Demonstration of the Fenton Reaction

ERIC Educational Resources Information Center

Luehrs, Dean C.; Roher, Alex E.

2007-01-01

The study demonstrates the Fenton reaction, which is carried out using the Fenton reagent that is used for groundwater and soil remediation. The Fenton reaction can be implicated in DNA damage, Alzheimer's disease, cardiovascular disease and ageing in general.

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.

Chlorbromuron urea herbicide removal by electro-Fenton reaction in aqueous effluents.

PubMed

Martínez, Susana Silva; Bahena, Cristina Lizama

2009-01-01

The removal of low concentration of chlorbromuron herbicide in aqueous systems was carried out by electro-Fenton process comprised of three-electrode divided and undivided cell with a reticulated vitreous carbon cathode and platinum anode. The electro-Fenton was also carried out in a two-electrode undivided cell in which ferrous ion forms from a sacrificial iron anode. It was observed that the total organic carbon (TOC) removal efficiency was influenced by the cell voltage, the pH of the solution and initial herbicide concentration during the electro-Fenton treatment with a stainless steel anode. The Fe(2+)/Fe(3+) activity in the Fenton chemistry (regardless if it is hydroxyl radical or ferryl ion) was improved by the electrochemical catalysis leading to a TOC analysis below the detection limit (0.2 mg l(-1)) corresponding to a TOC removal over 98%. It was found that TOC removal during chlorbromuron degradation followed apparent first order kinetics. The rate constant was increased by decreasing the initial concentration of chlorbromuron.

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.

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).

Synergetic Effect of Ultrasound, the Heterogeneous Fenton Reaction and Photocatalysis by TiO2 Loaded on Nickel Foam on the Degradation of Pollutants

PubMed Central

Qiu, Shan; Xu, Shanwen; Li, Guangming; Yang, Jixian

2016-01-01

The synergistic effect of ultrasound, the heterogeneous Fenton reaction and photocatalysis was studied using a nickel foam (NF)-supporting TiO2 system and rhodamine B (RhB) as a target. The NF-supporting TiO2 system was prepared by depositing TiO2 on the skeleton of NF repeatedly and then calcining it. To optimize the conditions and parameters, the catalytic activity was tested in four systems (ultrasound alone (US), nickel foam (NF), US/NF and NF/US/H2O2). The optimal conditions were fixed at 0.1 g/mL NF, initial 5.00 mg/L RhB, 300 W ultrasonic power, pH = 3 and 5.00 mg/L H2O2. The effects of the dissolution of nickel from NF and quenching of the Fenton reaction were studied on degradation efficiency. When the heterogeneous Fenton reaction is combined with TiO2-photocatalysis, the pollutant removal efficiency is enhanced significantly. Through this synergistic effect, 22% and 80% acetochlor was degraded within 10 min and 80 min, respectively. PMID:28773580

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.

Tunable, Quantitative Fenton-RAFT Polymerization via Metered Reagent Addition.

PubMed

Nothling, Mitchell D; McKenzie, Thomas G; Reyhani, Amin; Qiao, Greg G

2018-05-10

A continuous supply of radical species is a key requirement for activating chain growth and accessing quantitative monomer conversions in reversible addition-fragmentation chain transfer (RAFT) polymerization. In Fenton-RAFT, activation is provided by hydroxyl radicals, whose indiscriminate reactivity and short-lived nature poses a challenge to accessing extended polymerization times and quantitative monomer conversions. Here, an alternative Fenton-RAFT procedure is presented, whereby radical generation can be finely controlled via metered dosing of a component of the Fenton redox reaction (H 2 O 2 ) using an external pumping system. By limiting the instantaneous flux of radicals and ensuring sustained radical generation over tunable time periods, metered reagent addition reduces unwanted radical "wasting" reactions and provides access to consistent quantitative monomer conversions with high chain-end fidelity. Fine tuning of radical concentration during polymerization is achieved simply via adjustment of reagent dose rate, offering significant potential for automation. This modular strategy holds promise for extending traditional RAFT initiation toward more tightly regulated radical concentration profiles and affords excellent prospects for the automation of Fenton-RAFT polymerization. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Advancing Fenton and photo-Fenton water treatment through the catalyst design.

PubMed

Vorontsov, Alexander V

2018-04-20

The review is devoted to modern Fenton, photo-Fenton, as well as Fenton-like and photo-Fenton-like reactions with participation of iron species in liquid phase and as heterogeneous catalysts. Mechanisms of these reactions were considered that include hydroxyl radical and oxoferryl species as the reactive intermediates. The barriers in the way of application of these reactions to wastewater treatment were discussed. The following fundamental problems need further research efforts: inclusion of more mechanism steps and quantum calculations of all rate constants lacking in the literature, checking the outer sphere electron transfer contribution, determination of the causes for the key changes in the homogeneous Fenton reaction mechanism with a change in the reagents concentration. The key advances for Fenton reactions implementation for the water treatment are related to tremendous hydrodynamical effects on the catalytic activity, design of ligands for high rate and completeness of mineralization in short time, and design of highly active heterogeneous catalysts. While both homogeneous and heterogeneous Fenton and photo-Fenton systems are open for further improvements, heterogeneous photo-Fenton systems are most promising for practical applications because of the inherent higher catalyst stability. Modern methods of quantum chemistry are expected to play a continuously increasing role in development of such catalysts. Copyright © 2018 Elsevier B.V. All rights reserved.

Development of a system for treatment of coconut industry wastewater using electrochemical processes followed by Fenton reaction.

PubMed

Gomes, Lúcio de Moura; Duarte, José Leandro da Silva; Pereira, Nathalia Marcelino; Martínez-Huitle, Carlos A; Tonholo, Josealdo; Zanta, Carmen Lúcia de Paiva E Silva

2014-01-01

The coconut processing industry generates a significant amount of liquid waste. New technologies targeting the treatment of industrial effluents have emerged, including advanced oxidation processes, the Fenton reaction, and electrochemical processes, which produce strong oxidizing species to remove organic matter. In this study we combined the Fenton reaction and electrochemical process to treat wastewater generated by the coconut industry. We prepared a synthetic wastewater consisting of a mixture of coconut milk and water and assessed how the Fenton reagents' concentration, the cathode material, the current density, and the implementation of associated technologies affect its treatment. Electrochemical treatment followed by the Fenton reaction diminished turbidity and chemical oxygen demand (COD) by 85 and 95%, respectively. The Fenton reaction followed by the electrochemical process reduced turbidity and COD by 93 and 85%, respectively. Therefore, a combination of the Fenton and electrochemical technologies can effectively treat the effluent from the coconut processing industry.

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.

Sequential application of Fenton and ozone-based oxidation process for the abatement of Ni-EDTA containing nickel plating effluents.

PubMed

Zhao, Zilong; Liu, Zekun; Wang, Hongjie; Dong, Wenyi; Wang, Wei

2018-07-01

Treatment of Ni-EDTA in industrial nickel plating effluents was investigated by integrated application of Fenton and ozone-based oxidation processes. Determination of integrated sequence found that Fenton oxidation presented higher apparent kinetic rate constant of Ni-EDTA oxidation and capacity for contamination load than ozone-based oxidation process, the latter, however, was favorable to guarantee the further mineralization of organic substances, especially at a low concentration. Serial-connection mode of two oxidation processes was appraised, Fenton effluent after treated by hydroxide precipitation and filtration negatively affected the overall performance of the sequential system, as evidenced by the removal efficiencies of Ni 2+ and TOC dropping from 99.8% to 98.7%, and from 74.8% to 66.6%, respectively. As a comparison, O 3 /Fe 2+ oxidation process was proved to be more effective than other processes (e.g. O 3 -Fe 2+ , O 3 /H 2 O 2 /Fe 2+ , O 3 /H 2 O 2 -Fe 2+ ), and the final effluent Ni 2+ concentration could satisfied the discharge standard (<0.1 mg L -1 , China) under the optimal conditions (H 2 O 2 dosage of 1.0 mL L -1 , Fe 2+ : H 2 O 2 mole ratio of 1.46, and reaction time of 10 min for Fenton reaction, initial influent pH of 3.0, O 3 dosage of 252 mg L -1 , Fe 2+ of 150 mg L -1 , and reaction time of 30 min for O 3 /Fe 2+ oxidation). Furthermore, pilot-scale test was carried out to study the practical treatability towards the real nickel plating effluent, revealing the effective removal of some other co-existence contaminations. And Fenton reaction has contributed most, with the percentage ranging from 72.41% to 93.76%. The economic cost advantage made it a promising alternative to the continuous Fenton oxidation. Copyright © 2018 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

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.

Hepatitis A Virus Disinfection in Water by Solar Photo-Fenton Systems.

PubMed

Polo, David; García-Fernández, Irene; Fernández-Ibañez, Pilar; Romalde, Jesús L

2018-06-01

This study evaluates and compares the effectiveness of solar photo-Fenton systems for the inactivation of hepatitis A virus (HAV) in water. The effect of solar irradiance, dark- Fenton reaction and three different reactant concentrations (2.5/5, 5/10 and 10/20 mg/L of Fe 2+ /H 2 O 2 ) on the photo-Fenton process were tested in glass bottle reactors (200 mL) during 6 h under natural sunlight. Disinfection kinetics were determined both by RT-qPCR and infectivity assays. Mean water temperatures ranged from 25 to 27.3 °C, with a maximum local noon UV irradiances of 22.36 W/m 2 . Photo-Fenton systems yielded increased viral reduction rates in comparison with the isolated effect under the Fenton reaction in darkness (negligible viral reduction) or the solar radiation (0.25 Log of RNA reduction). With the highest concentration employed (10-20 mg/L Fe 2+ -H 2 O 2 ), an average RNA reduction rate of ~ 1.8 Log (initial concentration of 10 5 pfu/mL) and a reduction of 80% in the infectivity capacity were reached. Results showed a strong synergistic effect between Fe 2+ /H 2 O 2 and sunlight, demonstrating that significant disinfection rates of HAV under photo-Fenton systems may occur with relatively higher efficiency at middle environmental temperatures and without the need for an energy-intensive light source.

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.

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.

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

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.

Simultaneous Transformation of Commingled Trichloroethylene, Tetrachloroethylene, and 1,4-Dioxane by a Microbially Driven Fenton Reaction in Batch Liquid Cultures.

PubMed

Sekar, Ramanan; Taillefert, Martial; DiChristina, Thomas J

2016-11-01

Improper disposal of 1,4-dioxane and the chlorinated organic solvents trichloroethylene (TCE) and tetrachloroethylene (also known as perchloroethylene [PCE]) has resulted in widespread contamination of soil and groundwater. In the present study, a previously designed microbially driven Fenton reaction system was reconfigured to generate hydroxyl (HO˙) radicals for simultaneous transformation of source zone levels of single, binary, and ternary mixtures of TCE, PCE, and 1,4-dioxane. The reconfigured Fenton reaction system was driven by fed batch cultures of the Fe(III)-reducing facultative anaerobe Shewanella oneidensis amended with lactate, Fe(III), and contaminants and exposed to alternating anaerobic and aerobic conditions. To avoid contaminant loss due to volatility, the Fe(II)-generating, hydrogen peroxide-generating, and contaminant transformation phases of the microbially driven Fenton reaction system were separated. The reconfigured Fenton reaction system transformed TCE, PCE, and 1,4-dioxane either as single contaminants or as binary and ternary mixtures. In the presence of equimolar concentrations of PCE and TCE, the ratio of the experimentally derived rates of PCE and TCE transformation was nearly identical to the ratio of the corresponding HO˙ radical reaction rate constants. The reconfigured Fenton reaction system may be applied as an ex situ platform for simultaneous degradation of commingled TCE, PCE, and 1,4-dioxane and provides valuable information for future development of in situ remediation technologies. A microbially driven Fenton reaction system [driven by the Fe(III)-reducing facultative anaerobe S. oneidensis] was reconfigured to transform source zone levels of TCE, PCE, and 1,4-dioxane as single contaminants or as binary and ternary mixtures. The microbially driven Fenton reaction may thus be applied as an ex situ platform for simultaneous degradation of at least three (and potentially more) commingled contaminants. Additional targets for ex situ and in situ degradation by the microbially driven Fenton reaction developed in the present study include multiple combinations of environmental contaminants susceptible to attack by Fenton reaction-generated HO˙ radicals, including commingled plumes of 1,4-dioxane, pentachlorophenol (PCP), PCE, TCE, 1,1,2-trichloroethane (TCA), and perfluoroalkylated substances (PFAS). Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Simultaneous Transformation of Commingled Trichloroethylene, Tetrachloroethylene, and 1,4-Dioxane by a Microbially Driven Fenton Reaction in Batch Liquid Cultures

PubMed Central

Sekar, Ramanan; Taillefert, Martial

2016-01-01

ABSTRACT Improper disposal of 1,4-dioxane and the chlorinated organic solvents trichloroethylene (TCE) and tetrachloroethylene (also known as perchloroethylene [PCE]) has resulted in widespread contamination of soil and groundwater. In the present study, a previously designed microbially driven Fenton reaction system was reconfigured to generate hydroxyl (HO˙) radicals for simultaneous transformation of source zone levels of single, binary, and ternary mixtures of TCE, PCE, and 1,4-dioxane. The reconfigured Fenton reaction system was driven by fed batch cultures of the Fe(III)-reducing facultative anaerobe Shewanella oneidensis amended with lactate, Fe(III), and contaminants and exposed to alternating anaerobic and aerobic conditions. To avoid contaminant loss due to volatility, the Fe(II)-generating, hydrogen peroxide-generating, and contaminant transformation phases of the microbially driven Fenton reaction system were separated. The reconfigured Fenton reaction system transformed TCE, PCE, and 1,4-dioxane either as single contaminants or as binary and ternary mixtures. In the presence of equimolar concentrations of PCE and TCE, the ratio of the experimentally derived rates of PCE and TCE transformation was nearly identical to the ratio of the corresponding HO˙ radical reaction rate constants. The reconfigured Fenton reaction system may be applied as an ex situ platform for simultaneous degradation of commingled TCE, PCE, and 1,4-dioxane and provides valuable information for future development of in situ remediation technologies. IMPORTANCE A microbially driven Fenton reaction system [driven by the Fe(III)-reducing facultative anaerobe S. oneidensis] was reconfigured to transform source zone levels of TCE, PCE, and 1,4-dioxane as single contaminants or as binary and ternary mixtures. The microbially driven Fenton reaction may thus be applied as an ex situ platform for simultaneous degradation of at least three (and potentially more) commingled contaminants. Additional targets for ex situ and in situ degradation by the microbially driven Fenton reaction developed in the present study include multiple combinations of environmental contaminants susceptible to attack by Fenton reaction-generated HO˙ radicals, including commingled plumes of 1,4-dioxane, pentachlorophenol (PCP), PCE, TCE, 1,1,2-trichloroethane (TCA), and perfluoroalkylated substances (PFAS). PMID:27542932

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.

Use of photo-Fenton's reaction by 400-nm LED light for endodontic disinfection: A preliminary in vitro study on Enterococcus faecalis.

PubMed

Lagori, Giuseppe; Fornaini, Carlo; Rocca, Jean-Paul; Merigo, Elisabetta

2017-06-01

One of the biggest challenges in endodontics is the complete disinfection of root canals. In addition to mechanical preparation, the technique traditionally also involves channel disinfection with other agents such as sodium hypochlorite, hydrogen peroxide, chlorhexidine, or a combination of these. Some bacterial species are particularly resistant to eradication. Using Enterococcus faecalis in this preliminary study, we tested the bactericidal effectiveness of the Fenton reaction and the photo-Fenton reaction using an LED light with a 400-nm wavelength. Discs of hydroxyapatite were incubated in brain-heart broth contaminated with Enterococcus faecalis. After 4days, they were decontaminated with different bactericidal agents, including some with proven and well-known efficacy (5% sodium hypochlorite and 3% hydrogen peroxide) and other treatments using solutions of 1.5% hydrogen peroxide and 0.15% iron gluconate (Fenton reaction) plus LED light at a Fluence of 4.0J/cm 2 (photo-Fenton reaction). The photo-Fenton reaction demonstrated comparable performance to that of sodium hypochlorite in eliminating Enterococcus faecalis. Copyright © 2017. Published by Elsevier B.V.

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.

Novel bio-electro-Fenton technology for azo dye wastewater treatment using microbial reverse-electrodialysis electrolysis cell.

PubMed

Li, Xiaohu; Jin, Xiangdan; Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

2017-03-01

Development of sustainable technologies for treatment of azo dyes containing wastewaters has long been of great interest. In this study, we proposed an innovative concept of using microbial reverse-electrodialysis electrolysis cell (MREC) based Fenton process to treat azo dye wastewater. In such MREC-Fenton integrated process, the production of H 2 O 2 which is the key reactant of fenton-reaction was driven by the electrons harvested from the exoelectrogens and salinity-gradient between sea water and fresh water in MREC. Complete decolorization and mineralization of 400mgL -1 Orange G was achieved with apparent first order rate constants of 1.15±0.06 and 0.26±0.03h -1 , respectively. Furthermore, the initial concentration of orange G, initial solution pH, catholyte concentration, high and low concentration salt water flow rate and air flow rate were all found to significantly affect the dye degradation. This study provides an efficient and cost-effective system for the degradation of non-biodegradable pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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.

Degradation of 4-Chloro-3,5-Dimethylphenol by a Heterogeneous Fenton-Like Reaction Using Nanoscale Zero-Valent Iron Catalysts

PubMed Central

Xu, Lejin; Wang, Jianlong

2013-01-01

Abstract Degradation of 4-chloro-3,5-dimethylphenol (PCMX) by a heterogeneous Fenton-like process using nanoparticulate zero-valent iron (nZVI) and hydrogen peroxide (H2O2) at pH 6.3 was investigated. Interactive effects of three factors—initial PCMX concentration, nZVI dosage, and H2O2 concentration—were investigated using the response surface method based on the Box–Behnken design. Experimental results showed that complete decomposition of PCMX and 65% of total organic carbon removal were observed after 30 min of reaction at neutral pH under recommended reaction conditions: nZVI, 1.0 g/L; H2O2, 18 mM; and initial PCMX concentration, 0.15 g/L. Based on the effects of scavengers n-butanol and KI, removal of PCMX was mainly attributed to the attack of •OH, especially the surface-bonded •OH. A possible degradation pathway of PCMX was proposed. PMID:23781127

In Vivo Lighted Fluorescence via Fenton Reaction: Approach for Imaging of Hydrogen Peroxide in Living Systems.

PubMed

Liu, Changhui; Chen, Weiju; Qing, Zhihe; Zheng, Jing; Xiao, Yue; Yang, Sheng; Wang, Lili; Li, Yinhui; Yang, Ronghua

2016-04-05

By virtue of its high sensitivity and rapidity, Fenton reaction has been demonstrated as a powerful tool for in vitro biochemical analysis; however, in vivo applications of Fenton reaction still remain to be exploited. Herein, we report, for the first time, the design, formation and testing of Fenton reaction for in vivo fluorescence imaging of hydrogen peroxide (H2O2). To realize in vivo fluorescence imaging of H2O2 via Fenton reaction, a functional nanosphere, Fc@MSN-FDNA/PTAD, is fabricated from mesoporous silica nanoparticle (MSN), a Fenton reagent of ferrocene (Fc), ROX-labeled DNA (FDNA), and a cationic perylene derivative (PTAD). The ferrocene molecules are locked in the pore entrances of MSN, and exterior of MSN is covalently immobilized with FDNA. As a key part, PTAD acts as not only the gatekeeper of MSN but also the efficient quencher of ROX. H2O2 can permeate into the nanosphere and react with ferrocene to product hydroxyl radical (·OH) via Fenton reaction, which cleaves FDNA to detach ROX from PTAD, thus in turn, lights the ROX fluorescence. Under physiological condition, H2O2 can be determined from 5.0 nM to 1.0 μM with a detection limit of 2.4 nM. Because of the rapid kinetics of Fenton reaction and high specificity for H2O2, the proposed method meets the requirement for real applications. The feasibility of Fc@MSN-FDNA/PTAD for in vivo applications is demonstrated for fluorescence imaging of exogenous and endogenous H2O2 in cells and mice. We expect that this work will not only contribute to the H2O2-releated studies but also open up a new way to exploit in vivo Fenton reaction for biochemical research.

Degradation and detoxification of 4-nitrophenol by advanced oxidation technologies and bench-scale constructed wetlands.

PubMed

Herrera-Melián, J A; Martín-Rodríguez, A J; Ortega-Méndez, A; Araña, J; Doña-Rodríguez, J M; Pérez-Peña, J

2012-08-30

The degradation and detoxification towards the duckweed Lemna minor of 4-nitrophenol (4NP) was studied by means of bench-scale constructed wetlands (CWs), TiO(2)-photocatalysis and Fenton + photoFenton reactions. The main goal of this work was to compare the three treatment techniques to evaluate their possible combination for the efficient, low cost treatment of 4NP effluents. In CWs, adsorption on the substrate of 4NP was found to achieve 34-45%. Low concentrations (up to 100 ppm) of 4NP were successfully treated by CWs in 8-12 h. The microbial degradation of 4NP started after a lag phase which was longer with higher initial concentrations of the pollutant. The greatest degradation rate was found to occur at initial concentrations of 4NP between 60 and 90 ppm. Solar TiO(2)-photocatalysis was faster than the CWs. The greatest removals in terms of mass of 4NP removed after 6 h of irradiation were found to occur at 4NP concentrations of about 200 ppm. Fenton reaction provided complete 4NP degradation up to 500 ppm in only 30 min but TOC was removed by only about 40%. The resulting toxicities were below 20% for initial 4NP concentrations below 300 ppm. It was the Fenton + photoFenton combination (180 min in total) that provided TOC reductions up to 80% and negative L. minor growth inhibition for almost all the 4NP concentrations tested. The combination of solar TiO(2)-photocatalysis (6 h) with CWs (16 h) was able to completely treat and detoxify 4NP effluents with concentrations as high as 200 ppm of the organic. Copyright © 2012 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.

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.

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.

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.

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.

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.

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.

VUV/UV light inducing accelerated phenol degradation with a low electric input.

PubMed

Li, Mengkai; Wen, Dong; Qiang, Zhimin; Kiwi, John

2017-01-23

This study presents the first evidence for the accelerated degradation of phenol by Fenton's reagent in a mini-fluidic VUV/UV photoreaction system (MVPS). A low-pressure mercury lamp used in the MVPS led to a complete degradation of phenol within 4-6 min. The HO˙ and HO 2 ˙ originating from both Fenton's reagent and VUV photolysis of water were identified with suitable radical scavengers. The effects of initial concentrations of phenol, H 2 O 2 and Fe 3+ as well as solution pH on phenol degradation kinetics were examined. Increasing the initial phenol concentration slowed down the phenol degradation, whereas increasing the initial H 2 O 2 or Fe 3+ concentration accelerated the phenol degradation. The optimal solution pH was 3.7. At both 254 and 185 nm, increasing phenol concentration enhanced its absorption for the incident photons. The reaction mechanism for the degradation of phenol was suggested consistent with the results obtained. This study indicates that the VUV/UV photo-Fenton process has potential applications in the treatment of industrial wastewater containing phenol and related aromatic pollutants.

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.

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.

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.

Enhanced organic pollutants degradation and electricity production simultaneously via strengthening the radicals reaction in a novel Fenton-photocatalytic fuel cell system.

PubMed

Zhao, Kai; Zeng, Qingyi; Bai, Jing; Li, Jinhua; Xia, Ligang; Chen, Shuai; Zhou, Baoxue

2017-01-01

An enhanced result in organic pollutants degradation and simultaneous electricity production has been achieved by establishing a novel Fenton-photocatalytic fuel cell (Fenton-PFC) system in which TiO 2 nanotube arrays (TNA) was designed as a photoanode and ferrous ions were added. The proposed Fenton-PFC system can expand the radical reaction for organic pollutants degradation from the surface of electrodes to the whole solution system due to a continuous photoelectric Fenton reaction without continually adding any external voltage and ferrous ions. The cyclic reactions between ferrous ions (Fe 2+ /Fe 3+ ) and radicals and related species (HO, HO 2 , O 2 - and H 2 O 2 etc.) can be achieved at electrodes surface via a self-bias voltage yielded by the PFC. More importantly, the proposed Fenton-PFC system has hardly any sludge due to an effective radical reaction using a small amount of ferrous ions. The degradation rate of refractory organics, such as methyl orange, methylene blue, congo red and tetracycline, increased from 34.99%, 43.75%, 40.58% and 34.40% (the traditional PFC without Fe 2+ ) to 97.34%, 95.36%, 93.23% and 73.80% (the Fenton-PFC within Fe 2+ ) respectively after 60 min operation. Meanwhile, the electricity generation is up to 1.21-2.04 times larger than the traditional PFC. The proposed Fenton-PFC system provides a more economical and efficient way for energy recovery and wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study of the intensification of solar photo-Fenton degradation of carbamazepine with ferrioxalate complexes and ultrasound.

PubMed

Expósito, A J; Monteagudo, J M; Durán, A; San Martín, I; González, L

2018-01-15

The intensification of the solar photo-Fenton system with ferrioxalate photoactive complexes and ultrasound applied to the mineralization of 15mg/L carbamazepine aqueous solution (CBZ) was evaluated. The experiments were carried out in a solar compound parabolic collector (CPC) pilot plant reactor coupled to an ultrasonic processor. The dynamic behavior of hydroxyl radicals generated under the different studied reaction systems was discussed. The initial concentrations of hydrogen peroxide and ferrous/oxalic acid and pH were found to be the most significant variables (32.79%, 25.98% and 26.04%, respectively). Under the selected optimal conditions ([H 2 O 2 ] 0 =150mg/L; [Fe 2+ ] 0 =2.5mg/L/[(COOH) 2 ] 0 =12.1mg/L; pH=5) CBZ was fully degraded after 5min and 80% of TOC was removed using a solar photo-Fenton system intensified with ferrioxalate (SPFF). However, no improvement in the mineralization using SPFF process combined with ultrasound was observed. More mild pH conditions could be used in the SPFF system if compared to the traditional photo-Fenton (pH 3) acidic systems. Finally, a possible reaction pathway for the mineralization of CBZ by the SPFF system was proposed and therein discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Removal of trace metals and improvement of dredged sediment dewaterability by bioleaching combined with Fenton-like reaction.

PubMed

Zeng, Xiangfeng; Twardowska, Irena; Wei, Shuhe; Sun, Lina; Wang, Jun; Zhu, Jianyu; Cai, Jianchao

2015-05-15

Bioleaching by Aspergillus niger strain SY1 combined with Fenton-like reaction was optimized to improve trace metal removal and dewaterability of dredged sediments. The major optimized parameters were the duration of bioleaching and H₂O₂ dose in Fenton-like process (5 days and 2g H₂O₂/L, respectively). Bioleaching resulted in the removal of ≈90% of Cd, ≈60% of Zn and Cu, ≈20% of Pb, and in decrease of sediment pH from 6.6 to 2.5 due to organic acids produced by A. niger. After addition of H₂O₂, Fenton-like reaction was initiated and further metal removal occurred. Overall efficiency of the combined process comprised: (i) reduction of Cd content in sediment by 99.5%, Cu and Zn by >70% and Pb by 39% as a result of metal release bound in all mobilizable fractions; (ii) decrease of sediment capillary suction time (CST) from 98.2s to 10.1s (by 89.8%) and specific resistance to filtration (SRF) from 37.4×10(12)m/kg to 6.2×10(12)m/kg (by 83.8%), due to reducing amount of extracellular polymeric substances (EPS) by 68.7% and bound water content by 79.1%. The combined process was found to be an efficient method to remove trace metals and improve dewaterability of contaminated dredged sediments. Copyright © 2015 Elsevier B.V. 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.

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.

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.

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.

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.

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.

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.

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 ...

Effect of seven Indian plant extracts on Fenton reaction-mediated damage to DNA constituents.

PubMed

Kar, Indrani; Chattopadhyaya, Rajagopal

2017-11-01

The influences of substoichiometric amounts of seven plant extracts in the Fenton reaction-mediated damage to deoxynucleosides, deoxynucleoside monophosphates, deoxynucleoside triphosphates, and supercoiled plasmid DNA were studied to rationalize anticancer properties reported in some of these extracts. Extracts from Acacia catechu, Emblica officinalis, Spondias dulcis, Terminalia belerica, Terminalia chebula, as well as gallic acid, epicatechin, chebulagic acid and chebulinic acid enhance the extent of damage in Fenton reactions with all monomeric substrates but protect supercoiled plasmid DNA, compared to standard Fenton reactions. The damage to pyrimidine nucleosides/nucleotides is enhanced by these extracts and compounds to a greater extent than for purine ones in a concentration dependent manner. Dolichos biflorus and Hemidesmus indicus extracts generally do not show this enhancement for the monomeric substrates though they protect plasmid DNA. Compared to standard Fenton reactions for deoxynucleosides with ethanol, the presence of these five plant extracts render ethanol scavenging less effective as the radical is generated in the vicinity of the target. Since substoichiometric amounts of these extracts and the four compounds produce this effect, a catalytic mechanism involving the presence of a ternary complex of the nucleoside/nucleotide substrate, a plant compound and the hydroxyl radical is proposed. Such a mechanism cannot operate for plasmid DNA as the planar rings in the extract compounds cannot stack with the duplex DNA bases. These plant extracts, by enhancing Fenton reaction-mediated damage to deoxynucleoside triphosphates, slow down DNA replication in rapidly dividing cancer cells, thus contributing to their anticancer properties.

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.

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.

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.

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.

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.

Influence of dihydroxybenzenes on paracetamol and ciprofloxacin degradation and iron(III) reduction in Fenton processes.

PubMed

Costa E Silva, Beatriz; de Lima Perini, João Angelo; Nogueira, Raquel F Pupo

2017-03-01

The degradation of paracetamol (PCT) and ciprofloxacin (CIP) was compared in relation to the generation of dihydroxylated products, Fe(III) reduction and reaction rate in the presence of dihydroxybenzene (DHB) compounds, or under irradiation with free iron (Fe 3+ ) or citrate complex (Fecit) in Fenton or photo-Fenton process. The formation of hydroquinone (HQ) was observed only during PCT degradation in the dark, which increased drastically the rate of PCT degradation, since HQ formed was able to reduce Fe 3+ and contributed to PCT degradation efficiency. When HQ was initially added, PCT and CIP degradation rate in the dark was much higher in comparison to the absence of HQ, due to the higher and faster formation of Fe 2+ at the beginning of reaction. In the absence of HQ, no CIP degradation was observed; however, when HQ was added after 30 min, the degradation rate increased drastically. Ten PCT hydroxylated intermediates were identified in the absence of HQ, which could contribute for Fe(III) reduction and consequently to the degradation in a similar way as HQ. During CIP degradation, only one product of hydroxyl radical attack on benzene ring and substitution of the fluorine atom was identified when HQ was added to the reaction medium.

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.

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.

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-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.

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.

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.

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.

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.

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.

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.

VUV/UV light inducing accelerated phenol degradation with a low electric input† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6ra26043h Click here for additional data file.

PubMed Central

Li, Mengkai; Wen, Dong

2017-01-01

This study presents the first evidence for the accelerated degradation of phenol by Fenton's reagent in a mini-fluidic VUV/UV photoreaction system (MVPS). A low-pressure mercury lamp used in the MVPS led to a complete degradation of phenol within 4–6 min. The HO˙ and HO2˙ originating from both Fenton's reagent and VUV photolysis of water were identified with suitable radical scavengers. The effects of initial concentrations of phenol, H2O2 and Fe3+ as well as solution pH on phenol degradation kinetics were examined. Increasing the initial phenol concentration slowed down the phenol degradation, whereas increasing the initial H2O2 or Fe3+ concentration accelerated the phenol degradation. The optimal solution pH was 3.7. At both 254 and 185 nm, increasing phenol concentration enhanced its absorption for the incident photons. The reaction mechanism for the degradation of phenol was suggested consistent with the results obtained. This study indicates that the VUV/UV photo-Fenton process has potential applications in the treatment of industrial wastewater containing phenol and related aromatic pollutants. PMID:28496972

Photo-Fenton degradation of phenol, 2,4-dichlorophenoxyacetic acid and 2,4-dichlorophenol mixture in saline solution using a falling-film solar reactor.

PubMed

Luna, Airton J; Nascimento, Cláudio A O; Foletto, Edson Luiz; Moraes, José E F; Chiavone-Filhoe, Osvaldo

2014-01-01

In this work, a saline aqueous solution of phenol, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) was treated by the photo-Fenton process in a falling-film solar reactor. The influence of the parameters such as initial pH (5-7), initial concentration of Fe2+ (1-2.5mM) and rate of H202 addition (1.87-3.74mmol min-1) was investigated. The efficiency of photodegradation was determined from the removal of dissolved organic carbon (DOC), described by the species degradation of phenol, 2,4-D and 2,4-DCP. Response surface methodology was employed to assess the effects of the variables investigated, i.e. [Fe2+], [H202] and pH, in the photo-Fenton process with solar irradiation. The results reveal that the variables' initial concentration of Fe2+ and H202 presents predominant effect on pollutants' degradation in terms of DOC removal, while pH showed no influence. Under the most adequate experimental conditions, about 85% DOC removal was obtained in 180 min by using a reaction system employed here, and total removal of phenol, 2,4- and 2,4-DCP mixture in about 30min.

Degradation of Orange II by Fenton reaction using ilmenite as catalyst.

PubMed

Pataquiva-Mateus, A Y; Zea, H R; Ramirez, J H

2017-03-01

This work deals with the degradation of the azo-dye Orange II (OII) by a heterogeneous process with dark Fenton. Natural and purified ilmenites from Colombian soil were used as catalysts. The catalysts have different physicochemical properties and are basically composed of TiO 2 and Fe 2 O 3 . Ilmenites (FeTiO 3 ), raw materials highly available at low cost, were studied by means of conventional metallography (polished grain mounts), as well as BET, XRD, and XRF in order to determine their possible source area and the factors that influence their use as a catalyst for OII degradation. The pH, the ilmenite amount, the initial CH 2 O 2 , and the temperature of the reaction system were studied. Complete degradation of dye was observed within 7 h, while 90 % of OII was removed in 7 h using Cumaribo Ilmenite. Graphical Abstract ᅟ.

Degradation of aniline by heterogeneous Fenton's reaction using a Ni-Fe oxalate complex catalyst.

PubMed

Liu, Yucan; Zhang, Guangming; Fang, Shunyan; Chong, Shan; Zhu, Jia

2016-11-01

A Ni-Fe oxalate complex catalyst was synthesized and characterized by means of Brunauer-Emmet-Teller (BET) method, scanning electron microscope (SEM) and X-ray photo-electron spectroscopy (XPS). The catalyst showed good catalytic activity for aniline degradation by heterogeneous Fenton's reaction, in which the synergetic index was 9.3. The effects of reaction temperature, catalyst dosage, hydrogen peroxide concentration and initial pH were investigated. Under the optimum conditions (T = 293 K, catalyst dosage = 0.2 g/L, H2O2 concentration = 4 mmol/L and initial pH = 5.4), 100% aniline could be removed within 35 min, and approximately 88% deamination efficiency was achieved in 60 min. The aniline degradation process followed the pseudo-first-order kinetic (k = 0.177 min(-1)) with activation energy (Ea) of 49.4 kJ mol(-1). Aniline could be removed in a broad initial pH (3-8) due to the excellent pH-tolerance property of the catalyst. The detected ammonium ion indicated that deamination occurred during aniline degradation. It was proposed that deamination synchronized with aniline removal, and aniline was attacked by free radicals to generate benzoquinonimine and phenol. This system is promising for the removal of aniline from water. Copyright © 2016 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.

Using single-chamber microbial fuel cells as renewable power sources of electro-Fenton reactors for organic pollutant treatment.

PubMed

Zhu, Xiuping; Logan, Bruce E

2013-05-15

Electro-Fenton reactions can be very effective for organic pollutant degradation, but they typically require non-sustainable electrical power to produce hydrogen peroxide. Two-chamber microbial fuel cells (MFCs) have been proposed for pollutant treatment using Fenton-based reactions, but these types of MFCs have low power densities and require expensive membranes. Here, more efficient dual reactor systems were developed using a single-chamber MFC as a low-voltage power source to simultaneously accomplish H2O2 generation and Fe(2+) release for the Fenton reaction. In tests using phenol, 75 ± 2% of the total organic carbon (TOC) was removed in the electro-Fenton reactor in one cycle (22 h), and phenol was completely degraded to simple and readily biodegradable organic acids. Compared to previously developed systems based on two-chamber MFCs, the degradation efficiency of organic pollutants was substantially improved. These results demonstrate that this system is an energy-efficient and cost-effective approach for industrial wastewater treatment of certain pollutants. Copyright © 2013 Elsevier B.V. All rights reserved.

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.

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.

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.

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.

Strongly enhanced Fenton degradation of organic pollutants by cysteine: An aliphatic amino acid accelerator outweighs hydroquinone analogues.

PubMed

Li, Tuo; Zhao, Zhenwen; Wang, Quan; Xie, Pengfei; Ma, Jiahai

2016-11-15

Quinone-hydroquinone analogues have been proven to be efficient promoters of Fenton reactions by accelerating the Fe(III)/Fe(II) redox cycle along with self-destruction. However, so far there is little information on non-quinone-hydroquinone cocatalyst for Fenton reactions. This study found that cysteine, a common aliphatic amino acid, can strongly enhance Fenton degradation of organic pollutants by accelerating Fe(III)/Fe(II) redox cycle, as quinone-hydroquinone analogues do. Further, cysteine is superior to quinone-hydroquinone analogues in catalytic activity, H 2 O 2 utilization and atmospheric limits. The cocatalysis mechanism based on the cycle of cysteine/cystine was proposed. Copyright © 2016 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.

The role of Fenton reaction in ROS-induced toxicity underlying atherosclerosis - modeled and analyzed using a Petri net-based approach.

PubMed

Formanowicz, Dorota; Radom, Marcin; Rybarczyk, Agnieszka; Formanowicz, Piotr

2018-03-01

The superoxide-driven Fenton reaction plays an important role in the transformation of poorly reactive radicals into highly reactive ones. These highly reactive species (ROS), especially hydroxyl radicals can lead to many disturbances contributing to the endothelial dysfunction being a starting point for atherosclerosis. Although, iron has been identified as a possible culprit influencing formation of ROS, its significance in this process is still debatable. To better understand this phenomenon, the influence of blockade of Fenton reaction in a proposed Petri net-based model of the selected aspects of the iron ROS-induced toxicity in atherosclerosis has been evaluated. As a result of the blockade of iron ions formation in the model, even up to 70% of the paths leading to the progression of atherosclerosis in this model has been blocked. In addition, after adding to the model, the blockade of the lipids peroxidation paths, progression of atherosclerotic plaque has been not observed. This allowed to conclude that the superoxide-driven Fenton reaction plays a significant role in the atherosclerosis. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

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.

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.

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.

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.

Treatment of combined acid mine drainage (AMD)--flotation circuit effluents from copper mine via Fenton's process.

PubMed

Mahiroglu, Ayse; Tarlan-Yel, Esra; Sevimli, Mehmet Faik

2009-07-30

The treatability of a copper mine wastewater, including heavy metals, AMD, as well as flotation chemicals, with Fenton process was investigated. Fenton process seems advantageous for this treatment, because of Fe(2+) content and low pH of AMD. First, optimum Fe(2+) condition under constant H(2)O(2) was determined, and initial Fe(2+) content of AMD was found sufficient (120 mg/L for removal of chemical oxygen demand (COD) of 6125 mg/L). In the second step, without any additional Fe(2+), optimum H(2)O(2) dosage was determined as 40 mg/L. Fe(2+)/H(2)O(2) molar ratio of 1.8 was enough to achieve the best treatment performance. In all trials, initial pH of AMD was 4.8 and pH adjustment was not performed. Utilization of existing pH and Fe(2+), low H(2)O(2) requirements, and up to 98% treatment performances in COD, turbidity, color, Cu(2+), Zn(2+) made the proposed treatment system promising. Since the reaction occurs stepwise, a two-step kinetic model was applied and calculated theoretical maximum removal rate was consistent to experimental one, which validates the applied model. For the optimum molar ratio (1.8), 140 mL/L sludge of high density (1.094 g/mL), high settling velocity (0.16 cm/s) with low specific resistance (3.15 x 10(8)m/kg) was obtained. High reaction rates and easily dewaterable sludge characteristics also made the proposed method advantageous.

Optimization of the mineralization of a mixture of phenolic pollutants under a ferrioxalate-induced solar photo-Fenton process.

PubMed

Monteagudo, J M; Durán, A; Aguirre, M; San Martín, I

2011-01-15

The mineralization of solutions containing a mixture of three phenolic compounds, gallic, p-coumaric and protocatechuic acids, in a ferrioxalate-induced solar photo-Fenton process was investigated. The reactions were carried out in a pilot plant consisting of a compound parabolic collector (CPC) solar reactor. An optimization study was performed combining a multivariate experimental design and neuronal networks that included the following variables: pH, temperature, solar power, air flow and initial concentrations of H(2)O(2), Fe(II) and oxalic acid. Under optimal conditions, total elimination of the original compounds and 94% TOC removal of the mixture were achieved in 5 and 194 min, respectively. pH and initial concentrations of H(2)O(2) and Fe(II) were the most significant factors affecting the mixture mineralization. The molar correlation between consumed hydrogen peroxide and removed TOC was always between 1 and 3. A detailed analysis of the reaction was presented. The values of the pseudo-first-order mineralization kinetic rate constant, k(TOC), increased as initial Fe(II) and H(2)O(2) concentrations and temperature increased. The optimum pH value also slightly increased with greater Fe(II) and hydrogen peroxide concentrations but decreased when temperature increased. OH and O(2)(-) radicals were the main oxidative intermediate species in the process, although singlet oxygen ((1)O(2)) also played a role in the mineralization reaction. Copyright © 2010 Elsevier B.V. All rights reserved.

Treatment of hazardous waste landfill leachate using Fenton oxidation process

NASA Astrophysics Data System (ADS)

Singa, Pradeep Kumar; Hasnain Isa, Mohamed; Ho, Yeek-Chia; Lim, Jun-Wei

2018-03-01

The efficiency of Fenton's oxidation was assessed in this study for hazardous waste landfill leachate treatment. The two major reagents, which are generally employed in Fenton's process are H2O2 as oxidizing agent and Fe2+ as catalyst. Batch experiments were conducted to determine the effect of experimental conditions viz., reaction time, molar ratio, and Fenton reagent dosages, which are significant parameters that influence the degradation efficiencies of Fenton process were examined. It was found that under the favorable experimental conditions, maximum COD removal was 56.49%. The optimum experimental conditions were pH=3, H2O2/Fe2+ molar ratio = 3 and reaction time = 150 minutes. The optimal amount of hydrogen peroxide and iron were 0.12 mol/L and 0.04 mol/L respectively. High dosages of H2O2 and iron resulted in scavenging effects on OH• radicals and lowered degradation efficiency of organic compounds in the hazardous waste landfill leachate.

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

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.

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.

Improving dewaterability of waste activated sludge by combined conditioning with zero-valent iron and hydrogen peroxide.

PubMed

Zhou, Xu; Wang, Qilin; Jiang, Guangming; Zhang, Xiwang; Yuan, Zhiguo

2014-12-01

Improvement of sludge dewaterability is crucial for reducing the costs of sludge disposal in wastewater treatment plants. This study presents a novel method based on combined conditioning with zero-valent iron (ZVI) and hydrogen peroxide (HP) at pH 2.0 to improve dewaterability of a full-scale waste activated sludge (WAS). The combination of ZVI (0-750mg/L) and HP (0-750mg/L) at pH 2.0 substantially improved the WAS dewaterability due to Fenton-like reactions. The highest improvement in WAS dewaterability was attained at 500mg ZVI/L and 250mg HP/L, when the capillary suction time of the WAS was reduced by approximately 50%. Particle size distribution indicated that the sludge flocs were decomposed after conditioning. Economic analysis showed that combined conditioning with ZVI and HP was a more economically favorable method for improving WAS dewaterability than the classical Fenton reaction based method initiated by ferrous salts and HP. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application of a hybrid Electrocoagulation-Fenton process in yarn dye wastewater: Kinetic study

NASA Astrophysics Data System (ADS)

Riadi, L.; Sapei, L.; Lidiawati, T.; Agustin, Y. E.

2016-11-01

Reactive dyes contain a significant portion of colorants used in yarn dying process and also in textile industry. Since the COD content is usually high in such wastewater,we conducted a hybrid electrocoagulation-fenton method to treat the wastewater. This work describes the application of the hybrid system to the removal of chemical oxygen demand and color from the wastewater in a batch reactor. Having worked with initial pH of 3,0; temperature at 30°C, molar ratio of Fe2+/H2O2 =1/10 and the mol ratio H2O2/COD = 4, we got 88.3% COD conversion and 88.5% color removal. The COD degradation process can be explained in two phases, the first phase is instantaneous reaction and the second phase is first order reaction. The kinetic constant was 0.0053 minute-1 and the rate of COD degradation was 0.0053[COD] mg/L minute.

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

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.

Genotoxicity assessment of membrane concentrates of landfill leachate treated with Fenton reagent and UV-Fenton reagent using human hepatoma cell line.

PubMed

Wang, Guifang; Lu, Gang; Yin, Pinghe; Zhao, Ling; Yu, Qiming Jimmy

2016-04-15

Membrane concentrates of landfill leachates contain organic and inorganic contaminants that could be highly toxic and carcinogenic. In this paper, the genotoxicity of membrane concentrates before and after Fenton and UV-Fenton reagent was assessed. The cytotoxicity and genotoxicity was determined by using the methods of methyltetrazolium (MTT), cytokinesis-block micronucleus (CBMN) and comet assay in human hepatoma cells. MTT assay showed a cytotoxicity of 75% after 24h of exposure to the highest tested concentration of untreated concentrates, and no cytotoxocity for UV-Fenton and Fenton treated concentrates. Both CBMN and comet assays showed increased levels of genotoxicity in cells exposed to untreated concentrates, compared to those occurred in cells exposed to UV-Fenton and Fenton reagent treated concentrates. There was no significant difference between negative control and UV-Fenton treated concentrates for micronucleus and comet assay parameters. UV-Fenton and Fenton treatment, especially the former, were effective methods for degradation of bisphenol A and nonylphenol in concentrates. These findings showed UV-Fenton and Fenton reaction were effective methods for treatment of such complex concentrates, UV-Fenton reagent provided toxicological safety of the treated effluent, and the genotoxicity assays were found to be feasible tools for assessment of toxicity risks of complex concentrates. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Ceriporic acid B, an extracellular metabolite of Ceriporiopsis subvermispora, suppresses the depolymerization of cellulose by the Fenton reaction.

PubMed

Rahmawati, Noor; Ohashi, Yasunori; Watanabe, Takahito; Honda, Yoichi; Watanabe, Takashi

2005-01-01

The white rot fungus, Ceriporiopsis subvermispora, is able to degrade lignin in wood without intensive damage to cellulose. Since lignin biodegradation by white rot fungi proceeds by radical reactions, accompanied by the production of a large amount of Fe3+-reductant phenols and reductive radical species in the presence of iron ions, molecular oxygen, and H2O2, C. subvermispora has been proposed to possess a biological system which suppresses the production of a cellulolytic active oxygen species, *OH, by the Fenton reaction. In the present paper, we demonstrate that 1-nonadecene-2,3-dicarboxylic acid (ceriporic acid B), an extracellular metabolite of C. subvermispora, strongly inhibited *OH production and the depolymerization of cellulose by the Fenton reaction in the presence of iron ions, cellulose, H2O2, and a reductant for Fe3+, hydroquinone (HQ), at the physiological pH of the fungus.

Hydroxyl radical generation in electro-Fenton process with a gas-diffusion electrode: Linkages with electro-chemical generation of hydrogen peroxide and iron redox cycle.

PubMed

Yatagai, Tomonori; Ohkawa, Yoshiko; Kubo, Daichi; Kawase, Yoshinori

2017-01-02

The hydroxyl radical generation in an electro-Fenton process with a gas-diffusion electrode which is strongly linked with electro-chemical generation of hydrogen peroxide and iron redox cycle was studied. The OH radical generation subsequent to electro-chemical generations of H 2 O 2 was examined under the constant potential in the range of Fe 2+ dosage from 0 to 1.0 mM. The amount of generated OH radical initially increased and gradually decreased after the maximum was reached. The initial rate of OH radical generation increased for the Fe 2+ dosage <0.25 mM and at higher Fe 2+ dosages remained constant. At higher Fe 2+ dosages the precipitation of Fe might inhibit the enhancement of OH radical generation. The experiments for decolorization and total organic carbon (TOC) removal of azo-dye Orange II by the electro-Fenton process were conducted and the quick decolorization and slow TOC removal of Orange II were found. To quantify the linkages of OH radical generation with dynamic behaviors of electro-chemically generated H 2 O 2 and iron redox cycle and to investigate effects of OH radical generation on the decolorization and TOC removal of Orange II, novel reaction kinetic models were developed. The proposed models could satisfactory clarify the linkages of OH radical generation with electro-chemically generated H 2 O 2 and iron redox cycle and simulate the decolorization and TOC removal of Orange II by the electro-Fenton process.

Zn-Fe-CNTs catalytic in situ generation of H2O2 for Fenton-like degradation of sulfamethoxazole.

PubMed

Liu, Yong; Fan, Qin; Wang, Jianlong

2018-01-15

A novel Fenton-like catalyst (Zn-Fe-CNTs) capable of converting O 2 to H 2 O 2 and further to OH was prepared through infiltration fusion method followed by chemical replacement in argon atmosphere. The catalyst was characterized by SEM, EDS, TEM, XRD and XPS. The reaction between Zn-Fe-CNTs and O 2 in aqueous solution could generate H 2 O 2 in situ, which was further transferred to OH. The Fenton-like degradation of sulfamethoxazole (SMX) using Zn-Fe-CNTs as catalyst was evaluated. The results indicated that Zn-Fe-CNTs had a coral porous structure with a BET area of 51.67m 2 /g, exhibiting excellent adsorption capacity for SMX, which enhanced its degradation. The particles of Zn 0 and Fe 0 /Fe 2 O 3 were observed on the surface of Zn-Fe-CNTs. The mixture of Zn 0 and CNTs could reduce O 2 into H 2 O 2 by micro-electrolysis and Fe 0 /Fe 2 O 3 could catalyze in-situ generation of H 2 O 2 to produce OH through Fenton-like process. When initial pH=1.5, T=25°C, O 2 flow rate=400mL/min, Zn-Fe-CNTs=0.6g/L, SMX=25mg/L and reaction time=10min, the removal efficiency of SMX and TOC was 100% and 51.3%, respectively. The intermediates were detected and the possible pathway of SMX degradation and the mechanism of Zn-Fe-CNTs/O 2 process were tentatively proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

TiO2 photocatalysis causes DNA damage via fenton reaction-generated hydroxyl radicals during the recovery period.

PubMed

Gogniat, Gaëtan; Dukan, Sam

2007-12-01

Here, we show that resistance of Escherichia coli to TiO2 photocatalysis involves defenses against reactive oxygen species. Results support the idea that TiO2 photocatalysis generates damage which later becomes deleterious during recovery. We found this to be partly due to DNA attack via hydroxyl radicals generated by the Fenton reaction during recovery.

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.

Optimizing photo-Fenton like process for the removal of diesel fuel from the aqueous phase

PubMed Central

2014-01-01

Background In recent years, pollution of soil and groundwater caused by fuel leakage from old underground storage tanks, oil extraction process, refineries, fuel distribution terminals, improper disposal and also spills during transferring has been reported. Diesel fuel has created many problems for water resources. The main objectives of this research were focused on assessing the feasibility of using photo-Fenton like method using nano zero-valent iron (nZVI/UV/H2O2) in removing total petroleum hydrocarbons (TPH) and determining the optimal conditions using Taguchi method. Results The influence of different parameters including the initial concentration of TPH (0.1-1 mg/L), H2O2 concentration (5-20 mmole/L), nZVI concentration (10-100 mg/L), pH (3-9), and reaction time (15-120 min) on TPH reduction rate in diesel fuel were investigated. The variance analysis suggests that the optimal conditions for TPH reduction rate from diesel fuel in the aqueous phase are as follows: the initial TPH concentration equals to 0.7 mg/L, nZVI concentration 20 mg/L, H2O2 concentration equals to 5 mmol/L, pH 3, and the reaction time of 60 min and degree of significance for the study parameters are 7.643, 9.33, 13.318, 15.185 and 6.588%, respectively. The predicted removal rate in the optimal conditions was 95.8% and confirmed by data obtained in this study which was between 95-100%. Conclusion In conclusion, photo-Fenton like process using nZVI process may enhance the rate of diesel degradation in polluted water and could be used as a pretreatment step for the biological removal of TPH from diesel fuel in the aqueous phase. PMID:24955242

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.

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.

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.

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.

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.

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.

Effect of H(2)SO(4) and HCl in the anode purging solution for the electrokinetic-Fenton remediation of soil contaminated with phenanthrene.

PubMed

Kim, Jung-Hwan; Kim, Jong Yun; Kim, Soo-Sam

2009-09-01

The Electrokinetic-Fenton (EK-Fenton) process is a powerful technology to remediate organic-contaminated soil. The behavior of salts and acids introduced for the pH control has significant influence on the H(2)O(2) stabilization and destruction of organic contaminants. In this study, the effects of the type and concentration of acids, which were introduced at the anode, were investigated for the treatment of clayey soil contaminated with phenanthrene. In experiments with H(2)SO(4) as the anode solution, H(2)O(2) concentration in the anode reservoir decreased due to reaction between reduced species of sulfate and H(2)O(2), as time elapsed. By contrast, HCl as an electrolyte in the anode reservoir did not decrease the H(2)O(2) concentration in the anode reservoir. The reaction between the reduced species of sulfate and H(2)O(2) hindered the stabilization of H(2)O(2) in the soil and anode reservoir. In experiments with HCl for pH control, Cl(.), and Cl(2)(. -), which could be generated with mineral catalyzed Fenton-like reaction, did not significantly hinder H(2)O(2) stabilization. H(2)O(2) transportation with electro-osmotic flow and mineral catalyzed Fenton-like reaction on the soil surface resulted in the simultaneous transport and degradation of phenanthrene, which are dependent of the advancement rate of the acid front and electro-osmotic flow toward the cathode according to HCl and H(2)SO(4) concentrations in the anode purging solution.

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.

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.

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.

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.

Removal of phosphonates from industrial wastewater with UV/FeII, Fenton and UV/Fenton treatment.

PubMed

Rott, Eduard; Minke, Ralf; Bali, Ulusoy; Steinmetz, Heidrun

2017-10-01

Phosphonates are an important group of phosphorus-containing compounds due to their increasing industrial use and possible eutrophication potential. This study involves investigations into the methods UV/Fe II , Fenton and UV/Fenton for their removal from a pure water matrix and industrial wastewaters. It could be shown that the degradability of phosphonates by UV/Fe II (6 kWh/m 3 ) in pure water crucially depended on the pH and was higher the less phosphonate groups a phosphonate contains. The UV/Fe II method is recommended in particular for the treatment of concentrates with nitrogen-free phosphonates, only little turbidity and a low content of organic compounds. Using Fenton reagent, the degradation of polyphosphonates was relatively weak in a pure water matrix (<20% transformation to o-PO 4 3- ). By means of the Photo-Fenton method (6 kWh/m 3 ), those phosphonates with the smallest numbers of phosphonate groups were easier degraded as well at pH 3.5 in a pure water matrix (o-PO 4 3- formation rates of up to 80%). Despite an incomplete transformation of organically bound phosphorus to o-PO 4 3- with Fenton reagent in an organically highly polluted wastewater (max. 15%), an almost total removal of the total P occurred. The most efficient total P elimination rates were achieved in accordance with the following Fenton implementation: reaction → sludge separation (acidic) → neutralization of the supernatant → sludge separation (neutral). Accordingly, a neutralization directly after the reaction phase led to a lower total P removal extent. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Heterogeneous photo-Fenton decolorization of Orange II over Al-pillared Fe-smectite: response surface approach, degradation pathway, and toxicity evaluation.

PubMed

Li, Huiyuan; Li, Yanli; Xiang, Luojing; Huang, Qianqian; Qiu, Juanjuan; Zhang, Hui; Sivaiah, Matte Venkata; Baron, Fabien; Barrault, Joel; Petit, Sabine; Valange, Sabine

2015-04-28

A ferric smectite clay material was synthesized and further intercalated with Al2O3 pillars for the first time with the aim of evaluating its ability to be used as heterogeneous catalyst for the photo-Fenton decolorization of azo dye Orange II. UV irradiation was found to enhance the activity of the catalyst in the heterogeneous photo-Fenton process. Catalyst loading of 0.5g/L and hydrogen peroxide concentration of 13.5mM yielded a remarkable color removal, accompanied by excellent catalyst stability. The decolorization of Orange II followed the pseudo-first-order kinetics for initial dye concentrations from 20 to 160mg/L. The central composite design (CCD) based on the response surface methodology (RSM) was applied to evaluate the effects of several operating parameters, namely initial pH, catalyst loading and hydrogen peroxide concentration, on the decolorization efficiency. The RSM model was derived and the response surface plots were developed based on the results. Moreover, the main intermediate products were separated and identified using gas chromatography-mass spectrometry (GC-MS) and a possible degradation pathway was proposed accordingly. The acute toxicity experiments illustrated that the Daphniamagna immobilization rate continuously decreased during 150min reaction, indicating that the effluent was suitable for sequential biological treatment. Copyright © 2015 Elsevier B.V. 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.

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 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.

Influence of ultrasound on the heterogeneous Fenton-like oxidation of acetic acid.

PubMed

Cihanoğlu, Aydın; Gündüz, Gönül; Dükkancı, Meral

2017-11-01

The main objective of this study is to investigate the effect of ultrasound on the heterogeneous Fenton-like oxidation of acetic acid, which is one of the most resistant carboxylic acids to oxidation. For this purpose, firstly, the degradation of acetic acid was examined by using ultrasound alone and the effects of different parameters such as: type of sonication system, ultrasonic power, and addition of H 2 O 2 were investigated on the degradation of acetic acid. There was no chemical oxygen demand (COD) reduction in the presence of sonication alone. In the presence of the heterogeneous Fenton-like oxidation process alone, at 303 K, COD reduction reached only 7.1% after 2 h of reaction. However, the combination of the heterogeneous Fenton-like oxidation process with ultrasound increased the COD reduction from 7.1% to 25.5% after 2 h of reaction in an ultrasonic bath operated at 40 kHz, while the COD reduction only increased from 7.1% to 8.9% in the ultrasonic reactor operated at 850 kHz. This result indicates that the hybrid process of ultrasound and heterogeneous Fenton-like oxidation is a promising process to degrade acetic acid.

Using Central Composite Experimental Design to Optimize the Degradation of Tylosin from Aqueous Solution by Photo-Fenton Reaction

PubMed Central

Sarrai, Abd Elaziz; Hanini, Salah; Merzouk, Nachida Kasbadji; Tassalit, Djilali; Szabó, Tibor; Hernádi, Klára; Nagy, László

2016-01-01

The feasibility of the application of the Photo-Fenton process in the treatment of aqueous solution contaminated by Tylosin antibiotic was evaluated. The Response Surface Methodology (RSM) based on Central Composite Design (CCD) was used to evaluate and optimize the effect of hydrogen peroxide, ferrous ion concentration and initial pH as independent variables on the total organic carbon (TOC) removal as the response function. The interaction effects and optimal parameters were obtained by using MODDE software. The significance of the independent variables and their interactions was tested by means of analysis of variance (ANOVA) with a 95% confidence level. Results show that the concentration of the ferrous ion and pH were the main parameters affecting TOC removal, while peroxide concentration had a slight effect on the reaction. The optimum operating conditions to achieve maximum TOC removal were determined. The model prediction for maximum TOC removal was compared to the experimental result at optimal operating conditions. A good agreement between the model prediction and experimental results confirms the soundness of the developed model. PMID:28773551

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...

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

Chelate-Modified Fenton Reaction for the Degradation of Trichloroethylene in Aqueous and Two-Phase Systems

PubMed Central

Lewis, Scott; Lynch, Andrew; Bachas, Leonidas; Hampson, Steve; Ormsbee, Lindell; Bhattacharyya, Dibakar

2009-01-01

Abstract The primary objective of this research was to model and understand the chelate-modified Fenton reaction for the destruction of trichloroethylene (TCE) present in both the aqueous and organic (in the form of droplets) phases. The addition of a nontoxic chelate (L), such as citrate or gluconic acid, allows for operation at near-neutral pH and controlled release of Fe(II)/Fe(III). For the standard Fenton reaction at low pH in two-phase systems, an optimum H2O2:Fe(II) molar ratio was found to be between 1:1 and 2:1. Experimentation proved the chelate-modified Fenton reaction effectively dechlorinated TCE in both the aqueous and organic phases at pH 6–7 using low H2O2:Fe(II) molar ratios (4:1 to 8:1). Increasing the L:Fe ratio was found to decrease the rate of H2O2 degradation in both Fe(II) and Fe(III) systems at near-neutral pH. Generalized models were developed to predict the concentration of TCE in the aqueous phase and TCE droplet radius as a function of time using literature-reported hydroxyl radical reaction kinetics and mass transfer relationships. Additional aspects of this work include the reusability of the Fe–citrate complex under repeated H2O2 injections in real water systems as well as packed column studies for simulated groundwater injection. PMID:20418966

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.

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.

Application of solar photo-Fenton toward toxicity removal and textile wastewater reuse.

PubMed

Starling, Maria Clara V M; Dos Santos, Paulo Henrique Rodrigues; de Souza, Felipe Antônio Ribeiro; Oliveira, Sílvia Corrêa; Leão, Mônica M D; Amorim, Camila C

2017-05-01

Solar photo-Fenton represents an innovative and low-cost option for the treatment of recalcitrant industrial wastewater, such as the textile wastewater. Textile wastewater usually shows high acute toxic and variability and may be composed of many different chemical compounds. This study aimed at optimizing and validating solar photo-Fenton treatment of textile wastewater in a semi-pilot compound parabolic collector (CPC) for toxicity removal and wastewater reclamation. In addition, treated wastewater reuse feasibility was investigated through pilot tests. Experimental design performed in this study indicated optimum condition for solar photo-Fenton reaction (20 mg L -1 of Fe 2+ and 500 mg L -1 of H 2 O 2 ; pH 2.8), which achieved 96 % removal of dissolved organic carbon (DOC) and 99 % absorbance removal. A toxicity peak was detected during treatment, suggesting that highly toxic transformation products were formed during reaction. Toxic intermediates were properly removed during solar photo-Fenton (SPF) treatment along with the generation of oxalic acid as an ultimate product of degradation and COS increase. Different samples of real textile wastewater were treated in order to validate optimized treatment condition with regard to wastewater variability. Results showed median organic carbon removal near 90 %. Finally, reuse of treated textile wastewater in both dyeing and washing stages of production was successful. These results confirm that solar photo-Fenton, as a single treatment, enables wastewater reclamation in the textile industry. Graphical abstract Solar photo-Fenton as a revolutionary treatment technology for "closing-the-loop" in the textile industry.

Efficient degradation of sulfamethazine in simulated and real wastewater at slightly basic pH values using Co-SAM-SCS /H2O2 Fenton-like system.

PubMed

Cheng, Min; Zeng, Guangming; Huang, Danlian; Lai, Cui; Liu, Yang; Zhang, Chen; Wan, Jia; Hu, Liang; Zhou, Chengyun; Xiong, Weiping

2018-07-01

The presence of antibiotics in aquatic environments has attracted global concern. Fenton process is an attractive yet challenging method for antibiotics degradation, especially when such a reaction can be conducted at neutral pH values. In this study, a novel composite Fe/Co catalyst was synthesized via the modification of steel converter slag (SCS) by salicylic acid-methanol (SAM) and cobalt nitrate (Co(NO 3 ) 2 ). The catalysts were characterized by N 2 -Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results indicated that the Co-SAM-SCS/H 2 O 2 Fenton-like system was very effective for sulfamethazine (SMZ) degradation at a wide pH range. At initial pH of 7.0, the degradation rate of SMZ in Co-SAM-SCS/H 2 O 2 system was 2.48, 3.20, 6.18, and 16.21 times of that in Fe-SAM-SCS/H 2 O 2 , SAM-SCS/H 2 O 2 , Co(NO 3 ) 2 /H 2 O 2 and SCS/H 2 O 2 system, respectively. The preliminary analysis suggested that high surface area of Co-SAM-SCS sample and synergistic effect between introduced Co and SAM-SCS are responsible for the efficient catalytic activity. During the degradation, three main intermediates were identified by high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis. Based on this, a possible degradation pathway was proposed. The SEM images, XRD patterns and XPS spectra before and after the reactions demonstrate that the crystal and chemical structure of Co-SAM-SCS after five cycles are almost unchanged. Besides, the Co-SAM-SCS presented low iron and cobalt leaching (0.17 mg/L and 2.36 mg/L, respectively). The studied Fenton-like process also showed high degradation of SMZ in river water and municipal wastewater. The progress will bring valuable insights to develop high-performance heterogeneous Fenton-like catalysts for environmental remediation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Does the photo-Fenton reaction work for microalgae control? A case study with Desmodesmus subspicatus.

PubMed

Torres, Mariana de Almeida; de Liz, Marcus Vinicius; Martins, Lucia Regina Rocha; Freitas, Adriane Martins

2018-04-18

Increased concentrations of nutrients in water bodies caused by effluent discharge, fertilizers and other inputs can lead to artificial eutrophication, increasing the primary productivity, bringing well-known and serious consequences to the environment (such as excessive macrophyte and microalgae growth). Most strategies for phytoplankton control in aquatic ecosystems result in metal accumulation or toxic by-product formation after chlorination. Concerning this matter, the photo-Fenton process (usually applied in wastewater treatment and degradation of a variety of contaminants) has been studied for water and effluent disinfection. However, its application in microalgae inactivation has not been reported until now. Therefore, this work aimed to evaluate the process effectiveness in inactivating microalgae, using Desmodesmus subspicatus as a model. Photo-Fenton experiments were carried out at the lab scale, at 105 cells per mL with 20 mg L-1 of H2O2 and 5 mg L-1 of Fe2+ (complexed with oxalic acid). The cell concentration and Growth Inhibition Test (GIT) were used to evaluate the process efficiency and Scanning Electron Microscopy (SEM) to analyze any alterations in the cell morphology. After performing the photo-Fenton reaction, the individual contribution of the reactants and radiation was investigated. The cell concentration was not significantly reduced during the photo-Fenton reaction, but SEM images indicated possible morphology alterations and the GIT showed the loss of cell viability after 30 minutes of exposure. Effects on the cell growth were also observed when exposed only to hydrogen peroxide.

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

Heterogeneous UV/Fenton degradation of bisphenol A catalyzed by synergistic effects of FeCo2O4/TiO2/GO.

PubMed

Bai, Xue; Lyu, Lingling; Ma, Wenqiang; Ye, Zhengfang

2016-11-01

A new method for bisphenol A (BPA) degradation in aqueous solution was developed. The characteristics of BPA degradation in a heterogeneous ultraviolet (UV)/Fenton reaction catalyzed by FeCo 2 O 4 /TiO 2 /graphite oxide (GO) were studied. The properties of the synthesized catalysts were characterized using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry. FeCo 2 O 4 and TiO 2 were grown as spherical shape, rough surface, and relatively uniform on the surface of GO (FeCo 2 O 4 /TiO 2 /GO). Batch tests were conducted to evaluate the effects of the initial pH, FeCo 2 O 4 /TiO 2 /GO dosage, and H 2 O 2 concentration on BPA degradation. In a system with 0.5 g L -1 of FeCo 2 O 4 /TiO 2 /GO and 10 mmol L -1 of H 2 O 2 , approximately 90 % of BPA (20 mg L -1 ) was degraded within 240 min of UV irradiation at pH 6.0. The reused FeCo 2 O 4 /TiO 2 /GO catalyst retained its activity after three cycles, which indicates that it is stable and reusable. The heterogeneous UV/Fenton reaction catalyzed by FeCo 2 O 4 /TiO 2 /GO is a promising advanced oxidation technology for treating wastewater that contains BPA.

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...

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...

ROLE OF REDUCTANTS IN THE ENHANCED DESORPTION AND TRANSFORMATION OF CHOROALIPHATIC COMPOUNDS BY MODIFIED FENTON'S REACTIONS. (R826163)

EPA Science Inventory

The mechanism for enhanced desorption of chloroaliphatic compounds from a
silty loam soil by modified Fenton's reagent was investigated using a series of
probe compounds of varying hydrophobicities. Hexachloroethane, which has
negligible reactivity with hydroxyl ra...

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.

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.

Oxidation of sulfamethoxazole by UVA radiation and modified Fenton reagent: toxicity and biodegradability of by-products.

PubMed

Marciocha, D; Kalka, J; Turek-Szytow, J; Wiszniowski, J; Surmacz-Górska, J

2009-01-01

Improvement of sulfamethoxazole (4-amino-N-(5-methylisoxazol-3-yl)-benzenesulfonamide-SMX) biodegradability using a modified Fenton's reaction has been studied. The modification consists of replacing hydrogen peroxide with atmospheric air and adding copper sulphate as a reaction promoter. Two series of experiments were carried out. The first (Series 1) was conducted using only the catalysts with aeration. In the second series (Series 2), cycles of UVA radiation and aeration were used. During UVA radiation, the removal of sulfamethoxazole proceeds less rapidly than in only aerated solution. After 1.5 h of these two processes, the SMX degradation was 23% in Series 2 and 59% in Series 1. The opposite trend was observed for mineralization and the removal of DOC was about 5% higher in Series 2 than in Series 1. The FTIR spectra of the extracts of reaction products yielded by four organic solvents of varying polarity revealed a wide diversity of functional groups in the post-reaction mixture in comparison to the extracts from sulfamethoxazole solution. Based on FTIR analysis, several oxidation products of sulfamethoxazole are proposed. Apparently, hydroxyl radicals initially attack sulphonamide bonds, resulting in the formation of sulfanilic acid and 3-amino-5-methylisoxazole. Irrespective of the reference organism used in toxicity tests, the post-reaction mixture in the Series 2 was more toxic than the post-reaction mixture in Series 1. In contrast, the biodegradability calculated as BOD(5)/DOC ratio, was higher for post-reaction mixture 2 and amounted to 0.43.

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.

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.

Electro-Fenton as a feasible advanced treatment process to produce reclaimed water.

PubMed

Durán Moreno, A; Frontana-Uribe, B A; Ramírez Zamora, R M

2004-01-01

The feasibility of the electro-Fenton process to generate simultaneously both of the Fenton's reagent species (Fe2+/H2O2), was assessed as a potentially more economical alternative to the classical Fenton's reaction to produce reclaimed water. An air-saturated combined wastewater (mixture of municipal and laboratory effluents) was treated in discontinuous and continuous reactors at pH = 3.5. The discontinuous reactor was a 2 L electrochemical laboratory cell fitted with concentric graphite and iron electrodes. The continuous reactor tests used a pilot treatment system comprising the aforementioned electrochemical cell, two clarifiers and one sand filter. Several tests were carried out at different conditions of reaction time (0-60 min) and electrical current values (0.2-1.0 A) in the discontinuous reactor. The best operating conditions were 60 min and 1 A without filtration of effluents. At these conditions, in discontinuous and continuous reactors with filtration, the COD, turbidity and color removal were 65-74.8%, 77-92.3% and 80-100%, respectively. Fecal and total coliforms, Escherichia coli, Shigella and Salmonella sp. were not detected at the end of the pilot treatment system. Electrogeneration of the Fenton's reagent is also economical; its cost is one-fifth the cost reported for Advanced Primary Treatment.

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.

Physico-chemical, microbiological and ecotoxicological evaluation of a septic tank/Fenton reaction combination for the treatment of hospital wastewaters.

PubMed

Berto, Josiani; Rochenbach, Gisele Canan; Barreiros, Marco Antonio B; Corrêa, Albertina X R; Peluso-Silva, Sandra; Radetski, Claudemir Marcos

2009-05-01

Hospital wastewater is considered a complex mixture populated with pathogenic microorganisms. The genetic constitution of these microorganisms can be changed through the direct and indirect effects of hospital wastewater constituents, leading to the appearance of antibiotic multi-resistant bacteria. To avoid environmental contamination hospital wastewaters must be treated. The objective of this study was to evaluate the efficiency of hospital wastewater treated by a combined process of biological degradation (septic tank) and the Fenton reaction. Thus, after septic tank biodegradation, batch Fenton reaction experiments were performed in a laboratory-scale reactor and the effectiveness of this sequential treatment was evaluated by a physico-chemical/microbiological time-course analysis of COD, BOD(5), and thermotolerant and total coliforms. The results showed that after 120min of Fenton treatment BOD(5) and COD values decreased by 90.6% and 91.0%, respectively. The BOD(5)/COD ratio changed from 0.46 to 0.48 after 120min of treatment. Bacterial removal efficiency reached 100%, while biotests carried out with Scenedesmus subspicatus and Daphnia magna showed a significant decrease in the ecotoxicity of hospital wastewater after the sequential treatment. The use of this combined system would ensure that neither multi-resistant bacteria nor ecotoxic substances are released to the environment through hospital wastewater discharge.

Direct conversion from Jerusalem artichoke to hydroxymethylfurfural (HMF) using the Fenton reaction.

PubMed

Seo, Yeong Hwan; Han, Jong-In

2014-05-15

A simple method for hydroxymethylfurfural (HMF) production from non-crop biomass of the Jerusalem artichoke was developed using the Fenton reaction, in a mixture of 2-butanol and water. Four parameters (temperature, reaction time, Fe(2+) concentration, and H2O2 concentration) were identified as experimental factors, and HMF yield was selected as the response parameter. The experimental factors were optimised by employing Response Surface Methodology (RSM). The maximum HMF yield, of 46%, was obtained with a reaction time of 90 min, Fe(2+) concentration of 1.3 mM, and 0.47 M of H2O2 at 180 °C. Copyright © 2014. Published by Elsevier Ltd.

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.

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.

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.

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.

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.

Photonic efficiency of the photodegradation of paracetamol in water by the photo-Fenton process.

PubMed

Yamal-Turbay, E; Ortega, E; Conte, L O; Graells, M; Mansilla, H D; Alfano, O M; Pérez-Moya, M

2015-01-01

An experimental study of the homogeneous Fenton and photo-Fenton degradation of 4-amidophenol (paracetamol, PCT) is presented. For all the operation conditions evaluated, PCT degradation is efficiently attained by both Fenton and photo-Fenton processes. Also, photonic efficiencies of PCT degradation and mineralization are determined under different experimental conditions, characterizing the influence of hydrogen peroxide (H2O2) and Fe(II) on both contaminant degradation and sample mineralization. The maximum photonic degradation efficiencies for 5 and 10 mg L(-1) Fe(II) were 3.9 (H2O2 = 189 mg L(-1)) and 5 (H2O2 = 378 mg L(-1)), respectively. For higher concentrations of oxidant, H2O2 acts as a "scavenger" radical, competing in pollutant degradation and reducing the reaction rate. Moreover, in order to quantify the consumption of the oxidizing agent, the specific consumption of the hydrogen peroxide was also evaluated. For all operating conditions of both hydrogen peroxide and Fe(II) concentration, the consumption values obtained for Fenton process were always higher than the corresponding values observed for photo-Fenton. This implies a less efficient use of the oxidizing agent for dark conditions.

Comparative study of the degradation of carbamazepine in water by advanced oxidation processes.

PubMed

Dai, Chao-Meng; Zhou, Xue-Fei; Zhang, Ya-Lei; Duan, Yan-Ping; Qiang, Zhi-Min; Zhang, Tian C

2012-06-01

Degradation of carbamazepine (CBZ) using ultraviolet (UV), UV/H2O2, Fenton, UV/Fenton and photocatalytic oxidation with TiO2 (UV/TiO2) was studied in deionized water. The five different oxidation processes were compared for the removal kinetics of CBZ. The results showed that all the processes followed pseudo-first-order kinetics. The direct photolysis (UV alone) was found to be less effective than UV/H2O2 oxidation for the degradation of CBZ. An approximate 20% increase in the CBZ removal efficiency occurred with the UV/Fenton reaction as compared with the Fenton oxidation. In the UV/TiO2 system, the kinetics of CBZ degradation in the presence of different concentrations of TiO2 followed the pseudo-first order degradation, which was consistent with the Langmuir-Hinshelwood (L-H) model. On a time basis, the degradation efficiencies ofCBZ were in the following order: UV/Fenton (86.9% +/- 1.7%) > UV/TiO2 (70.4% +/- 4.2%) > Fenton (67.8% +/- 2.6%) > UV/H2O2 (40.65 +/- 5.1%) > UV (12.2% +/- 1.4%). However, the lowest cost was obtained with the Fenton process.

Solar photo-degradation of a pharmaceutical wastewater effluent in a semi-industrial autonomous plant.

PubMed

Expósito, Antonio J; Durán, Antonio; Monteagudo, José M; Acevedo, Alba

2016-05-01

An industrial wastewater effluent coming from a pharmaceutical laboratory has been treated in a semi-industrial autonomous solar compound parabolic collector (CPC) plant. A photo-Fenton process assisted with ferrioxalate has been used. Up to 79% of TOC can be removed in 2 h depending on initial conditions when treating an aqueous effluent containing up to 400 ppm of initial organic carbon concentration (TOC). An initial ratio of Fe(II)/TOC higher than 0.5 guarantees a high removal. It can be seen that most of TOC removal occurs early in the first hour of reaction. After this time, mineralization was very slow, although H2O2 was still present in solution. Indeed it decomposed to form oxygen in inefficient reactions. It is clear that remaining TOC was mainly due to the presence of acetates which are difficult to degrade. Copyright © 2016 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.

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.

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.

UVA-potentiated damage to calf thymus DNA by Fenton reaction system and protection by para-aminobenzoic acid.

PubMed

Shih, M K; Hu, M L

1996-03-01

Calf thymus DNA was irradiated with low-intensity UVA (main output at 365 nm, 2 mW cm-2 or 36 kJ m-2 for 30 min), and the role of metal ions, hydrogen peroxide and reactive oxygen species (ROS) was examined. DNA damage was measured as thiobarbituric acid-reactive substances (possibly from degradation of deoxyribose) and as changes in ethidium bromide-DNA fluorescence due to unwinding from strand breaks. Under the present experimental conditions, UVA alone or in the presence of H2O2 had no effect on DNA but slightly enhanced the damage by iron/EDTA. Ultraviolet A strongly enhanced DNA damage (ca four- to five-fold) by the Fenton reaction system (50 microM Fe2+/100 microM EDTA + 0.5 mM H2O2). The results suggest that the Fenton reaction system was "photosensitized" to damage DNA by low-intensity UVA radiation. The enhanced damage by UVA was attributed in part to the reduction of Fe3+ to Fe2+. Ultraviolet A had no effect when iron (ferric or ferrous) ions were replaced by Cu2+, Zn2+, Mn2+ or Cd2+. The ROS involved in the UVA-enhanced damage to DNA by the Fenton reagents were OH and, to a lesser extent, superoxide anions. The UVA-potentiated DNA damage by the Fenton reaction system was then used to examine the protective effect of para-aminobenzoate (PABA), a UVB-absorbing sunscreen that protects against photocarcinogenesis in hairless mice. The results show that PABA and mannitol dose-dependently inhibited the damage with concentrations required for 50% inhibition at 0.1 mM and 3 mM, respectively. The protection by PABA was attributed to its radical-scavenging ability because PABA does not absorb light in the UVA region. These findings may be relevant to the biological damage by UVA and suggest that PABA is useful in protection against photocarcinogenesis by wide-range UV radiation.

Degradation of thiamethoxam by the synergetic effect between anodic oxidation and Fenton reactions.

PubMed

Meijide, J; Gómez, J; Pazos, M; Sanromán, M A

2016-12-05

In this work, a comparative study using anodic oxidation, Fenton and electro-Fenton treatments was performed in order to determine the synergic effect for the removal of thiamethoxan. The results determined that electro-Fenton process showed high efficiency in comparison with Fenton or anodic oxidation. After that, this hybrid process was optimized and the influence of iron catalyst concentration and applied current intensity on the degradation and mineralization were evaluated. Degradation profiles were monitored by high performance liquid chromatography (HPLC) being satisfactorily described by pseudo-first order kinetic model. At the optimal experimental conditions (300mA and 0.2mM Fe(+2)), the complete degradation of thiamethoxam was achieved after 10min. On the other hand, mineralization of thiamethoxam was monitored by total organic carbon (TOC) decay reaching more than 92% of TOC removal after 8h. Furthermore, a plausible mineralization pathway for the thiamethoxam degradation was proposed based on the identification of by-products such as aromatic intermediates, carboxylic acids and inorganic ions released throughout electro-Fenton process. Copyright © 2016 Elsevier B.V. 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.

Fe3-xCuxO4 as highly active heterogeneous Fenton-like catalysts toward elemental mercury removal.

PubMed

Zhou, Changsong; Sun, Lushi; Zhang, Anchao; Wu, Xiaofeng; Ma, Chuan; Su, Sheng; Hu, Song; Xiang, Jun

2015-04-01

A series of novel spinel Fe3-xCuxO4 (0

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.

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.

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.

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.

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.

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.

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.

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.

Sono-photo-Fenton oxidation of bisphenol-A over a LaFeO3 perovskite catalyst.

PubMed

Dükkancı, Meral

2018-01-01

In this study, oxidation of bisphenol-A (IUPAC name - 2,2-(4,4-dihydroxyphenyl, BPA), which is an endocrine disrupting phenolic compound used in the polycarbonate plastic and epoxy resin industry, was investigated using sono-photo-Fenton process under visible light irradiation in the presence of an iron containing perovskite catalyst, LaFeO 3 . The catalyst prepared by sol-gel method, calcined at 500°C showed a catalytic activity in BPA oxidation using sono-photo-Fenton process with a degradation degree and a chemical oxygen demand (COD) reduction of 21.8% and 11.2%, respectively. Degradation of BPA was studied by using individual and combined advanced oxidation techniques including sonication, heterogeneous Fenton reaction and photo oxidation over this catalyst to understand the effect of each process on degradation of BPA. It was seen, the role of sonication was very important in hybrid sono-photo-Fenton process due to the pyrolysis and sonoluminescence effects caused by ultrasonic irradiation. The prepared LaFeO 3 perovskite catalyst was a good sonocatalyst rather than a photocatalyst. Sonication was not only the effective process to degrade BPA but also it was the cost effective process in terms of energy consumption. The studies show that the energy consumption is lower in the sono-Fenton process than those in the photo-Fenton and sono-photo- Fenton processes. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Enhancement of activated sludge disintegration and dewaterability by Fenton process

NASA Astrophysics Data System (ADS)

Heng, G. C.; Isa, M. H.

2016-06-01

Municipal and industrial wastewater treatment plants produce large amounts of sludge. This excess sludge is an inevitable drawback inherent to the activated sludge process. In this study, the waste activated sludge was obtained from the campus wastewater treatment plant at Universiti Teknologi PETRONAS (UTP), Malaysia. Fenton pretreatment was optimized by using the response surface methodology (RSM) to study the effects of three operating conditions including the dosage of H2O2 (g H2O2/kg TS), the molar ratio of H2O2/Fe2+ and reaction time. The optimum operating variables to achieve MLVSS removal 65%, CST reduction 28%, sCOD 11000 mg/L and EPS 500 mg/L were: 1000 g H2O2/kg TS, H2O2/Fe2+ molar ratio 70 and reaction time 45 min. Fenton process was proved to be able to enhance the sludge disintegration and dewaterability.

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.

In vitro screening of Fe2+-chelating effect by a Fenton's reaction-luminol chemiluminescence system.

PubMed

Wada, Mitsuhiro; Komatsu, Hiroaki; Ikeda, Rie; Aburjai, Talal A; Alkhalil, Suleiman M; Kuroda, Naotaka; Nakashima, Kenichiro

2014-11-01

In vitro screening of a Fe(2+) -chelating effect using a Fenton's reaction-luminol chemiluminescence (CL) system is described. The luminescence between the reactive oxygen species generated by the Fenton's reaction and luminol was decreased on capturing Fe(2+) using a chelator. The proposed method can prevent the consumption of expensive seed compounds (drug discovery candidates) owing to the high sensitivity of CL detection. Therefore, the assay could be performed using small volumes of sample solution (150 μL) at micromolar concentrations. After optimization of the screening conditions, the efficacies of conventional chelators such as ethylenediaminetetraacetic acid (EDTA), diethylentriaminepentaacetic acid (DETAPAC), deferoxamine, deferiprone and 1,10-phenanthroline were examined. EC50 values for these compounds (except 1,10-phenanthroline) were in the range 3.20 ± 0.87 to 9.57 ± 0.64 μM (n = 3). Rapid measurement of the Fe(2+)-chelating effect with an assay run time of a few minutes could be achieved using the proposed method. In addition, the specificity of the method was discussed. Copyright © 2014 John Wiley & Sons, Ltd.

Optimisation of electro-Fenton denitrification of a model wastewater using a response surface methodology.

PubMed

Virkutyte, Jurate; Rokhina, Ekaterina; Jegatheesan, Veeriah

2010-03-01

Electro-Fenton denitrification of a model wastewater was studied using platinized titanium electrodes in a batch electrochemical reactor. The model wastewater was prepared from components based on the real aquaculture effluent with nitrate concentrations varying from 200 to 800 mg L(-1). The technical as well as scientific feasibility of the method was assessed by the relationship between the most significant process variables such as various Fenton's reagent to hydrogen peroxide ratios (1:5; 1:20 and 1:50) and current densities (0.17 mA cm(-2), 0.34 mA cm(-2) and 0.69 mA cm(-2)) and their response on denitrification efficiency in terms of nitrate degradation using central composite Box-Behnken experimental design was determined. The goodness of the model was checked by the coefficient of determination R(2) (0.9775), the corresponding analysis of variance P>F and a parity plot. The ANOVA results indicated that the proposed model was significant and therefore can be used to optimize denitrification of a model wastewater. The optimum reaction conditions were found to be 1:20 Fenton's reagent/hydrogen peroxide ratio, 400 mg L(-1) initial nitrate concentration and 0.34 mA cm(-2) current density. Treatment costs in terms of electricity expenditure at 0.17, 0.34 and 0.69 mA cm(-2) was 7.6, 16 and 41.8 euro, respectively, per kilogram of nitrates and 1, 2 and 4 euro, respectively, per cubic meter of wastewater. 2009 Elsevier Ltd. All rights reserved.

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.

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

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.

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.

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.

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.

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).

Treatment of oilfield wastewater by combined process of micro-electrolysis, Fenton oxidation and coagulation.

PubMed

Zhang, Zhenchao

2017-12-01

In this study, a combined process was developed that included micro-electrolysis, Fenton oxidation and coagulation to treat oilfield fracturing wastewater. Micro-electrolysis and Fenton oxidation were applied to reduce chemical oxygen demand (COD) organic load and to enhance organic components gradability, respectively. Orthogonal experiment were employed to investigate the influence factors of micro-electrolysis and Fenton oxidation on COD removal efficiency. For micro-electrolysis, the optimum conditions were: pH, 3; iron-carbon dosage, 50 mg/L; mass ratio of iron-carbon, 2:3; reaction time, 60 min. For Fenton oxidation, a total reaction time of 90 min, a H 2 O 2 dosage of 12 mg/L, with a H 2 O 2 /Fe 2+ mole ratio of 30, pH of 3 were selected to achieve optimum oxidation. The optimum conditions in coagulation process: pH, cationic polyacrylamide dosage, mixing speed and time is 4.3, 2 mg/L, 150 rpm and 30 s, respectively. In the continuous treatment process under optimized conditions, the COD of oily wastewater fell 56.95%, 46.23%, 30.67%, respectively, from last stage and the total COD removal efficiency reached 83.94% (from 4,314 to 693 mg/L). In the overall treatment process under optimized conditions, the COD of oily wastewater was reduced from 4,314 to 637 mg/L, and the COD removal efficiency reached 85.23%. The contribution of each stage is 68.45% (micro-electrolysis), 24.07% (Fenton oxidation), 7.48% (coagulation), respectively. Micro-electrolysis is the uppermost influencing process on COD removal. Compared with the COD removal efficiency of three processes on raw wastewater under optimized conditions: the COD removal efficiency of single micro-electrolysis, single Fenton oxidation, single coagulation is 58.34%, 44.88% and 39.72%, respectively. Experiments proved the effect of combined process is marvelous and the overall water quality of the final effluent could meet the class III national wastewater discharge standard of petrochemical industry of China (GB8978-1996).

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.

Fenton treatment of bio-treated fermentation-based pharmaceutical wastewater: removal and conversion of organic pollutants as well as estimation of operational costs.

PubMed

Cheng, Yunqin; Chen, Yunlu; Lu, Juncheng; Nie, Jianxin; Liu, Yan

2018-04-01

The Fenton process is used as a tertiary treatment to remove organic pollutants from the effluent of bio-treated pharmaceutical wastewater (EBPW). The optimal and most appropriate Fenton conditions were determined by an orthogonal array test and single-factor experiments. The removal of chemical oxygen demand (COD) was influenced by the following factors in a descending order: H 2 O 2 /Fe(II) molar ratio > H 2 O 2 dosage > reaction time. Under the most appropriate Fenton conditions (H 2 O 2 /Fe(II) molar ratio of 1:1, H 2 O 2 dosage of 120 mg L -1 and reaction time of 10 min), the COD and dissolved organic carbon (DOC) were removed with efficiencies of 62 and 53%, respectively, which met the national discharge standard (GB 21903-2008) for the Lake Tai Basin, China. However, the Fenton treatment was inadequate for removal of N compounds, and the removal of organic nitrogen led to an increment in N-NH 3 from 3.28 to 19.71 mg L -1 . Proteins and polysaccharides were completely removed, and humic acids (HAs) were partly removed with an efficiency of 55%. Three-dimensional excitation/emission matrix spectra (3DEEMs) indicated complete removal of fulvic acid-like substances and 90% reduction in the florescence intensity of humic acid-like substances. Organic pollutants with molecular weights (MW) > 10 kDa were completely removed, MW 5-10 kDa were degraded into smaller MW ones, and some low molecular weight acids (MW 0.1-1 kDa) were mineralized during the Fenton process. Some species, including pharmaceutical intermediates and solvents were detected by gas chromatography-mass spectrometry (GC-MS). The operational costs of the Fenton's treatment were estimated to be 0.58 yuan RMB/m 3 EBPW based on reagent usage and iron sludge treatment and disposal.

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.

IN-SITU REGENERATION OF GRANULAR ACTIVATED CARBON (GAC) USING FENTON'S REAGENTS

EPA Science Inventory

Fenton-dependent regeneration of granular activated carbon (GAC) initially saturated with one of several chlorinated aliphatic contaminants was studied in batch and continuous-flow reactors. Homogeneous and heterogeneous experiments were designed to investigate the effects of va...

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.

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.

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.

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.

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.

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.

Efficient Destruction of Pollutants in Water by a Dual-Reaction-Center Fenton-like Process over Carbon Nitride Compounds-Complexed Cu(II)-CuAlO2.

PubMed

Lyu, Lai; Yan, Dengbiao; Yu, Guangfei; Cao, Wenrui; Hu, Chun

2018-04-03

Carbon nitride compounds (CN) complexed with the in-situ-produced Cu(II) on the surface of CuAlO 2 substrate (CN-Cu(II)-CuAlO 2 ) is prepared via a surface growth process for the first time and exhibits exceptionally high activity and efficiency for the degradation of the refractory pollutants in water through a Fenton-like process in a wide pH range. The reaction rate for bisphenol A removal is ∼25 times higher than that of the CuAlO 2 . According to the characterization, Cu(II) generation on the surface of CuAlO 2 during the surface growth process results in the marked decrease of the surface oxygen vacancies and the formation of the C-O-Cu bridges between CN and Cu(II)-CuAlO 2 in the catalyst. The electron paramagnetic resonance (EPR) analysis and density functional theory (DFT) calculations demonstrate that the dual reaction centers are produced around the Cu and C sites due to the cation-π interactions through the C-O-Cu bridges in CN-Cu(II)-CuAlO 2 . During the Fenton-like reactions, the electron-rich center around Cu is responsible for the efficient reduction of H 2 O 2 to • OH, and the electron-poor center around C captures electrons from H 2 O 2 or pollutants and diverts them to the electron-rich area via the C-O-Cu bridge. Thus, the catalyst exhibits excellent catalytic performance for the refractory pollutant degradation. This study can deepen our understanding on the enhanced Fenton reactivity for water purification through functionalizing with organic solid-phase ligands on the catalyst surface.

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.

Degradation and Mineralization of Phenol Compounds with Goethite Catalyst and Mineralization Prediction Using Artificial Intelligence

PubMed Central

Tisa, Farhana; Davoody, Meysam; Abdul Raman, Abdul Aziz; Daud, Wan Mohd Ashri Wan

2015-01-01

The efficiency of phenol degradation via Fenton reaction using mixture of heterogeneous goethite catalyst with homogeneous ferrous ion was analyzed as a function of three independent variables, initial concentration of phenol (60 to 100 mg /L), weight ratio of initial concentration of phenol to that of H2O2 (1: 6 to 1: 14) and, weight ratio of initial concentration of goethite catalyst to that of H2O2 (1: 0.3 to 1: 0.7). More than 90 % of phenol removal and more than 40% of TOC removal were achieved within 60 minutes of reaction. Two separate models were developed using artificial neural networks to predict degradation percentage by a combination of Fe3+ and Fe2+ catalyst. Five operational parameters were employed as inputs while phenol degradation and TOC removal were considered as outputs of the developed models. Satisfactory agreement was observed between testing data and the predicted values (R2 Phenol = 0.9214 and R2TOC= 0.9082). PMID:25849556

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.

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.

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.

Effects of clay minerals on diethyl phthalate degradation in Fenton reactions.

PubMed

Chen, Ning; Fang, Guodong; Zhou, Dongmei; Gao, Juan

2016-12-01

Phthalate esters are a group of plasticizers, which are commonly detected in China's soils and surface water. Fenton reactions are naturally occurring and widely applied in the degradation of contaminants. However, limited research was considered the effects of clay minerals on contaminants degradation with OH oxidation. In this study, batch experiments were conducted to investigate the degradation of diethyl phthalate (DEP) in Fenton reactions in the presence of clay minerals, and the effects of clay type, Fe content in clay structure. The results showed the clay adsorption inhibited total degradation of DEP, and Fe content in clay structure played an important role in DEP degradation, including in solution and adsorbed in clay minerals. Clay minerals with less Fe content (<3%) quenched OH radical, while nontronite with Fe content 19.2% improved OH radical generation and accelerated DEP degradation in solution. The degradation of clay-adsorbed DEP was much slower than DEP in solution. Six main products of DEP degradation were identified, including monoethyl phthalate, phthalate acid, hydroxyl diethyl phthalate, etc. This study implied that phthalate ester's degradation would be much slower in natural water than expected in the presence of clay minerals. Copyright © 2016 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)

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).

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.

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.

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.

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.

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.

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.

Enhanced Fenton-like degradation of TCE in sand suspensions with magnetite by NTA/EDTA at circumneutral pH.

PubMed

Wang, Na; Jia, Daqing; Jin, Yaoyao; Sun, Sheng-Peng; Ke, Qiang

2017-07-01

The present study investigated the degradation of trichloroethylene (TCE) in sand suspensions by Fenton-like reaction with magnetite (Fe 3 O 4 ) in the presence of various chelators at circumneutral pH. The results showed that ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) greatly improved the rate of TCE degradation, while [S,S]-ethylenediaminedisuccinic acid (s,s-EDDS), malonate, citrate, and phytic acid (IP6) have minimal effects on TCE degradation. Quenching tests suggested that TCE was mainly degraded by hydroxyl radical (HO · ) attack, with about 90% inhibition on TCE degradation by the addition of HO · scavenger 2-propanol. The presence of 0.1-0.5% Fe 3 O 4 /sand (w/w) contributed to 40% increase in TCE degradation rates. In particular, the use of chelators can avoid high concentrations of H 2 O 2 required for the Fenton-like reaction with Fe 3 O 4 , and moreover improve the stoichiometric efficiencies of TCE degradation to H 2 O 2 consumption. The suitable concentrations of chelators (EDTA and NTA) and H 2 O 2 were suggested to be 0.5 and 20 mM, respectively. Under the given conditions, degradation rate constants of TCE were obtained at 0.360 h -1 with EDTA and 0.526 h -1 with NTA, respectively. Enhanced degradation of TCE and decreased usage of H 2 O 2 in this investigation suggested that Fenton-like reaction of Fe 3 O 4 together with NTA (or EDTA) may be a promising process for remediation of TCE-contaminated groundwater.

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.

The catalytic oxidation of malachite green by the microwave-Fenton processes.

PubMed

Zheng, Huaili; Zhang, Huiqin; Sun, Xiaonan; Zhang, Peng; Tshukudu, Tiroyaone; Zhu, Guocheng

2010-01-01

Catalytic oxidation of malachite green using the microwave-Fenton process was investigated. 0% of malachite green de-colorization using the microwave process and 23.5% of malachite green de-colorization using the Fenton process were observed within 5 minutes. In contrast 95.4% of malachite green de-colorization using the microwave-Fenton was observed in 5 minutes. During the microwave-Fenton process, the optimum operating conditions for malachite green de-colorization were found to be 3.40 of initial pH, 0.08 mmol/L of Fe2+ concentration and 12.5 mmol/L of H2O2 concentration. Confirmatory tests were carried out under the optimum conditions and the COD removal rate of 82.0% and the de-colorization rate of 99.0% were observed in 5 minutes. The apparent kinetics equation of -dC/dt=0.0337 [malachite green]0.9860[Fe2+)]0.8234[H2O2]0.1663 for malachite green de-colorization was calculated, which implied that malachite green was the dominant factor in determining the removal efficiency of malachite green based on microwave-Fenton process.

Removal of refractory organics in nanofiltration concentrates of municipal solid waste leachate treatment plants by combined Fenton oxidative-coagulation with photo--Fenton processes.

PubMed

Li, Jiuyi; Zhao, Lei; Qin, Lele; Tian, Xiujun; Wang, Aimin; Zhou, Yanmei; Meng, Liao; Chen, Yong

2016-03-01

Removal of the refractory organic matters in leachate brines generated from nanofiltration unit in two full-scale municipal solid waste landfill leachate treatment plants was investigated by Fenton oxidative-coagulation and ultraviolet photo - Fenton processes in this study. Fenton oxidative-coagulation was performed under the condition of an initial pH of 5.0 and low H2O2/Fe(2+) ratios. After precipitate separation, the remaining organic constituents were further oxidized by photo - Fenton process. For both leachate brines with varying pollution strength, more than 90% COD and TOC reductions were achieved at H2O2/Fe(2+) dosages of 35 mM/8 mM and 90 mM/10 mM, respectively. The effluent COD ranged 120-160 mg/L under the optimal operating conditions, and the biodegradability was increased significantly. Fenton oxidative-coagulation was demonstrated to contribute nearly 70% overall removal of organic matters. In the combined processes, the efficiency of hydrogen peroxide varied from 216 to 228%, which may significantly reduce the operating cost of conventional Fenton method. Six phthalic acid esters and thirteen polycyclic aromatic hydrocarbons were found in leachate brines, and, on the average, around 80% phthalic acid esters and 90% polycyclic aromatic hydrocarbons were removed by the combined treatments. Copyright © 2015 Elsevier Ltd. 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.

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.

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.

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.

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).

Heterogeneous Fenton-like discoloration of methyl orange using Fe3O4/MWCNTs as catalyst: combination mechanism and affecting parameters

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

Multi-walled carbon nanotubes (MWCNTs) can act not only as a support for Fe3O4 nanoparticles (NPs) but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of Fe3O4 NPs. In this study, Fe3O4 NPs were in situ anchored onto MWCNTs by a moderate co-precipitation method and the as-prepared Fe3O4/MWCNTs nanocomposites were employed as the highly efficient Fenton-like catalysts. The analyses of XRD, FTIR, Raman, FESEM, TEM and HRTEM results indicated the formation of Fe3O4 crystals in Fe3O4/MWCNTs nanocomposites prepared at different conditions and the interaction between Fe3O4 NPs and MWCNTs. Over a wide pH range, the surface of modified MWCNTs possessed negative charges. Based on these results, the possible combination mechanism between Fe3O4 NPs and MWCNTs was discussed and proposed. Moreover, the effects of preparation and catalytic conditions on the Fenton-like catalytic efficiency were investigated in order to gain further insight into the heterogeneous Fenton-like reaction catalyzed by Fe3O4/MWCNTs nanocomposites.

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.

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.

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.

Pulsed discharge plasma induced Fenton-like reactions for the enhancement of the degradation of 4-chlorophenol in water.

PubMed

Hao, Xiaolong; Zhou, Minghua; Xin, Qing; Lei, Lecheng

2007-02-01

To sufficiently utilize chemically active species and enhance the degradation rate and removal efficiency of toxic and biorefractory organic pollutant para-chlorophenol (para-CP), the introductions of iron metal ions (Fe2+/Fe3+) into either pulsed discharge plasma (PDP) process or the PDP process with TiO2 photo-catalyst were tentatively performed. The experimental results showed that under the same experimental condition, the degradation rate and removal efficiency of para-CP were greatly enhanced by the introduction of iron ions (Fe2+/Fe3+) into the PDP process. Moreover, when iron ions and TiO2 were added together in the PDP process, the degradation rate and removal energy of para-CP further improved. The possible mechanism was discussed that the obvious promoting effects were attributed to ferrous ions via plasma induced Fenton-like reactions by UV light irradiation excited and hydrogen peroxide formed in pulsed electrical discharge, resulting in a larger amount of hydroxyl radicals produced from the residual hydrogen peroxide. In addition, the regeneration of ferric ions to ferrous ions facilitates the progress of plasma induced Fenton-like reactions by photo-catalytic reduction of UV light, photo-catalytic reduction on TiO2 surface and electron transfer of quinone intermediates, i.e. 1,4-hydroquinone and 1,4-benzoquinone.

Effect of the carbon coating in Fe-C-TiO(2) photocatalyst on phenol decomposition under UV irradiation via photo-Fenton process.

PubMed

Tryba, Beata; Morawski, Antoni W; Inagaki, Michio; Toyoda, Masahiro

2006-08-01

Fe-C-TiO(2) photocatalysts which contained the residue carbon (0.2-3.3 mass%) were prepared from a mixture of TiO(2) and FeC(2)O(4) through the heating at 673-1173 K in Ar. These photocatalysts did not show a high adsorption of phenol, but they were active in photo-Fenton reactions during decomposition of phenol under UV irradiation with addition of H(2)O(2). It was proved that Fe(2+) governed the photoactivity of Fe-C-TiO(2) photocatalysts, it decreased with heat-treatment temperature above 773 K. For comparison, Fe-TiO(2) photocatalyst was prepared by heating TiO(2) and FeC(2)O(4) at 823 K in air for 3h. Phenol decomposition was going much slower on Fe-TiO(2) photocatalyst in comparison with Fe-C-TiO(2), of which mechanism was different, on the former phenol was decomposed by the radical reaction, on the latter through a complex reaction with iron and intermediates of phenol decomposition. Therefore carbon-coating TiO(2) was found to be advantageous for mounting iron and its application for the phenol decomposition via photo-Fenton process.

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.

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.

[Degradation of 2, 4-dichlorophenol in aqueous solution by ZVI/EDDS/air system].

PubMed

Sun, Qian; Zhou, Hai-Yan; Cao, Meng-Hua; Wu, Lin-Na; Wang, Lin-Ling; Chen, Jing; Lu, Xiao-Hua

2012-11-01

A new oxidation system of Fenton-like system (ZVI/EDDS/Air) has been developed to degrade 2,4-chlorophenols (2,4-DCP) in aqueous solution. The influences of initial conditions, i. e., EDDS concentration, iron dosage, aeration rate, 2,4-DCP concentration and pH as well as reaction temperature on the degradation of 2,4-DCP were studied. The results demonstrated that this ZVI/EDDS/Air system was able to effectively degrade 2,4-DCP in aqueous solution, and the degradation of 2,4-DCP conforms to the pseudo-first-order reaction kinetics equation. Removal of above 99% 2,4-DCP was achieved in ZVI/EDDS/Air system at room temperature and pressure after 1 h reaction when the initial conditions were 2,4-DCP 100 mg x L(-1), EDDS 0.80 mmo x L(-1), ZVI 20 g x L(-1), aeration rate 2 L x (min x L)(-1). Compared with ZVI/EDTA/Air system, ZVI/EDDS/Air system showed higher efficiency in the degradation of 2,4-DCP at ambient circumstance and was more environmentally benign.

Improved sludge dewaterability and hydrolysis performance after pretreatment with Fenton's reagent.

PubMed

Yuan, Hongying; Yang, Yuping; Yuan, Jian; Wang, Yanning; Song, Yameng; Lu, Jingfang; Song, Jianyang

2018-01-01

The dewaterability of excess sludge significantly improved upon pretreatment with Fenton's reagent in this study. After 0.9 g/L of Fe 2+ and 5.0 g/L of H 2 O 2 were added to the sludge, and reacted for 2 h at pH = 4, the specific resistance to filtration (SRF) of the excess sludge decreased from an initial value of 29.74 × 10 12 m/kg to 6.49 × 10 12 m/kg. The factors that affected this improvement in sludge dewaterability as evaluated by SRF reduction showed the following order: H 2 O 2 > pH > Fe 2+ > reaction time. Furthermore, the hydrolysis performance of the sludge under the optimal reaction conditions was investigated. The results indicated that the concentration of soluble chemical oxygen demand in the supernatant increased almost 14 times compared to raw sludge, and the contents of soluble protein and soluble polysaccharide were more than 8 and 17 times higher, respectively, than for the untreated situation. However, the amounts of ammonia nitrogen (NH 4 + -N) and phosphate (PO 4 3- -P) released from the sludge showed different trends: NH 4 + -N increased by 200%, while PO 4 3- -P decreased by 82%. The production of volatile fatty acids (VFAs) from the treated sludge showed that total VFAs increased by 66%, and iso-butylacetic acid was the dominant product among the total VFAs.

Mature landfill leachate treatment by coagulation/flocculation combined with Fenton and solar photo-Fenton processes.

PubMed

Amor, Carlos; De Torres-Socías, Estefanía; Peres, José A; Maldonado, Manuel I; Oller, Isabel; Malato, Sixto; Lucas, Marco S

2015-04-09

This work reports the treatment of a mature landfill leachate through the application of chemical-based treatment processes in order to achieve the discharge legal limits into natural water courses. Firstly, the effect of coagulation/flocculation with different chemicals was studied, evaluating the role of different initial pH and chemicals concentration. Afterwards, the efficiency of two different advanced oxidation processes for leachate remediation was assessed. Fenton and solar photo-Fenton processes were applied alone and in combination with a coagulation/flocculation pre-treatment. This physicochemical conditioning step, with 2 g L(-1) of FeCl3 · 6H2O at pH 5, allowed removing 63% of COD, 80% of turbidity and 74% of total polyphenols. Combining the coagulation/flocculation pre-treatment with Fenton reagent, it was possible to reach 89% of COD removal in 96 h. Moreover, coagulation/flocculation combined with solar photo-Fenton revealed higher DOC (75%) reductions than single solar photo-Fenton (54%). In the combined treatment (coagulation/flocculation and solar photo-Fenton), it was reached a DOC reduction of 50% after the chemical oxidation, with 110 kJ L(-1) of accumulated UV energy and a H2O2 consumption of 116 mM. Toxicity and biodegradability assays were performed to evaluate possible variations along the oxidation processes. After the combined treatment, the leachate under study presented non-toxicity but biodegradability increased. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of the response surface and desirability design to the Lambda-cyhalothrin degradation using photo-Fenton reaction.

PubMed

Colombo, Renata; Ferreira, Tanare C R; Alves, Suellen A; Carneiro, Renato L; Lanza, Marcos R V

2013-03-30

Lambda-cyhalothrin is a potent pyrethroid insecticide used widely in pest management. Detectable levels of the pyrethroid in agricultural watersheds are potentially toxic to aquatic organisms. There is little information in the scientific literature about degradation in aqueous media of the Lambda-cyhalothrin by Advanced Oxidative Process. A mathematical approach for the degradation of this compound has not yet been fully explored… The Central composite design (CCD) and response surface method (RSM) were applied to evaluate and optimize the interactive effects of two operating variables. The initial dosages of H2O2 and Fe(2+) on photo-Fenton degradation of an aqueous solution of Lambda-cyhalothrin in a recirculation flow-through UV photoreactor were used. The remaining concentration of Lambda-cyhalothrin (y1) and the percentage removal of total organic carbon (y2) were the monitored factors since they are dependent parameters of y1 and y2. According to analysis of variances (ANOVA) results, two proposed models can be used to navigate the design space with regression coefficient R(2) - 0.834 and 0.843 for y1 and y2, respectively. A multi-response optimization procedure, based on the global desirability of the factors, was performed to establish the best concentrations of hydrogen peroxide and ferrous sulfate that would allow the most efficient degradation of Lambda-cyhalothrin concomitant with a maximal removal of total organic carbon. The global desirability surface revealed that 0.295 mmol L(-1) of ferrous sulfate and 3.85 mmol L(-1) of hydrogen peroxide were close to the optimum conditions to satisfy both factors simultaneously using minimal amounts of reagents. These photo-Fenton conditions promoted 100% of Lambda-cyhalothrin degradation and 79.83% TOC removal (mineralization) in 120 min of reaction time. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

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.

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.

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.

Effect of Photo-Fenton Bleaching on Tetracycline-stained Dentin in vitro.

PubMed

Bennett, Zackary Yale; Walsh, Laurence James

2015-02-01

Tetracycline-stained tooth structure is difficult to bleach using nightguard tray methods. The possible benefits of in-office light-accelerated bleaching systems based on the photo-Fenton reaction are of interest as possible adjunctive treatments. This study was a proof of concept for possible benefits of this approach, using dentine slabs from human tooth roots stained in a reproducible manner with the tetracycline antibiotic demeclocycline hydrochloride. Color changes overtime in tetra-cycline stained roots from single rooted teeth treated using gel (Zoom! WhiteSpeed(®)) alone, blue LED light alone, or gel plus light in combination were tracked using standardized digital photography. Controls received no treatment. Changes in color channel data were tracked overtime, for each treatment group (N = 20 per group). Dentin was lighter after bleaching, with significant improvements in the dentin color for the blue channel (yellow shade) followed by the green channel and luminosity. The greatest changes occurred with gel activated by light (p < 0.0001), which was superior to effects seen with gel alone. Use of the light alone did not significantly alter shade. This proof of concept study demonstrates that bleaching using the photo-Fenton chemistry is capable of lightening tetracycline-stained dentine. Further investigation of the use of this method for treating tetracycline-stained teeth in clinical settings appears warranted. Because tetracycline staining may respond to bleaching treatments based on the photo-Fenton reaction, systems, such as Zoom! WhiteSpeed, may have benefits as adjuncts to home bleaching for patients with tetracycline-staining.

NiFe(C2O4)x as a heterogeneous Fenton catalyst for removal of methyl orange.

PubMed

Liu, Yucan; Zhang, Guangming; Chong, Shan; Zhang, Nan; Chang, Huazhen; Huang, Ting; Fang, Shunyan

2017-05-01

This paper studies a heterogeneous Fenton catalyst NiFe(C 2 O 4 ) x , which showed better catalytic activity than Ni(C 2 O 4 ) x and better re-usability than Fe(C 2 O 4 ) x . The methyl orange removal efficiency was 98% in heterogeneous Fenton system using NiFe(C 2 O 4 ) x . The prepared NiFe(C 2 O 4 ) x had a laminated shape and the size was in the range of 2-4 μm, and Ni was doped into catalyst's structure successfully. The NiFe(C 2 O 4 ) x had a synergistic effect of catalyst of 24.7 for methyl orange removal, and the dope of Ni significantly reduced the leaching of Fe by 77%. The reaction factors and kinetics were investigated. Under the optimal conditions, 0.4 g/L of catalyst dose and 10 mmol/L of hydrogen peroxide concentration, 98% of methyl orange was removed within 20 min. Analysis showed that hydroxyl radicals and superoxide radicals participated in the reaction. With NiFe(C 2 O 4 ) x catalyst, the suitable pH range for heterogeneous Fenton system was wide from 3 to 10. The catalyst showed good efficiency after five times re-use. NiFe(C 2 O 4 ) x provided great potential in treatment of refractory wastewater with excellent property. Copyright © 2017 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.

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.

Synergistic operation of photocatalytic degradation and Fenton process by magnetic Fe3O4 loaded TiO2

NASA Astrophysics Data System (ADS)

Sun, Qiong; Hong, Yong; Liu, Qiuhong; Dong, Lifeng

2018-02-01

The magnetic Fe3O4 loaded anatase TiO2 photocatalysts with different mass ratios were successfully synthesized by a one-step convenient calcining method. The morphology and structure analysis revealed that Fe3O4 was formed in TiO2 with very fine-grained particles. After a small amount of Fe3O4 loaded onto TiO2, the photocatalytic property enhanced obviously for the degradation of organic dye. Furthermore, the photo-Fenton-like catalysis of the iron-containing samples could also be induced after the addition of hydrogen peroxide. The apparent kinetic constant of the reaction that catalyzed by Fe-TiO2 was about 5.3 and 8.3 times of that catalyzed by TiO2 or Fe3O4 only, respectively, proving an effective synergistic contribution of the photocatalysis and Fenton reaction in the composite. Compared with Fe3O4 or free Fe3+ ions, only 13% of iron in TiO2 dissolved into acidic solution (25% for Fe3O4 and 100% for Fe3+) after the reaction, which confirmed the iron had been well immobilized onto TiO2. In addition, the extremely stable photocatalytic activity in cycling experiments proved the immobilized iron had been tightly attached onto TiO2, indicating the great potential of the catalyst for practical applications.

Protective role of quercetin against copper(II)-induced oxidative stress: A spectroscopic, theoretical and DNA damage study.

PubMed

Jomova, Klaudia; Lawson, Michael; Drostinova, Lenka; Lauro, Peter; Poprac, Patrik; Brezova, Vlasta; Michalik, Martin; Lukes, Vladimir; Valko, Marian

2017-12-01

The radical scavenging and metal chelating properties of flavonoids indicate that they may play a protective role in diseases with perturbed metal homeostasis such as Alzheimer's disease. In this work we investigated the effect of the coordination of quercetin to copper(II) in view of the formation of ROS in Cu-catalyzed Fenton reaction. ABTS and DPPH assays confirmed that the copper(II)-quercetin complex exhibits a stronger radical scavenging activity than does quercetin alone. EPR spin trapping experiments have shown that chelation of quercetin to copper significantly suppressed the formation of hydroxyl radicals in the Cu(II)-Fenton reaction. DNA damage experiments revealed a protective effect for quercetin, but only at higher stoichiometric ratios of quercetin relative to copper. DNA protective effect of quercetin against ROS attack was described by two mechanisms. The first mechanism lies in suppressed formation of ROS due to the decreased catalytic action of copper in the Fenton reaction, as a consequence of its chelation and direct scavenging of ROS by free quercetin. Since the Cu-quercetin complex intercalates into DNA, the second mechanism was attributed to a suppressed intercalating ability of the Cu-quercetin complex due to the mildly intercalating free quercetin into DNA, thus creating a protective wall against stronger intercalators. Copyright © 2017 Elsevier Ltd. All rights reserved.

TCE degradation in groundwater by chelators-assisted Fenton-like reaction of magnetite: Sand columns demonstration.

PubMed

Jia, Daqing; Sun, Sheng-Peng; Wu, Zhangxiong; Wang, Na; Jin, Yaoyao; Dong, Weiyang; Chen, Xiao Dong; Ke, Qiang

2018-03-15

Trichloroethylene (TCE) degradation in sand columns has been investigated to evaluate the potential of chelates-enhanced Fenton-like reaction with magnetite as iron source for in situ treatment of TCE-contaminated groundwater. The results showed that successful degradation of TCE in sand columns was obtained by nitrilotriacetic acid (NTA)-assisted Fenton-like reaction of magnetite. Addition of ethylenediaminedisuccinic acid (EDDS) resulted in an inhibitory effect on TCE degradation in sand columns. Similar to EDDS, addition of ethylenediaminetetraacetic acid (EDTA) also led to an inhibition of TCE degradation in sand column with small content of magnetite (0.5 w.t.%), but enhanced TCE degradation in sand column with high content of magnetite (7.0 w.t.%). Additionally, the presence of NTA, EDDS and EDTA greatly decreased H 2 O 2 uptake in sand columns due to the competition between chelates and H 2 O 2 for surface sites on magnetite (and sand). Furthermore, the presented results show that magnetite in sand columns remained stable in a long period operation of 230 days without significant loss of performance in terms of TCE degradation and H 2 O 2 uptake. Moreover, it was found that TCE was degraded mainly to formic acid and chloride ion, and the formation of chlorinated organic intermediates was minimal by this process. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

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.

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.

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.

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.

Fe1-xZnxS ternary solid solution as an efficient Fenton-like catalyst for ultrafast degradation of phenol.

PubMed

Gao, Jing; Liu, Yutang; Xia, Xinnian; Wang, Longlu; Dong, Wanyue

2018-07-05

Heterogeneous Fenton-like system has been proved to be an promising alternative to Fenton system due to its easy separation. However, it's a challenge to design heterogeneous Fenton-like catalysts with high activity and great durability. Here, ternary solid solution Fe 1-x Zn x S were prepared via hydrothermal synthesis as heterogeneous Fenton-like catalysts. The Fe 0.7 Zn 0.3 S sample exhibited state of the art activity for yielding OH by H 2 O 2 decomposition, and the ultrafast degradation of phenol was achieved in 4 min at initial acidic condition under room temperature. The phenol degradation rate constant of Fe 0.7 Zn 0.3 S was 99 and 70 times of ZnS and FeS, respectively. Further, we show that the unique structural configuration of iron atoms, the formation of FeS 2 -pyrite with (200) plane, are responsible for the excellent activity. The intermediate products were identified by LC-MS and a possible pathway was accordingly proposed to elucidate the mechanism of phenol degradation by OH. Overall, this work provides an idea for the rational design of the relevant heterogeneous Fenton-like catalysts. Copyright © 2018 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,...

Landfill leachate treatment by solar-driven AOPs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocha, Elisangela M.R.; Vilar, Vitor J.P.; Boaventura, Rui A.R.

2011-01-15

Sanitary landfill leachate resulting from the rainwater percolation through the landfill layers and waste material decomposition is a complex mixture of high-strength organic and inorganic compounds which constitutes serious environmental problems. In this study, different heterogeneous (TiO{sub 2}/UV, TiO{sub 2}/H{sub 2}O{sub 2}/UV) and homogenous (H{sub 2}O{sub 2}/UV, Fe{sup 2+}/H{sub 2}O{sub 2}/UV) photocatalytic processes were investigated as an alternative for the treatment of a mature landfill leachate. The addition of H{sub 2}O{sub 2} to TiO{sub 2}/UV system increased the reduction of the aromatic compounds from 15% to 61%, although mineralization was almost the same. The DOC and aromatic content abatement ismore » similar for the H{sub 2}O{sub 2}/UV and TiO{sub 2}/H{sub 2}O{sub 2}/UV processes, although the H{sub 2}O{sub 2} consumption is three times higher in the H{sub 2}O{sub 2}/UV system. The low efficiency of TiO{sub 2}/H{sub 2}O{sub 2}/UV system is presumably due to the alkaline leachate solution, for which the H{sub 2}O{sub 2} becomes highly unstable and self-decomposition of H{sub 2}O{sub 2} occurs. The efficiency of the TiO{sub 2}/H{sub 2}O{sub 2}/UV system increased 10 times after a preliminary pH correction to 4. The photo-Fenton process is much more efficient than heterogeneous (TiO{sub 2}, TiO{sub 2}/H{sub 2}O{sub 2}/UV) or homogeneous (H{sub 2}O{sub 2}/UV) photocatalysis, showing an initial reaction rate more than 20 times higher, and leading to almost complete mineralization of the wastewater. However, when compared with TiO{sub 2}/H{sub 2}O{sub 2}/UV with acidification, the photo-Fenton reaction is only two times faster. The optimal initial iron dose for the photo-Fenton treatment of the leachate is 60 mg Fe{sup 2+} L{sup -1}, which is in agreement with path length of 5 cm in the photoreactor. The kinetic behaviour of the process (60 mg Fe{sup 2+} L{sup -1}) comprises a slow initial reaction, followed by a first-order kinetics (k = 0.020 LkJ{sub UV}{sup -1}, r{sub 0} = 12.5 mg kJ{sub UV}{sup -1}), with H{sub 2}O{sub 2} consumption rate of k{sub H2O2} = 3.0 mmol H{sub 2}O{sub 2}kJ{sub UV}{sup -1}, and finally, the third reaction period, characterized by a lower DOC degradation and H{sub 2}O{sub 2} consumption until the end of the experiment, presumably due to the formation of low-molecular-weight carboxylic groups. A total of 306 mM of H{sub 2}O{sub 2} was consumed for achieving 86% mineralization (DOC{sub final} = 134 mg L{sup -1}) and 94% aromatic content reduction after 110 kJ{sub UV} L{sup -1}, using an initial iron concentration of 60 mg Fe{sup 2+} L{sup -1}. (author)« less

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.

Inhibition of hydroxyl radical reaction with aromatics by dissolved natural organic matter

USGS Publications Warehouse

Lindsey, M.E.; Tarr, M.A.

2000-01-01

Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compound molecules bound to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H2O2 + Fe2+ ??? Fe3+ + HO- + HO??). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanism for the observed inhibition is that hydroxyl radical formation occurs in microenvironmental sites remote from the aromatic compounds. In addition to changes in kinetics, pyrene hydroxyl radical reaction also exhibited a mechanistic change in the presence of fulvic acid. The mechanism changed from a reaction that was apparently firstorder in pyrene to one that was apparently secondorder in pyrene, indicating that pyrene self-reaction may have become the dominant mechanism in the presence of fulvic acid. Dissolved NOM causes significant changes in the rate and mechanism of hydroxyl radical degradation of aromatic compounds. Consequently, literature rate constants measured in pure water will not be useful for predicting the degradation of pollutants in environmental systems. The kinetic and mechanistic information in this study will be useful for developing improved degradation methods involving Fenton chemistry.Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compounds molecules bounds to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H2O2 + Fe2+ ??? Fe3+ + HO- + HO??). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanisms for the observed inhibition is that hydroxyl radical formation occurs in microenvironmental sites remote from the aromatic compounds. In addition to changes in kinetics, pyrene hydroxyl radical reaction also exhibited a mechanistic change in the presence of fulvic acid. The mechanism changed from a reaction that was apparently first-order in pyrene to one that was apparently second-order in pyrene, indicating that pyrene self-reaction may have become the dominant mechanism in the presence of fulvic acid. Dissolved NOM causes significant changes in the rate and mechanism of hydroxyl radical degradation of aromatic compounds. Consequently, literature rate constants measured in pure water will not be useful for predicting the degradation of pollutants in environmental systems. The kinetic and mechanistic information in this study will be useful for developing improved degradation methods involving Fenton chemistry.

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.

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.

Myricetin-induced apoptosis of triple-negative breast cancer cells is mediated by the iron-dependent generation of reactive oxygen species from hydrogen peroxide.

PubMed

Knickle, Allison; Fernando, Wasundara; Greenshields, Anna L; Rupasinghe, H P Vasantha; Hoskin, David W

2018-05-06

Myricetin is a dietary phytochemical with anticancer activity; however, the effect of myricetin on breast cancer cells remains unclear. Here, we show that myricetin inhibited the growth of triple-negative breast cancer (TNBC) cells but was less inhibitory for normal cells. The effect of myricetin was comparable to epigallocatechin gallate and doxorubicin, and greater than resveratrol and cisplatin. Myricetin-treated TNBC cells showed evidence of early and late apoptosis/necrosis, which was associated with intracellular reactive oxygen species (ROS) accumulation, extracellular regulated kinase 1/2 and p38 mitogen-activated protein kinase activation, mitochondrial membrane destabilization and cytochrome c release, and double-strand DNA breaks. The antioxidant N-acetyl-cysteine protected myricetin-treated TNBC cells from cytotoxicity due to DNA damage. Myricetin also induced hydrogen peroxide (H 2 O 2 ) production in cell-free culture medium, as well as in the presence of TNBC cells and normal cells. In addition, deferriprone-mediated inhibition of intracellular ROS generation via the iron-dependent Fenton reaction and inhibition of extracellular ROS accumulation with superoxide dismutase plus catalase prevented myricetin-induced cytotoxicity in TNBC cell cultures. We conclude that the cytotoxic effect of myricetin on TNBC cells was due to oxidative stress initiated by extracellular H 2 O 2 formed by autoxidation of myricetin, leading to intracellular ROS production via the Fenton reaction. Copyright © 2018. Published by Elsevier Ltd.

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.

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.

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.

Learning about Regiochemistry from a Hydrogen-Atom Abstraction Reaction in Water

ERIC Educational Resources Information Center

Sears-Dundes, Christopher; Huon, Yoeup; Hotz, Richard P.; Pinhas, Allan R.

2011-01-01

An experiment has been developed in which the hydrogen-atom abstraction and the coupling of propionitrile, using Fenton's reagent, are investigated. Students learn about the regiochemistry of radical formation, the stereochemistry of product formation, and the interpretation of GC-MS data, in a safe reaction that can be easily completed in one…

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.

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.

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 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.

Sodium ascorbate kills Candida albicans in vitro via iron-catalyzed Fenton reaction: importance of oxygenation and metabolism

PubMed Central

Avci, Pinar; Freire, Fernanda; Banvolgyi, Andras; Mylonakis, Eleftherios; Wikonkal, Norbert M; Hamblin, Michael R

2016-01-01

Aim: Ascorbate can inhibit growth and even decrease viability of various microbial species including Candida albicans. However the optimum conditions and the mechanism of action are unclear. Materials/methodology: Candida albicans shaken for 90 min in a buffered solution of ascorbate (90 mM) gave a 5-log reduction of cell viability, while there was no killing without shaking, in growth media with different carbon sources or at 4°C. Killing was inhibited by the iron chelator 2,2′-bipyridyl. Hydroxyphenyl fluorescein probe showed the intracellular generation of hydroxyl radicals. Results/conclusion: Ascorbate-mediated killing of C. albicans depends on oxygenation and metabolism, involves iron-catalyzed generation of hydroxyl radicals via Fenton reaction and depletion of intracellular NADH. Ascorbate could serve as a component of a topical antifungal therapy. PMID:27855492

Highly concentrated phenolic wastewater treatment by heterogeneous and homogeneous photocatalysis: mechanism study by FTIR-ATR.

PubMed

Araña, J; Tello-Rendón, E; Doña-Rodríguez, J M; Campo, C V; Herrera-Melidán, J A; González-Díaz; Pérez-Peña, J

2001-01-01

The degradation of high phenol concentrations (1 g/L) in water solutions by TiO2 photocatalysis and the photo-Fenton reaction has been studied. From the obtained data it may be suggested that degradation of phenol by TiO2-UV takes place onto the catalyst surface by means of peroxo-compounds formation. At low phenol concentrations other mechanism, the insertion of OH. radicals, may be favored. On the other hand, highly concentrated phenol aqueous solutions treatment by the photo-Fenton reaction gives rise to the formation of polyphenolic polymers. These seem to reduce the process rate. Degradation intermediates have been identified by HPLC and FTIR. The FTIR study of the catalyst surface has shown infrared bands attributable to different chemisorbed peroxo-compounds, formates, ortho-formates and carboxylates that can inactivate the catalyst.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Te-Chang; Institute of Pharmacology, Yang Min University, Taipei, Taiwan; Cheng, I-Cheng

Arsenic trioxide (ATO) treatment is a useful therapy against human acute promyelocytic leukemia (APL), however, it concomitantly brings potential adverse consequences including serious side effect, human carcinogenicity and possible development of resistance. This investigation revealed that those problems might be relaxed by simultaneous application with (-)-epigallocatechin-3-gallate (EGCG), one of the major components from green tea. EGCG significantly lowered down the ATO concentration required for an effective control of APL cells, HL-60. The simultaneous treatment of ATO with EGCG induced a mitochondria-dependent apoptosis in HL-60 cells significantly, which accounted for more than 70% of the cell death in the treatment. Themore » mechanism of apoptosis induction was elucidated. EGCG in HL-60 cells acted as a pro-oxidant enhancing intracellular hydrogen peroxide significantly. ATO, on the other hand, induced heme oxygenase-1 (HO-1) to catalyze heme degradation, thereby provided ferrous iron for EGCG-induced hydrogen peroxide to precede Fenton reaction, which in turn generated deleterious reactive oxygen species to damage cell. In addition, EGCG inhibited expression of ferritin, which supposedly to sequester harmful ferrous iron, thereby augmented the occurrence of Fenton reaction. This investigation also provided evidence that ATO, since mainly acted to induce HO-1 in simultaneous treatment with EGCG, could be replaced by other HO-1 inducer with much less human toxicity. Furthermore, several of our preliminary investigations revealed that the enhanced cytotoxicity induced by combining heme degradation and Fenton reaction is selectively toxic to malignant but not non-malignant cells.« less

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.

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.

Degradation of organic dyes by a new heterogeneous Fenton reagent - Fe2GeS4 nanoparticle.

PubMed

Shi, Xiaoguo; Tian, Ang; You, Junhua; Yang, He; Wang, Yuzheng; Xue, Xiangxin

2018-07-05

The heterogeneous Fenton system has become the hotspot in the decontamination field due to its effective degradation performance with a wide pH range. Based on the unstable chemical properties of pyrite, in this article, Fe 2 GeS 4 nanoparticles with better thermodynamic stability were prepared by vacuum sintering and high energy ball milling and its potential as Fenton reagent was investigated for the first time. Three determinants of the heterogeneous Fenton system including the iron source, hydrogen peroxide, pH and the degradation mechanism were investigated. The catalyst dosage of 0.3 g/L, initial H 2 O 2 concentration in the Fenton system of 50 m mol/L and pH of 7 were chosen as the best operational conditions. An almost complete degradation was achieved within 5 min for methylene blue and rhodamine b while 10 min for methyl orange. The total organic carbon removal efficiencies of Fe 2 GeS 4 heterogeneous Fenton system for methylene blue, methyl orange and rhodamine b in 10 min were 56.3%, 66.2% and 74.2%, respectively. It's found that the degradation ability could be attributed to a heterogeneous catalysis occurring at the Fe 2 GeS 4 surface together with a homogeneous catalysis in the aqueous phase by the dissolved iron ions. Copyright © 2018 Elsevier B.V. All rights reserved.

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

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.

Nanoparticle-assisted photo-Fenton reaction for photo-decomposition of humic acid

NASA Astrophysics Data System (ADS)

Banik, Jhuma; Basumallick, Srijita

2017-11-01

We report here the synthesis of CuO-doped ZnO composite nanomaterials (NMs) by chemical route and demonstrated for the first time that these NMs are efficient catalysts for H2O2-assisted photo-decomposition (photo-Fenton type catalyst) of humic acid, a natural pollutant of surface water by solar irradiation. This has been explained by faster electron transfer to OH radical at the p-n hetero-junction of this composite catalyst. Application of this composite catalyst in decomposing humus substances of local pond water by solar energy has been demonstrated.

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.

Prevention of acetic acid-induced colitis by desferrithiocin analogs in a rat model.

PubMed

Bergeron, Raymond J; Wiegand, Jan; Weimar, William R; Nguyen, John Nhut; Sninsky, Charles A

2003-02-01

Iron contributes significantly to the formation of reactive oxygen species via the Fenton reaction. Therefore, we assessed whether a series of desferrithiocin analogs, both carboxylic acids and hydroxamates, could (1) either promote or diminish the iron-mediated oxidation of ascorbate, (2) quench a model radical species, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), and (3) when applied topically, prevent acetic acid-induced colitis in rats. Surprisingly, most of the desferrithiocin analogs inhibited the Fenton reaction to an approximately equivalent degree; however, substantial differences were observed in the capacity of the analogs to scavenge the model radical cation. Four carboxylic acid desferrithiocin analogs and their respective N-methylhydroxamates were tested along with desferrioxamine and Rowasa, a currently accepted topical therapeutic agent for inflammatory bowel disease (IBD), in a rodent model of acetic acid-induced colitis. The colonic damage was quantitated by two independent measurements. Although neither radical scavenging nor prevention of Fenton chemistry was a definitive predictor of in vivo efficacy, the overall trend is that desferrithiocin analogs substituted with an N-methylhydroxamate in the place of the carboxylic acid are both better free radical scavengers and more active against acetic acid-induced colitis. These results represent an intriguing alternative avenue to the development of improved IBD therapeutic agents.

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.

Degradation of ethylenethiourea pesticide metabolite from water by photocatalytic processes.

PubMed

Bottrel, Sue Ellen C; Amorim, Camila C; Leão, Mônica M D; Costa, Elizângela P; Lacerda, Igor A

2014-01-01

In this study, photocatalytic (photo-Fenton and H2O2/UV) and dark Fenton processes were used to remove ethylenethiourea (ETU) from water. The experiments were conducted in a photo-reactor with an 80 W mercury vapor lamp. The mineralization of ETU was determined by total organic carbon analysis, and ETU degradation was qualitatively monitored by the reduction of UV absorbance at 232 nm. A higher mineralization efficiency was obtained by using the photo-peroxidation process (UV/H2O2). Approximately 77% of ETU was mineralized within 120 min of the reaction using [H2O2]0 = 400 mg L(-1). The photo-Fenton process mineralized 70% of the ETU with [H2O2]0 = 800 mg L(-1) and [Fe(2+)] = 400 mg L(-1), and there is evidence that hydrogen peroxide was the limiting reagent in the reaction because it was rapidly consumed. Moreover, increasing the concentration of H2O2 from 800 mg L(-1) to 1200 mg L(-1) did not enhance the degradation of ETU. Kinetics studies revealed that the pseudo-second-order model best fit the experimental conditions. The k values for the UV/H2O2 and photo-Fenton processes were determined to be 6.2 × 10(-4) mg L(-1) min(-1) and 7.7 × 10(-4) mg L(-1) min(-1), respectively. The mineralization of ETU in the absence of hydrogen peroxide has led to the conclusion that ETU transformation products are susceptible to photolysis by UV light. These are promising results for further research. The processes that were investigated can be used to remove pesticide metabolites from drinking water sources and wastewater in developing countries.

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.

Electrochemistry in the mimicry of oxidative drug metabolism by cytochrome P450s.

PubMed

Nouri-Nigjeh, Eslam; Bischoff, Rainer; Bruins, Andries P; Permentier, Hjalmar P

2011-05-01

Prediction of oxidative drug metabolism at the early stages of drug discovery and development requires fast and accurate analytical techniques to mimic the in vivo oxidation reactions by cytochrome P450s (CYP). Direct electrochemical oxidation combined with mass spectrometry, although limited to the oxidation reactions initiated by charge transfer, has shown promise in the mimicry of certain CYP-mediated metabolic reactions. The electrochemical approach may further be utilized in an automated manner in microfluidics devices facilitating fast screening of oxidative drug metabolism. A wide range of in vivo oxidation reactions, particularly those initiated by hydrogen atom transfer, can be imitated through the electrochemically-assisted Fenton reaction. This reaction is based on O-O bond activation in hydrogen peroxide and oxidation by hydroxyl radicals, wherein electrochemistry is used for the reduction of molecular oxygen to hydrogen peroxide, as well as the reduction of Fe(3+) to Fe(2+). Metalloporphyrins, as surrogates for the prosthetic group in CYP, utilizing metallo-oxo reactive species, can also be used in combination with electrochemistry. Electrochemical reduction of metalloporphyrins in solution or immobilized on the electrode surface activates molecular oxygen in a manner analogous to the catalytical cycle of CYP and different metalloporphyrins can mimic selective oxidation reactions. Chemoselective, stereoselective, and regioselective oxidation reactions may be mimicked using electrodes that have been modified with immobilized enzymes, especially CYP itself. This review summarizes the recent attempts in utilizing electrochemistry as a versatile analytical and preparative technique in the mimicry of oxidative drug metabolism by CYP. © 2011 Bentham Science Publishers Ltd.

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...

Enhanced bioethanol production by fed-batch simultaneous saccharification and co-fermentation at high solid loading of Fenton reaction and sodium hydroxide sequentially pretreated sugarcane bagasse.

PubMed

Zhang, Teng; Zhu, Ming-Jun

2017-04-01

A study on the fed-batch simultaneous saccharification and co-fermentation (SSCF) of Fenton reaction combined with NaOH pretreated sugarcane bagasse (SCB) at a high solid loading of 10-30% (w/v) was investigated. Enzyme feeding mode, substrate feeding mode and combination of both were compared with the batch mode under respective solid loadings. Ethanol concentrations of above 80g/L were obtained in batch and enzyme feeding modes at a solid loading of 30% (w/v). Enzyme feeding mode was found to increase ethanol productivity and reduce enzyme loading to a value of 1.23g/L/h and 9FPU/g substrate, respectively. The present study provides an economically feasible process for high concentration bioethanol production. Copyright © 2017 Elsevier Ltd. 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.

Facile synthesis of three-dimensional diatomite/manganese silicate nanosheet composites for enhanced Fenton-like catalytic degradation of malachite green dye

NASA Astrophysics Data System (ADS)

Jiang, De Bin; Yuan, Yunsong; Zhao, Deqiang; Tao, Kaiming; Xu, Xuan; Zhang, Yu Xin

2018-05-01

In this work, we demonstrate a novel and simple approach for fabrication of the complex three-dimensional (3D) diatomite/manganese silicate nanosheet composite (DMSNs). The manganese silicate nanosheets are uniformly grown on the inner and outer surface of diatomite with controllable morphology using a hydrothermal method. Such structural features enlarged the specific surface area, resulting in more catalytic active sites. In the heterogeneous Fenton-like reaction, the DMSNs exhibited excellent catalytic capability for the degradation of malachite green (MG). Under optimum condition, 500 mg/L MG solution was nearly 93% decolorized at 70 min in the reaction. The presented results show an enhanced catalytic behavior of the DMSNs prepared by the low-cost natural diatomite material and simple controllable process, which indicates their potential for environmental remediation applications. [Figure not available: see fulltext.

Facile hydrothermal synthesis of Fe3O4@cellulose aerogel nanocomposite and its application in Fenton-like degradation of Rhodamine B.

PubMed

Jiao, Yue; Wan, Caichao; Bao, Wenhui; Gao, He; Liang, Daxin; Li, Jian

2018-06-01

A magnetic cellulose aerogel-supported Fe 3 O 4 nanoparticles composite was designed as a highly efficient and eco-friendly catalyst for Fenton-like degradation of Rhodamine B (RhB). The composite (coded as Fe 3 O 4 @CA) was formed by embedding well-dispersed Fe 3 O 4 nanoparticles into the 3D structure of cellulose aerogels by virtue of a facile and cheap hydrothermal method. Comparative studies indicate that the RhB decolorization ratio is much higher in co-presence of Fe 3 O 4 and H 2 O 2 than that in presence of Fe 3 O 4 or H 2 O 2 only, revealing that the Fe 3 O 4 @CA-catalyzed Fenton-like reaction governed the RhB decolorization process. It was also found that almost 100% RhB removal was achieved in the Fenton-like system. Moreover, the composite exhibited higher catalytic activity than that of the individual Fe 3 O 4 particles. In addition, the Fe 3 O 4 @CA catalyst retained ∼97% of its ability to degrade RhB after the six successive degradation experiments, suggesting its excellent reusability. All these merits indicate that the green and low-cost catalyst with strong magnetic responsiveness possesses good potential for H 2 O 2 -driven Fenton-like treatment of organic dyestuff wastewater. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Investigation on pretreatment of centrifugal mother liquid produced in the production of polyvinyl chloride by air-Fenton technique.

PubMed

Sun, Yingying; Hua, Xiuyi; Ge, Rui; Guo, Aitong; Guo, Zhiyong; Dong, Deming; Sun, Wentian

2013-08-01

Centrifugal mother liquid (CML) is one of the main sources of wastewater produced during the production of polyvinyl chloride in chlor-alkali industry. CML is a typical poorly biodegradable organic wastewater, containing many kinds of refractory pollutants. Specifically, it contains dissolved refractory polymers, especially polyvinyl alcohol (PVA), which can pass though the biotreatment processes and clog the membranes used for further treatment. In this study, to ensure the CML applicable to biotreatment and membrane treatment, a novel efficient and mild technique, air-Fenton treatment, was employed as a pretreatment technique to improve biodegradability of the CML and to break down the polymers in the CML. Firstly, the technique was optimized for the CML treatment by optimizing the main parameters, including the dosage of ferrous sulfate, initial pH of the wastewater, [H2O2]/[Fe(2+)], aeration rate, reaction time, and temperature, based on removal efficiency of COD and PVA from the CML. Then, the optimized technique was tested and evaluated. The results indicated that under the optimized conditions, the air-Fenton treatment could remove 66, 98, and 55 % of the COD, PVA, and TOC, respectively, from the CML. After the treatment, biodegradability of the wastewater increased significantly (BOD/COD increased from 0.31 to 0.68), and almost all of the PVA polymers were removed or broken down. Meanwhile, concentration of the remaining iron ions, which were added during the treatment, was also quite low (only 2.9 mg/L). Furthermore, most of the suspended materials and ammonia nitrogen, and some of the phosphorus in the wastewater were removed simultaneously.

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.

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.

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.

Insights into solar photo-Fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab-scale.

PubMed

Silva, Tânia F C V; Ferreira, Rui; Soares, Petrick A; Manenti, Diego R; Fonseca, Amélia; Saraiva, Isabel; Boaventura, Rui A R; Vilar, Vítor J P

2015-12-01

This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe(2+)/L), solution pH (2.0-3.6), operating temperature (10-50 °C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH(2+), was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH(2+). The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 °C; [Fe(2+)] = 60 mg/L and UV irradiance = 44 WUV/m(2), achieving 72% mineralization after 25 kJUV/L of accumulated UV energy and 149 mM of H2O2 consumed. Copyright © 2015 Elsevier Ltd. All rights reserved.

ROLE OF THE PHOTO-FENTON REACTION IN THE PRODUCTION OF HYDROXYL RADICALS AND PHOTOBLEACHING OF COLORED DISSOLVED ORGANIC MATTER IN A COASTAL RIVER OF THE SOUTHEASTERN UNITED STATES

EPA Science Inventory

Photochemical reactions involving colored dissolved organic matter (CDOM) in natural waters are important determinants of nutrient cycling, trace gas production and control of light penetration into the water column. In this study the role of the hydroxyl radical ((OH)-O-.) in CD...

Heterogeneous electro-Fenton using modified iron-carbon as catalyst for 2,4-dichlorophenol degradation: influence factors, mechanism and degradation pathway.

PubMed

Zhang, Chao; Zhou, Minghua; Ren, Gengbo; Yu, Xinmin; Ma, Liang; Yang, Jie; Yu, Fangke

2015-03-01

Modified iron-carbon with polytetrafluoroethylene (PTFE) was firstly investigated as heterogeneous electro-Fenton (EF) catalyst for 2,4-dichlorophenol (2,4-DCP) degradation in near neutral pH condition. The catalyst was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), and the effects of some important operating parameters such as current intensity and pH on the 2,4-DCP degradation were investigated. After the catalyst modification with 20% PTFE, the degradation performance maintained well with much lower iron leaching, and at current intensity 100 mA, initial pH 6.7, catalyst loading 6 g/L, the degradation efficiency of 2,4-DCP could exceed 95% within 120 min treatment. Two-stage pseudo first-order kinetics of 2,4-DCP degradation was observed, including a slow anodic oxidation stage (first-stage) and much faster heterogeneous EF oxidation (second-stage), in which the automatic drop of pH in the first-stage initiated the Fe(2+) release from micro-electrolysis and thus benefited to the subsequent EF reaction. Aromatic intermediates such as 3,5-dichlorocatechol, 4,6-dichlororesorcinol and 2-chlorohydroquinone were detected by GC-MS. Oxalic acid, acetic acid, formic acid and Cl(-) were quantified by ion chromatograph. Based on these analysis as well as the detection of H₂O₂ and OH, a possible mechanism and degradation pathway for 2,4-DCP were proposed. This work demonstrated that such a heterogeneous EF using cheap modified Fe-C catalyst was promising for organic wastewater treatment in initial neutral pH condition. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

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.

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.

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.

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.

Reactive Secondary Sequence Oxidative Pathology Polymer Model and Antioxidant Tests

PubMed Central

Petersen, Richard C.

2014-01-01

Aims To provide common Organic Chemistry/Polymer Science thermoset free-radical crosslinking Sciences for Medical understanding and also present research findings for several common vitamins/antioxidants with a new class of drugs known as free-radical inhibitors. Study Design Peroxide/Fenton transition-metal redox couples that generate free radicals were combined with unsaturated lipid oils to demonstrate thermoset-polymer chain growth by crosslinking with the α-β-unsaturated aldehyde acrolein into rubbery/adhesive solids. Further, Vitamin A and beta carotene were similarly studied for crosslink pathological potential. Also, free-radical inhibitor hydroquinone was compared for antioxidant capability with Vitamin E. Place and Duration of Study Department of Materials Science and Engineering and Department of Biomaterials, University of Alabama at Birmingham, between June 2005 and August 2012. Methodology Observations were recorded for Fenton free-radical crosslinking of unsaturated lipids and vitamin A/beta carotene by photography further with weight measurements and percent-shrinkage testing directly related to covalent crosslinking of unsaturated lipids recorded over time with different concentrations of acrolein. Also, hydroquinone and vitamin E were compared at concentrations from 0.0–7.3wt% as antioxidants for reductions in percent-shrinkage measurements, n = 5. Results Unsaturated lipid oils responded to Fenton thermoset-polymer reactive secondary sequence reactions only by acrolein with crosslinking into rubbery-type solids and different non-solid gluey products. Further, molecular oxygen crosslinking was demonstrated with lipid peroxidation and acrolein at specially identified margins. By peroxide/Fenton free-radical testing, both vitamin A and beta-carotene demonstrated possible pathology chemistry for chain-growth crosslinking. During lipid/acrolein testing over a 50 hour time period at 7.3wt% antioxidants, hydroquinone significantly reduced percent shrinkage greatly compared to the standard antioxidant vitamin E, %shrinkage at 11.6 ±1.3 for hydroquinone and 27.8 ±2.2 for vitamin E, P = .001. Conclusion Free radicals crosslinked unsaturated lipid fatty acids into thermoset polymers through Fenton reactions when combined with acrolein. Further, hydroquinone was a superior antioxidant to vitamin E. PMID:25909053

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

Contrast Experiment on Advanced Treatment of Pharmaceutical and Paper-making Wastewater through Cinder Fenton-like Process

NASA Astrophysics Data System (ADS)

Xiaofeng, Jia; Xiaoyu, Chen; Wenning, Mai

2018-06-01

The Fenton-like process of catalyzing H2O2 with Fe2+ and cinder is adopted to subject pharmaceutical and paper-making wastewater to advanced treatment. The influence of each factor is determined using orthogonal experiment and single factor test. The optimal combination of influencing factors is 0.3mmol · L-1 of FeSO4 · 7H2O, [H2O2]:[Fe2+]=8:1 and 10g · L-1 of pyrites cinder. The reaction time in pharmaceutical wastewater and paper-making wastewater is 30min and 60min respectively, testifying to the fact that the reaction in pharmaceutical wastewater is faster than that in paper-making wastewater and the lower utilization rate of cinder in pharmaceutical wastewater. Under the optimal reaction condition, the COD removal rate of these two kinds of wastewater can reach as high as 65% and 72%. Characterized by simple operation and requiring less reagent dosage, this method does not have to regulate the pH of flooding water and allows the repeated usage of cinder.

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.

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.

Further insights into the oxidation chemistry and biochemistry of the serotonergic neurotoxin 5,6-dihydroxytryptamine.

PubMed

Singh, S; Dryhurst, G

1990-11-01

The neurodegenerative properties of the serotonergic neurotoxin 5,6-dihydroxytryptamine (5,6-DHT) are widely believed to result from its autoxidation in the central nervous system. The autoxidation chemistry of 5,6-DHT has been studied in aqueous solution at pH 7.2. The reaction is initiated by direct oxidation of the indolamine by molecular oxygen with resultant formation of the corresponding o-quinone 1 and H2O2. A rapid nucleophilic attack by 5,6-DHT on 1 leads to 2,7'-bis(5,6-dihydroxytryptamine) (6) which is more rapidly autoxidized than 5,6-DHT to give the corresponding diquinone 7 along with 2 mol of H2O2. The accumulation of 6 in the reaction solution during the autoxidation of 5,6-DHT despite its more rapid autoxidation indicates that diquinone 7 chemically oxidizes 5,6-DHT (2 mol) to quinone 1 so that an autocatalytic cycle is established. The H2O2 formed as a byproduct of these autoxidation reactions can undergo Fenton chemistry catalyzed by trace transition metal ion contaminants with resultant formation of the hydroxyl radical, HO., which directly oxidizes 5,6-DHT to a radical intermediate (9a/9b). This radical is directly attacked by O2 to yield quinone 1 and superoxide radical anion, O2.-, which further facilitates Fenton chemistry by reducing, inter alia, Fe3+ to Fe2+. A minor side reaction of 1 with water leads to formation of at least two trihydroxytryptamines. Diquinone 7 ultimately reacts with 6, 5,6-DHT, and perhaps trihydroxytryptamines, leading via a sequence of coupling and oxidation reactions to a black indolic melanin polymer. Enzymes such as tyrosinase, ceruloplasmin, and peroxidase and rat brain mitochondria catalyze the oxidation of 5,6-DHT to form dimer 7 and, ultimately, indolic melanin. The role of the autoxidation and the enzyme-mediated and mitochondria-promoted oxidations of 5,6-DHT in expressing the neurodegenerative properties of the indolamine are discussed.

Nitrosothiol formation and protection against Fenton chemistry by nitric oxide-induced dinitrosyliron complex formation from anoxia-initiated cellular chelatable iron increase.

PubMed

Li, Qian; Li, Chuanyu; Mahtani, Harry K; Du, Jian; Patel, Aashka R; Lancaster, Jack R

2014-07-18

Dinitrosyliron complexes (DNIC) have been found in a variety of pathological settings associated with (•)NO. However, the iron source of cellular DNIC is unknown. Previous studies on this question using prolonged (•)NO exposure could be misleading due to the movement of intracellular iron among different sources. We here report that brief (•)NO exposure results in only barely detectable DNIC, but levels increase dramatically after 1-2 h of anoxia. This increase is similar quantitatively and temporally with increases in the chelatable iron, and brief (•)NO treatment prevents detection of this anoxia-induced increased chelatable iron by deferoxamine. DNIC formation is so rapid that it is limited by the availability of (•)NO and chelatable iron. We utilize this ability to selectively manipulate cellular chelatable iron levels and provide evidence for two cellular functions of endogenous DNIC formation, protection against anoxia-induced reactive oxygen chemistry from the Fenton reaction and formation by transnitrosation of protein nitrosothiols (RSNO). The levels of RSNO under these high chelatable iron levels are comparable with DNIC levels and suggest that under these conditions, both DNIC and RSNO are the most abundant cellular adducts of (•)NO. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Nitrosothiol Formation and Protection against Fenton Chemistry by Nitric Oxide-induced Dinitrosyliron Complex Formation from Anoxia-initiated Cellular Chelatable Iron Increase*

PubMed Central

Li, Qian; Li, Chuanyu; Mahtani, Harry K.; Du, Jian; Patel, Aashka R.; Lancaster, Jack R.

2014-01-01

Dinitrosyliron complexes (DNIC) have been found in a variety of pathological settings associated with •NO. However, the iron source of cellular DNIC is unknown. Previous studies on this question using prolonged •NO exposure could be misleading due to the movement of intracellular iron among different sources. We here report that brief •NO exposure results in only barely detectable DNIC, but levels increase dramatically after 1–2 h of anoxia. This increase is similar quantitatively and temporally with increases in the chelatable iron, and brief •NO treatment prevents detection of this anoxia-induced increased chelatable iron by deferoxamine. DNIC formation is so rapid that it is limited by the availability of •NO and chelatable iron. We utilize this ability to selectively manipulate cellular chelatable iron levels and provide evidence for two cellular functions of endogenous DNIC formation, protection against anoxia-induced reactive oxygen chemistry from the Fenton reaction and formation by transnitrosation of protein nitrosothiols (RSNO). The levels of RSNO under these high chelatable iron levels are comparable with DNIC levels and suggest that under these conditions, both DNIC and RSNO are the most abundant cellular adducts of •NO. PMID:24891512

Application of solar photo-Fenton for benzophenone-type UV filters removal.

PubMed

Zúñiga-Benítez, Henry; Peñuela, Gustavo A

2018-07-01

Benzophenones (BPs) family is one of the most frequently used groups of UV-filters. However, it has been reported by different authors that this kind of chemical compounds could be associated with some endocrine disrupting activity, genotoxicity and reproductive toxicity. In addition, different studies have evidenced the presence of BPs in several environmental matrices, indicating that conventional technologies of water treatment are not able to remove them, which generates the necessity of evaluating new alternatives of remediation. In this way, the main objective of this paper was to consider the potential removal of the benzophenone-type compounds, Benzophenone-1 and Benzophenone-2 in aqueous solutions using photo-Fenton under simulated sunlight radiation. Effects of different operational parameters, including H 2 O 2 and Fe 2+ initial concentrations, on pollutants elimination were assessed, and conditions that allow to get higher degradation rates were established. In general, results indicated that evaluated photo-catalytic system is able to remove completely the studied benzophenones, and to increase the samples biodegradability after a notable reduction of the organic carbon present in the solutions. Additionally, the identification of some of the reaction byproducts showed that hydroxylation of the substrates molecules is one of the main stages that conduct to its elimination under the evaluated experimental conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessment of iron chelates efficiency for photo-Fenton at neutral pH.

PubMed

De Luca, Antonella; Dantas, Renato F; Esplugas, Santiago

2014-09-15

In this study, homogeneous photo-Fenton like at neutral pH was applied to remove sulfamethoxazole from water. The process was performed using different chelating agents in order to solubilize iron in a neutral water solution. The chelating agents tested were: ethylenediaminetetraacetic acid (EDTA); nitrilotriacetic acid (NTA); oxalic acid (OA) and tartaric acid (TA). The iron leaching was monitored over reaction time to evaluate the chelates stability and their resistance to HO· and UV-A radiation. Chelates of EDTA and NTA presented more stability than OA and TA, which also confirmed their higher efficiency. Total Organic Carbon (TOC) analyses were also performed to evaluate the contribution in terms of solution contamination related to the use of chelating agents. The better properties of biodegradability in respect of EDTA combined with better efficiency in terms of microcontaminant removal and the smallest TOC contribution indicate that NTA could represent a useful option to perform photo-Fenton processes at neutral pH. Copyright © 2014 Elsevier Ltd. All rights reserved.

Conditioning of sewage sludge by Fenton's reagent combined with skeleton builders.

PubMed

Liu, Huan; Yang, Jiakuan; Shi, Yafei; Li, Ye; He, Shu; Yang, Changzhu; Yao, Hong

2012-06-01

Physical conditioners, often known as skeleton builders, are commonly used to improve the dewaterability of sewage sludge. This study evaluated a novel joint usage of Fenton's reagent and skeleton builders, referred to as the F-S inorganic composite conditioner, focusing on their efficacies and the optimization of the major operational parameters. The results demonstrate that the F-S composite conditioner for conditioning sewage sludge is a viable alternative to conventional organic polymers, especially when ordinary Portland cement (OPC) and lime are used as the skeleton builders. Experimental investigations confirmed that Fenton reaction required sufficient time (80 min in this study) to degrade organics in the sludge. The optimal condition of this process was at pH=5, Fe(2+)=40 mg g(-1) (dry solids), H(2)O(2)=32 mg g(-1), OPC=300 mg g(-1) and lime=400 mg g(-1), in which the specific resistance to filtration reduction efficiency of 95% was achieved. Copyright © 2012 Elsevier Ltd. All rights reserved.

microcrystals as an efficient heterogeneous Fenton-like catalyst in degradation of rhodamine 6G

NASA Astrophysics Data System (ADS)

Li, Zhan Jun; Ali, Ghafar; Kim, Hyun Jin; Yoo, Seong Ho; Cho, Sung Oh

2014-05-01

We present a novel heterogeneous Fenton-like catalyst of LiFePO4 (LFP). LFP has been widely used as an electrode material of a lithium ion battery, but we observed that commercial LFP (LFP-C) could act as a good Fenton-like catalyst to decompose rhodamine 6G. The catalytic activity of LFP-C microparticles was much higher than a popular catalyst, magnetite nanoparticles. Furthermore, we found that the catalytic activity of LFP-C could be further increased by increasing the specific surface area. The reaction rate constant of the hydrothermally synthesized LFP microcrystals (LFP-H) is at least 18 times higher than that of magnetite nanoparticles even though the particle size of LFP is far larger than magnetite nanoparticles. The LFP catalysts also exhibited a good recycling behavior and high stability under an oxidizing environment. The effects of the experimental parameters such as the concentration of the catalysts, pH, and the concentration of hydrogen peroxide on the catalytic activity of LFP were also analyzed.

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

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.

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.

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.

Municipal solid waste landfill leachate treatment by fenton, photo-fenton and fenton-like processes: Effect of some variables

PubMed Central

2012-01-01

Advanced oxidation processes like Fenton and photo-Fenton have been effectively applied to oxidize the persistent organic compounds in solid waste leachate and convert them to unharmful materials and products. However, there are limited data about application of Fenton-like process in leachate treatment. Therefore, this study was designed with the objective of treating municipal landfill leachate by Fenton, Fenton-like and photo–Fenton processes to determine the effect of different variables, by setting up a pilot system. The used leachate was collected from a municipal unsanitary landfill in Qaem-Shahr in the north of Iran. Fenton and Fenton-like processes were conducted by Jar-test method. Photo-Fenton process was performed in a glass photo-reactor. In all processes, H2O2 was used as the oxidant. FeSO4.7H2O and FeCl3.6H2O were used as reagents. All parameters were measured based on standard methods. The results showed that the optimum concentration of H2O2 was equal to 5 g/L for the Fenton-like process and 3 g/L for the Fenton and photo-Fenton processes. The optimum ratio of H2O2: Fe+2/Fe+3 were equal to 8:1 in all processes. At optimum conditions, the amount of COD removal was 69.6%, 65.9% and 83.2% in Fenton, Fenton-like and photo–Fenton processes, respectively. In addition, optimum pH were 3, 5 and 3 and the optimum contact time were 150, 90 and 120 minutes, for Fenton, Fenton-like and photo–Fenton processes, respectively. After all processes, the biodegradability (BOD5/COD ratio) of the treated leachate was increased compared to that of the raw leachate and the highest increase in BOD5/COD ratio was observed in the photo-Fenton process. The efficiency of the Fenton-like process was overally less than Fenton and photo-Fenton processes, meanwhile the Fenton-like process was at higher pH and did not show problems. PMID:23369204

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.

Coupling between high-frequency ultrasound and solar photo-Fenton at pilot scale for the treatment of organic contaminants: an initial approach.

PubMed

Papoutsakis, Stefanos; Miralles-Cuevas, Sara; Gondrexon, Nicolas; Baup, Stéphane; Malato, Sixto; Pulgarin, César

2015-01-01

This study aims to evaluate the performance of a novel pilot-scale coupled system consisting of a high frequency ultrasonic reactor (400kHz) and a compound parabolic collector (CPC). The benefits of the concurrent application of ultrasound and the photo-Fenton process were studied in regard to the degradation behavior of a series of organic pollutants. Three compounds (phenol, bisphenol A and diuron) with different physicochemical properties have been chosen in order to identify possible synergistic effects and to obtain a better estimate of the general feasibility of such a system at field scale (10L). Bisphenol A and diuron were specifically chosen due to their high hydrophobicity, and thus their assumed higher affinity towards the cavitation bubble. Experiments were conducted under ultrasonic, photo-Fenton and combined treatments. Enhanced degradation kinetics were observed during the coupled treatment and synergy factors clearly in excess of 1 have been calculated for phenol as well as for saturated solutions of bisphenol A and diuron. Although the relatively high cost of ultrasound compared to photo-Fenton still presents a significant challenge towards mainstream industrial application, the observed behavior suggests that its prudent use has the potential to significantly benefit the photo-Fenton process, via the decrease of both treatment time and H2O2 consumption. Copyright © 2014 Elsevier B.V. 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.

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.

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.

Hydroxyl radicals from secondary organic aerosol decomposition in water

NASA Astrophysics Data System (ADS)

Tong, H.; Arangio, A. M.; Lakey, P. S. J.; Berkemeier, T.; Liu, F.; Kampf, C. J.; Pöschl, U.; Shiraiwa, M.

2015-11-01

We found that ambient and laboratory-generated secondary organic aerosols (SOA) form substantial amounts of OH radicals upon interaction with liquid water, which can be explained by the decomposition of organic hydroperoxides. The molar OH yield from SOA formed by ozonolysis of terpenes (α-pinene, β-pinene, limonene) is ~ 0.1 % upon extraction with pure water and increases to ~ 1.5 % in the presence of Fe2+ ions due to Fenton-like reactions. Our findings imply that the chemical reactivity and aging of SOA particles is strongly enhanced upon interaction with water and iron. In cloud droplets under dark conditions, SOA decomposition can compete with the classical H2O2 Fenton reaction as the source of OH radicals. Also in the human respiratory tract, the inhalation and deposition of SOA particles may lead to a substantial release of OH radicals, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols.

Hydroxyl radicals from secondary organic aerosol decomposition in water

NASA Astrophysics Data System (ADS)

Tong, Haijie; Arangio, Andrea M.; Lakey, Pascale S. J.; Berkemeier, Thomas; Liu, Fobang; Kampf, Christopher. J.; Pöschl, Ulrich; Shiraiwa, Manabu

2016-04-01

We found that ambient and laboratory-generated secondary organic aerosols (SOA) form substantial amounts of OH radicals upon interaction with liquid water, which can be explained by the decomposition of organic hydroperoxides. The molar OH yield from SOA formed by ozonolysis of terpenes (α-pinene, β-pinene, and limonene) is ~ 0.1% upon extraction with pure water, and which increases to ~ 1.5% in the presence of iron ions due to Fenton-like reactions. Our findings imply that the chemical reactivity and aging of SOA particles is strongly enhanced upon interaction with water and iron. In cloud droplets under dark conditions, SOA decomposition can compete with the classical hydrogen peroxide Fenton reaction as the source of OH radicals. Also in the human respiratory tract, the inhalation and deposition of SOA particles may lead to a substantial release of OH radicals, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols.

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.

An Experimental Model to Study the Impact of Lipid Oxidation on Contact Lens Deposition In Vitro.

PubMed

Schuett, Burkhardt S; Millar, Thomas J

2017-09-01

This study was to establish a controlled in vitro test system to study the effect of lipid oxidation on lipid deposition on contact lenses. Fatty acids with varying degree of unsaturation were oxidized using the Fenton reaction. The degree of lipid oxidation and the lipid moieties formed during the oxidation were identified and estimated by various lipid staining techniques following separation with thin-layer chromatography, and by measuring thiobarbituric acid reactive substances or peroxides in solution. Two different silicone hydrogel-based contact lenses (Balafilcon A and Senofilcon A) were incubated with fatty acids laced with radioactive tracer oxidized to varying degrees, and the amount of lipid deposition was measured using unoxidized lipid samples as controls. The Fenton reaction together with the analytical methods to analyze the lipid oxidation can be used to control oxidation of lipids to a desired amount. In general, saturated fatty acids are not oxidized, the monounsaturated oleic acid produced peroxides while poly-unsaturated lipids initially produced peroxides and then fragmented into reactive aldehydes. Incubation with mildly oxidized lipids (most likely lipid peroxides) resulted in increased lipid deposition on Balafilcon A lenses compared to unoxidized lipids, but this was not observed for Senofilcon A lenses. Further oxidation of the lipids (carbon chain breakup) on the other hand resulted in diminished lipid deposition for both contact lens types. This study provides a method for inducing and controlling lipid oxidation so that the effect of lipid oxidation on contact lens binding can be compared. It could be shown that the degree of lipid oxidation has different effects on the lipid deposition on different contact lens types.

Changes of turbidity during the phenol oxidation by photo-Fenton treatment.

PubMed

Villota, Natalia; Camarero, Luis M; Lomas, Jose M; Perez, Jonatan

2014-11-01

Turbidity presented by phenol solutions oxidized with Fenton reagent shows the tendency of a first order intermediate kinetics. Thus, turbidity can be considered a representative parameter of the presence of intermediate oxidation species, which are generated along the decomposition of toxic and reluctant contaminants, such as phenol. Moreover, that parameter presents a linear dependence with the catalyst dosage, but is also determined by the initial contaminant load. When analyzing the oxidation mechanism of phenol, it is found that the maximum turbidity occurs when the treatment is carried out at oxidant to phenol molar ratios R = 4.0. These oxidation conditions correspond to the presence of a reaction mixture mainly composed of dihydroxylated rings, precursors of the muconic acid formation. The oxidation via "para" comprises the formation reactions of charge transfer complexes (quinhydrone), between the para-dihydroxylated intermediates (hydroquinone) and the para-substituted quinones (p-benzoquinone), which are quite unstable and reactive species, quickly decomposed into hydroxyhydroquinones. Working with oxidant ratios up to R = 6.0, the maximum observed value of turbidity in the oxidized solutions is kept almost constant. It is found that, in these conditions, the pyrogallol formation is maximal, what is generated through the degradation of ortho-species (catechol and ortho-benzoquinone) and meta-substituted (resorcinol). Operating with ratios over R = 6.0, these intermediates are decomposed into biodegradable acids, generating lower turbidity in the solution. Then, the residual turbidity is a function of the molar ratio of the ferrous ions vs. moles of oxidant utilized in the essays, that lets to estimate the stoichiometric dosage of catalyst as 20 mg/L at pH = 3.0, whereas operating in stoichiometric conditions, R = 14.0, the residual turbidity of water results almost null.

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.

Magnetically separable maghemite/montmorillonite composite as an efficient heterogeneous Fenton-like catalyst for phenol degradation.

PubMed

Jin, Mingjie; Long, Mingce; Su, Hanrui; Pan, Yue; Zhang, Qiuzhuo; Wang, Juan; Zhou, Baoxue; Zhang, Yanwu

2017-01-01

To develop highly efficient and conveniently separable iron containing catalysts is crucial to remove recalcitrant organic pollutants in wastewater through a heterogeneous Fenton-like reaction. A maghemite/montmorillonite composite was synthesized by a coprecipitation and calcination method. The physiochemical properties of catalysts were characterized by XRD, TEM, nitrogen physisorption, thermogravimetric analysis/differential scanning calorimetry (TG/DSC), zeta potential, and magnetite susceptibility measurements. The influence of calcination temperatures and reaction parameters was investigated. The calcined composites retain magnetism because the presence of montmorillonite inhibited the growth of γ-Fe 2 O 3 nanoparticles, as well as their phase transition. The catalytic activities for phenol degradation were significantly enhanced by calcinations, which strengthen the interaction between iron oxides and aluminosilicate framework and result in more negatively charged surface. The composite (73 m 2 /g) calcined at 350 °C had the highest catalytic activities, with more than 99 % phenol reduction after only 35 min reaction at pH 3.6. Simultaneously, this catalyst exhibited high stability, low iron leaching, and magnetically separable ability for consecutive usage, making it promising for the removal of recalcitrant organic pollutants in wastewater.

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.

Study of the degradation performance (TOC, BOD, and toxicity) of bisphenol A by the photo-Fenton process.

PubMed

Pérez-Moya, M; Kaisto, T; Navarro, M; Del Valle, L J

2017-03-01

Degradation of bisphenol A (BPA, 0.5 L, 30 mg L -1 ) was studied by photo-Fenton treatment, while Fenton reagents were variables. The efficiency of the degradation process was evaluated by the reduction of total organic carbon (TOC), the biochemical oxygen demand (BOD), and toxicity. For toxicity analysis, bacterial methods were found infeasible, but the in vitro assay of VERO cells culture was successfully applied. Experiments according to a 2 2 design of experiments (DOE) with star points and three center points for statistical validity allowed selecting those process conditions (Fe(II) and H 2 O 2 load) that maximized the process performance. Photo-Fenton process effectively eliminated BPA and partly degraded its by-products (residual TOC <15 %) under substoichiometric H 2 O 2 dose (100.62 mg L -1 ) and at least 4 mg L -1 Fe(II), after a 90-min treatment. All treated samples were at least partially biodegradable. The cytotoxic concentration (LD 50 ) of BPA for VERO cells was 7 mg L -1 . With small H 2 O 2 amount (15.24 mg L -1 ), only low BPA mineralization (TOC = 92 %) was attained. Toxicity was also detected to 50 % of cellular mortality even at long reaction times. However, 40.25 mg L -1 of H 2 O 2 decreased residual TOC to 70 % while cell mortality decreased down to 25 %. With more H 2 O 2 , the residual TOC decreased down to 15 % but cell mortality remained within the 20-25 % level. Photo-Fenton increased the biodegradability and reduced the toxicity of the studied sample.

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.

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.

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.

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...

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%).

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.

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.

Organics, sulfates and ammonia removal from acrylic fiber manufacturing wastewater using a combined Fenton-UASB (2 phase)-SBR system.

PubMed

Li, Jin; Luan, Zhaokun; Yu, Lian; Ji, Zhongguang

2011-11-01

A combined Fenton-UASB (2 phase)-SBR system was employed to treat acrylic fiber manufacturing wastewater. The Chemical Oxygen Demand (COD) removal and effluent Biochemical Oxygen Demand (BOD) to COD were 65.5% and 0.529%, respectively, with the optimal Fenton conditions: ferrous was 300 mg/L; hydrogen peroxide was 500 mg/L; pH was 3.0; reaction time was 2.0 h. In two-phase UASB reactor, mesophilic operation (35±0.5 °C) was performed with hydraulic retention time (HRT) varied between 28 and 40 h. The results showed that with the HRT not less than 38 h, COD and sulfate removal were 65% and 75%, respectively. The greatest sizes of granule formed in the sulfate-reducing and methane-producing phases were 5 and 2 mm, respectively. Sulfate-reducing bacteria (SRB) accounted for 35% in the sulfate-reducing phase while methane-producing archaea (MPA) accounted for 72% in the methane-producing phase. During the SBR process, shortcut nitrification was achieved by temperature control of 30 °C. Copyright © 2011 Elsevier Ltd. All rights reserved.

LiFePO4 microcrystals as an efficient heterogeneous Fenton-like catalyst in degradation of rhodamine 6G.

PubMed

Li, Zhan Jun; Ali, Ghafar; Kim, Hyun Jin; Yoo, Seong Ho; Cho, Sung Oh

2014-01-01

We present a novel heterogeneous Fenton-like catalyst of LiFePO4 (LFP). LFP has been widely used as an electrode material of a lithium ion battery, but we observed that commercial LFP (LFP-C) could act as a good Fenton-like catalyst to decompose rhodamine 6G. The catalytic activity of LFP-C microparticles was much higher than a popular catalyst, magnetite nanoparticles. Furthermore, we found that the catalytic activity of LFP-C could be further increased by increasing the specific surface area. The reaction rate constant of the hydrothermally synthesized LFP microcrystals (LFP-H) is at least 18 times higher than that of magnetite nanoparticles even though the particle size of LFP is far larger than magnetite nanoparticles. The LFP catalysts also exhibited a good recycling behavior and high stability under an oxidizing environment. The effects of the experimental parameters such as the concentration of the catalysts, pH, and the concentration of hydrogen peroxide on the catalytic activity of LFP were also analyzed.

Solar photochemical treatment of winery wastewater in a CPC reactor.

PubMed

Lucas, Marco S; Mosteo, Rosa; Maldonado, Manuel I; Malato, Sixto; Peres, José A

2009-12-09

Degradation of simulated winery wastewater was studied in a pilot-scale compound parabolic collector (CPC) solar reactor. Total organic carbon (TOC) reduction by heterogeneous photocatalysis (TiO(2)) and homogeneous photocatalysis with photo-Fenton was observed. The influence of TiO(2) concentration (200 or 500 mg/L) and also of combining TiO(2) with H(2)O(2) or Na(2)S(2)O(8) on heterogeneous photocatalysis was evaluated. Heterogeneous photocatalysis with TiO(2), TiO(2)/H(2)O(2) and TiO(2)/S(2)O(8)(2-) is revealed to be inefficient in removing TOC, originating TOC degradation of 10%, 11% and 25%, respectively, at best. However, photo-Fenton experiments led to 46% TOC degradation in simulated wastewater prepared with diluted wine (WV) and 93% in wastewater prepared with diluted grape juice (WG), and if ethanol is previously eliminated from mixed wine and grape juice wastewater (WW) by air stripping, it removes 96% of TOC. Furthermore, toxicity decreases during the photo-Fenton reaction very significantly from 48% to 28%. At the same time, total polyphenols decrease 92%, improving wastewater biodegradability.

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.

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.

Cyclodextrin-Enhanced In Situ Removal of Organic Contaminants from Groundwater at Department of Defense Sites

DTIC Science & Technology

2004-05-01

Advantage Nontoxic to humans and resident microbial populations Cyclodextrins are widely used in pharmaceuticals, food processing, and cosmetics ...dechlorination of tetrachloroethene by the Fenton reaction. Environ. Sci. Technol., 17 (9): 1689-1694. 25. Yin, Y., Allen, H.E., 1999: In situ chemical

Mineralization of humic acids (HAs) by a solar photo-Fenton reaction mediated by ferrioxalate complexes: commercial HAs vs extracted from leachates.

PubMed

Santos, Ana P F; Souza, Bianca M; Silva, Tânia F C V; Cavalcante, Rodrigo P; Oliveira, Silvio C; Machulek, Amílcar; Boaventura, Rui A R; Vilar, Vítor J P

2018-03-15

The mineralization of bio-recalcitrant humic acids (HAs) by a solar photo-Fenton (SPF) process was investigated in aqueous system, in order to understand its abatement in real high-HA content matrices, such as sanitary landfill leachates. SPF reactions were performed in tubular photoreactors with CPCs at lab-scale (simulated solar light) and pilot-scale (natural sunlight). Considering the experimental conditions selected for this work, the formation of insoluble HA-Fe 3+ complexes was observed. Thus, to avoid HA precipitation, oxalic acid (Ox) was added, since Fe 3+ -Ox complexes present a higher stability constant. The effect of different process variables on the performance of SPF reaction mediated by ferrioxalate complexes (SPFF) was assessed with excess of H 2 O 2 (50-250 mg L -1 ), at lab-scale: (i) pH (2.8-4.0); (ii) initial iron concentration (20-60 mg Fe 3+ L -1 ); (iii) iron-oxalate molar ratio (Fe 3+ -Ox of 1:3 and 1:6); (iv) temperature (20-40 °C); (v) UV irradiance (21-58 W UV  m -2 ); and (vi) commercial-HA concentration (50-200 mg C L -1 ). At the best lab conditions (40 mg Fe 3+ L -1 , pH 2.8, 30 °C, 1.6 Fe 3+ -Ox molar ratio, 41 W UV m -2 ), commercial HAs' mineralization profile was also compared with HAs extracted from a sanitary landfill leachate, achieving 88 and 91% of dissolved organic carbon removal, respectively, after 3-h irradiation (8.7 kJ UV  L -1 ). Both reactions followed the same trend, although a 2.1-fold increase in the reaction rate was observed for the leachate-HA experiment, due to its lower humification degree. At pilot-scale, under natural sunlight, 95% HA mineralization was obtained, consuming 42 mM of H 2 O 2 and 5.9 kJ UV  L -1 of accumulated UV energy. However, a pre-oxidation during 2.8 kJ UV  L -1 (12 mM H 2 O 2 ) was enough to obtain a biodegradability index of 89%, showing the strong feasibility to couple the SPFF process to a downstream biological oxidation, with low chemicals and energetic demands. Graphical abstract ᅟ.

HPLC-MS degradation study of E10 Sunset Yellow FCF in a commercial beverage.

PubMed

Gosetti, Fabio; Gianotti, Valentina; Polati, Stefano; Gennaro, Maria Carla

2005-10-07

Experimental evidence has shown that a beverage containing Sunset Yellow FCF (labelled as E110 in the European Union), when exposed to natural conditions of summer temperature and sunlight, losses its colour. To possibly identify the degradation pathway and collect information on the potential toxicity of the uncoloured species formed, different degradation conditions, under both oxidising and reducing environments, were simulated in laboratory. Experiments were carried out under the following conditions: (i) thermally induced degradation, (ii) visible photo induced degradation, (iii) UV-photo induced conditions in oxidising environment (addition of hydrogen peroxide, Fenton reaction) and (iv) UV-photo induced conditions in reducing environment (addition of sulphide and ascorbic acid, addition of ascorbic acid in the absence and in the presence of saccharose). Decolourisation process was observed in oxidant conditions when applying the Fenton reaction but the reaction was too quick to be progressively followed. On the other hand, it was also possible to study the degradation reaction observed in reducing conditions in the presence of ascorbic acid. The HPLC-MS results gave evidence for the cleavage of the double bond and the protonation of the azo groups. The loss of colour is therefore not due to a mineralization process but to the formation of a dimeric form of 5-amino-6-hydroxy-2-naphthalene sulfonate and, likely, of p-amino-benzensulfonate.

Simultaneous removal of nitrate, hydrogen peroxide and phosphate in semiconductor acidic wastewater by zero-valent iron.

PubMed

Yoshino, Hiroyuki; Tokumura, Masahiro; Kawase, Yoshinori

2014-01-01

The zero-valent iron (ZVI) wastewater treatment has been applied to simultaneous removal of nitrate, hydrogen peroxide and phosphate in semiconductor acidic wastewaters. The simultaneous removal occurs by the reactions performed due to the sequential transformation of ZVI under the acidic condition. Fortunately the solution pH of semiconductor acidic wastewaters is low which is effective for the sequential transformation of ZVI. Firstly the reduction of nitrate is taken place by electrons generated by the corrosion of ZVI under acidic conditions. Secondly the ferrous ion generated by the corrosion of ZVI reacts with hydrogen peroxide and generates ·OH radical (Fenton reaction). The Fenton reaction consists of the degradation of hydrogen peroxide and the generation of ferric ion. Finally phosphate precipitates out with iron ions. In the simultaneous removal process, 1.6 mM nitrate, 9.0 mM hydrogen peroxide and 1.0 mM phosphate were completely removed by ZVI within 100, 15 and 15 min, respectively. The synergy among the reactions for the removal of nitrate, hydrogen peroxide and phosphate was found. In the individual pollutant removal experiment, the removal of phosphate by ZVI was limited to 80% after 300 min. Its removal rate was considerably improved in the presence of hydrogen peroxide and the complete removal of phosphate was achieved after 15 min.

Application of solar AOPs and ozonation for elimination of micropollutants in municipal wastewater treatment plant effluents.

PubMed

Prieto-Rodríguez, L; Oller, I; Klamerth, N; Agüera, A; Rodríguez, E M; Malato, S

2013-03-15

Conventional municipal wastewater treatment plants are not able to entirely degrade some organic pollutants that end up in the environment. Within this group of contaminants, Emerging Contaminants are mostly unregulated compounds that may be candidates for future regulation. In this work, different advanced technologies: solar heterogeneous photocatalysis with TiO(2), solar photo-Fenton and ozonation, are studied as tertiary treatments for the remediation of micropollutants present in real municipal wastewater treatment plants effluents at pilot plant scale. Contaminants elimination was followed by Liquid Chromatography/Quadrupole ion trap Mass Spectrometry analysis after a pre-concentration 100:1 by automatic solid phase extraction. 66 target micropollutants were identified and quantified. 16 of those contaminants at initial concentrations over 1000 ng L(-1), made up over 88% of the initial total effluent pollutant load. The order of micropollutants elimination efficiency under the experimental conditions evaluated was solar photo-Fenton > ozonation > solar heterogeneous photocatalysis with TiO(2). Toxicity analyses by Vibrio fischeri and respirometric tests showed no significant changes in the effluent toxicity after the three tertiary treatments application. Solar photo-Fenton and ozonation treatments were also compared from an economical point of view. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

Paracetamol degradation intermediates and toxicity during photo-Fenton treatment using different iron species.

PubMed

Trovó, Alam G; Pupo Nogueira, Raquel F; Agüera, Ana; Fernandez-Alba, Amadeo R; Malato, Sixto

2012-10-15

The photo-Fenton degradation of paracetamol (PCT) was evaluated using FeSO(4) and the iron complex potassium ferrioxalate (FeOx) as iron source under simulated solar light. The efficiency of the degradation process was evaluated considering the decay of PCT and total organic carbon concentration and the generation of carboxylic acids, ammonium and nitrate, expressed as total nitrogen. The results showed that the degradation was favored in the presence of FeSO(4) in relation to FeOx. The higher concentration of hydroxylated intermediates generated in the presence of FeSO(4) in relation to FeOx probably enhanced the reduction of Fe(III) to Fe(II) improving the degradation efficiency. The degradation products were determined using liquid chromatography electrospray time-of-flight mass spectrometry. Although at different concentrations, the same intermediates were generated using either FeSO(4) or FeOx, which were mainly products of hydroxylation reactions and acetamide. The toxicity of the sample for Vibrio fischeri and Daphnia magna decreased from 100% to less than 40% during photo-Fenton treatment in the presence of both iron species, except for D. magna in the presence of FeOx due to the toxicity of oxalate to this organism. The considerable decrease of the sample toxicity during photo-Fenton treatment using FeSO(4) indicates a safe application of the process for the removal of this pharmaceutical. Copyright © 2012 Elsevier Ltd. All rights reserved.

Quick photo-Fenton degradation of phenolic compounds by Cu/Al2O3-MCM-41 under visible light irradiation: small particle size, stabilization of copper, easy reducibility of Cu and visible light active material.

PubMed

Pradhan, Amaresh C; Nanda, Binita; Parida, K M; Das, Mira

2013-01-14

The present study reports the photo-Fenton degradation of phenolic compounds (phenol, 2-chloro-4-nitrophenol and 4-chloro-2-nitrophenol) in aqueous solution using mesoporous Cu/Al(2)O(3)-MCM-41 nanocomposite as a heterogeneous photo-Fenton-like catalyst. The in situ incorporation of mesoporous Al(2)O(3) (MA) into the framework of MCM-41 (sol-gel method) forms Al(2)O(3)-MCM-41 and wetness impregnation of Cu(II) on Al(2)O(3)-MCM-41 generates mesoporous Cu/Al(2)O(3)-MCM-41 composite. The effects of pH and H(2)O(2) concentration on degradation of phenol, 2-chloro-4-nitrophenol and 4-chloro-2-nitrophenol are studied. Kinetics analysis shows that the photocatalytic degradation reaction follows a first-order rate equation. Mesoporous 5 Cu/Al(2)O(3)-MCM-41 is found to be an efficient photo-Fenton-like catalyst for the degradation of phenolic compounds. It shows nearly 100% degradation in 45 min at pH 4. The combined effect of small particle size, stabilization of Cu(2+) on the support Al(2)O(3)-MCM-41, ease reducibility of Cu(2+) and visible light activeness are the key factors for quick degradation of phenolic compounds by Cu/Al(2)O(3)-MCM-41.

Degradation of dichlorvos using hydrodynamic cavitation based treatment strategies.

PubMed

Joshi, Ravi K; Gogate, Parag R

2012-05-01

The degradation of an aqueous solution of dichlorvos, a commonly used pesticide in India, has been systematically investigated using hydrodynamic cavitation reactor. All the experiments have been carried out using a 20 ppm solution of commercially available dichlorvos. The effect of important operating parameters such as inlet pressure (over a range 3-6 bar), temperature (31 °C, 36 °C and 39 °C) and pH (natural pH = 5.7 and acidic pH = 3) on the extent of degradation has been investigated initially. It has been observed that an optimum value of pressure gives maximum degradation whereas low temperature and pH of 3 are favorable. Intensification studies have been carried out using different additives such as hydrogen peroxide, carbon tetrachloride, and Fenton's reagent. Use of hydrogen peroxide and carbon tetrachloride resulted in the enhancement of the extent of degradation at optimized conditions but significant enhancement was obtained with the combined use of hydrodynamic cavitation and Fenton's chemistry. The maximum extent of degradation as obtained by using a combination of hydrodynamic cavitation and Fenton's chemistry was 91.5% in 1h of treatment time. The present work has conclusively established that hydrodynamic cavitation in combination with Fenton's chemistry can be effectively used for the degradation of dichlorvos. Copyright © 2011 Elsevier B.V. All rights reserved.

Degradation of fifteen emerging contaminants at microg L(-1) initial concentrations by mild solar photo-Fenton in MWTP effluents.

PubMed

Klamerth, N; Rizzo, L; Malato, S; Maldonado, Manuel I; Agüera, A; Fernández-Alba, A R

2010-01-01

The degradation of 15 emerging contaminants (ECs) at low concentrations in simulated and real effluent of municipal wastewater treatment plant with photo-Fenton at unchanged pH and Fe=5 mg L(-1) in a pilot-scale solar CPC reactor was studied. The degradation of those 15 compounds (Acetaminophen, Antipyrine, Atrazine, Caffeine, Carbamazepine, Diclofenac, Flumequine, Hydroxybiphenyl, Ibuprofen, Isoproturon, Ketorolac, Ofloxacin, Progesterone, Sulfamethoxazole and Triclosan), each with an initial concentration of 100 microg L(-1), was found to depend on the presence of CO(3)(2-) and HCO(3)(-) (hydroxyl radicals scavengers) and on the type of water (simulated water, simulated effluent wastewater and real effluent wastewater), but is relatively independent of pH, the type of acid used for release of hydroxyl radicals scavengers and the initial H(2)O(2) concentration used. Toxicity tests with Vibrio fisheri showed that degradation of the compounds in real effluent wastewater led to toxicity increase. (c) 2009 Elsevier Ltd. All rights reserved.

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.

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

Hydroxyl radicals from secondary organic aerosol decomposition in water

NASA Astrophysics Data System (ADS)

Tong, Haijie; Arangio, Andrea M.; Lakey, Pascale S. J.; Berkemeier, Thomas; Liu, Fobang; Kampf, Christopher J.; Brune, William H.; Pöschl, Ulrich; Shiraiwa, Manabu

2016-02-01

We found that ambient and laboratory-generated secondary organic aerosols (SOA) form substantial amounts of OH radicals upon interaction with liquid water, which can be explained by the decomposition of organic hydroperoxides. The molar OH yield from SOA formed by ozonolysis of terpenes (α-pinene, β-pinene, limonene) is ˜ 0.1 % upon extraction with pure water and increases to ˜ 1.5 % in the presence of Fe2+ ions due to Fenton-like reactions. Upon extraction of SOA samples from OH photooxidation of isoprene, we also detected OH yields of around ˜ 0.1 %, which increases upon addition of Fe2+. Our findings imply that the chemical reactivity and aging of SOA particles is strongly enhanced upon interaction with water and iron. In cloud droplets under dark conditions, SOA decomposition can compete with the classical H2O2 Fenton reaction as the source of OH radicals. Also in the human respiratory tract, the inhalation and deposition of SOA particles may lead to a substantial release of OH radicals, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols.

Controlled Cross-Linking with Glucose Oxidase for the Enhancement of Gelling Potential of Pork Myofibrillar Protein.

PubMed

Wang, Xu; Xiong, Youling L; Sato, Hiroaki; Kumazawa, Yoshiyuki

2016-12-21

Differential oxidative modifications of myofibrillar protein (MP) by hydroxyl radicals generated in an enzymatic system with glucose oxidase (GluOx) in the presence of glucose/FeSO 4 versus a Fenton system (H 2 O 2 /FeSO 4 ) were investigated. Pork MP was modified at 4 °C and pH 6.25 with hydroxyl radicals produced from 1 mg/mL glucose in the presence of 80, 160, or 320 μg/mL GluOx and 10 μM FeSO 4 . Total sulfhydryl content, solubility, cross-linking pattern, and gelation properties of MP were measured. H 2 O 2 production proceeded linearly with the concentration of GluOx and increased with reaction time. GluOx- and H 2 O 2 -dose-dependent protein polymerization, evidenced by faded myosin heavy chain and actin in SDS-PAGE as well as significant decreases in sulfhydryls, coincided with protein solubility loss. Firmer and more elastic MP gels were produced by GluOx than by the Fenton system at comparable H 2 O 2 levels due to an altered radical reaction pathway.

Role of indigenous iron in improving sludge dewaterability through peroxidation

PubMed Central

Zhou, Xu; Jiang, Guangming; Wang, Qilin; Yuan, Zhiguo

2015-01-01

Improvement of sludge dewaterability is important for reducing the total costs for the treatment and disposal of sludge in wastewater treatment plants. In this study, we investigate the use of hydrogen peroxide as an oxidizing reagent for the conditioning of waste activated sludge. Significant improvement to sludge dewaterability was attained after the addition of hydrogen peroxide at 30 mg/g TS and 28 mg/g TS under acidic conditions (pH = 3.0), with the highest reduction of capillary suction time being 68% and 56%, respectively, for sludge containing an iron concentration of 56 mg Fe/g TS and 25 mg Fe/g TS, respectively. The observations were due to Fenton reactions between the iron contained in sludge (indigenous iron) and hydrogen peroxide. For the sludge with an insufficient level of indigenous iron, the addition of ferrous chloride was found to be able to improve the sludge dewaterability. The results firstly indicated that indigenous iron can be utilized similarly as the externally supplied iron salt to improve sludge dewaterability through catalyzing the Fenton reactions. PMID:25559367

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)].

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.

Soil organic matter-hydrogen peroxide dynamics in the treatment of contaminated soils and groundwater using catalyzed H2O2 propagations (modified Fenton's reagent).

PubMed

Bissey, Lauren L; Smith, Jeffrey L; Watts, Richard J

2006-07-01

The interactions between catalyzed H(2)O(2) propagations (CHP-i.e. modified Fenton's reagent) and soil organic matter (SOM) during the treatment of contaminated soils and groundwater was studied in a well-characterized surface soil. The fate of two fractions of SOM, particulate organic matter (POM) and nonparticulate organic matter (NPOM), during CHP reactions was evaluated using concentrations of hydrogen peroxide from 0.5 to 3M catalyzed by soluble iron (III), an iron (III)-ethylenediamine tetraacetic acid (EDTA) chelate, or naturally-occurring soil minerals. The destruction of total SOM in CHP systems was directly proportional to the hydrogen peroxide dosage, and was significantly greater at pH 3 than at neutral pH; furthermore, SOM destruction occurred predominantly in the NPOM fraction. At pH 3, SOM did not affect hydrogen peroxide decomposition rates or hydroxyl radical activity in CHP reactions. However, at neutral pH, increasing the mass of SOM decreased the hydrogen peroxide decomposition rate and increased the rate of hydroxyl radical generation in CHP systems. These results show that, while CHP reactions destroy some of the organic carbon pools, SOM does not have a significant effect on the CHP treatment of soils and groundwater.

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.

Nanostructured catalysts applied to degrade atrazine in aqueous phase by heterogeneous photo-Fenton process.

PubMed

Benzaquén, Tamara B; Barrera, Deicy A; Carraro, Paola M; Sapag, Karim; Alfano, Orlando M; Eimer, Griselda A

2018-06-02

SBA-15 and KIT-6 materials have been synthesized and modified with iron salts by the wet impregnation method with different metal loadings. The different mesostructures obtained were characterized by N 2 adsorption-desorption at 77 K, X-ray diffraction, temperature-programmed reduction, and ultraviolet-visible spectroscopy. These iron-containing mesostructured materials have been successfully tested for the heterogeneous photo-Fenton degradation of aqueous solutions of dangerous herbicides, such as atrazine, using UV-visible light irradiation, at room temperature and close to neutral pH. The results showed that the Fe/SBA-15 (10%) and Fe/KIT-6 (5%) catalysts exhibited the highest activities. However, the Fe/KIT-6 (5%) catalyst with minor Fe loading than Fe/SBA-15 (10%) presented a higher degradation of atrazine (above 98% in a reaction time of 240 min). Therefore, the interconnectivity of the cage-like mesopores had an important influence on the catalytic activity, favoring probably mass-transfer effects. Thus, the high performance of these materials indicates that the heterogeneous via of photo-Fenton process can also be efficiently employed to treat wastewaters containing pollutants such as herbicides, in order to reduce them to simplest and less toxic molecules.

An in vivo ESR spin-trapping study: Free radical generation in rats from formate intoxication— role of the Fenton reaction

PubMed Central

Dikalova, Anna E.; Kadiiska, Maria B.; Mason, Ronald P.

2001-01-01

Electron spin resonance spectroscopy has been used to study free radical generation in rats with acute sodium formate poisoning. The in vivo spin-trapping technique was used with α-(4-pyridyl-1-oxide)-N-t-butylnitrone (POBN), which reacts with free radical metabolites to form radical adducts, which were detected in the bile and urine samples from Fischer rats. The use of [13C]-sodium formate and computer simulations of the spectra identified the 12-line spectrum as arising from the POBN/carbon dioxide anion radical adduct. The identification of POBN/⋅CO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{_{2}^{-}}}\\end{equation*}\\end{document} radical adduct provides direct electron spin resonance spectroscopy evidence for the formation of ⋅CO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{_{2}^{-}}}\\end{equation*}\\end{document} radicals during acute intoxication by sodium formate, suggesting a free radical metabolic pathway. To study the mechanism of free radical generation by formate, we tested several known inhibitors. Both allopurinol, an inhibitor of xanthine oxidase, and aminobenzotriazole, a cytochrome P450 inhibitor, decreased free radical formation from formate, which may imply a dependence on hydrogen peroxide. In accord with this hypothesis, the catalase inhibitor 3-aminotriazole caused a significant increase in free radical formation. The iron chelator Desferal decreased the formation of free radicals up to 2-fold. Presumably, iron plays a role in the mechanism of free radical generation by formate via the Fenton reaction. The detection of formate free radical metabolites generated in vivo and the key role of the Fenton reaction in this process may be important for understanding the pathogenesis of both formate and methanol intoxication. PMID:11717423

[Sensing of Cu²⁺ Based on Fenton Reaction and Unmodified Gold Nanoparticles].

PubMed

Xing, Yun-peng; Liu, Chun; Zhou, Xiao-hong; Zhang, Li-pei; Shi, Han-chang

2015-11-01

Heavy metal pollution has received great attentions in recent years. The traditional methods for heavy metal detection rely on the expensive laboratory instruments and need time-consuming preparation steps; therefore, it is urgent to develop quick and highly sensitive new technologies for heavy metal detection. The colorimetric method based on the gold nanoparticles (AuNPs) features with simple operation, high sensitivity and low cost, therefore, enabling it widely concerned and used in the environmental monitoring, food safety and chemical and biological sensing fields. This work developed a simple, rapid and highly sensitive strategy based on the Fenton reaction and unmodified AuNPs for the detection of Cu²⁺ in water samples. The hydroxyl radical ( · OH) generated by the Fenton reaction between the Cu²⁺ and sodium ascorbate (SA) oxidized the single stranded DNA (ssDNA) attached on the AuNPs surface into variable sequence fragments. The cleavage of ssDNA induced the aggregation of AuNPs in a certain salt solution, therefore, resulting in the changes on the absorbance of solution. The assay conditions were optimized to be pH value of 7.9, 11 mg · L⁻¹ ssDNA, 8 mmol · L⁻¹ SA and 70 mmol · L⁻¹ NaCl. Results showed that the absorbance ratio values at the wavelengths of 700 and 525 nm (A₇₀₀/A₅₂₅) were linearly correlated with the Cu²⁺ concentrations. The linear detection range was 0.1-10.0 µmol · L⁻¹ with a detection limit of 24 nmol · L⁻¹ (3σ). Spiked recoveries ranged from 87%-120% in three sorts of water, including drinking water, tap water and lake water, which confirmed that the potentials of the proposed assay for Cu²⁺ detection in reality.

Experimental design applied to photo-Fenton treatment of highly methomyl-concentrated water.

PubMed

Micó, María M; Bacardit, Jordi; Sans, Carme

2010-01-01

This work is focused on the study of the suitability of the photo-Fenton process as a pretreatment for water highly contaminated with a methomyl commercial formulation in Advanced Greenhouses devices. Initial concentrations of reagents and pesticide were evaluated according to a central composite experimental design, with methomyl depletion and biocompatibility of the final effluent as response functions. A triad of optimal operation conditions could be determined, [Met.](0)=50 mg L(-1), [H(2)O(2)](0)=254 mg L(-1) and [Fe(2+)](0)=77 mg L(-1) for the best elimination yield and an acceptable BOD(5)/COD value, and initial concentration of methomyl can be established as the most important parameter for the performance of the treatment due to the limitations that impose on the hydrogen peroxide doses in the presence of the excipients of the commercial formulation.

Solvothermal in situ synthesis of Fe{sub 3}O{sub 4}-multi-walled carbon nanotubes with enhanced heterogeneous Fenton-like activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Jingheng; Wen, Xianghua, E-mail: xhwen@tsinghua.edu.cn; Wang, Qinian

Graphical abstract: After purification, the multi-wall carbon nanotubes (MWCNTs) act as seeds for Fe{sub 3}O{sub 4} nanoparticles heterogeneous nucleation. The Fe{sub 3}O{sub 4} nanoparticles with diameter range of 4.2–10.0 nm synthesized in situ on the MWCNTs under solvothermal condition. The formed nano Fe{sub 3}O{sub 4}-MWCNTs decolorized the Acid Orange II effectively via Fenton-like reaction. Highlights: ► The amount of water tunes size and size distribution of the Fe{sub 3}O{sub 4} nanoparticles (FNs). ► FNs are homogeneously coated on the multi-walled carbon nanotubes (MWCNTs). ► FNs have diameters in the range of 4.2–10.0 nm, average grain size of 7.4 nm. ►more » Fe{sub 3}O{sub 4}-MWCNTs are used as a Fenton-like catalyst to decompose Acid Orange II. ► Fe{sub 3}O{sub 4}-MWCNTs displayed a higher activity than nanometer-size Fe{sub 3}O{sub 4}. -- Abstract: Fe{sub 3}O{sub 4}-multi-walled carbon nanotubes (Fe{sub 3}O{sub 4}-MWCNTs) hybrid materials were synthesized by a solvothermal process using acid treated MWCNTs and iron acetylacetonate in a mixed solution of ethylene glycol and ultrapure water. The materials were characterized using X-ray powder diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The results showed that a small amount of water in the synthesis system played a role in controlling crystal phase formation, size of Fe{sub 3}O{sub 4}, and the homogeneous distribution of the Fe{sub 3}O{sub 4} nanoparticles deposited on the MWCNTs. The Fe{sub 3}O{sub 4} nanoparticles had diameters in the range of 4.2–10.0 nm. They displayed good superparamagnetism at room temperature and their magnetization was influenced by the reaction conditions. They were used as a Fenton-like catalyst to decompose Acid Orange II and displayed a higher activity than nanometer-size Fe{sub 3}O{sub 4}.« less

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.

Reaction mechanism of dicofol removal by cellulase.

PubMed

Wang, Ziyuan; Yang, Ting; Zhai, Zihan; Zhang, Boya; Zhang, Jianbo

2015-10-01

It remains unclear whether dicofol should be defined as a persistent organic pollutant. Its environmental persistence has gained attention. This study focused on its degradation by cellulase. Cellulase was separated using a gel chromatogram, and its degradation activity towards dicofol involved its endoglucanase activity. By analyzing the kinetic parameters of cellulase reacting with mixed substrates, it was shown that cellulase reacted on dicofol and carboxyl methyl cellulose through two different active centers. Thus, the degradation of dicofol was shown to be an oxidative process by cellulase. Next, by comparing the impacts of tert-butyl alcohol (a typical OH free-radical inhibitor) on the removal efficiencies of dicofol under both cellulase and Fenton reagent systems, it was shown that the removal of dicofol was initiated by OH free radicals produced by cellulase. Finally, 4,4'-dichloro-dibenzophenone and chloride were detected using gas chromatography mass spectrometry and ion chromatography analysis, which supported our hypothesis. The reaction mechanism was analyzed and involved an attack by OH free radicals at the orthocarbon of dicofol, resulting in the degradation product 4,4'-dichloro-dibenzophenone. Copyright © 2015. Published by Elsevier B.V.

Fenton-like oxidation of 4-chlorophenol using H2O2 in situ generated by Zn-Fe-CNTs composite.

PubMed

Liu, Yong; Fan, Qing; Liu, Yanlan; Wang, Jianlong

2018-05-15

In this paper, a zinc-iron-carbon nanotubes (Zn-Fe-CNTs) composite was prepared, characterized and used to develop a Fenton-like system of Zn-Fe-CNTs/O 2 for the degradation of 4-chlorophenol (4-CP), in which H 2 O 2 was generated in situ from zinc-carbon galvanic cells and oxygen in aqueous solution was activated by iron attached on the surface of CNTs to produce ·OH radicals for the oxidation of 4-CP. The experimental results showed that the particles of Zn and Fe in Zn-Fe-CNTs composite were adhered to the surface of CNTs, which accelerated the electron transfer process. The BET area of Zn-Fe-CNTs composite was 32.9 m 2 /g. The contents of Zn and Fe (% w) in the composite were 44.7% and 4.2%, respectively. The removal efficiency of 4-CP and TOC in Zn-Fe-CNTs/O 2 system was 90.8% and 52.9%, respectively, with the initial pH of 2.0, O 2 flow rate of 800 mL/min, Zn-Fe-CNTs dosage of 1.0 g/L, 4-CP concentration of 50 mg/L and reaction time of 20 min. Based on the analysis of the degradation intermediate products with LC-MS and IC, a possible degradation pathway of 4-CP in Zn-Fe-CNTs/O 2 system was proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Kinetics of Acid Orange 7 oxidation by using carbon fiber and reticulated vitreous carbon in an electro-Fenton process.

PubMed

Ramírez-Pereda, Blenda; Álvarez-Gallegos, Alberto; Rangel-Peraza, Jesús Gabriel; Bustos-Terrones, Yaneth A

2018-05-01

In this study, a micro-scale parallel plate reactor was built to electrochemically generate hydrogen peroxide (H 2 O 2 ) and to develop the Fenton reaction in situ, for the treatment of toxic organic pollutants. Two types of carbon materials were compared and used as cathodes: unidirectional carbon fiber (CF) and reticulated vitreous carbon (RVC). As anode, a stainless steel mesh was used. The results of H 2 O 2 were experimentally compared by means of electrogeneration process. RVC cathode with dimensions of 2.5 × 1 × 5 cm (170 mA and variable voltage V = 2.0-2.7) and 180 min produced 5.3 mM H 2 O 2 , with an H 2 O 2 production efficiency of 54%. Unidirectional carbon fiber cathode produced 7.5 mM of H 2 O 2 (96% of H 2 O 2 production efficiency) when a voltage of 1.8 V was applied during 180 min to a total area of 480 cm 2 of this material. Acid Orange 7 (AO7) was degraded to a concentration of 0.16 mM during the first 40 min of the process, which represented 95% of the initial concentration. Electrolysis process removed nearly 100% of the AO7 using both cathodes at the end of these experiments (180 min). Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Decolorization of Mordant red 73 azo dye in water using H2O2/UV and photo-Fenton treatment.

PubMed

Elmorsi, Taha M; Riyad, Yasser M; Mohamed, Zeinhom H; Abd El Bary, Hassan M H

2010-02-15

Decolorization of the Mordant red 73 (MR73) azo dye in water was investigated in laboratory-scale experiments using UV/H(2)O(2) and photo-Fenton treatments. Photodegradation experiments were carried out in a stirred batch photoreactor equipped with a low-pressure mercury lamp as UV source at 254 nm. The effect of operating parameters such as pH, [H(2)O(2)](,) [dye] and the presence of inorganic salts (NaNO(3), NaCl and Na(2)CO(3)) were also investigated. The results indicated that complete dye decolorization was obtained in less than 60 min under optimum conditions. Furthermore, results showed that dye degradation was dependent upon pH, [H(2)O(2)] and initial dye concentration. The presence of chloride ion led to large decreases in the photodegradation rate of MR73 while both nitrate and carbonate ions have a slight effect. The photo-Fenton treatment, in the presence of Fe powder as a source of Fe(2+) ions, was highly efficient and resulted in 99% decolorization of the dye in 15 min. Mineralization of MR73 dye was investigated by determining chemical oxygen demand (COD). In a 3h photoperiod "65%" of the dye was mineralized by the H(2)O(2)/UV process, while the photo-Fenton treatment was more efficient producing 85% mineralization over the same 3-h period.

Comparison of Fenton process and adsorption method for treatment of industrial container and drum cleaning industry wastewater.

PubMed

Güneş, Elçin; Çifçi, Deniz İzlen; Çelik, Suna Özden

2018-04-01

The present study aims to explore the characterization of industrial container and drum cleaning (ICDC) industry wastewater and treatment alternatives of this wastewater using Fenton and adsorption processes. Wastewater derived from ICDC industry is usually treated by chemical coagulation and biological treatment in Turkey and then discharged in a centralized wastewater treatment facility. It is required that the wastewater COD is below 1500 mg/L to treat in a centralized wastewater treatment facility. The wastewater samples were characterized for parameters of pH, conductivity, COD, BOD 5 , TSS, NH 3 -N, TN, TOC, TP, Cd, Cr, Cu, Fe, Ni, Pb, Zn, and Hg. Initial COD values were in the range of 11,300-14,200 mg/L. The optimum conditions for Fenton treatment were 35-40 g/L for H 2 O 2 , 2-5 g/L for Fe 2+ , and 13-36 for H 2 O 2 /Fe 2+ molar ratio. The optimum conditions of PAC doses and contact times in adsorption studies were 20-30 g/L and 5-12 h, respectively. Removal efficiencies of characterized parameters for the three samples were compared for both Fenton and adsorption processes under optimum conditions. The results suggest that these wastewaters are suitable for discharge to a centralized wastewater treatment plant.

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.

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.

IRON AND FREE RADICAL OXIDATIONS IN CELL MEMBRANES

PubMed Central

Schafer, Freya Q.; Yue Qian, Steven; Buettner, Garry R.

2013-01-01

Brain tissue being rich in polyunsaturated fatty acids, is very susceptible to lipid peroxidation. Iron is well known to be an important initiator of free radical oxidations. We propose that the principal route to iron-mediated lipid peroxidations is via iron-oxygen complexes rather than the reaction of iron with hydrogen peroxide, the Fenton reaction. To test this hypothesis, we enriched leukemia cells (K-562 and L1210 cells) with docosahexaenoic acid (DHA) as a model for brain tissue, increasing the amount of DHA from approximately 3 mole % to 32 mole %. These cells were then subjected to ferrous iron and dioxygen to initiate lipid peroxidation in the presence or absence of hydrogen peroxide. Lipid-derived radicals were detected using EPR spin trapping with α-(4-pyridyl-1-oxide)-N-t-butylnitrone (POBN). As expected, lipid-derived radical formation increases with increasing cellular lipid unsaturation. Experiments with Desferal demonstrate that iron is required for the formation of lipid radicals from these cells. Addition of iron to DHA-enriched L1210 cells resulted in significant amounts of radical formation; radical formation increased with increasing amount of iron. However, the exposure of cells to hydrogen peroxide before the addition of ferrous iron did not increase cellular radical formation, but actually decreased spin adduct formation. These data suggest that iron-oxygen complexes are the primary route to the initiation of biological free radical oxidations. This model proposes a mechanism to explain how catalytic iron in brain tissue can be so destructive. PMID:10872752

Effect of substituted hydroxyl groups in the changes of solution turbidity in the oxidation of aromatic contaminants.

PubMed

Villota, N; Jm, Lomas; Lm, Camarero

2017-01-01

This paper deals with the changes of turbidity that are generated in aqueous solutions of phenol when they are oxidized by using different Fenton technologies. Results revealed that if the Fenton reaction was promoted with UV light, the turbidity that was generated in the water doubled. Alternatively, the use of ultrasonic waves produced an increase in turbidity which initially proceeded slowly, reaching intensities eight times higher than in the conventional Fenton treatment. As well, the turbidity showed a high dependence on pH. It is therefore essential to control acidity throughout the reaction. The maximum turbidity was generated when operating at pH = 2.0, and it slowly decreased with increasing to a value of pH = 3.0, at which the turbidity was the lowest. This result was a consequence of the presence of ferric ions in solution. At pH values greater than 3.5, the turbidity increased almost linearly until at pH = 5.0 reached its maximum intensity. In this range, ferrous ions may generate an additional contribution of radicals that promote the degradation of the phenol species that produce turbidity. Turbidity was enhanced at ratios R = 4.0 mol H 2 O 2 /mol C 6 H 6 O. This value corresponds to the stoichiometric ratio that leads to the production of turbidity-precursor species. Therefore, muconic acid would be a species that generate high turbidity in solution according to its isomerism. Also, the results revealed that the turbidity is not a parameter to which species contribute additively since interactions may occur among species that would enhance their individual contributions to it. Analyzing the oxidation of phenol degradation intermediates, the results showed that meta-substituted compounds (resorcinol) generate high turbidity in the wastewater. The presence of polar molecules, such as muconic acid, would provide the structural features that are necessary for resorcinol to act as a clip between two carboxylic groups, thus establishing directional hydrogen bonds that would generate an adduct in the 2:2 ratio. In addition, some similarity is observed between the turbidity and the presence of dihydroxybenzoquinone. This molecule has a structure that could establish hydrogen bond links with the carboxylic groups in 1:2 ratio. Such supramolecular structures would possess high molecular weight and robustness that would hinder the passage of light through the water, generating high turbidity.

Effect of calcination temperature of a copper ferrite synthesized by a sol-gel method on its structural characteristics and performance as Fenton catalyst to remove gallic acid from water.

PubMed

López-Ramón, María V; Álvarez, Miguel A; Moreno-Castilla, Carlos; Fontecha-Cámara, María A; Yebra-Rodríguez, África; Bailón-García, Esther

2018-02-01

A copper ferrite synthesized by a sol-gel combustion method was calcined at different temperatures up to 800°C, determining changes in its structural characteristics and magnetic measurements and studying its catalytic performance in gallic acid removal by Fenton reaction. The main objective was to study the effect of the calcination temperature of copper ferrite on its crystalline phase formation and transformation, activity and metal ion leaching. The cubic-to-tetragonal transformation of the spinel occurred via its reaction with the CuO phase, displacing Fe 3+ ions in B (octahedral) sites out of the spinel structure by the following reaction: 2Fe 3+ B +3CuO→Fe 2 O 3 +3Cu 2+ B . The catalysts showed superparamagnetic or substantial superparamagnetic behaviour. At higher calcination temperatures, catalyst activity was lower, and Cu ion leaching was markedly decreased. There was no Fe ion leaching with any catalyst. The as-prepared catalyst showed better catalytic performance than a commercial copper ferrite. Leached Cu ions acted as homogeneous catalysts, and their contribution to the overall removal mechanism was examined. Cu 2 O present in the as-prepared catalysts made only a small contribution to their activity. Finally, the reutilization of various catalysts was studied by performing different catalytic cycles. Copyright © 2017 Elsevier Inc. All rights reserved.

MTBE DEGRADATION USING FENTON'S REAGENT: THE EFFECT OF FERROUS AND FERRIC IRON MIXTURES ON THE EFFICIENCY OF THE OVERALL REACTION

EPA Science Inventory

The gasoline additive MTBE has been extensively used in the U.S. since the late 70's to increase the octane rating in reformulated gasoline, replacing toxic organo-lead compounds. However, its use was boosted during the late 80's, when the study of additional physico-chemical pro...

MTBE DEGRADATION USING FENTON REAGENT: THE EFFECT OF FERROUS AND FERRIC IRON MIXTURES ON THE EFFICIENCY OF THE OVERALL REACTION

EPA Science Inventory

The gasoline additive MTBE has been extensively used in the U.S. since the late 70's to increase the octane rating in reformulated gasoline, replacing toxic organo-lead compounds. However, its use was boosted during the late 80's, when the study of additional physico-chemical pro...

Serum Hydroxyl Radical Scavenging Capacity as Quantified with Iron-Free Hydroxyl Radical Source

PubMed Central

Endo, Nobuyuki; Oowada, Shigeru; Sueishi, Yoshimi; Shimmei, Masashi; Makino, Keisuke; Fujii, Hirotada; Kotake, Yashige

2009-01-01

We have developed a simple ESR spin trapping based method for hydroxyl (OH) radical scavenging-capacity determination, using iron-free OH radical source. Instead of the widely used Fenton reaction, a short (typically 5 seconds) in situ UV-photolysis of a dilute hydrogen peroxide aqueous solution was employed to generate reproducible amounts of OH radicals. ESR spin trapping was applied to quantify OH radicals; the decrease in the OH radical level due to the specimen’s scavenging activity was converted into the OH radical scavenging capacity (rate). The validity of the method was confirmed in pure antioxidants, and the agreement with the previous data was satisfactory. In the second half of this work, the new method was applied to the sera of chronic renal failure (CRF) patients. We show for the first time that after hemodialysis, OH radical scavenging capacity of the CRF serum was restored to the level of healthy control. This method is simple and rapid, and the low concentration hydrogen peroxide is the only chemical added to the system, that could eliminate the complexity of iron-involved Fenton reactions or the use of the pulse-radiolysis system. PMID:19794928

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®

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.

The bright and dark side of Joseph Fenton: An analysis of narratives describing the man known as Sudharman.

PubMed

LeBlanc, Sarah Symonds; LeBlanc, Matthew M

2016-08-01

The death of Joe "Sudharman" Fenton sparked competing narratives leaving some members of the family wondering who Joe Fenton was, the man who died as Sudharman. During the night of July 4, 2010, Sudharman was murdered as he slept in his yoga studio in Union County, Pennsylvania. This piece examines his death in order to examine how communication was used to describe Joe Fenton. We used autoethnographic and ethnographic methods to collect the media coverage of his death, the funeral remembrances, and the blog posts, as well as completed two in-depth interviews with family members in order to find out who Joe Fenton was. We analyzed how others described Fenton through the frames of dark and bright communication behaviors. Our analysis determined that Fenton was seen in a spiritual/religious light, as he was described as god-like, a shining beacon and memorable. Dark communication described Fenton as being manipulative, deceitful, and, at times, emotionally abusive.

Double-shell Fe2O3 hollow box-like structure for enhanced photo-Fenton degradation of malachite green dye

NASA Astrophysics Data System (ADS)

Jiang, De Bin; Liu, Xiaoying; Xu, Xuan; Zhang, Yu Xin

2018-01-01

In this work we demonstrate the synthesis of novel Fe2O3 nanosheets with double-shell hollow morphology by replica molding from diatomite framework. The nanostructures of Fe2O3 nanosheets were examined by focused-ion-beam scanning electron microscopy (FIB/SEM), X-ray diffraction spectroscopy (XRD), Brunauer-Emmett-Teller (BET) specific surface area measurements and Fourier transform infrared (FT-IR) spectroscopy. The results reveal that (1) Pure Fe2O3 nanosheets were successfully obtained; (2) The double-shell Fe2O3 hollow structure achieved via the NaOH etching silica method was observed; (3) Fe2O3 nanosheets possessed uniformly distributed porous nanosheets. Such structural features enlarged the specific surface area of Fe2O3 nanosheets and led to more catalytic active sites. In the heterogeneous photo-Fenton reaction, the double-shell Fe2O3 hollow morphology exhibited excellent catalytic capability for the degradation of malachite green (MG) at circumneutral pH condition. Under optimum condition, MG solution was almost completely decolorized in 60 min (99.9%). The Fe2O3 nanosheets also showed good stability and recyclability, demonstrating great potential as a promising photo-Fenton catalyst for the effective degradation of MG dye in wastewater.

Chemical oxidation of a malodorous compound, indole, using iron entrapped in calcium alginate beads.

PubMed

Ben Hammouda, Samia; Adhoum, Nafaâ; Monser, Lotfi

2016-01-15

Iron-alginate beads (Fe-ABs) were successfully prepared by the ion-gelation method, and applied as heterogeneous Fenton catalysts for the removal of a malodorous compound 'indole'. Similarly, copper-enriched alginate beads (Cu-ABs) were synthesized and tested as like-Fenton catalyst, however, their application proved not to be effective for this purpose. Fe-ABs catalysts were characterized by FTIR, SEM, EDS and AAS spectroscopy. Results pointed out that the parameters affecting Fenton catalysis must be carefully chosen to avoid excessive iron release. Under optimal conditions, complete indole removal and considerably high reduction of TOC, without significant leaching was achieved. Indole decay followed a pseudo-first-order kinetics. The absolute rate constant for indole hydroxylation was 3.59×10(9) M(-1) s(-1), as determined by the competition kinetics method. Four reaction intermediates (Isatin, Dioxindole, Oxindole and Anthralinic acid) were identified by ULC/MS/MS analysis. Short-chain aliphatic carboxylic acids like formic, acetic, oxalic, maleic, oxamic and pyruvic acids were identified by ion exclusion chromatography and as end-products. Based on the identified by-products, a plausible mineralization pathway was proposed. Moreover, the catalyst was recovered quantitatively by simple filtration and reused for several times without significant loss of activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimization of pharmaceutical wastewater treatment by solar/ferrioxalate photo-catalysis.

PubMed

Monteagudo, J M; Durán, A; Culebradas, R; San Martín, I; Carnicer, A

2013-10-15

The degradation of a pharmaceutical wastewater using a ferrioxalate-assisted solar/photo-Fenton system has been studied. The photochemical reaction was carried out in a pilot plant consisting of a compound parabolic collector (CPC) solar reactor. An optimization study was performed combining a multivariate experimental design and Neuronal Networks that included the following variables: initial concentrations of H2O2, catalyst Fe (II) and oxalic acid (H2C2O4), temperature and solar power. Under optimal conditions, 84% TOC (Total Organic Carbon) removal was achieved in 115 min. Oxalic acid had a positive effect on mineralization when solar power was above 30 W m(-2). The minimum amount of H2O2 to degrade 1 mol of TOC was found to be 3.57 mol. Both the H2O2 conversion efficiency and the degree of mineralization were highest when the oxalic/Fe(II) initial molar relation was close to 3. HO radicals were the main oxidative intermediate species in the process, although hydroperoxyl radicals (HO(2)(·)) also played a role. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ferrocene-functionalized graphitic carbon nitride as an enhanced heterogeneous catalyst of Fenton reaction for degradation of Rhodamine B under visible light irradiation.

PubMed

Lin, Kun-Yi Andrew; Lin, Jyun-Ting

2017-09-01

To enhance degradation of Rhodamine B (RhB), a toxic xanthene dye, an iron-doped graphitic carbon nitride (CN) is prepared by establishing a covalent bond (-CN-) bridging ferrocene (Fc) and CN via a Schiff base reaction. The π-conjugation between the aromatic Fc and CN can be much enhanced by the covalent bond, thereby facilitating the bulk-to-surface charge transfer and separation as well as reversible photo-redox reactions during photocatalytic reactions. Thus, the resulting Fc-CN exhibits a much higher catalytic activity than CN to activate hydrogen peroxide (HP) for RhB degradation, because the photocatalytically generated electrons from CN can activate HP and effectively maintain the bivalence state of Fe in Fc, which also induces the activation of HP. The RhB degradation by the Fc-CN activated HP process (Fc-CN-HP) is validated to involve OH • by examining the effect of radical probe agent as well as electron paramagnetic resonance (EPR) spectroscopic analysis. Fc-CN is also proven to activate HP for RhB degradation over multiple times without loss of catalytic activity. Through determining the degradation intermediates, RhB is indeed fully decomposed by Fc-CN-HP into much lower-molecular-weight organic compounds. These features indicate that Fc-functionalization can be an advantageous technique to enhance the catalytic activity of CN for activating HP. The results obtained in this study are essential to further design and utilize Fc-functionalized CN for Fenton-like reactions. The findings shown here, especially the degradation mechanism and pathway, are also quite important for treating xanthene dyes in wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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.

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.

Nanoscale zero-valent iron incorporated with nanomagnetic diatomite for catalytic degradation of methylene blue in heterogeneous Fenton system.

PubMed

Zha, Yiming; Zhou, Ziqing; He, Haibo; Wang, Tianlin; Luo, Liqiang

2016-01-01

Nanoscale zero-valent iron (nZVI) incorporated with nanomagnetic diatomite (DE) composite material was prepared for catalytic degradation of methylene blue (MB) in heterogeneous Fenton system. The material was constructed by two facile steps: Fe3O4 magnetic nanoparticles were supported on DE by chemical co-precipitation method, after which nZVI was incorporated into magnetic DE by liquid-phase chemical reduction strategy. The as-prepared catalyst was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, magnetic properties measurement and nitrogen adsorption-desorption isotherm measurement. The novel nZVI@Fe3O4-diatomite nanocomposites showed a distinct catalytic activity and a desirable effect for degradation of MB. MB could be completely decolorized within 8 min and the removal efficiency of total organic carbon could reach to 90% after reaction for 1 h.

Effects of Solvent Diols on the Synthesis of ZnFe2O4 Particles and Their Use as Heterogeneous Photo-Fenton Catalysts

PubMed Central

Anchieta, Chayene Gonçalves; Cancelier, Adriano; Mazutti, Marcio Antonio; Jahn, Sérgio Luiz; Kuhn, Raquel Cristine; Gündel, Andre; Chiavone-Filho, Osvaldo; Foletto, Edson Luiz

2014-01-01

A solvothermal method was used to prepare zinc ferrite spinel oxide (ZnFe2O4) using ethylene glycol and 1,4 butanediol as solvent diols, and the influence of diols on the physical properties of ZnFe2O4 particles was investigated. The produced particles were characterized by X-ray powder diffraction (XRD), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption isotherms, and the catalytic activity for the organic pollutant decomposition by heterogeneous photo-Fenton reaction was investigated. Both solvents produced particles with cubic spinel structure. Microporous and mesoporous structures were obtained when ethylene glycol and 1,4 butanediol were used as diols, respectively. A higher pore volume and surface area, as well as a higher catalytic activity for the pollutant degradation were found when 1,4 butanediol was used as solvent. PMID:28788191

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

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

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.

Oxone/Fe[superscript 2+] Degradation of Food Dyes: Demonstration of Catalyst-Like Behavior and Kinetic Separation of Color

ERIC Educational Resources Information Center

Nalliah, Ruth E.

2015-01-01

A demonstration of the degradation of food coloring dyes by oxidation via the Fenton reaction can be substituted with a simpler demonstration using the oxidant oxone with iron(II) ions as an activator. The addition of small amounts of solid oxone and iron(II) sulfate to solutions containing mixtures of food coloring results in successive…

Degradation of ciprofloxacin antibiotic by Homogeneous Fenton oxidation: Hybrid AHP-PROMETHEE method, optimization, biodegradability improvement and identification of oxidized by-products.

PubMed

Salari, Marjan; Rakhshandehroo, Gholam Reza; Nikoo, Mohammad Reza

2018-09-01

The main purpose of this experimental study was to optimize Homogeneous Fenton oxidation (HFO) and identification of oxidized by-products from degradation of Ciprofloxacin (CIP) using hybrid AHP-PROMETHEE, Response Surface Methodology (RSM) and High Performance Liquid Chromatography coupled with Mass Spectrometry (HPLC-MS). At the first step, an assessment was made for performances of two catalysts (FeSO 4 ·7H 2 O and FeCl 2 ·4H 2 O) based on hybrid AHP-PROMETHEE decision making method. Then, RSM was utilized to examine and optimize the influence of different variables including initial CIP concentration, Fe 2+ concentration, [H 2 O 2 ]/[ Fe 2+ ] mole ratio and initial pH as independent variables on CIP removal, COD removal, and sludge to iron (SIR) as the response functions in a reaction time of 25 min. Weights of the mentioned responses as well as cost criteria were determined by AHP model based on pairwise comparison and then used as inputs to PROMETHEE method to develop hybrid AHP-PROMETHEE. Based on net flow results of this hybrid model, FeCl 2 ·4H 2 O was more efficient because of its less environmental stability as well as lower SIR production. Then, optimization of experiments using Central Composite Design (CCD) under RSM was performed with the FeCl 2 ·4H 2 O catalyst. Biodegradability of wastewater was determined in terms of BOD 5 /COD ratio, showing that HFO process is able to improve wastewater biodegradability from zero to 0.42. Finally, the main intermediaries of degradation and degradation pathways of CIP were investigated with (HPLC-MS). Major degradation pathways from hydroxylation of both piperazine and quinolonic rings, oxidation and cleavage of the piperazine ring, and defluorination (OH/F substitution) were suggested. Copyright © 2018 Elsevier Ltd. All rights reserved.

An activated carbon fiber cathode for the degradation of glyphosate in aqueous solutions by the Electro-Fenton mode: Optimal operational conditions and the deposition of iron on cathode on electrode reusability.

PubMed

Lan, Huachun; He, Wenjing; Wang, Aimin; Liu, Ruiping; Liu, Huijuan; Qu, Jiuhui; Huang, C P

2016-11-15

An activated carbon fiber (ACF) cathode was fabricated and used to treat glyphosate containing wastewater by the Electro-Fenton (EF) process. The results showed that glyphosate was rapidly and efficiently degraded and the BOD 5 /COD ratio was increased to >0.3 implying the feasibility of subsequent treatment of the treated wastewater by biological methods. The results of ion chromatography and HPLC measurements indicated that glyphosate was completely decomposed. Effective OH generation and rapid recycling/recovery of the Fe 2+ ions at the cathode were responsible primarily for the high performance of the ACF-EF process. Factors such as inlet oxygen gas flow rate, Fe 2+ dosage, initial glyphosate concentration, applied current intensity, and solution pH that may affect the efficiency of the ACF-EF process were further studied and the optimum operation condition was established. Results of SEM/EDX, BET and XPS analysis showed the deposition of highly dispersed fine Fe 2 O 3 particles on the ACF surface during the EF reaction. The possibility of using the Fe 2 O 3 -ACF as iron source in the EF process was assessed. Results showed that the Fe 2 O 3 -ACF electrode was effective in degrading glyphosate in the EF process. The deposition of Fe 2 O 3 particles on the ACF electrode had no adverse effect on the reusability of the ACF cathode. Copyright © 2016. Published by Elsevier Ltd.

The role of iron species on the turbidity of oxidized phenol solutions in a photo-Fenton system.

PubMed

Villota, Natalia; Camarero, Luis M; Lomas, Jose M; Perez-Arce, Jonatan

2015-01-01

This work aims at establishing the contribution of the iron species to the turbidity of phenol solutions oxidized with photo-Fenton technology. During oxidation, turbidity increases linearly with time till a maximum value, according to a formation rate that shows a dependence of second order with respect to the catalyst concentration. Next, the decrease in turbidity shows the evolution of second-order kinetics, where the kinetics constant is inversely proportional to the dosage of iron, of order 0.7. The concentration of iron species is analysed at the point of maximum turbidity, as a function of the total amount of iron. Then, it is found that using dosages FeT=0-15.0 mg/L, the majority iron species was found to be ferrous ions, indicating that its concentration increases linearly with the dosage of total iron. This result may indicate that the photo-reaction of ferric ion occurs leading to the regeneration of ferrous ion. The results, obtained by operating with initial dosages FeT=15.0 and 25.0 mg/L, suggest that ferrous ion concentration decreases while ferric ion concentration increases in a complementary manner. This fact could be explained as a regeneration cycle of the iron species. The observed turbidity is generated due to the iron being added as a catalyst and the organic matter present in the system. Later, it was found that at the point of maximum turbidity, the concentration of ferrous ions is inversely proportional to the concentration of phenol and its dihydroxylated intermediates.

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.

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.

Degradation of polycyclic aromatic hydrocarbons (PAHs) in textile dyeing sludge with ultrasound and Fenton processes: Effect of system parameters and synergistic effect study.

PubMed

Lin, Meiqing; Ning, Xun-an; An, Taicheng; Zhang, Jianhao; Chen, Changmin; Ke, Yaowei; Wang, Yujie; Zhang, Yaping; Sun, Jian; Liu, Jingyong

2016-04-15

To establish an efficient oxidation process for the degradation of polycyclic aromatic hydrocarbons (PAHs) in textile dyeing sludge, the effects of various operating parameters were optimized during the ultrasound process, Fenton process and the combined ultrasound-Fenton process. The results showed that the ultrasonic density of 1.80w/cm(3), both H2O2 and Fe(2+) dosages of 140mmol/L and pH 3 were favorable conditions for the degradation of PAHs. The degradation efficiency of high molecular weight PAHs was close to or even higher than that of light molecular weight PAHs. The highest degradation efficiencies of Σ16 PAHs were obtained within 30min in the order of: Fenton (83.5%) >ultrasound-Fenton (75.5%) >ultrasound (45.5%), then the efficiencies were decreased in the other of: ultrasound-Fenton (73.0%) >Fenton (70.3%) >ultrasound (41.4%) in 60min. The extra PAHs were released from the intracellular substances and the cavities of sludge due to the disruption of sludge during the oxidation process. Also, the degradation of PAHs could be inhibited by the other organic matter in the sludge. The combined ultrasound-Fenton process showed more efficient than both ultrasound process and Fenton process not only in the surface of sludge but also in the sludge interior. Copyright © 2015 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.

Citric acid assisted Fenton-like process for enhanced dewaterability of waste activated sludge with in-situ generation of hydrogen peroxide.

PubMed

Xiao, Keke; Pei, Kangyue; Wang, Hui; Yu, Wenbo; Liang, Sha; Hu, Jingping; Hou, Huijie; Liu, Bingchuan; Yang, Jiakuan

2018-09-01

Fenton's reagent has been widely used to enhance sludge dewaterability. However, drawbacks associated with hydrogen peroxide (H 2 O 2 ) in Fenton's reagents exist, since it is a hazardous chemical and shows carcinogenicity, explosivity, instability, and corrosivity. Moreover, initial acidification and subsequent neutralization are needed as optimal conditions for homogeneous Fenton conditioning and final filtrate discharge. In this study, a Fenton-like process for the enhanced dewaterability of waste activated sludge with in-situ generation of H 2 O 2 and without extra pH adjustment was firstly proposed, namely citric acid (CA)-assisted oxygen activation in an air/nano zero-valent iron (nZVI) system and chemical re-coagulation with polydiallyldimethylammonium chloride (PDMDAAC). Using the response surface methodology (RSM), the optimal doses of CA, nZVI, and PDMDAAC were determined to be 13, 33, and 9 mg g -1 dry solids (DS), respectively. This composite conditioner showed a good dewatering capability compared with the raw sludge, e.g. the capillary suction time decreased from 130.0 to 9.5 s. The enhanced sludge dewaterability was further confirmed by laboratory-scale diaphragm filter press dewatering tests, which produced a lower cake moisture content compared with the raw sludge, and the final pH of the filtrate was close to neutrality. The citric acid promoted the production of H 2 O 2 and Fe(II)/Fe(III) species, the degradation of protein in tightly-bound extracellular polymeric substances, and the decomposition of protein-N in the solid phase of sludge, resulting a greater conversion of bound water to free water. The results of electron spin resonance indicated that the hydroxyl radicals were mainly responsible for the decomposition of proteinaceous compounds. The subsequent chemical re-coagulation with PDMDAAC can make the zeta potential of sludge samples less negative, reduce the repulsive electrostatic interactions, and agglomerate the smaller particles into larger aggregates, thus enhancing sludge dewaterability. Copyright © 2018 Elsevier Ltd. All rights reserved.

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.

Pretreatment of lignocellulosic biomass using Fenton chemistry.

PubMed

Kato, Dawn M; Elía, Noelia; Flythe, Michael; Lynn, Bert C

2014-06-01

In an attempt to mimic white-rot fungi lignin degradation via in vivo Fenton chemistry, solution phase Fenton chemistry (10 g biomass, 176 mmol hydrogen peroxide and 1.25 mmol Fe(2+) in 200 mL of water) was applied to four different biomass feedstocks. An enzymatic saccharification of Fenton pretreated biomass showed an average 212% increase relative to untreated control across all four feedstocks (P<0.05, statistically significant). A microbial fermentation of the same Fenton pretreated biomass showed a threefold increase in gas production upon a sequential co-culture with Clostridium thermocellum and Clostridium beijerinckii. These results demonstrate the use of solution phase Fenton chemistry as a viable pretreatment method to make cellulose more bioavailable for microbial biofuel conversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Coupling solar photo-Fenton and biotreatment at industrial scale: main results of a demonstration plant.

PubMed

Malato, Sixto; Blanco, Julián; Maldonado, Manuel I; Oller, Isabel; Gernjak, Wolfgang; Pérez-Estrada, Leonidas

2007-07-31

This paper reports on the combined solar photo-Fenton/biological treatment of an industrial effluent (initial total organic carbon, TOC, around 500mgL(-1)) containing a non-biodegradable organic substance (alpha-methylphenylglycine at 500mgL(-1)), focusing on pilot plant tests performed for design of an industrial plant, the design itself and the plant layout. Pilot plant tests have demonstrated that biodegradability enhancement is closely related to disappearance of the parent compound, for which a certain illumination time and hydrogen peroxide consumption are required, working at pH 2.8 and adding Fe(2+)=20mgL(-1). Based on pilot plant results, an industrial plant with 100m(2) of CPC collectors for a 250L/h treatment capacity has been designed. The solar system discharges the wastewater (WW) pre-treated by photo-Fenton into a biotreatment based on an immobilized biomass reactor. First, results of the industrial plant are also presented, demonstrating that it is able to treat up to 500Lh(-1) at an average solar ultraviolet radiation of 22.9Wm(-2), under the same conditions (pH, hydrogen peroxide consumption) tested in the pilot plant.

A Response to Edwin Fenton. An Exchange of Views between Edwin Fenton and Jack R. Fraenkel, the Cognitive-Developmental Approach to Moral Education

ERIC Educational Resources Information Center

Fraenkel, Jack R.

1977-01-01

Restatement of the author's criticisms of Fenton's article about Kohlberg's cognitive-developmental approach to moral education in the April 1976 issue of "Social Education." Emphasis is made that (1) Fenton's definitive summations of Kohlberg's works should be more tentative and cautious, because (2) some parts of moral developmental research are…

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.

Chaperonins: The hunt for the Group II mechanism.

PubMed

Bigotti, Maria Giulia; Clarke, Anthony R

2008-06-15

Chaperonins are multi-subunit complexes that enhance the efficiency of protein-folding reactions by capturing protein substrates in their central cavities. They occur in all prokaryotic and eukaryotic cell types and, alone amongst molecular chaperones, chaperonin knockouts are always lethal. Chaperonins come in two forms; the Group I are found in bacteria, mitochondria and plastids [W.A. Fenton, A.L. Horwich, Q. Rev. Biophys. 36 (2003) 229-256, [1

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.

Genotoxicity of tungsten carbide-cobalt (WC-Co) nanoparticles in vitro: mechanisms-of-action studies.

PubMed

Moche, Hélène; Chevalier, Dany; Vezin, Hervé; Claude, Nancy; Lorge, Elisabeth; Nesslany, Fabrice

2015-02-01

We showed previously that tungsten carbide-cobalt (WC-Co) nanoparticles (NP) can be used as a nanoparticulate positive control in some in vitro mammalian genotoxicity assays. Here, we investigate the mechanisms of action involved in WC-Co NP genotoxicity in L5178Y mouse lymphoma cells and primary human lymphocytes, in vitro. Data from the micronucleus assay coupled with centromere staining and from the chromosome-aberration assay show the involvement of both clastogenic and aneugenic events. Experiments with the formamidopyrimidine DNA glycosylase (FPG)-modified comet assay showed a slight (non-significant) increase in FPG-sensitive sites in the L5178Y mouse lymphoma cells but not in the human lymphocytes. Electron paramagnetic resonance spin-trapping results showed the presence of hydroxyl radicals (•OH) in WC-Co NP suspensions, with or without cells, but with time-dependent production in the presence of cells. However, a significant difference in •OH production was observed between human lymphocytes from two different donors. Using H2O2, we showed that WC-Co NP can participate in Fenton-like reactions. Thus, •OH might be produced either via intrinsic generation by WC-Co NP or through a Fenton-like reaction in the presence of cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Radioprotective properties of apple polyphenols: an in vitro study.

PubMed

Chaudhary, Pankaj; Shukla, Sandeep Kumar; Kumar, I Prem; Namita, I; Afrin, Farhat; Sharma, Rakesh Kumar

2006-08-01

Present study was undertaken to evaluate the radioprotective ability of total polyphenols extracted from edible portion (epicarp and mesocarp) of apple. Prior administration of apple polyphenols to murine thymocytes significantly countered radiation induced DNA damage (evaluated by alkaline halo assay) and cell death (trypan blue exclusion method) in a dose dependent manner maximally at a concentration of 2 and 0.2 mg/ml respectively. Apple polyphenols in a dose dependent fashion inhibited both radiation or Fenton reaction mediated 2-deoxyribose (2-DR) degradation indicating its ability to scavenge hydroxyl radicals and this activity was found to be unaltered in presence of simulated gastric juice. Similarly apple polyphenols in a dose dependent fashion scavenged DPPH radicals (maximum 69% at 1 mg/ml), superoxide anions (maximum 88% at 2 mg/ml), reduced Fe(3 +) to Fe(2 +) (maximum at 1 mg/ml) and inhibited Fenton reaction mediated lipid peroxidation (maximum 66% at 1.5 mg/ml) further establishing its antioxidative properties. Studies carried out with plasmid DNA revealed the ability of apple polyphenols to inhibit radiation induced single as well as double strand breaks. The results clearly indicate that apple polyphenols have significant potential to protect cellular system from radiation induced damage and ability to scavenge free radicals might be playing an important role in its radioprotective manifestation.

76 FR 40350 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

...: Fenton Power Partners I, LLC. Description: Fenton Power Partners I, LLC submits tariff filing per 35: Fenton Seller Category Compliance Filing to be effective 6/30/2011. Filed Date: 06/29/2011. Accession...

Photocatalytic treatment of an industrial effluent using artificial and solar UV radiation: an operational cost study on a pilot plant scale.

PubMed

Durán, A; Monteagudo, J M; San Martín, I

2012-05-15

The aim of this work was to study the operation costs of treating a real effluent from an integrated gasification combined cycle (IGCC) power station located in Spain. The study compares different homogeneous photocatalytic processes on a pilot plant scale using different types of radiation (artificial UV or solar UV with a compound parabolic collector). The efficiency of the processes was evaluated by an analysis of the total organic carbon (TOC) removed. The following processes were considered in the study: (i) a photo-Fenton process at an artificial UV pilot plant (with the initial addition of H(2)O(2)), (ii) a modified photo-Fenton process with continuous addition of H(2)O(2) and O(2) to the system and (iii) a ferrioxalate-assisted solar photo-Fenton process at a compound parabolic collector (CPC) pilot plant. The efficiency of these processes in degrading pollutants has been studied previously, and the results obtained in each of those studies have been published elsewhere. The operational costs due to the consumption of electrical energy, reagents and catalysts were calculated from the optimal conditions of each process. The results showed that the solar photo-Fenton system was economically feasible, being able to achieve up to 75% mineralization with a total cost of 6 €/m(3), which can be reduced to 3.6 €/m(3) by subtracting the electrical costs because the IGCC plant is self-sufficient in terms of energy. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

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.

Treatment of industrial effluents by electrochemical generation of H2O2 using an RVC cathode in a parallel plate reactor.

PubMed

Bustos, Yaneth A; Rangel-Peraza, Jesús Gabriel; Rojas-Valencia, Ma Neftalí; Bandala, Erick R; Álvarez-Gallegos, Alberto; Vargas-Estrada, Laura

2016-01-01

Electrochemical techniques have been used for the discolouration of synthetic textile industrial wastewater by Fenton's process using a parallel plate reactor with a reticulated vitreous carbon (RVC) cathode. It has been shown that RVC is capable of electro-generating and activating H2O2 in the presence of Fe(2+) added as catalyst and using a stainless steel mesh as anode material. A catholyte comprising 0.05 M Na2SO4, 0.001 M FeSO4.7H2O, 0.01 M H2SO4 and fed with oxygen was used to activate H2O2.The anolyte contained only 0.8 M H2SO4. The operating experimental conditions were 170 mA (2.0 V < ΔECell < 3.0 V) to generate 5.3 mM H2O2. Synthetic effluents containing various concentrations (millimolar - mM) of three different dyes, Blue Basic 9 (BB9), Reactive Black 5 (RB5) and Acid Orange 7 (AO7), were evaluated for discolouration using the electro-assisted Fenton reaction. Water discolouration was measured by UV-VIS absorbance reduction. Dye removal by electrolysis was a function of time: 90% discolouration of 0.08, 0.04 and 0.02 mM BB9 was obtained at 14, 10 and 6 min, respectively. In the same way, 90% discolouration of 0.063, 0.031 and 0.016 mM RB5 was achieved at 90, 60 and 30 min, respectively. Finally, 90% discolouration of 0.14, 0.07 and 0.035 mM AO7 was achieved at 70, 40 and 20 min, respectively. The experimental results confirmed the effectiveness of electro-assisted Fenton reaction as a strong oxidizing process in water discolouration and the ability of RVC cathode to electro-generate and activate H2O2 in situ.

Evidences of extracellular abiotic degradation of hexadecane through free radical mechanism induced by the secreted phenazine compounds of P. aeruginosa NY3.

PubMed

Nie, Hongyun; Nie, Maiqian; Wang, Lei; Diwu, Zhenjun; Xiao, Ting; Qiao, Qi; Wang, Yan; Jiang, Xin

2018-03-02

The aim of this work was to investigate the effects of secreted extracellular phenazine compounds (PHCs) on the degradation efficiency of alkanes by P. aeruginosa NY3. Under aerobic conditions, the PHCs secreted by P. aeruginosa NY3 initiate the oxidation of alkanes outside cells, in coupling with some reducing agents, such as β-Nicotinamide adenine dinucleotide, reduced disodium salt (NADH) or reduced glutathione (GSH). This reaction might be via free radical reactions similar to Fenton Oxidation Reaction (FOR). P. aeruginosa NY3 secretes pyocyanin (Pyo), 1-hydroxyphenazine (HPE), phenazine-1-carboxylic acid (PCA), and phenazine-1-amide (PCN) simultaneously. The cell-free extracellular fluid containing these four PHCs degrades hexadecane effectively. The observation of Electron Spin Resonance (EPR) signals of superoxide anion radical (O 2 - ), hydroxyl radical (OH) and/or carbon free radicals (R) both in vivo and in vitro suggested the degradation of hexadecane could be via a free radical pathway. Secretion of PHCs has been found to be characteristic of Pseudomonas which is often involved in or related to the degradation of organic pollutants. Our work suggested that certain organic contaminants may be oxidized through ubiquitously extracellular abiotic degradation by the free radicals produced during bio-remediation and bio-treatment. Copyright © 2018. Published by Elsevier Ltd.

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.

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...

Dopamine, 6-hydroxydopamine, iron, and dioxygen--their mutual interactions and possible implication in the development of Parkinson's disease.

PubMed

Linert, W; Herlinger, E; Jameson, R F; Kienzl, E; Jellinger, K; Youdim, M B

1996-08-23

The reactions of dopamine (1-amino-2-(3,4-dihydroxyphenyl)-ethane, DA), 5-hydroxydopamine (5-OHDA), and 6-hydroxydopamine (6-OHDA), with molecular oxygen-with and without the addition of catalytic amounts of iron(III) and other metal ions-have been studied and the implication of these results with respect to the chemistry involved in the progress of Parkinson's disease is discussed. In the presence of O2 DA reacts spontaneously without the necessity of metal-ion catalysis under the production of stoichiometric amounts of H2O2, to form initially pink dopaminochrome, which is not stable and reacts further (without the consumption of dioxygen) to form the insoluble polymeric material known as 'melanine'. DA reacts with iron(III) yielding an intermediate 1:1 complex, which decomposes releasing Fe(II) and the semiquinone, which reacts further under involvement of both Fe(III) and dioxygen. 6-OHDA reacts without showing the necessity of such an intermediate, and it is shown to be able to release iron as Fe(II) from ferritine. On the other hand, it is shown (in vitro) that Fe(II) reacts in a Fenton type reaction with DA and the present H2O2 producing 5-OHDA and especially 6-OHDA. Based on these mutual interacting reactions a mechanism for the initiation and progress of Parkinson's disease is suggested. The catalytic effects of some other transition-metal ions are presented and an explanation for the peculiarly toxic effects of manganese(II) is put forward. Finally, a possible reason for the effect that nicotine has in the mitigation of Parkinson's disease is discussed.

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.

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.

Iron toxicity in the retina requires Alu RNA and the NLRP3 inflammasome

PubMed Central

Gelfand, Bradley D.; Wright, Charles B.; Kim, Younghee; Yasuma, Tetsuhiro; Yasuma, Reo; Li, Shengjian; Fowler, Benjamin J.; Bastos-Carvalho, Ana; Kerur, Nagaraj; Uittenbogaard, Annette; Han, Youn Seon; Lou, Dingyuan; Kleinman, Mark E.; McDonald, W. Hayes; Núñez, Gabriel; Georgel, Philippe; Dunaief, Joshua L.; Ambati, Jayakrishna

2015-01-01

Excess iron induces tissue damage and is implicated in age-related macular degeneration (AMD). Iron toxicity is widely attributed to hydroxyl radical formation through Fenton's reaction. We report that excess iron, but not other Fenton catalytic metals, induces activation of the NLRP3 inflammasome, a pathway also implicated in AMD. Additionally, iron-induced degeneration of the retinal pigmented epithelium (RPE) is suppressed in mice lacking inflammasome components Caspase-1/11 or Nlrp3 or by inhibition of Caspase-1. Iron overload increases abundance of RNAs transcribed from short interspersed nuclear elements (SINEs): Alu RNAs and the rodent equivalent B1 and B2 RNAs, which are inflammasome agonists. Targeting Alu or B2 RNA prevents iron-induced inflammasome activation and RPE degeneration. Iron-induced SINE RNA accumulation is due to suppression of DICER1 via sequestration of the co-factor poly(C)-binding protein 2 (PCBP2). These findings reveal an unexpected mechanism of iron toxicity, with implications for AMD and neurodegenerative diseases associated with excess iron. PMID:26074074

Cellular redox homeostasis in endothelial cells treated with nonmodified and Fenton-modified nanodiamond powders.

PubMed

Solarska-Ściuk, K; Gajewska, A; Skolimowski, J; Gajek, A; Bartosz, G

2014-01-01

Diamond nanoparticles find numerous applications in pharmacy, medicine, cosmetics, and biotechnology. However, possible adverse cellular effects of diamond nanoparticle cells have been reported, which may limit their use. The aim of this study was to compare the effect of nonmodified diamond nanoparticles (D) and diamond nanoparticles modified by the Fenton reaction (D+OH) on human umbilical cord endothelial cells (HUVEC-ST). We found that both D and D+OH show time- and concentration-dependent cytotoxicity, inducing apoptosis and necrosis of HUVEC-ST. Interaction with D and D+OH also induced changes in the production of reactive oxygen and nitrogen species and changes in the level of glutathione and activities of antioxidant enzymes in the cells. These data demonstrate that diamond nanoparticles may induce oxidative stress in human endothelial cells, which contributes to their cytotoxic effects seen at higher concentrations of D and D+OH. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Fast Fenton footprinting: a laboratory-based method for the time-resolved analysis of DNA, RNA and proteins

PubMed Central

Shcherbakova, Inna; Mitra, Somdeb; Beer, Robert H.; Brenowitz, Michael

2006-01-01

‘Footprinting’ describes assays in which ligand binding or structure formation protects polymers such as nucleic acids and proteins from either cleavage or modification; footprinting allows the accessibility of individual residues to be mapped in solution. Equilibrium and time-dependent footprinting links site-specific structural information with thermodynamic and kinetic transitions. The hydroxyl radical (·OH) is a particularly valuable footprinting probe by virtue of it being among the most reactive of chemical oxidants; it reports the solvent accessibility of reactive sites on macromolecules with as fine as a single residue resolution. A novel method of millisecond time-resolved ·OH footprinting has been developed based on the Fenton reaction, Fe(II) + H2O2 → Fe(III) + ·OH + OH−. This method can be implemented in laboratories using widely available three-syringe quench flow mixers and inexpensive reagents to study local changes in the solvent accessibility of DNA, RNA and proteins associated with their biological function. PMID:16582097

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.

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...

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

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.

Transferrin facilitates the formation of DNA double-strand breaks via transferrin receptor 1: the possible involvement of transferrin in carcinogenesis of high-grade serous ovarian cancer.

PubMed

Shigeta, S; Toyoshima, M; Kitatani, K; Ishibashi, M; Usui, T; Yaegashi, N

2016-07-07

Fallopian tubal epithelium is a candidate for the origin of high-grade serous ovarian cancer. Transferrin-containing follicular fluid and/or retrograde menstrual blood are possible risk factors for carcinogenesis. Accumulation of DNA double-strand breaks (DNA-DSBs) in the fallopian tubal epithelium is considered to play an important role in the development of cancer. However, the mechanisms by which DNA-DSBs accumulate have not yet been fully elucidated. The hydroxyl radical, which is produced in a Fenton reaction catalyzed by an iron ion, serves as a potent DNA-DSB-inducing molecule, raising the potential of an iron ion transporter of transferrin in the formation of DNA-DSBs. We studied the potential involvement of transferrin in DNA damage and the development of ovarian cancer. Treatment with transferrin facilitated the formation of histone 2AX phosphorylated at Serine 139 (γH2AX), which is known as a DNA-DSB marker, in human fallopian tube secretory epithelial cells and A2780 ovarian cancer cells. Knockdown of transferrin receptor 1 (TfR1), but not transferrin receptor 2, suppressed the transferrin uptake and consequent formation of γH2AX. As hydroxyl radicals in reactive oxygen species (ROS) are involved in DNA-DSBs, the formation of ROS was determined. Treatment with TfR1-specific small interference RNAs significantly diminished transferrin-induced formation of ROS. Moreover, TfR1-dependent uptake of transferrin was revealed to augment the formation of DNA-DSBs in the presence of hydrogen peroxide, which served as a substrate for the Fenton reaction. An ex vivo study with murine fallopian tubes further demonstrated that transferrin treatment introduced DNA-DSBs in the fallopian tubal epithelium. Collectively, these data suggested that the transferrin-TfR1 axis accounts for the induction of DNA-DSBs that potentially lead to DNA damage/genome instability. These findings also suggested that exposure to transferrin initiates and promotes the development of ovarian cancer by aiding the accumulation of DNA-DSBs in the fallopian tubal epithelium.

Synthesis and characterization of Bi{sub 1.56}Sb{sub 1.48}Co{sub 0.96}O{sub 7} pyrochlore sun-light-responsive photocatalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naceur, Benhadria, E-mail: nacer1974@yahoo.fr; Abdelkader, Elaziouti, E-mail: elaziouti_a@yahoo.com; Dr Moulay Tahar University, Saida

2016-02-15

Graphical abstract: Heterogeneous photo Fenton process with dye sensitized mechanism of RhB by Bi{sub 1.56}Sb{sub 1.48}Co{sub 0.96}O{sub 7} compound. - Highlights: • Bi{sub 1.56}Sb{sub 1.48}Co{sub 0.96}O{sub 7} (BSCO) catalyst was synthesized by improved solid state reaction method. • BSCO/H{sub 2}O{sub 2}/UVA and BSCO/H{sub 2}O{sub 2}/SL catalyst systems exhibit excellent photocatalytic activities for rhodamine B. • The photocatalytic degradation was preceded via heterogeneous photo Fenton mechanism process. • ·OH radicals are the main reactive species for the degradation of RhB. - Abstract: Novel nanostructure pyrochlore Bi{sub 1.56}Sb{sub 1.48}Co{sub 0.96}O{sub 7} was successfully synthesized via solid state reaction method in air. Themore » as-synthesized photocatalyst was characterized by X-ray diffraction, Scanning electron microscopy and UV–vis diffuse reflectance spectroscopy techniques. The results showed that the BSCO was crystallized with the pyrochlore-type structure, cubic crystal system and space group Fd3m. The average particle size and band gap for BSCO were D = 76.29 nm and E{sub g} = 1.50 eV respectively. Under the optimum conditions for discoloration of the dye: initial concentration of 20 mg L{sup −1} RhB, pH 7, 25 °C, 0.5 mL H{sub 2}O{sub 2} and BSCO/dye mass ration of 1 g L{sup −1}, 97.77 and 90.16% of RhB were removed with BSCO/H{sub 2}O{sub 2} photocatalytic system within 60 min of irradiation time under UVA- and SL irradiations respectively. Pseudo-second-order kinetic model gave the best fit, with highest correlation coefficients (R{sup 2} ≥ 0.99). On the base of these results, the mechanism of the enhancement of the discoloration efficiency was discussed. .« less

Kinetic studies of the reaction between pesticides and hydroxyl radical generated by laser flash photolysis.

PubMed

Gozzi, Fábio; Oliveira, Silvio C; Dantas, Renato F; Silva, Volnir O; Quina, Frank H; Machulek, Amilcar

2016-03-30

Due to contamination of the environment by pesticides and their mishandling, there is the need for treatment of contaminated sites and correct disposal of materials containing them. Thus, studies with advanced oxidation processes are expanding and can determine the rate constant of the hydroxyl radical with organic compounds of great importance in environmental contamination. In this context, the use of laser flash photolysis has been shown to be viable for the determination of these constants. The reaction rate constants of different pesticides with HO(•) in degassed acetonitrile have been determined. They were 1.6 × 10(9)  M(-1)  s(-1), 0.6 × 10(9)  M(-1)  s(-1), 1.2 × 10(9)  M(-1)  s(-1), 2.4 × 10(9)  M(-1)  s(-1) and 2.2 × 10(9)  M(-1)  s(-1) for the pesticides carbaryl, propoxur, fenoxycarb, ethoxysulfuron and chlorimuron-ethyl, respectively. These values are about an order of magnitude smaller than the diffusion controlled rate and correlate with the relative rates of disappearance of the pesticides in the photo-Fenton reaction in water. The correlation of the relative rate constants determined by laser flash photolysis with the relative rates of photo-Fenton degradation of the pesticides is compelling evidence for the participation of the hydroxyl radical in the degradation of these pesticides in the latter system. © 2015 Society of Chemical Industry.

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 ...

An overview on the removal of synthetic dyes from water by electrochemical advanced oxidation processes.

PubMed

Nidheesh, P V; Zhou, Minghua; Oturan, Mehmet A

2018-04-01

Wastewater containing dyes are one of the major threats to our environment. Conventional methods are insufficient for the removal of these persistent organic pollutants. Recently much attention has been received for the oxidative removal of various organic pollutants by electrochemically generated hydroxyl radical. This review article aims to provide the recent trends in the field of various Electrochemical Advanced Oxidation Processes (EAOPs) used for removing dyes from water medium. The characteristics, fundamentals and recent advances in each processes namely anodic oxidation, electro-Fenton, peroxicoagulation, fered Fenton, anodic Fenton, photoelectro-Fenton, sonoelectro-Fenton, bioelectro-Fenton etc. have been examined in detail. These processes have great potential to destroy persistent organic pollutants in aqueous medium and most of the studies reported complete removal of dyes from water. The great capacity of these processes indicates that EAOPs constitute a promising technology for the treatment of the dye contaminated effluents. Copyright © 2018 Elsevier Ltd. 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).

Reactive oxygen and iron species monitoring to investigate the electro-Fenton performances. Impact of the electrochemical process on the biodegradability of metronidazole and its by-products.

PubMed

Aboudalle, Arwa; Fourcade, Florence; Assadi, Aymen Amin; Domergue, Lionel; Djelal, Hayet; Lendormi, Thomas; Taha, Samir; Amrane, Abdeltif

2018-05-01

In this study, the monitoring of reactive oxygen species and the regeneration of the ferrous ions catalyst were performed during electro-Fenton (EF) process to highlight the influence of operating parameters. The removal of metronidazole (MTZ) was implemented in an electrochemical mono-compartment batch reactor under various ranges of current densities, initial MTZ and ferrous ions concentrations, and pH values. It was found that under 0.07 mA cm -2 , 0.1 mM of ferrous ions and pH = 3, the efficiency of 100 mg L -1 MTZ degradation and mineralization were 100% within 20 min and 40% within 135 min of electrolysis, respectively. The highest hydrogen peroxide and hydroxyl radical concentrations, 1.4 mM and 2.28 mM respectively, were obtained at 60 min electrolysis at 0.07 mA cm -2 . Improvement of the biodegradability was reached from 60 min of electrolysis with a BOD 5 /COD ratio above 0.4, which was reinforced by a respirometric study, that supports the feasibility of coupling electro-Fenton and biological treatment for the metronidazole removal. Copyright © 2018 Elsevier Ltd. All rights reserved.

Removal of β-lactam antibiotics from pharmaceutical wastewaters using photo-Fenton process at near-neutral pH.

PubMed

Giraldo-Aguirre, Ana L; Serna-Galvis, Efraím A; Erazo-Erazo, Edgar D; Silva-Agredo, Javier; Giraldo-Ospina, Héctor; Flórez-Acosta, Oscar A; Torres-Palma, Ricardo A

2017-02-03

In this work, the photo-Fenton process at near-neutral pH was applied for the removal of the β-lactam antibiotic oxacillin (OXA) in water using artificial and sunlight. Initially, the main variables of the process (Fe(II), H 2 O 2 , and light power) were optimized by a statistical factorial design (2 3 with center points). The experimental design indicated that 90 μmol L -1 of Fe(II), 10 mmol L -1 of H 2 O 2 , and 30 W of power light were the favorable conditions for degradation of OXA at 203 μmol L -1 . In the photo-Fenton system, the H 2 O 2 alone, UV-light/H 2 O 2 , and Fe(II)/H 2 O 2 subsystems presented a significant participation on antibiotic removal. Moreover, based on the primary organic transformation products, a mechanism of OXA degradation was proposed. Under the favorable operational conditions, both the pollutant and the antimicrobial activity were eliminated after 50 min of process application. Although at 480 min of treatment, only 5% of mineralization was achieved, the level of biodegradability of the solutions increased from 0.08 to 0.98. Interestingly, the presence of pharmaceutical additives (glucose, isopropanol, and oxalic acid) had a moderate interference on the efficiency of the pollutant removal. Additionally, the treatment at pilot scale of the β-lactam antibiotic in a pharmaceutical complex matrix using solar radiation allowed the complete removal of the pollutant and its associated antimicrobial activity in a very short time period (5 min). These results evidenced the applicability of the photo-Fenton process to treat wastewaters from pharmaceutical industry loaded with β-lactam antibiotics at near neutral pH values efficiently.

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.

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.

Degradation of chloroacetanilide herbicides by anodic fenton treatment.

PubMed

Friedman, Carey L; Lemley, Ann T; Hay, Anthony

2006-04-05

Anodic Fenton treatment (AFT) is an electrochemical treatment employing the Fenton reaction for the generation of hydroxyl radicals, strong oxidants that can degrade organic compounds via hydrogen abstraction. AFT has potential use for the remediation of aqueous pesticide waste. The degradation rates of chloroacetanilides by AFT were investigated in this work, which demonstrates that AFT can be used to rapidly and completely remove chloroacetanilide herbicides from aqueous solutions. Acetochlor, alachlor, butachlor, metolachlor, and propachlor were treated by AFT, and parent compound concentrations were analyzed over the course of the treatment time. Degradation curves were plotted and fitted by the AFT kinetic model for each herbicide, and AFT model kinetic parameters were used to calculate degradation rate constants. The reactivity order of these five active ingredients toward hydroxyl radical was acetochlor approximately metolachlor > butachlor approximately alachlor > propachlor. Treatment of the chloroacetanilides by AFT removed the parent compounds but did not completely mineralize them. However, AFT did result in an increase in the biodegradability of chloroacetanilide aqueous solutions, as evidenced by an increase in the 5-day biochemical oxygen demand to chemical oxygen demand ratio (BOD5/COD) to >0.3, indicating completely biodegradable solutions. Several degradation products were formed and subsequently degraded, although not always completely. Some of these were identified by mass spectral analyses. Among the products, isomers of phenolic and carbonyl derivatives of parent compounds were common to each of the herbicides analyzed. More extensively oxidized products were not detected. Degradation pathways are proposed for each of the parent compounds and identified products.

Magnetic multi-metal co-doped magnesium ferrite nanoparticles: An efficient visible light-assisted heterogeneous Fenton-like catalyst synthesized from saprolite laterite ore.

PubMed

Diao, Yifei; Yan, Zhikai; Guo, Min; Wang, Xidong

2018-02-15

Magnetic nanoparticles of multi-metal co-doped magnesium ferrite (MgFe 2 O 4 ) were synthesized from saprolite laterite ore by a hydrothermal method, and firstly proposed as a heterogeneous photon-Fenton-like catalyst for degradation of Rhodamine B (RhB). The factors that influence the degradation reaction including pH value, the concentration of H 2 O 2 and the amount of catalyst, were systematically investigated. The doped MgFe 2 O 4 exhibited a degradation efficiency up to 96.8%, and the chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiencies about 85.6% and 68.3%, respectively, under visible light illumination for 180min. The high activity is mainly attributed to the high specific surface area of the catalyst and the synergistic interaction between photo-catalytic oxidation and Fenton-like oxidation. Moreover, the catalyst also showed good stability and recycling performance for degrading RhB. After five consecutive degradation cycles, the activity decayed no more than 10%. Compared to other catalysts prepared from pure chemical agents, the multi-metal co-doped MgFe 2 O 4 is more competitive due to its high activity, good stability, ease of recollection, and especially the use of saprolite laterite ore as precursor. This work may provide a new avenue to synthesize efficient ferrite catalysts for degrading organic pollutants in wastewater by using natural minerals. Copyright © 2017 Elsevier B.V. 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.

76 FR 4725 - Apria Healthcare Customer Service Department; Fourteen Locations in Missouri Cameron, Cape...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-26

..., Fenton, Joplin, Lee's Summit, Pleasant Valley, Poplar Bluff, Rolla, Springfield, St. Joseph, St. Peters... in Missouri: Cameron, Cape Girardeau, Columbia, Farmington, Fenton, Joplin, Lee's Summit, Pleasant..., Farmington, Fenton, Joplin, Lee's Summit, Pleasant Valley, Poplar Bluff, Rolla, Springfield, St. Joseph, St...

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.

Evaluation of the efficiency of the photo Fenton disinfection of natural drinking water source during the rainy season in the Sahelian region.

PubMed

Ndounla, J; Pulgarin, C

2014-09-15

The photo-disinfection of water from two different wells (W1, pH: 4.6-5.1 ± 0.02) and (W2 pH: 5.6-5.7 ± 0.02) was carried out during the rainy season at Ouagadougou-Burkina Faso, West Africa. The weather variation during the rainy season significantly affects the photo-disinfection processes (solar disinfection and photo-Fenton). The dilution of the water by rainwater highly affected the chemical composition of the wells' water used in this study; very low iron contents Compared to the ones recorded during the dry season were recorded in all water samples. Both photo-disinfection processes were used to treat 25 L of water in a compound parabolic collector (CPC). None of them have shown the total inactivation of both wild enteric bacteria strains (total coliforms/E. coli and Salmonella spp.) involved in the treatment. However, the total coliforms/E. coli strains were totally inactivated during the exposure under most of the photo-Fenton treatment. Also, the remaining strains, especially those of Salmonella spp. were achieved during the subsequent 24h of dark storage under the action of the Fenton process. Under uniquely solar radiation, total inactivation was recorded only in the total coliforms/E. coli strains. The impact of the available irradiance on the efficiency of the photo-Fenton disinfection of natural water was highlighted during the exposure under high intermittent solar radiation. The impact of the HCO3(-) concentration of both wells' water on the evolution of the pH during the photo-disinfection was recorded. Drastic decrease was noticed after the initial fast increase in presence of low HCO3(-) concentration while a steady state was observed after the increase in presence of higher concentration. The redox activities of the nitrogen components of the water during both photo-disinfection processes have led to increased concentration of nitrite in all the cases and variations were noticed in that of nitrate and ammonia. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

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...

TREATMENT OF MTBE USING FENTON'S REAGENT

EPA Science Inventory

This paper addresses the removal of MTBE from water, using Fenton's Reagent. Although complete mineralization of MTBE by Fenton's Reagent was not achieved, greater than 99% destruction of MTBE was realized. This was accomplished at a Fe+2:H2O2 ratio of 1:1 and one hour of contact...

75 FR 29258 - Proposed Flood Elevation Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-25

... Barker, Town Reach 1. of Chenango, Town of Dickinson, Town of Fenton, Village of Port Dickinson... River. Town of Fenton. Approximately 2.5 miles None +1011 upstream of Ballyhack Road. Page Brook At the confluence with +876 +878 Town of Fenton. the Chenango River. Approximately 630 feet +877 +878 downstream of...

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.

Modified Fe3O4- hydroxyapatite nanocomposites as heterogeneous catalysts in three UV, Vis and Fenton like degradation systems

NASA Astrophysics Data System (ADS)

Valizadeh, S.; Rasoulifard, M. H.; Dorraji, M. S. Seyed

2014-11-01

The magnetite-hydroxyapatite (M-HAP) nanocomposites were prepared by a chemical co- precipitation procedure and characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectra (DRS). The ability of the synthesized catalyst for photocatalytic degradation of Acid Blue 25 (AB25), as an organic dye, under UV irradiation was studied. The catalyst was modified employing transition metals (Mn, Fe, Co, Ni, Cu and Zn) trying to improve the catalytic performance of HAP in absence of UV irradiation and in the presence of hydrogen peroxide i.e. a Fenton like reaction. The best results obtained for Cu and Co modified M-HAPs and the effect of operational parameters such pH, amount of catalyst and hydrogen peroxide concentration was studied. In order to investigate the performance of HAP based photocatalyst in visible light region, M-HAP was modified with silver ions. At the end, Langmuir-Hinshelwood kinetic expression used to evaluate and compare the catalytic systems. The strongest degradation activity was observed for Ag-M-HAP/Vis system because of Ag3PO4 formation. Apparent reaction rate constant (Kapp) by Ag-M-HAP/Vis was 63, 36 and 19 times faster than Cu-M-HAP(II)/H2O2, Co-M-HAP(II)/H2O2 and M-HAP (I)/UV systems, respectively.

Overlapping and Complementary Oxidative Stress Defense Mechanisms in Nontypeable Haemophilus influenzae

PubMed Central

Baker, Beth D.; Munson, Robert S.

2014-01-01

The Gram-negative commensal bacterium nontypeable Haemophilus influenzae (NTHI) can cause respiratory tract diseases that include otitis media, sinusitis, exacerbations of chronic obstructive pulmonary disease, and bronchitis. During colonization and infection, NTHI withstands oxidative stress generated by reactive oxygen species produced endogenously, by the host, and by other copathogens and flora. These reactive oxygen species include superoxide, hydrogen peroxide (H2O2), and hydroxyl radicals, whose killing is amplified by iron via the Fenton reaction. We previously identified genes that encode proteins with putative roles in protection of the NTHI isolate strain 86-028NP against oxidative stress. These include catalase (HktE), peroxiredoxin/glutaredoxin (PgdX), and a ferritin-like protein (Dps). Strains were generated with mutations in hktE, pgdX, and dps. The hktE mutant and a pgdX hktE double mutant were more sensitive than the parent to killing by H2O2. Conversely, the pgdX mutant was more resistant to H2O2 due to increased catalase activity. Supporting the role of killing via the Fenton reaction, binding of iron by Dps significantly mitigated the effect of H2O2-mediated killing. NTHI thus utilizes several effectors to resist oxidative stress, and regulation of free iron is critical to this protection. These mechanisms will be important for successful colonization and infection by this opportunistic human pathogen. PMID:25368297

The Janus face of iron on anoxic worlds: iron oxides are both protective and destructive to life on the early Earth and present-day Mars.

PubMed

Wadsworth, Jennifer; Cockell, Charles S

2017-05-01

The surface of the early Earth was probably subjected to a higher flux of ultraviolet (UV) radiation than today. UV radiation is known to severely damage DNA and other key molecules of life. Using a liquid culture and a rock analogue system, we investigated the interplay of protective and deleterious effects of iron oxides under UV radiation on the viability of the model organism, Bacillus subtilis. In the presence of hydrogen peroxide, there exists a fine balance between iron oxide's protective effects against this radiation and its deleterious effects caused by Photo-Fenton reactions. The maximum damage was caused by a concentration of hematite of ∼1 mg/mL. Concentrations above this confer increasing protection by physical blockage of the UV radiation, concentrations below this cause less effective UV radiation blockage, but also a correspondingly less effective Photo-Fenton reaction, providing an overall advantage. These results show that on anoxic worlds, surface habitability under a high UV flux leaves life precariously poised between the beneficial and deleterious effects of iron oxides. These results have relevance to the Archean Earth, but also the habitability of the Martian surface, where high levels of UV radiation in combination with iron oxides and hydrogen peroxide can be found. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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.

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.

Synthetic bovine proline-rich-polypeptides generate hydroxyl radicals and fail to protect dopaminergic neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopaminergic neurotoxicity in mice.

PubMed

Knaryan, Varduhi H; Samantaray, Supriti; Varghese, Merina; Srinivasan, Ambika; Galoyan, Armen A; Mohanakumar, Kochupurackal P

2006-08-01

Proline-rich-polypeptides (PRPs) isolated from bovine hypothalamus have been shown to render protection against neuronal injury of the brain and spinal cord. We examined two PRPs containing 15 and 10 amino acid residues (PRP-1 and PRP-4 synthetic polypeptide) for their effect, if any, on dopaminergic neuronal damage caused by the parkinsonian neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Effects of these PRPs on hydroxyl radical ((*)OH) generation in a Fenton-like reaction as well as from isolated mitochondria were monitored, employing a sensitive salicylate hydroxylation procedure. Balb/c mice treated (i.p., twice, 16 h apart) with MPTP (30 mg/kg) or PRP-1 (1.6 mg/kg), but not PRP-4 (1.6 mg/kg) showed significant loss of striatal dopamine and norepinephrine as assayed by an HPLC-electrochemical procedure. Pretreatment with the PRPs, 30 min prior to the neurotoxin administration failed to attenuate MPTP-induced striatal dopamine or norepinephrine depletion, but significantly attenuated the MPTP-induced decrease in dopamine turnover. A significant increase in the generation of (*)OH by the PRPs in a Fenton-like reaction or from isolated mitochondria suggests their pro-oxidant action, and explains their failure to protect against MPTP-induced parkinsonism in mice.

Cryptosporidium-contaminated water disinfection by a novel Fenton process.

PubMed

Matavos-Aramyan, Sina; Moussavi, Mohsen; Matavos-Aramyan, Hedieh; Roozkhosh, Sara

2017-05-01

Three novel modified advanced oxidation process systems including ascorbic acid-, pro-oxidants- and ascorbic acid-pro-oxidants-modified Fenton system were utilized to study the disinfection efficiency on Cryptosporidium-contaminated drinking water samples. Different concentrations of divalent and trivalent iron ions, hydrogen peroxide, ascorbic acid and pro-oxidants at different exposure times were investigated. These novel systems were also compared to the classic Fenton system and to the control system which comprised of only hydrogen peroxide. The complete in vitro mechanism of the mentioned modified Fenton systems are also provided. The results pointed out that by considering the optimal parameter limitations, the ascorbic acid-modified Fenton system decreased the Cryptosporidium oocytes viability to 3.91%, while the pro-oxidant-modified and ascorbic acid-pro-oxidant-modified Fenton system achieved an oocytes viability equal to 1.66% and 0%, respectively. The efficiency of the classic Fenton at optimal condition was observed to be 20.12% of oocytes viability. The control system achieved 86.14% of oocytes viability. The optimum values of the operational parameters during this study are found to be 80mgL -1 for the divalent iron, 30mgL -1 for ascorbic acid, 30mmol for hydrogen peroxide, 25mgL -1 for pro-oxidants and an exposure time equal to 5min. The ascorbic acid-pro-oxidants-modified Fenton system achieved a promising complete water disinfection (0% viability) at the optimal conditions, leaving this method a feasible process for water disinfection or decontamination, even at industrial scales. Copyright © 2017 Elsevier Inc. All rights reserved.

Response to Fenton and Fenton: evidence does not support the alkaline diet

USDA-ARS?s Scientific Manuscript database

In the space available in this broad review, we focused on large trials published since the 2011 Fenton meta-analysis. This included two trials published in 2013 and one in 2015. These trials found favorable effects of supplementation with alkaline salts of potassium, in amounts of 60 mmol/day and h...

75 FR 20384 - Chrysler LLC, St. Louis North Assembly Plant, Including On-Site Leased Workers From Haas TCM, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-19

.... Diversified Contract Service, Inc. 639, and Logistics Management Services, Inc. Fenton, MO; Amended..., 2008, applicable to workers of Chrysler LLC, St. Louis North Assembly Plant, Fenton, Missouri. The... Logistics Management Services, Inc. worked on-site at the Chrysler LLC, Fenton, Missouri plant (Logistics...

75 FR 20382 - Chrysler LLC, St. Louis North Assembly Plant, Including On-Site Leased Workers From HAAS TCM, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-19

...., Diversified Contract Service, Inc. 639, and Logistics Management Services, Inc., Fenton, MO; Amended..., 2008, applicable to workers of Chrysler LLC, St. Louis North Assembly Plant, Fenton, Missouri. The... Logistics Management Services, Inc. worked on-site at the Chrysler LLC, Fenton, Missouri plant (Logistics...

75 FR 28654 - Chrysler LLC; St. Louis North Assembly Plant, Including On-Site Leased Workers From HAAS TCM, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

...., Robinson Solutions, and Yazaki North America; Fenton, MO; Amended Certification Regarding Eligibility To... Chrysler LLC, St. Louis North Assembly Plant, Fenton, Missouri. The notice was published in the Federal... Fenton, Missouri location of Chrysler LLC, St. Louis North Assembly Plant. The Department has determined...

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.

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.

Hot dry rock geothermal energy development program. Semiannual report, October 1, 1978-March 31, 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, M.C.; Nunz, G.J.; Cremer, G.M.

1979-09-01

The potential of energy extracted from hot dry rock (HDR) was investigated as a commercailly feasible alternate energy source. Run Segments 3 and 4 were completed in the prototype reservoir of the Phase I energy-extraction system at Fenton Hill, New Mexico. Results of these tests yielded significant data on the existing system and this information will be applicable to future HDR systems. Plans and operations initiating a Phase II system are underway at the Fenton Hill site. This system, a deeper, hotter commercial-size reservoir, is intended to demonstrate the longevity and economics of an HDR system. Major activity occurred inmore » evaluation of the national resource potential and in characterizing possible future HDR geothermal sites. Work has begun in the institutional and industrial support area to assess the economics and promote commercial interest in HDR systems as an alternate energy source.« less

Preparation of zeolite nanorods by corona discharge plasma for degradation of phenazopyridine by heterogeneous sono-Fenton-like process.

PubMed

Khataee, Alireza; Rad, Tannaz Sadeghi; Vahid, Behrouz; Khorram, Sirous

2016-11-01

The plasma-modified clinoptilolite (PMC) nanorods were prepared from natural clinoptilolite (NC) utilizing environmentally-friendly corona discharge plasma. The PMC and NC were characterized by XRD, FT-IR, SEM, EDX, XPS and BET, which confirmed the nanocatalyst formation. The catalytic performance of the PMC in the heterogeneous sono-Fenton-like process was greater than the NC for treatment of phenazopyridine (PhP). The desired amounts were obtained for experimental parameters including initial pH (5), PMC dosage (2g/L), K2S2O8 concentration (2mmol/L), ultrasonic power (300W) and PhP concentration (10mg/L). Reactive oxygen species scavengers decreased the removal efficiency of the PhP. The treatment process followed pseudo-first order kinetic and seven degradation intermediates were identified by the GC-MS technique. Copyright © 2016 Elsevier B.V. All rights reserved.

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).

Colliding-Droplet Microreactor: Rapid On-Demand Inertial Mixing and Metal-Catalyzed Aqueous Phase Oxidation Processes.

PubMed

Davis, Ryan D; Jacobs, Michael I; Houle, Frances A; Wilson, Kevin R

2017-11-21

In-depth investigations of the kinetics of aqueous chemistry occurring in microdroplet environments require experimental techniques that allow a reaction to be initiated at a well-defined point in time and space. Merging microdroplets of different reactants is one such approach. The mixing dynamics of unconfined (airborne) microdroplets have yet to be studied in detail, which is an essential step toward widespread use and application of merged droplet microreactors for monitoring chemical reactions. Here, we present an on-demand experimental approach for initiating chemical reactions in and characterizing the mixing dynamics of colliding airborne microdroplets (40 ± 5 μm diameter) using a streak-based fluorescence microscopy technique. The advantages of this approach include the ability to generate two well-controlled monodisperse microdroplet streams and collide (and thus mix) the microdroplets with high spatial and temporal control while consuming small amounts of sample (<0.1 μL/s). Mixing times are influenced not only by the velocity at which microdroplets collide but also the geometry of the collision (i.e., head-on vs off-center collision). For head-on collisions, we achieve submillisecond mixing times ranging from ∼900 μs at a collision velocity of 0.1 m/s to <200 μs at ∼6 m/s. For low-velocity (<1 m/s) off-center collisions, mixing times were consistent with the head-on cases. For high-velocity (i.e., > 1 m/s) off-center collisions, mixing times increased by as much as a factor of 6 (e.g., at ∼6 m/s, mixing times increased from <200 μs for head-on collisions to ∼1200 μs for highly off-center collisions). At collision velocities >7 m/s, droplet separation and fragmentation occurred, resulting in incomplete mixing. These results suggest a limited range of collision velocities over which complete and rapid mixing can be achieved when using airborne merged microdroplets to, e.g., study reaction kinetics when reaction times are short relative to typical bulk reactor mixing times. We benchmark our reactor using an aqueous-phase oxidation reaction: iron-catalyzed hydroxyl radical production from hydrogen peroxide (Fenton's reaction) and subsequent aqueous-phase oxidation of organic species in solution. Kinetic simulations of our measurements show that quantitative agreement can be obtained using known bulk-phase kinetics for bimolecular reactions in our colliding-droplet microreactor.

Colliding-Droplet Microreactor: Rapid On-Demand Inertial Mixing and Metal-Catalyzed Aqueous Phase Oxidation Processes

DOE PAGES

Davis, Ryan D.; Jacobs, Michael I.; Houle, Frances A.; ...

2017-10-30

In-depth investigations of the kinetics of aqueous chemistry occurring in microdroplet environments require experimental techniques that allow a reaction to be initiated at a well-defined point in time and space. Merging microdroplets of different reactants is one such approach. The mixing dynamics of unconfined (airborne) microdroplets have yet to be studied in detail, which is an essential step toward widespread use and application of merged droplet microreactors for monitoring chemical reactions. Here, we present an on-demand experimental approach for initiating chemical reactions in and characterizing the mixing dynamics of colliding airborne microdroplets (40 ± 5 μm diameter) using a streak-basedmore » fluorescence microscopy technique. The advantages of this approach include the ability to generate two well-controlled monodisperse microdroplet streams and collide (and thus mix) the microdroplets with high spatial and temporal control while consuming small amounts of sample (<0.1 μL/s). Mixing times are influenced not only by the velocity at which microdroplets collide but also the geometry of the collision (i.e., head-on vs off-center collision). For head-on collisions, we achieve submillisecond mixing times ranging from ~900 μs at a collision velocity of 0.1 m/s to <200 μs at ~6 m/s. For low-velocity (<1 m/s) off-center collisions, mixing times were consistent with the head-on cases. For high-velocity (i.e., > 1 m/s) off-center collisions, mixing times increased by as much as a factor of 6 (e.g., at ~6 m/s, mixing times increased from <200 μs for head-on collisions to ~1200 μs for highly off-center collisions). At collision velocities >7 m/s, droplet separation and fragmentation occurred, resulting in incomplete mixing. These results suggest a limited range of collision velocities over which complete and rapid mixing can be achieved when using airborne merged microdroplets to, e.g., study reaction kinetics when reaction times are short relative to typical bulk reactor mixing times. We benchmark our reactor using an aqueous-phase oxidation reaction: iron-catalyzed hydroxyl radical production from hydrogen peroxide (Fenton's reaction) and subsequent aqueous-phase oxidation of organic species in solution. In conclusion, kinetic simulations of our measurements show that quantitative agreement can be obtained using known bulk-phase kinetics for bimolecular reactions in our colliding-droplet microreactor.« less

Colliding-Droplet Microreactor: Rapid On-Demand Inertial Mixing and Metal-Catalyzed Aqueous Phase Oxidation Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Ryan D.; Jacobs, Michael I.; Houle, Frances A.

In-depth investigations of the kinetics of aqueous chemistry occurring in microdroplet environments require experimental techniques that allow a reaction to be initiated at a well-defined point in time and space. Merging microdroplets of different reactants is one such approach. The mixing dynamics of unconfined (airborne) microdroplets have yet to be studied in detail, which is an essential step toward widespread use and application of merged droplet microreactors for monitoring chemical reactions. Here, we present an on-demand experimental approach for initiating chemical reactions in and characterizing the mixing dynamics of colliding airborne microdroplets (40 ± 5 μm diameter) using a streak-basedmore » fluorescence microscopy technique. The advantages of this approach include the ability to generate two well-controlled monodisperse microdroplet streams and collide (and thus mix) the microdroplets with high spatial and temporal control while consuming small amounts of sample (<0.1 μL/s). Mixing times are influenced not only by the velocity at which microdroplets collide but also the geometry of the collision (i.e., head-on vs off-center collision). For head-on collisions, we achieve submillisecond mixing times ranging from ~900 μs at a collision velocity of 0.1 m/s to <200 μs at ~6 m/s. For low-velocity (<1 m/s) off-center collisions, mixing times were consistent with the head-on cases. For high-velocity (i.e., > 1 m/s) off-center collisions, mixing times increased by as much as a factor of 6 (e.g., at ~6 m/s, mixing times increased from <200 μs for head-on collisions to ~1200 μs for highly off-center collisions). At collision velocities >7 m/s, droplet separation and fragmentation occurred, resulting in incomplete mixing. These results suggest a limited range of collision velocities over which complete and rapid mixing can be achieved when using airborne merged microdroplets to, e.g., study reaction kinetics when reaction times are short relative to typical bulk reactor mixing times. We benchmark our reactor using an aqueous-phase oxidation reaction: iron-catalyzed hydroxyl radical production from hydrogen peroxide (Fenton's reaction) and subsequent aqueous-phase oxidation of organic species in solution. In conclusion, kinetic simulations of our measurements show that quantitative agreement can be obtained using known bulk-phase kinetics for bimolecular reactions in our colliding-droplet microreactor.« less

Ascorbic acid/Fe@Fe2O3: A highly efficient combined Fenton reagent to remove organic contaminants.

PubMed

Hou, Xiaojing; Huang, Xiaopeng; Ai, Zhihui; Zhao, Jincai; Zhang, Lizhi

2016-06-05

In this study, we demonstrate that the combination of ascorbic acid and Fe@Fe2O3 core-shell nanowires (AA/Fe@Fe2O3) offers a highly efficient Fenton reagent. This combined Fenton reagent exhibited extremely high activity on the decomposition of H2O2 to produce OH for the degradation of various organic contaminants, including rhodamine B, methylene blue, alachlor, atrazine, siduron, lincomycin, and chloroamphenicol. The contaminant degradation constants in the AA/Fe@Fe2O3/H2O2 Fenton systems were 38-53 times higher than those in the conventional homogeneous Fenton system (Fe(II)/H2O2) at pH 3.8. Moreover, the OH generation rate constant in the AA/Fe@Fe2O3/H2O2 Fenton system was 1-3 orders of magnitudes greater than those of heterogeneous Fenton systems developed with other iron-containing materials (α-FeOOH, α-Fe2O3, FeOCl, and so on). The high activity of AA/Fe@Fe2O3 was attributed to the effective Fe(III)/Fe(II) cycle and the iron-ascorbate complex formation to stabilize ferrous ions with desirable and steady concentrations. During the AA/Fe@Fe2O3/H2O2 Fenton process, ascorbic acid served as a reducing and complexing reagent, enabling the reuse of Fe@Fe2O3 nanowires. We systematically investigated the alachlor and ascorbic acid degradation and found that they could be effectively degraded in the AA/Fe@Fe2O3/H2O2 system, accompanying with 100% of dechlorination and 92% of denitrification. This study sheds light on the importance of Fe(III)/Fe(II) cycle for the design of high efficient Fenton system and provides an alternative pathway for the organic contaminants removal. Copyright © 2016 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.

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.

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...

75 FR 22627 - Chrysler LLC, St. Louis South Assembly Division, Including On-Site Leased Workers From HAAS TCM...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-29

..., Corrigan Company, and Murphy Company, Fenton, MO; Amended Certification Regarding Eligibility To Apply for... of Chrysler LLC, St. Louis South Assembly Division, Fenton, Missouri. The notice was published in the... employed on-site by the Fenton, Missouri location of Chrysler LLC, St. Louis South Assembly Division. The...

75 FR 22627 - Chrysler LLC, St. Louis North Assembly Plant Including On-Site Leased Workers From HAAS TCM, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-29

...., Robinson Solutions, Logistics Management Services, Inc., Corrigan Company and Murphy Company, Fenton, MO... Plant, Fenton, Missouri. The notice was published in the Federal Register on May 2, 2008 (73 FR 24317... leased from Corrigan Company and Murphy Company were employed on-site at the Fenton, Missouri location of...