, by Fenton process. However a low mineralization was achieved in both cases, likely, due to by-products accumulation. Regarding to photo-Fenton process, within 3 min with the highest iron and hydrogen peroxide concentrations, a complete MET degradation was obtained and 95% of RES conversion was achieved. Parameters such Total Organic Carbon, Chemical Oxygen Demand, and AOS were measured. Intermediates were identified and MET degradation path was proposed in the presence of resorcinol. Finally, a comparison between Fenton and photo-Fenton processes at acid pH and at initial circumneutral pH was discussed. The positive effect of RES on Fenton and photo-Fenton systems has been confirmed, allowing the work at circumneutral pH. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of AOPs for the removal of natural organic matter: performance and economic assessment.

PubMed

Murray, C A; Parsons, S A

2004-01-01

Control of disinfection by-products during water treatment is primarily achieved by reducing the levels of organic precursor species prior to chlorination. Many waters contain natural organic matter at levels up to 15 mg L(-1); therefore it is necessary to have a range of control methods to support conventional coagulation. Advanced oxidation processes are such processes and in this paper the Fenton and photo-Fenton processes along with photocatalysis are assessed for their NOM removal potential. The performance of each process is shown to be dependent on pH and chemical dose as well as the initial NOM concentration. Under optimum conditions the processes achieved greater than 90% removal of DOC and UV254 absorbance. This removal led to the THMFP of the source water being reduced from 140 to below 10 microg L(-1), well below UK and US standards. An economic assessment of the processes revealed that currently such processes are not economic. With advances in technology and tightening of water quality standards these processes should become economically feasible options.

Comparison of different advanced degradation processes for the removal of the pharmaceutical compounds diclofenac and carbamazepine from liquid solutions.

PubMed

Capodaglio, Andrea G; Bojanowska-Czajka, Anna; Trojanowicz, Marek

2018-04-18

Carbamazepine and diclofenac are two examples of drugs with widespread geographical and environmental media proliferation that are poorly removed by traditional wastewater treatment processes. Advanced oxidation processes (AOPs) have been proposed as alternative methods to remove these compounds in solution. AOPs are based on a wide class of powerful technologies, including UV radiation, ozone, hydrogen peroxide, Fenton process, catalytic wet peroxide oxidation, heterogeneous photocatalysis, electrochemical oxidation and their combinations, sonolysis, and microwaves applicable to both water and wastewater. Moreover, processes rely on the production of oxidizing radicals (•OH and others) in a solution to decompose present pollutants. Water radiolysis-based processes, which are an alternative to the former, involve the use of concentrated energy (beams of accelerated electrons or γ-rays) to split water molecules, generating strong oxidants and reductants (radicals) at the same time. In this paper, the degradation of carbamazepine and diclofenac by means of all these processes is discussed and compared. Energy and byproduct generation issues are also addressed.

Simultaneous E. coli inactivation and NOM degradation in river water via photo-Fenton process at natural pH in solar CPC reactor. A new way for enhancing solar disinfection of natural water.

PubMed

Moncayo-Lasso, Alejandro; Sanabria, Janeth; Pulgarin, César; Benítez, Norberto

2009-09-01

Bacteria inactivation and natural organic matter oxidation in river water was simultaneously conducted via photo-Fenton reaction at "natural" pH ( approximately 6.5) containing 0.6 mg L(-1) of Fe(3+) and 10 mg L(-1) of H(2)O(2). The experiments were carried out by using a solar compound parabolic collector on river water previously filtered by a slow sand filtration system and voluntarily spiked with Escherichia coli. Fifty five percent of 5.3 mg L(-1) of dissolved organic carbon was mineralized whereas total disinfection was observed without re-growth after 24h in the dark.

On-surface Fenton and Fenton-like reactions appraised by paper spray ionization mass spectrometry.

PubMed

Resende, S F; Oliveira, B S; Augusti, R

2018-06-21

On-surface degradation of sildenafil (an adequate substrate as it contains assorted functional groups in its structure) promoted by the Fenton (Fe 2+ / H 2 O 2 ) and Fenton-like (M n+ / H 2 O 2 ; M n+ = Fe 3+ , Co 2+ , Cu 2+ , Mn 2+ ) systems was investigated by using paper spray ionization mass spectrometry (PS-MS). The performance of each system was compared by measuring the ratio between the relative intensities of the ions of m/z 475 (protonated sildenafil) and m/z 235 (protonated lidocaine, used as a convenient internal standard and added to the paper just before the PS-MS analyzes). The results indicated the following order in the rates of such reactions: Fe 2+ /H 2 O 2 > H 2 O 2 > Cu 2+ /H 2 O 2 > M n+ / H 2 O 2 (M n+ = Fe 3+ , Co 2+ , Mn 2+ ) ~ M n+ (M n+ = Fe 2+ , Fe 3+ , Co 2+ , Cu 2+ , Mn 2 . The superior capability of Fe 2+ /H 2 O 2 in causing the degradation of sildenafil indicates that Fe 2+ efficiently decomposes H 2 O 2 to yield hydroxyl radicals, quite reactive species that cause the substrate oxidation. The results also indicate that H 2 O 2 can spontaneously decompose likely to yield hydroxyl radicals, although in a much smaller extension than the Fenton system. This effect, however, is strongly inhibited by the presence of the other cations, i. e. Fe 3+ , Co 2+ , Cu 2+ and Mn 2+ . A unique oxidation by-product was detected in the reaction between Fe 2+ /H 2 O 2 with sildenafil and a possible structure for it was proposed based on the MS/MS data. The on-surface reaction of other substrates (trimethoprim and tamoxifen) with the Fenton system was also investigated. In conclusion, PS-MS shown to be a convenient platform to promptly monitor on-surface oxidation reactions. This article is protected by copyright. All rights reserved.

Homogeneous photocatalytic oxidation of UV filter para-aminobenzoic acid in aqueous solutions.

PubMed

Tsoumachidou, Sophia; Lambropoulou, Dimitra; Poulios, Ioannis

2017-01-01

The presence of personal care product (PCP) residues in the aquatic environment is an emerging issue due to their uncontrolled release through graywater; for this reason, efforts are being made to develop methods to inactivate or eliminate this class of substances in the environment. In this work, homogeneous photocatalysis has been applied for the degradation of UV filter para-aminobenzoic acid (PABA), which exists in several types of PCPs, in order to identify the optimum degradation conditions. The oxidation of PABA by photo-Fenton and oxalate-induced photo-Fenton (ferrioxalate) processes was investigated, and the effect of various operating variables has been assessed, i.e., Fe 3+ (0.0035-0.014 g L -1 ), H 2 O 2 (0.025-0.2 g L -1 ), T (280-323 K), and type of radiation (UV-A, visible). Furthermore, experiments under optimal conditions have been performed in order to evaluate the transformation pathways and phytotoxicity of the treated PABA solution.

Investigation of Oxidation Methods for Waste Soy Sauce Treatment.

PubMed

Jang, Hyun-Hee; Seo, Gyu-Tae; Jeong, Dae-Woon

2017-10-07

To obtain a suitable oxidation method for removing the color and lowering the chemical oxygen demand (COD) of waste soy sauce, Fenton (Fe 2+ ), Fenton-like (Fe 3+ ), and ozone (O₃) oxidation methods are used as the target reactions. In experimental conditions for Fenton oxidation, the dose of Fe 2+ and Fe 3+ was varied between 100 mg/L and 300 mg/L. The dose of hydrogen peroxide for the reaction was injected from 100-1000 mg/L. For ozone oxidation, the pH was increased from 3 to 14 and the O₃-containing gas was supplied continuously for 30 min through a gas diffuser at the bottom of the reactor at different applied O₃ doses (10-90 mg/L). We subjected it to a simple 1:20 dilution with deionized water to identify the comparison result in detail. O 3 oxidation shows the highest efficiencies of color removal (81.1%) and COD lowering (64.9%) among the three oxidation methods. This is mainly due to the fact that it has a relatively large amount of hydroxyl radical, resulting in the degradation of organics. Thus, O₃ oxidation could be a promising method for removing the color and lowering the COD of waste soy sauce. The critical parameters (pH and applied O₃ dose) were varied systematically to optimize O₃ oxidation. It was found that the optimum pH and applied O₃ dose are 11.0 mg/L and 50.0 mg/L, respectively (color removal = 34.2%, COD removal = 27.4%).

Heterogeneous Fenton-like discoloration of methyl orange using Fe3O4/MWCNTs as catalyst: kinetics and Fenton-like mechanism

NASA Astrophysics Data System (ADS)

Xu, Huan-Yan; Wang, Yuan; Shi, Tian-Nuo; Zhao, Hang; Tan, Qu; Zhao, Bo-Chao; He, Xiu-Lan; Qi, Shu-Yan

2018-03-01

The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe3O4/MWCNTs-H2O2 Fenton-like reaction for MO degradation. The results indicated that this reaction followed the first-order kinetic model. The relationship of reaction rate constant and temperature followed the Arrhenius equation. The activation energy and frequency factor of this system were calculated as 8.2 kJ·mol-1 and 2.72 s-1, respectively. The quantifications of Fe ions dissolution and •OH radicals generation confirmed that the homogeneous and heterogeneous catalyses were involved in Fe3O4/MWCNTs-H2O2 Fenton-like reaction. The reaction rate constant was closely related with Fe ions dissolution and •OH radicals generation. Fe3O4/MWCNTs nanocomposites had typical ferromagnetic property and could be easily separated from solution by an external magnet after being used. Furthermore, Fe3O4/MWCNTs nanocomposites exhibited good stability and recyclability. Finally, the Fenton-like mechanisms on homogeneous and heterogeneous catalyses were described.

Kinetic Modeling of a Heterogeneous Fenton Oxidative Treatment of Petroleum Refining Wastewater

PubMed Central

Basheer Hasan, Diya'uddeen; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

2014-01-01

The mineralisation kinetics of petroleum refinery effluent (PRE) by Fenton oxidation were evaluated. Within the ambit of the experimental data generated, first-order kinetic model (FKM), generalised lumped kinetic model (GLKM), and generalized kinetic model (GKM) were tested. The obtained apparent kinetic rate constants for the initial oxidation step (k 2′), their final oxidation step (k 1′), and the direct conversion to endproducts step (k 3′) were 10.12, 3.78, and 0.24 min−1 for GKM; 0.98, 0.98, and nil min−1 for GLKM; and nil, nil, and >0.005 min−1 for FKM. The findings showed that GKM is superior in estimating the mineralization kinetics. PMID:24592152

Characterization of dissolved organic matter in landfill leachate during the combined treatment process of air stripping, Fenton, SBR and coagulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, ZhiPing, E-mail: liulqs@163.com; Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020; Wu, WenHui

Highlights: • DOM fractions spectra analysis during the whole treatment process. • Efficient method was achieved to remove organic matters in landfill leachate. • Molecular weight distribution and fractions were discussed. - Abstract: A combined treatment process of air stripping + Fenton + sequencing batch reactor (SBR)+ coagulation was performed to remove the pollutants in landfill leachate. Molecular weight (MW) distribution and fractions of dissolved organic matter (DOM) were discussed to study the characteristics. The experiment showed that the removal rate of chemical oxygen demand (COD), five day biological oxygen demand (BOD{sub 5}) and ammonia nitrogen (NH{sub 3}−N) by themore » combined process were 92.8%, 87.8% and 98.0%, respectively. Humic acid (HA) and fulvic acid (FA) were the main fractions in raw leachate with 81.8% of the total COD concentration, while hydrophilic organic matter (HyI) was the dominant fraction in the final effluent of the combined process with 63.5% of the total COD concentration. After the combined treatment process, the removal rate of DOM and fractions HA, FA, HyI were 91.9%, 97.1%, 95.8% and 71.7%, respectively. Organic matters of MW < 2 k and MW > 100 k were removed with 90.5% and 97.9% COD concentration after the treatment. The ultraviolet–visible spectra (UV–vis), Fourier transform infrared spectra (FTIR) and three-dimensional excitation-emission matrices spectra (EEMs) indicated that benzene materials and phenol compounds were preferentially removed in air stripping. High MW matters, aromatic rings, conjugated moieties and some functional groups were mainly removed by Fenton. While small MW fractions, carboxylic acids, alcohols and protein-like materials were preferentially biodegraded via SBR. Fulvic-like and humic-like materials were mainly destroyed via Fenton oxidation and coagulation.« less

Use of Fenton reagent combined with humic acids for the removal of PFOA from contaminated water.

PubMed

Santos, Aurora; Rodríguez, Sergio; Pardo, Fernando; Romero, Arturo

2016-09-01

Perfluorinated compounds (PFCs) are receiving significant attention due to its global distribution, high persistence, and bioaccumulation properties. Among them, perfluorooctanoic acid (PFOA) is one of the most commonly found in the environment. The strong bond C-F in PFOA is extremely difficult to degrade, therefore advanced oxidation processes (AOPs) at room temperature and pressure are not able to oxidize them, as was noticed here using Fenton like reagent (FR) or persulfate (PS) at 25°C. On the contrary, by using persulfate activated by heat (100mM and T=70°C) a complete defluorination of PFOA 0.1mM was noticed after 18h, with a sequential degradation mechanism of losing one CF2 unit from PFOA and its intermediates (perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPA) and perfluorobutanoic acid (PFBA)). Since this thermal treatment is not usually desirable from an economical point of view, alternative process has been tested. For this scope, a hybrid process is proposed in this work, by adding humic acid, HA, (600mgL(-1)) and FR, (165mM in H2O2 and 3mM in Fe(3+)) to the 0.1mM PFOA solution. It was found that the HA was oxidized by FR. PFOA was entrapped quantitatively and irreversibly during HA oxidation, resulting PFOA non-available to the aqueous phase. Oxidized HA with PFOA entrapped precipitates. Both, the leftover Fe(III) acting as a coagulant and neutral pH enhance the separation of this solid phase. The precipitation noticed by adding HA to the PFOA solution in absence of FR was negligible. Copyright © 2015 Elsevier B.V. All rights reserved.

Fenton-like Degradation of MTBE: Effects of Iron Counter Anion and Radical Scavengers

EPA Science Inventory

Fenton-driven oxidation of Methyl tert-butyl ether (MTBE) (0.11-0.16 mM) in batch reactors containing ferric iron (5 mM), hydrogen peroxide (H2O2) (6 mM) (pH=3) was performed to investigate MTBE transformation mechanisms. Independent variables included the form of iron (Fe) (Fe2(...

Catalytic Wastewater Treatment Using Pillared Clays

NASA Astrophysics Data System (ADS)

Perathoner, Siglinda; Centi, Gabriele

After introduction on the use of solid catalysts in wastewater treatment technologies, particularly advanced oxidation processes (AOPs), this review discussed the use of pillared clay (PILC) materials in three applications: (i) wet air catalytic oxidation (WACO), (ii) wet hydrogen peroxide catalytic oxidation (WHPCO) on Cu-PILC and Fe-PILC, and (iii) behavior of Ti-PILC and Fe-PILC in the photocatalytic or photo-Fenton conversion of pollutants. Literature data are critically analyzed to evidence the main direction to further investigate, in particularly with reference to the possible practical application of these technologies to treat industrial, municipal, or agro-food production wastewater.

Removal of organic pollutants from produced water using Fenton oxidation

NASA Astrophysics Data System (ADS)

Afzal, Talia; Hasnain Isa, Mohamed; Mustafa, Muhammad Raza ul

2018-03-01

Produced water (PW) is the largest stream of wastewater from oil and gas exploration. It is highly polluted and requires proper treatment before disposal. The main objective of this study was to investigate the effectiveness of Fenton oxidation in degradation of organic matter in PW. The role of operating factors viz., H2O2 concentration (0.12 × 10-3 moles/L to 3 moles/L), [H2O2]/[Fe2+] molar ratio (2 to 75), and reaction time (30 to 200 minutes), on COD removal was determined through a series of batch experiments conducted in acidic environment at room temperature. The experiments were conducted with 500 mL PW samples in 1L glass beakers covered on the outside with aluminum foil to protect them from sunlight. Pre-decided amounts of ferrous sulfate heptahydrate (FeSO4.7H2O) and hydrogen peroxide (H2O2) were added to initiate the Fenton reaction. An increase in COD removal was observed with increase in reaction time and [H2O2]/[Fe2+] molar ratio. COD removal also increased with H2O2 concentration up to 0.01 moles/L; further increase in H2O2 concentration decreased the COD removal efficiency. Over 90% COD removal was achieved under optimum reaction conditions. The study indicates that Fenton oxidation is effective for remediation of PW in terms of organic matter removal.

Effect of iron salt type and dosing mode on Fenton-based pretreatment of rice straw for enzymatic hydrolysis.

PubMed

Gan, Yu-Yan; Zhou, Si-Li; Dai, Xiao; Wu, Han; Xiong, Zi-Yao; Qin, Yuan-Hang; Ma, Jiayu; Yang, Li; Wu, Zai-Kun; Wang, Tie-Lin; Wang, Wei-Guo; Wang, Cun-Wen

2018-06-15

Fenton-based processes with four different iron salts in two different dosing modes were used to pretreat rice straw (RS) samples to increase their enzymatic digestibility. The composition analysis shows that the RS sample pretreated by the dosing mode of iron salt adding into H 2 O 2 has a much lower hemicellulose content than that pretreated by the dosing mode of H 2 O 2 adding into iron salt, and the RS sample pretreated by the chloride salt-based Fenton process has a much lower lignin content and a slightly lower hemicellulose content than that pretreated by the sulphate salt-based Fenton process. The higher concentration of reducing sugar observed on the RS sample with lower lignin and hemicellulose contents justifies that the Fenton-based process could enhance the enzymic hydrolysis of RS by removing hemicellulose and lignin and increasing its accessibility to cellulase. FeCl 3 ·6H 2 O adding into H 2 O 2 is the most efficient Fenton-based process for RS pretreatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Combined ultrasound with Fenton treatment for the degradation of carcinogenic polycyclic aromatic hydrocarbons in textile dying sludge.

PubMed

Zhang, Jian-Hao; Zou, Hai-Yuan; Ning, Xun-An; Lin, Mei-Qing; Chen, Chang-Min; An, Tai-Cheng; Sun, Jian

2017-03-22

To develop an effective method to remove the toxic and carcinogenic polycyclic aromatic hydrocarbons (CPAHs) from textile dyeing sludge, five CPAHs were selected to investigate the degradation efficiencies using ultrasound combined with Fenton process (US/Fenton). The results showed that the synergistic effect of the US/Fenton process on the degradation of CPAHs in textile dyeing sludge was significant with the synergy degree of 30.4. During the US/Fenton process, low ultrasonic density showed significant advantage in degrading the CPAHs in textile dyeing sludge. Key reaction parameters on CPAHs degradation were optimized by the central composite design as followed: H 2 O 2 concentration of 152 mmol/L, ultrasonic density of 408 W/L, pH value of 3.7, the molar ratio of H 2 O 2 to Fe 2+ of 1.3 and reaction time of 43 min. Under the optimal conditions of the US/Fenton process, the degradation efficiencies of five CPAHs were obtained as 81.23% (benzo[a]pyrene) to 84.98% (benz[a]anthracene), and the benzo[a]pyrene equivalent (BaP eq ) concentrations of five CPAHs declined by 81.22-85.19%, which indicated the high potency of US/Fenton process for removing toxic CPAHs from textile dyeing sludge.

Practical applications of the Fenton reaction to the removal of chlorinated aromatic pollutants. Oxidative degradation of 2,4-dichlorophenol.

PubMed

Detomaso, Antonia; Lopez, Antonio; Lovecchio, Giangiuseppe; Mascolo, Giuseppe; Curci, Ruggero

2003-01-01

Chlorophenols (CPs) constitute a group of organic pollutants that are introduced into the environment as a result of several man-made activities, such as uncontrolled use of pesticides and herbicides, and as byproducts in the paper pulp bleaching. Promising removal technologies of chlorinated aromatics consist in the application of advanced oxidation processes (AOPs) that can provide an almost total degradation of a variety of contaminants. Among these, wide application find Fenton systems based on generation of reactive species having a high oxidizing power, such as hydroxyl radical HO*. Our objective was that of determining the overall degradation efficiency of the model compound 2,4-dichlorophenol (DCP) by thermal Fenton-type oxidation systems with a view toward defining in more details relevant process parameters, the effect of reaction temperature and of co-catalyst Cu2+. Reaction conditions were similar to those generally adopted as optimal in many practical applications, i.e. pollutant/Fe2+ (as FeSO4) ratio ca. 20, Fe2+/Cu2+ (co-catalyst) 2:1, pH adjusted and controlled at pH 3, and H2O2 in excess (up to four-fold over the stoichiometric amount required for complete mineralization). The results demonstrate that it is advantageous to carry out the reaction at a temperature markedly higher (70 degrees C) than ambient. The stepwise addition of H2O2 in aliquots yields an efficient transformation, while allowing a convenient control of the reaction exothermicity. Under these conditions, the essentially complete removal of the initial DCP is accomplished using just one equiv of H2O2 during 15 min; excess H2O2 (5 equivalents) yields extensive substrate mineralization. Also relevant, at 70 degrees C dechlorination of the initial DCP (and of derived reaction intermediates) is remarkably extensive (3-5% residual TOX), already with the addition of 1 equiv of H2O2. At the end of the reaction, IC and IC-MS analyses of the solution reveal that only low-molecular weight carboxylic acid (acetic, formic, oxalic, malonic, tartaric, etc.) contribute to the residual TOC. The whole of the results herein point to the advantage of performing the process at temperatures substantially higher than ambient (70 degrees C). Under the conditions adopted, almost complete degradation of the initial toxic compound can be achieved using hydrogen peroxide in fair excess (e.g., 3.5 equiv H2O2). In applying practical Fenton-type degradation systems to heavily polluted wastes, either for the pre-treatment of waters with a high COD value prior to biodegradation or for complete mineralization of pollutants, the set up of appropriate reaction conditions appears to be a key factor. Also, it is desirable to keep the concentration of iron salts within the lower limits in order to minimize the production and disposal of iron oxide sludges.

Remediation of Cu metal-induced accelerated Fenton reaction by potato peels bio-sorbent.

PubMed

Azmat, Rafia; Moin, Sumeira; Saleem, Ailyan

2016-12-01

This article has allied exposure to Ecological Particulate Matter (EPM) and its remediation using potato peel surface (PPC) bio-sorbent on two important edible crops Spinacia oleracea and Luffa acutangula. Fenton reaction acceleration was one of the major stress oxidation reactions as a consequence of iron and copper toxicity, which involve in the formation of hydroxyl radical (OH) through EPM. Results showed that the oxidative stress encouraged by Cu in both species that recruits the degradation of photosynthetic pigments, initiating decline in growth, reduced leaf area and degrade proteins. The plants were cultivated in natural environmental condition in three pots with three replicates like (a) control, (b) Cu treated and (c) treated water. Oxidative stress initiated by metal activity in Cu accumulated plant (b) were controlled, through bio-sorption of metal from contaminated water using PPC; arranged at laboratory scale. The acceleration of Fenton reaction was verified in terms of OH radical generation. These radicals were tested in aqueous extract of leaves of three types of plants via benzoic acid. The benzoic acid acts as a scavenger of OH radical due to which the decarboxylation of benzoic acid cured. Observation on (b) showed more rapid decarboxylation as compared to other plants which showed that Cu activity was much higher in (b) as compared to (a) and (c). The rapid decarboxylation of benzoic acid and lower chlorophyll contents in (b) suggest that Fenton reaction system was much enhanced by Cu-O and Fe-O chemistry that was successfully controlled by PPC which results in restoring the metabolic pathway and nullifying oxidative stress in (c).

Fenton process-affected transformation of roxarsone in paddy rice soils: Effects on plant growth and arsenic accumulation in rice grain.

PubMed

Qin, Junhao; Li, Huashou; Lin, Chuxia

2016-08-01

Batch and greenhouse experiments were conducted to examine the effects of Fenton process on transformation of roxarsone in soils and its resulting impacts on the growth of and As uptake by a rice plant cultivar. The results show that addition of Fenton reagent markedly accelerated the degradation of roxarsone and produced arsenite, which was otherwise absent in the soil without added Fenton reagent. Methylation of arsenate was also enhanced by Fenton process in the earlier part of the experiment due to abundant supply of arsenate from Roxarsone degradation. Overall, addition of Fenton reagent resulted in the predominant presence of arsenate in the soils. Fenton process significantly improved the growth of rice in the maturity stage of the first crop, The concentration of methylated As species in the rice plant tissues among the different growth stages was highly variable. Addition of Fenton reagent into the soils led to reduced uptake of soil-borne As by the rice plants and this had a significant effect on reducing the accumulation of As in rice grains. The findings have implications for understanding As biogeochemistry in paddy rice field receiving rainwater-borne H2O2 and for development of mitigation strategies to reduce accumulation of As in rice grains. Copyright © 2016 Elsevier Inc. All rights reserved.

Photocatalytic Iron Oxide Micro-Swimmers for Environmental Remediation

NASA Astrophysics Data System (ADS)

Richard, Cynthia; Simmchen, Juliane; Eychmüller, Alexander

2018-05-01

Harvesting energy from photochemical reactions has long been studied as an efficient means of renewable energy, a topic that is increasingly gaining importance also for motion at the microscale. Iron oxide has been a material of interest in recent studies. Thus, in this work different synthesis methods and encapsulation techniques were used to try and optimize the photo-catalytic properties of iron oxide colloids. Photodegradation experiments were carried out following the encapsulation of the nanoparticles and the Fenton effect was also verified. The end goal would be to use the photochemical degradation of peroxide to propel an array of swimmers in a controlled manner while utilizing the Fenton effect for the degradation of dyes or waste in wastewater remediation.

Decolourization of methyl orange using iron- immobilize MKSF in UV assisted Fenton-like reaction

NASA Astrophysics Data System (ADS)

Abdullah, N. H.; Zubir, N. A.; Hassan, H.

2017-09-01

In this work, montmorillonite KSF clay was used to immobilize iron species as a potential heterogeneous UV assisted Fenton-like reaction. Iron-immobilized MKSF (Fe-MKSF) was synthesized via hydrothermal method in an autoclave. Fe-MKSF was tested on methyl orange (MO) removal by adsorption (5%) and hydrogen peroxide (H2O2) activation (63%) and these prominent margins proved Fe-MKSF performance was attributed by UV assisted Fenton-like reaction. Fe-MKSF show superior performance with 63% color removal within 180 mins reaction in comparison to iron oxide and pristine MKSF. The Fe-MKSF increased in the surface area from 91.1 to 101.9 m2/g and pore volume from 0.13 to 0.45 cm3/g compared to pristine MKSF. The SEM images of Fe-MKSF show iron aggregates indicating successful immobilizing process and the elemental weight percent of iron which increase from 6.12% to 55.38% in Fe-MKSF. These findings prove Fe-MKSF as a promising alternative catalyst in dye contaminated wastewater treatment.

Decolorization of C.I. Acid Blue 9 solution by UV/Nano-TiO(2), Fenton, Fenton-like, electro-Fenton and electrocoagulation processes: a comparative study.

PubMed

Khataee, A R; Vatanpour, V; Amani Ghadim, A R

2009-01-30

This study makes a comparison between UV/Nano-TiO(2), Fenton, Fenton-like, electro-Fenton (EF) and electrocoagulation (EC) treatment methods to investigate the removal of C.I. Acid Blue 9 (AB9), which was chosen as the model organic contaminant. Results indicated that the decolorization efficiency was in order of Fenton>EC>UV/Nano-TiO(2)>Fenton-like>EF. Desired concentrations of Fe(2+) and H(2)O(2) for the abatement of AB9 in the Fenton-based processes were found to be 10(-4)M and 2 x 10(-3) M, respectively. In the case of UV/Nano-TiO(2) process, we have studied the influence of the basic photocatalytic parameters such as the irradiation time, pH of the solution and amount of TiO(2) nanoparticles on the photocatalytic decolorization efficiency of AB9. Accordingly, it could be stated that the complete removal of color, after selecting desired operational parameters could be achieved in a relatively short time, about 25 min. Our results also revealed that the most effective decomposition of AB9 was observed with 150 mg/l of TiO(2) nanoparticles in acidic condition. The effect of operational parameters including current density, initial pH and time of electrolysis were studied in electrocoagulation process. The results indicated that for a solution of 20 mg/l AB9, almost 98% color were removed, when the pH was about 6, the time of electrolysis was 8 min and the current density was approximately 25 A/m(2) in electrocoagulation process.

Effect of pre-heating on the chemical oxidation efficiency: implications for the PAH availability measurement in contaminated soils.

PubMed

Biache, Coralie; Lorgeoux, Catherine; Andriatsihoarana, Sitraka; Colombano, Stéfan; Faure, Pierre

2015-04-09

Three chemical oxidation treatments (KMnO4, H2O2 and Fenton-like) were applied on three PAH-contaminated soils presenting different properties to determine the potential use of these treatments to evaluate the available PAH fraction. In order to increase the available fraction, a pre-heating (100 °C under N2 for one week) was also applied on the samples prior oxidant addition. PAH and extractable organic matter contents were determined before and after treatment applications. KMnO4 was efficient to degrade PAHs in all the soil samples and the pre-heating slightly improved its efficiency. H2O2 and Fenton-like treatments presented low efficiency to degrade PAH in the soil presenting poor PAH availability, however, the PAH degradation rates were improved with the pre-heating. Consequently H2O2-based treatments (including Fenton-like) are highly sensitive to contaminant availability and seem to be valid methods to estimate the available PAH fraction in contaminated soils. Copyright © 2014 Elsevier B.V. All rights reserved.

Removal of binary dyes mixtures with opposite and similar charges by adsorption, coagulation/flocculation and catalytic oxidation in the presence of CeO2/H2O2 Fenton-like system.

PubMed

Issa Hamoud, Houeida; Finqueneisel, Gisèle; Azambre, Bruno

2017-06-15

In this study, the removal of binary mixtures of dyes with similar (Orange II/Acid Green 25) or opposite charges (Orange II/Malachite Green) was investigated either by simple adsorption on ceria or by the heterogeneous Fenton reaction in presence of H 2 O 2 . First, the CeO 2 nanocatalyst with high specific surface area (269 m 2 /g) and small crystal size (5 nm) was characterized using XRD, Raman spectroscopy and N 2 physisorption at 77 K. The adsorption of single dyes was studied either from thermodynamic and kinetic viewpoints. It is shown that the adsorption of dyes on ceria surface is highly pH-dependent and followed a pseudo-second order kinetic model. Adsorption isotherms fit well the Langmuir model with a complete monolayer coverage and higher affinity towards Orange II at pH 3, compared to other dyes. For the (Orange II/Acid Green 25) mixture, both the amounts of dyes adsorbed on ceria surface and discoloration rates measured from Fenton experiments were decreased by comparison with single dyes. This is due to the adsorption competition existing onto the same surface Ce x+ sites and the reaction competition with hydroxyl radicals, respectively. The behavior of the (Orange II/Malachite Green) mixture is markedly different. Dyes with opposite charges undergo paired adsorption on ceria as well as homogeneous and heterogeneous coagulation/flocculation processes, but can also be removed by heterogeneous Fenton process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of peat on Fenton oxidation.

PubMed

Huling, S G; Arnold, R G; Sierka, R A; Miller, M R

2001-05-01

A diagnostic probe was used to estimate the activity of Fenton-derived hydroxyl radicals (.OH), reaction kinetics, and oxidation efficiency in batch suspensions comprised of silica sand, crushed goethite (alpha-FeOOH) ore, peat, and H2O2 (0.13 mM). A simple method of kinetic analysis is presented and used to estimate the rate of .OH production (POH) and scavenging term (ks), which were used to establish the influence of organic matter (Pahokee peat) in Fenton systems. POH was greater in the peat-amended systems than in the unamended control, and ks was approximately the same. Any increase in scavenging of .OH that resulted from the addition of peat was insignificant in comparison to radical scavenging by reaction with H2O2. Also, treatment efficiency, defined as the ratio of probe conversion to H2O2 consumption over the same period was greater in the peat-amended system. Results suggest that .OH production is enhanced in the presence of peat by one or more peat-dependent mechanisms. Fe concentration and availability in the peat, reduction of Fe(III) to Fe(II) by the organic matter, and reduction of organic-complexed Fe(III) to Fe(II) are discussed in the context of the Fenton mechanism.

Investigation of Oxidation Methods for Waste Soy Sauce Treatment

PubMed Central

Jang, Hyun-Hee; Seo, Gyu-Tae

2017-01-01

To obtain a suitable oxidation method for removing the color and lowering the chemical oxygen demand (COD) of waste soy sauce, Fenton (Fe2+), Fenton-like (Fe3+), and ozone (O3) oxidation methods are used as the target reactions. In experimental conditions for Fenton oxidation, the dose of Fe2+ and Fe3+ was varied between 100 mg/L and 300 mg/L. The dose of hydrogen peroxide for the reaction was injected from 100–1000 mg/L. For ozone oxidation, the pH was increased from 3 to 14 and the O3-containing gas was supplied continuously for 30 min through a gas diffuser at the bottom of the reactor at different applied O3 doses (10–90 mg/L). We subjected it to a simple 1:20 dilution with deionized water to identify the comparison result in detail. O3 oxidation shows the highest efficiencies of color removal (81.1%) and COD lowering (64.9%) among the three oxidation methods. This is mainly due to the fact that it has a relatively large amount of hydroxyl radical, resulting in the degradation of organics. Thus, O3 oxidation could be a promising method for removing the color and lowering the COD of waste soy sauce. The critical parameters (pH and applied O3 dose) were varied systematically to optimize O3 oxidation. It was found that the optimum pH and applied O3 dose are 11.0 mg /L and 50.0 mg /L, respectively (color removal = 34.2%, COD removal = 27.4%). PMID:28991163

Advanced Treatment of Pesticide-Containing Wastewater Using Fenton Reagent Enhanced by Microwave Electrodeless Ultraviolet

PubMed Central

Cheng, Gong; Lin, Jing; Lu, Jian; Zhao, Xi; Cai, Zhengqing; Fu, Jie

2015-01-01

The photo-Fenton reaction is a promising method to treat organic contaminants in water. In this paper, a Fenton reagent enhanced by microwave electrodeless ultraviolet (MWEUV/Fenton) method was proposed for advanced treatment of nonbiodegradable organic substance in pesticide-containing biotreated wastewater. MWEUV lamp was found to be more effective for chemical oxygen demand (COD) removal than commercial mercury lamps in the Fenton process. The pseudo-first order kinetic model can well describe COD removal from pesticide-containing wastewater by MWEUV/Fenton, and the apparent rate constant (k) was 0.0125 min−1. The optimal conditions for MWEUV/Fenton process were determined as initial pH of 5, Fe2+ dosage of 0.8 mmol/L, and H2O2 dosage of 100 mmol/L. Under the optimal conditions, the reaction exhibited high mineralization degrees of organics, where COD and dissolved organic carbon (DOC) concentration decreased from 183.2 mg/L to 36.9 mg/L and 43.5 mg/L to 27.8 mg/L, respectively. Three main pesticides in the wastewater, as Dimethoate, Triazophos, and Malathion, were completely removed by the MWEUV/Fenton process within 120 min. The high degree of pesticides decomposition and mineralization was proved by the detected inorganic anions. PMID:26347877

Toxicity assessment of tannery effluent treated by an optimized photo-Fenton process.

PubMed

Borba, Fernando Henrique; Módenes, Aparecido Nivaldo; Espinoza-Quiñones, Fernando Rodolfo; Manenti, Diego Ricieri; Bergamasco, Rosangela; Mora, Nora Diaz

2013-01-01

In this work, an optimized photo-Fenton process was applied to remove pollutants from tannery industrial effluent (TIE) with its final toxicity level being assessed by a lettuce-seed-based bioassay test. A full 33 factorial design was applied for the optimization of long-term photo-Fenton experiments. The oPtimum conditions of the photo-Fenton process were attained at concentration values of 0.3 g Fe(2+) L(-1) and 20 g H2O2 L(-1) and pH3, for 120 min UV irradiation time. Reactor operating parameter (ROP) effects on the removal of chemical oxygen demand, colour, turbidity, total suspended solids and total volatile solids were evaluated, suggesting that a broad range of ROP values are also suitable to give results very near to those of the photo-Fenton experiments under optimal conditions. Based on the low calculated median lethal dose (LD50) values from a lettuce-seed-based bioassay test, we suggest that recalcitrant substances are present in treated TIE samples. A possible cause of the high toxicity level could partly be attributed to the nitrate concentration, which was not completely abated by the photo-Fenton process. Apart from this, the photo-Fenton process can be used as a part of an industrial effluent treatment system in order to abate high organic pollutant loads.

Magnetic porous Fe3O4/carbon octahedra derived from iron-based metal-organic framework as heterogeneous Fenton-like catalyst

NASA Astrophysics Data System (ADS)

Li, Wenhui; Wu, Xiaofeng; Li, Shuangde; Tang, Wenxiang; Chen, Yunfa

2018-04-01

The synthesis of effective and recyclable Fenton-like catalyst is still a key factor for advanced oxidation processes. Herein, magnetic porous Fe3O4/carbon octahedra were constructed by a two-step controlled calcination of iron-based metal organic framework. The porous octahedra were assembled by interpenetrated Fe3O4 nanoparticles coated with graphitic carbon layer, offering abundant mesoporous channels for the solid-liquid contact. Moreover, the oxygen-containing functional groups on the surface of graphitic carbon endow the catalysts with hydrophilic nature and well-dispersion into water. The porous Fe3O4/carbon octahedra show efficiently heterogeneous Fenton-like reactions for decomposing the organic dye methylene blue (MB) with the help of H2O2, and nearly 100% removal efficiency within 60 min. Furthermore, the magnetic catalyst retains the activity after ten cycles and can be easily separated by external magnetic field, indicating the long-term catalytic durability and recyclability. The good Fenton-like catalytic performance of the as-synthesized Fe3O4/carbon octahedra is ascribed to the unique mesoporous structure derived from MOF-framework, as well as the sacrificial role and stabilizing effect of graphitic carbon layer. This work provides a facile strategy for the controllable synthesis of integrated porous octahedral structure with graphitic carbon layer, and thereby the catalyst holds significant potential for wastewater treatment.

Removal of pharmaceuticals from MWTP effluent by nanofiltration and solar photo-Fenton using two different iron complexes at neutral pH.

PubMed

Miralles-Cuevas, S; Oller, I; Pérez, J A Sánchez; Malato, S

2014-11-01

In recent years, membrane technologies (nanofiltration (NF)/reverse osmosis (RO)) have received much attention for micropollutant separation from Municipal Wastewater Treatment Plant (MWTP) effluents. Practically all micropollutants are retained in the concentrate stream, which must be treated. Advanced Oxidation Processes (AOPs) have been demonstrated to be a good option for the removal of microcontaminants from water systems. However, these processes are expensive, and therefore, are usually combined with other techniques (such as membrane systems) in an attempt at cost reduction. One of the main costs in solar photo-Fenton comes from reagent consumption, mainly hydrogen peroxide and chemicals for pH adjustment. Thus, in this study, solar photo-Fenton was used to treat a real MWTP effluent with low initial iron (less than 0.2 mM) and hydrogen peroxide (less than 2 mM) concentrations. In order to work at neutral pH, iron complexing agents (EDDS and citrate) were used in the two cases studied: direct treatment of the MWTP effluent and treatment of the concentrate stream generated by NF. The degradation of five pharmaceuticals (carbamazepine, flumequine, ibuprofen, ofloxacin and sulfamethoxazole) spiked in the effluent at low initial concentrations (μg L(-1)) was monitored as the main variable in the pilot-plant-scale photo-Fenton experiments. In both effluents, pharmaceuticals were efficiently removed (>90%), requiring low accumulated solar energy (2 kJUV L(-1), key parameter in scaling up the CPC photoreactor) and low iron and hydrogen peroxide concentrations (reagent costs, 0.1 and 1.5 mM, respectively). NF provided a clean effluent, and the concentrate was positively treated by solar photo-Fenton with no significant differences between the direct MWTP effluent and NF concentrate treatments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lignocellulosic Biomass Transformations via Greener Oxidative Pretreatment Processes: Access to Energy and Value-Added Chemicals

PubMed Central

Den, Walter; Sharma, Virender K.; Lee, Mengshan; Nadadur, Govind; Varma, Rajender S.

2018-01-01

Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the problems associated with the conventional processes. The mechanisms of reaction pathways, selectivity and efficiency of end-products obtained using greener processes such as ozonolysis, photocatalysis, oxidative catalysis, electrochemical oxidation, and Fenton or Fenton-like reactions, as applied to depolymerization of lignocellulosic biomass are summarized with deliberation on future prospects of biorefineries with greener pretreatment processes in the context of the life cycle assessment. PMID:29755972

Lignocellulosic Biomass Transformations via Greener Oxidative Pretreatment Processes: Access to Energy and Value-Added Chemicals.

PubMed

Den, Walter; Sharma, Virender K; Lee, Mengshan; Nadadur, Govind; Varma, Rajender S

2018-01-01

Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the problems associated with the conventional processes. The mechanisms of reaction pathways, selectivity and efficiency of end-products obtained using greener processes such as ozonolysis, photocatalysis, oxidative catalysis, electrochemical oxidation, and Fenton or Fenton-like reactions, as applied to depolymerization of lignocellulosic biomass are summarized with deliberation on future prospects of biorefineries with greener pretreatment processes in the context of the life cycle assessment.

Lignocellulosic Biomass Transformations via Greener Oxidative Pretreatment Processes: Access to Energy and Value-Added Chemicals

NASA Astrophysics Data System (ADS)

Den, Walter; Sharma, Virender K.; Lee, Mengshan; Nadadur, Govind; Varma, Rajender S.

2018-04-01

Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the problems associated with the conventional processes. The mechanisms of reaction pathways, selectivity and efficiency of end-products obtained using greener processes such as ozonolysis, photocatalysis, oxidative catalysis, electrochemical oxidation, and Fenton or Fenton-like reactions, as applied to depolymerization of lignocellulosic biomass are summarized with deliberation on future prospects of biorefineries with greener pretreatment processes in the context of the life cycle assessment.

Effect of iron ion on doxycycline photocatalytic and Fenton-based autocatatalytic decomposition.

PubMed

Bolobajev, Juri; Trapido, Marina; Goi, Anna

2016-06-01

Doxycycline plays a key role in Fe(III)-to-Fe(II) redox cycling and therefore in controlling the overall reaction rate of the Fenton-based process (H2O2/Fe(III)). This highlights the autocatalytic profile of doxycycline degradation. Ferric iron reduction in the presence of doxycycline relied on doxycycline-to-Fe(III) complex formation with an ensuing reductive release of Fe(II). The lower ratio of OH-to-contaminant in an initial H2O2/Fe(III) oxidation step than in that of classical Fenton (H2O2/Fe(II)) decreased the doxycycline degradation rate. The quantum yield of doxycycline in direct UV-C photolysis was 3.1 × 10(-3) M E(-1). In spite of doxycycline-Fe(III) complexes could produce the adverse effect on the doxycycline degradation in the UV/Fe(III) system some acceleration of the rate was observed upon irradiation of the Fe(III)-hydroxy complex. Acidic reaction media (pH 3.0) and the molar ratio of DC/Fe(III) = 2/1 favored the complex formation. Doxycycline close degradation rates and complete mineralization achieved for 120 min (Table 1) with both UV/H2O2 and UV/H2O2/Fe(III) indicated the unsubstantial role of the reduction of Fe(III) to Fe(II) in UV/H2O2/Fe(III) system efficacy. Thus, factors such as doxycycline's ability to form complexes with ferric iron and the ability of complexes to participate in a reductive pathway should be considered at a technological level in process optimization, with chemistry based on iron ion catalysis to enhance the doxycycline oxidative pathway. Copyright © 2016 Elsevier Ltd. All rights reserved.

Citric Acid-Modified Fenton's Reaction for the Oxidation of Chlorinated Ethylenes in Soil Solution Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seol, Yongkoo; Javandel, Iraj

Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in-situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varyingmore » H{sub 2}O{sub 2} concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H{sub 2}O{sub 2} relative to iron catalysts (Fe{sup 2+}/H{sub 2}O{sub 2} < 1/330) would result in lowering the efficiency of contaminant removal by iron chelations in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.« less

Behavior of a chlorinated ethene plume following source-area treatment with Fenton's reagent

USGS Publications Warehouse

Chapelle, F.H.; Bradley, P.M.; Casey, C.C.

2005-01-01

Monitoring data collected over a 6-year period show that a plume of chlorinated ethene-contaminated ground water has contracted significantly following treatment of the contaminant source area using in situ oxidation. Prior to treatment (1998), concentrations of perchloroethene (PCE) exceeded 4500 ??g/L in a contaminant source area associated with a municipal landfill in Kings Bay, Georgia. The plume emanating from this source area was characterized by vinyl chloride (VC) concentrations exceeding 800 ??g/L. In situ oxidation using Fenton's reagent lowered PCE concentrations in the source area below 100 ??g/L, and PCE concentrations have not rebounded above this level since treatment. In the 6 years following treatment, VC concentrations in the plume have decreased significantly. These concentration declines can be attributed to the movement of Fenton's reagent-treated water downgradient through the system, the cessation of a previously installed pump-and-treat system, and the significant natural attenuation capacity of this anoxic aquifer. While in situ oxidation briefly decreased the abundance and activity of microorganisms in the source area, this activity rebounded in <6 months. Nevertheless, the shift from sulfate-reducing to Fe(III)-reducing conditions induced by Fenton's treatment may have decreased the efficiency of reductive dechlorination in the injection zone. The results of this study indicate that source-area removal actions, particularly when applied to ground water systems that have significant natural attenuation capacity, can be effective in decreasing the areal extent and contaminant concentrations of chlorinated ethene plumes. Copyright ?? 2005 National Ground Water Association.

Citric acid-modified Fenton's reaction for the oxidation of chlorinated ethylenes in soil solution systems.

PubMed

Seol, Yongkoo; Javandel, Iraj

2008-06-01

Fenton's reagent, a solution of hydrogen peroxide and ferrous iron catalyst, is used for an in situ chemical oxidation of organic contaminants. Sulfuric acid is commonly used to create an acidic condition needed for catalytic oxidation. Fenton's reaction often involves pressure buildup and precipitation of reaction products, which can cause safety hazards and diminish efficiency. We selected citric acid, a food-grade substance, as an acidifying agent to evaluate its efficiencies for organic contaminant removal in Fenton's reaction, and examined the impacts of using citric acid on the unwanted reaction products. A series of batch and column experiments were performed with varying H2O2 concentrations to decompose selected chlorinated ethylenes. Either dissolved iron from soil or iron sulfate salt was added to provide the iron catalyst in the batch tests. Batch experiments revealed that both citric and sulfuric acid systems achieved over 90% contaminant removal rates, and the presence of iron catalyst was essential for effective decontamination. Batch tests with citric acid showed no signs of pressure accumulation and solid precipitations, however the results suggested that an excessive usage of H2O2 relative to iron catalysts (Fe2+/H2O2<1/330) would result in lowering the efficiency of contaminant removal by iron chelation in the citric acid system. Column tests confirmed that citric acid could provide suitable acidic conditions to achieve higher than 55% contaminant removal rates.

Degradation of imidacloprid using combined advanced oxidation processes based on hydrodynamic cavitation.

PubMed

Patil, Pankaj N; Bote, Sayli D; Gogate, Parag R

2014-09-01

The harmful effects of wastewaters containing pesticides or insecticides on human and aquatic life impart the need of effectively treating the wastewater streams containing these contaminants. In the present work, hydrodynamic cavitation reactors have been applied for the degradation of imidacloprid with process intensification studies based on different additives and combination with other similar processes. Effect of different operating parameters viz. concentration (20-60 ppm), pressure (1-8 bar), temperature (34 °C, 39 °C and 42 °C) and initial pH (2.5-8.3) has been investigated initially using orifice plate as cavitating device. It has been observed that 23.85% degradation of imidacloprid is obtained at optimized set of operating parameters. The efficacy of different process intensifying approaches based on the use of hydrogen peroxide (20-80 ppm), Fenton's reagent (H2O2:FeSO4 ratio as 1:1, 1:2, 2:1, 2:2, 4:1 and 4:2), advanced Fenton process (H2O2:Iron Powder ratio as 1:1, 2:1 and 4:1) and combination of Na2S2O8 and FeSO4 (FeSO4:Na2S2O8 ratio as 1:1, 1:2, 1:3 and 1:4) on the extent of degradation has been investigated. It was observed that near complete degradation of imidacloprid was achieved in all the cases at optimized values of process intensifying parameters. The time required for complete degradation of imidacloprid for approach based on hydrogen peroxide was 120 min where as for the Fenton and advance Fenton process, the required time was only 60 min. To check the effectiveness of hydrodynamic cavitation with different cavitating devices, few experiments were also performed with the help of slit venturi as a cavitating device at already optimized values of parameters. The present work has conclusively established that combined processes based on hydrodynamic cavitation can be effectively used for complete degradation of imidacloprid. Copyright © 2014 Elsevier B.V. All rights reserved.

Fungal hydroquinones contribute to brown rot of wood

Treesearch

Melissa R. Suzuki; Christopher G. Hunt; Carl J. Houtman; Zachary D. Dalebroux; Kenneth E. Hammel

2006-01-01

The fungi that cause brown rot of wood initiate lignocellulose breakdown with an extracellular Fenton system in which Fe2+ and H2O2 react to produce hydroxyl radicals (•OH), which then oxidize and cleave the wood holocellulose. One such fungus, Gloeophyllum trabeum, drives Fenton chemistry on defined media by reducing Fe3+ and O2 with two extracellular hydroquinones,...

Decolorizing textile wastewater with Fenton's reagent electrogenerated with a solar photovoltaic cell.

PubMed

Figueroa, Sandra; Vázquez, Leticia; Alvarez-Gallegos, A

2009-02-01

In this work it is demonstrated that Fenton's reagent can be electroproduced with abundant and cheap feedstock: oxygen saturated wastewater and solar energy. Experiments were carried out in a divided electrochemical flow cell using two electrodes: a three dimensional reticulated vitreous carbon cathode and stainless steel anode. Fenton's reagent is produced by oxygen reduction on the cathode in the presence of 1mM Fe(2+). The influence of electrolyte nature and its concentration and potential difference on the current efficiency, as well as the rate of Fenton's reagent electroproduction is discussed and it is concluded that over this extended range of conditions the current efficiency, for Fenton's reagent production, fell within the range 50-70%. It is possible to electroproduce a stoichiometric amount of Fenton reagent for the oxidation of 0.061mM Reactive Black 5 (in tap water+0.05M Na(2)SO(4), approximately pH 2.8). Similar results were obtained for solutions containing 0.1mM Acid Green 25. Some practical applications in the field of water treatment are included. The energy required for drive electrochemical reaction is supplied to the flow cell by means of a commercial solar panel.

Chemical oxidation of anthracite with hydrogen peroxide via the Fenton reaction

USGS Publications Warehouse

Heard, I.; Senftle, F.E.

1984-01-01

Solutions of 30% H2O2 ranging from pH = 0 to pH = 11.5 have been used to oxidize anthracite at room temperature. The inorganic impurities, primarily pyrite, catalysed the oxidation and reduction of H2O2 (the Fenton reaction) to form the hydroxyl radical; the oxidation of the organic matter was minimal and was observed only in strong acidic solutions (pH < 1.5). After acid demineralization, samples of the same anthracite underwent a significant enhancement of oxidation in both acid and alkaline solutions (pH = 0.4-11.5). As all the iron had been removed from the surface and the reactions were completed in a much shorter time, the oxidation mechanism must have been of a different nature than that for the untreated anthracite. A qualitative model based on the catalytic decomposition of H2O2 by activated carbon sites in the coal surface is used to explain the oxidation of the demineralized anthracite. ?? 1984.

Elimination of radiocontrast agent diatrizoic acid by photo-Fenton process and enhanced treatment by coupling with electro-Fenton process.

PubMed

Bocos, Elvira; Oturan, Nihal; Pazos, Marta; Sanromán, M Ángeles; Oturan, Mehmet A

2016-10-01

The removal of radiocontrast agent diatrizoic acid (DIA) from water was performed using photo-Fenton (PF) process. First, the effect of H2O2 dosage on mineralization efficiency was determined using ultraviolet (UV) irradiation. The system reached a maximum mineralization degree of 60 % total organic carbon (TOC) removal at 4 h with 20 mM initial H2O2 concentration while further concentration values led to a decrease in TOC abatement efficiency. Then, the effect of different concentrations of Fenton's reagents was studied for homogeneous Fenton process. Obtained results revealed that 0.25 mM Fe(3+) and 20 mM H2O2 were the best conditions, achieving 80 % TOC removal efficiency at 4 h treatment. Furthermore, heterogeneous PF treatment was developed using iron-activated carbon as catalyst. It was demonstrated that this catalyst is a promising option, reaching 67 % of TOC removal within 4 h treatment without formation of iron leachate in the medium. In addition, two strategies of enhancement for process efficiency are proposed: coupling of PF with electro-Fenton (EF) process in two ways: photoelectro-Fenton (PEF) or PF followed by EF (PF-EF) treatments, achieving in both cases the complete mineralization of DIA solution within only 2 h. Finally, the Microtox tests revealed the formation of more toxic compounds than the initial DIA during PF process, while, it was possible to reach total mineralization by both proposed alternatives (PEF or PF-EF) and thus to remove the toxicity of DIA solution.

Optimization of photo-Fenton process for the treatment of prednisolone.

PubMed

Díez, Aida María; Ribeiro, Ana Sofia; Sanromán, Maria Angeles; Pazos, Marta

2018-03-29

Prednisolone is a widely prescribed synthetic glucocorticoid and stated to be toxic to a number of non-target aquatic organisms. Its extensive consumption generates environmental concern due to its detection in wastewater samples at concentrations ranged from ng/L to μg/L that requests the application of suitable degradation processes. Regarding the actual treatment options, advanced oxidation processes (AOPs) are presented as a viable alternative. In this work, the comparison in terms of pollutant removal and energetic efficiencies, between different AOPs such as Fenton (F), photo-Fenton (UV/F), photolysis (UV), and hydrogen peroxide/photolysis (UV/H 2 O 2 ), was carried out. Light diode emission (LED) was the selected source to provide the UV radiation. The UV/F process revealed the best performance, reaching high levels of both degradation and mineralization with low energy consumption. Its optimization was conducted and the operational parameters were iron and H 2 O 2 concentrations and the working volume. Using the response surface methodology with the Box-Behnken design, the effect of independent variables and their interactions on the process response were effectively evaluated. Different responses were analyzed taking into account the prednisolone removal (TOC and drug abatements) and the energy consumptions associated. The obtained model showed an improvement of the UV/F process when treating smaller volumes and when adding high concentrations of H 2 O 2 and Fe 2+ . The validation of this model was successfully carried out, having only 5% of discrepancy between the model and the experimental results. Finally, the performance of the process when having a real wastewater matrix was also tested, achieving complete mineralization and detoxification after 8 h. In addition, prednisolone degradation products were identified. Finally, the obtained low energy permitted to confirm the viability of the process.

Photocatalytic properties of nano-structured TiO2-carbon films obtained by means of electrophoretic deposition.

PubMed

Peralta-Hernández, J M; Manríquez, J; Meas-Vong, Y; Rodríguez, Francisco J; Chapman, Thomas W; Maldonado, Manuel I; Godínez, Luis A

2007-08-17

Recent studies have shown that the light-absorption and photocatalytic efficiencies of TiO2 can be improved by coupling TiO2 nano-particles with nonmetallic dopants, such as carbon. In this paper, we describe the electrophoretic preparation of a novel TiO2-carbon nano-composite photocatalyst on a glass indium thin oxide (ITO) substrate. The objective is to take better advantage of the (e-/h+) pair generated by photoexcitation of semiconducting TiO2 particles. The transfer of electrons (e-) into adjacent carbon nano-particles promotes reduction of oxygen to produce hydrogen peroxide (H2O2) which, in the presence of iron ions, can subsequently form hydroxyl radicals (*OH) via the Fenton reaction. At the same time, *OH is formed from water by the (h+) holes in the TiO2. Thus, the *OH oxidant is produced by two routes. The efficiency of this photolytic-Fenton process was tested with a model organic compound, Orange-II (OG-II) azo dye, which is employed in the textile industry.

Evaluation of an alternative method for wastewater treatment containing pesticides using solar photocatalytic oxidation and constructed wetlands.

PubMed

Berberidou, Chrysanthi; Kitsiou, Vasiliki; Lambropoulou, Dimitra A; Antoniadis, Αpostolos; Ntonou, Eleftheria; Zalidis, George C; Poulios, Ioannis

2017-06-15

The present study proposes an integrated system based on the synergetic action of solar photocatalytic oxidation with surface flow constructed wetlands for the purification of wastewater contaminated with pesticides. Experiments were conducted at pilot scale using simulated wastewater containing the herbicide clopyralid. Three photocatalytic methods under solar light were investigated: the photo-Fenton and the ferrioxalate reagent as well as the combination of photo-Fenton with TiO 2 P25, which all led to similar mineralization rates. The subsequent treatment in constructed wetlands resulted in further decrease of DOC and inorganic ions concentrations, especially of NO 3 - . Clopyralid was absent in the outlet of the wetlands, while the concentration of the detected intermediates was remarkably low. These findings are in good agreement with the results of phytotoxicity of the wastewater, after treatment with the ferrioxalate/wetlands process, which was significantly reduced. Thus, this integrated system based on solar photocatalysis and constructed wetlands has the potential to effectively detoxify wastewater containing pesticides, producing a purified effluent which could be exploited for reuse applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation of sulfamethazine using Fe3O4-Mn3O4/reduced graphene oxide hybrid as Fenton-like catalyst.

PubMed

Wan, Zhong; Wang, Jianlong

2017-02-15

In this paper, Fe 3 O 4 -Mn 3 O 4 /reduced graphene oxide (RGO) hybrid was synthesized through polyol process and impregnation method and used as heterogeneous Fenton-like catalyst for degradation of sulfamethazine (SMT) in aqueous solution. The hybrid catalyst had higher catalytic efficiency compared with Fe 3 O 4 -Mn 3 O 4 and Mn 3 O 4 as catalyst for degradation of SMT . The effects of pH value, H 2 O 2 concentration, catalyst dosage, initial SMT concentration and temperature on SMT degradation were investigated. The removal efficiency of SMT was about 98% at following optimal conditions: pH=3, T=35°C, Fe 3 O 4 /Mn 3 O 4 -RGO composites=0.5g/L, H 2 O 2 =6mM. The inhibitor experiments indicated that the main active species was hydroxyl radicals (·OH) on catalyst surface. At last, the possible catalytic mechanism was proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthetic olive mill wastewater treatment by Fenton's process in batch and continuous reactors operation.

PubMed

Esteves, Bruno M; Rodrigues, Carmen S D; Madeira, Luís M

2017-11-04

Degradation of total phenol (TPh) and organic matter, (expressed as total organic carbon TOC), of a simulated olive mill wastewater was evaluated by the Fenton oxidation process under batch and continuous mode conditions. A mixture of six phenolic acids usually found in these agro-industrial wastewaters was used for this purpose. The study focused on the optimization of key operational parameters of the Fenton process in a batch reactor, namely Fe 2+ dosage, hydrogen peroxide concentration, pH, and reaction temperature. On the assessment of the process efficiency, > 99% of TPh and > 56% of TOC removal were attained when [Fe 2+ ] = 100 ppm, [H 2 O 2 ] = 2.0 g/L, T = 30 °C, and initial pH = 5.0, after 300 min of reaction. Under those operational conditions, experiments on a continuous stirred-tank reactor (CSTR) were performed for different space-time values (τ). TOC and TPh removals of 47.5 and 96.9%, respectively, were reached at steady-state (for τ = 120 min). High removal of COD (> 75%) and BOD 5 (> 70%) was achieved for both batch and CSTR optimum conditions; analysis of the BOD 5 /COD ratio also revealed an increase in the effluent's biodegradability. Despite the high removal of lumped parameters, the treated effluent did not met the Portuguese legal limits for direct discharge of wastewaters into water bodies, which indicates that coupled chemical-biological process may be the best solution for real olive mill wastewater treatment.

Ferrocene functionalized graphene based electrode for the electro-Fenton oxidation of ciprofloxacin.

PubMed

Divyapriya, Govindaraj; Nambi, Indumathi; Senthilnathan, Jaganathan

2018-05-26

Ferrocene functionalized graphene based graphite felt electrode was firstly investigated for heterogeneous electro-Fenton oxidation of ciprofloxacin in neutral pH condition. Electrochemical reduction of Ferrocene functionalized graphene oxide (Fc-ErGO) was performed by cyclic voltammetry technique. At neutral pH condition, Fc-ErGO electrode (0.035 min ─1 ) exhibited ∼3 times and ∼9 times higher removal rates in comparison with plane ErGO (0.010 min ─1 ) and plane graphite felt (0.004 min ─1 ) electrodes respectively. The effect of pH and applied potential were studied for the degradation of ciprofloxacin in Fc-ErGO based electrode. Higher removal rate was observed at acidic pH (0.222 min ─1 ), whereas alkaline pH showed lower removal efficiency (0.014 min ─1 ). > 99% removal of ciprofloxacin was achieved with in 15 min and 120 min of reactions period at pH 3.0 and pH 7.0, respectively. H 2 O 2 generation was found to be high in plane ErGO electrode system in all of the pH conditions. Owing to the high redox ability of ferrocene, Fc-ErGO electrode generated high concentration of OH radicals (426 μM pH 3.0; 247 μM pH 7.0; 210 μM pH 9.0) than ErGO and plane graphite felt electrodes; The electrode reusability study was performed to understand the electrode stability. There was no significant change in removal efficiency even after the 5th cycle of reusability study at both acidic and neutral conditions. The possible mechanism of oxidation in Fc-ErGO based electro-Fenton process was also proposed based on the continuous monitoring of H 2 O 2 and OH radicals generated in the system. Copyright © 2018. Published by Elsevier Ltd.

Comparison of adsorption and photo-Fenton processes for phenol and paracetamol removing from aqueous solutions: Single and binary systems

NASA Astrophysics Data System (ADS)

Rad, Leila Roshanfekr; Haririan, Ismaeil; Divsar, Faten

2015-02-01

In the present study, adsorption and photo-Fenton processes have been compared for the removal of phenol and paracetamol from aqueous solutions in a single and binary systems. NaX nanozeolites and cobalt ferrite nanoparticles were used during adsorption and photo-Fenton processes, respectively. Both nanoparticles were synthesized using microwave heating method. The synthesized nanoparticles were characterized using powder X-ray diffraction (XRD) and scanning electronic microscopy (SEM) analysis. Based on results, more than 99% removing percentages of phenol and paracetamol were obtained during photo-Fenton process at initial concentrations of 10, 20, 50, 100 and 200 mg/L of phenol and paracetamol. Moreover, the complete removing of phenol and paracetamol was only achieved at lower initial concentrations than 10 mg/L for phenol and paracetamol during adsorption process. The results showed a significant dependence of the phenol and paracetamol removing on the initial concentrations of phenol and paracetamol for selection of process. The photo-Fenton process could be considered an alternative method in higher initial concentrations of phenol and paracetamol. However, the adsorption process due to economical issue was preferred for phenol and paracetamol removing at lower initial concentrations. The kinetic data of photo-Fenton and adsorption processes were well described using first-order and pseudo-second-order kinetic models. The results of phenol and paracetamol removing in a binary system confirmed the obtained results of single removing of phenol and paracetamol in selection of process.

Reuse of Fenton sludge as an iron source for NiFe2O4 synthesis and its application in the Fenton-based process.

PubMed

Zhang, Hui; Liu, Jianguo; Ou, Changjin; Faheem; Shen, Jinyou; Yu, Hongxia; Jiao, Zhenhuan; Han, Weiqing; Sun, Xiuyun; Li, Jiansheng; Wang, Lianjun

2017-03-01

The potentially hazardous iron-containing sludge from the Fenton process requires proper treatment and disposal, which often results in high treatment cost. In this study, a novel method for the reuse of Fenton sludge as an iron source for the synthesis of nickel ferrite particles (NiFe 2 O 4 ) is proposed. Through a co-precipitation method followed by sintering at 800°C, magnetic NiFe 2 O 4 particles were successfully synthesized, which was confirmed by powder X-ray diffraction (XRD), scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The synthesized NiFe 2 O 4 could be used as an efficient catalyst in the heterogeneous Fenton process. In phenol degradation with H 2 O 2 or NiFe 2 O 4 alone, the phenol removal efficiencies within the reaction time of 330min were as low as 5.9%±0.1% and 13.5%±0.4%, respectively. However, in the presence of both NiFe 2 O 4 and H 2 O 2 , phenol removal efficiency as high as 95%±3.4% could be achieved, indicating the excellent catalytic performance of NiFe 2 O 4 in the heterogeneous Fenton process. Notably, a rapid electron exchange between Ni II and Fe III ions in the NiFe 2 O 4 structure could be beneficial for the Fenton reaction. In addition, the magnetic catalyst was relatively stable, highly active and recoverable, and has potential applications in the Fenton process for organic pollutant removal. Copyright © 2016. Published by Elsevier B.V.

Treatment of reverse osmosis (RO) concentrate by the combined Fe/Cu/air and Fenton process (1stFe/Cu/air-Fenton-2ndFe/Cu/air).

PubMed

Ren, Yi; Yuan, Yue; Lai, Bo; Zhou, Yuexi; Wang, Juling

2016-01-25

To decompose or transform the toxic and refractory reverse osmosis (RO) concentrate and improve the biodegradability, 1stFe/Cu/air-Fenton-2ndFe/Cu/air were developed to treat RO concentrate obtained from an amino acid production plant in northern China. First, their operating conditions were optimized thoroughly. Furthermore, 5 control experiments were setup to confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and synergistic reaction between Fe/Cu/air and Fenton. The results suggest that the developed method could obtain high COD removal (65.1%) and BOD5/COD ratio (0.26) due to the synergistic reaction between Fe/Cu/air and Fenton. Under the optimal conditions, the influent and effluent of 1stFe/Cu/air-Fenton-2ndFe/Cu/air and 5 control experiments were analyzed by using UV, FTIR, EEM and LC, which confirm the superiority of 1stFe/Cu/air-Fenton-2ndFe/Cu/air. Therefore, the developed method in this study is a promising process for treatment of RO concentrate. Copyright © 2015 Elsevier B.V. All rights reserved.

Eco-friendly processing in enzymatic xylooligosaccharides production from corncob: Influence of pretreatment with sonocatalytic-synergistic Fenton reaction and its antioxidant potentials.

PubMed

Kawee-Ai, Arthitaya; Srisuwun, Aungkana; Tantiwa, Nidtaya; Nontaman, Wimada; Boonchuay, Pinpanit; Kuntiya, Ampin; Chaiyaso, Thanongsak; Seesuriyachan, Phisit

2016-07-01

Delignification can be considered as a feasible process to pretreat lignocellulosic biomass in xylooligosaccharides production after the performance and efficiency has been improved through a few modifications. This study compared various pretreatment strategies such as Fenton, sonocatalytic, and sonocatalytic-synergistic Fenton employed on corncob in order to expose lignin content and saccharides to enhance the xylooligosaccharides yield by enzymatic hydrolysis. The dissolution of lignin and xylooligosaccharides production of corncob was enhanced by ultrasound assisted TiO2 and Fenton reaction. The corncob pretreated with a sonocatalytic-synergistic Fenton reaction gave the highest release of the lignin concentration level (1.03 g/L), dissolution level (80.25%), and xylooligosaccharides content (46.45 mg/g substrate). A two-step pretreatment processes consisting of the alkali treatment (pretreatment) and sonocatalytic-synergistic Fenton process (posttreatment) illustrated that subsequent enzymatic hydrolysis could be enhanced considerably. The release of the lignin concentration and xylooligosaccharides content were 33.20 g/L and 174.81 mg/g substrate, respectively. The antioxidant potential of xylooligosaccharides showed significant differences regarding the amount of xylooligosaccharides and the phenolic compounds produced. Copyright © 2015 Elsevier B.V. All rights reserved.

Degradation pathway of the naphthalene azo dye intermediate 1-diazo-2- naphthol-4-sulfonic acid using Fenton's reagent.

PubMed

Zhu, Nanwen; Gu, Lin; Yuan, Haiping; Lou, Ziyang; Wang, Liang; Zhang, Xin

2012-08-01

Degradation of naphthalene dye intermediate 1-diazo-2- naphthol-4-sulfonic acid (1,2,4-Acid) by Fenton process has been studied in depth for the purpose of learning more about the reactions involved in the oxidation of 1,2,4-Acid. During 1,2,4-Acid oxidation, the solution color initially takes on a dark red, then to dark black associated with the formation of quinodial-type structures, and then goes to dark brown and gradually disappears, indicating a fast degradation of azo group. The observed color changes of the solution are a result of main reaction intermediates, which can be an indicator of the level of oxidization reached. Nevertheless, complete TOC removal is not accomplished, in accordance with the presence of resistant carboxylic acids at the end of the reaction. The intermediates generated along the reaction time have been identified and quantified. UPLC-(ESI)-TOF-HRMS analysis allows the detection of 19 aromatic compounds of different size and complexity. Some of them share the same accurate mass but appear at different retention time, evidencing their different molecular structures. Heteroatom oxidation products like SO(4)(2-) have also been quantified and explanations of their release are proposed. Short-chain carboxylic acids are detected at long reaction time, as a previous step to complete the process of dye mineralization. Finally, considering all the findings of the present study and previous related works, the evolution from the original 1,2,4-Acid to the final products is proposed in a general reaction scheme. Copyright © 2012 Elsevier Ltd. All rights reserved.

EDDS as complexing agent for enhancing solar advanced oxidation processes in natural water: Effect of iron species and different oxidants.

PubMed

Miralles-Cuevas, S; Oller, I; Ruíz-Delgado, A; Cabrera-Reina, A; Cornejo-Ponce, L; Malato, S

2018-03-19

The main purpose of this pilot plant study was to compare degradation of five microcontaminants (MCs) (antipyrine, carbamazepine, caffeine, ciprofloxacin and sulfamethoxazole at 100 μg/L) by solar photo-Fenton mediated by EDDS and solar/Fe:EDDS/S 2 O 8 2- . The effects of the Fe:EDDS ratio (1:1 and 1:2), initial iron species (Fe(II) or Fe(III) at 0.1 mM) and oxidizing agent (S 2 O 8 2- or H 2 O 2 at 0.25-1.5 mM) were evaluated. The higher the S 2 O 8 2- concentration, the faster MC degradation was, with S 2 O 8 2- consumption always below 0.6 mM and similar degradation rates with Fe(II) and Fe(III). Under the best conditions (Fe 0.1 mM, Fe:EDDS 1:1, S 2 O 8 2- 1 mM) antipyrine, carbamazepine, caffeine, ciprofloxacin and sulfamethoxazole at 100 μg/L where 90% eliminated applying a solar energy of 2 kJ/L (13 min at 30 W/m 2 solar radiation <400 nm). Therefore, S 2 O 8 2- promotes lower consumption of EDDS as Fe:EDDS 1:1 was better than Fe:EDDS 1:2. In photo-Fenton-like processes at circumneutral pH, EDDS with S 2 O 8 2- is an alternative to H 2 O 2 as an oxidizing agent. Copyright © 2018 Elsevier B.V. All rights reserved.

Soil washing in combination with homogeneous Fenton-like oxidation for the removal of 2,4,4'-trichlorodiphenyl from soil contaminated with capacitor oil.

PubMed

Ma, Xiao-Hong; Zhao, Ling; Lin, Zhi-Rong; Dong, Yuan-Hua

2016-04-01

Detoxification by chemical oxidation of polychlorinated biphenyls (PCBs) in contaminated soils is very difficult and inefficient because PCBs typically associate with the solid phase or exist as non-aqueous-phase liquids due to their low solubility and slow desorption rates, and thus, they are difficult to remove from soils by using traditional, water-based elution techniques. Surfactant can enhance washing efficiency of PCBs from contaminated soils. This study used Brij 58, Brij 30, Tween 80, and 2-hydroxypropyl-β-cyclodextrin (HPCD) to solubilize 2,4,4'-trichlorodiphenyl (PCB28) from soil contaminated with capacitor oil into solution. The feasibility of PCB28 oxidation in soil washing wastewater through a Fe(3+)-catalyzed Fenton-like reaction was subsequently examined. Washing with 10 g L(-1) Brij 58 solution showed the highest extraction efficiency (up to 61.5 %) compared with that of the three other surfactants. The total concentration of PCB28 in contaminated soil at 25 °C after 48-h extraction was 286 mg L(-1). In contrast to conditions in which no washing agent was added, addition of the four washing agents decreased the efficiency of PCB28 degradation by the Fenton-like reaction, with the decrease due to addition of 10 g L(-1) Brij 58 solution being the smallest. The optimal concentration of H2O2 for preventing its useless decomposition was found to be 50 mM. The efficiency of PCB28 removal was lower when the initial concentration of PCB28 treated in the Fenton-like reaction was higher. The degradation efficiencies of PCB28 at initial concentrations of 0.1, 10, and 176 mg L(-1) in 10 g L(-1) Brij 58 solution at 25 °C and pH 3.0 and 9 h of reaction using 50 mM H2O2 were 64.1, 42.0, and 34.6 %, respectively. This result indicates that soil washing combined with Fenton-like oxidation may be a practical approach for the remediation of PCB-contaminated soil.

Enhancement of anaerobic digestibility of waste activated sludge using photo-Fenton pretreatment.

PubMed

Heng, Gan Chin; Isa, Mohamed Hasnain; Lim, Jun-Wei; Ho, Yeek-Chia; Zinatizadeh, Ali Akbar Lorestani

2017-12-01

Biological treatments, such as activated sludge process, are common methods to treat municipal and industrial wastewaters. However, they produce huge amounts of waste activated sludge (WAS). The excess sludge treatment and disposal are a challenge for wastewater treatment plants due to economic, environmental, and regulatory factors. In this study, photo-Fenton pretreatment (oxidation using hydrogen peroxide and iron catalyst aided with UV light) was optimized using response surface methodology (RSM) and central composite design (CCD) to determine the effects of three operating parameters (H 2 O 2 dosage, H 2 O 2 /Fe 2+ molar ratio, and irradiation time) on disintegration and dewaterability of WAS. MLVSS removal, capillary suction time (CST) reduction, sCOD, and EPS were obtained as 70%, 25%, 12,000 mg/L, and 500 mg/L, respectively, at the optimal conditions, i.e., 725 g H 2 O 2 /kg TS, H 2 O 2 /Fe 2+ molar ratio 80, and irradiation time 40 min. Two batch-fed completely mixed mesophilic anaerobic digesters were then operated at 15-day solid retention time (SRT) and 37 ± 0.5 °C to compare the digestibility of untreated and photo-Fenton pretreated sludge in terms of volatile solids (VS) reduction, COD removal, and biogas production at steady-state operations. Photo-Fenton pretreatment followed by anaerobic digestion of WAS was very effective and yielded 75.7% total VS reduction, 81.5% COD removal, and 0.29-0.31 m 3 /kg VS fed ·d biogas production rate, compared to 40.7% total VS solid reduction, 54.7% COD removal, and 0.12-0.17 m 3 /kg VS fed ·d biogas production rate for control. Thus, photo-Fenton can be a useful pretreatment step in sludge management.

Characterization of changes in floc morphology, extracellular polymeric substances and heavy metals speciation of anaerobically digested biosolid under treatment with a novel chelated-Fe2+ catalyzed Fenton process.

PubMed

He, Juanjuan; Yang, Peng; Zhang, Weijun; Cao, Bingdi; Xia, Hua; Luo, Xi; Wang, Dongsheng

2017-11-01

A novel chelated-Fe 2+ catalyzed Fenton process (CCFP) was developed to enhance dewatering performance of anaerobically digested biosolid, and changes in floc morphology, extracellular polymeric substances (EPS) and heavy metals speciation were also investigated. The results showed that addition of chelating agents caused EPS solubilization by binding multivalent cations. Like traditional Fenton, CCFP performed well in improving anaerobically digested sludge dewatering property. The highly active radicals (OH, O 2 - ) produced in classical Fenton and CCFP were responsible for sludge flocs destruction and consequently degradation of biopolymers into small molecules. Furthermore, more plentiful pores and channels were presented in cake after Fenton treatment, which was conducive to water drainage under mechanical compression. Additionally, a portion of active heavy metals in the form of oxidizable and reducible states were dissolved under CCFP. Therefore, CCFP could greatly simplify the operating procedure of Fenton conditioning and improve its process adaptability for harmless treatment of biological sludge. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cu-modified alkalinized g-C3N4 as photocatalytically assisted heterogeneous Fenton-like catalyst

NASA Astrophysics Data System (ADS)

Dong, Qimei; Chen, Yingying; Wang, Lingli; Ai, Shasha; Ding, Hanming

2017-12-01

Alkalinized graphitic carbon nitride (CNK-OH) has been synthesized by one-step thermal poly-condensation method, and Cu-modified alkalinized g-C3N4 (Cu-CNK-OH) has been prepared by impregnation approach over CNK-OH. These copper species in Cu-CNK-OH are embedded in the frame of CNK-OH mostly via the Cu-N bonds. Cu-CNK-OH has been employed as a heterogeneous Fenton-like catalyst to degrade rhodamine B (RhB). Both the production efficiency of hydroxyl radicals and the transformation rate of Cu(II)/Cu(I) redox pair increase under visible-light irradiation. As a result, Cu-CNK-OH exhibits improved Fenton-like catalytic activity on the degradation of RhB. The synergetic interaction between Fenton-like process and photocatalytic process also contributes such improvement. The hydroxyl radicals and holes are the major reactive species in the photocatalytically assisted Fenton-like process. This study provides a valuable strategy for metal modification of alkalinized g-C3N4 with enhanced Fenton-like catalytic performance for the degradation of organic contaminants.

Decontamination of soil containing POPs by the combined action of solid Fenton-like reagents and microwaves.

PubMed

Cravotto, Giancarlo; Di Carlo, Stefano; Ondruschka, Bernd; Tumiatti, Vander; Roggero, Carlo Maria

2007-10-01

The effect on halogenated aromatics of solid, non-toxic oxidants such as sodium percarbonate and the urea/hydrogen peroxide complex (Fenton-like reagents) was investigated. A microwaves-assisted, solvent-free method for soil decontamination is presented. It marks a considerable advance in the search of more efficient, environment-friendly procedures for the degradative oxidation of persistent organic pollutants. Residual pollutants in treated soil samples were determined by GC/MS analysis after solvent extraction or direct thermal desorption. Results showed that 4-chloronaphthol, 2,4-dichlorophenoxyacetic acid and p-nonylphenol had been degraded completely, 2,4-dibromophenol to a large extent.

Removal of residual contaminants in petroleum-contaminated soil by Fenton-like oxidation.

PubMed

Lu, Mang; Zhang, Zhongzhi; Qiao, Wei; Guan, Yueming; Xiao, Meng; Peng, Chong

2010-07-15

The degradation of bioremediation residues by hydrogen peroxide in petroleum-contaminated soil was investigated at circumneutral pH using a Fenton-like reagent (ferric ion chelated with EDTA). Batch tests were done on 20 g soil suspended in 60 mL aqueous solution containing hydrogen peroxide and Fe(3+)-EDTA complex under constant stirring. A slurry reactor was used to treat the soil based on the optimal reactant conditions. Contaminants were characterized by Fourier transform infrared spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry. The results showed that the optimal treatment condition was: the molar ratio of hydrogen peroxide to iron=200:1, and pH 7.0. Under the optimum condition, total dichloromethane-extractable organics were reduced from 14,800 to 2300 mg kg(-1) soil when the accumulative H(2)O(2) dosage was 2.45 mol kg(-1) soil during the reactor treatment. Abundance of viable cells was lower in incubated Fenton-like treated soil than in untreated soil. Oxidation of contaminants produced remarkable compositional and structural modifications. A fused ring compound, identified as C(34)H(38)N(1), was found to exhibit the greatest resistance to oxidation. 2010 Elsevier B.V. All rights reserved.

Preparation of a new Fenton-like catalyst from red mud using molasses wastewater as partial acidifying agent.

PubMed

Wei, Guangtao; Shao, Luhua; Mo, Jihua; Li, Zhongmin; Zhang, Linye

2017-06-01

Using molasses wastewater as partial acidifying agent, a new Fenton-like catalyst (ACRM sm ) was prepared through a simple process of acidification and calcination using red mud as main material. With molasses wastewater, both the free alkali and the chemically bonded alkali in red mud were effectively removed under the action of H 2 SO 4 and molasses wastewater, and the prepared ACRM sm was a near-neutral catalyst. The ACRM sm preparation conditions were as follows: for 3 g of red mud, 9 mL of 0.7 mol/L H 2 SO 4 plus 2 g of molasses wastewater as the acidifying agent, calcination temperature 573 K, and calcination time 1 h. Iron phase of ACRM sm was mainly α-Fe 2 O 3 and trace amount of carbon existed in ACRM sm . The addition of molasses wastewater not only effectively reduced the consumption of H 2 SO 4 in acidification of red mud but also resulted in the generation of carbon and significantly improved the distribution of macropore in prepared ACRM sm . It was found that near-neutral pH of catalyst, generated carbon, and wide distribution of macropore were the main reasons for the high catalytic activity of ACRM sm . The generated carbon and wide distribution of macropore were entirely due to the molasses wastewater added. In degradation of orange II, ACRM sm retained most of its catalytic stability and activity after five recycling times, indicating ACRM sm had an excellent long-term stability in the Fenton-like process. Furthermore, the performance test of settling showed ACRM sm had an excellent settleability. ACRM sm was a safe and green catalytic material used in Fenton-like oxidation for wastewater treatment.

Different treatment strategies for highly polluted landfill leachate in developing countries.

PubMed

Mahmud, Kashif; Hossain, Md Delwar; Shams, Shahriar

2012-11-01

The aim of this research was to determine appropriate treatment technique for effective treatment of heavily polluted landfill leachate. We accomplished several treatment experiments: (i) aerobic biological treatment, (ii) chemical coagulation, (iii) advanced oxidation process (AOP) and (iv) several combined treatment strategies. Efficiency of these treatment procedures were monitored by analysing COD and colour removal. Leachate used for this study was taken from Matuail landfill site at Dhaka city. With extended aeration process which is currently used in Matuail landfill site for leachate treatment, maximum COD and colour removal of 36% and 20%, respectively could be achieved with optimum retention period of 7 days. With optimum aluminium sulphate dose of 15,000 mg/L and pH value of 7.0, maximum COD and colour removals of 34% and 66%, respectively were observed by using chemical coagulation. With optimum pH of 5.0 and optimum dosages of reagents having H(2)O(2)/Fe(2+) molar ratio of 1.3 the highest removal of COD and colour were found 68% and 87%, respectively with sludge production of 55%. Fenton treatment which is an advanced oxidation process was the most successful between these three separate treatment procedures. Among the combined treatment options performed, extended aeration followed by Fenton method was the most suitable one. Copyright © 2011 Elsevier Ltd. All rights reserved.

Treatment of urban river contaminated sediment with ex situ advanced oxidation processes: technical feasibility, environmental discharges and cost-performance analysis.

PubMed

Yan, Dickson Y S; Liu, Tongzhou; Lo, Irene M C

2015-01-01

The technical feasibility, environmental discharges and cost-performance of urban river contaminated sediment treatment with ex situ advanced oxidation processes were evaluated for the purpose of achieving an ideal treatment goal (for marine disposal) and a cost-performance treatment goal (for beneficially reusing as a filling material). Sediment samples were collected from a river located in southern China. To achieve the ideal treatment goal, sequential treatments (Fenton's reaction+activated persulphate oxidation) were carried out. One-step Fenton's reaction was applied to achieve the cost-performance treatment goal. The resulting effluent was treated and discharged, and sludge generated in wastewater treatment was characterized. The resources input throughout the treatment processes were recorded for cost estimation. After the treatment designed for achieving the ideal treatment goal, most pollutants fulfilled the treatment goal except Pb, Cd, Hg and Ag, probably because these four metals were present mainly in stable fractions of the sediment. The cost-performance treatment goal was achieved in view of low pollutant contents in the toxicity characteristic leaching procedure leachate of treated sediment. The cost for achieving the cost-performance treatment goal is much less than that for achieving the ideal treatment goal. The major cost difference is attributed to chemical cost. Stringent sediment treatment goals based on existing standards would lead to massive chemical use, complex treatment and hence huge cost. A simpler treatment with fewer chemicals is adequate for sediment beneficially reused as a filling material, and is economically more advantageous than handling sediment for marine disposal.

Assessment of the best available wastewater management techniques for a textile mill: cost and benefit analysis.

PubMed

Dogan, Bugce; Kerestecioglu, Merih; Yetis, Ulku

2010-01-01

In the present study, several water recovery and end-of-pipe wastewater treatment alternatives were evaluated towards the evaluation of Best Available Techniques (BATs) for the management of wastewaters from a denim textile mill in accordance with the European Union's Integrated Pollution Prevention and Control (IPPC) Directive. For this purpose, an assessment that translates the key environmental aspects into a quantitative measure of environmental performance and also financial analysis was performed for each of the alternatives. The alternatives considered for water recovery from dyeing wastewaters were nanofiltration (NF) with coagulation and/or microfiltration (MF) pre-treatment, ozonation or peroxone and Fenton oxidation. On the other hand, for the end-of-pipe treatment of the mill's mixed wastewater, ozonation, Fenton oxidation, membrane bioreactor (MBR) and activated sludge (AS) process followed by membrane filtration technologies were evaluated. The results have indicated that membrane filtration process with the least environmental impacts is the BAT for water recovery. On the other side, MBR technology has appeared as the BAT for the end-of-pipe treatment of the mill's mixed wastewater. A technical and financial comparison of these two BAT alternatives revealed that water recovery via membrane filtration from dyeing wastewaters is selected as the BAT for the water and wastewater management in the mill.

Pd/RGO modified carbon felt cathode for electro-Fenton removing of EDTA-Ni.

PubMed

Zhang, Zhen; Zhang, Junya; Ye, Xiaokun; Hu, Yongyou; Chen, Yuancai

Ethylenediaminetetraacetic acid (EDTA) forms stable complexes with toxic metals such as nickel due to its strong chelation. The electro-Fenton (EF) process using a cathode made from palladium (Pd), reduced graphene oxide (RGO) and carbon felt, fed with air, exhibited high activities and stability for the removal of 10 mg L(-1) EDTA-Ni solution. Pd/RGO catalyst was prepared by one-pot synthesis; the scanning electron microscopy and X-ray diffraction analysis indicated nanoparticles and RGO were well distributed on carbon felt, forming three dimensional architecture with both large macropores and a mesoporous structure. The cyclic voltammetric results showed that the presence of RGO in Pd/RGO/carbon felt significantly increased the current response of two-electron reduction of O2 (0.45 V). The key factors influencing the removal efficiency of EDTA-Ni, such as pH, current and Fe(2+) concentration, were investigated. Under the optimum conditions, the removal efficiency of EDTA-Ni reached 83.8% after 100 min EF treatment. Mechanism analysis indicated that the introduction of RGO in Pd/RGO/carbon felt significantly enhanced the electrocatalytic activities by inducing •OH in the EF process; direct H2O2 oxidation still accounted for a large amount of EDTA-Ni removal efficiency.

Novel low-cost Fenton-like layered Fe-titanate catalyst: preparation, characterization and application for degradation of organic colorants.

PubMed

Chen, Yongzhou; Li, Nian; Zhang, Ye; Zhang, Lide

2014-05-15

Novel low-cost layered Fe-titanate catalyst for photo-Fenton degradation of organic contaminants was successfully developed by ion exchange of Fe(3+) with Na(+) layered nano Na-titanates which was prepared by alkali hydrothermal method. The as prepared materials were characterized by powder X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectrometer (EDX). The catalytic activity of the Fe-titanate catalyst was evaluated by the decolorization of three different dyes (rhodamine 6G (R6G), methyl blue (MB), and methyl orange (MO)) under UV irradiation at room temperature. Effect of several important factors such as Fe loading in the catalyst, initial solution pH, catalyst dosage, H2O2 amount, and reaction time was systematically studied. It was found that the decolorization was very efficient for all three dyes. The efficiency reached 98% for R6G, 98.5% for MB, and 97% for MO, respectively, under optimal conditions. The oxidation process was quick, and only 15 min is needed for all three dyes. Moreover, the Fe-titanate catalyst could be used in a wider and near neutral pH range compared with classic Fenton systems which need to be operated at around pH 3.0. Kinetic analysis results showed that the oxidation kinetics was accurately represented by pseudo-first-order model. More importantly, the catalyst was very stable and could be reused for at least four cycles when operated under near neutral pH. The Fe leaching from the catalyst measured was almost negligible, which not only demonstrated the stability of the catalyst, but also avoided the formation of secondary Fe pollution. Therefore, the reported Fe-titanates are promising nanomaterials which can be used as Fenton like catalyst for the degradation of organic contaminant in wastewater. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Feasibility of bioleaching combined with Fenton-like reaction to remove heavy metals from sewage sludge.

PubMed

Zhu, Yi; Zeng, Guangming; Zhang, Panyue; Zhang, Chang; Ren, Miaomiao; Zhang, Jiachao; Chen, Ming

2013-08-01

Feasibility of bioleaching combining with Fenton-like reaction to remove heavy metals from sewage sludge was investigated. After 5-day bioleaching, the sludge pH decreased from 6.95 to 2.50, which satisfied the acidic conditions for Fenton-like reaction. Meanwhile, more than 50% of sludge-borne heavy metals were dissolved except for Pb. The bioleached sludge was further oxidized with Fenton-like reaction, with an optimal H2O2 dosage of 5 g/L, the Cu, Zn, Pb and Cd removal reached up to 75.3%, 72.6%, 34.5% and 65.4%, respectively, and the residual content of heavy metals in treated sludge meets the requirement of Disposal of Sludge from Municipal Wastewater Treatment Plant - Control Standards for Agricultural Use (CJ/T 309-2009) of China for A grade sludge. Bioleaching combined with Fenton-like reaction was the most effective method for heavy metal removal, compared with 15-day bioleaching and inorganic acid leaching with 10% H2SO4, 10% HCl and 10% HNO3. Copyright © 2013 Elsevier Ltd. All rights reserved.

Removal of organic micropollutants from drinking water by a novel electro-Fenton filter: Pilot-scale studies.

PubMed

Plakas, Konstantinos V; Sklari, Stella D; Yiankakis, Dimitrios A; Sideropoulos, Georgios Th; Zaspalis, Vassilis T; Karabelas, Anastasios J

2016-03-15

To assess the performance of a novel 'filter'-type electro-Fenton (EF) device, results are reported from pilot-scale studies of continuous water treatment, to degrade diclofenac (DCF), a typical organic micro-pollutant, with no addition of oxidants. The novel 'filter' consisted of three pairs of anode/cathode electrodes made of carbon felt, with cathodes impregnated with iron nanoparticles (γ-Fe2O3/F3O4 oxides). The best 'filter' performance was obtained at applied potential of 2 V and low water superficial velocities (∼0.09 cm/s), i.e., the mineralization current efficiency (MCE) was >20%, during continuous steady state treatment of tap water with low DCF concentrations (16 μg/L). The EF 'filter' exhibited satisfactory stability regarding both electrode integrity (no iron leaching) and removal efficiency, even after multiple filtration/oxidation treatment cycles, achieving (under steady conditions) DCF and TOC removal 85% and 36%, respectively. This performance is considered satisfactory because the EF process took place under rather unfavorable conditions, such as neutral pH, low dissolved O2 concentration, low electrical conductivity, and presence of natural organic matter and inorganic ions in tap water. Ongoing R&D is aimed at 'filter' development and optimization for practical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Photo-Fenton oxidation of 3-amino-5-methylisoxazole: a by-product from biological breakdown of some pharmaceutical compounds.

PubMed

Souza, Bianca M; Marinho, Belisa A; Moreira, Francisca C; Dezotti, Márcia W C; Boaventura, Rui A R; Vilar, Vítor J P

2017-03-01

The present study aims to assess the removal of 3-amino-5-methylisoxazole (AMI), a recalcitrant by-product resulting from the biological breakdown of some pharmaceuticals, applying a solar photo-Fenton process assisted by ferrioxalate complexes (SPFF) (Fe 3+ /H 2 O 2 /oxalic acid/UVA-Vis) and classical solar photo-Fenton process (SPF) (Fe 2+ /H 2 O 2 /UVA-Vis). The oxidation ability of SPFF was evaluated at different iron/oxalate molar ratios (1:3, 1:6, and 1:9, with [total iron] = 3.58 × 10 -2  mM and [oxalic acid] = 1.07 × 10 -1 , 2.14 × 10 -1 and 3.22 × 10 -1  mM, respectively) and pH values (3.5-6.5), using low iron contents (2.0 mg Fe 3+ L -1 ). Additionally, the use of other organic ligands such as citrate and ethylenediamine-N,N'-disuccinic acid (EDDS) was tested. The oxidation power of the classical SPF was assessed at different pH values (2.8-4.0) using 2.0 mg Fe 2+ per liter. Furthermore, the effect of AMI concentration (2-20 mg L -1 ), presence of inorganic ions (Cl - , SO 4 2- , NO 3 - , HCO 3 - , NH 4 + ), and radical scavengers (sodium azide and D-mannitol) on the SPF method at pH 3.5 was also assessed. Experiments were done using a lab-scale photoreactor with a compound parabolic collector (CPC) under simulated solar radiation. A pilot-scale assay was conducted using the best operation conditions. While at near neutral pH, an iron/oxalate molar ratio of 1:9 led to the removal of 72 % of AMI after 90 min of SPFF, at pH 3.5, an iron/oxalate molar ratio of 1:3 was enough to achieve complete AMI degradation (below the detection limit) after 30 min of reaction. The SPF process at pH 3.5 underwent a slower AMI degradation, reaching total AMI degradation after 40 min of reaction. The scale up of SPF process showed a good reproducibility. Oxalic and oxamic acids were identified as the main low-molecular-weight carboxylic acids detected during the pilot-scale SPF reaction. Graphical abstract ᅟ.

Multistage treatment system for raw leachate from sanitary landfill combining biological nitrification-denitrification/solar photo-Fenton/biological processes, at a scale close to industrial--biodegradability enhancement and evolution profile of trace pollutants.

PubMed

Silva, Tânia F C V; Silva, M Elisabete F; Cunha-Queda, A Cristina; Fonseca, Amélia; Saraiva, Isabel; Sousa, M A; Gonçalves, C; Alpendurada, M F; Boaventura, Rui A R; Vilar, Vítor J P

2013-10-15

A multistage treatment system, at a scale close to the industrial, was designed for the treatment of a mature raw landfill leachate, including: a) an activated sludge biological oxidation (ASBO), under aerobic and anoxic conditions; b) a solar photo-Fenton process, enhancing the bio-treated leachate biodegradability, with and without sludge removal after acidification; and c) a final polishing step, with further ASBO. The raw leachate was characterized by a high concentration of humic substances (HS) (1211 mg CHS/L), representing 39% of the dissolved organic carbon (DOC) content, and a high nitrogen content, mainly in the form of ammonium nitrogen (>3.8 g NH4(+)-N/L). In the first biological oxidation step, a 95% removal of total nitrogen and a 39% mineralization in terms of DOC were achieved, remaining only the recalcitrant fraction, mainly attributed to HS (57% of DOC). Under aerobic conditions, the highest nitrification rate obtained was 8.2 mg NH4(+)-N/h/g of volatile suspended solids (VSS), and under anoxic conditions, the maximum denitrification rate obtained was 5.8 mg (NO2(-)-N + NO3(-)-N)/h/g VSS, with a C/N consumption ratio of 2.4 mg CH3OH/mg (NO2(-)-N + NO3(-)-N). The precipitation of humic acids (37% of HS) after acidification of the bio-treated leachate corresponds to a 96% DOC abatement. The amount of UV energy and H2O2 consumption during the photo-Fenton reaction was 30% higher in the experiment without sludge removal and, consequently, the reaction velocity was 30% lower. The phototreatment process led to the depletion of HS >80%, of low-molecular-weight carboxylate anions >70% and other organic micropollutants, thus resulting in a total biodegradability increase of >70%. The second biological oxidation allowed to obtain a final treated leachate in compliance with legal discharge limits regarding water bodies (with the exception of sulfate ions), considering the experiment without sludge. Finally, the high efficiency of the overall treatment process was further reinforced by the total removal percentages attained for the identified organic trace contaminants (>90%). Copyright © 2013 Elsevier Ltd. All rights reserved.

Enhanced electro-Fenton Mineralization of Acid Orange 7 Using a Carbon Nanotube Fiber Based Cathode

NASA Astrophysics Data System (ADS)

Huong Le, Thi Xuan; Alemán, Belén; Vilatela, Juan J.; Bechelany, Mikhael; Cretin, Marc

2018-02-01

A new cathodic material for electro-Fenton (EF) process was prepared based on a macroscopic fiber (CNTF) made of mm long carbon nanotubes directly spun from the gas phase by floating catalyst CVD, on a carbon fiber (CF) substrate. CNTF@CF electrode is a highly graphitic material combining a high surface area ( 260 m2/g) with high electrical conductivity and electrochemical stability . One kind of azo dye, acid orange 7 (AO7), was used as model bio-refractory pollutant to be treated at CNTF@CF cathode in acidic aqueous medium (pH 3.0). The experimental results pointed out that AO7 and its organic intermediate compounds were totally mineralized by hydroxyl radical generated from Fenton reaction. In fact, 96.7 % of the initial TOC was eliminated in 8h of electrolysis by applying a current of -25 mA and ferrous ions as catalyst at concentration of 0.2 mM. At the same electrolysis time, only 23.7 % of TOC removal found on CF support which proved the high mineralization efficiency of new material thanks to CNTs deposition. The CNTF@CF cathode maintained stable its activity during five experimental cycles of EF set-up. The results indicated that CNTF@CF material could be a potential choice for wastewater treatment containing bio-refractory by electrochemical advanced oxidation processes (EAOPs).

Optimization of the electro-Fenton and solar photoelectro-Fenton treatments of sulfanilic acid solutions using a pre-pilot flow plant by response surface methodology.

PubMed

El-Ghenymy, Abdellatif; Garcia-Segura, Sergi; Rodríguez, Rosa María; Brillas, Enric; El Begrani, Mohamed Soussi; Abdelouahid, Ben Ali

2012-06-30

A central composite rotatable design and response surface methodology were used to optimize the experimental variables of the electro-Fenton (EF) and solar photoelectro-Fenton (SPEF) degradations of 2.5L of sulfanilic acid solutions in 0.05M Na(2)SO(4). Electrolyses were performed with a pre-pilot flow plant containing a Pt/air diffusion reactor generating H(2)O(2). In SPEF, it was coupled with a solar photoreactor under an UV irradiation intensity of ca. 31Wm(-2). Optimum variables of 100mAcm(-2), 0.5mM Fe(2+) and pH 4.0 were determined after 240min of EF and 120min of SPEF. Under these conditions, EF gave 47% of mineralization, whereas SPEF was much more powerful yielding 76% mineralization with 275kWh kg(-1) total organic carbon (TOC) energy consumption and 52% current efficiency. Sulfanilic acid decayed at similar rate in both treatments following a pseudo-first-order kinetics. The final solution treated by EF contained a stable mixture of tartaric, acetic, oxalic and oxamic acids, which form Fe(III) complexes that are not attacked by hydroxyl radicals formed from H(2)O(2) and added Fe(2+). The quick photolysis of these complexes by UV light of sunlight explains the higher oxidation power of SPEF. NH(4)(+) was the main inorganic nitrogen ion released in both processes. Copyright © 2012 Elsevier B.V. All rights reserved.

Pretreatment of lignocellulosic biomass using Fenton chemistry

USDA-ARS?s Scientific Manuscript database

Pretreatment is a necessary step in “biomass to biofuel conversion” due to the recalcitrant nature of lignocellulosic biomass. White-rot fungi utilize peroxidases and hydrogen peroxide (in vivo Fenton chemistry) to degrade lignin. In an attempt to mimic this process, solution phase Fenton chemistry ...

Treatment of TFT-LCD wastewater containing ethanolamine by fluidized-bed Fenton technology.

PubMed

Anotai, Jin; Chen, Chia-Min; Bellotindos, Luzvisminda M; Lu, Ming-Chun

2012-06-01

The objectives of this study are: (1) to determine the effect of pH, initial concentration of Fe(2+) and H(2)O(2) dosage on the removal efficiency of MEA by fluidized-bed Fenton process and Fenton process, (2) to determine the optimal conditions for the degradation of ethanolamine from TFT-LCD wastewater by fluidized-bed Fenton process. In the design of experiment, the Box-Behnken design was used to optimize the operating conditions. A removal efficiency of 98.9% for 5mM MEA was achieved after 2h under optimal conditions of pH3, [Fe(2+)]=5mM and [H(2)O(2)]=60mM. Copyright © 2011 Elsevier Ltd. All rights reserved.

AOX removal from industrial wastewaters using advanced oxidation processes: assessment of a combined chemical-biological oxidation.

PubMed

Luyten, J; Sniegowski, K; Van Eyck, K; Maertens, D; Timmermans, S; Liers, Sven; Braeken, L

2013-01-01

In this paper, the abatement of adsorbable halogenated organic compounds (AOX) from an industrial wastewater containing relatively high chloride concentrations by a combined chemical and biological oxidation is assessed. For chemical oxidation, the O(3)/UV, H(2)O(2)/UV and photo-Fenton processes are evaluated on pilot scale. Biological oxidation is simulated in a 4 h respirometry experiment with periodic aeration. The results show that a selective degradation of AOX with respect to the matrix compounds (expressed as chemical oxygen demand) could be achieved. For O(3)/UV, lowering the ratio of O(3) dosage to UV intensity leads to a better selectivity for AOX. During O(3)-based experiments, the AOX removal is generally less than during the H(2)O(2)-based experiments. However, after biological oxidation, the AOX levels are comparable. For H(2)O(2)/UV, optimal operating parameters for UV and H(2)O(2) dosage are next determined in a second run with another wastewater sample.

Reduction of clarithromycin and sulfamethoxazole-resistant Enterococcus by pilot-scale solar-driven Fenton oxidation.

PubMed

Karaolia, Popi; Michael, Irene; García-Fernández, Irene; Agüera, Ana; Malato, Sixto; Fernández-Ibáñez, Pilar; Fatta-Kassinos, Despo

2014-01-15

The presence of pathogenic antibiotic-resistant bacteria in aquatic environments has become a health threat in the last few years. Their presence has increased due to the presence of antibiotics in wastewater effluents, which are not efficiently removed by conventional wastewater treatments. As a result there is a need to study the possible ways of removal of the mixtures of antibiotics present in wastewater effluents and the antibiotic-resistant bacteria, which may also spread the antibiotic resistance genes to other bacterial populations. In this study the degradation of a mixture of antibiotics i.e. sulfamethoxazole and clarithromycin, the disinfection of total enterococci and the removal of those resistant to: a) sulfamethoxazole, b) clarithromycin and c) to both antibiotics have been examined, along with the toxicity of the whole effluent mixture after treatment to the luminescent aquatic bacterium Vibrio fischeri. Solar Fenton treatment (natural solar driven oxidation) using Fenton reagent doses of 50 mg L(-1) of hydrogen peroxide and 5 mg L(-1) of Fe(3+) in a pilot-scale compound parabolic collector plant was used to examine the disinfection and antibiotic resistance removal efficiency in different aqueous matrices, namely distilled water, simulated and real wastewater effluents. There was a faster complete removal of enterococci and of antibiotics in all aqueous matrices by applying solar Fenton when compared to photolytic treatment of the matrices. Sulfamethoxazole was more efficiently degraded than clarithromycin in all three aqueous matrices (95% removal of sulfamethoxazole and 70% removal of clarithromycin in real wastewater). The antibiotic resistance of enterococci towards both antibiotics exhibited a 5-log reduction with solar Fenton in real wastewater effluent. Also after solar Fenton treatment, there were 10 times more antibiotic-resistant enterococci in the presence of sulfamethoxazole than in the presence of clarithromycin. Finally, the toxicity of the treated wastewater to V. fischeri remained very low throughout the treatment time. © 2013.

Photochemical-biological treatment of a real industrial biorecalcitrant wastewater containing 5-amino-6-methyl-2-benzimidazolone.

PubMed

Sarria, V; Parra, S; Invernizzi, M; Peringer, P; Pulgarin, C

2001-01-01

5-amino-6-methyl-2-benzimidazolone (AMBI), used in the manufacture of dyes, was characterised as a biorecalcitrant compound by means of different biodegradability tests. In order to enhance the biodegradability of this important pollutant, the application of Advanced Oxidation Process (AOPs) as a pretreatment was explored. Some experiments were addressed to find the most efficient AOP. The systems H2O2/hv, TiO2/H2O2/hv, Fe3+/hv, Fe3+/H2O2 and Fe3+/H2O2/hv were compared. The photo-Fenton system was the most efficient and the optimal conditions (AMBI, Fe3+, H2O2 concentrations) for the degradation of AMBI were found. During the photo-Fenton degradation, experiments were also made to obtain information concerning the evolution of: (a) organic carbon and initial compound concentration; (b) the oxidation state; (c) the toxicity; (d) the biodegradability; and (e) the chemical nature of the intermediates. These analyses show that the solution resulting from the treatment of AMBI is biologically compatible and complete mineralisation can be performed by biological means. A combined photochemical (Fenton) and biological flow reactor for the degradation of AMBI was successfully operated in continuous mode at laboratory scale. 100% of the initial concentration of AMBI and 80.3% of Dissolved Organic Carbon (DOC) were removed in 3.5 hours of total residence time. Finally, some field experiments under direct sunlight carried out at the Plataforma Solar de Almeria, Spain, demonstrated that this solar catalytic system is an effective treatment for this kind of industrial wastewater.

Analogies and differences among bacterial and viral disinfection by the photo-Fenton process at neutral pH: a mini review.

PubMed

Giannakis, Stefanos

2017-12-19

Over the last years, the photo-Fenton process has been established as an effective, green alternative to chemical disinfection of waters and wastewaters. Microorganisms' inactivation is the latest success story in the application of this process at near-neutral pH, albeit without clearly elucidated inactivation mechanisms. In this review, the main pathways of the combined photo-Fenton process against the most frequent pathogen models (Escherichia coli for bacteria and MS2 bacteriophage for viruses) are analyzed. Firstly, the action of solar light is described and the specific inactivation mechanisms in bacteria (internal photo-Fenton) and viruses (genome damage) are presented. The contribution of the external pathways due to the potential presence of organic matter in generating reactive oxygen species (ROS) and their effects on microorganism inactivation are discussed. Afterwards, the effects of the gradual addition of Fe and H 2 O 2 are assessed and the differences among bacterial and viral inactivation are highlighted. As a final step, the simultaneous addition of both reagents induces the photo-Fenton in the bulk, focusing on the differences induced by the homogeneous or heterogeneous fraction of the process and the variation among the two respective targets. This work exploits the accumulated evidence on the mechanisms of bacterial inactivation and the scarce ones towards viral targets, aiming to bridge this knowledge gap and make possible the further application of the photo-Fenton process in the field of water/wastewater treatment.

Remediation of a winery wastewater combining aerobic biological oxidation and electrochemical advanced oxidation processes.

PubMed

Moreira, Francisca C; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

2015-05-15

Apart from a high biodegradable fraction consisting of organic acids, sugars and alcohols, winery wastewaters exhibit a recalcitrant fraction containing high-molecular-weight compounds as polyphenols, tannins and lignins. In this context, a winery wastewater was firstly subjected to a biological oxidation to mineralize the biodegradable fraction and afterwards an electrochemical advanced oxidation process (EAOP) was applied in order to mineralize the refractory molecules or transform them into simpler ones that can be further biodegraded. The biological oxidation led to above 97% removals of dissolved organic carbon (DOC), chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5), but was inefficient on the degradation of a bioresistant fraction corresponding to 130 mg L(-1) of DOC, 380 mg O2 L(-1) of COD and 8.2 mg caffeic acid equivalent L(-1) of total dissolved polyphenols. Various EAOPs such as anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF), UVA photoelectro-Fenton (PEF) and solar PEF (SPEF) were then applied to the recalcitrant effluent fraction using a 2.2 L lab-scale flow plant containing an electrochemical cell equipped with a boron-doped diamond (BDD) anode and a carbon-PTFE air-diffusion cathode and coupled to a photoreactor with compound parabolic collectors (CPCs). The influence of initial Fe(2+) concentration and current density on the PEF process was evaluated. The relative oxidative ability of EAOPs increased in the order AO-H2O2 < EF < PEF ≤ SPEF. The SPEF process using an initial Fe(2+) concentration of 35 mg L(-1), current density of 25 mA cm(-2), pH of 2.8 and 25 °C reached removals of 86% on DOC and 68% on COD after 240 min, regarding the biologically treated effluent, along with energy consumptions of 45 kWh (kg DOC)(-1) and 5.1 kWh m(-3). After this coupled treatment, color, odor, COD, BOD5, NH4(+), NO3(-) and SO4(2-) parameters complied with the legislation targets and, in addition, a total dissolved polyphenols content of 0.35 mg caffeic acid equivalent L(-1) was found. Respirometry tests revealed low biodegradability enhancement along the SPEF process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Advanced oxidation process-mediated removal of pharmaceuticals from water: A review.

PubMed

Kanakaraju, Devagi; Glass, Beverley D; Oelgemöller, Michael

2018-08-01

Pharmaceuticals, which are frequently detected in natural and wastewater bodies as well as drinking water have attracted considerable attention, because they do not readily biodegrade and may persist and remain toxic. As a result, pharmaceutical residues pose on-going and potential health and environmental risks. To tackle these emerging contaminants, advanced oxidation processes (AOPs) such as photo-Fenton, sonolysis, electrochemical oxidation, radiation and ozonation etc. have been applied to remove pharmaceuticals. These processes utilize the high reactivity of hydroxyl radicals to progressively oxidize organic compounds to innocuous products. This review provides an overview of the findings from recent studies, which have applied AOPs to degrade pharmaceutical compounds. Included is a discussion that links various factors of TiO 2 -mediated photocatalytic treatment to its effectiveness in degrading pharmaceutical residues. This review furthermore highlights the success of AOPs in the removal of pharmaceuticals from different water matrices and recommendations for future studies are outlined. Copyright © 2018 Elsevier Ltd. All rights reserved.

Catalase-Modulated Heterogeneous Fenton Reaction for Selective Cancer Cell Eradication: SnFe2O4 Nanocrystals as an Effective Reagent for Treating Lung Cancer Cells.

PubMed

Lee, Kuan-Ting; Lu, Yu-Jen; Mi, Fwu-Long; Burnouf, Thierry; Wei, Yi-Ting; Chiu, Shao-Chieh; Chuang, Er-Yuan; Lu, Shih-Yuan

2017-01-18

Heterogeneous Fenton reactions have been proven to be an effective and promising selective cancer cell treatment method. The key working mechanism for this method to achieve the critical therapeutic selectivity however remains unclear. In this study, we proposed and demonstrated for the first time the critical role played by catalase in realizing the therapeutic selectivity for the heterogeneous Fenton reaction-driven cancer cell treatment. The heterogeneous Fenton reaction, with the lattice ferric ions of the solid catalyst capable of converting H 2 O 2 to highly reactive hydroxyl radicals, can effectively eradicate cancer cells. In this study, SnFe 2 O 4 nanocrystals, a recently discovered outstanding heterogeneous Fenton catalyst, were applied for selective killing of lung cancer cells. The SnFe 2 O 4 nanocrystals, internalized into the cancer cells, can effectively convert endogenous H 2 O 2 into highly reactive hydroxyl radicals to invoke an intensive cytotoxic effect on the cancer cells. On the other hand, catalase, present at a significantly higher concentration in normal cells than in cancer cells, remarkably can impede the apoptotic cell death induced by the internalized SnFe 2 O 4 nanocrystals. According to the results obtained from the in vitro cytotoxicity study, the relevant oxidative attacks were effectively suppressed by the presence of normal physiological levels of catalase. The SnFe 2 O 4 nanocrystals were thus proved to effect apoptotic cancer cell death through the heterogeneous Fenton reaction and were benign to cells possessing normal physiological levels of catalase. The catalase modulation of the involved heterogeneous Fenton reaction plays the key role in achieving selective cancer cell eradication for the heterogeneous Fenton reaction-driven cancer cell treatment.

Polymeric micellar nanoplatforms for Fenton reaction as a new class of antibacterial agents.

PubMed

Park, Seong-Cheol; Kim, Nam-Hong; Yang, Wonseok; Nah, Jae-Woon; Jang, Mi-Kyeong; Lee, Dongwon

2016-01-10

Reactive oxygen species (ROS) produced by host phagocytes exert antibacterial action against a variety of pathogens and ROS-induced oxidative stress is the governing mechanism for the antibacterial activity of major bactericidal antibiotics. In particular, hydroxyl radical is a strong and nonselective oxidant which can damage biomolecules such as DNA, proteins and lipids. Ferrous ion is known to convert mild oxidant hydrogen peroxide (H2O2) into highly reactive and toxic hydroxyl radicals, referred to as Fenton reaction. Herein, we report a new class of antibacterial agents based on Fenton reaction-performing nanostructures, composed of H2O2-generating polymer (PCAE) and iron-containing ferrocene. Amphiphilic PCAE was designed to incorporate H2O2-generating cinnamaldehyde through acid-cleavable linkages and self-assemble to form thermodynamically stable micelles which could encapsulate ferrocene in their hydrophobic core. All the experiments in vitro display that ferrocene-loaded PCAE micelles produce hydroxyl radicals to kill Escherichia coli and Pseudomonas aeruginosa through membrane damages. Intraperitoneally injected ferrocene-loaded PCAE micelles significantly reduced the lung damages and therefore increased the survival rate of mice infected with drug resistant P. aeruginosa. Given their potent antibacterial activity, ferrocene-loaded PCAE micelles hold great potential as a new class of ROS-manipulating antibacterial agents. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of Fenton pre-oxidation on mobilization of nutrients and efficient subsequent bioremediation of crude oil-contaminated soil.

PubMed

Xu, Jinlan; Kong, Fanxing; Song, Shaohua; Cao, Qianqian; Huang, Tinglin; Cui, Yiwei

2017-08-01

Fenton pre-oxidation and a subsequent bioremediation phase of 80 days were used to investigate the importance of matching concentration of residual indigenous bacteria and nutrient levels on subsequent bioremediation of crude oil. Experiments were performed using either high (>10 7.7 ± 0.2  CFU/g soil) or low (<10 5.9 ± 0.1  CFU/g soil) concentrations of bacteria and three different nutrient levels: enough (C/N > 9.8), moderate (C/N:5-9.8), and lacking nutrient level (C/N < 5) conditions. Weak Fenton pre-oxidation (225 mM H 2 O 2 and 2.9 mM Fe 2+ ) resulted in highly matching between nutrient level and the population of residual indigenous bacteria. Up to 53% of total petroleum hydrocarbon (TPH) and 58% of main hydrocarbon (C 15 C 25 , during the first 10 days) were removed from the soil. Under matching conditions, the activity of indigenous bacteria and nutrient mobilization were enhanced, promoting the bioremediation of crude oil. In addition, the biodegradation of long chain molecules (C 26 C 30 ) required a high level of NH 4 + -N. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation of applicability of Electro-Fenton method for the mineralization of naphthol blue black in water.

PubMed

Özcan, Ayça Atılır; Özcan, Ali

2018-07-01

In this study, mineralization and color removal performance of electro-Fenton method were examined in water containing naphthol blue black (NBB), a diazo dye. NBB was totally converted to intermediate species in a 15-min electrolysis at 60 mA, but complete de-colorization took 180 min. A very high oxidation rate constant ((3.35 ± 0.21) x 10 10  M -1 s -1 ) was obtained for NBB, showing its high reactivity towards hydroxyl radicals. A very high total organic carbon (TOC) removal value (45.23 mg L -1 ) was obtained in the first 60 min of the electro-Fenton treatment of an aqueous solution of NBB (0.25 mM) at 300 mA, indicating the mineralization efficiency of the electro-Fenton method. Mineralization current efficiency values obtained at 300 mA gradually decreased from 24.18% to 4.47% with the electrolysis time, indicating the presence of highly parasitic reactions. Gas chromatography-mass spectrometry analyses revealed that the cleavage of azo bonds of NBB led to formation of different aromatic and aliphatic oxidation intermediates. Ion chromatography analysis showed that ammonium, nitrate and sulfate were the mineralization end-products. The concentration of sulfate ion reached to its quantitative value at the 4th h of electrolysis. On the other hand, the total concentration of ammonium and nitrate ions reached to only 61% of the stoichiometric amount of initial nitrogen after a 7 h electrolysis. Finally, it can be said that the electro-Fenton method is a suitable and efficient method for the removal of NBB and its intermediates from water. Copyright © 2018 Elsevier Ltd. All rights reserved.

Treatment of antibiotic fermentation wastewater by combined polyferric sulfate coagulation, Fenton and sedimentation process.

PubMed

Xing, Zi-Peng; Sun, De-Zhi

2009-09-15

Attempts were made in this study to examine the combined polyferric sulfate (PFS) coagulation, Fenton and sedimentation process for treatment of non-degradable antibiotic fermentation wastewater. The experimental results indicated that 66.6% of color and 72.4% of chemical oxygen demand (COD) were removed under the optimum conditions of PFS dosage 200mg/L and pH 4.0. In addition, optimal parameters of Fenton process were determined to be 150 mg/L of H(2)O(2) dosage, 120 mg/L of FeSO(4) and 1h of reaction time. When Fenton treated effluent was controlled at pH 7.0, the pollutants could be further removed by sedimentation process. The overall color, COD and suspended solids (SS) removal reached 97.3%, 96.9% and 86.7% under selected conditions, respectively. Thus this study might offer an effective way for wastewater treatment of antibiotics manufacturer and pharmaceutical industry.

A Fe3O4/FeAl2O4 composite coating via plasma electrolytic oxidation on Q235 carbon steel for Fenton-like degradation of phenol.

PubMed

Wang, Jiankang; Yao, Zhongping; Yang, Min; Wang, Yajing; Xia, Qixing; Jiang, Zhaohua

2016-08-01

The Fe3O4/FeAl2O4 composite coatings were successfully fabricated on Q235 carbon steel by plasma electrolytic oxidation technique and used to degrade phenol by Fenton-like system. XRD, SEM, and XPS indicated that Fe3O4 and FeAl2O4 composite coating had a hierarchical porous structure. The effects of various parameters such as pH, phenol concentration, and H2O2 dosage on catalytic activity were investigated. The results indicated that with increasing of pH and phenol content, the phenol degradation efficiency was reduced significantly. However, the degradation rate was improved with the addition of H2O2, but dropped with further increasing of H2O2. Moreover, 100 % removal efficiency with 35 mg/L phenol was obtained within 60 min at 303 K and pH 4.0 with 6.0 mmol/L H2O2 on 6-cm(2) iron oxide coating. The degradation process consisted of induction period and rapid degradation period; both of them followed pseudo-first-order reaction. Hydroxyl radicals were the mainly oxidizing species during phenol degradation by using n-butanol as hydroxyl radical scavenger. Based on Fe leaching and the reaction kinetics, a possible phenol degradation mechanism was proposed. The catalyst exhibited excellent stability.

Synergetic pretreatment of waste activated sludge by hydrodynamic cavitation combined with Fenton reaction for enhanced dewatering.

PubMed

Cai, Meiqiang; Hu, Jianqiang; Lian, Guanghu; Xiao, Ruiyang; Song, Zhijun; Jin, Micong; Dong, Chunying; Wang, Quanyuan; Luo, Dewen; Wei, Zongsu

2018-04-01

The dewatering of waste activated sludge by integrated hydrodynamic cavitation (HC) and Fenton reaction was explored in this study. We first investigated the effects of initial pH, sludge concentration, flow rate, and H 2 O 2 concentration on the sludge dewaterability represented by water content, capillary suction time and specific resistance to filtration. The results of dewatering tests showed that acidic pH and low sludge concentration were favorable to improve dewatering performance in the HC/Fenton system, whereas optimal flow rate and H 2 O 2 concentration applied depended on the system operation. To reveal the synergism of HC/Fenton treatment, a suite of analysis were implemented: three-dimensional excitation emission matrix (3-DEEM) spectra of extracellular polymeric substances (EPS) such as proteins and polysaccharides, zeta potential and particle size of sludge flocs, and SEM/TEM imaging of sludge morphology. The characterization results indicate a three-step mechanism, namely HC fracture of different EPS in sludge flocs, Fenton oxidation of the released EPS, and Fe(III) re-flocculation, that is responsible for the synergistically enhanced sludge dewatering. Results of current study provide a basis to improve our understanding on the sludge dewatering performance by HC/Fenton treatment and possible scale-up of the technology for use in wastewater treatment plants. Copyright © 2017 Elsevier B.V. All rights reserved.

Degradation of bisphenol A in water by the heterogeneous photo-Fenton.

PubMed

Jiang, Chuanrui; Xu, Zhencheng; Guo, Qingwei; Zhuo, Qiongfang

2014-01-01

Bisphenol A (BPA) is a kind of a controversial endocrine disruptor, and is ubiquitous in environment. The degradation of BPA with the heterogeneous photo-Fenton system was demonstrated in this study. The Fe-Y molecular sieve catalyst was prepared with the ion exchange method, and it was characterized by X-ray radiation diffraction (XRD). The effects ofpH, initial concentration of H2O2, initial BPA concentration, and irradiation intensity on the degradation of BPA were investigated. The service life and iron solubility of catalyst were also tested. XRD test shows that the major phase of the Fe-Y catalyst was Fe2O3. The method of heterogeneous photo-Fenton with Fe-Y catalyst was superior to photolysis, photo-oxidation with only hydrogen, heterogeneous Fenton, and homogeneous photo-Fenton approaches. pH value had no obvious effects on BPA degradation over the range of 2.2-7.2. The initial concentration of H2O2 had an optimal value of 20 x 10(-4) mol/L. The decrease in initial concentration of BPA was favourable for degradation. The intensity of ultraviolet irradiation has no obvious effect on the BPA removal. The stability tests indicated that the Fe-Y catalyst can be reused and iron solubility concentration ranged from NA to 0.0062 mg/L. Based on the results, the heterogeneous photo-Fenton treatment is the available method for the degradation of BPA.

Iron-chelating agents never suppress Fenton reaction but participate in quenching spin-trapped radicals.

PubMed

Li, Linxiang; Abe, Yoshihiro; Kanagawa, Kiyotada; Shoji, Tomoko; Mashino, Tadahiko; Mochizuki, Masataka; Tanaka, Miho; Miyata, Naoki

2007-09-19

Hydroxyl radical formation by Fenton reaction in the presence of an iron-chelating agent such as EDTA was traced by two different assay methods; an electron spin resonance (ESR) spin-trapping method with 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and high Performance liquid chromatography (HPLC)-fluorescence detection with terephthalic acid (TPA), a fluorescent probe for hydroxyl radicals. From the ESR spin-trapping measurement, it was observed that EDTA seemed to suppress hydroxyl radical formation with the increase of its concentration. On the other hand, hydroxyl radical formation by Fenton reaction was not affected by EDTA monitored by HPLC assay. Similar inconsistent effects of other iron-chelating agents such as nitrylotriacetic acid (NTA), diethylenetriamine penta acetic acid (DTPA), oxalate and citrate were also observed. On the addition of EDTA solution to the reaction mixture 10 min after the Fenton reaction started, when hydroxyl radical formation should have almost ceased but the ESR signal of DMPO-OH radicals could be detected, it was observed that the DMPO-OH* signal disappeared rapidly. With the simultaneous addition of Fe(II) solution and EDTA after the Fenton reaction ceased, the DMPO-OH* signal disappeared more rapidly. The results indicated that these chelating agents should enhance the quenching of [DMPO-OH]* radicals by Fe(II), but they did not suppress Fenton reaction by forming chelates with iron ions.

Recent advances in application of UV light-emitting diodes for degrading organic pollutants in water through advanced oxidation processes: A review.

PubMed

Matafonova, Galina; Batoev, Valeriy

2018-04-01

Over the last decade, ultraviolet light-emitting diodes (UV LEDs) have attracted considerable attention as alternative mercury-free UV sources for water treatment purposes. This review is a comprehensive analysis of data reported in recent years (mostly, post 2014) on the application of UV LED-induced advanced oxidation processes (AOPs) to degrade organic pollutants, primarily dyes, phenols, pharmaceuticals, insecticides, estrogens and cyanotoxins, in aqueous media. Heterogeneous TiO 2 -based photocatalysis in lab grade water using UVA LEDs is the most frequently applied method for treating organic contaminants. The effects of controlled periodic illumination, different TiO 2 -based nanostructures and reactor types on degradation kinetics and mineralization are discussed. UVB and UVC LEDs have been used for photo-Fenton, photo-Fenton-like and UV/H 2 O 2 treatment of pollutants, primarily, in model aqueous solutions. Notably, UV LED-activated persulfate/peroxymonosulfate processes were capable of providing degradation in DOC-containing waters. Wall-plug efficiency, energy-efficiency of UV LEDs and the energy requirements in terms of Electrical Energy per Order (E EO ) are discussed and compared. Despite the overall high degradation efficiency of the UV LED-based AOPs, practical implementation is still limited and at lab scale. More research on real water matrices at more environmentally relevant concentrations, as well as an estimation of energy requirements providing fluence-based kinetic data are required. Copyright © 2018 Elsevier Ltd. All rights reserved.

Disinfection of wastewater effluents with the Fenton-like process induced by electromagnetic fields.

PubMed

Rodríguez-Chueca, J; Mediano, A; Ormad, M P; Mosteo, R; Ovelleiro, J L

2014-09-01

This research work is focused on the application and assessment of effectiveness of the Fenton-like processes induced by radiofrequency for the inactivation of faecal bacteria (Escherichia coli and Enterococcus sp.) present in treated urban wastewater effluents. Fenton processes were carried out at near neutral pH (pH 5) with different iron sources, such as iron salts (ferric chloride, 5, 50 and 100 mg/L Fe(3+)), magnetite (1 g/L) and clay (80 g/L), hydrogen peroxide (25 mg/L) and in absence and presence of radiofrequency. Two different electromagnetic field intensities (1.57 and 3.68 kA/m) were used in Fenton processes induced by radiofrequency. Different agents used in the Fenton processes induced by electromagnetic fields (iron source, hydrogen peroxide and RF) were analyzed individually and in combination under the same experimental conditions. First assays of ferromagnetic material/H2O2/radiofrequency processes achieved promising results in terms of bacterial inactivation. For instance, Fe(3+)/H2O2/Radiofrequency achieved a maximum level of E. coli inactivation of 3.55 log after 10 min of treatment. These results are higher than those obtained in absence of radiofrequency. The thermal activation of iron atoms allows the Fenton reaction to intensify, increasing the final yield of the treatment. On the other hand, different behavior was observed in the inactivation of E. coli and Enterococcus sp. due to the structural differences between Gram-negative and Gram-positive bacteria. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cold Incineration of Chlorophenols in Aqueous Solution by Advanced Electrochemical Process Electro-Fenton. Effect of Number and Position of Chlorine Atoms on the Degradation Kinetics

NASA Astrophysics Data System (ADS)

Oturan, Nihal; Panizza, Marco; Oturan, Mehmet A.

2009-09-01

This study reports the kinetics of the degradation of several chlorophenols (CPs), such as monochlorophenols (2-chlorophenol and 4-chlorophenol), dichlorophenols (2,4-dichlorophenol and 2,6- dichlorophenol), trichlorophenols (2,3,5- trichlorophenol and 2,4,5-trichlorophenol), 2,3,5,6-tetrachlorophenol, and pentachlorophenol, by the electro-Fenton process using a carbon felt cathode and a Pt anode. The effect of number and the position of the chlorine atoms in the aromatic ring on the oxidative degradation rate was evaluated and discussed. The oxidation reaction of all the CPs with hydroxyl radicals evidenced a pseudo-first-order kinetics and the rate constant decreased with increasing the number of chlorine atoms. The absolute rate constant of second-order reaction kinetics between CPs and •OH was determined by the competition kinetics method in the range of (3.56-7.75) × 109 M-1 s-1 and follows the same sequence of the apparent rate constants. The mineralization of several CPs and of a mixture of all CPs under study was monitored by the total organic carbon (TOC) removal and the chlorine release during mineralization was followed by ion chromatography. Our results demonstrated that more chlorinated phenols are more difficult to mineralize; however for all the tested CPs, almost quantitative release of chloride ions was obtained after 6 h of treatment.

Phytoremediation and innovative strategies for specialized remedial actions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alleman, B.C.; Leeson, A.

1999-11-01

Phytoremediation is a site remediation strategy whose time seems to have come in the past few years, with field implementations taking place in a host of applications. From laboratory studies on plant uptake to full-scale phytoremediation treatment strategies, this volume covers the use of plants to treat contaminants such as hydrocarbons, metals, pesticides, perchlorate, and chlorinated solvents. In addition to the phytoremediation studies, this volume also covers specialized remediation approaches such as sequential anaerobic/aerobic in situ treatment, membrane bioreactors, and Fenton`s reagent oxidation.

Phytoremediation and innovative strategies for specialized remedial applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alleman, B.C.; Leeson, A.

1999-10-01

Phytoremediation is a site remediation strategy whose time seems to have come in the past few years, with field implementations taking place in a host of applications. From laboratory studies on plant uptake to full-scale phytoremediation treatment strategies, this volume covers the use of plants to treat contaminants such as hydrocarbons, metals, pesticides, perchlorate, and chlorinated solvents. In addition to the phytoremediation studies, this volume also covers specialized remediation approaches such as sequential anaerobic/aerobic in situ treatment, membrane bioreactors, and Fenton`s reagent oxidation.

Phenol wastewater remediation: advanced oxidation processes coupled to a biological treatment.

PubMed

Rubalcaba, A; Suárez-Ojeda, M E; Stüber, F; Fortuny, A; Bengoa, C; Metcalfe, I; Font, J; Carrera, J; Fabregat, A

2007-01-01

Nowadays, there are increasingly stringent regulations requiring more and more treatment of industrial effluents to generate product waters which could be easily reused or disposed of to the environment without any harmful effects. Therefore, different advanced oxidation processes were investigated as suitable precursors for the biological treatment of industrial effluents containing phenol. Wet air oxidation and Fenton process were tested batch wise, while catalytic wet air oxidation and H2O2-promoted catalytic wet air oxidation processes were studied in a trickle bed reactor, the last two using over activated carbon as catalyst. Effluent characterisation was made by means of substrate conversion (using high liquid performance chromatography), chemical oxygen demand and total organic carbon. Biodegradation parameters (i.e. maximum oxygen uptake rate and oxygen consumption) were obtained from respirometric tests using activated sludge from an urban biological wastewater treatment plant (WWTP). The main goal was to find the proper conditions in terms of biodegradability enhancement, so that these phenolic effluents could be successfully treated in an urban biological WWTP. Results show promising research ways for the development of efficient coupled processes for the treatment of wastewater containing toxic or biologically non-degradable compounds.

The application of advanced oxidation technologies to the treatment of effluents from the pulp and paper industry: a review.

PubMed

Hermosilla, Daphne; Merayo, Noemí; Gascó, Antonio; Blanco, Ángeles

2015-01-01

The paper industry is adopting zero liquid effluent technologies to reduce freshwater use and meet environmental regulations, which implies closure of water circuits and the progressive accumulation of pollutants that must be removed before water reuse and final wastewater discharge. The traditional water treatment technologies that are used in paper mills (such as dissolved air flotation or biological treatment) are not able to remove recalcitrant contaminants. Therefore, advanced water treatment technologies, such as advanced oxidation processes (AOPs), are being included in industrial wastewater treatment chains aiming to either improve water biodegradability or its final quality. A comprehensive review of the current state of the art regarding the use of AOPs for the treatment of the organic load of effluents from the paper industry is herein addressed considering mature and emerging treatments for a sustainable water use in this sector. Wastewater composition, which is highly dependent on the raw materials being used in the mills, the selected AOP itself, and its combination with other technologies, will determine the viability of the treatment. In general, all AOPs have been reported to achieve good organic removal efficiencies (COD removal >40%, and about an extra 20% if AOPs are combined with biological stages). Particularly, ozonation has been the most extensively reported and successfully implemented AOP at an industrial scale for effluent treatment or reuse within pulp and paper mills, although Fenton processes (photo-Fenton particularly) have actually addressed better oxidative results (COD removal ≈ 65-75%) at a lab scale, but still need further development at a large scale.

Lignocellulosic polysaccharides and lignin degradation by wood decay fungi: the relevance of nonenzymatic Fenton-based reactions.

PubMed

Arantes, Valdeir; Milagres, Adriane M F; Filley, Timothy R; Goodell, Barry

2011-04-01

The brown rot fungus Wolfiporia cocos and the selective white rot fungus Perenniporia medulla-panis produce peptides and phenolate-derivative compounds as low molecular weight Fe³+-reductants. Phenolates were the major compounds with Fe³+-reducing activity in both fungi and displayed Fe³+-reducing activity at pH 2.0 and 4.5 in the absence and presence of oxalic acid. The chemical structures of these compounds were identified. Together with Fe³+ and H₂O₂ (mediated Fenton reaction) they produced oxygen radicals that oxidized lignocellulosic polysaccharides and lignin extensively in vitro under conditions similar to those found in vivo. These results indicate that, in addition to the extensively studied Gloeophyllum trabeum--a model brown rot fungus--other brown rot fungi as well as selective white rot fungi, possess the means to promote Fenton chemistry to degrade cellulose and hemicellulose, and to modify lignin. Moreover, new information is provided, particularly regarding how lignin is attacked, and either repolymerized or solubilized depending on the type of fungal attack, and suggests a new pathway for selective white rot degradation of wood. The importance of Fenton reactions mediated by phenolates operating separately or synergistically with carbohydrate-degrading enzymes in brown rot fungi, and lignin-modifying enzymes in white rot fungi is discussed. This research improves our understanding of natural processes in carbon cycling in the environment, which may enable the exploration of novel methods for bioconversion of lignocellulose in the production of biofuels or polymers, in addition to the development of new and better ways to protect wood from degradation by microorganisms.

HANDBOOK ON ADVANCED PHOTOCHEMICAL OXIDATION ...

EPA Pesticide Factsheets

This handbook summarizes commercial-scale system performance and cost data for advanced photochemical oxidation (APO) treatment of contaminated water, air, and solids. Similar information from pilot- and bench-scale evaluations of APO processes is also included to supplement the commercial-scale data. Performance and cost data is summarized for various APO processes, including vacuum ultraviolet (VUV) photolysis, ultraviolet (UV)/oxidation, photo-Fenton, and dye- or semiconductor-sensitized APO processes. This handbook is intended to assist engineering practitioners in evaluating the applicability of APO processes and in selecting one or more such processes for site-specific evaluation.APO has been shown to be effective in treating contaminated water and air. Regarding contaminated water treatment, UV/oxidation has been evaluated for the most contaminants, while VUV photolysis has been evaluated for the fewest. Regarding contaminated air treatment, the sensitized APO processes have been evaluated for the most contaminants, while VUV photolysis has been evaluated for the fewest.APO processes for treating contaminated solids generally involve treatment of contaminated slurry or leachate generated using an extraction process such as soil washing. APO has been shown to be effective in treating contaminated solids, primarily at the bench-scale level. Information

Decolorization and degradation of reactive yellow HF aqueous solutions by electrochemical advanced oxidation processes.

PubMed

Bedolla-Guzman, A; Feria-Reyes, R; Gutierrez-Granados, S; Peralta-Hernández, Juan M

2017-05-01

Textile manufacturing is the one responsible for water bodies' contamination through the discharge of colored wastes. This work presents the study of reactive yellow HF (RYHF) dye degradation under two different electrochemical advanced oxidation processes (EAOP), namely anodic oxidation (AO) and electro-Fenton (EF)/boron-doped diamond (BDD) process. For the AO, 100 and 300 mg/L solutions using Pt and BDD as anodes in a 100 mL stirred tank cell were used, with a supporting electrolyte of 0.05 mol/L of Na 2 SO 4 at pH 3 under 30 and 50 mA/cm 2 current density. The EF/BDD process was carried out in a flow reactor at 4 and 7 L/min to degrade 100, 200, and 300 mg/L RYHF solutions under 50 and 80 mA/cm 2 . UV-Vis determinations were used for decolorization evaluation, while high-performance liquid chromatography (HPLC) method provided information on dye degradation rate.

General aspects of metal toxicity.

PubMed

Kozlowski, H; Kolkowska, P; Watly, J; Krzywoszynska, K; Potocki, S

2014-01-01

This review is focused on the general mechanisms of metal toxicity in humans. The possible and mainly confirmed mechanisms of their action are discussed. The metals are divided into four groups due to their toxic effects. First group comprises of metal ions acting as Fenton reaction catalyst mainly iron and copper. These types of metal ions participate in generation of the reactive oxygen species. Metals such as nickel, cadmium and chromium are considered as carcinogenic agents. Aluminum, lead and tin are involved in neurotoxicity. The representative of the last group is mercury, which may be considered as a generally toxic metal. Fenton reaction is a naturally occurring process producing most active oxygen species, hydroxyl radical: Fe(2+) + He2O2 ↔ Fe(3+) + OH(-) + OH(•) It is able to oxidize most of the biomolecules including DNA, proteins, lipids etc. The effect of toxicity depends on the damage of molecules i.e. production site of the hydroxyl radical. Chromium toxicity depends critically on its oxidation state. The most hazardous seems to be Cr(6+) (chromates) which are one of the strongest inorganic carcinogenic agents. Cr(6+) species act also as oxidative agents damaging among other nucleic acids. Redox inactive Al(3+), Cd(2+) or Hg(2+) may interfere with biology of other metal ions e.g. by occupying metal binding sites in biomolecules. All these aspects will be discussed in the review.

Solar photo-Fenton using peroxymonosulfate for organic micropollutants removal from domestic wastewater: comparison with heterogeneous TiO₂ photocatalysis.

PubMed

Ahmed, Moussa Mahdi; Brienza, Monica; Goetz, Vincent; Chiron, Serge

2014-12-01

This work aims at decontaminating biologically treated domestic wastewater effluents from organic micropollutants by sulfate radical based (SO4(-)) homogeneous photo-Fenton involving peroxymonosulfate as an oxidant, ferrous iron (Fe(II)) as a catalyst and simulated solar irradiation as a light source. This oxidative system was evaluated by using several probe compounds belonging to pesticides (bifenthrin, mesotrione and clothianidin) and pharmaceuticals (diclofenac, sulfamethoxazole and carbamazepine) classes and its kinetic efficiency was compared to that to the well known UV-Vis/TiO2 heterogeneous photocatalysis. Except for carbamazepine, apparent kinetic rate constants were always 10 times higher in PMS/Fe(II)/UV-Vis than in TiO2/UV-Vis system and more than 70% of total organic carbon abatement was reached in less than one hour treatment. Hydroxyl radical (OH) and SO4(-) reactivity was investigated using mesotrione as a probe compound through by-products identification by liquid chromatography-high resolution-mass spectrometry and transformation pathways elucidation. In addition to two OH based transformation pathways, a specific SO4(-) transformation pathway which first involved degradation through one electron transfer oxidation processes followed by decarboxylation were probably responsible for mesotrione degradation kinetic improvement upon UV-Vis/PMS/Fe(II) system in comparison to UVVis/TiO2 system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of low-purity Fenton reagents on toxicity of textile dyeing effluent to Daphnia magna.

PubMed

Na, Joorim; Yoo, Jisu; Nam, Gwiwoong; Jung, Jinho

2017-09-20

This study aimed to identify the source of toxicity in textile dyeing effluent collected from February to July 2016, using Daphnia magna as a test organism. Toxicity identification evaluation (TIE) procedures were used to identify the toxicants in textile dyeing effluent, and Jar testing to simulate the Fenton process was conducted to identify the source of toxicants. Textile dyeing effluent was acutely toxic to D. magna [from 1.5 to 9.7 toxic units (TU)] during the study period. TIE results showed that Zn derived from the Fenton process was a key toxicant in textile dyeing effluent. Additionally, Jar testing revealed that low-purity Fenton reagents (FeCl 2 and FeSO 4 ), which contained large amounts of Zn (89 838 and 610 mg L -1 , respectively), were the source of toxicity. Although we were unable to conclusively identify the residual toxicity (approx. 1.4 TU of 9.71 TU) attributable to unknown toxicants in textile dyeing effluent, the findings of this study suggest that careful operation of the Fenton treatment process could contribute to eliminating its unintended toxic effects on aquatic organisms.

Photo degradation of methyl orange an azo dye by advanced Fenton process using zero valent metallic iron: influence of various reaction parameters and its degradation mechanism.

PubMed

Gomathi Devi, L; Girish Kumar, S; Mohan Reddy, K; Munikrishnappa, C

2009-05-30

Advanced Fenton process (AFP) using zero valent metallic iron (ZVMI) is studied as a potential technique to degrade the azo dye in the aqueous medium. The influence of various reaction parameters like effect of iron dosage, concentration of H(2)O(2)/ammonium per sulfate (APS), initial dye concentration, effect of pH and the influence of radical scavenger are studied and optimum conditions are reported. The degradation rate decreased at higher iron dosages and also at higher oxidant concentrations due to the surface precipitation which deactivates the iron surface. The rate constant for the processes Fe(0)/UV and Fe(0)/APS/UV is twice compared to their respective Fe(0)/dark and Fe(0)/APS/dark processes. The rate constant for Fe(0)/H(2)O(2)/UV process is four times higher than Fe(0)/H(2)O(2)/dark process. The increase in the efficiency of Fe(0)/UV process is attributed to the cleavage of stable iron complexes which produces Fe(2+) ions that participates in cyclic Fenton mechanism for the generation of hydroxyl radicals. The increase in the efficiency of Fe(0)/APS/UV or H(2)O(2) compared to dark process is due to continuous generation of hydroxyl radicals and also due to the frequent photo reduction of Fe(3+) ions to Fe(2+) ions. Though H(2)O(2) is a better oxidant than APS in all respects, but it is more susceptible to deactivation by hydroxyl radical scavengers. The decrease in the rate constant in the presence of hydroxyl radical scavenger is more for H(2)O(2) than APS. Iron powder retains its recycling efficiency better in the presence of H(2)O(2) than APS. The decrease in the degradation rate in the presence of APS as an oxidant is due to the fact that generation of free radicals on iron surface is slower compared to H(2)O(2). Also, the excess acidity provided by APS retards the degradation rate as excess H(+) ions acts as hydroxyl radical scavenger. The degradation of Methyl Orange (MO) using Fe(0) is an acid driven process shows higher efficiency at pH 3. The efficiency of various processes for the de colorization of MO dye is of the following order: Fe(0)/H(2)O(2)/UV>Fe(0)/H(2)O(2)/dark>Fe(0)/APS/UV>Fe(0)/UV>Fe(0)/APS/dark>H(2)O(2)/UV approximately Fe(0)/dark>APS/UV. Dye resisted to degradation in the presence of oxidizing agent in dark. The degradation process was followed by UV-vis and GC-MS spectroscopic techniques. Based on the intermediates obtained probable degradation mechanism has been proposed. The result suggests that complete degradation of the dye was achieved in the presence of oxidizing agent when the system was amended with iron powder under UV light illumination. The concentration of Fe(2+) ions leached at the end of the optimized degradation experiment is found to be 2.78 x 10(-3)M. With optimization, the degradation using Fe(0) can be effective way to treat azo dyes in aqueous solution.

Self-Assembled Nano-FeO(OH)/Reduced Graphene Oxide Aerogel as a Reusable Catalyst for Photo-Fenton Degradation of Phenolic Organics.

PubMed

Liu, Renlan; Xu, Yiming; Chen, Baoliang

2018-06-19

Fabrication of visible-light-responsive, macroscopic photo-Fenton catalysts is crucial for wastewater treatment. Here, we report a facile fabrication method for nano-FeO(OH)/reduced graphene oxide aerogels (FeO(OH)-rGA) equipped with a stable macrostructure and a high efficiency for catalytic degradation of phenolic organics. The structure of FeO(OH)/rGA was characterized by SEM, TEM, XPS, Raman analysis. The FeO(OH) is the main constituent of ferrihydrite, which dispersed in the graphene aerogel with a particle size of ∼3 nm can efficiently activate H 2 O 2 to generate abundant •OH. The excellent performance of the FeO(OH)/rGO aerogel was specifically exhibited by the outstanding catalyst activity, sustained mineralization and eminent reaction rate for phenolic organics. A synergy effect between FeO(OH) and graphene aerogel was observed, which came from the extensive electron transfer channels and active sites of the 3D graphene aerogel and the visible-light-activated FeO(OH) and H 2 O 2 consistently producing •OH. The FeO(OH)/rGA could be reused for 10 cycles without a reduction in the catalytic activity and had less iron leaching, which guarantees that the active ingredient remains in the gel. Moreover, the FeO(OH)/rGA induced photo-Fenton degradation of 4-chlorophenol under near neutral pH conditions because the tight connection of FeO(OH) with the rGO aerogel results in less iron leaching and prevents the generation of Fe(OH) 3 . The 4-chlorophenol was completely removed in 80 min with a 0.074 min -1 rate constant in the FeO(OH)-rGA/H 2 O 2 photo-Fenton system under visible-light irradiation, and mineralization rate was up to 80% after 6 h. Oxidative •OH can continuously attack 4-chlorophenol, 2,4,6-trichlorophenol and bisphenol A without selectivity. These results lay a foundation for highly effective and durable photo-Fenton degradation of phenolic organics at near neutral pH and sufficient activation of H 2 O 2 for future applications.

Heterogeneous photo-Fenton processes using graphite carbon coating hollow CuFe2O4 spheres for the degradation of methylene blue

NASA Astrophysics Data System (ADS)

Guo, Xiaojun; Wang, Kebai; Li, Dai; Qin, Jiabin

2017-10-01

The novel graphite carbon coating hollow CuFe2O4 spheres were fabricated through solvothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectra, etc. The catalytic performance of the graphite carbon coating hollow CuFe2O4 spheres was evaluated in photo-Fenton-like degradation of methylene blue (MB) using H2O2 as a green oxidant under light irradiation (λ > 400 nm). The results demonstrated that the hollow CuFe2O4 spheres with graphite carbon coating exhibited superior catalytic activity. In the preparation process of catalyst, the addition of glucose was very important to its catalytic performance. Photoresponse analysis of the typical samples proved that CuFe2O4@graphite carbon core-shell hollow spheres possessed excellent photocurrent response and lower electrochemical impedance. In addition, a possible mechanism for photocatalytic degradation of MB had been presumed. Moreover, after five regeneration cycles, the graphite carbon coating hollow CuFe2O4 spheres still exhibited better properties.

Oxidative damage in DNA bases revealed by UV resonant Raman spectroscopy.

PubMed

D'Amico, Francesco; Cammisuli, Francesca; Addobbati, Riccardo; Rizzardi, Clara; Gessini, Alessandro; Masciovecchio, Claudio; Rossi, Barbara; Pascolo, Lorella

2015-03-07

We report on the use of the UV Raman technique to monitor the oxidative damage of deoxynucleotide triphosphates (dATP, dGTP, dCTP and dTTP) and DNA (plasmid vector) solutions. Nucleotide and DNA aqueous solutions were exposed to hydrogen peroxide (H2O2) and iron containing carbon nanotubes (CNTs) to produce Fenton's reaction and induce oxidative damage. UV Raman spectroscopy is shown to be maximally efficient to reveal changes in the nitrogenous bases during the oxidative mechanisms occurring on these molecules. The analysis of Raman spectra, supported by numerical computations, revealed that the Fenton's reaction causes an oxidation of the nitrogenous bases in dATP, dGTP and dCTP solutions leading to the production of 2-hydroxyadenine, 8-hydroxyguanine and 5-hydroxycytosine. No thymine change was revealed in the dTTP solution under the same conditions. Compared to single nucleotide solutions, plasmid DNA oxidation has resulted in more radical damage that causes the breaking of the adenine and guanine aromatic rings. Our study demonstrates the advantage of using UV Raman spectroscopy for rapidly monitoring the oxidation changes in DNA aqueous solutions that can be assigned to specific nitrogenous bases.

Adsorption of Vanadium (V) from SCR Catalyst Leaching Solution and Application in Methyl Orange.

PubMed

Sha, Xuelong; Ma, Wei; Meng, Fanqing; Wang, Ren; Fuping, Tian; Wei, Linsen

2016-12-01

  In this study, we explored an effective and low-cost catalyst and its adsorption capacity and catalytic capacity for Methyl Orange Fenton oxidation degradation were investigated. The catalyst was directly prepared by reuse of magnetic iron oxide (Fe3O4) after saturated adsorption of vanadium (V) from waste SCR (Selective Catalytic Reduction) catalyst. The obtained catalyst was characterized by FTIR, XPS and the results showed that vanadium (V) adsorption process of Fe3O4 nanoparticles was non-redox reaction. The effects of pH, adsorption kinetics and equilibrium isotherms of adsorption were assessed. Adsorption of vanadium (V) ions by Fe3O4 nanoparticles could be well described by the Sips isotherm model which controlled by the mixed surface reaction and diffusion (MSRDC) adsorption kinetic model. The results show that vanadium (V) was mainly adsorbed on external surface of the Fe3O4 nanoparticles. The separation-recovering tungsten (VI) and vanadium (V) from waste SCR catalyst alkaline solution through pH adjustment was also investigated in this study. The results obtained from the experiments indicated that tungsten (VI) was selectively adsorbed from vanadium (V)/tungsten (VI) mixed solution in certain acidic condition by Fe3O4 nanoparticle to realize their recovery. Tungsten (V) with some impurity can be obtained by releasing from adsorbent, which can be confirmed by ICP-AES. The Methyl Orange degradation catalytic performance illustrated that the catalyst could improve Fenton reaction effectively at pH = 3.0 compare to Fe3O4 nanoparticles alone. Therefore, Fe3O4 nanoparticle adsorbed vanadium (V) has a potential to be employed as a heterogeneous Fenton-like catalyst in the present contribution, and its catalytic activity was mainly evaluated in terms of the decoloration efficiency of Methyl Orange.

In-Situ Regeneration of Saturated Granular Activated Carbon by an Iron Oxide Nanocatalyst

EPA Science Inventory

Granular activated carbon (GAC) can remove trace organic pollutants and natural organic matter (NOM) from industrial and municipal waters. This paper evaluates an iron nanocatalyst approach, based on Fenton-like oxidation reactions, to regenerate spent GAC within a packed bed con...

Mn(2+)-mediated homogeneous Fenton-like reaction of Fe(III)-NTA complex for efficient degradation of organic contaminants under neutral conditions.

PubMed

Li, Yifan; Sun, Jianhui; Sun, Sheng-Peng

2016-08-05

In this work, we report a novel Mn(2+)-mediated Fenton-like process based on Fe(III)-NTA complex that is super-efficient at circumneutral pH range. Kinetics experiments showed that the presence of Mn(2+) significantly enhanced the effectiveness of Fe(III)-NTA complex catalyzed Fenton-like reaction. The degradation rate constant of crotamiton (CRMT), a model compound, by the Fe(III)- NTA_Mn(2+) Fenton-like process was at least 1.6 orders of magnitude larger than that in the absence of Mn(2+). Other metal ions such as Ca(2+), Mg(2+), Co(2+) and Cu(2+) had no impacts or little inhibitory effect on the Fe(III)-NTA complex catalyzed Fenton-like reaction. The generation of hydroxyl radical (HO) and superoxide radical anion (O2(-)) in the Fe(III)-NTA_Mn(2+) Fenton-like process were suggested by radicals scavenging experiments. The degradation efficiency of CRMT was inhibited significantly (approximately 92%) by the addition of HO scavenger 2-propanol, while the addition of O2(-) scavenger chloroform resulted in 68% inhibition. Moreover, the results showed that other chelating agents such as EDTA- and s,s-EDDS-Fe(III) catalyzed Fenton-like reactions were also enhanced significantly by the presence of Mn(2+). The mechanism involves an enhanced generation of O2(-) from the reactions of Mn(2+)-chelates with H2O2, indirectly promoting the generation of HO by accelerating the reduction rate of Fe(III)-chelates to Fe(II)- chelates. Copyright © 2016 Elsevier B.V. All rights reserved.

Photo-fenton degradation of diclofenac: identification of main intermediates and degradation pathway.

PubMed

Pérez-Estrada, Leónidas A; Malato, Sixto; Gernjak, Wolfgang; Agüera, Ana; Thurman, E Michael; Ferrer, Imma; Fernández-Alba, Amadeo R

2005-11-01

In recent years, the presence of pharmaceuticals in the aquatic environment has been of growing interest. These new contaminants are important because many of them are not degraded under the typical biological treatments applied in the wastewater treatment plants and represent a continuous input into the environment. Thus, compounds such as diclofenac are present in surface waters in all Europe and a crucial need for more enhanced technologies that can reduce its presence in the environment has become evident. In this sense, advanced oxidation processes (AOPs) represent a good choice for the treatment of hazardous nonbiodegradable pollutants. This work deals with the solar photodegradation of diclofenac, an antiinflammatory drug, in aqueous solutions by photo-Fenton reaction. A pilot-scale facility using a compound parabolic collector (CPC) reactor was used for this study. Results obtained show rapid and complete oxidation of diclofenac after 60 min, and total mineralization (disappearance of dissolved organic carbon, DOC) after 100 min of exposure to sunlight. Although diclofenac precipitates during the process at low pH, its degradation takes place in the homogeneous phase governed by a precipitation-redissolution-degradation process. Establishment of the reaction pathway was made possible by a thorough analysis of the reaction mixture identifying the main intermediate products generated. Gas chromatography-mass spectrometry (GC/ MS) and liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOF-MS) were used to identify 18 intermediates, in two tentative degradation routes. The main one was based on the initial hydroxylation of the phenylacetic acid moiety in the C-4 position and subsequent formation of a quinone imine derivative that was the starting point for further multistep degradation involving hydroxylation, decarboxylation, and oxidation reactions. An alternative route was based on the transient preservation of the biphenyl amino moiety that underwent a similar oxidative process of C-N bond cleavage. The proposed degradation route differs from those previously reported involving alternative degradation processes (ozonization, UV/H2O2, or photolysis), indicating that diclofenac degradation follows different pathways, depending on the treatment applied.

Coagulation-Fenton coupled treatment for ecotoxicity reduction in highly polluted industrial wastewater.

PubMed

Perdigón-Melón, J A; Carbajo, J B; Petre, A L; Rosal, R; García-Calvo, E

2010-09-15

A coupled coagulation-Fenton process was applied for the treatment of cosmetic industry effluents. In a first step, FeSO(4) was used as coagulant and the non-precipitated Fe(2+) remaining in dissolution was used as catalyst in the further Fenton process. In the coagulation process a huge decrease in total organic carbon (TOC) was achieved, but the high concentration of phenol derivatives was not diminished. The decrease in TOC in the coagulation step significantly reduces the amount of H(2)O(2) required in the Fenton process for phenol depletion. The coupled process, using a H(2)O(2) dose of only 2 g l(-1), reduced TOC and total phenol to values lower than 40 and 0.10 mg l(-1), respectively. The short reaction period (less than 15 min) in TOC and phenol degradation bodes well for improving treatment in a continuous regime. The combination of both processes significantly reduced the ecotoxicity of raw effluent and markedly increased its biodegradability, thus allowing easier treatment by the conventional biological units in conventional sewage treatment plants (STPs). Copyright 2010 Elsevier B.V. All rights reserved.

Notable light-free catalytic activity for pollutant destruction over flower-like BiOI microspheres by a dual-reaction-center Fenton-like process.

PubMed

Wang, Liang; Yan, Dengbiao; Lyu, Lai; Hu, Chun; Jiang, Ning; Zhang, Lili

2018-10-01

BiOI is widely used as photocatalysts for pollutant removal, water splitting, CO 2 reduction and organic transformation due to its excellent photoelectric properties. Here, we report for the first time that a light-free catalyst consisting of the flower-like BiOI microspheres (f-BiOI MSs) exposing (1 0 1) and (1 1 0) crystal planes prepared by a hydrothermal method in ethylene glycol environment can rapidly eliminate the refractory BPA within only ∼3 min through a Fenton-like process. The reaction activity is ∼190 times higher than that of the conventional Fenton catalyst Fe 2 O 3 . A series of characterizations and experiments reveal the formation of the dual reaction centers on f-BiOI MSs. The electron-rich O centers efficiently reduce H 2 O 2 to OH, while the electron-poor oxygen vacancies capture electrons from the adsorbed pollutants and divert them to the electron-rich area during the Fenton-like reactions. By these processes, pollutants are degraded and mineralized quickly in a wide pH range. Our findings address the problems of the classical Fenton reaction and are useful for the development of efficient Fenton-like catalysts through constructing dual reaction centers. Copyright © 2018 Elsevier Inc. All rights reserved.

Photo-Fenton and modified photo-Fenton at neutral pH for the treatment of emerging contaminants in wastewater treatment plant effluents: a comparison.

PubMed

Klamerth, N; Malato, S; Agüera, A; Fernández-Alba, A

2013-02-01

This study compares two different solar photo-Fenton processes, conventional photo-Fenton at pH3 and modified photo-Fenton at neutral pH with minimal Fe (5 mg L⁻¹) and minimal initial H₂O₂ (50 mg L⁻¹) concentrations for the degradation of emerging contaminants in Municipal Wastewater Treatment Plants effluents in solar pilot plant. As Fe precipitates at neutral pH, complexing agents which are able to form photoactive species, do not pollute the environment or increase toxicity have to be used to keep the iron in solution. This study was done using real effluents containing over 60 different contaminants, which were monitored during treatment by liquid chromatography coupled to a hybrid quadrupole/linear ion trap mass analyzer (LC-QTRAP-MS/MS) operating in selected reaction monitoring (SRM) mode. Concentrations of the selected contaminants ranged from a few ng L⁻¹ to tens of μg L⁻¹. It was demonstrated in all cases the removal of over 95% of the contaminants. Photo-Fenton at pH3 provided the best treatment time, but has the disadvantage that the water must be previously acidified. The most promising process was photo-Fenton modified with Ethylenediamine-N,N'-disuccinic acid (EDDS), as the pH remained in the neutral range. Copyright © 2012 Elsevier Ltd. All rights reserved.

What makes a natural clay antibacterial?

USGS Publications Warehouse

Williams, Lynda B.; Metge, David W.; Eberl, Dennis D.; Harvey, Ronald W.; Turner, Amanda G.; Prapaipong, Panjai; Port-Peterson, Amisha T.

2011-01-01

Chemical analyses of E. coli killed by aqueous leachates of an antibacterial clay show that intracellular concentrations of Fe and P are elevated relative to controls. Phosphorus uptake by the cells supports a regulatory role of polyphosphate or phospholipids in controlling Fe2+. Fenton reaction products can degrade critical cell components, but we deduce that extracellular processes do not cause cell death. Rather, Fe2+ overwhelms outer membrane regulatory proteins and is oxidized when it enters the cell, precipitating Fe3+ and producing lethal hydroxyl radicals.

Influence of operational parameters on electro-Fenton degradation of organic pollutants from soil.

PubMed

Rosales, E; Pazos, M; Longo, M A; Sanroman, M A

2009-09-01

The combination of the Fenton's reagent with electrochemistry (the electro-Fenton process) represents an efficient method for wastewater treatment. This study describes the use of this process to clean soil or clay contaminated by organic compounds. Model soil of kaolinite clay polluted with the dye Lissamine Green B (LGB) was used to evaluate the capability of the electro-Fenton process. The effects of operating parameters such as electrode material and dye concentration were investigated. Operating in an electrochemical cell under optimized conditions while using electrodes of graphite, a constant potential difference of 5 V, pH 3, 0.2 mM FeSO(4). 7H(2)O, and electrolyte 0.1 M Na(2)SO(4), around 80% of the LGB dye on kaolinite clay was decolorized after 3 hours with an electric power consumption around 0.15 W h g(-1). Furthermore, the efficiency of this process for the remediation of a real soil polluted with phenanthrene, a typical polycyclic aromatic hydrocarbon, has been demonstrated.

Incorporating biodegradation and advanced oxidation processes in the treatment of spent metalworking fluids.

PubMed

MacAdam, Jitka; Ozgencil, Haci; Autin, Olivier; Pidou, Marc; Temple, Clive; Parsons, Simon; Jefferson, Bruce

2012-12-01

The treatment of spent metalworking fluids (MWFs) is difficult due to their complex and variable composition. Small businesses often struggle to meet increasingly stringent legislation and rising costs as they need to treat this wastewater on site annually over a short period. Larger businesses that treat their wastewater continuously can benefit from the use of biological processes, although new MWFs designed to resist biological activity represent a challenge. A three-stage treatment is generally applied, with the oil phase being removed first, followed by a reduction in COD loading and then polishing of the effluent's quality in the final stage. The performance of advanced oxidation processes (AOPs), which could be of benefit to both types of businesses was studied. After assessing the biodegradability of spent MFW, different AOPs were used (UV/H2O2, photo-Fenton and UV/TiO2) to establish the treatability of this wastewater by hydroxyl radicals (*OH). The interactions of both the chemical and biological treatments were also investigated. The wastewater was found to be readily biodegradable in the Zahn-Wellens test with 69% COD and 74% DOC removal. The UV/TiO2 reactor was found to be the cheapest option achieving a very good COD removal (82% at 20 min retention time and 10 L min(-1) aeration rate). The photo-Fenton process was found to be efficient in terms of degradation rate, achieving 84% COD removal (1 M Fe2+, 40 M H2O2, 20.7 J cm(-2), pH 3) and also improving the wastewater's biodegradability. The UV/H202 process was the most effective in removing recalcitrant COD in the post-biological treatment stage.

Confirming Pseudomonas putida as a reliable bioassay for demonstrating biocompatibility enhancement by solar photo-oxidative processes of a biorecalcitrant effluent.

PubMed

García-Ripoll, A; Amat, A M; Arques, A; Vicente, R; Ballesteros Martín, M M; Pérez, J A Sánchez; Oller, I; Malato, S

2009-03-15

Experiments based on Vibrio fischeri, activated sludge and Pseudomonas putida have been employed to check variation in the biocompatibility of an aqueous solution of a commercial pesticide, along solar photo-oxidative process (TiO(2) and Fenton reagent). Activated sludge-based experiments have demonstrated a complete detoxification of the solution, although important toxicity is still detected according to the more sensitive V. fischeri assays. In parallel, the biodegradability of organic matter is strongly enhanced, with BOD(5)/COD ratio above 0.8. Bioassays run with P. putida have given similar trends, remarking the convenience of using P. putida culture as a reliable and reproducible method for assessing both toxicity and biodegradability, as a substitute to other more time consuming methods.

Impact of the Fenton-like treatment on the microbial community of a diesel-contaminated soil.

PubMed

Polli, Flavia; Zingaretti, Daniela; Crognale, Silvia; Pesciaroli, Lorena; D'Annibale, Alessandro; Petruccioli, Maurizio; Baciocchi, Renato

2018-01-01

Fenton-like treatment (FLT) is an ISCO technique relying on the iron-induced H 2 O 2 activation in the presence of additives aimed at increasing the oxidant lifetime and maximizing iron solubility under natural soil pH conditions. The efficacy of FLT in the clean-up of hydrocarbon-contaminated soils is well established at the field-scale. However, a better assessment of the impact of the FLT on density, diversity and activity of the indigenous soil microbiota, might provide further insights into an optimal combination between FLT and in-situ bioremediation (ISB). The aim of this work was to assess the impacts of FLT on the microbial community of a diesel-contaminated soil collected nearby a gasoline station. Different FLT conditions were tested by varying either the H 2 O 2 concentrations (2 and 6%) or the oxidant application mode (single or double dosage). The impact of these treatments on the indigenous microbial community was assessed immediately after the Fenton-like treatment and after 30, 60 and 90 d and compared with enhanced natural attenuation (ENA). After FLT, a dramatic decrease in bacterial density, diversity and functionality was evident. Although in microcosms with double dosing at 2% H 2 O 2 a delayed recovery of the indigenous microbiota was observed as compared to those subjected to single oxidant dose, after 60 d incubation the respiration rate increased from 0.036 to 0.256 μg CCO 2 g -1 soil h -1 . Irrespective of the oxidant dose, best degradation results after 90 d incubation (around 80%) were observed with combined FLT, relying on double oxidant addition, and bioremediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Treatment of Actual Chemical Wastewater by a Heterogeneous Fenton Process Using Natural Pyrite

PubMed Central

Sun, Liang; Li, Yan; Li, Aimin

2015-01-01

Wastewater from chemical plants has remarkable antibiotic effects on the microorganisms in traditional biological treatment processes. An enhanced Fenton system catalyzed by natural pyrite was developed to degrade this kind of wastewater. Approximately 30% chemical oxygen demand (COD) was removed within 120 min when 50 mmol/L H2O2 and 10 g/L natural pyrite were used at initial pH from 1.8 to 7. A BOD5/COD enhancement efficiency of 210% and an acute biotoxicity removal efficiency of 84% were achieved. The COD removal efficiency was less sensitive to initial pH than was the classic Fenton process. Excessive amounts of pyrite and H2O2 did not negatively affect the pyrite Fenton system. The amount of aniline generated indicated that nitrobenzene reduction by pyrite was promoted using a low initial concentration of H2O2 (<5 mmol/L). Fluorescence excitation emission matrix analyses illustrated that H2O2 facilitated the reduction by natural pyrite of organic molecules containing an electron-withdrawing group to electron-donating group. Thus, the Fenton-like process catalyzed by pyrite can remediate wastewater containing organic pollutants under mild reaction conditions and provide an alternative environmentally friendly method by which to reuse natural pyrite. PMID:26516893

Insights into the Role of Humic Acid on Pd-catalytic Electro-Fenton Transformation of Toluene in Groundwater

PubMed Central

Liao, Peng; Al-Ani, Yasir; Malik Ismael, Zainab; Wu, Xiaohui

2015-01-01

A recently developed Pd-based electro-Fenton (E-Fenton) process enables efficient in situ remediation of organic contaminants in groundwater. In the process, H2O2, Fe(II), and acidic conditions (~pH 3) are produced in situ to facilitate the decontamination, but the role of ubiquitous natural organic matters (NOM) remain unclear. This study investigated the effect of Aldrich humic acid (HA) on the transformation of toluene by the Pd-based E-Fenton process. At pH 3 with 50 mA current, the presence of HA promoted the efficiency of toluene transformation, with pseudo-first-order rate constants increase from 0.01 to 0.016 as the HA concentration increases from 0 to 20 mg/L. The HA-enhanced toluene transformation was attributed to the accelerated thermal reduction of Fe(III) to Fe(II), which led to production of more hydroxyl radicals. The correlation of the rate constants of toluene transformation and HA decomposition validated hydroxyl radical (·OH) as the predominant reactive species for HA decomposition. The finding of this study highlighted that application of the novel Pd-based E-Fenton process in groundwater remediation may not be concerned by the fouling from humic substances. PMID:25783864

Insights into the role of humic acid on Pd-catalytic electro-Fenton transformation of toluene in groundwater.

PubMed

Liao, Peng; Al-Ani, Yasir; Malik Ismael, Zainab; Wu, Xiaohui

2015-03-18

A recently developed Pd-based electro-Fenton (E-Fenton) process enables efficient in situ remediation of organic contaminants in groundwater. In the process, H₂O₂, Fe(II), and acidic conditions (~pH 3) are produced in situ to facilitate the decontamination, but the role of ubiquitous natural organic matters (NOM) remain unclear. This study investigated the effect of Aldrich humic acid (HA) on the transformation of toluene by the Pd-based E-Fenton process. At pH 3 with 50 mA current, the presence of HA promoted the efficiency of toluene transformation, with pseudo-first-order rate constants increase from 0.01 to 0.016 as the HA concentration increases from 0 to 20 mg/L. The HA-enhanced toluene transformation was attributed to the accelerated thermal reduction of Fe(III) to Fe(II), which led to production of more hydroxyl radicals. The correlation of the rate constants of toluene transformation and HA decomposition validated hydroxyl radical (·OH) as the predominant reactive species for HA decomposition. The finding of this study highlighted that application of the novel Pd-based E-Fenton process in groundwater remediation may not be concerned by the fouling from humic substances.

Integrating the Fenton's Process with Biofiltration by to Reduce Chemical Oxygen Demand of Winery Effluents.

PubMed

Pipolo, Marco; Martins, Rui C; Quinta-Ferreira, Rosa M; Costa, Raquel

2017-03-01

The discharge of poorly decontaminated winery wastewater remains a serious environmental problem in many regions, and the industry is welcoming improved treatment methods. Here, an innovative decontamination approach integrating Fenton's process with biofiltration by Asian clams is proposed. The potential of this approach was assessed at the pilot scale using real effluent and by taking an actual industrial treatment system as a benchmark. Fenton peroxidation was observed to remove 84% of the effluent's chemical oxygen demand (COD), reducing it to 205 mg L. Subsequent biofiltration decreased the effluent's COD to approximately zero, well below the legal discharge limit of 150 mg L, in just 3 d. The reduction of the effluent's organic load through Fenton's process did not decrease its toxicity toward , but the effluent was much less harmful after biofiltration. The performance of the treatment proposed exceeded that of the integrated Fenton's process-sequencing batch reactor design implemented in the winery practice, where a residence time of around 10 d in the biological step typically results in 80 to 90% of COD removal. The method proposed is effective and compatible with typical winery budgets and potentially contributes to the management of a nuisance species. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

2,4-D abatement from groundwater samples by photo-Fenton processes at circumneutral pH using naturally iron present. Effect of inorganic ions.

PubMed

Gutiérrez-Zapata, Héctor M; Rojas, Karen L; Sanabria, Janeth; Rengifo-Herrera, Julián Andrés

2017-03-01

This study evaluated, at laboratory scale, if the using iron naturally present (0.3 mg L -1 ) and adding 10 mg L -1 of hydrogen peroxide was effective to remove 24.3 mgL -1 of 2,4-dichlorophenoxyacetic acid (2,4-D) from groundwater samples by simulated solar irradiation (global intensity = 300 W m -2 ). Under these conditions, the degradation of 2,4-D reached 75.2 % and the apparition of its main oxidation byproduct 2,4-dichlorophenol (DCP) was observed. On the other hand, pH exhibited an increasing from 7.0 to 8.3 during the experiment. Experiments using Milli-Q water at pH 7.0, iron, and H 2 O 2 concentrations of 0.3 and 10 mg L -1 , respectively, were carried out in order to study the effect of ions such as carbonate species, phosphate, and fluoride in typical concentrations often found in groundwater. Ion concentrations were combined by using a factorial experimental design 2 3 . Results showed that carbonates and fluoride did not produce a detrimental effect on the 2,4-D degradation, while phosphate inhibited the process. In this case, the pH increased also from 7.0 to 7.95 and 8.99. Effect of parameters such as pH, iron concentration, and hydrogen peroxide concentration on the 2,4-D degradation by the photo-Fenton process in groundwater was evaluated by using a factorial experimental design 2 3 . Results showed that the pH was the main parameter affecting the process. This study shows for the first time that using the photo-Fenton process at circumneutral pH and iron naturally present seems to be a promising process to remove pesticides from groundwater.

Coupling of acrylic dyeing wastewater treatment by heterogeneous Fenton oxidation in a continuous stirred tank reactor with biological degradation in a sequential batch reactor.

PubMed

Esteves, Bruno M; Rodrigues, Carmen S D; Boaventura, Rui A R; Maldonado-Hódar, F J; Madeira, Luís M

2016-01-15

This work deals with the treatment of a recalcitrant effluent, from the dyeing stage of acrylic fibres, by combination of the heterogeneous Fenton's process in a continuous stirred tank reactor (CSTR) with biological degradation in a sequential batch reactor (SBR). Three different catalysts (a commercial Fe/ZSM-5 zeolite and two distinct Fe-containing activated carbons - ACs - prepared by wet impregnation of iron acetate and iron nitrate) were employed on the Fenton's process, and afterwards a parametric study was carried out to determine the effect of the main operating conditions, namely the hydrogen peroxide feed concentration, temperature and contact time. Under the best operating conditions found, using the activated carbon impregnated with iron nitrate, 62.7% of discolouration and 39.9% of total organic carbon (TOC) reduction were achieved, at steady-state. Furthermore, a considerable increase in the effluent's biodegradability was attained (BOD5:COD ratio increased from <0.001 to 0.27 and SOUR - specific oxygen uptake rate - from <0.2 to 11.1 mg O2/(gVSS·h)), alongside a major decrease in its toxicity (from 92.1 to 94.0% of Vibrio fischeri inhibition down to 6.9-9.9%). This allowed the application of the subsequent biological degradation stage. The combination of the two processes provided a treated effluent that clearly complies with the legislated discharge limits. It was also found that the iron leaching from the three catalysts tested was very small in all runs, a crucial factor for the stability and long-term use of such materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fenton and Fenton-like oxidation of pesticide acetamiprid in water samples: kinetic study of the degradation and optimization using response surface methodology.

PubMed

Mitsika, Elena E; Christophoridis, Christophoros; Fytianos, Konstantinos

2013-11-01

The aims of this study were (a) to evaluate the degradation of acetamiprid with the use of Fenton reaction, (b) to investigate the effect of different concentrations of H2O2 and Fe(2+), initial pH and various iron salts, on the degradation of acetamiprid and (c) to apply response surface methodology for the evaluation of degradation kinetics. The kinetic study revealed a two-stage process, described by pseudo- first and second order kinetics. Different H2O2:Fe(2+) molar ratios were examined for their effect on acetamiprid degradation kinetics. The ratio of 3 mg L(-1) Fe(2+): 40 mg L(-1) H2O2 was found to completely remove acetamiprid at less than 10 min. Degradation rate was faster at lower pH, with the optimal value at pH 2.9, while Mohr salt appeared to degrade acetamiprid faster. A central composite design was selected in order to observe the effects of Fe(2+) and H2O2 initial concentration on acetamiprid degradation kinetics. A quadratic model fitted the experimental data, with satisfactory regression and fit. The most significant effect on the degradation of acetamiprid, was induced by ferrous iron concentration followed by H2O2. Optimization, aiming to minimize the applied ferrous concentration and the process time, proposed a ratio of 7.76 mg L(-1) Fe(II): 19.78 mg L(-1) H2O2. DOC is reduced much more slowly and requires more than 6h of processing for 50% degradation. The use to zero valent iron, demonstrated fast kinetic rates with acetamiprid degradation occurring in 10 min and effective DOC removal. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solar photo-Fenton treatment of carbofuran: analysis of mineralization, toxicity, and organic by-products.

PubMed

Lopez-Alvarez, Blady; Torres-Palma, Ricardo A; Ferraro, Franklin; Peñuela, Gustavo

2012-01-01

The degradation of the pesticide carbofuran (CBF) using solar photo-Fenton treatment, at both the laboratory and the pilot scale, was evaluated. At the laboratory scale, in a suntest reactor, the Fe(2+) concentration and H(2)O(2) concentration were evaluated and optimized using the surface response methodology and the Pareto diagram. Under optimal conditions experiments were performed to evaluate the evolution of the substrate removal, oxidation, subsequent mineralization, toxicity and the formation of chloride ions during the treatment. The analysis and evolution of five CBF by-products as well as several control and reactivity tests at the density functional theory level were used to depict a general scheme of the main degradation pathway of CBF via the photo-Fenton system. Finally, at the pilot scale, a sample of the commercial CBF product Furadan was eliminated after 420 min by the photo-Fenton system using direct sunlight. Under these conditions, after 900 min 89% of toxicity (1/E(50) on Vibrio fischeri bacteria), 97% of chemical oxygen demand, and 90% of dissolved organic carbon were removed.

Selected heavy metals speciation in chemically stabilised sewage sludge

NASA Astrophysics Data System (ADS)

Wiśniowska, Ewa; Włodarczyk-Makuła, Marła

2017-11-01

Selected heavy metals (Pb, Ni, Cd) were analysed in soil, digested sewage sludge as well as in the sludge stabilised with CaO or Fenton's reagent. The dose of Fenton's reagent was as follows: Fe2+ = 1g.L-1, Fe2+/H2O2=1:100; stabilisation lasted for 2 h. Dose of CaO was equal to 1 g CaO.g d.m.-1 Total concentration of all metals in the digested sewage sludge was higher than in the soil. Chemical stabilisation of sludge with Fenton's reagent increased total metal content in the sludge as a result of total solids removal. Opposite effect was stated when the sludge was mixed with CaO. Also chemical fractions of heavy metals were identified (exchangeable, carbonate bound, iron oxides bound, organic and residual). The results indicate that stabilisation of the sludge with Fenton's reagent increased mobility of heavy metals compared to the digested sludge. Amendment of CaO increased percent share of examined metals in residual fraction, thus immobilised them and decreased their bioavailability.

Oxidative degradation of phenols in sono-Fenton-like systems upon high-frequency ultrasound irradiation

NASA Astrophysics Data System (ADS)

Aseev, D. G.; Sizykh, M. R.; Batoeva, A. A.

2017-12-01

The kinetics of oxidative degradation of phenol and chlorophenols upon acoustic cavitation in the megahertz range (1.7 MHz) is studied experimentally in model systems, and the involvement of in situ generated reactive oxygen species (ROSs) is demonstrated. The phenols subjected to high frequency ultrasound (HFUS) are ranked in terms of their rate of conversion: 2,4,6-trichlorophenol > 2,4-dichlorophenol 2-chlorophenol > 4-chlorophenol phenol. Oxidative degradation upon HFUS irradiation is most efficient at low concentrations of pollutants, due to the low steady-state concentrations of the in situ generated ROSs. A dramatic increase is observed in the efficiency of oxidation in several sonochemical oxidative systems (HFUS in combination with other chemical oxidative factors). The system with added Fe2+ (a sono-Fenton system) derives its efficiency from hydrogen peroxide generated in situ as a result of the recombination of OH radicals. The S2O8 2-/Fe2+/HFUS system has a synergetic effect on substrate oxidation that is attributed to a radical chain mechanism. In terms of the oxidation rates, degrees of conversion, and specific energy efficiencies of 4-chlorophenol oxidation based on the amount of oxidized substance per unit of expended energy the considered sonochemical oxidative systems form the series HFUS < S2O8 2-/HFUS < S2O8 2-/Fe2+/HFUS.

Comparative study on the removal of COD from POME by electrocoagulation and electro-Fenton methods: Process optimization

NASA Astrophysics Data System (ADS)

Chairunnisak, A.; Arifin, B.; Sofyan, H.; Lubis, M. R.; Darmadi

2018-03-01

This research focuses on the Chemical Oxygen Demand (COD) treatment in palm oil mill effluent by electrocoagulation and electro-Fenton methods to solve it. Initially, the aqueous solution precipitates in acid condition at pH of about two. This study focuses on the palm oil mill effluent degradation by Fe electrodes in a simple batch reactor. This work is conducted by using different parameters such as voltage, electrolyte concentration of NaCl, volume of H2O2 and operation time. The processing of data resulted is by using response surface method coupled with Box-Behnken design. The electrocoagulation method results in the optimum COD reduction of 94.53% from operating time of 39.28 minutes, 20 volts, and without electrolyte concentration. For electro-Fenton process, experiment points out that voltage 15.78 volts, electrolyte concentration 0.06 M and H2O2 volume 14.79 ml with time 35.92 minutes yield 99.56% degradation. The result concluded that the electro-Fenton process was more effective to degrade COD of the palm-oil-mill effluent compared to electrocoagulation process.

Comparison of photo-Fenton, O3/H2O2/UV and photocatalytic processes for the treatment of gray water.

PubMed

Hassanshahi, Nahid; Karimi-Jashni, Ayoub

2018-06-21

This research was carried out to compare and optimize the gray water treatment performance by the photo-Fenton, photocatalysis and ozone/H 2 O 2 /UV processes. Experimental design and optimization were carried out using Central Composite Design of Response Surface Methodology. The results of experiments showed that the most effective and influencing factors in photo-Fenton process were H 2 O 2 /Fe 2+ ratio, in ozone/H 2 O 2 /UV experiment were O 3 concentration, H 2 O 2 concentration, reaction time and pH and in photocatalytic process were TiO 2 concentration, pH and reaction time. The highest COD removal in photo-Fenton, ozone/H 2 O 2 /UV and photocatalytic process were 90%, 92% and 55%, respectively. The results were analyzed by design expert software and for all three processes second-order models were proposed to simulate the COD removal efficiency. In conclusion the ozone/H 2 O 2 /UV process is recommended for the treatment of gray water, since it was able to remove both COD and turbidity by 92% and 93%, respectively. Copyright © 2018 Elsevier Inc. All rights reserved.

UV-C radiation based methods for aqueous metoprolol elimination.

PubMed

Rivas, F J; Gimeno, O; Borralho, T; Carbajo, M

2010-07-15

The endocrine disruptor metoprolol has been oxidised in aqueous solution by means of the systems UV-C, UV-C/H(2)O(2), UV-C/percarbonate, UV-C/monopersulfate, UV-C/TiO(2), UV-C/H(2)O(2)/TiO(2) and photo-Fenton. From simple photolysis experiments the quantum yield of metoprolol has been calculated (roughly 5x10(-3) mol Einstein(-1) at circumneutral pH). Addition of free radicals promoters significantly enhanced the metoprolol depletion rate. Mineralization degree was negligible when no promoter was added, while low values were achieved in the presence of either inorganic peroxides or titanium dioxide. The combination of radiation, hydrogen peroxide and TiO(2) increased the mineralization level up to values in the proximity of 45-50% under the best conditions investigated. The photo-Fenton process was the best system in terms of total oxidation (mineralization degree 70%) when optimum conditions were applied. 2010 Elsevier B.V. All rights reserved.

Removal of atrazine and its by-products from water using electrochemical advanced oxidation processes.

PubMed

Komtchou, Simon; Dirany, Ahmad; Drogui, Patrick; Robert, Didier; Lafrance, Pierre

2017-11-15

Atrazine (ATZ) is one of the most common pesticides detected in surface water in Quebec (Canada). The present study was mainly focused on the degradation of ATZ and its by-products using electrochemical advanced oxidation processes such as photo-electro-Fenton (PEF), electro-Fenton (EF) and anodic-oxidation with simultaneous H 2 O 2 formation (AO - H 2 O 2 ). The comparison of these processes showed that PEF process was found to be the most effective process in removing ATZ and its by-products from both synthetic solution (ATZ 0  = 100 μg L -1 ) and real agricultural surface water enriched with ATZ (ATZ 0  = 10 μg L -1 ). Different operating parameters, including wavelength of the light, pH, current density and the presence of natural organic matter (humic acids) were investigated for PEF process using boron-doped diamond (BDD) anode and graphite cathode. The current density and the wavelength of the light were the most important parameters in the ATZ degradation efficiency. The best operating conditions were recorded for the synthetic samples at a current density of 18.2 mA cm -2 , a pH of 3.0 and treatment time of 45 min. Results showed that atrazine-desethyl-desisopropyl (DEDIA) was the most important by-product recorded. More than 99% of ATZ oxidation was recorded after 15 min of treatment and all the concentrations of major by-products were less than the limit of detection after 45 min of treatment. The PEF process was also tested for real surface water contaminated by ATZ: i) with and without addition of iron; ii) without pH adjustment (pH ∼ 6.7) and with pH adjustment (pH ∼ 3.1). In spite of the presence of radical scavenger and iron complexation the PEF process was more effective to remove ATZ from real surface water when the pH value was adjusted near to 3.0. The ATZ removal was 96.0% with 0.01 mM of iron (k app  = 0.13 min -1 ) and 100% with 0.1 mM of iron (k app  = 0.17 min -1 ). Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal of organic matter and ammonium from landfill leachate through different scenarios: Operational cost evaluation in a full-scale case study of a Flemish landfill.

PubMed

Oloibiri, Violet; Chys, Michael; De Wandel, Stijn; Demeestere, Kristof; Van Hulle, Stijn W H

2017-12-01

Several scenarios are available to landfilling facilities to effectively treat leachate at the lowest possible cost. In this study, the performance of various leachate treatment sequences to remove COD and nitrogen from a leachate stream and the associated cost are presented. The results show that, to achieve 100% nitrogen removal, autotrophic nitrogen removal (ANR) or a combination of ANR and nitrification - denitrification (N-dN) is more cost effective than using only the N-dN process (0.58 €/m 3 ) without changing the leachate polishing costs associated with granular activated carbon (GAC). Treatment of N-dN effluent by ozonation or coagulation led to the reduction of the COD concentration by 10% and 59% respectively before GAC adsorption. This reduced GAC costs and subsequently reduced the overall treatment costs by 7% (ozonation) and 22% (coagulation). On the contrary, using Fenton oxidation to reduce the COD concentration of N-dN effluent by 63% increased the overall leachate treatment costs by 3%. Leachate treatment sequences employing ANR for nitrogen removal followed by ozonation or Fenton or coagulation for COD removal and final polishing with GAC are on average 33% cheaper than a sequence with N-dN + GAC only. When ANR is the preceding step and GAC the final step, choice of AOP i.e., ozonation or Fenton did not affect the total treatment costs which amounted to 1.43 (ozonation) and 1.42 €/m 3 (Fenton). In all the investigated leachate treatment trains, the sequence with ANR + coagulation + GAC is the most cost effective at 0.94 €/m 3 . Copyright © 2016 Elsevier Ltd. All rights reserved.

A comparative study of the treatment of ethylene plant spent caustic by neutralization and classical and advanced oxidation.

PubMed

Hawari, Alaa; Ramadan, Hasanat; Abu-Reesh, Ibrahim; Ouederni, Mabrouk

2015-03-15

The treatment of spent caustic produced from an ethylene plant was investigated. In the case of neutralization alone it was found that the maximum removal of sulfide was at pH values below 5.5. The higher percentage removal of sulfides (99% at pH = 1.5) was accompanied with the highest COD removal (88%). For classical oxidation using H2O2 the maximum COD removal percentage reached 89% at pH = 2.5 and at a hydrogen peroxide concentration of 19 mM/L. For the advanced oxidation using Fenton's process it was found that the maximum COD removal of 96.5% was achieved at a hydrogen peroxide/ferrous sulfate ratio of (7:1). Copyright © 2014 Elsevier Ltd. All rights reserved.

In situ electrochemical and photo-electrochemical generation of the fenton reagent: a potentially important new water treatment technology.

PubMed

Peralta-Hernández, J M; Meas-Vong, Yunny; Rodríguez, Francisco J; Chapman, Thomas W; Maldonado, Manuel I; Godínez, Luis A

2006-05-01

In this work, the design and construction of an annular tube reactor for the electrochemical and photo-electrochemical in situ generation of H2O2 are described. By cathodic reduction of dissolved oxygen and the coupled oxidation of water at a UV-illuminated nanocrystalline-TiO2 semiconductor anode, it was found that the electrochemically generated H2O2 can be employed to readily oxidize the model compound Direct Yellow-52 in dilute acidic solution at high rates in the presence of small quantities of dissolved iron(II). Although, the model organic compound is chemically stable under UV radiation, its electrochemical oxidation rate increases substantially when the semiconductor anode is illuminated as compared to the same processes carried out in the dark.

Complementary Sample Preparation Strategies for Analysis of Cereal β-Glucan Oxidation Products by UPLC-MS/MS.

PubMed

Boulos, Samy; Nyström, Laura

2017-01-01

The oxidation of cereal (1→3,1→4)-β-D-glucan can influence the health promoting and technological properties of this linear, soluble homopolysaccharide by introduction of new functional groups or chain scission. Apart from deliberate oxidative modifications, oxidation of β-glucan can already occur during processing and storage, which is mediated by hydroxyl radicals (HO • ) formed by the Fenton reaction. We present four complementary sample preparation strategies to investigate oat and barley β-glucan oxidation products by hydrophilic interaction ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), employing selective enzymatic digestion, graphitized carbon solid phase extraction (SPE), and functional group labeling techniques. The combination of these methods allows for detection of both lytic (C1, C3/4, C5) and non-lytic (C2, C4/3, C6) oxidation products resulting from HO • -attack at different glucose-carbons. By treating oxidized β-glucan with lichenase and β-glucosidase, only oxidized parts of the polymer remained in oligomeric form, which could be separated by SPE from the vast majority of non-oxidized glucose units. This allowed for the detection of oligomers with mid-chain glucuronic acids (C6) and carbonyls, as well as carbonyls at the non-reducing end from lytic C3/C4 oxidation. Neutral reducing ends were detected by reductive amination with anthranilic acid/amide as labeled glucose and cross-ring cleaved units (arabinose, erythrose) after enzyme treatment and SPE. New acidic chain termini were observed by carbodiimide-mediated amidation of carboxylic acids as anilides of gluconic, arabinonic, and erythronic acids. Hence, a full characterization of all types of oxidation products was possible by combining complementary sample preparation strategies. Differences in fine structure depending on source (oat vs. barley) translates to the ratio of observed oxidized oligomers, with in-depth analysis corroborating a random HO • -attack on glucose units irrespective of glycosidic linkage and neighborhood. The method was demonstrated to be (1) sufficiently sensitive to allow for the analysis of oxidation products also from a mild ascorbate-driven Fenton reaction, and (2) to be specific for cereal β-glucan even in the presence of other co-oxidized polysaccharides. This opens doors to applications in food processing to assess potential oxidations and provides the detailed structural basis to understand the effect oxidized functional groups have on β-glucan's health promoting and technological properties.

Complementary Sample Preparation Strategies for Analysis of Cereal β-Glucan Oxidation Products by UPLC-MS/MS

PubMed Central

Boulos, Samy; Nyström, Laura

2017-01-01

The oxidation of cereal (1→3,1→4)-β-D-glucan can influence the health promoting and technological properties of this linear, soluble homopolysaccharide by introduction of new functional groups or chain scission. Apart from deliberate oxidative modifications, oxidation of β-glucan can already occur during processing and storage, which is mediated by hydroxyl radicals (HO•) formed by the Fenton reaction. We present four complementary sample preparation strategies to investigate oat and barley β-glucan oxidation products by hydrophilic interaction ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), employing selective enzymatic digestion, graphitized carbon solid phase extraction (SPE), and functional group labeling techniques. The combination of these methods allows for detection of both lytic (C1, C3/4, C5) and non-lytic (C2, C4/3, C6) oxidation products resulting from HO•-attack at different glucose-carbons. By treating oxidized β-glucan with lichenase and β-glucosidase, only oxidized parts of the polymer remained in oligomeric form, which could be separated by SPE from the vast majority of non-oxidized glucose units. This allowed for the detection of oligomers with mid-chain glucuronic acids (C6) and carbonyls, as well as carbonyls at the non-reducing end from lytic C3/C4 oxidation. Neutral reducing ends were detected by reductive amination with anthranilic acid/amide as labeled glucose and cross-ring cleaved units (arabinose, erythrose) after enzyme treatment and SPE. New acidic chain termini were observed by carbodiimide-mediated amidation of carboxylic acids as anilides of gluconic, arabinonic, and erythronic acids. Hence, a full characterization of all types of oxidation products was possible by combining complementary sample preparation strategies. Differences in fine structure depending on source (oat vs. barley) translates to the ratio of observed oxidized oligomers, with in-depth analysis corroborating a random HO•-attack on glucose units irrespective of glycosidic linkage and neighborhood. The method was demonstrated to be (1) sufficiently sensitive to allow for the analysis of oxidation products also from a mild ascorbate-driven Fenton reaction, and (2) to be specific for cereal β-glucan even in the presence of other co-oxidized polysaccharides. This opens doors to applications in food processing to assess potential oxidations and provides the detailed structural basis to understand the effect oxidized functional groups have on β-glucan's health promoting and technological properties. PMID:29164106

Complementary sample preparation strategies for analysis of cereal β-glucan oxidation products by UPLC-MS/MS

NASA Astrophysics Data System (ADS)

Boulos, Samy; Nyström, Laura

2017-11-01

The oxidation of cereal (1→3,1→4)-β-D-glucan can influence the health promoting and technological properties of this linear, soluble homopolysaccharide by introduction of new functional groups or chain scission. Apart from deliberate oxidative modifications, oxidation of β-glucan can already occur during processing and storage, which is mediated by hydroxyl radicals (HO•) formed by the Fenton reaction. We present four complementary sample preparation strategies to investigate oat and barley β-glucan oxidation products by hydrophilic interaction ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), employing selective enzymatic digestion, graphitized carbon solid phase extraction (SPE), and functional group labeling techniques. The combination of these methods allows for detection of both lytic (C1, C3/4, C5) and non-lytic (C2, C4/3, C6) oxidation products resulting from HO•-attack at different glucose-carbons. By treating oxidized β-glucan with lichenase and β-glucosidase, only oxidized parts of the polymer remained in oligomeric form, which could be separated by SPE from the vast majority of non-oxidized glucose units. This allowed for the detection of oligomers with mid-chain glucuronic acids (C6) and carbonyls, as well as carbonyls at the non-reducing end from lytic C3/C4 oxidation. Neutral reducing ends were detected by reductive amination with anthranilic acid/amide as labeled glucose and cross-ring cleaved units (arabinose, erythrose) after enzyme treatment and SPE. New acidic chain termini were observed by carbodiimide-mediated amidation of carboxylic acids as anilides of gluconic, arabinonic, and erythronic acids. Hence, a full characterization of all types of oxidation products was possible by combining complementary sample preparation strategies. Differences in fine structure depending on source (oat vs. barley) translates to the ratio of observed oxidized oligomers, with in-depth analysis corroborating a random HO•-attack on glucose units irrespective of glycosidic linkage and neighborhood. The method was demonstrated to be 1) sufficiently sensitive to allow for the analysis of oxidation products also from a mild ascorbate-driven Fenton reaction, and 2) to be specific for cereal β-glucan even in the presence of other co-oxidized polysaccharides. This opens doors to applications in food processing to assess potential oxidations and provides the detailed structural basis to understand the effect oxidized functional groups have on β-glucan’s health promoting and technological properties.

Applying fenton process in acrylic fiber wastewater treatment and practice teaching

NASA Astrophysics Data System (ADS)

Zhang, Chunhui; Jiang, Shan

2018-02-01

Acrylic fiber manufacturing wastewater, containing a wider range of pollutants, high concentration of refractory organics, poisonous and harmful matters, was significant to treat from the effluents of wastewater treatment plants (WWTPs). In this work, a Fenton reactor was employed for advanced treatment of the WWTP effluents. An orthogonal test and a parametric study were carried out to determine the effect of the main operating conditions and the Fenton process attain excellent performance on the degradation of pollutants under an optimal condition of ferrous dosage was 6.25 mM, hydrogen peroxide was 75 mM and initial pH value was 3.0 in 90 min reaction time. The removal efficiency of COD, TOC, NH4 +-N and TN reached from 45% to 69%. Lastly, as a teaching advice, the Fenton reactor was used in practicing teaching nicely.

Degradation of carbendazim in water via photo-Fenton in Raceway Pond Reactor: assessment of acute toxicity and transformation products.

PubMed

da Costa, Elizângela Pinheiro; Bottrel, Sue Ellen C; Starling, Maria Clara V M; Leão, Mônica M D; Amorim, Camila Costa

2018-05-08

This study aimed at investigating the degradation of fungicide carbendazim (CBZ) via photo-Fenton reactions in artificially and solar irradiated photoreactors at laboratory scale and in a semi-pilot scale Raceway Pond Reactor (RPR), respectively. Acute toxicity was monitored by assessing the sensibility of bioluminescent bacteria (Aliivibrio fischeri) to samples taken during reactions. In addition, by-products formed during solar photo-Fenton were identified by liquid chromatography coupled to mass spectrometry (UFLC-MS). For tests performed in lab-scale, two artificial irradiation sources were compared (UV λ > 254nm and UV-Vis λ > 320nm ). A complete design of experiments was performed in the semi-pilot scale RPR in order to optimize reaction conditions (Fe 2+ and H 2 O 2 concentrations, and water depth). Efficient degradation of carbendazim (> 96%) and toxicity removal were achieved via artificially irradiated photo-Fenton under both irradiation sources. Control experiments (UV photolysis and UV-Vis peroxidation) were also efficient but led to increased acute toxicity. In addition, H 2 O 2 /UV λ > 254nm required longer reaction time (60 minutes) when compared to the photo-Fenton process (less than 1 min). While Fenton's reagent achieved high CBZ and acute toxicity removal, its efficiency demands higher concentration of reagents in comparison to irradiated processes. Solar photo-Fenton removed carbendazim within 15 min of reaction (96%, 0.75 kJ L -1 ), and monocarbomethoxyguanidine, benzimidazole isocyanate, and 2-aminobenzimidazole were identified as transformation products. Results suggest that both solar photo-Fenton and artificially irradiated systems are promising routes for carbendazim degradation.

Performance evaluation of different solar advanced oxidation processes applied to the treatment of a real textile dyeing wastewater.

PubMed

Manenti, Diego R; Soares, Petrick A; Silva, Tânia F C V; Módenes, Aparecido N; Espinoza-Quiñones, Fernando R; Bergamasco, Rosângela; Boaventura, Rui A R; Vilar, Vítor J P

2015-01-01

The performance of different solar-driven advanced oxidation processes (AOPs), such as TiO2/UV, TiO2/H2O2/UV, and Fe(2+)/H2O2/UV-visible in the treatment of a real textile effluent using a pilot plant with compound parabolic collectors (CPCs), was investigated. The influence of the main photo-Fenton reaction variables such as iron concentration (20-100 mg Fe(2+) L(-1)), pH (2.4-4.5), temperature (10-50 °C), and irradiance (22-68 WUV m(-2)) was evaluated in a lab-scale prototype using artificial solar radiation. The real textile wastewater presented a beige color, with a maximum absorbance peak at 641 nm, alkaline pH (8.1), moderate organic content (dissolved organic carbon (DOC) = 129 mg C L(-1) and chemical oxygen demand (COD) = 496 mg O2 L(-1)), and high conductivity mainly associated to the high concentration of chloride (1.1 g Cl(-) L(-1)), sulfate (0.4 g SO 4 (2 -) L(- 1)), and sodium (1.2 g Na(+) L(-1)) ions. Although all the processes tested contributed to complete decolorization and effective mineralization, the most efficient process was the solar photo-Fenton with an optimum catalyst concentration of 60 mg Fe(2+) L(-1), leading to 70 % mineralization (DOCfinal = 41 mg C L(-1); CODfinal < 150 mg O2 L(-1)) at pH 3.6, requiring a UV energy dose of 3.5 kJUV L(-1) (t 30 W = 22.4 min; [Formula: see text]; [Formula: see text]) and consuming 18.5 mM of H2O2.

INVESTIGATION OF THE RADICAL-MEDIATED PRODUCTION OF BENZENE OXIDE PROTEIN ADDUCTS IN VITRO AND IN VIVO

EPA Science Inventory

High background levels of benzene oxide (BO) adducts with hemoglobin and albumin (BO-Hb and BO-Alb) have been measured in unexposed humans and animals. To test the influence of radical-mediated pathways on production of these BO-protein adducts, we employed Fenton chemistry to...

In-Situ Chemical Reduction and Oxidation of VOCs in Groundwater: Groundwater Treatability Studies

NASA Technical Reports Server (NTRS)

Keith, Amy; Glasgow, Jason; McCaleh, Rececca C. (Technical Monitor)

2001-01-01

This paper presents NASA Marshall Space Flight Center's treatability studies for volatile organic compounds in groundwater. In-Situ groundwater treatment technologies include: 1) Chemical Reduction(Ferox); 2) Chemical Oxidation (Fenton Reagents, Permanganate, and Persulfate); and 3) Thermal (Dynamic Underground Stripping, Six-Phase Heating). This paper is presented in viewgraph form.

Antioxidative properties of the essential oil from Pinus mugo.

PubMed

Grassmann, Johanna; Hippeli, Susanne; Vollmann, Renate; Elstner, Erich F

2003-12-17

The essential oil from Pinus mugo (PMEO) was tested on its antioxidative capacity. For this purpose, several biochemical test systems were chosen (e.g., the Fenton System, the xanthine oxidase assay, or the copper-induced oxidation of low-density lipoprotein (LDL)). The results show that there is moderate or weak antioxidative activity when tested in aqueous environments, like in the Fenton system, xanthine oxidase induced superoxide radical formation, or in the HOCl driven fragmentation of 1-aminocyclopropane-1-carboxylic acid (ACC). In contrast, when tested in more lipophilic environments (e.g., the ACC-cleavage by activated neutrophils in whole blood) the PMEO exhibits good antioxidative activity. PMEO does also show good antioxidative capacity in another lipophilic test system (i.e., the copper induced oxidation of LDL). Some components of PMEO (i.e., Delta(3)-carene, camphene, alpha-pinene, (+)-limonene and terpinolene) were also tested. As the PMEO, they showed weak or no antioxidant activity in aqueous environments, but some of them were effective antioxidants regarding ACC-cleavage by activated neutrophils in whole blood or copper-induced LDL-oxidation. Terpinolene, a minor component of PMEO, exhibited remarkable protection against LDL-oxidation.

Enhancing enzymolysis and fermentation efficiency of sugarcane bagasse by synergistic pretreatment of Fenton reaction and sodium hydroxide extraction.

PubMed

Zhang, Teng; Zhu, Ming-Jun

2016-08-01

A study on the synergistic pretreatment of sugarcane bagasse (SCB) using Fenton reaction and NaOH extraction was conducted. The optimized process conditions for Fenton pretreatment were 10% (w/w) of H2O2, 20mM of Fe(2+), pH 2.5, pretreatment time 6h, and pretreatment temperature 55°C. Sequential pretreatments were performed in combination with NaOH extraction (NaOH 1% (w/w), 80°C, 5% of solid loading, 1h). Among all the pretreatments, Fenton pretreatment followed by NaOH extraction had the highest efficiency of 64.7% and 108.3% for enzymolysis and simultaneous saccharification fermentation (SSF) with an ethanol concentration of 17.44g/L. The analyses by the scanning electron microscopy, X-ray diffraction and confocal laser scanning microscopy revealed that Fenton pretreatment disrupts the structure of SCB to facilitate the degradation of lignin by NaOH. The overall data suggest that this combinatorial strategy is a promising process for SCB pretreatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sequential solar photo-fenton-biological system for the treatment of winery wastewaters.

PubMed

Mosteo, R; Sarasa, J; Ormad, Maria P; Ovelleiro, J L

2008-08-27

In this study, winery wastewaters are considered for degradation using heterogeneous photo-Fenton as a preliminary step before biotreatment. The heterogeneous photo-Fenton process assisted by solar light is able to partially degrade the organic matter present in winery wastewaters. When an initial hydrogen peroxide concentration of 0.1 M is used over 24 h of treatment, a degradation yield of organic matter (measured as TOC) of around 50% is reached. The later treatment (activated sludge process) allows the elimination of 90% of the initial TOC present in pretreated winery wastewaters without producing nondesired side-effects, such as the bulking phenomenon, which is usually detected when this treatment is used alone. The final effluent contains a concentration of organic matter (measured as COD) of 128 mg O2/L. The coupled system comprising the heterogeneous photo-Fenton process and biological treatment based on activated sludge in simple stage is a real alternative for the treatment of winery wastewater.

Integrating Fenton's process and ion exchange for olive mill wastewater treatment and iron recovery.

PubMed

Reis, Patrícia M; Martins, Pedro J M; Martins, Rui C; Gando-Ferreira, Licínio M; Quinta-Ferreira, Rosa M

2018-02-01

A novel integrated methodology involving Fenton's process followed by ion exchange (IE) was proposed for the treatment of olive mill wastewater. Fenton's process was optimized and it was able to remove up to 81% of chemical oxygen demand when pH 3.5, reaction time 1 h, [Fe 2+ ] = 50 mg L -1 and [Fe 2+ ]/[H 2 O 2 ] = 0.002 were applied. In spite of the potential of this treatment approach, final iron removal from the liquid typically entails pH increase and iron sludge production. The integration of an IE procedure using Lewatit TP 207 resin was found to be able to overcome this important environmental shortcoming. The resin showed higher affinity toward Fe 3+ than to Fe 2+ . However, the iron removal efficiency of an effluent coming from Fenton's was independent of the type of the initial iron used in the process. The presence of organic matter had no significant effect over the resin iron removal efficiency. Even if some efficiency decrease was observed when a high initial iron load was applied, the adsorbent mass quantity can be easily adapted to reach the desired iron removal. The use of IE is an interesting industrial approach able to surpass Fenton's peroxidation drawback and will surely boost its full-scale application in the treatment of bio-refractory effluents.

On-line separation and characterization of hyaluronan oligosaccharides derived from radical depolymerization

PubMed Central

Zhao, Xue; Yang, Bo; Li, Lingyun; Zhang, Fuming; Linhardt, Robert J.

2013-01-01

Hydroxyl radicals are widely implicated in the oxidation of carbohydrates in biological and industrial processes and are often responsible for their structural modification resulting in functional damage. In this study, the radical depolymerization of the polysaccharide hyaluronan was studied in a reaction with hydroxyl radicals generated by Fenton Chemistry. A simple method for isolation and identification of the resulting non-sulfated oligosaccharide products of oxidative depolymerization was established. Hyaluronan oligosaccharides were analyzed using ion-pairing reversed phase high performance liquid chromotography coupled with tandem electrospray mass spectrometry. The sequence of saturated hyaluronan oligosaccharides having even- and odd-numbers of saccharide units, afforded through oxidative depolymerization, were identified. This study represents a simple, effective ‘fingerprinting’ protocol for detecting the damage done to hyaluronan by oxidative radicals. This study should help reveal the potential biological outcome of reactive-oxygen radical-mediated depolymerization of hyaluronan. PMID:23768593

An innovative ultrasound, Fe(2+) and TiO(2) photoassisted process for bisphenol A mineralization.

PubMed

Torres-Palma, Ricardo A; Nieto, Jessica I; Combet, Evelyne; Pétrier, Christian; Pulgarin, Cesar

2010-04-01

This paper explores the degradation of a model pollutant, bisphenol A, by an advanced oxidation process that combines sonolysis, Fe(2+), and TiO(2) in a photoassisted process. Experiments were done under saturated oxygen conditions. The effect of different Fe(2+) (0.56 and 5.6 mg/L) and TiO(2) (10 and 50 mg/L) concentrations was investigated on both the elimination and mineralization of the pollutant. A pronounced synergistic effect that led to the complete and rapid elimination of dissolved organic carbon (DOC) was observed even at low catalyst loadings. In this system, almost a complete removal of DOC (93%) was observed after 4 h using 10 and 5.6 mg/L of TiO(2) and Fe(2+), respectively, whereas at the same time, only 5, 6, and 22% of DOC was removed by an individual process alone (TiO(2) photocatalysis, ultrasound, and photo-Fenton, respectively). In this system, ultrasound has the principal role of eliminating the initial substrate and providing hydrogen peroxide for the photocatalytic systems, while photo-Fenton and TiO(2) photocatalysis are mainly responsible for the transformation of the intermediates in CO(2) and H(2)O. The role of H(2)O(2) generated from the sonochemical process is also discussed. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Effect of μM Fe addition, mild heat and solar UV on sulfate radical-mediated inactivation of bacteria, viruses, and micropollutant degradation in water.

PubMed

Marjanovic, Miloch; Giannakis, Stefanos; Grandjean, Dominique; de Alencastro, Luiz Felippe; Pulgarin, Cesar

2018-09-01

In this work, solar disinfection (SODIS) was enhanced by moderate addition of Fe and sodium peroxydisulfate (PDS), under solar light. A systematic assessment of the activating factors was performed, firstly isolated, then in pairs and concluded in the combined Fe/heat/solar UV-PDS activation process. Solar light was the most effective (single) activator, and its combination with Fe and heat (double activation) yielded high level of synergies (up to S = 2.13). The triple activation was able to reduce the bacterial load up to 6-log in less than 1 h, similarly to the photo-Fenton process done in comparison (SODIS alone: >5 h). Fe-oxides were suitable activators of PDS under the same conditions while the presence of organic matter enhanced bacterial inactivation by the triple activated PDS process. The degradation of a (selected) mixture of micropollutants (i.e. drugs, pesticides) was also achieved in similar order of magnitude, and faster than the photo-Fenton process. Finally, the removal of a viral pathogen indicator (MS2 bacteriophage) was attained at minute-range residence times. The aforementioned facts indicate the suitability of the mild, combined process, as a potential SODIS enhancement, producing safe drinking water for sunny and especially for developing countries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effective degradation of rhodamine B by electro-Fenton process, using ferromagnetic nanoparticles loaded on modified graphite felt electrode as reusable catalyst: in neutral pH condition and without external aeration.

PubMed

Tian, Jiangnan; Zhao, Jixiang; Olajuyin, Ayobami Matthew; Sharshar, Moustafa Mohamed; Mu, Tingzhen; Yang, Maohua; Xing, Jianmin

2016-08-01

Polytetrafluoroethylene/ferromagnetic nanoparticle/carbon black (PTFE/MNP/CB)-modified graphite felt (GF) was successfully applied as cathode for the mineralization of rhodamine B (RhB) in electro-Fenton (EF) process. The modified cathode showed high decolorization efficiency for RhB solution even in neutral pH condition and without external aeration, achieving nearly complete decolorization and 89.52 % total organic carbon (TOC) removal after 270-min oxidation with the MNP load 1.2 g at 50 A/m(2). Moreover, the operational parameters (current density, MNP load, initial pH, and airflow rate) were optimized. After that, adsorption isotherm was also conducted to compare the absorption quantity of CB and carbon nanotube (CNT). Then, the surface morphologies of MNPs were characterized by transmission electron microscope (TEM), energy-dispersive X-ray detector (EDX), and Fourier transform infrared spectroscopy (FTIR); and the modified cathode was characterized by SEM and contact angle. Finally, the stability and reusability of modified cathode were tested. Result uncovered that the PTFE/MNP/CB-modified cathode has the potential for industrial application and the solution after treatment was easily biodegradable.

Solar photocatalytic treatment of landfill leachate using a solid mineral by-product as a catalyst.

PubMed

Poblete, Rodrigo; Prieto-Rodríguez, Lucia; Oller, Isabel; Maldonado, Manuel I; Malato, Sixto; Otal, Emilia; Vilches, Luis F; Fernández-Pereira, Constantino

2012-08-01

The treatment of municipal solid waste landfill leachate in a pilot plant made up of solar compound parabolic collectors, using a solid industrial titanium by-product (WTiO(2)) containing TiO(2) and Fe(III) as a photocatalyst, was investigated. In the study evidence was found showing that the degradation performed with WTiO(2) was mainly due to the Fe provided by this by-product, instead of TiO(2). However, although TiO(2) had very little effect by itself, a synergistic effect was observed between Fe and TiO(2). The application of WTiO(2), which produced coupled photo-Fenton and heterogeneous catalysis reactions, achieved a surprisingly high depuration level (86% of COD removal), higher than that reached by photo-Fenton using commercial FeSO(4) (43%) in the same conditions. After the oxidation process the biodegradability and toxicity of the landfill leachate were studied. The results showed that the leachate biodegradability was substantially increased, at least in the first stages of the process, and again that WTiO(2) was more efficient than FeSO(4) in terms of increasing biodegradability. Copyright © 2012 Elsevier Ltd. All rights reserved.

Treatment of industrial wastewater effluents using hydrodynamic cavitation and the advanced Fenton process.

PubMed

Chakinala, Anand G; Gogate, Parag R; Burgess, Arthur E; Bremner, David H

2008-01-01

For the first time, hydrodynamic cavitation induced by a liquid whistle reactor (LWR) has been used in conjunction with the advanced Fenton process (AFP) for the treatment of real industrial wastewater. Semi-batch experiments in the LWR were designed to investigate the performance of the process for two different industrial wastewater samples. The effect of various operating parameters such as pressure, H2O2 concentration and the initial concentration of industrial wastewater samples on the extent of mineralization as measured by total organic carbon (TOC) content have been studied with the aim of maximizing the extent of degradation. It has been observed that higher pressures, sequential addition of hydrogen peroxide at higher loadings and lower concentration of the effluent are more favourable for a rapid TOC mineralization. In general, the novel combination of hydrodynamic cavitation with AFP results in about 60-80% removal of TOC under optimized conditions depending on the type of industrial effluent samples. The combination described herein is most useful for treatment of bio-refractory materials where the diminution in toxicity can be achieved up to a certain level and then conventional biological oxidation can be employed for final treatment. The present work is the first to report the use of a hydrodynamic cavitation technique for real industrial wastewater treatment.

Fenton-like reaction: a possible way to efficiently remove illicit drugs and pharmaceuticals from wastewater.

PubMed

Mackuľak, Tomáš; Mosný, Michal; Grabic, Roman; Golovko, Oksana; Koba, Olga; Birošová, Lucia

2015-03-01

We analyzed 13 psychoactive pharmaceuticals, illicit drugs and their metabolites in wastewater treatment plant influent and effluent and the possibility of their degradation by biological and chemical processes. Tramadol (413-853 ng/L) and methamphetamine (460-682 ng/L) were the most concentrated compounds in the wastewater in winter and summer, respectively. A significant decrease in the concentration of tramadol in wastewater was measured during the summer. The lowest efficiency was observed for tramadol, venlafaxine, citalopram and oxazepam (∼ 10%) and the highest efficiency was observed for amphetamine and THC-COOH (∼ 80%). The efficiency of compound degradation via the Fenton reaction, a modified Fenton reaction and different degradation (by algae, wood-rotting fungi and enzymes at influent versus effluent) was determined. The Fenton reaction and its modification were efficient at eliminating these substances in comparison with the tested biological processes. Copyright © 2015 Elsevier B.V. All rights reserved.

Micro–mesoporous iron oxides with record efficiency for the decomposition of hydrogen peroxide: morphology driven catalysis for the degradation of organic contaminants

EPA Science Inventory

A template-free solid-state synthesis of a morphologically controlled and highly organized iron(III)oxide micro–mesoporous Fenton catalyst has been engineered through a simple two-step synthetic procedure. The 3D nanoassembly of hematite nanoparticles (5–7 nm) organized into a ro...

Efficient treatment of aniline containing wastewater in bipolar membrane microbial electrolysis cell-Fenton system.

PubMed

Li, Xiaohu; Jin, Xiangdan; Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

2017-08-01

Aniline-containing wastewater can cause significant environmental problems and threaten the humans's life. However, rapid degradation of aniline with cost-efficient methods remains a challenge. In this work, a novel microbial electrolysis cell with bipolar membrane was integrated with Fenton reaction (MEC-Fenton) for efficient treatment of real wastewater containing a high concentration (4460 ± 52 mg L -1 ) of aniline. In this system, H 2 O 2 was in situ electro-synthesized from O 2 reduction on the graphite cathode and was simultaneously used as source of OH for the oxidation of aniline wastewater under an acidic condition maintained by the bipolar membrane. The aniline was effectively degraded following first-order kinetics at a rate constant of 0.0166 h -1 under an applied voltage of 0.5 V. Meanwhile, a total organic carbon (TOC) removal efficiency of 93.1 ± 1.2% was obtained, revealing efficient mineralization of aniline. The applicability of bipolar membrane MEC-Fenton system was successfully demonstrated with actual aniline wastewater. Moreover, energy balance showed that the system could be a promising technology for removal of biorefractory organic pollutants from wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Degradation of pharmaceutical beta-blockers by electrochemical advanced oxidation processes using a flow plant with a solar compound parabolic collector.

PubMed

Isarain-Chávez, Eloy; Rodríguez, Rosa María; Cabot, Pere Lluís; Centellas, Francesc; Arias, Conchita; Garrido, José Antonio; Brillas, Enric

2011-08-01

The degradation of the beta-blockers atenolol, metoprolol tartrate and propranolol hydrochloride was studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). Solutions of 10 L of 100 mg L⁻¹ of total organic carbon of each drug in 0.1 M Na₂SO₄ with 0.5 mM Fe²⁺ of pH 3.0 were treated in a recirculation flow plant with an electrochemical reactor coupled with a solar compound parabolic collector. Single Pt/carbon felt (CF) and boron-doped diamond (BDD)/air-diffusion electrode (ADE) cells and combined Pt/ADE-Pt/CF and BDD/ADE-Pt/CF cells were used. SPEF treatments were more potent with the latter cell, yielding 95-97% mineralization with 100% of maximum current efficiency and energy consumptions of about 0.250 kWh g TOC⁻¹. However, the Pt/ADE-Pt/CF cell gave much lower energy consumptions of about 0.080 kWh g TOC⁻¹ with slightly lower mineralization of 88-93%, then being more useful for its possible application at industrial level. The EF method led to a poorer mineralization and was more potent using the combined cells by the additional production of hydroxyl radicals (•OH) from Fenton's reaction from the fast Fe²⁺ regeneration at the CF cathode. Organics were also more rapidly destroyed at BDD than at Pt anode. The decay kinetics of beta-blockers always followed a pseudo first-order reaction, although in SPEF, it was accelerated by the additional production of •OH from the action of UV light of solar irradiation. Aromatic intermediates were also destroyed by hydroxyl radicals. Ultimate carboxylic acids like oxalic and oxamic remained in the treated solutions by EF, but their Fe(III) complexes were photolyzed by solar irradiation in SPEF, thus explaining its higher oxidation power. NO₃⁻ was the predominant inorganic ion lost in EF, whereas the SPEF process favored the production of NH₄⁺ ion and volatile N-derivatives. Copyright © 2011 Elsevier Ltd. All rights reserved.

Improving Software Quality and Management Through Use of Service Level Agreements

DTIC Science & Technology

2005-03-01

many who believe that the quality of the development process is the best predictor of software product quality. ( Fenton ) Repeatable software processes...reduced errors per KLOC for small projects ( Fenton ), and the quality management metric (QMM) (Machniak, Osmundson). There are also numerous IEEE 14...attention to cosmetic user interface issues and any problems that may arise with the prototype. (Sawyer) The validation process is also another check

Evaluation of ethyl lactate as solvent in Fenton oxidation for the remediation of total petroleum hydrocarbon (TPH)-contaminated soil.

PubMed

Jalilian Ahmadkalaei, Seyedeh Pegah; Gan, Suyin; Ng, Hoon Kiat; Abdul Talib, Suhaimi

2017-07-01

Due to the health and environmental risks posed by the presence of petroleum-contaminated areas around the world, remediation of petroleum-contaminated soil has drawn much attention from researchers. Combining Fenton reaction with a solvent has been proposed as a novel way to remediate contaminated soils. In this study, a green solvent, ethyl lactate (EL), has been used in conjunction with Fenton's reagents for the remediation of diesel-contaminated soil. The main aim of this research is to determine how the addition of EL affects Fenton reaction for the destruction of total petroleum hydrocarbons (TPHs) within the diesel range. Specifically, the effects of different parameters, including liquid phase volume-to-soil weight (L/S) ratio, hydrogen peroxide (H 2 O 2 ) concentration and EL% on the removal efficiency, have been studied in batch experiments. The results showed that an increase in H 2 O 2 resulted in an increase in removal efficiency of TPH from 68.41% at H 2 O 2  = 0.1 M to 90.21% at H 2 O 2  = 2 M. The lowest L/S, i.e. L/S = 1, had the highest TPH removal efficiency of 85.77%. An increase in EL% up to 10% increased the removal efficiency to 96.74% for TPH, and with further increase in EL%, the removal efficiency of TPH decreased to 89.6%. EL with an optimum value of 10% was found to be best for TPH removal in EL-based Fenton reaction. The power law and pseudo-first order equations fitted well to the experimental kinetic data of Fenton reactions.

Solar photo-Fenton mineralization of antipyrine in aqueous solution.

PubMed

Durán, A; Monteagudo, J M; Sanmartín, I; Carrasco, A

2013-11-30

The mineralization of an aqueous solution of antipyrine (C11H12N2O), an emerging contaminant, using a solar photocatalytic oxidation process assisted with ferrioxalate was evaluated in a compound parabolic collector (CPC) pilot plant. Under the selected operating conditions ([H2O2] = 250 ppm, [Fe] = 14 ppm, pH = 2.7, and [(COOH)2·2H2O] = 80 ppm), 60% of TOC is removed just 5 min after treating an aqueous solution containing 50 ppm of antipyrine. The addition of oxalic acid up to a maximum concentration of 80 ppm significantly increases the mineralization rate during the first 15 min of the reaction. The synergism between the solar and dark H2O2/ferrioxalate process was quantified at 79%, calculated from the pseudo first-order mineralization rate constants. The operational costs due to the consumption of electrical energy, reagents and catalysts were calculated from the optimal conditions and compared with a novel sono-photocatalytic process using artificial UV-light. The results showed that the ferrioxalate-assisted solar photo-Fenton process was economically feasible, being able to achieve up to 60% mineralization with a total cost of 4.5 cent €/g TOC removed (1.1 €/m(3)). Copyright © 2013 Elsevier Ltd. All rights reserved.

Mineralisation of 2,4-dichlorophenoxyacetic acid by acoustic or hydrodynamic cavitation in conjunction with the advanced Fenton process.

PubMed

Bremner, David H; Carlo, Stefano Di; Chakinala, Anand G; Cravotto, Giancarlo

2008-04-01

The mineralisation of 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence of zero-valent iron and hydrogen peroxide (the advanced Fenton process--AFP) whilst being subjected to acoustic or hydrodynamic cavitation is reported. If the reaction is merely stirred then there is 57% removal of TOC whilst on irradiation the figure is 64% although the latter reaction is more rapid. Use of ultrasound alone results in only 11% TOC removal in 60 min of treatment time. Addition of iron powder marginally enhances the extent of degradation but an appreciable increase is observed in the presence of hydrogen peroxide which acts as a source for hydroxyl radicals by Fenton chemistry as well as by dissociation in the presence of ultrasound. The use of hydrodynamic cavitation in conjunction with the advanced Fenton process has also been found to be a useful tool for continuous remediation of water contaminated with 2,4-D. After 20 min of treatment the residual TOC is reduced to 30% and this probably represents the remaining highly recalcitrant small organic molecules.

Photo-Fenton treatment of saccharin in a solar pilot compound parabolic collector: Use of olive mill wastewater as iron chelating agent, preliminary results.

PubMed

Davididou, K; Chatzisymeon, E; Perez-Estrada, L; Oller, I; Malato, S

2018-03-14

The aim of this work was to investigate the treatment of the artificial sweetener saccharin (SAC) in a solar compound parabolic collector pilot plant by means of the photo-Fenton process at pH 2.8. Olive mill wastewater (OMW) was used as iron chelating agent to avoid acidification of water at pH 2.8. For comparative purposes, Ethylenediamine-N, N-disuccinic acid (EDDS), a well-studied iron chelator, was also employed at circumneutral pH. Degradation products formed along treatment were identified by LC-QTOF-MS analysis. Their degradation was associated with toxicity removal, evaluated by monitoring changes in the bioluminescence of Vibrio fischeri bacteria. Results showed that conventional photo-Fenton at pH 2.8 could easily degrade SAC and its intermediates yielding k, apparent reaction rate constant, in the range of 0.64-0.82 L kJ -1 , as well as, eliminate effluent's chronic toxicity. Both OMW and EDDS formed iron-complexes able to catalyse H 2 O 2 decomposition and generate HO. OMW yielded lower SAC oxidation rates (k = 0.05-0.1 L kJ -1 ) than EDDS (k = 2.21-7.88 L kJ -1 ) possibly due to its higher TOC contribution. However, the degradation rates were improved (k = 0.13 L kJ -1 ) by increasing OMW dilution in the reactant mixture. All in all, encouraging results were obtained by using OMW as iron chelating agent, thus rendering this approach promising towards the increase of process sustainability. Copyright © 2018 Elsevier B.V. All rights reserved.

Fenton-like degradation of Bisphenol A catalyzed by mesoporous Cu/TUD-1

NASA Astrophysics Data System (ADS)

Pachamuthu, Muthusamy P.; Karthikeyan, Sekar; Maheswari, Rajamanickam; Lee, Adam F.; Ramanathan, Anand

2017-01-01

A family of copper oxide catalysts with loadings spanning 1-5 wt% were dispersed on a three dimensional, mesoporous TUD-1 silica through a hydrothermal, surfactant-free route employing tetraethylene glycol as a structure-directing agent. Their bulk and surface properties were characterized by N2 physisorption, XRD, DRUVS, EPR, TEM and Raman spectroscopy, confirming the expected mesoporous wormhole/foam support morphology and presence of well-dispersed CuO nanoparticles (∼5-20 nm). The catalytic performance of Cu/TUD-1 was evaluated as heterogeneous Fenton-like catalysts for Bisphenol A (BPA) oxidative degradation in the presence of H2O2 as a function of [H2O2], and CuO loading. Up to 90.4% of 100 ppm BPA removal was achieved over 2.5 wt% Cu/TUD-1 within 180 min, with negligible Cu leaching into the treated water.

Nano-jewels in biology. Gold and platinum on diamond nanoparticles as antioxidant systems against cellular oxidative stress.

PubMed

Martín, Roberto; Menchón, Cristina; Apostolova, Nadezda; Victor, Victor M; Alvaro, Mercedes; Herance, José Raúl; García, Hermenegildo

2010-11-23

Diamond nanoparticles (DNPs) obtained by explosive detonation have become commercially available. These commercial DNPs can be treated under Fenton conditions (FeSO(4) and H(2)O(2) at acidic pH) to obtain purer DNP samples with a small average particle size (4 nm) and a large population of surface OH groups (HO-DNPs). These Fenton-treated HO-DNPs have been used as a support of gold and platinum nanoparticles (≤2 nm average size). The resulting materials (Au/HO-DNP and Pt/HO-DNP) exhibit a high antioxidant activity against reactive oxygen species induced in a hepatoma cell line. In addition to presenting good biocompatibility, Au/HO- and Pt/HO-DNP exhibit about a two-fold higher antioxidant activity than glutathione, one of the reference antioxidant systems. The most active material against cellular oxidative stress was Au/HO-DNP.

Tertiary treatment of a municipal wastewater toward pharmaceuticals removal by chemical and electrochemical advanced oxidation processes.

PubMed

Moreira, Francisca C; Soler, J; Alpendurada, M F; Boaventura, Rui A R; Brillas, Enric; Vilar, Vítor J P

2016-11-15

This study focuses on the degradation of pharmaceuticals from a municipal wastewater after secondary treatment by applying various advanced oxidation processes (AOPs) and electrochemical AOPs (EAOPs) like UVC, H 2 O 2 /UVC, anodic oxidation (AO), AO with electrogenerated H 2 O 2 (AO-H 2 O 2 ), AO-H 2 O 2 /UVC and photoelectro-Fenton (PEF) using either UVC radiation (PEF-UVC) or UVA radiation (PEF-UVA). The municipal wastewater after secondary treatment was spiked with 5.0 mg L -1 of trimethoprim (TMP) antibiotic. The efficiency of processes to remove TMP followed the order UVC < AO-H 2 O 2  < PEF-UVA < AO ≈ PEF-UVC < AO-H 2 O 2 /UVC < PEF-UVA (pH = 2.8) < H 2 O 2 /UVC ≈ PEF-UVC (pH = 2.8), using neutral pH, except when identified. While the UVC radiation alone led to a very low TMP removal, the H 2 O 2 /UVC process promoted a very high TMP degradation due to the production of hydroxyl radicals (OH) by H 2 O 2 cleavage. In the AO-H 2 O 2 /UVC process, the electrogeneration of H 2 O 2 can avoid the risks associated with the transportation, storage and manipulation of this oxidant and, furthermore, OH at the anode surface are also formed. Nevertheless, low contents of H 2 O 2 were detected mainly at the beginning of the reaction, leading to a lower initial reaction rate when compared with the H 2 O 2 /UVC system. In the PEF-UVC, the addition of iron at neutral pH led to the visible formation of insoluble iron oxides that can filter the light. At pH 2.8, the iron remained dissolved, thereby promoting the Fenton's reaction and increasing the organics removal. The UVA-driven processes showed limited efficiency when compared with those using UVC light. For all processes with H 2 O 2 electrogeneration, the active chlorine species can be scavenged by the H 2 O 2 , diminishing the efficiency of the processes. This can explain the lower efficiency of AO-H 2 O 2 when compared with AO. Moreover, the degradation of the MWWTP effluent spiked with 18 pharmaceuticals in μg L -1 during AO process was assessed as well as the influence of the following operational variables on the process efficiency: (i) H 2 O 2 concentration on H 2 O 2 /UVC, (ii) current density on AO, AO-H 2 O 2 , AO-H 2 O 2 /UVC, PEF-UVC and PEF-UVA, and (iii) pH on PEF-UVA. Copyright © 2016 Elsevier Ltd. All rights reserved.

Concomitant degradation of bisphenol A during ultrasonication and Fenton oxidation and production of biofertilizer from wastewater sludge.

PubMed

Mohapatra, D P; Brar, S K; Tyagi, R D; Surampalli, R Y

2011-09-01

Degradation of bisphenol A (BPA), an endocrine disruptor, from wastewater sludge (WWS) has attracted great interest recently. In the present study, the effects of different pre-treatment methods, including ultrasonication (US), Fenton's oxidation (FO) and ferro-sonication (FS) was assessed in terms of increase in solubilization of WWS and simultaneous degradation of BPA. Among US, FO and FS pre-treatment, higher suspended solids (SS), volatile suspended solids (VSS), chemical oxygen demand (COD) and soluble organic carbon (SOC) solubilization (39.7%, 51.2%, 64.5% and 17.6%, respectively) was observed during a ferro-sonication pre-treatment process carried out for 180 min, resulting in higher degradation of BPA (82.7%). In addition, the effect of rheological parameters (viscosity and particle size) and zeta potential on the degradation of BPA in raw and different pre-treated sludges were also investigated. The results showed that a decrease in viscosity and particle size and an increase in zeta potential resulted in higher degradation of BPA. BPA degradation by laccases produced by Sinorhizobium meliloti in raw and pre-treated sludge was also determined. Higher activity of laccases (207.9 U L(-1)) was observed in ferro-sonicated pre-treated sludge (180 min ultrasonic time), resulting in higher removal of BPA (0.083 μg g(-1)), suggesting concomitant biological degradation of BPA. Copyright © 2011 Elsevier B.V. All rights reserved.

MEASUREMENT OF HYDROXYL RADICAL ACTIVITY IN A SOIL SLURRY USING THE SPIN TRAP A-(4-PYRIDYL-1-OXIDE)-N-TERT-BUTYLNITRONE

EPA Science Inventory

The spin trap compound a-(4-pyridyl-1-oxide)N-tert-butylnitrone (4-POBN) served as a probe to estimate the activity of Fenton-derived hydroxyl radicals (.OH) in a batch suspension comprised of silica sand and crushes goethite ore. The rate of probe disappearance was used to anal...

Application of Fenton process to remove organic matter and PCBs from waste (fuller's earth) contaminated with insulating oil.

PubMed

da Silva, Milady Renata Apolinário; Rodrigues, Eduardo de Oliveira; Espanhol-Soares, Melina; Silva, Flavio Soares; Kondo, Márcia Matiko; Gimenes, Rossano

2018-01-09

Polychlorinated biphenyls (PCBs) are carcinogenic to humans and can be found in fuller's earth used for the treatment of used transformer oil. This work describes an optimization of the Fenton process for the removal of contaminants from fuller's earth. The effects of pH (2.5 and 4.0), [H 2 O 2 ] (1.47 and 2.07 mol L -1 ), and [Fe 2+ ] (1.7 and 40 mmol L -1 ) were studied. The Fenton process efficiency was monitored using the decreases in the chemical oxygen demand (COD) and the concentrations of oil and grease, total carbon (TC), PCBs, and H 2 O 2 . The fuller's earth contaminated with insulating oil presented 35% (w/w) of TC, 34% (w/w) of oil and grease, 297.0 g L -1 COD, and 64 mg of PCBs per kg. The material could therefore be considered a dangerous waste. After Fenton treatment, using a slurry mode, there was a removal of 55% of COD, 20% of oil and grease, and 20% of TC, achieved at pH 2.5 using 2.07 mol L -1 of H 2 O 2 and 40.0 mmol L -1 of Fe 2+ . No PCBs were detected in the samples after the Fenton treatment, even using smaller amounts of Fenton reagents (1.47 mol L -1 of H 2 O 2 , 1.7 mmol L -1 of Fe 2+ , pH 2.5). The results indicated that the treated fuller's earth was free from PCB residues and could be disposed of in a simple landfill, in accordance with Brazilian PCB regulations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, Stefanie; Sommer, Anja; Distel, Luitpold V.R.

Highlights: Black-Right-Pointing-Pointer Ultrasmall citrate-coated SPIONs with {gamma}Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} structure were prepared. Black-Right-Pointing-Pointer SPIONs uptaken by MCF-7 cells increase the ROS production for about 240%. Black-Right-Pointing-Pointer The SPION induced ROS production is due to released iron ions and catalytically active surfaces. Black-Right-Pointing-Pointer Released iron ions and SPION surfaces initiate the Fenton and Haber-Weiss reaction. Black-Right-Pointing-Pointer X-ray irradiation of internalized SPIONs leads to an increase of catalytically active surfaces. -- Abstract: Internalization of citrate-coated and uncoated superparamagnetic iron oxide nanoparticles by human breast cancer (MCF-7) cells was verified by transmission electron microscopy imaging. Cytotoxicity studies employing metabolicmore » and trypan blue assays manifested their excellent biocompatibility. The production of reactive oxygen species in iron oxide nanoparticle loaded MCF-7 cells was explained to originate from both, the release of iron ions and their catalytically active surfaces. Both initiate the Fenton and Haber-Weiss reaction. Additional oxidative stress caused by X-ray irradiation of MCF-7 cells was attributed to the increase of catalytically active iron oxide nanoparticle surfaces.« less

Semicontinuous Fenton oxidation of phenol in aqueous solution. A kinetic study.

PubMed

Zazo, J A; Casas, J A; Mohedano, A F; Rodriguez, J J

2009-09-01

This work investigates the Fenton oxidation of phenol in a semicontinuous reactor where the overall amount of H(2)O(2) is distributed as a continuous feed upon the reaction time. The experiments were carried out at 25 degrees C and atmospheric pressure, with 100mg/L initial phenol concentration and iron dosages from 1 to 100 mg/L. H(2)O(2) aqueous solution was continuously fed during 4h reaction time up to an overall dose varying within the range of 500-5000 mg/L. The results in terms of evolution of phenol, H(2)O(2) and intermediates, as well as TOC abatement were compared with those obtained in conventional batch operation. It was found that the oxidation rates for phenol and intermediates were lower when adding the H(2)O(2) continuously. However, a higher abatement of TOC was reached at the end of the 4-h reaction time, in spite of a similar overall H(2)O(2) consumption. This is the result of a more efficient OH generation throughout the semicontinuous process, favouring the reaction with the organic species and reducing the occurrence of competitive scavenging reactions involving Fe(2+), H(2)O(2) and OH. Two kinetic models were proposed, one for describing the evolution of phenol, aromatics and H(2)O(2) and the other for TOC. The influence of the operating conditions on the kinetic constants was also studied, looking for the optimal conditions in terms of both, environmental and economic points of view.

The oxidative hypothesis of senescence.

PubMed

Gilca, M; Stoian, I; Atanasiu, V; Virgolici, B

2007-01-01

The oxidative hypothesis of senescence, since its origin in 1956, has garnered significant evidence and growing support among scientists for the notion that free radicals play an important role in ageing, either as "damaging" molecules or as signaling molecules. Age-increasing oxidative injuries induced by free radicals, higher susceptibility to oxidative stress in short-lived organisms, genetic manipulations that alter both oxidative resistance and longevity and the anti-ageing effect of caloric restriction and intermittent fasting are a few examples of accepted scientific facts that support the oxidative theory of senescence. Though not completely understood due to the complex "network" of redox regulatory systems, the implication of oxidative stress in the ageing process is now well documented. Moreover, it is compatible with other current ageing theories (e.g, those implicating the mitochondrial damage/mitochondrial-lysosomal axis, stress-induced premature senescence, biological "garbage" accumulation, etc). This review is intended to summarize and critically discuss the redox mechanisms involved during the ageing process: sources of oxidant agents in ageing (mitochondrial -electron transport chain, nitric oxide synthase reaction- and non-mitochondrial- Fenton reaction, microsomal cytochrome P450 enzymes, peroxisomal beta -oxidation and respiratory burst of phagocytic cells), antioxidant changes in ageing (enzymatic- superoxide dismutase, glutathione-reductase, glutathion peroxidase, catalase- and non-enzymatic glutathione, ascorbate, urate, bilirubine, melatonin, tocopherols, carotenoids, ubiquinol), alteration of oxidative damage repairing mechanisms and the role of free radicals as signaling molecules in ageing.

Treatment of municipal wastewater treatment plant effluents with modified photo-Fenton as a tertiary treatment for the degradation of micro pollutants and disinfection.

PubMed

Klamerth, Nikolaus; Malato, Sixto; Agüera, Ana; Fernández-Alba, Amadeo; Mailhot, Gilles

2012-03-06

The goal of this paper was to develop a modified photo-Fenton treatment able to degrade micro pollutants in municipal wastewater treatment plant (MWTP) effluents at a neutral pH with minimal iron and H(2)O(2) concentrations. Complexation of Fe by ethylenediamine-N,N'-disuccinic acid (EDDS) leads to stabilization and solubilization of Fe at natural pH. Photo-Fenton experiments were performed in a pilot compound parabolic collector (CPC) solar plant. Samples were treated with solid phase extraction (SPE) and analyzed by HPLC-Qtrap-MS. The rapid degradation of contaminants within the first minutes of illumination and the low detrimental impact on degradation of bicarbonates present in the water suggested that radical species other than HO(•) are responsible for the efficiency of such photo-Fenton process. Disinfection of MWTP effluents by the same process showed promising results, although disinfection was not complete.

Hydroxylamine Promoted Goethite Surface Fenton Degradation of Organic Pollutants.

PubMed

Hou, Xiaojing; Huang, Xiaopeng; Jia, Falong; Ai, Zhihui; Zhao, Jincai; Zhang, Lizhi

2017-05-02

In this study, we construct a surface Fenton system with hydroxylamine (NH 2 OH), goethite (α-FeOOH), and H 2 O 2 (α-FeOOH-HA/H 2 O 2 ) to degrade various organic pollutants including dyes (methyl orange, methylene blue, and rhodamine B), pesticides (pentachlorophenol, alachlor, and atrazine), and antibiotics (tetracycline, chloramphenicol, and lincomycin) at pH 5.0. In this surface Fenton system, the presence of NH 2 OH could greatly promote the H 2 O 2 decomposition on the α-FeOOH surface to produce ·OH without releasing any detectable iron ions during the alachlor degradation, which was different from some previously reported heterogeneous Fenton counterparts. Moreover, the ·OH generation rate constant of this surface Fenton system was 10 2 -10 4 times those of previous heterogeneous Fenton processes. The interaction between α-FeOOH and NH 2 OH was investigated with using attenuated total reflectance Fourier transform infrared spectroscopy and density functional theory calculations. The effective degradation of organic pollutants in this surface Fenton system was ascribed to the efficient Fe(III)/Fe(II) cycle on the α-FeOOH surface promoted by NH 2 OH, which was confirmed by X-ray photoelectron spectroscopy analysis. The degradation intermediates and mineralization of alachlor in this surface Fenton system were then systematically investigated using total organic carbon and ion chromatography, liquid chromatography-mass spectrometry, and gas chromatography-mass spectrometry. This study offers a new strategy to degrade organic pollutants and also sheds light on the environmental effects of goethite.

The removal of low level inorganics via electrogenerated hydrogen peroxide in the presence of catalytic amounts of Fe2+.

PubMed

Marrosu, G; Petrucci, R; Trazza, A

2001-01-01

Low level phosphites and hypophosphites were completely converted into phosphates, via hydrogen peroxide generated by cathodic reduction of oxygen in acidic aqueous medium at a reticulated vitreous carbon electrode, in the presence of little amounts of Fe2+. The contemporary regeneration of Fe2+ by cathodic reduction of Fe3+, produced by the well known Fenton reaction, furnishes an excellent way to continuously produce little amounts of the Fenton reactive and, as a consequence, of the powerful oxidant hydroxyl radical HO.. The best conditions for the complete removal of phosphorous as phosphites and hypophosphites are reported.

Alkaline electrochemical advanced oxidation process for chromium oxidation at graphitized multi-walled carbon nanotubes.

PubMed

Xue, Yudong; Zheng, Shili; Sun, Zhi; Zhang, Yi; Jin, Wei

2017-09-01

Alkaline electrochemical advanced oxidation processes for chromium oxidation and Cr-contaminated waste disposal were reported in this study. The highly graphitized multi-walled carbon nanotubes g-MWCNTs modified electrode was prepared for the in-situ electrochemical generation of HO 2 - . RRDE test results illustrated that g-MWCNTs exhibited much higher two-electron oxygen reduction activity than other nanocarbon materials with peak current density of 1.24 mA cm -2 , %HO 2 - of 77.0% and onset potential of -0.15 V (vs. Hg/HgO). It was originated from the highly graphitized structure and good electrical conductivity as illustrated from the Raman, XRD and EIS characterizations, respectively. Large amount of reactive oxygen species (HO 2 - and ·OH) were in-situ electro-generated from the two-electron oxygen reduction and chromium-induced alkaline electro-Fenton-like reaction. The oxidation of Cr(III) was efficiently achieved within 90 min and the conversion ratio maintained more than 95% of the original value after stability test, offering an efficient and green approach for the utilization of Cr-containing wastes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Catalytic Properties of Fe-containing Layered Aluminosilicates in Photo-oxidation of Dye “Methyl Green”

NASA Astrophysics Data System (ADS)

Shadrina, O. A.; Dashinamzhilova, E. Ts; Khankhasaeva, S. Ts

2017-11-01

The iron-containing materials with an iron content of 40 mg/g and 52.5 mg/g, a specific surface area of 107 m2/g and 96 m2/g are developed on the basis of natural layered aluminosilicate (montmorillonite) and polyhydroxo complexes of iron. It is shown that the materials exhibit high catalytic activity in the photo-oxidation of dye “Methyl Green”. The influence of physicochemical parameters (loading of the catalyst, a ratio of initial concentrations [H2O2]/[MG] on the efficiency of the dye photo-oxidation was established. The optimum conditions, which made it possible to achieve high mineralization and 100 % the dye oxidation efficiency were determined: the catalyst loading equal to 1.0 g/l and the ratio of [H2O2] and [MG] equal to stoichiometric ratio (55 mol/mol). The decrease of the total organic carbon content after photo-oxidation reaction was 56.5%. The average value of the quantum yield of the dye photo-oxidation was to 0.30 mol/Einstein. The results of the conducted research show that the developed iron-containing materials are the promising catalysts for photo-Fenton processes of oxidative degradation of organic compounds. The materials are of interest for use in wastewater treatment processes from toxic organic pollutants.

Nanocasted synthesis of magnetic mesoporous iron cerium bimetal oxides (MMIC) as an efficient heterogeneous Fenton-like catalyst for oxidation of arsenite.

PubMed

Wen, Zhipan; Zhang, Yalei; Dai, Chaomeng; Sun, Zhen

2015-04-28

Magnetic mesoporous iron cerium bimetal oxides (MMIC) with large surface area and pore volume was synthesized via the hard template approach. This obtained MMIC was easily separated from aqueous solution with an external magnetic field and was proposed as a heterogeneous Fenton-like catalyst for oxidation of As(III). The MMIC presented excellent catalytic activity for the oxidation of As(III), achieving almost complete oxidation of 1000ppb As(III) after 60min and complete removal of arsenic species after 180min with reaction conditions of 0.4g/L catalyst, pH of 3.0 and 0.4mM H2O2. Kinetics analysis showed that arsenic removal followed the pseudo-first order, and the pseudo-first-order rate constants increased from 0.0014min(-1) to 0.0548min(-1) as the H2O2 concentration increased from 0.04mM to 0.4mM. On the basis of the effects of XPS analysis and reactive oxidizing species, As(III) in aqueous solution was mainly oxidized by OH radicals, including the surface-bound OHads generated on the MMIC surface which were involved in Fe(2+) and Ce(3+), and free OHfree generation by soluble iron ions which were released from the MMIC into the bulk solution, and the generated As(V) was finally removed by MMIC through adsorption. Copyright © 2015 Elsevier B.V. All rights reserved.

Partial degradation of levofloxacin for biodegradability improvement by electro-Fenton process using an activated carbon fiber felt cathode.

PubMed

Gong, Yuexiang; Li, Jiuyi; Zhang, Yanyu; Zhang, Meng; Tian, Xiujun; Wang, Aimin

2016-03-05

Solutions of 500 mL 200 mg L(-1) fluoroquinolone antibiotic levofloxacin (LEVO) have been degraded by anodic oxidation (AO), AO with electrogenerated H2O2 (AO-H2O2) and electro-Fenton (EF) processes using an activated carbon fiber (ACF) felt cathode from the point view of not only LEVO disappearance and mineralization, but also biodegradability enhancement. The LEVO decay by EF process followed a pseudo-first-order reaction with an apparent rate constant of 2.37×10(-2)min(-1), which is much higher than that of AO or AO-H2O2 processes. The LEVO mineralization also evidences the order EF>AO-H2O2>AO. The biodegradability (BOD5/COD) increased from 0 initially to 0.24, 0.09, and 0.03 for EF, AO-H2O2 and AO processes after 360 min treatment, respectively. Effects of several parameters such as current density, initial pH and Fe(2+) concentration on the EF degradation have also been examined. Three carboxylic acids including oxalic, formic and acetic acid were detected, as well as the released inorganic ions NH4(+), NO3(-) and F(-). At last, an ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry was used to identify about eight aromatic intermediates formed in 60 min of EF treatment, and a plausible mineralization pathway for LEVO by EF treatment was proposed. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of combined physico-chemical processes on the phytotoxicity of olive mill wastewaters.

PubMed

Andreozzi, Roberto; Canterino, Marisa; Di Somma, Ilaria; Lo Giudice, Roberto; Marotta, Raffaele; Pinto, Gabriele; Pollio, Antonino

2008-03-01

A pool of laboratory experiments is planned with the aim of evaluating the possibility to reduce the phytotoxicity of olive mill wastewater (OMW) with combined physico-chemical processes (centrifugation-ozonation, centrifugation-solar photolysis, centrifugation-solar modified photoFenton, centrifugation-solar modified photoFenton-ozonation). A moderate COD removal of an OMW is reached by using ozonation or solar modified photoFenton separately or solar modified photoFenton/O(3) combined process even for prolonged treatment times. The O(3)-treated OMWs are still toxic towards algal growth (Pseudokirchneriella subcapitata) and only for dilutions equal to or higher than 1:160 a stimulation of algal growth is observed. The sole ozonation does not reduce significantly the phytotoxicity of tested OMW measured through the GI calculation of Raphanus sativus L., Cucumis sativus L. and Lactuca sativa L. A marked reduction of OMW inhibition, higher than 50%, is evidenced for 1:8 dilution OMW samples ozonated for 2h. The long-term storage of OMW associated with solar irradiation without or with Fe(III) ions under continuous aeration is less efficient than ozonation, and the combined action of the two former treatments does not significantly contribute to enhance both COD removal and germination index. Better results are obtained on seed germination and root elongation of plantlets of the three selected species, which germinated on OMW-free solidified medium and were then transferred on a solidified culture medium containing O(3)-treated OMW diluted 1:2 and 1:4. The operating costs are estimated for the solar modified photoFenton-ozonation process.