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Sample records for methylene blue degradation

  1. Degradation of methylene blue by radio frequency plasmas in water under ultraviolet irradiation.

    PubMed

    Maehara, Tsunehiro; Nishiyama, Kyohei; Onishi, Shingo; Mukasa, Shinobu; Toyota, Hiromichi; Kuramoto, Makoto; Nomura, Shinfuku; Kawashima, Ayato

    2010-02-15

    The degradation of methylene blue by radio frequency (RF) plasmas in water under ultraviolet (UV) irradiation was studied experimentally. When the methylene blue solution was exposed to RF plasma, UV irradiation from a mercury vapor lamp enhanced degradation significantly. A lamp without power supply also enhanced degradation since weak UV light was emitted weakly from the lamp due to the excitation of mercury vapor by stray RF power. Such an enhancement is explained by the fact that after hydrogen peroxide is produced via the recombination process of OH radicals around the plasma, OH radicals reproduced from hydrogen peroxide via the photolysis process degrade methylene blue.

  2. Degradation of methylene blue using biologically synthesized silver nanoparticles.

    PubMed

    Vanaja, M; Paulkumar, K; Baburaja, M; Rajeshkumar, S; Gnanajobitha, G; Malarkodi, C; Sivakavinesan, M; Annadurai, G

    2014-01-01

    Nowadays plant mediated synthesis of nanoparticles has great interest and achievement due to its eco-benign and low time consuming properties. In this study silver nanoparticles were successfully synthesized by using Morinda tinctoria leaf extract under different pH. The aqueous leaf extract was added to silver nitrate solution; the color of the reaction medium was changed from pale yellow to brown and that indicates reduction of silver ions to silver nanoparticles. Thus synthesized silver nanoparticles were characterized by UV-Vis spectrophotometer. Dispersity and morphology was characterized by scanning electron microscope (SEM); crystalline nature and purity of synthesized silver nanoparticles were revealed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). FTIR spectrum was examined to identify the effective functional molecules responsible for the reduction and stabilization of silver nanoparticles synthesized by leaf extract. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Green synthesized silver nanoparticles were effectively degrading the dye nearly 95% at 72 h of exposure time.

  3. Degradation of Methylene Blue Using Biologically Synthesized Silver Nanoparticles

    PubMed Central

    Vanaja, M.; Paulkumar, K.; Baburaja, M.; Rajeshkumar, S.; Gnanajobitha, G.; Malarkodi, C.; Sivakavinesan, M.; Annadurai, G.

    2014-01-01

    Nowadays plant mediated synthesis of nanoparticles has great interest and achievement due to its eco-benign and low time consuming properties. In this study silver nanoparticles were successfully synthesized by using Morinda tinctoria leaf extract under different pH. The aqueous leaf extract was added to silver nitrate solution; the color of the reaction medium was changed from pale yellow to brown and that indicates reduction of silver ions to silver nanoparticles. Thus synthesized silver nanoparticles were characterized by UV-Vis spectrophotometer. Dispersity and morphology was characterized by scanning electron microscope (SEM); crystalline nature and purity of synthesized silver nanoparticles were revealed by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). FTIR spectrum was examined to identify the effective functional molecules responsible for the reduction and stabilization of silver nanoparticles synthesized by leaf extract. The photocatalytic activity of the synthesized silver nanoparticles was examined by degradation of methylene blue under sunlight irradiation. Green synthesized silver nanoparticles were effectively degrading the dye nearly 95% at 72 h of exposure time. PMID:24772055

  4. [Research on degradation of methylene blue by coal bottom ash-microwave irradiation method].

    PubMed

    Wu, Shi-Wei; Li, Na; Li, Guang-Zhe; Li, Guo-De

    2010-05-01

    Coal bottom ash is rich in metals and transition metals, and with microwave irradiation these metals can effectively degradate organic matter. Methylene blue degradation by coal bottom ash-microwave irradiation mainly through hydroxyl radicals to degrade organic matter, and metals and rare metals in bottom ash can be used as a catalyst for deep oxidation of organic matter, can reduce processing costs, and reduce environmental pollution. In the present paper the main parameters including the amount of coal bottom ash, H2O2 dosage and time of microwave irradiation were investigated. The UV-visible spectra of methylene blue were determined. The results show that: under coal bottom ash and H2O2 microwave condition the degeneration rate of methylene blue was almost 100%. The dosage of coal ash can accelerate the reaction process, speeding up the degradation of methylene blue. The increase of H2O2 may provide more * OH and speed up the reaction process, but when up to a certain amount, the influence is weakened. The lengthening of microwave time may enhance the reaction temperature, and urge the methylene blue to degrade completely. For 0.125 g x L(-1) of methylene blue, by adding 1.0 g coal bottom ash, 5 mL H2O2 and under mesotherm microwave temperature for 4 min, the methylene blue can be all degradated.

  5. Sonocatalytic degradation of methylene blue with TiO2 pellets in water.

    PubMed

    Shimizu, Nobuaki; Ogino, Chiaki; Dadjour, Mahmoud Farshbaf; Murata, Tomoyuki

    2007-02-01

    A series of experiments were carried out to study the degradation of methylene blue by the irradiation of ultrasound onto TiO(2) in aqueous solution. A statistically significant decrease in the concentration of methylene blue was observed after 60 min irradiation. While the reduction was 22% of the initial concentration without H(2)O(2), addition of H(2)O(2) significantly enhanced the degradation of methylene blue for the TiO(2) containing system (85% reduction of the initial concentration). The addition of H(2)O(2) had no effect on the methylene blue degradation when the system contained Al(2)O(3). The degradation ratio of methylene blue was dependent on the amount of TiO(2) and also the specific surface area of TiO(2) in the solution. The effects of radical scavenging agents on the degradation of methylene blue were also investigated for the system with TiO(2). It was found that the radical scavenging agents dimethyl sulfoxide (DMSO), methanol, and mannitol suppressed the degradation, with DMSO being the most effective. The effect of pH on the degradation of methylene blue was further investigated. An U-shaped change in the concentration of methylene blue in the presence of TiO(2) was observed along with the change in pH values (pH 3-12), and the highest degradation ratio was observed at around pH 7. In conclusion, ultrasound irradiation of TiO(2) in aqueous solution resulted in significant generation of hydroxyl radicals, and this process may have potential for the treatment of organic dyes in wastewater.

  6. Effect of dimethyl sulfoxide addition on ultrasonic degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Shimakage, Kaho; Kobayashi, Daisuke; Naya, Masakazu; Matsumoto, Hideyuki; Shimada, Yuichiro; Otake, Katsuto; Shono, Atsushi

    2016-07-01

    The ultrasonic degradation of methylene blue was carried out in the absence and presence of dimethyl sulfoxide (DMSO) as a radical scavenger for various frequencies, and the effects of DMSO addition on the degradation rate constant estimated by assuming first-order kinetics were investigated. The degradation reaction rate decreased with DMSO addition, and hydroxyl radicals were observed to play important roles in the degradation of methylene blue. However, the degradation reaction did not stop with DMSO addition, and the degradation rate constant in the presence of DMSO was not affected by ultrasonic frequency.

  7. Fast photocatalytic degradation of methylene blue dye using a low-power diode laser.

    PubMed

    Liu, Xianhua; Yang, Yulou; Shi, Xiaoxuan; Li, Kexun

    2015-01-01

    This study focused on the application of diode lasers as alternative light sources for the fast photocatalytic degradation of methylene blue. The photocatalytic decomposition of methylene blue in aqueous solution under 443 nm laser light irradiation was found to be technically feasible using Ag/AgCl nanoparticles as photocatalysts. The effects of various experimental parameters, such as irradiation time, light source, catalyst loading, initial dye concentration, pH, and laser energy on decolorization and degradation were investigated. The mineralization of methylene blue was confirmed by chemical oxygen demand analysis. The results demonstrate that the laser-induced photocatalytic process can effectively degrade methylene blue under the optimum conditions (pH 9.63, 4 mg/L MB concentration, and 1.4 g/L Ag/AgCl nanoparticles).

  8. Feasibility study of photoelectrochemical degradation of methylene blue with three-dimensional electrode-photocatalytic reactor.

    PubMed

    An, Tai-Cheng; Zhu, Xi-Hai; Xiong, Ya

    2002-02-01

    The photoelectrochemical degradation of methylene blue in aqueous solution was investigated with three-dimensional electrode-photocatalytic reactor. It was found that the methylene blue could be degraded more efficiently by photoelectrochemical process than by photocatalytic oxidation or electrochemical oxidation alone. The decolorization efficiency and COD reduction were 95% and 87% for a photoelectrochemical process, respectively, while they were only 78% and 68% for a single electrochemical process and 89% and 71% for a single photochemical process. The TOC reduction of the former also reached as high as about 81% within a reaction time of 30.0 min. And these degradation reactions conformed to pseudo-first-order kinetics.

  9. Synthesis of mesoporous TiO2-curcumin nanoparticles for photocatalytic degradation of methylene blue dye.

    PubMed

    Abou-Gamra, Z M; Ahmed, M A

    2016-07-01

    Herein, we demonstrate a facile route for synthesis a new photocatalyst based on TiO2-curcumin nanoparticles for photodegradation of methylene blue dye under UV and visible light irradiation. The photocatalyst was prepared by sol-gel method using chitosan as biodegradable polymer. The crystalline and the nanostructure were characteristic X-ray diffraction [XRD], adsorption-desorption isotherm and high resolution transmission electron microscopy [HRTEM]. However, the optical features of the samples were investigated by a UV-visible spectrophotometer. It is obvious to notice the removal of the majority of methylene blue dye on a pure titania surface via adsorption mechanism owing to the high surface area and to the organized mesoporous nature of the solid sample. Incorporation of curcumin on titania surface changes the removal direction from adsorption to the photocatalytic pathway. Various photocatalytic experiments were performed to investigate the influence of initial dye concentration, weight of catalyst, stirring and light intensity on the photocatalytic degradation of methylene blue as primary pollutant model. Chemical oxygen demand [COD] test confirms the complete degradation of methylene blue dye. The exceptional photocatalytic reactivity of titania-curcumin nanoparticles is referred to reduction in band gap energy and to the facility of electron transfer from II* curcumin energy level to titania conduction band which increases the concentration of reactive oxygen superoxide radicals which in turn prevents the electron-hole recombination. The effect of various scavengers on the methylene blue dye degradation was investigated using ethanol, ascorbic acid and methyl viologen. The results have pointed out that O2(-) and HO(.) are considered the main active species in the degradation process. A plausible pathway and mechanism for the photocatalytic degradation of methylene blue by titania-curcumin nanoparticles were illustrated.

  10. Photocatalytic degradation of methylene blue with a nanocomposite system: synthesis, photocatalysis and degradation pathways.

    PubMed

    Xia, Shengjie; Zhang, Lianyang; Pan, Guoxiang; Qian, Pingping; Ni, Zheming

    2015-02-21

    Three different composites, including a calcined FeOOH supported ZnAl layered double hydroxide (FeOOH-LDO), a calcined ZnAl layered double hydroxide (ZnAl-LDO) and a calcined ZnFeAl layered double hydroxide (ZnFeAl-LDO), were synthesized via a sol-gel method, and their activity for the visible light photocatalytic degradation of methylene blue (MB) was studied. The composites were characterized by PXRD, SEM, and BET techniques, confirming the formation of highly crystalline structures. The activity performance of MB degradation was in the following order: FeOOH-LDO (∼95%) > ZnFeAl-LDO (∼60%) > ZnAl-LDO (∼23%). In addition, a possible photocatalytic degradation reaction mechanism for MB was also proposed. Moreover, the frontier electron densities on the atoms of MB were calculated, which were in satisfactory agreement with the postulated mechanism.

  11. Catalytic liquid marbles: Ag nanowire-based miniature reactors for highly efficient degradation of methylene blue.

    PubMed

    Miao, Yue-E; Lee, Hiang Kwee; Chew, Wee Shern; Phang, In Yee; Liu, Tianxi; Ling, Xing Yi

    2014-06-04

    Ag nanowire-based catalytic liquid marbles are fabricated as miniature reactors, which demonstrate highly efficient, support-free and rate-controllable heterogeneous degradation of methylene blue, with catalytic efficiency close to 100%. Our miniature catalytic liquid marbles are essential for reactions involving highly toxic/hazardous or costly reactants, where small volume preliminary reactions are preferred.

  12. Functional elastic hydrogel as recyclable membrane for the adsorption and degradation of methylene blue.

    PubMed

    Bao, Song; Wu, Dongbei; Wang, Qigang; Su, Teng

    2014-01-01

    Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young's modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g(-1). The hydrogel also exhibited higher separation selectivity to Pb(2+) than Cu(2+). The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables.

  13. Functional Elastic Hydrogel as Recyclable Membrane for the Adsorption and Degradation of Methylene Blue

    PubMed Central

    Bao, Song; Wu, Dongbei; Wang, Qigang; Su, Teng

    2014-01-01

    Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young’s modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g−1. The hydrogel also exhibited higher separation selectivity to Pb2+ than Cu2+. The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables. PMID:24586396

  14. Kinetics analysis for development of a rate constant estimation model for ultrasonic degradation reaction of methylene blue.

    PubMed

    Kobayashi, Daisuke; Honma, Chiemi; Matsumoto, Hideyuki; Takahashi, Tomoki; Kuroda, Chiaki; Otake, Katsuto; Shono, Atsushi

    2014-07-01

    Ultrasound has been used as an advanced oxidation method for wastewater treatment. Sonochemical degradation of organic compounds in aqueous solution occurs by pyrolysis and/or reaction with hydroxyl radicals. Moreover, kinetics of sonochemical degradation has been proposed. However, the effect of ultrasonic frequency on degradation rate has not been investigated. In our previous study, a simple model for estimating the apparent degradation rate of methylene blue was proposed. In this study, sonochemical degradation of methylene blue was performed at various frequencies. Apparent degradation rate constant was evaluated assuming that sonochemical degradation of methylene blue was a first-order reaction. Specifically, we focused on effects of ultrasonic frequency and power on rate constant, and the applicability of our proposed model was demonstrated. Using this approach, maximum sonochemical degradation rate was observed at 490 kHz, which agrees with a previous investigation into the effect of frequency on the sonochemical efficiency value evaluated by KI oxidation dosimetry. Degradation rate increased with ultrasonic power at every frequency. It was also observed that threshold power must be reached for the degradation reaction to progress. The initial methylene blue concentration and the apparent degradation rate constant have a relation of an inverse proportion. Our proposed model for estimating the apparent degradation rate constant using ultrasonic power and sonochemical efficiency value can apply to this study which extended the frequency and initial concentration range.

  15. Enhanced photocatalytic degradation of methylene blue on multiwalled carbon nanotubes-TiO2.

    PubMed

    Zhao, Donglin; Yang, Xin; Chen, Changlun; Wang, Xiangke

    2013-05-15

    A visible-light photocatalyst of multiwalled carbon nanotubes decorated with TiO2 nanoparticles (MWCNT/TiO2) was synthesized by a two-step method, in which TiO2 was first mounted on MWCNT surfaces by hydrolysis of tetrabutyl titanate and further crystallized into anatase nanocrystal in a vacuum furnace at 500°C. The photocatalytic degradation of methylene blue over the ultraviolet (UV) and visible-light spectrum regions was investigated. The MWCNT/TiO2 was able to absorb a high amount of photo energy in the visible-light region, driving effectively photochemical degradation reactions. There were more OH radicals produced by the MWCNT/TiO2 (1:3) than by pure TiO2 under UV and visible-light irradiation. In the photodegradation of methylene blue, as a model reaction, a signification enhancement in the reaction rate was observed with the MWCNT/TiO2 (1:3), compared to bare TiO2 and the physical mixture of MWCNTs and TiO2. MWCNTs can improve the photocatalytic activity of TiO2 in two aspects, namely e(-) transportation and adsorption. This work provides new insight into the fabrication of MWCNT/TiO2 as a high performance visible-light photocatalyst and facilitates its application in photocatalytic degradation of organic compounds.

  16. Adsorptional photocatalytic degradation of methylene blue onto pectin-CuS nanocomposite under solar light.

    PubMed

    Gupta, Vinod Kumar; Pathania, Deepak; Agarwal, Shilpi; Singh, Pardeep

    2012-12-01

    This study describes the effect of adsorption on methylene blue degradation using pectin-CuS nanocomposite (PCSNC). The nanocomposite was synthesized using co-precipitation methods followed by direct encapsulation with pectin. The synthesized nanocomposite was characterized by SEM, TEM, XRD, FTIR and UV-vis spectral technique. The adsorption and photocatalytic efficiencies of PCSNC were compared with copper sulphide nanoparticle (CSNP). The dye removal was studied under different reaction conditions. The adsorption capacity of pectin based nanocomposite was higher due to other free functional group on pectin surface after connecting to nanoparticles. The simultaneous adsorption and photodegradation process (A+P) was the most efficient process due to rapid destruction of adsorbed dye molecules. The complete COD removal was attained in 10h using PCSNC/A+P process. On comparing with CSNP, pectin-CuS nano composite showed more degradation efficiency and reusability for MB degradation.

  17. Efficacy of SnO2 nanoparticles toward photocatalytic degradation of methylene blue dye.

    PubMed

    Elango, Ganesh; Roopan, Selvaraj Mohana

    2016-02-01

    Maximum pollutants in the industrial and domestic waste water effluents from any sources include pathogens and organic chemicals, which can be removed before discharging into the water bodies. Methylene blue has been considered as one of the major water contaminated pollutants. Such pollutant is dominant in surface water and groundwater. It will cause irreversible hazards to human and aquatic life. Nanotechnology plays a major role in degrading such type of pollutant. In order to fulfill today's requirement, we have decided to handle the green synthesis of nanoparticles and its application by merging important fields like chemistry, environmental science, and biotechnology. Here our work emphasizes on the biological synthesis of SnO2 nanoparticles (SnO2 NPs) using the methanolic extract of Cyphomandra betacea (C.betacea), and it was confirmed by various characterization techniques such as UV-visible spectroscopy, FT-IR, XRD, SEM, particle size analyzer, zeta potential, and TEM. The obtained results stated that the synthesized SnO2 NPs were in rod shape with an average size of 21nm, which resulted in a product of nanobiotechnology. Further, we have utilized the environmental-friendly synthesized SnO2 NPs photocatalytic degradation of environmental concern methylene blue with first-order kinetics. In this paper, we have attempted to prove that secondary metabolite-entrapped SnO2 NPs are non-toxic to the environment.

  18. Enhanced photocatalytic degradation of methylene blue by metal-modified silicon nanowires

    SciTech Connect

    Brahiti, N.; Hadjersi, T.; Menari, H.; Amirouche, S.; El Kechai, O.

    2015-02-15

    Highlights: • SiNWs modified with Pd, Au and Pt were used as photocatalysts to degrade MB. • Yield of photodegardation increases with UV irradiation time. • SiNWs modified with Pd nanoparticles show the best photocatalytic activity. • A degradation of 97% was obtained after 200 min of UV irradiation. - Abstract: Silicon nanowires (SiNWs) modified with Au, Pt and Pd nanoparticles were used as heterogeneous photocatalysts for the photodegradation of methylene blue in water under UV light irradiation. The modification of SiNWs was carried out by deposition of metal nanoparticles using the electroless metal deposition (EMD) technique. The effect of metal nanoparticles deposition time on the photocatalytic activity was studied. It was found that the photocatalytic activity of modified SiNWs was enhanced when the deposition time of metal nanoparticles was increased. In addition of modified SiNWs with Pt, Au and Pd nanoparticles, oxidized silicon substrate (Ox-Si), oxidized silicon nanowires (Ox-SiNWs) and hydrogen-terminated silicon nanowires (H-SiNWs) were also evaluated for the photodegradation of methylene blue.

  19. Methylene blue test

    MedlinePlus

    Methemoglobinemia - methylene blue test ... No special preparation is required for this test. ... which are genetic (problem with your genes). This test is used to tell the difference between methemoglobinemia ...

  20. Photocatalytic degradation of methylene blue dye under visible light over Cr doped strontium titanate (SrTiO3) nanoparticles.

    PubMed

    Qazi, Inamur Rahman; Lee, Woo-Jin; Lee, Hyun-Cheol; Hassan, Mallick Shamshi; Yang, O-Bong

    2010-05-01

    Strontium titanate (SrTiO3) and chromium doped SrTiO3 (Cr/SrTiO3) were prepared by modified sol-gel method with the citric acid as a chelating agent in the ethylene glycol solution for the effective photodegradation of methylene blue dye under visible light irradiation. The synthesized doped and un-doped SrTiO3 nanoparticles were structurally characterized and their photoresponse performances for the efficient degradation of methylene blue dye have been demonstrated. After introducing the Cr on SrTiO3, UV-Vis absorption was appeared the red-shift at 566 nm from 392 nm as compare with bare SrTiO3. The photocatalytic degradation activity of Cr/SrTiO3 was significantly improved to 60% degradation of methylene blue in 3 h under visible light, which is approximately 5 times higher than that of the bare SrTiO3.

  1. Laser-Induced Silver Nanoparticles on Titanium Oxide for Photocatalytic Degradation of Methylene Blue

    PubMed Central

    Whang, Thou-Jen; Huang, Hsien-Yu; Hsieh, Mu-Tao; Chen, Jyun-Jen

    2009-01-01

    Silver nanoparticles doped on titanium oxide (TiO2) were produced by laser-liquid interaction of silver nitrate (AgNO3) in isopropanol. Characteristics of Ag/TiO2 (Ag doped TiO2) nanoparticles produced by the methods presented in this article were investigated by XRD, TEM, SEM, EDX, and UV-Vis. From the UV-Vis measurements, the absorption of visible light of the Ag/TiO2 photocatalysts was improved (additional absorption at longer wavelength in visible light region) obviously. The photocatalytic efficiency of Ag/TiO2 was tested by the degradation of methylene blue (MB) in aqueous solution. A maximum of 82.3% MB degradation is achieved by 2.0 wt% Ag/TiO2 photocatalyst under 2 h illumination with a halogen lamp. PMID:20087459

  2. Laser-induced silver nanoparticles on titanium oxide for photocatalytic degradation of methylene blue.

    PubMed

    Whang, Thou-Jen; Huang, Hsien-Yu; Hsieh, Mu-Tao; Chen, Jyun-Jen

    2009-10-29

    Silver nanoparticles doped on titanium oxide (TiO(2)) were produced by laser-liquid interaction of silver nitrate (AgNO(3)) in isopropanol. Characteristics of Ag/TiO(2) (Ag doped TiO(2)) nanoparticles produced by the methods presented in this article were investigated by XRD, TEM, SEM, EDX, and UV-Vis. From the UV-Vis measurements, the absorption of visible light of the Ag/TiO(2) photocatalysts was improved (additional absorption at longer wavelength in visible light region) obviously. The photocatalytic efficiency of Ag/TiO(2) was tested by the degradation of methylene blue (MB) in aqueous solution. A maximum of 82.3% MB degradation is achieved by 2.0 wt% Ag/TiO(2) photocatalyst under 2 h illumination with a halogen lamp.

  3. Inhibition of hsp70 by methylene blue affects signaling protein function and ubiquitination and modulates polyglutamine protein degradation.

    PubMed

    Wang, Adrienne M; Morishima, Yoshihiro; Clapp, Kelly M; Peng, Hwei-Ming; Pratt, William B; Gestwicki, Jason E; Osawa, Yoichi; Lieberman, Andrew P

    2010-05-21

    The Hsp90/Hsp70-based chaperone machinery regulates the activity and degradation of many signaling proteins. Cycling with Hsp90 stabilizes client proteins, whereas Hsp70 interacts with chaperone-dependent E3 ubiquitin ligases to promote protein degradation. To probe these actions, small molecule inhibitors of Hsp70 would be extremely useful; however, few have been identified. Here we test the effects of methylene blue, a recently described inhibitor of Hsp70 ATPase activity, in three well established systems of increasing complexity. First, we demonstrate that methylene blue inhibits the ability of the purified Hsp90/Hsp70-based chaperone machinery to enable ligand binding by the glucocorticoid receptor and show that this effect is due to specific inhibition of Hsp70. Next, we establish that ubiquitination of neuronal nitric-oxide synthase by the native ubiquitinating system of reticulocyte lysate is dependent upon both Hsp70 and the E3 ubiquitin ligase CHIP and is blocked by methylene blue. Finally, we demonstrate that methylene blue impairs degradation of the polyglutamine expanded androgen receptor, an Hsp90 client mutated in spinal and bulbar muscular atrophy. In contrast, degradation of an amino-terminal fragment of the receptor, which lacks the ligand binding domain and, therefore, is not a client of the Hsp90/Hsp70-based chaperone machinery, is enhanced through homeostatic induction of autophagy that occurs when Hsp70-dependent proteasomal degradation is inhibited by methylene blue. Our data demonstrate the utility of methylene blue in defining Hsp70-dependent functions and reveal divergent effects on polyglutamine protein degradation depending on whether the substrate is an Hsp90 client.

  4. Titamium oxide (TiO2) assisted photocatalytic degradation of methylene blue.

    PubMed

    Madhu, G M; Raj, M A Lourdu Antony; Pai, K Vasantha Kumar

    2009-03-01

    The aqueous solution of methylene blue (MB) has been subjected to Photocatalytic degradation by UV radiation in presence of TiO2 photo-catalyst containing different concentrations of H2O2. The experiments conducted at different dye concentrations (12 and 20 ppm), catalyst loading, pH and H2O2 dosage (1-10 ml l(-1)), revealed that the degradation rate is strongly influenced by respective experimental parameters. However the influence of catalyst alone is not predominant in degradation. The decolorization of dye proceed to near completeness when H2O2 is used. The best degradation results are observed at 0.1 wt% of catalyst loading at pH 2 for TiO2/UV system. It has been found that the optimum concentration of H2O2 for 12 ppm and 20 ppm amount of the dye was 2 ml l(-1) for UV/H2O2 system. The kinetic of degradation of the dye followed the pseudo first order rate. The degradation studies using TiO2/UV/H2O2 system, indicates enhancement in the degradation rate of the dye compared to that of UV/H2O2 system alone.

  5. Comparative study for the removal of methylene blue via adsorption and photocatalytic degradation.

    PubMed

    El-Sharkawy, E A; Soliman, Afaf Y; Al-Amer, Kawthr M

    2007-06-15

    Physically and chemically activated carbons were prepared from date pits and olive stones. Titania and WO(x)-TiO(2)/MCM-41 were prepared as photoactive catalysts. Surface characterizations were investigated from ash content, pH, base neutralization capacities and FT-IR techniques. The textural characteristics, namely specific surface area (S(BET)) and pore texture, were determined from low temperature adsorption of N(2) at 77 K. The decolorization of aqueous solution of methylene blue was performed by means of two alternative methods. Steam-activated carbons own higher surface area compared with ZnCl(2)-activated carbons, and the micropore surface area represents the major contribution of the total area. Steam-activated carbons were the most efficient decolorizing adsorbents owing to its higher surface area, total pore volume and the basic nature of the surface. The calculated values of DeltaG(0), DeltaH(0) and DeltaS(0) indicate the spontaneous behavior of adsorption. The photocatalytic degradation is more convenient method in decolorizing of methylene blue compared with the adsorption process onto activated carbons.

  6. Adsorption and Photocatalytic Degradation of Methylene Blue Using Potassium Polytitanate and Solar Simulator.

    PubMed

    Shahid, Mohammad; El Saliby, Ibrahim; McDonagh, Andrew; Chekli, Laura; Tijing, Leonard D; Kim, Jong-Ho; Shon, Ho Kyong

    2016-05-01

    Solar photocatalytic degradation of organic water pollutants can be used to degrade toxic organic pollutants in water. In this study, potassium titanate nanofibres were synthesized by an aqueous peroxide route at high pH and examined as photocatalysts for photodegradation of methylene blue (MB) using a solar simulator. Initially, MB was adsorbed on the surface of potassium polytitanates to achieve adsorption equilibrium before the photocatalysts were illuminated using solar simulator. The results showed that potassium polytitanate nanofibres were effective adsorbents of MB and also facilitated its photocatalytic degradation. Sulphate ion evolution during photocatalysis confirmed that some mineralisation occurred and hence photo-oxidative degradation of MB took place. The optimum operational conditions for the photocatalytic degradation of MB were found at 0.05 g/L of photocatalyst load, 10 mg/L MB and pH 7. The stability and regeneration of the photocatalyst specimen was also studied for 3 degradation cycles using adsorption/photocatalysis model. Morphological structure analysis of potassium titanate showed nanocrystallines structure of longitudinally-oriented isolated fibre with a length up to several micrometres with diameters ranging from 10 to 20 nanometres.

  7. Mechanisms of Methylene Blue Degradation in Three-dimensionally Integrated Micro-solution Plasma

    NASA Astrophysics Data System (ADS)

    Nomura, Ayano; Hayashi, Yui; Tanaka, Kenji; Shirafuji, Tatsuru; Goto, Motonobu

    2015-09-01

    Plasma in aqueous solution has attracted much attention because they are expected to have possibilities to solve water-related environmental issues. In such application-oriented researches, degradation of methylene blue (MB) or other organic dyes has been widely used for investigating the effects of the plasma treatment on the water with organic contaminants. However, there are few reports on the detailed analysis of the products after the plasma treatment of MB aqueous solution for understanding mechanisms of the degradation processes. We have hence analyzed our degradation products using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. We have performed the MB degradation in three-dimensionally integrated micro-solution plasma, which has shown 16-fold higher performance in MB degradation than conventional solution plasma. The results of MALDI-TOF mass spectrometry have indicated the formation of sulfoxides in the first stage of the degradation. Then, the methyl groups on the sulfoxides are partially oxidized. The sulfoxides are separated to form two benzene derivatives after that. Finally, weak functional groups are removed from the benzene derivatives.

  8. Graphene-SnO2 composites for highly efficient photocatalytic degradation of methylene blue under sunlight.

    PubMed

    Seema, Humaira; Christian Kemp, K; Chandra, Vimlesh; Kim, Kwang S

    2012-09-07

    Graphene sheets decorated with SnO(2) nanoparticles (RGO-SnO(2)) were prepared via a redox reaction between graphene oxide (GO) and SnCl(2). Graphene oxide (GO) was reduced to graphene (RGO) and Sn(2+) was oxidized to SnO(2) during the redox reaction, leading to a homogeneous distribution of SnO(2) nanoparticles on RGO sheets. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show uniform distribution of the nanoparticles on the RGO surface and high-resolution transmission electron microscopy (HRTEM) shows an average particle size of 3-5 nm. The RGO-SnO(2) composite showed an enhanced photocatalytic degradation activity for the organic dye methylene blue under sunlight compared to bare SnO(2) nanoparticles. This result leads us to believe that the RGO-SnO(2) composite could be used in catalytic photodegradation of other organic dyes.

  9. New insights on degradation of methylene blue using thermocatalytic reactions catalyzed by low-temperature excitation.

    PubMed

    Luo, Xuegang; Zhang, Sizhao; Lin, Xiaoyan

    2013-09-15

    Although photocatalysis has been actively surveyed on removing organic pollutants in ultraviolet (UV) environment, because of lacking UV in solar exposure, photodegradation is difficult to be considerably degraded in conventional exposure condition. In this work, an innovative approach was proposed to compensate for it, which was developed in model wastewater using thermal sensitizer at room temperature. At the optimal component condition, the removal rate of adsorption and thermocatalytic degradation processes can reach the highest level of 82.07% solely response to temperature in the dark. Moreover, the kinetics of degradation rate was modeled considering that it was found similarly to Langmuir-Hinshelwood behavior, and a tentative mechanism was objectively established, describing reasonably well in line with the experimental results. On the other hand, it was found that high amount of methylene blue (MB) adsorbed onto thermal sensitizer was of unambiguous importance to subsequent thermocatalytic performance. Briefly, all above suggest that the feasibility to the thermodegradation route has been successfully verified under room temperature excitation. Herein the insight into degradation pattern of dye over thermal excitation may further enlarge applications for wastewater treatment.

  10. Photocatalytic Activity of W-Doped TiO2 Nanofibers for Methylene Blue Dye Degradation.

    PubMed

    Song, Yo-Seung; Cho, Nam-Ihn; Lee, Myung-Hyun; Kim, Bae-Yeon; Lee, Deuk Yong

    2016-02-01

    Photocatalytic degradation of methylene blue (MB) in water was examined using W-doped TiO2 nanofibers prepared by a sol-gel derived electrospinning and subsequent calcination for 4 h at 550 degrees C. Different concentrations of W dopant in the range of 0 to 8 mol% were synthesized to evaluate the effect of W concentration on the photocatalytic activity of TiO2. XRD results indicated that the undoped TiO2 is composed of anatase and rutile phases. The rutile phase was transformed to anatase phase completely with the W doping. Among W-TiO2 catalysts, the 2 mol% W-TiO2 catalyst showed the highest MB degradation rate. The degradation kinetic constant increased from 1.04 x 10(-3) min(-1) to 3.54 x 10(-3) min(-1) with the increase of W doping from 0 to 2 mol%, but decreased down to 1.77 x 10(-3) min(-1) when the W content was 8 mol%. It can be concluded that the degradation of MB under UV radiation was more efficient with W-TiO2 catalysts than with pure TiO2-

  11. Degradation of aqueous methylene blue using an external loop airlift sonophotoreactor: Statistical analysis and optimization.

    PubMed

    Mohajerani, Masroor; Mehrvar, Mehrab; Ein-Mozaffari, Farhad

    2016-07-28

    Degradation and mineralization of aqueous methylene blue (MB) are investigated in a bench scale external loop airlift sonophotoreactor. A central composite design along with response surface methodology is employed to model and optimize the sonophotolytic process. A quadratic empirical expression between responses and independent variables (pH and initial concentrations of H2O2 and MB) is derived. The efficiencies of the system for the MB degradation after 10, 15, and 30 min, and total organic carbon reduction after 150 min are considered as responses. The analysis of variance performed high values for the coefficient of determination R(2) and adjusted R(2) for all four responses. Optimum values of process variables for the maximum degradation and mineralization efficiency are pH 6.6 and initial concentrations of H2O2 and MB are 1,280 and 10.56 mg/L, respectively. With optimal operating conditions, 99.93% and 55.32% MB removal (after 10 min) and TOC reduction (after 150 min) are achieved, respectively. Artificial neural networks are also used to model the experimental data. The respirometric study is conducted to compare the biodegradability of untreated and sonophotolytically pre-treated MB solutions at different reaction times. Pre-treated solutions at 180, 240, and 300 min performed higher biodegradability compared to those of untreated MB solutions.

  12. Ag-ligand modified tungstovandates and their efficient catalysis degradation properties for methylene blue

    NASA Astrophysics Data System (ADS)

    Zheng, Ran; Zhang, Huixia; Liu, Yunping; Wang, Xiaoxiao; Han, Zhangang

    2017-02-01

    Two polytungstovandates [Ag(mbpy)2][Ag2(mbpy)3][VW5O19]·H2O (1) and [Ag(mbpy)]2[Ag(mbpy)2]4[VW12O40] (2) (mbpy =4,4‧-dimethyl-2,2‧-bipyridyl), had been hydrothermally synthesized and characterized by IR, TG, and single-crystal X-ray diffraction techniques. Single-crystal structural analysis revealed that the polyanionic clusters in two compounds are different: Lindqvist-type in 1 and α-Keggin-type in 2, respectively, while the cationic moieties in them are Ag-mbpy units. The experiments showed that this kind of hybrid crystal materials possesses more efficiently catalytic performance for the degradation of organic dye methylene blue (MB) in water solution under the UV irradiation. The significant degradation rate of MB can reach 89.9%, 94.9% by crystals 1 and 2 (40 mg) in the course of about 5 min.

  13. Effective ultrasound electrochemical degradation of methylene blue wastewater using a nanocoated electrode.

    PubMed

    Yang, Bo; Zuo, Jiane; Tang, Xinhua; Liu, Fenglin; Yu, Xin; Tang, Xinyao; Jiang, Hui; Gan, Lili

    2014-07-01

    A novel sonoelectrochemical catalytic oxidation-driven process using a nanocoated electrode to treat methylene blue (MB) wastewater was developed. The nano-scale (nanocoated) electrode generated more hydroxyl radicals than non-nano-scale (non-nanocoated) electrodes did. However, hydroxyl radicals were easily adsorbed by the nanomaterial and thus were not able to enter the solution. Supersonic waves were found to enhance the mass-transfer effect on the nanocoated electrode surface, resulting in rapid diffusion of the generated hydroxyl radicals into the solution. In solution, the hydroxyl radicals then reacted with organic pollutants in the presence of ultrasonic waves. The effect of the nanocoated electrode on the MB wastewater treatment process was enhanced by ultrasound when compared to the non-nanocoated electrode used under the same conditions. The synergy of the nanocoated electrode and ultrasonic waves towards MB degradation was then studied. The optimum operating conditions resulted in a 92% removal efficiency for TOC and consisted of a current of 600 mA, an ultrasound frequency of 45 kHz, and a supersonic power of 250 W. The mechanism of ultrasound enhancement of the nanocoated electrode activity with respect to MB treatment is discussed. The reaction intermediates of the sonoelectrochemical catalytic oxidation process were monitored, and degradation pathways were proposed. The sonoelectrochemical catalytic oxidation-driven process using nanocoated electrodes was found to be a very efficient method for the treatment of non-biodegradable wastewater.

  14. Kinetics of Photocatalytic Degradation of Methylene Blue by TiO₂-Graphene Nanocomposites.

    PubMed

    Loryuenyong, Vorrada; Charoensuk, Jaruwan; Charupongtawitch, Rachaya; Usakulwattana, Amika; Buasri, Achanai

    2016-01-01

    Reduced graphene oxide (RGO)/TiO₂ nanocomposite was successfully prepared by UV-assisted photocatalytic reduction of graphene oxide (XGO) by TiO₂ nanoparticles in ethanol. The effects of XGO and RGO addition in TiO₂were characterized by transmission electron microscopy (TEM), X-ray diffractometer (XRD), diffuse reflectance UV-vis spectrophotometer (UV-vis), fourier-transform infrared spectroscopy (FTIR), photoluminescence (PL), and Brunauer-Emmett-Teller (BET) and Barrett-Joiner-Halenda (BJH) porosity analysis. The photocatalytic activity of prepared nanocomposites was evaluated from the kinetics of the photocatalytic degradation of cationic methylene blue dye under UV irradiation. Bandgap, the electron-hole recombination, specific surface area, surface functional groups, and adsorption capacity of nanocomposites were found to play a significant role in the degradation. The results revealed that RGO/TiO₂ and XGO/TiO₂ nanocomposites exhibited efficient charge separation and enhanced photocatalytic activity, compared to pristine TiO₂. Nearly 500% improvement was observed in this work.

  15. Low-temperature synthesis and investigations on photocatalytic activity of nanoparticles BiFeO3 for methylene blue and methylene orange degradation and some toxic organic compounds

    NASA Astrophysics Data System (ADS)

    Nhiem Dao, Ngoc; Luu, Minh Dai; Chuc Pham, Ngoc; Dung Doan, Trung; Nguyen, Thi Ha Chi; Bac Nguyen, Quang; Lim Duong, Thi

    2016-12-01

    The photocatalytic BiFeO3 perovskite nanoparticles were fabricated by gel combustion method using polyvinyl alcohol and corresponding metal nitrate precursors under the optimum mild conditions such as pH 2, gel formation temperature of 80 °C, metal/polyvinyl alcohol molar ratio of 1/3, metal molar ratio Bi/Fe of 1/1 and calcination temperature at 500 °C for 2 h. The prepared sample was characterized by x-ray diffraction, field scanning electron microscopy, transmission electron microscopy, Brunauer-Emmetl-Teller nitrogen adsorption method at 77 K, energy dispersive x-ray spectroscopy, ultraviolet-visible light spectrophotometry, and thermal analysis. The effects of molar ratios of starting material and calcination temperature on phase formation and morphology were investigated. The degradation of methylene blue, methylene orange and some toxic organic compounds such as phenol and diazinon under visible light irradiation by photocatalytic BiFeO3 nanoparticles were evaluated at different parameters and conditions such as the light intensity determined from the light source to the measured sample, the addition H2O2, reaction time and the regeneration performance. Obtained results showed that the synthesized perovskite BiFeO3 nanoparticles for the optimized sample have a size smaller than 50 nm and the high mean surface area of 50 m2 g-1. Degradation efficiency was almost 90.0% for methylene blue and 80.0% for methylene orange with added H2O2 after 30 min of reaction. After the 3rd time of regeneration, the BiFeO3 nanoparticles still have 92.8% of the degradation performance for removing methylene blue. Phenol and diazinon toxic compound were degraded with the performance of 92.42% and 85.7%, respectively, for 150 min

  16. Photo-degradation of methylene blue using Ta-doped ZnO nanoparticle

    SciTech Connect

    Kong Jizhou; Li Aidong; Li Xiangyu; Zhai Haifa; Zhang Wenqi; Gong Youpin; Li Hui; Wu Di

    2010-06-15

    A photocatalyst of Ta-doped ZnO was prepared by a modified Pechini-type method. The structural, morphological properties and photocatalytic activity of 1 mol % Ta-doped ZnO samples annealed at different temperatures were characterized. The photo-oxidation of methylene blue under the visible-light irradiation followed the pseudo-first-order kinetics according to the Langmuir-Hinshelwood model. It is found that the photocatalysis of 1% Ta-doped ZnO annealed at 700 {sup o}C showed excellent performance of the photodegradation of methylene blue, which was attributed to a competitive trade-off among the crystallinity, surface hydroxyl groups, and specific surface area. The processing parameter such as the pH value also played an important role in tuning the photocatalytic activity. The maximum photodecomposed rate was achieved at pH=8, and an novel model about the absorption of methylene blue on the surface of the catalysts was proposed. - Graphical abstract: This model describes the adsorption between the amphoteric behavior of the metal oxide and the cationic dye methylene blue (MB) on the surface of the catalyst at the acidic and alkaline condition.

  17. ZnO microspheres-reduced graphene oxide nanocomposite for photocatalytic degradation of methylene blue dye

    NASA Astrophysics Data System (ADS)

    Qin, Jiaqian; Zhang, Xinyu; Yang, Chengwu; Cao, Meng; Ma, Mingzhen; Liu, Riping

    2017-01-01

    In this work, ZnO microspheres-reduced graphene oxide (rGO) nanocomposites were synthesized via a simple solution method and used for the photodegradation of methylene blue (MB) dye from water under UV light. The SEM and TEM observations demonstrate that the microsphere morphologies of the ZnO microspheres-rGO nanocomposite is composed of ZnO microspheres anchored on rGO sheets, confirming the formation of ZnO microspheres-rGO composites. Raman spectra and X-ray photoelectron spectroscopy reveal that both of the reduction of GO tight contact between ZnO and rGO are achieved during the high temperature calcination process. During the photocatalytic test, in comparison with ZnO microspheres and P25 TiO2, the ZnO microspheres-rGO nanocomposite shows improved photodegradation of MB dye, because the rGO sheets could reduce the charge recombination in electron-transfer processes. According to the scavenger experiments, the possible MB degradation mechanism is contributed mainly to the generation of active species induced by the photogenerated holes (h+) and superoxide radicals (rad O2-).

  18. Catalytic degradation of methylene blue by biosynthesised copper nanoflowers using F. benghalensis leaf extract.

    PubMed

    Agarwal, Meenakshi; Singh Bhadwal, Akhshay; Kumar, Nishant; Shrivastav, Archana; Raj Shrivastav, Braj; Pratap Singh, Manoj; Zafar, Fahmina; Mani Tripathi, Ravi

    2016-10-01

    This study reports the unprecedented, novel and eco-friendly method for the synthesis of three-dimensional (3D) copper nanostructure having flower like morphology using leaf extract of Ficus benghalensis. The catalytic activity of copper nanoflowers (CuNFs) was investigated against methylene blue (MB) used as a modal dye pollutant. Scanning electron micrograph evidently designated 3D appearance of nanoflowers within a size range from 250 nm to 2.5 μm. Energy-dispersive X-ray spectra showed the presence of copper elements in the nanoflowers. Fourier-transform infrared spectra clearly demonstrated the presence of biomolecules which is responsible for the synthesis of CuNFs. The catalytic activity of the synthesised CuNFs was monitored by ultraviolet-visible spectroscopy. The MB was degraded by 72% in 85 min on addition of CuNFs and the rate constant (k) was found to be 0.77 × 10(-3) s(-1). This method adapted for synthesis of CuNFs offers a valuable contribution in the area of nanomaterial synthesis and in water research by suggesting a sustainable and an alternative route for removal of toxic solvents and waste materials.

  19. Pyrite-enhanced methylene blue degradation in non-thermal plasma water treatment reactor.

    PubMed

    Benetoli, Luís Otávio de Brito; Cadorin, Bruno Mena; Baldissarelli, Vanessa Zanon; Geremias, Reginaldo; de Souza, Ivan Gonçalvez; Debacher, Nito Angelo

    2012-10-30

    In this study, methylene blue (MB) removal from an aqueous phase by electrical discharge non-thermal plasma (NTP) over water was investigated using three different feed gases: N(2), Ar, and O(2). The results showed that the dye removal rate was not strongly dependent on the feed gas when the electrical current was kept the same for all gases. The hydrogen peroxide generation in the water varied according to the feed gas (N(2)degradation occurs via high energy electron impact as well as successive hydroxylation in the benzene rings of the dye molecules.

  20. AgBr/nanoAlMCM-41 visible light photocatalyst for degradation of methylene blue dye.

    PubMed

    Pourahmad, A; Sohrabnezhad, Sh; Kashefian, E

    2010-12-01

    A novel photocatalytic material was synthesized by dispersion of AgBr in nanoAlMCM-41 material. The AgBr/nanoAlMCM-41 sample shows strong absorption in the visible region because of the plasmon resonance of Ag nanoparticles in AgBr/nanoAlMCM-41. The catalysts were characterized using XRD (X-ray diffraction), UV-visible diffused reflectance spectra (UV-vis DRS) and scanning electron microscopy (SEM). The photocatalytic activity and stability of the synthesized catalysts were evaluated for methylene blue (MB) degradation in aqueous solution in the presence of 200 W tungsten filament Philips lamp. Several parameters were examined, catalyst amount, pH and initial concentration of MB, AgBr loading. The effect of dosage of photocatalyst was studied in the range 0.05-1.00 g/L. It was seen that 0.1 g/L of photocatalyst is an optimum value for the dosage of photocatalyst. The support size was obtained about 9-100 nm. In the same way, the average size of AgBr nanoparticles was about 10nm before visible radiation. After visible radiation the average size of AgBr nanoparticles was about 25 nm.

  1. Photocatalytic degradation of methylene blue under UV light irradiation on prepared carbonaceous TiO2.

    PubMed

    Ramli, Zatil Amali Che; Asim, Nilofar; Isahak, Wan N R W; Emdadi, Zeynab; Ahmad-Ludin, Norasikin; Yarmo, M Ambar; Sopian, K

    2014-01-01

    This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC), TiO2/carbon (C), and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC) was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TG-DTA), Brunauer-Emmet-Teller (BET), and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2 (179 > 134 > 54 > 9 m(2) g(-1)). The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.

  2. Photocatalytic activity of SnO{sub 2} nanoparticles in methylene blue degradation

    SciTech Connect

    Kim, Sung Phil; Choi, Myong Yong; Choi, Hyun Chul

    2016-02-15

    Highlights: • Nanosized SnO{sub 2} photocatalysts were prepared with a precipitation method. • SnO{sub 2} nanoparticles displayed high photocatalytic activities for the MB degradation. • OH radicals are the main active species in photocatalysis on the SnO{sub 2} nanoparticles. - Abstract: Nanosized SnO{sub 2} photocatalysts were prepared with a precipitation method and were characterized by performing transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). The powder XRD results revealed that the SnO{sub 2} nanoparticles have a typical tetragonal rutile (cassiterite) structure and the average crystallite size was found to be approximately 4.5 nm by using the Debye–Scherrer equation. The prepared SnO{sub 2} nanoparticles consist of agglomerated particles with a mean diameter of around 4–5 nm according to the analysis of TEM images. The XAS data confirmed that the prepared samples have cassiterite structures with tin oxidation state of +4. The prepared SnO{sub 2} nanoparticles were found to exhibit approximately 3.8 times higher activity than bulk SnO{sub 2} in the photodegradation of methylene blue. On the basis of a trapping experiment, we developed a possible mechanism for the photodegradation on SnO{sub 2} nanoparticles.

  3. Use of pectin-thorium (IV) tungstomolybdate nanocomposite for photocatalytic degradation of methylene blue.

    PubMed

    Gupta, Vinod Kumar; Agarwal, Shilpi; Pathania, Deepak; Kothiyal, N C; Sharma, Gaurav

    2013-07-01

    Pectin-thorium (IV) tungstomolybdate (Pc/TWM) nanocomposite was prepared by mixing biopolymer pectin with its inorganic counterpart thorium (IV) tungstomolybdate (TWM) using the sol-gel method. The nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Distribution coefficient, thermal stability, pH titrations, elution and concentration behaviour were investigated to explore the ion exchange behaviour of nanocomposite material. Pc/TWM exhibited higher ion exchange capacity (1.10 mequiv/g) than its inorganic counterpart (0.62 mequiv/g). The Pc/TWM nanocomposite ion exchanger was thermally stable as it retained 59% of its ion exchange capacity upto 400°C. The pH titrations study revealed the bifunctional nature of Pc/TWM. In order to explore the environmental applicability of the Pc/TWM nanocomposite material, its antibacterial and photocatalytic activities was investigated. 76% of methylene blue dye was photocatalytically degraded after five hours exposure. It also totally inhibited Escherichia coli at 400 μg/ml concentration of Pc/TWM nanocomposite.

  4. Photocatalytic degradation of methylene blue with Fe doped ZnS nanoparticles.

    PubMed

    Chauhan, Ruby; Kumar, Ashavani; Chaudhary, Ram Pal

    2013-09-01

    Fe doped ZnS nanoparticles (Zn1-xFexS; where x=0.00, 0.03, 0.05 and 0.10) were synthesized by a chemical precipitation method. The synthesized products were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, UV-Vis and photoluminescence spectrometer. The X-ray diffraction and transmission electron microscope studies show that the size of crystallites is in the range of 2-5 nm. Photocatalytic activities of ZnS and 3, 5 and 10 mol% Fe doped ZnS were evaluated by decolorization of methylene blue in aqueous solution under ultraviolet and visible light irradiation. It was found that the Fe doped ZnS bleaches methylene blue much faster than the undoped ZnS upon its exposure to the visible light as compared to ultraviolet light. The optimal Fe/Zn ratio was observed to be 3 mol% for photocatalytic applications.

  5. Photocatalytic degradation of methylene blue with Fe doped ZnS nanoparticles

    NASA Astrophysics Data System (ADS)

    Chauhan, Ruby; Kumar, Ashavani; Chaudhary, Ram Pal

    2013-09-01

    Fe doped ZnS nanoparticles (Zn1-xFexS; where x = 0.00, 0.03, 0.05 and 0.10) were synthesized by a chemical precipitation method. The synthesized products were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, UV-Vis and photoluminescence spectrometer. The X-ray diffraction and transmission electron microscope studies show that the size of crystallites is in the range of 2-5 nm. Photocatalytic activities of ZnS and 3, 5 and 10 mol% Fe doped ZnS were evaluated by decolorization of methylene blue in aqueous solution under ultraviolet and visible light irradiation. It was found that the Fe doped ZnS bleaches methylene blue much faster than the undoped ZnS upon its exposure to the visible light as compared to ultraviolet light. The optimal Fe/Zn ratio was observed to be 3 mol% for photocatalytic applications.

  6. Highly efficient photocatalytic degradation of methylene blue by PoPD/TiO2 nanocomposite

    PubMed Central

    Dong, Wenping; Cui, Guanwei; Ren, Zongming

    2017-01-01

    The poly-o-phenylenediamine (PoPD)/TiO2 nanocomposite was successfully synthesized via ‘in situ’ oxidative polymerization method. The modified photocatalysts were characterized by BET, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrarad spectra (FT-IR), thermogravimrtic analysis (TGA), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible diffuse reflectance spectrum (UV-Vis DRS) and Photocurrent Test. The results showed that the PoPD exists on the surface of TiO2, the presence of PoPD does not impact on the lattice structure and grain size of TiO2, and the presence of PoPD enhances the visible response and photoelectric property. The photocatalytic degradation of methylene blue (MB) was chosen as a model reaction to evaluate the photocatalytic activities of TiO2 and PoPD/TiO2. The optimal preparation condition was the molar ratio of oPD to TiO2 = 3:1, HCl concentration = 1.2 mol/L, the molar ratio of APS to oPD = 1:1. The apparent first-order rate constant kapp of PoPD/TiO2 nanocomposite was 0.0098 min-1, which is 6 times higher than TiO2 (0.0016 min-1). Meanwhile, the PoPD/TiO2 nanocomposites showed excellent photocatalytic stability, and the photocatalytic stability was depended on the stability of structure. At last, the photocatalytic mechanism of POPD/TiO2 nanocomposites was also proposed based on the synergetic effect between TiO2 and PoPD. PMID:28329007

  7. Synthesis and characterization of TiO2 pillared montmorillonites: application for methylene blue degradation.

    PubMed

    Chen, Daimei; Du, Gaoxiang; Zhu, Qian; Zhou, Fengsan

    2013-11-01

    TiO2 pillared clay composites were prepared by modifying of montmorillonite (Mt) with cetyl-trimethyammoniumbromide (CTAB) and then using an acidic solution of hydrolyzed Ti alkoxide to intercalate into the interlayer space of the organic modified Mt. The as-prepared materials were characterized by XRD, FTIR, TEM, SEM TG-DTA, specific surface area and porosity measurements. The composites had a porous delaminated structure with pillared fragments and well dispersed TiO2 nanoparticles. Introduction of CTAB into the synthetic system accelerated the hydrolysis and condensation of the Ti source, which promoted TiO2 formation. In addition, the CTAB also significantly increased the porosity and surface area of the composites. A number of anatase particles, with crystal sizes of 5-10 nm, were homogenously distributed on the surface of the Mt as the result of the templating role of CTAB. The resultant TiO2 pillared Mt exhibited good thermal stability as indicated by its surface area after calcination at 800°C. No phase transformations from anatase to rutile were observed even under calcination at 900°C. The grain size of the anatase in prepared sample increased from 2.67 nm to 13.42 nm as the calcination temperature increased from 300°C to 900°C. The photocatalytic performance of these new porous materials was evaluated by using methylene blue degradation. The composite exhibited better photocatalytic property than P 25. The maximum removal efficiency of this composite was up to 99% within 60 min.

  8. Highly efficient photocatalytic degradation of methylene blue by PoPD/TiO2 nanocomposite.

    PubMed

    Yang, Chuanxi; Zhang, Ming; Dong, Wenping; Cui, Guanwei; Ren, Zongming; Wang, Weiliang

    2017-01-01

    The poly-o-phenylenediamine (PoPD)/TiO2 nanocomposite was successfully synthesized via 'in situ' oxidative polymerization method. The modified photocatalysts were characterized by BET, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrarad spectra (FT-IR), thermogravimrtic analysis (TGA), X-ray photoelectron spectroscopy (XPS), Ultraviolet-visible diffuse reflectance spectrum (UV-Vis DRS) and Photocurrent Test. The results showed that the PoPD exists on the surface of TiO2, the presence of PoPD does not impact on the lattice structure and grain size of TiO2, and the presence of PoPD enhances the visible response and photoelectric property. The photocatalytic degradation of methylene blue (MB) was chosen as a model reaction to evaluate the photocatalytic activities of TiO2 and PoPD/TiO2. The optimal preparation condition was the molar ratio of oPD to TiO2 = 3:1, HCl concentration = 1.2 mol/L, the molar ratio of APS to oPD = 1:1. The apparent first-order rate constant kapp of PoPD/TiO2 nanocomposite was 0.0098 min-1, which is 6 times higher than TiO2 (0.0016 min-1). Meanwhile, the PoPD/TiO2 nanocomposites showed excellent photocatalytic stability, and the photocatalytic stability was depended on the stability of structure. At last, the photocatalytic mechanism of POPD/TiO2 nanocomposites was also proposed based on the synergetic effect between TiO2 and PoPD.

  9. Photocatalytic degradation of methylene blue over nanosized TiO2 particles prepared using the self-propagating high-temperature synthesis method.

    PubMed

    Park, Chul-Min; Seo, Hyeong-Seok; Cho, Jung-Ho; Choi, Da-Hye; Jeong, Young-Shin; Chung, Min-Chul; Jung, Sang-Chul; Jeong, Woon-Jo; Ban, Jae-Sam; Ahn, Ho-Geun

    2013-08-01

    In order to reutilize the spent metallic titanium chips, TiO2 photocatalysts were prepared using the self-propagating high-temperature synthesis (SHS) method, and were characterized by N2 gas adsorption, X-ray diffraction, and scanning electron microscope, particle size distribution. Also, their photocatalytic activities were evaluated using methylene blue as a model organic compound. It was confirmed that the crystal structure of TiO2 prepared by SHS method was relatively homogeneous powder of rutile type. Optimum conditions for photocatalytic degradation of methylene blue under UV-C irradiation were methylene blue 9.5 ppm in solution and at amount of TiO2 added of 0.02 g/L. In addition, it was found that the photocatalytic activity for methylene blue degradation over the prepared TiO2 particles was positively related with BET specific surface area.

  10. Design and synthesis of metal complexes of (2E)-2-[(2E)-3-phenylprop-2-en-1-ylidene]hydrazinecarbothioamide and their photocatalytic degradation of methylene blue.

    PubMed

    Krishna, P Murali; Reddy, N B Gopal; Kottam, Nagaraju; Yallur, B C; Katreddi, Hussain Reddy

    2013-01-01

    The photocatalytic degradation has been considered to be an efficient process for the degradation of organic pollutants, which are present in the effluents released by industries. The photocatalytic bleaching of cationic dye methylene blue was carried out spectrometrically on irradiation of UV light using Cu(II), Ni(II), and Co(II) complexes of (2E)-2-[(2E)-3-phenylprop-2-en-1-ylidene]hydrazinecarbothioamide (HL). The effects of pH and metal ion were studied on the efficiency of the reaction. Cu(II) complex shows better catalytic activity and the highest percentage degradation (~88.8%) of methylene blue was observed at pH 12. A tentative mechanism has also been proposed for the photocatalytic degradation of methylene blue.

  11. Influence of activated carbon upon the photocatalytic degradation of methylene blue under UV-vis irradiation.

    PubMed

    Matos, Juan; Montaña, Ricmary; Rivero, Eliram

    2015-01-01

    Photodegradation of methylene blue (MB) was studied on TiO2 in the presence of activated carbon (AC) prepared from the sawdust of a soft wood by physical activation under CO2 flow, by pyrolysis under N2 flow, and by chemical activation with ZnCl2 and H3PO4 under N2 flow. MB photodegradation was performed under UV and UV-visible irradiation to verify the scaling-up of the present TiO2-AC binary materials. It was verified that oxygenated surface groups on carbon were intrinsically photoactive, and a synergy effect between both solids has been estimated from the first-order apparent rate constants in the photodegradation of MB. This effect enhances the photoactivity of TiO2 up to a factor of about 9 under visible irradiation, and it was associated to the surface properties of AC.

  12. Catalytic degradation of methylene blue using biosynthesized gold and silver nanoparticles.

    PubMed

    Suvith, V S; Philip, Daizy

    2014-01-24

    The scientific community is searching for new synthesis methods for the production of metallic nanoparticles. Green synthesis has now become a vast developing area of research. Here we report for the first time to best of our knowledge, a new green method for the synthesis of silver and gold nanoparticles using the Kashayam, Guggulutiktham, an ayurvedic medicine. This method is nontoxic and environmentally benign. The reduction and the stabilization capacity of the ayurvedic Kashayam are described in this paper. The size and shape of the silver and gold nanoparticles can be tuned by varying the quantity of the Kashayam. The synthesized nanoparticles are characterized using UV-VIS spectroscopy, TEM, XRD and FTIR. The size dependent catalytic activity of the synthesized nanoparticles is established in the reduction of Methylene Blue (MB) by NaBH4.

  13. Preparation and characterization of Cu{sub 2}O-TiO{sub 2}: Efficient photocatalytic degradation of methylene blue

    SciTech Connect

    Xu Yuehua Liang Dahui; Liu Manle; Liu Dingzhong

    2008-12-01

    A series of copper-deposited titania were prepared by photoreduction method under irradiation with a 125-W high-pressure mercury lamp. From XPS and AES results, the deposited-copper formed Ti-O-Cu bond on the surface of TiO{sub 2}, and the Cu species on the surface of copper-deposited TiO{sub 2} can be identified as Cu(I). The photocatalytic degradation activity of methylene blue for the Cu{sub 2}O-TiO{sub 2} series increased with increasing Cu{sub 2}O-deposited content, and then decreased. The highest photocatalytic degradation activity of methylene blue was obtained for 0.16% Cu{sub 2}O-TiO{sub 2}. When copper-deposited content reached to 0.32%, the photocatalytic activity was lower than that of pure TiO{sub 2}. It is shown that Cu{sub 2}O on the surface of TiO{sub 2} can trap electrons from the TiO{sub 2} conduction band, and the electrons trapped on the Cu{sub 2}O-TiO{sub 2} site are subsequently transferred to the surrounding adsorbed O{sub 2}, thereby avoiding electron-hole recombination, and enhancing the photocatalytic activity. Excess copper loading may screen the photocatalyst from the UV source, so the photocatalytic activity diminishes with increasing Cu{sub 2}O.

  14. Methylene blue degradation by NaTaO3 sol-gel doped with Sm and La.

    PubMed

    Torres-Martínez, Leticia M; Cruz-López, Arquímedes; Juárez-Ramírez, Isaías; Meza-de la Rosa, Ma Elena

    2009-06-15

    In this work, NaTaO(3) compounds doped with 1M% of La and Sm, were prepared by the sol-gel (SG) method and solid state (SS) reaction; and tested as photocatalysts on the degradation of methylene blue (MB) under UV light. The structural characterization by X-ray powder diffraction revealed that the crystallization of the NaTaO(3) phase prepared by the sol-gel method started at 600 degrees C, reaching maximum crystallization at 800 degrees C. It was determined that the presence of Sm and La retard the crystallization of the NaTaO(3) phase. On the other hand, the compounds synthesized in this work showed particle sizes in the nanometric scale, as it was observed by scanning electron microscopy (SEM). The specific surface area of the compounds synthesized by the sol-gel method, showed values 4 times higher than those obtained by the solid state reaction, favoring their functional and photocatalytic performance in the methylene blue degradation. In addition, the best photocatalytic performance was shown by the NaTaO(3) doped with Sm and heated at 600 degrees C, having a half-life time of 65 min.

  15. Precursor effects on the morphology and crystallinity of manganese oxides and their catalytic application for methylene blue degradation

    NASA Astrophysics Data System (ADS)

    Awaluddin, Amir; Agustina, Mutia; Aulia, Rizki Rilda; Muhdarina

    2017-03-01

    The cryptomelane-type manganese oxide catalysts have been prepared by sol-gel method based on the redox reaction between potassium permanganate and glucose or oxalic acid. These catalysts belong to a class of porous manganese oxides known as octahedral molecular sieves (OMS). The SEM results indicated that the marked difference between the morphology of the cyptomelanes produced from glucose and oxalic acid. The glucose precursor produces cotton-shaped morphology, whereas the oxalic acid precursor leads to the formation of the disk-like appearances. The XRD results indicated that the glucose precursor produces more crystalline cryptomelane than that of oxalic acid. The effect of catalyst dosage on methyelene blue degradation was evaluated. Dye-decomposing activity was proportional to the amount of catalyst used, increasing of the catalyst amount leads to higher degradation of methyelene blue at short period of reaction. With different crystalline structures and morphology appearances of the cyptomelanes, however, the total degradation of methylene blue is relatively the same at 120 minute of reaction time with catalyst amount of 100 mg.

  16. 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.

  17. Synthesis, Characterization and Application of Cobalt Incorporated Mesoporous KIT-6 for the Visible Light Assisted Degradation of Methylene Blue.

    PubMed

    Sanjini, N S; Winston, B; Velmathi, S

    2015-09-01

    Highly ordered mesoporous three dimensional la3d cobalt doped KIT-6 (Co-KIT-6) material was synthesized by the simple impregnation method and characterized by various physicochemical techniques such as X-ray diffraction, N2 adsorption-desorption isotherm, diffuse reflectance spectroscopy, Fourier transform infra-red spectroscopy and scanning electron microscopy. Larger pore diameter tuned with a narrow size distribution was observed for prepared Co-KIT-6. A series of Co-KIT-6 with different weight percentages solutions were prepared and the photocatalytic efficacy of the samples for degradation of methylene blue was studied under UV and visible light using UV-visible spectrophotometer. It was found that the catalytic activity depends on the amount of cobalt incorporated into the material. The complete degradation of dye was observed within 50 min. Different amount of catalyst and reaction time was considered for the optimization studies.

  18. Photocatalytic degradation of methylene blue dye by zinc oxide nanoparticles obtained from precipitation and sol-gel methods.

    PubMed

    Balcha, Abebe; Yadav, Om Prakash; Dey, Tania

    2016-12-01

    Zinc oxide (ZnO) nanoparticles were synthesized by precipitation and sol-gel methods. The aim of this study was to understand how different synthetic methods can affect the photocatalytic activity of ZnO nanoparticles. As-synthesized ZnO nanoparticles were characterized by X-ray diffraction (XRD) and UV-Visible spectroscopic techniques. XRD patterns of ZnO powders synthesized by precipitation and sol-gel methods revealed their hexagonal wurtzite structure with crystallite sizes of 30 and 28 nm, respectively. Their photocatalytic activities were evaluated by photocatalytic degradation of methylene blue, a common water pollutant, under UV radiation. The effects of operational parameters such as photocatalyst load and initial concentration of the dye on photocatalytic degradation of methylene blue were investigated. While the degradation of dye decreased over the studied dye concentration range of 20 to 100 mg/L, an optimum photocatalyst load of 250 mg/L was needed to achieve dye degradation as high as 81 and 92.5 % for ZnO prepared by precipitation and sol-gel methods, respectively. Assuming pseudo first-order reaction kinetics, this corresponded to rate constants of 8.4 × 10(-3) and 12.4 × 10(-3) min(-1), respectively. Hence, sol-gel method is preferred over precipitation method in order to achieve higher photocatalytic activity of ZnO nanostructures. Photocatalytic activity is further augmented by better choice of capping ligand for colloidal stabilization, starch being more effective than polyethylene glycol (PEG).

  19. Plasmon-assisted degradation of methylene blue with Ag/AgCl/montmorillonite nanocomposite under visible light.

    PubMed

    Sohrabnezhad, Sh; Zanjanchi, M A; Razavi, M

    2014-09-15

    Metal-semiconductor compounds, such as Ag/AgX (X=Cl, Br, I), enable visible light absorption and separation of photogenerated electron-hole through surface plasmon resonance (SPR) effect. However, the electron-hole generated and separated by light are vulnerable in Ag/AgX phase because of the occurrence of secondary recombined. In order to more effectively utilize the SPR photocatalytic effect, nanoparticles are located in a matrix. In this article, Ag/AgCl nanoparticles were synthesized in montmorillonite (MMT) matrix using dispersion method and light irradiation. The structure, composition and optical properties of such material were investigated by transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray diffraction (XRD) and FTIR. Powder X-ray diffraction showed intercalation of Ag/AgCl nanoparticles into the clay layers. The as-prepared plasmonic photocatalyst exhibited an enhanced and stable photoactivity for the degradation of methylene blue (MB) under visible light. The high activity was attributed to the surface plasmon resonance (SPR) exhibited by Ag nanoparticles on the surface of AgCl. The detection of reactive species by radical scavengers displays that O2- and OH- are the main reactive species for the degradation of MB under visible light irradiation. The studies showed that 20 min illumination under visible light can complete degradation of methylene blue (MB), and indicate a high stability of photocatalytic degradation. The mechanism of separation of the photo-generated electrons and holes at the Ag/AgCl-MMT nanocomposite was discussed.

  20. Comparison of Catalytic Activities for Sonocatalytic, Photocatalytic and Sonophotocatalytic Degradation of Methylene Blue in the Presence of Magnetic Fe3O4/CuO/ZnO Nanocomposites

    NASA Astrophysics Data System (ADS)

    Taufik, Ardiansyah; Tju, Hendry; Saleh, Rosari

    2016-04-01

    Fe3O4/CuO/ZnO nanocomposites with different molar ratio were synthesized using sol-gel method. The as-synthesized samples were characterized by X-ray diffraction (XRD), UV-visible spectroscopy, BET surface area analyszer, and Electron Spin Resonance (ESR). The sonocatalytic-photocatalytic-sonophotocatalytic activity of as-synthesized samples was investigated based on methylene blue degradation. Moreover, the role of active species was investigated using scavenger technique. The results showed that hole plays an important key role in sono-photo-sonophotocatalytic degradation of methylene blue.

  1. Microwave synthesis of pure and doped cerium (IV) oxide (CeO2) nanoparticles for methylene blue degradation.

    PubMed

    El Rouby, W M A; Farghali, A A; Hamdedein, A

    2016-11-01

    Cerium (IV) oxide (CeO2), samarium (Sm) and gadolinium (Gd) doped CeO2 nanoparticles were prepared using microwave technique. The effect of microwave irradiation time, microwave power and pH of the starting solution on the structure and crystallite size were investigated. The prepared nanoparticles were characterized using X-ray diffraction, FT-Raman spectroscopy, and transmission electron microscope. The photocatalytic activity of the as-prepared CeO2, Sm and Gd doped CeO2 toward degradation of methylene blue (MB) dye was investigated under UV light irradiation. The effect of pH, the amount of catalyst and the dye concentration on the degradation extent were studied. The photocatalytic activity of CeO2 was kinetically enhanced by trivalent cation (Gd and Sm) doping. The results revealed that Gd doped CeO2 nanoparticles exhibit the best catalytic degradation activity on MB under UV irradiation. For clarifying the environmental safety of the by products produced from the degradation process, the pathways of MB degradation were followed using liquid chromatography/mass spectroscopy (LC/MS). The total organic carbon content measurements confirmed the results obtained by LC/MS. Compared to the same nanoparticles prepared by another method, it was found that Gd doped CeO2 prepared by hydrothermal process was able to mineralize MB dye completely under UV light irradiation.

  2. Enhanced photocatalytic activity of TiO₂-C hybrid aerogels for methylene blue degradation.

    PubMed

    Shao, Xia; Lu, Wencong; Zhang, Rui; Pan, Feng

    2013-10-22

    Carbon-based TiO₂ composites have many advantages as photocatalysts. However, they suffer from low light efficiency due to the low contrast of TiO₂ with carbon. We synthesized a novel type of anatase-type TiO₂-C hybrid aerogel by a one-pot sol-gel method, which shows a photocatalytic activity for methylene degradation up to 4.23 times that of P25, a commercial photocatalyst from Degussa Inc. The hybrid aerogels are prepared from TiCl₄ and resorcinol-furfural, and have a tunable macropore size from 167 to 996 nm. They are formed of submicrometer particles that consist of interwoven anatase and carbon nanoparticles. The anatase nanoparticles have a size of 8-9 nm and a tunable oxygen vacancy from 7.2 to 18.0%. The extremely high activity is ascribed to the large light absorption caused by macropore scattering and oxygen vacancies in the anatase. These findings may open up a new avenue and stimulate further research to improve photocatalytic performance.

  3. Enhanced photocatalytic activity of TiO2-C hybrid aerogels for methylene blue degradation

    PubMed Central

    Shao, Xia; Lu, Wencong; Zhang, Rui; Pan, Feng

    2013-01-01

    Carbon-based TiO2 composites have many advantages as photocatalysts. However, they suffer from low light efficiency due to the low contrast of TiO2 with carbon. We synthesized a novel type of anatase-type TiO2-C hybrid aerogel by a one-pot sol-gel method, which shows a photocatalytic activity for methylene degradation up to 4.23 times that of P25, a commercial photocatalyst from Degussa Inc. The hybrid aerogels are prepared from TiCl4 and resorcinol–furfural, and have a tunable macropore size from 167 to 996 nm. They are formed of submicrometer particles that consist of interwoven anatase and carbon nanoparticles. The anatase nanoparticles have a size of 8–9 nm and a tunable oxygen vacancy from 7.2 to 18.0%. The extremely high activity is ascribed to the large light absorption caused by macropore scattering and oxygen vacancies in the anatase. These findings may open up a new avenue and stimulate further research to improve photocatalytic performance. PMID:24145581

  4. Study on the Effect of the Three-Dimensional Electrode in Degradation of Methylene Blue by Lithium Modified Rectorite

    PubMed Central

    Huang, Jian; Du, Ying; Wang, Yingru; Wang, Ci'en

    2016-01-01

    This study presents the electrochemical degradation of methylene blue (MB) wastewater in a synthetic solution using three-dimensional particle electrodes. The novel particle electrodes were fabricated in this work using the lithium modified rectorite (Li-REC). The adsorption property of the fabricated particle electrodes was studied in a series of experiments. The optimum electrochemical operating conditions of plate distance, cell voltage, and concentration of electrolyte were 2 cm, 9 V, and 0.06 mol L−1, respectively. It was also found that microwave irradiation can effectively improve the adsorption property and electrical property of the fabricated electrodes. In addition, the scanning electron microscope (SEM) of the fabricated electrodes was investigated. The experimental results revealed the order of adsorption property and electrical property of the fabricated electrodes. So, fabricated electrodes are not only of low cost and mass produced, but also efficient to achieve decolorization of MB solution. PMID:27974993

  5. Visible light photo-degradation of methylene blue over Fe or Cu promoted ZnO nanoparticles.

    PubMed

    Mardani, Hamid Reza; Forouzani, Mehdi; Ziari, Mitra; Biparva, Pourya

    2015-04-15

    CuxZn(1-x)O, FexZn(1-x)O (x=0.01) and ZnO nanoparticles were and were characterized by X-ray diffraction, ultraviolet and visible spectroscopy, FTIR spectroscopy and SEM. The photodegradation of an aqueous solution of methylene blue (as an organic pollutant) by nanoparticles with H2O2 (30%) under visible light and the progress of the reaction were monitored by UV-Vis spectroscopy absorption. The photocatalytic oxidation efficiency of all nanoparticles was 100% at the appropriate time. The degradation time was 90 min for FeZnO, 120 min for CuZnO and 210 min for ZnO. This indicates that the photocatalytic activity of the doped nanoparticles was better than that of ZnO alone. ZnO doped with a small amount of Fe or Cu decreased the size of the nanoparticles and the band gap and increased photocatalytic efficiency.

  6. Photocatalytic activity and photocorrosion of atomic layer deposited ZnO ultrathin films for the degradation of methylene blue.

    PubMed

    Cao, Yan-Qiang; Chen, Jun; Zhou, Hang; Zhu, Lin; Li, Xin; Cao, Zheng-Yi; Wu, Di; Li, Ai-Dong

    2015-01-16

    ZnO ultrathin films with varied thicknesses of 7-70 nm were prepared at 200 °C on Si and fused quartz substrates by atomic layer deposition (ALD). The impact of film thickness and annealing temperature on the crystallinity, morphology, optical bandgap, and photocatalytic properties of ZnO in the degradation of methylene blue (MB) dye under UV light irradiation (λ = 365 nm) has been investigated deeply. The as-deposited 28 nm thick ZnO ultrathin film exhibits highest photocatalytic activity, ascribed to the smallest band gap of 3.21 eV and proper thickness. The photocorrosion effect of ALD ZnO ultrathin films during photocatalytic process is observed. The presence of MB significantly accelerates the dissolution of ZnO ultrathin films. The possible photoetching mechanism of ZnO in MB solution is proposed.

  7. Degradation of methylene blue: optimization of operating condition through a statistical technique and environmental estimate of the treated wastewater.

    PubMed

    Zhuo, Qiongfang; Ma, Hongzhu; Wang, Bo; Fan, Fang

    2008-05-01

    FeO(x)-MoO(3)-P(2)O(5) (x=1 or 1.5) composite catalyst was prepared by solid reaction method and characterized by X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). Its catalytic activities on degradation of a heteropolyaromatic dye, methylene blue (MB), were also investigated under mild condition. In order to determine the optimum operating condition, the orthogonal experiments were devised. And the results revealed that initial concentration of MB was the key factor that affected the decoloration, while the catalysts dose has an insignificant effect. Environmental estimation was also done and the results showed that the treated wastewater have little influence on plant growth and could totally be applied to irrigation.

  8. Study on the Effect of the Three-Dimensional Electrode in Degradation of Methylene Blue by Lithium Modified Rectorite.

    PubMed

    Huang, Jian; Ming, Yin'an; Du, Ying; Wang, Yingru; Wang, Ci'en

    2016-01-01

    This study presents the electrochemical degradation of methylene blue (MB) wastewater in a synthetic solution using three-dimensional particle electrodes. The novel particle electrodes were fabricated in this work using the lithium modified rectorite (Li-REC). The adsorption property of the fabricated particle electrodes was studied in a series of experiments. The optimum electrochemical operating conditions of plate distance, cell voltage, and concentration of electrolyte were 2 cm, 9 V, and 0.06 mol L(-1), respectively. It was also found that microwave irradiation can effectively improve the adsorption property and electrical property of the fabricated electrodes. In addition, the scanning electron microscope (SEM) of the fabricated electrodes was investigated. The experimental results revealed the order of adsorption property and electrical property of the fabricated electrodes. So, fabricated electrodes are not only of low cost and mass produced, but also efficient to achieve decolorization of MB solution.

  9. Comparison of ultrasonic degradation rates constants of methylene blue at 22.8 kHz, 127 kHz, and 490 kHz.

    PubMed

    Kobayashi, Daisuke; Honma, Chiemi; Suzuki, Atsushi; Takahashi, Tomoki; Matsumoto, Hideyuki; Kuroda, Chiaki; Otake, Katsuto; Shono, Atsushi

    2012-07-01

    Techniques such as solvent extraction, incineration, chemical dehalogenation, and biodegradation have been investigated for the degradation of hazardous organic compounds. We found ultrasound to be an attractive technology for the degradation of hazardous organic compounds in water. However, the effects of ultrasonic frequency on degradation rate constants were not investigated quantitatively. In this study, the degradation process of a model for hazardous organic compound methylene blue was investigated using ultrasonic irradiation. The study focused on the effects of ultrasonic frequency and ultrasonic power on the degradation rate constant. The apparent degradation rate constants were estimated based on time dependence of methylene blue concentration assuming pseudo-first-order kinetics for the decomposition. A linear relationship between the apparent degradation rate constant and ultrasonic power was identified. In addition, the apparent degradation rate constants at frequencies of 127 and 490 kHz were much larger than those at 22.8 kHz. A relationship between the apparent degradation rate constant and the sonochemical efficiency value (SE value) was also found. Based on these results, a simple model for estimating the apparent degradation rate constant of methylene blue based on the ultrasonic power and the SE value is proposed in this study.

  10. Magnetic α-Fe2O3/MCM-41 nanocomposites: preparation, characterization, and catalytic activity for methylene blue degradation.

    PubMed

    Ursachi, Irina; Stancu, Alexandru; Vasile, Aurelia

    2012-07-01

    Catalysts based on nanosized magnetic iron oxide stabilized inside the pore system of ordered mesoporous silica MCM-41 have been prepared. The obtained materials were characterized by powder X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), and N(2) adsorption-desorption isotherm. XRD analysis showed that the obtained materials consist from the pure hematite crystalline phase (α-Fe(2)O(3)) dispersed within ordered mesoporous silica MCM-41. Magnetic measurements show that the obtained nanocomposites exhibit at room temperature weak ferromagnetic behavior with slender hysteresis. The catalytic activity of the magnetic α-Fe(2)O(3)/MCM-41 nanocomposites was evaluated by the degradation of methylene blue (MB) aqueous solution. For this purpose, an ultrasound-assisted Fenton-like process was used. The effect of solution pH on degradation of MB was investigated. The results indicated that US-H(2)O(2)-α-Fe(2)O(3)/MCM-41 nanocomposite system is effective for the degradation of MB, suggesting its great potential in removal of dyes from wastewater. It was found that the degradation rate of MB increases with decrease in the pH value of the solution.

  11. Crystal Structure and Photocatalytic Activity of Al-Doped TiO2 Nanofibers for Methylene Blue Dye Degradation.

    PubMed

    Lee, Deuk Yong; Lee, Myung-Hyun; Kim, Bae-Yeon; Cho, Nam-Ihn

    2016-05-01

    Al-TiO2 nanofibers were prepared using a sol-gel derived electrospinning by varying the Al/Ti molar ratio from 0 to 0.73 to investigate the effect of Al doping on the crystal structure and the photocatalytic activity of Al-TiO2 for methylene blue (MB) degradation. XRD results indicated that as the Al/Ti molar ratio rose, crystal structure of Al-TiO2 was changed from anatase/rutile (undoped), anatase (0.07-0.18), to amorphous phase (0.38-0.73), which was confirmed by XPS and Raman analysis. The degradation kinetic constant increased from 7.3 x 10(-4) min(-1) to 4.5 x 10(-3) min(-1) with the increase of Al/Ti molar ratios from 0 to 0.38, but decreased to 3.4 x 10(-3) min(-1) when the Al/Ti molar ratio reached 0.73. The Al-TiO2 catalyst doped with 0.38 Al/Ti molar ratio demonstrated the best MB degradation. Experimental results indicated that the Al doping in Al-TiO2 was mainly attributed to the crystal structure of TiO2 and the photocatalytic degradation of MB.

  12. Photocatalytic degradation of methylene blue and inactivation of gram-negative bacteria by TiO2 nanoparticles in aqueous suspension

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The photocatalytic degradation of methylene blue (MB) and inactivation of Gram-negative bacteria E. coli K12 and P. aeruginosa by TiO2 nanoparticles in aqueous suspension were studied. TiO2 resulted in significant reduction in MB absorption and a shift of MB absorption peak from 664 nm to 658 nm aft...

  13. Effects of particle size of TiO{sub 2} on photocatalytic degradation of methylene blue in aqueous suspensions

    SciTech Connect

    Xu, N.; Shi, Z.; Fan, Y.; Dong, J.; Shi, J.; Hu, M.Z.C.

    1999-02-01

    The influence of particle size of TiO{sub 2} on the photocatalytic degradation of methylene blue (MB) in a suspended aqueous solution has been studied. The results suggested that the adsorption rate and adsorbability of MB on suspended TiO{sub 2} particles increased as the particle sizes of TiO{sub 2} decreased. Photocatalytic activity of TiO{sub 2} also increased as the particle size of TiO{sub 2} became smaller, especially when the particle size is less than 30 nm. The half-life (t{sub 0.5}) of the photocatalytic degradation of MB also decreased as the particle sizes of TiO{sub 2} decreased. The first-order reaction rate constant for photodegradation of MB increased as the particle size of TiO{sub 2} decreased. The initial degradation rate of MB in a suspended model was higher than that of a fixed-bed model. This will overcome the difficulty of preparation of ultrafine TiO{sub 2} catalyst particles. Once the problem of separation of fine TiO{sub 2} particles is solved, a TiO{sub 2} suspended photoreactor could be provided on an industrial basis.

  14. Photocatalytic degradation of methylene blue and inactivation of pathogenic bacteria using silver nanoparticles modified titanium dioxide thin films.

    PubMed

    Ibrahim, Haytham M M

    2015-07-01

    Titanium dioxide (TiO2) is a well-studied photocatalyst that is known to break down organic molecules upon ultraviolet irradiation. TiO2 thin films were fabricated on glass substrates using the doctor-blade procedure, the film surface was modified with silver nanoparticles to increase its visible light response. The Ag-TiO2 films were characterized by transmission electron microscopy, scanning electron microscopy equipped with energy dispersive spectrometry and X-ray diffraction. The photocatalytic degradation of methylene blue (MB) and inactivation of Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus were studied. The modified films presented enhanced photocatalytic efficiency and can decompose MB solution two-times faster than the unmodified TiO2 films, under illumination of sunlight. A nominal degradation (15 %) was observed in control MB under sunlight. The degradation efficiency of Ag-TiO2 films slightly decreased after five consecutive experiments. Ag-TiO2 films revealed very effective bactericidal activity against both E. coli and S. aureus. The photocatalytic inactivation toward E. coli and S. aureus showed a similar trend with much higher effectiveness toward E. coli under the same experimental conditions. The inactivation efficiency was maximized and reached 95 % for S. aureus and 97 % for E. coli, after 180 min incubation. These results demonstrate the potential of application of Ag-TiO2 photocatalysis as a method for treatment of diluted waste waters in textile industries.

  15. Enhanced Photocatalytic Performance of the Graphene-V2O5 Nanocomposite in the Degradation of Methylene Blue Dye under Direct Sunlight.

    PubMed

    Shanmugam, Mahalingam; Alsalme, Ali; Alghamdi, Abdulaziz; Jayavel, Ramasamy

    2015-07-15

    A simple and efficient solution mixing method has been developed for the synthesis of the G-V2O5 nanocomposite. By this method, one-dimensional V2O5 rods are decorated onto the two-dimensional graphene sheets. The synthesized nanocomposites are characterized by XRD, SEM with elemental mapping, TEM, FT-IR, Raman, BET, and XPS analyses. The photocatalytic activity of the G-V2O5 nanocomposite studied with methylene blue dye shows strong degradation efficiency with direct sunlight irradiation compared to UV and visible light sources. The mechanism of methylene blue dye degradation by the G-V2O5 nanocomposite has been elucidated through the kinetics of the degradation process by calculating the rate constant and half-life time of the degradation process.

  16. Superhydrophilic and Highly Transparent TiO2 Films Prepared by Dip Coating for Photocatalytic Degradation of Methylene Blue.

    PubMed

    Zhang, Hong; Liu, Yinchun; Wu, Yibing; Ruan, Kaibin

    2015-03-01

    Nanocrystalline TiO2 films were prepared on slide glass by sol-gel and dip-coating methods, and the samples were then annealed at 200 °C, 250 °C, 300 °C, 350 °C, 400 °C, 450 °C and 500 °C for 2 h. The samples' crystal structures, morphology, water contact angle, transmission spectra, and photocatalytic performance with respect to the degradation of methylene blue (MB) under UV light irradiation were characterized by X-ray diffraction spectroscopy, scanning electron microscopy, contact angle measurement, and UV-vis spectrophotometry. The results obtained indicate that all of the films were highly transparent to the visible spectrum, but with an increase in the annealing temperature, the optical band-gap and the water contact angle both reduced. Samples annealed at 450 °C and 500 °C exhibited superhydrophilic properties, with the hydrophilicity of the films remaining stable for at least 6 months without UV light irradiation. Among all the samples, the one annealed at 450 °C was found to have the highest maximum MB degradation rate of 71.1%.

  17. Titania modified activated carbon prepared from sugarcane bagasse: adsorption and photocatalytic degradation of methylene blue under visible light irradiation.

    PubMed

    El-Salamony, R A; Amdeha, E; Ghoneim, S A; Badawy, N A; Salem, K M; Al-Sabagh, A M

    2017-03-01

    Activated carbon (AC), prepared from sugarcane bagasse waste through a low-temperature chemical carbonization treatment, was used as a support for nano-TiO2. TiO2 supported on AC (xTiO2-AC) catalysts (x = 10, 20, 50, and 70 wt.%) were prepared through a mechano-mixing method. The photocatalysts were characterized by Raman, X-ray diffraction analysis, FTIR, SBET, field emission scanning electron microscope, and optical technique. The adsorption and photo-activity of the prepared catalysts (xTiO2-AC) were evaluated using methylene blue (MB) dye. The photocatalytic degradation of MB was evaluated under UVC irradiation and visible light. The degradation percentage of the 100 ppm MB at neutral pH using 20TiO2-AC reaches 96 and 91 after 180 min under visible light and UV irradiation, respectively. In other words, these catalysts are more active under visible light than under UV light irradiation, opening the possibility of using solar light for this application.

  18. Degradation of methylene blue with H2O2 activated by peroxidase-like Fe3O4 magnetic nanoparticles.

    PubMed

    Jiang, Jizhou; Zou, Jing; Zhu, Lihua; Huang, Lei; Jiang, Haipeng; Zhang, Yuanxiao

    2011-06-01

    Fe3O4 magnetic nanoparticles (Fe3O4 MNPs) were successfully prepared through an advanced reverse co-precipitation method under the assistance of ultrasound irradiation. The structure and size distribution were characterized by X-ray powder diffraction (XRD), laser particle size analyzer (LPSA), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The magnetic properties of Fe3O4 nanoparticles were measured by the vibrating sample magnetometer (VSM). Such Fe3O4 MNPs were used as a peroxidase mimetic to remove the dye pollutant methylene blue (MB) in the presence of H2O2. Some important reaction parameters were optimized to improve the degradation of MB. It was observed that the degradation efficiency of 10 mg L(-1) MB was above 96% over 0.62 g L(-1) Fe3O4 MNPs within 0.30 mmol L(-1) H2O2 at pH 4.85 and temperature 25 degrees C in 15 min, being superior to the previous reports.

  19. Synthesis of cyclotriphosphazene-containing polymeric nanotubes and their use as metal-free photocatalysts for methylene blue degradation

    NASA Astrophysics Data System (ADS)

    Li, Zhenke; Wang, Guanghui; Liang, Chen; Zhang, Aiqing

    2015-08-01

    Highly cross-linked, organic-inorganic hybrid polymer nanotubes with primary amine groups on the surface have been successfully prepared through a facile polycondensation of hexachlorocyclotriphosphazene and melamine in absence of any surfactants or template agents. Then, these nanotubes were used as visible light photocatalysts for the degradation of methylene blue (MB) in water and the physicochemical properties of catalysts were characterized by several techniques. The as-synthesized nanotubes were closed at one end with a micrometer-scale in length (about 3-10 μm), 200-300 nm in the diameter, and the inner diameters of the two ends of each nanotube was 100-200 nm and 5-10 nm, respectively. A large amount of free radicals (rad OH) were generated in aqueous phase under visible light irradiation, which can photocatalytically oxidize and eventually mineralize. And, the progress of degradation was similar with semiconductor materials. The simple preparation method and photocatalytic performance of the cyclotriphosphazene-containing polymeric nanotubes represent an important step towards photocatalytic reaction in general where artificial conjugated polymer semiconductors can be used as energy transducers.

  20. Electrocatalytic degradation of methylene blue on PbO2-ZrO2 nanocomposite electrodes prepared by pulse electrodeposition.

    PubMed

    Yao, Yingwu; Zhao, Chunmei; Zhao, Manman; Wang, Xiao

    2013-12-15

    PbO2-ZrO2 nanocomposite electrodes (P) were prepared by pulse electrodeposition and used for the electrocatalytic degradation of methylene blue (MB). The SEM and XRD tests show that PbO2-ZrO2 nanocomposite electrodes (P) possess more compact structure and finer grain size than PbO2-ZrO2 nanocomposite electrodes (D) prepared by direct electrodeposition. The electrochemical measurements show that PbO2-ZrO2 nanocomposite electrodes (P) have higher oxygen evolution overpotential and the oxidation regions of MB and water are significantly separated. The experimental parameters on electrocatalytic degradation of MB by PbO2-ZrO2 nanocomposite electrodes (P) were evaluated, such as initial MB concentration, current density, pH value and supporting electrolyte concentration. The results indicate that MB and COD removal efficiency of PbO2-ZrO2 nanocomposite electrodes (P) reach 100% and 72.7%, respectively, after 120 min electrolysis at initial 30 mg L(-1) MB concentration at current density of 50 mA cm(-2) in 0.2 mol L(-1) Na2SO4 supporting electrolyte solution, and the degradation of MB follows pseudo-first-order kinetics. Compared with PbO2-ZrO2 nanocomposite electrodes (D), PbO2-ZrO2 nanocomposite electrodes (P) show higher COD removal efficiency and instantaneous current efficiency with MB degradation. The experimental results demonstrate that PbO2-ZrO2 nanocomposite electrodes (P) possesses the excellent electrocatalytic properties and show great potential applications in refractory pollutants.

  1. Visible light-induced degradation of methylene blue in the presence of photocatalytic ZnS and CdS nanoparticles.

    PubMed

    Soltani, Nayereh; Saion, Elias; Hussein, Mohd Zobir; Erfani, Maryam; Abedini, Alam; Bahmanrokh, Ghazaleh; Navasery, Manizheh; Vaziri, Parisa

    2012-09-25

    ZnS and CdS nanoparticles were prepared by a simple microwave irradiation method under mild conditions. The obtained nanoparticles were characterized by XRD, TEM and EDX. The results indicated that high purity of nanosized ZnS and CdS was successfully obtained with cubic and hexagonal crystalline structures, respectively. The band gap energies of ZnS and CdS nanoparticles were estimated using UV-visible absorption spectra to be about 4.22 and 2.64 eV, respectively. Photocatalytic degradation of methylene blue was carried out using physical mixtures of ZnS and CdS nanoparticles under a 500-W halogen lamp of visible light irradiation. The residual concentration of methylene blue solution was monitored using UV-visible absorption spectrometry. From the study of the variation in composition of ZnS:CdS, a composition of 1:4 (by weight) was found to be very efficient for degradation of methylene blue. In this case the degradation efficiency of the photocatalyst nanoparticles after 6 h irradiation time was about 73% with a reaction rate of 3.61 × 10-3 min-1. Higher degradation efficiency and reaction rate were achieved by increasing the amount of photocatalyst and initial pH of the solution.

  2. Visible Light-Induced Degradation of Methylene Blue in the Presence of Photocatalytic ZnS and CdS Nanoparticles

    PubMed Central

    Soltani, Nayereh; Saion, Elias; Hussein, Mohd Zobir; Erfani, Maryam; Abedini, Alam; Bahmanrokh, Ghazaleh; Navasery, Manizheh; Vaziri, Parisa

    2012-01-01

    ZnS and CdS nanoparticles were prepared by a simple microwave irradiation method under mild conditions. The obtained nanoparticles were characterized by XRD, TEM and EDX. The results indicated that high purity of nanosized ZnS and CdS was successfully obtained with cubic and hexagonal crystalline structures, respectively. The band gap energies of ZnS and CdS nanoparticles were estimated using UV-visible absorption spectra to be about 4.22 and 2.64 eV, respectively. Photocatalytic degradation of methylene blue was carried out using physical mixtures of ZnS and CdS nanoparticles under a 500-W halogen lamp of visible light irradiation. The residual concentration of methylene blue solution was monitored using UV-visible absorption spectrometry. From the study of the variation in composition of ZnS:CdS, a composition of 1:4 (by weight) was found to be very efficient for degradation of methylene blue. In this case the degradation efficiency of the photocatalyst nanoparticles after 6 h irradiation time was about 73% with a reaction rate of 3.61 × 10−3 min−1. Higher degradation efficiency and reaction rate were achieved by increasing the amount of photocatalyst and initial pH of the solution. PMID:23202896

  3. TiO₂ (rutile) embedded inulin--A versatile bio-nanocomposite for photocatalytic degradation of methylene blue.

    PubMed

    Jayanthi Kalaivani, G; Suja, S K

    2016-06-05

    Inulin, a water soluble carbohydrate polymer, was extracted from Allium sativum L. by hot water diffusion method. A novel bio-nanocomposite was prepared by embedding TiO2 (rutile) onto the inulin matrix. The extracted inulin and the prepared bio-nanocomposite were characterized using UV-vis, FT-IR, XRD, SEM, TEM and TGA techniques. The photocatalytic activity of the bio-nanocomposite for the degradation of methylene blue was studied under UV illumination in batch mode experiment and was found to be twice as high as that of pristine TiO2. The kapp for inulin-TiO2 (0.0449 min(-1)) was higher than that for TiO2 (0.0325 min(-1)) which may be due to the synergistic action of inulin and TiO2. The stabilization of photo excited electron suppressed the electron-hole pair recombination thereby inducing the electrons and the holes to participate in the photo reduction and oxidation processes, respectively and enhancing the photocatalytic activity.

  4. Adsorption and photocatalytic degradation of methylene blue over hydrogen-titanate nanofibres produced by a peroxide method.

    PubMed

    El Saliby, Ibrahim; Erdei, Laszlo; Kim, Jong-Ho; Shon, Ho Kyong

    2013-08-01

    In this study, Degussa P25 TiO2 was partially dissolved in a mixture of hydrogen peroxide and sodium hydroxide at high pH. The fabrication of nanofibres proceeded by the hydrothermal treatment of the solution at 80 °C. This was followed by acid wash in HCl at pH 2 for 60 min, which resulted in the formation of hydrogen-titanate nanofibres. The nanofibres were annealed at 550 °C for 6 h to produce crystalline anatase nanofibres. The nanofibres were characterised for physico-chemical modifications and tested for the adsorption and photocatalytic degradation of methylene blue as a model water pollutant. An average specific surface area of 31.54 m(2)/g, average pore volume of 0.10 cm(3)/g and average pore size of 50 Å were recorded. The nanofibres were effective adsorbents of the model pollutant and adsorbents and good photocatalysts under simulated solar light illumination. No reduction in photocatalytic activity was observed over three complete treatment cycles, and the effective separation of nanofibres was achieved by gravity settling resulting in low residual solution turbidity.

  5. Monodisperse raspberry-like multihollow polymer/Ag nanocomposite microspheres for rapid catalytic degradation of methylene blue.

    PubMed

    Tian, Qiong; Yu, Xiaojing; Zhang, Lifeng; Yu, Demei

    2017-04-01

    Raspberry-like multihollow polymer microspheres were prepared by seeded swelling polymerization and decorated with silver nanoparticles (AgNPs) in the presence of polyvinylpyrrolidone (PVP) which acted as both reducing and stabilizing agent. Formation mechanism of the raspberry-like multihollow microsphere was discussed on the basis of water absorption of sulfonated groups in the seeded swelling polymerization. Effects of weight ratio of sodium 4-vinylbenzenesulfonate to styrene (NaSS/St) of the seed particles, the concentration of PVP and [Ag(NH3)2](+) ions on the properties of polymer/Ag nanocomposite microspheres were investigated by microscopic observation, nitrogen adsorption/desorption isotherms, UV-vis absorption spectra, X-ray diffraction patterns and thermogravimetric analysis. The results demonstrated that the raspberry-like multihollow microspheres were successfully fabricated by controlling over the NaSS/St of the seed particles in the seeded swelling polymerization by which the fabrication of hollow structure became simple and convenient. The spherical AgNPs were loaded on the polymer microsphere by in-situ chemical reduction due to the stabilization and reduction of PVP and the attraction between sulfonated groups and [Ag(NH3)2](+) ions. The raspberry-like multihollow polymer/Ag microspheres showed good catalytic activity and reusability in the degradation of methylene blue in the presence of NaBH4.

  6. Fenton-like degradation of Methylene Blue using paper mill sludge-derived magnetically separable heterogeneous catalyst: Characterization and mechanism.

    PubMed

    Zhou, Guoqiang; Chen, Ziwen; Fang, Fei; He, Yuefeng; Sun, Haili; Shi, Huixiang

    2015-09-01

    For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst (PMS-Fe-380) was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer-Emmet-Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue (MB). The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover, leaching tests indicated that the leached iron is negligible (<0.5mg/L). This study provides an alternative environmentally friendly reuse method for paper mill sludge and a novel catalyst PMS-Fe-380 that can be considered as a promising heterogeneous Fenton-like catalyst.

  7. Facile synthesis of Au-ZnO plasmonic nanohybrids for highly efficient photocatalytic degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Kuriakose, Sini; Sahu, Kavita; Khan, Saif A.; Tripathi, A.; Avasthi, D. K.; Mohapatra, Satyabrata

    2017-02-01

    Au-ZnO plasmonic nanohybrids were synthesized by a facile two step process. In the first step, nanostructured ZnO thin films were prepared by carbothermal evaporation followed by thermal annealing in oxygen atmosphere. Deposition of ultrathin Au films onto the nanostructured ZnO thin films by sputtering combined with thermal annealing resulted in the formation of Au-ZnO plasmonic nanohybrid thin films. The structural, optical, plasmonic and photocatalytic properties of the Au-ZnO nanohybrid thin films were studied. XRD studies on the Au-ZnO hybrid thin films revealed the presence of Au and ZnO nanostructures. UV-visible absorption studies showed two peaks corresponding to the excitonic absorption of ZnO nanostructures in the UV region and the surface plasmon resonance (SPR) absorption of Au nanoparticles in the visible region. The Au-ZnO nanohybrid thin films annealed at 400 °C showed enhanced photocatalytic activity as compared to nanostructrured ZnO thin films towards sun light driven photocatalytic degradation of methylene blue (MB) dye in water. The observed enhanced photocatalytic activity of Au-ZnO plasmonic nanohybrids is attributed to the efficient suppression of the recombination of photogenerated charge carriers in ZnO due to the strong electron scavenging action of Au nanoparticles combined with the improved sun light utilization capability of Au-ZnO nanohybrids coming from the plasmonic response of Au nanoparticles decorating ZnO nanostructures.

  8. Tubular structured hierarchical mesoporous titania material derived from natural cellulosic substances and application as photocatalyst for degradation of methylene blue

    SciTech Connect

    Huang, Haiqing; Liu, Xiaoyan; Huang, Jianguo

    2011-11-15

    Graphical abstract: Bio-inspired, tubular structured hierarchical mesoporous titania material with high photocatalytic activity under UV light was fabricated employing natural cellulosic substance (cotton) as hard template and cetyltrimethylammonium bromide (CTAB) surfactant as soft template using a one-pot sol-gel method. Highlights: {yields} Tubular structured mesoporous titania material was fabricated by sol-gel method. {yields} The titania material faithfully recorded the hierarchical structure of the template substrate (cotton). {yields} The titania material exhibited high photocatalytic activity in decomposition of methylene blue. -- Abstract: Bio-inspired, tubular structured hierarchical mesoporous titania material was designed and fabricated employing natural cellulosic substance (cotton) as hard template and cetyltrimethylammonium bromide (CTAB) surfactant as soft template by one-pot sol-gel method. The tubular structured hierarchical mesoporous titania material processes large specific surface area (40.23 m{sup 2}/g) and shows high photocatalytic activity in the photodegradation of methylene blue under UV light irradiation.

  9. Photocatalytic degradation of methylene blue on Sn-doped titania nanoparticles synthesized by solution combustion route

    SciTech Connect

    Bhange, P.D.; Awate, S.V.; Gholap, R.S.; Gokavi, G.S.; Bhange, D.S.

    2016-04-15

    Highlights: • Series of Sn-doped titania nanoparticles were prepared by solution combustion synthesis method. • Sn-doped titania nanoparticles were tested for degradation of MB under UV light irradiation. • The maximum Sn doping in the TiO{sub 2} lattice is found to be less than 10%. • The crystallite size decreases with increase in the Sn content. • The doping of Sn into TiO{sub 2} lattice hinders the recombination of electrons and holes thus enhance the photocatalytic activity. - Abstract: Series of tin-doped titania nanoparticles with varying tin content in the range 0–20 mol% have been prepared by solution combustion synthesis route using urea as a fuel. The structure, surface morphology and optical activity of Sn-doped TiO{sub 2} nanoparticles were investigated by various analytical techniques such as powder XRD, SEM, TEM, UV–vis and N{sub 2} adsorption study. The crystalline structures of the various phases were studied by rietveld refinement of the XRD data. The photocatalytic performance of Sn-doped titania nanoparticles were tested for degradation of MB under UV and visible light irradiation. The results reveal that the photocatalytic activity increases with increase in tin content which may be due to decrease in crystallite size with increase in surface area. The doping of Sn into TiO{sub 2} lattice hinders the recombination of electrons and holes thus enhance the quantum efficiency of photocatalytic reaction.

  10. Sol–gel synthesis of SnO{sub 2}–MgO nanoparticles and their photocatalytic activity towards methylene blue degradation

    SciTech Connect

    Bayal, Nisha; Jeevanandam, P.

    2013-10-15

    Graphical abstract: - Highlights: • A simple sol–gel method for the synthesis of SnO{sub 2}–MgO nanoparticles is reported. • Band gap of SnO{sub 2} can be tuned by varying the magnesium content in SnO{sub 2}–MgO. • SnO{sub 2}–MgO shows good photocatalytic activity towards degradation of methylene blue. - Abstract: SnO{sub 2}–MgO mixed metal oxide nanoparticles were prepared by a simple sol–gel method. The nanoparticles were characterized by power X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The XRD results indicate the formation of mixed metal oxide nanoparticles and also a decrease of SnO{sub 2} crystallite size in the mixed metal oxide nanoparticles with increasing magnesium oxide content. The reflectance spectroscopy results show a blue shift of the band gap of SnO{sub 2} in the mixed metal oxide nanoparticles. The photocatalytic activity of the SnO{sub 2}–MgO nanoparticles was tested using the photodegradation of aqueous methylene blue in the presence of sunlight. The results indicate that the mixed metal oxide nanoparticles possess higher efficiency for the photodegradation of methylene blue compared to pure SnO{sub 2} nanoparticles.

  11. Photocatalytic degradation of methylene blue dye from aqueous solution using silver ion-doped TiO₂ and its application to the degradation of real textile wastewater.

    PubMed

    Sahoo, Chittaranjan; Gupta, Ashok K; Sasidharan Pillai, Indu M

    2012-01-01

    Methylene blue dye (MB) was degraded photocatalytically in aqueous solution using Ag(+) doped TiO(2) under UV irradiation. The degradations of the dye using untreated TiO(2) and Ag(+) doped TiO(2) were compared. Ag(+) doped TiO(2) was found to be more efficient. Using Ag(+) doped TiO(2) the filtration process was eliminated, as the particles became more settleable. The effect of various parameters such as catalyst loading, initial dye concentration, depth of solution, degree of adsorption, pH and O(2) on dye degradation was studied. The extent of mineralization was studied by observing the COD removal at different time intervals. The effects of various interfering ions such as Cl(-), NO(3) (-), CO(3) (2-), SO(4) (2-), Ca(2+) and Fe(3+) and electron acceptors such as H(2)O(2), KBrO(3) and (NH(4))(2)S(2)O(8) on the dye degradation was also studied. The degradation kinetics fitted well to Langmuir-Hinshelwood pseudo first order rate law. An aqueous solution of MB (20ppm) degraded by more than 99% after UV irradiation for 180 min with Ag(+) doped TiO(2) (2 g/L) and by more than 95% with untreated TiO(2) (2 g/L)(.) The COD removal was more than 91% with Ag(+)doped TiO(2) and more than 86% with untreated TiO(2) after 240 min. The degradation and COD removal of 5 times diluted textile wastewater was more than 98% and 79% respectively with 1 g/L Ag(+) doped TiO(2) after UV irradiation for 420 min.

  12. Efficient degradation of Methylene Blue dye over highly reactive Cu doped strontium titanate (SrTiO3) nanoparticles photocatalyst under visible light.

    PubMed

    Rahman, Qazi Inamur; Ahmad, Musheer; Misra, Sunil Kumar; Lohani, Minaxi

    2012-09-01

    Visible light induced photocatalysts of Cu doped SrTiO3 (Cu/SrTiO3) nanoparticles with the size -60-75 nm were prepared via facile sol-gel method. The morphological, optical, crystalline properties and compositions of synthesized Cu/SrTiO3 nanoparticles were thoroughly characterized by field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), ultra violet-visible spectroscopy (UV-Vis) and energy dispersive X-ray (EDX). A significant red shift in the UV-diffused reflectance spectrum was observed and the absorption edge shifted to visible region by the Cu doping. Surprisingly, the band gap of SrTiO3 was changed from 3.2 eV drop to 2.96 eV. The photocatalytic activity of the synthesized Cu/SrTiO3 nanoparticles was demonstrated for the degradation of Methylene Blue dye under visible light irradiation. The formation of new acceptor region in Cu/SrTiO3 was responsible for high photocatalytic activity of Cu/SrTiO3 nanoparticles. The results showed that the Methylene Blue dye was degraded by -66% within time span of 2 h over the Cu/SrTiO3 nanoparticles. This dye degradation reaction followed the Langmuir-Hinshelwood kinetics and also exhibited first order reaction rate. The calculated rate constant for the degradation reaction following first order kinetics was k = 0.0016 min(-1).

  13. Photocatalytic degradation efficacy of Bi4Ti3O12 micro-scale platelets over methylene blue under visible light

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Jia, Zhen; Lei, E.; Wang, Liguo; Li, Zhaoyang; Dai, Yejing

    2013-11-01

    <001> textured Bi4Ti3O12 platelets with micro scale size were synthesized by a facile molten salt method. The photocatalytic activities of the as-prepared samples were measured with the photodegradation of methylene blue at room temperature under visible light irradiation. The Bi4Ti3O12 with the aspect ratio of 35 exhibited good absorption in the visible light region and the photodegradation against methylene blue was higher than that of anatase TiO2 reference, showing that the high degree of preferred {001} facets on the plate surface benefits the electronic transmission. In addition, the layer-pervoskite structure facilitates the mobility of the photogenerated carriers and hampers their recombination. The above results indicated that the large specific surface area of the as-prepared samples could attribute to the presence of a number of oxygen vacancies and then lead to the good photo-electric property. This work proposed an alternative way to tailor the structure of micro-sized platelets to get excellent properties comparable to the nano materials.

  14. Fabrication and efficient photocatalytic degradation of methylene blue over CuO/BiVO{sub 4} composite under visible-light irradiation

    SciTech Connect

    Jiang Haiqing Endo, Hiromitsu; Natori, Hirotaka; Nagai, Masayuki; Kobayashi, Koichi

    2009-03-05

    CuO/BiVO{sub 4} composite photocatalysts were prepared by solution combustion synthesis method and impregnation technique. X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scan electron microscopy and UV-vis diffusion reflectance spectra were used to identify the physical properties and photophysical properties of CuO/BiVO{sub 4} composite photocatalysts. The photocatalysts exhibit the enhanced photocatalytic properties for degradation of methylene blue under visible-light ({lambda} > 420 nm). The mechanism of improved photocatalytic activity is also discussed.

  15. Solvothermal synthesis of V{sub 4}O{sub 9} flake-like morphology and its photocatalytic application in the degradation of methylene blue

    SciTech Connect

    Chine, M.K.; Sediri, F.; Gharbi, N.

    2012-11-15

    Highlights: ► Flake-like nanocrystalline V{sub 4}O{sub 9} was synthesized by a solvothermal route. ► Photocatalytic activity has been evaluated by the degradation of methylene blue under visible light irradiation. ► V{sub 4}O{sub 9} nanoflakes exhibited much higher photocatalytic activity two times higher than the bulk V{sub 2}O{sub 5}. -- Abstract: Flake-like nanocrystalline V{sub 4}O{sub 9} has been successfully synthesized by solvothermal process using V{sub 2}O{sub 5} as vanadium source and phenolphthalein as a reducing agent and a structure-directing template. Techniques X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and ultraviolet–visible (UV–vis) spectroscopy have been used to characterize the structure, the morphology and the composition of the material. The photocatalytic activity of the material has been evaluated by the degradation of methylene blue under visible light irradiation. As a result, after the lapse of 150 min, around 93.54% bleaching was observed, with V{sub 4}O{sub 9} nanoflakes yielding more photodegradation compared to that of bulk V{sub 2}O{sub 5}. This presents a degradation percentage of about 44.67%.

  16. Gadolinium nanoparticle-decorated multiwalled carbon nanotube/titania nanocomposites for degradation of methylene blue in water under simulated solar light.

    PubMed

    Mamba, G; Mbianda, X Y; Mishra, A K

    2014-04-01

    Gadolinium oxide nanoparticles of diameters <5 nm were uniformly decorated on the surfaces of multiwalled carbon nanotubes which were subsequently used as templates to fabricate gadolinium oxide nanoparticle-decorated multiwalled carbon nanotube/titania nanocomposites. The prepared nanocomposites were evaluated for the photocatalytic degradation of methylene blue under simulated solar light irradiation. Higher photocatalytic activity was observed for the gadolinium oxide-decorated multiwalled carbon nanotube-based nanocomposites compared to the neat multiwalled carbon nanotube/titania nanocomposite and commercial titania. This improvement in photocatalytic activity was ascribed to the gadolinium oxide nanoparticles supported at the interface of the carbon nanotubes and titania resulting in efficient electron transfer between the two components of the composite. Total organic carbon (TOC) analysis revealed a higher degree of complete mineralisation of methylene blue (80.0 % TOC removal) which minimise the possible formation of toxic by-products. The photocatalyst could be re-used for five times, reaching a maximum degradation efficiency of 85.9 % after the five cycles. The proposed photocatalytic degradation mechanism is outlined herein.

  17. Efficient degradation of methylene blue dye over tungsten trioxide/multi-walled carbon nanotube system as a novel photocatalyst

    NASA Astrophysics Data System (ADS)

    Dinari, Mohammad; Momeni, Mohamad Mohsen; Ahangarpour, Marzieh

    2016-10-01

    Combination of acid-functionalized multi-walled carbon nanotube/tungsten trioxide (MWCNT/WO3) with different MWCNT's weight percentages as visible light-induced photocatalysts for photodegradation of methylene blue (MB) dye was synthesized. These photocatalysts were characterized by Fourier transform infrared, X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, field emission scanning electron microscopy and transmission electron microscopy techniques. Their photocatalytic activities were tested by using MB as a model compound. The results show that the MWCNT/WO3 hybrid nanostructures exhibit higher photocatalytic activity than pure WO3 or MWCNTs due to their higher absorption enhancement in visible light region and effective separation of electrons and holes. The stability of the hybrid was characterized through cyclic photocatalytic test.

  18. Dual-frequency (20/40 kHz) ultrasonic assisted photocatalysis for degradation of methylene blue effluent: synergistic effect and kinetic study.

    PubMed

    Xiong, Shao Feng; Yin, Zhou Lan; Yuan, Zhang Fu; Yan, Wen Bin; Yang, Wen Yin; Liu, Jin Jian; Zhang, Fan

    2012-07-01

    Dual-frequency ultrasonic assisted photocatalysis (DUAP) was proposed to enhance the degradation efficiency of methylene blue (MB) solution. The influence of operational parameters, i.e., irradiation time, ultrasonic arrangement, TiO(2) concentration and power density, was studied. The results implied that the rapid degradation of MB solution was achieved in 18 min under DUAP with the dual frequencies of 20/40 kHz. Kinetic investigation of MB degradation for the DUAP process was conducted on the basis of first-order kinetic equation and the synergistic effect was assessed by examination of the apparent rate constant. The effect of ultrasonic arrangement was analyzed by comparison of the pressure amplitude of ultrasonic superposition field. The evolvement of intermediate products and the role of active species during DUAP were distinguished by UV-Vis spectra and the free radical scavenging experiment.

  19. One-pot green synthesis of reduced graphene oxide (RGO)/Fe3O4 nanocomposites and its catalytic activity toward methylene blue dye degradation.

    PubMed

    Vinothkannan, M; Karthikeyan, C; Gnana kumar, G; Kim, Ae Rhan; Yoo, Dong Jin

    2015-02-05

    The reduced graphene oxide (RGO)/Fe3O4 nanocomposites were synthesized through a facile one-pot green synthesis by using solanum trilobatum extract as a reducing agent. Spherical shaped Fe3O4 nanoparticles with the diameter of 18 nm were uniformly anchored over the RGO matrix and the existence of fcc structured Fe3O4 nanoparticles over the RGO matrix was ensured from X-ray diffraction patterns. The amide functional groups exist in the solanum trilobatum extract is directly responsible for the reduction of Fe(3+) ions and GO. The thermal stability of GO was increased by the removal of hydrophilic functional groups via solanum trilobatum extract and was further promoted by the ceramic Fe3O4 nanoparticles. The ID/IG ratio of RGO/Fe3O4 was increased over GO, indicating the extended number of structural defects and disorders in the RGO/Fe3O4 composite. The catalytic efficiency of prepared nanostructures toward methylene blue (MB) dye degradation mediated through the electron transfer process of BH4(-) ions was studied in detail. The π-π stacking, hydrogen bonding and electrostatic interaction exerted between the RGO/Fe3O4 composite and methylene blue, increased the adsorption efficiency of dye molecules and the large surface area and extended number of active sites completely degraded the MB dye within 12 min.

  20. Decolorization of methylene blue in aqueous suspensions of titanium peroxide.

    PubMed

    Ogino, Chiaki; Dadjour, Mahmoud Farshbaf; Iida, Yasuo; Shimizu, Nobuaki

    2008-05-01

    The pretreatment of TiO(2)-photocatalysts in solutions of H(2)O(2) was studied by examining the decolorization of methylene blue in the dark. Incubation of TiO(2) particles in H(2)O(2) solutions increased the oxidizing capacity of TiO(2). Methylene blue (0.3 mM) was degraded in the presence of pretreated TiO(2), and a decolorizing ratio of 47% was obtained after a 48-h incubation period in the presence of 5.0 g/L pretreated TiO(2). Titanium peroxide as a stable oxidant, which can be synthesized with the reaction of titanium sulfate and H(2)O(2), was studied in the decolorizing process of methylene blue. Concentrations of methylene blue were significantly reduced in the presence of titanium peroxide, and a greater extent of decolorization was obtained with larger amounts of titanium peroxide. A 63% decrease in methylene blue concentration was achieved in 5h incubation in the presence of 4.0 g/L titanium peroxide. H(2)O(2) accelerated the decolorizing process in the presence of titanium peroxide. The addition of 100 mM H(2)O(2) to a methylene blue solution containing 2.0 g/L titanium peroxide increased the decolorizing ratio to 85% after 5 h incubation. The addition of a hydroxyl radical scavenger, dimethyl sulfoxide, significantly decreased the decolorizing ratio, indicating the role of hydroxyl radicals in the oxidation process.

  1. Synthesis of TiO2/WO3 nanoparticles via sonochemical approach for the photocatalytic degradation of methylene blue under visible light illumination.

    PubMed

    Anandan, Sambandam; Sivasankar, Thirugnanasambandam; Lana-Villarreal, Teresa

    2014-11-01

    Through an ultrasound assisted method, TiO2/WO3 nanoparticles were synthesized at room temperature. The XRD pattern of as-prepared TiO2/WO3 nanoparticles matches well with that of pure monoclinic WO3 and rutile TiO2 nanoparticles. TEM images show that the prepared TiO2/WO3 nanoparticles consist of mixed square and hexagonal shape particles about 8-12nm in diameter. The photocatalytic activity of TiO2/WO3 nanoparticles was tested for the degradation of a wastewater containing methylene blue (MB) under visible light illumination. The TiO2/WO3 nanoparticles exhibits a higher degradation rate constant (6.72×10(-4)s(-1)) than bare TiO2 nanoparticles (1.72×10(-4)s(-1)) under similar experimental conditions.

  2. Zirconium and silver co-doped TiO2 nanoparticles as visible light catalyst for reduction of 4-nitrophenol, degradation of methyl orange and methylene blue

    NASA Astrophysics Data System (ADS)

    Naraginti, Saraschandra; Stephen, Finian Bernard; Radhakrishnan, Adhithya; Sivakumar, A.

    2015-01-01

    Catalytic activity of Zr and Ag co-doped TiO2 nanoparticles on the reduction of 4-nitrophenol, degradation of methylene blue and methyl orange was studied using sodium borohydride as reducing agent. The nanoparticles were characterized using X-ray diffraction, energy dispersive X-ray, high resolution transmission electron microscopy, selected area electron diffraction and UV-Vis spectroscopy. The rate of the reduction/degradation was found to increase with increasing amount of the photocatalyst which could be attributed to higher dispersity and small size of the nanoparticles. The catalytic activity of Zr and Ag co-doped TiO2 nanoparticles showed no significant difference even after recycling the catalyst four times indicating a promising potential for industrial application of the prepared photocatalyst.

  3. Zirconium and silver co-doped TiO2 nanoparticles as visible light catalyst for reduction of 4-nitrophenol, degradation of methyl orange and methylene blue.

    PubMed

    Naraginti, Saraschandra; Stephen, Finian Bernard; Radhakrishnan, Adhithya; Sivakumar, A

    2015-01-25

    Catalytic activity of Zr and Ag co-doped TiO2 nanoparticles on the reduction of 4-nitrophenol, degradation of methylene blue and methyl orange was studied using sodium borohydride as reducing agent. The nanoparticles were characterized using X-ray diffraction, energy dispersive X-ray, high resolution transmission electron microscopy, selected area electron diffraction and UV-Vis spectroscopy. The rate of the reduction/degradation was found to increase with increasing amount of the photocatalyst which could be attributed to higher dispersity and small size of the nanoparticles. The catalytic activity of Zr and Ag co-doped TiO2 nanoparticles showed no significant difference even after recycling the catalyst four times indicating a promising potential for industrial application of the prepared photocatalyst.

  4. Effect of Vanadium(IV)-Doping on the Visible Light-Induced Catalytic Activity of Titanium Dioxide Catalysts for Methylene Blue Degradation

    PubMed Central

    Lin, Wen-Churng; Lin, Yo-Jane

    2012-01-01

    Abstract Vanadium(IV)-doped titanium dioxide (TiO2) photocatalyst powders were prepared by the sol–gel method and characterized by Brunauer–Emmett–Teller–specific surface area, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy. V-doping in the TiO2 increases the crystal grain size, which decreases the specific surface areas of powders. This V-doping changes the band gap of TiO2, leading to extend the absorption to visible light regions (400–800 nm). Photocatalytic degradation of methylene blue (MB) in water was investigated as a function of the vanadium content in TiO2 and was found to follow pseudo first-order rate kinetics. Appropriate content of V-doping is an effective means to improve the photocatalytic activity of TiO2 for MB degradation under visible light irradiation. PMID:22693413

  5. Synthesis of pore-variable mesoporous CdS and evaluation of its photocatalytic activity in degrading methylene blue

    SciTech Connect

    Zhang, Wei-Min; Jiang, Yao-Quan; Cao, Xiao-Yan; Chen, Meng; Ge, Dong-Lai; Sun, Zhong-Xi

    2013-10-15

    Graphical abstract: - Highlights: • Self-templated synthesis of tubular CdS. • Cadmium complexes of aliphatic acids sustain the network of mesoporous structures. • Aliphatic acids affect the phase composition and particle size. • Pore size and volume vary with aliphatic acids having different hydrocarbonyl. - Abstract: In this study, mesoporous CdS polycrystallites have been synthesized using aliphatic acids of hexanoic acid, octanoic acid, and oleic acid as coordinating and capping agents, respectively. The fibrous Cd–fatty acid salts act as a template to form the tubular CdS. The organic species are found to be necessary for maintaining the network of mesoporous CdS. The characterization results indicate that the shorter carbon chain length in aliphatic acids favors the wurtzite phase and particle size growth the specific surface area, pore diameter and pore volume show a monotonic raise with increasing carbon chain. The photocatalytic activities of mesoporous CdS tubes exhibit much higher efficiency than those of nanosized CdS powders in decolorizing methylene blue under simulated visible light.

  6. Photocatalytic degradation of methylene blue by TiO2-Cu thin films: theoretical and experimental study.

    PubMed

    Carvalho, Hudson W P; Batista, Ana P L; Hammer, Peter; Ramalho, Teodorico C

    2010-12-15

    In this work the effect of doping concentration and depth profile of Cu atoms on the photocatalytic and surface properties of TiO(2) films were studied. TiO(2) films of about 200 nm thickness were deposited on glass substrates on which a thin Cu layer (5 nm) was deposited. The films were annealed during 1s to 100°C and 400°C, followed by chemical etching of the Cu film. The grazing incidence X-ray fluorescence measurements showed a thermal induced migration of Cu atoms to depths between 7 and 31 nm. The X-ray photoelectron spectroscopy analysis detected the presence of TiO(2), Cu(2)O and Cu(0) phases and an increasing Cu content with the annealing temperature. The change of the surface properties was monitored by the increasing red-shift and absorption of the ultraviolet-visible spectra. Contact angle measurements revealed the formation of a highly hydrophilic surface for the film having a medium Cu concentration. For this sample photocatalytic assays, performed by methylene blue discoloration, show the highest activity. The proposed mechanism of the catalytic effect, taking place on Ti/Cu sites, is supported by results obtained by theoretical calculations.

  7. Preparation of nitrogen-doped cotton stalk microporous activated carbon fiber electrodes with different surface area from hexamethylenetetramine-modified cotton stalk for electrochemical degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Li, Kunquan; Rong, Zhang; Li, Ye; Li, Cheng; Zheng, Zheng

    Cotton-stalk activated carbon fibers (CSCFs) with controllable micropore area and nitrogen content were prepared as an efficient electrode from hexamethylenetetramine-modified cotton stalk by steam/ammonia activation. The influence of microporous area, nitrogen content, voltage and initial concentration on the electrical degradation efficiency of methylene blue (MB) was evaluated by using CSCFs as anode. Results showed that the CSCF electrodes exhibited excellent MB electrochemical degradation ability including decolorization and COD removal. Increasing micropore surface area and nitrogen content of CSCF anode leaded to a corresponding increase in MB removal. The prepared CSCF-800-15-N, which has highest N content but lowest microporous area, attained the best degradation effect with 97% MB decolorization ratio for 5 mg/L MB at 12 V in 4 h, implying the doped nitrogen played a prominent role in improving the electrochemical degradation ability. The electrical degradation reaction was well described by first-order kinetics model. Overall, the aforesaid findings suggested that the nitrogen-doped CSCFs were potential electrode materials, and their electrical degradation abilities could be effectively enhanced by controlling the nitrogen content and micropore surface area.

  8. Spectroscopic and kinetic studies on the degradation of methylene blue using the supramolecular coordination polymer [(Ph3Sn)4FeCN(6)] as catalyst.

    PubMed

    Ibrahim, Amany M A; Al-Ashqar, Sawsan M A

    2012-06-15

    The structure of the supramolecular coordination polymer (SCP), [(Ph(3)Sn)(4)Fe(CN)(6)], 1, consists of octahedral [Fe(CN)(6)](4-) building blocks which are connected by the TBPY-5 configured Ph(3)Sn(CN…)(2) fragments creating 3D-network structure that contains terminal cyanide groups. The catalytic behavior of the SCP 1 was utilized for Fenton and photo-Fenton degradation of methylene blue dye (MB). The plot of kinetic degradation indicates pseudo first-order rate with respect to the MB dye concentration, K(obs.)=0.071 min(-1). On the other hand, the observed rate constant of the photo catalytic degradation of MB equals to 1.45 min(-1) indicating that irradiation enhances, significantly, the rate of degradation of MB dye. Discoloration of the dye was obtained in less than 3h. Meanwhile, the conjugated structure and the phenyl rings of the MB molecule were destroyed or even broken down into small organic acids and inorganic ions, as indicated by FT-IR spectra. Disodium salt of terephthalic acid photoluminescence probing technology and radical scavenging measurements were carried out to identify the reactive oxygen species. The different parameters that affect MB degradation rate were evaluated. Moreover, the efficiency of recycled the SCP 1 and the mechanism of degradation of MB dye was investigated.

  9. Comparison of catalytic activities for photocatalytic and sonocatalytic degradation of methylene blue in present of anatase TiO2-CNT catalysts.

    PubMed

    Zhang, Kan; Zhang, Feng Jun; Chen, Ming Liang; Oh, Won Chun

    2011-05-01

    Anatase TiO(2)-CNT catalysts with high specific surface areas were prepared by depositing TiO(2) particles on the surface of carbon nanotubes (CNTs) using a modified sol-gel technique. These catalysts prepared with different amounts of CNTs were characterized by nitrogen adsorption, Fourier Transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray (EDX) and ultraviolet-visible (UV-Vis) spectroscopy. The catalytic activity of the anatase TiO(2)-CNT catalysts was assessed by examining the degradation of methylene blue (MB) from model aqueous solutions as a probe reaction under visible light and ultrasonic irradiation. The synergistic effect of the greater surface area and catalytic activities of the composite catalysts was examined in terms of the strong adsorption ability and interphase interaction by comparing the different amounts and roles of CNTs in the catalysts.

  10. Porous Co₃O₄ nanorods-reduced graphene oxide with intrinsic peroxidase-like activity and catalysis in the degradation of methylene blue.

    PubMed

    Zhang, Zhe; Hao, Jinhui; Yang, Wenshu; Lu, Baoping; Ke, Xi; Zhang, Bailin; Tang, Jilin

    2013-05-01

    A facile two step process was developed for the synthesis of porous Co3O4 nanorods-reduced graphene oxide (PCNG) hybrid materials based on the hydrothermal treatment cobalt acetate tetrahydrate and graphene oxide in a glycerol-water mixed solvent, followed by annealing the intermediate of reduced graphene oxide-supported Co(CO3)0.5(OH)·0.11H2O nanorods in a N2 atmosphere. The morphology and microstructure of the composites were examined by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy. It is shown that the obtained PCNG have intrinsic peroxidase-like activity. The PCNG are utilized for the catalytic degradation of methylene blue. The good catalytic performance of the composites could be attributed to the synergy between the functions of porous Co3O4 nanorods and reduced graphene oxide.

  11. Influence of anatase and rutile phase in TiO2 upon the photocatalytic degradation of methylene blue under solar irradiation in presence of activated carbon.

    PubMed

    Matos, J; Montaña, R; Rivero, E; Escudero, A; Uzcategui, D

    2014-01-01

    The influence of activated carbon (AC) on the photocatalytic activity of different crystalline TiO2 phases was verified in the photocatalytic degradation of methylene blue under UV and solar irradiation. The results showed a volcano trend with a maximum photoactivity for the crystalline phase ratio of anatase:rutile equal to 80:20 both under UV or solar irradiation. By contrast, in presence of AC the photocatalytic activity of the binary materials of TiO2/AC followed an exponential trend, increasing as a function of the increase in anatase proportion in the TiO2 framework. The increase in the photoactivity of the binary material TiO2/AC relative to neat TiO2 was up to 22 and about 17 times higher under UV and visible irradiation, respectively. The present results suggest that AC interacts more efficiently with anatase phase than with rutile phase.

  12. Synthesis of Ag-ZnO with multiple rods (multipods) morphology and its application in the simultaneous photo-catalytic degradation of methyl orange and methylene blue.

    PubMed

    Arab Chamjangali, M; Bagherian, G; Javid, A; Boroumand, S; Farzaneh, N

    2015-11-05

    In this study, the photo-decolorization of a mixture of methylene blue (MB) and methyl orange (MO) was investigated using Ag-ZnO multipods. The photo-catalyst used, ZnO multipods, was successfully synthesized. The surface of ZnO microstructure was modified by deposition of different amounts of Ag nanoparticles (Ag NPs) using the photo-reduction method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis and atomic absorption spectroscopy. The photo-catalytic efficiency of Ag-ZnO is mainly controlled by the amount of Ag NPs deposited on the ZnO surface. The results obtained suggest that Ag-ZnO containing 6.5% Ag NPs, has the highest photo-catalytic performance in the simultaneous photo-degradation of dyes at a shorter time.

  13. A novel bio-degradable polymer stabilized Ag/TiO2 nanocomposites and their catalytic activity on reduction of methylene blue under natural sun light.

    PubMed

    Geetha, D; Kavitha, S; Ramesh, P S

    2015-11-01

    In the present work we defined a novel method of TiO2 doped silver nanocomposite synthesis and stabilization using bio-degradable polymers viz., chitosan (Cts) and polyethylene glycol (PEG). These polymers are used as reducing agents. The instant formation of AgNPs was analyzed by visual observation and UV-visible spectrophotometer. TiO2 nanoparticles doped at different concentrations viz., 0.03, 0.06 and 0.09mM on PEG/Cts stabilized silver (0.04wt%) were successfully synthesized. This study presents a simple route for the in situ synthesis of both metal and polymer confined within the nanomaterial, producing ternary hybrid inorganic-organic nanomaterials. The results reveal that they have higher photocatalytic efficiencies under natural sun light. The synthesized TiO2 doped Ag nanocomposites (NCs) were characterized by SEM/EDS, TEM, XRD, FTIR and DLS with zeta potential. The stability of Ag/TiO2 nanocomposite is due to the high negative values of zeta potential and capping of constituents present in the biodegradable polymer which is evident from zeta potential and FT-IR studies. The XRD and EDS pattern of synthesized Ag/TiO2 NCs showed their crystalline structure, with face centered cubic geometry oriented in (111) plane. AFM and DLS studies revealed that the diameter of stable Ag/TiO2 NCs was approximately 35nm. Moreover the catalytic activity of synthesize Ag/TiO2 NCs in the reduction of methylene blue was studied by UV-visible spectrophotometer. The synthesized Ag/TiO2 NCs are observed to have a good catalytic activity on the reduction of methylene blue by bio-degradable which is confirmed by the decrease in absorbance maximum value of methylene blue with respect to time using UV-vis spectrophotometer. The significant enhancement in the photocatalytic activity of Ag/TiO2 nanocomposites under sun light irradiation can be ascribed to the effect of noble metal Ag by acting as electron traps in TiO2 band gap.

  14. Photoelectrochemical degradation of Methylene Blue with beta-PbO2 electrodes driven by visible light irradiation.

    PubMed

    Li, Guoting; Yip, Hoyin; Wong, Kin Hang; Hu, Chun; Qu, Jiuhui; Wong, Po Keung

    2011-01-01

    Beta-PbO2 electrodes were prepared by electro-deposition and characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and linear sweep voltammetry. We confirmed pure (beta-PbO2 crystals were on the electrode and it had a high oxygen evolution potential. The photoactivity and photoelectrochemical (PEC) properties of the beta-PbO2 electrode were investigated under visible light irradiation (lambda > 420 nm) for the decolorization of Methylene Blue. Pseudo first-order kinetics parameter (K(app)) for dye decolorization using the beta-PbO2 electrode achieved 6.71 x 10(-4) min(-1) under visible light irradiation, which indicated its excellent visible light-induced photoactivity. The K(app) of the PEC process was as much as 1.41 x 10(-3) min(-1) and was 1.71 times that of visible light irradiation or electrolysis even in the presence of the beta-PbO2 electrode. A significant synergetic effect was observed in the PEC system. We also employed TiO2 modified beta-PbO2 electrodes in this test, which revealed that the TiO2 immobilized on the beta-PbO2 electrode inhibited the visible light-induced PEC efficiency despite the amount of TiO2 used for electrode preparation. The beta-PbO2 electrode was also superior to the dimensionally stable anode (Ti/Ru(0.3)Ti(0.7)O2) in visible light-induced photoactivity and PEC efficiency.

  15. Ni/Ti layered double hydroxide: synthesis, characterization and application as a photocatalyst for visible light degradation of aqueous methylene blue.

    PubMed

    Roy Chowdhury, Priyadarshi; Bhattacharyya, Krishna G

    2015-04-21

    Visible light responsive 2 : 1 Ni/Ti layered double hydroxide (LDH) was synthesized by a single step hydrothermal route using commercially available Ni(NO3)2·6H2O, TiCl4 and urea. The material exhibited significant absorption in the visible range with a very narrow band gap (2.68 eV). This could be attributed to structural defects as confirmed by diffuse reflectance spectroscopy (DRS), photoluminescence (PL), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. FT-IR, TGA, DTA, DSC, HR-TEM and SEM-EDX measurements yielded information about structural aspects, thermal stability and surface morphology. Surface and pore characteristics of the material were obtained from the BET isotherm for N2 adsorption at 77 K. Zeta potential measurements were used to characterize the electrical properties of the surface while XPS revealed changes in surface states and oxygen deficiencies. The material was found to be an excellent photocatalyst for the degradation of aqueous methylene blue in visible light. The photocatalytic properties of the material were explained on the basis of the narrow band gap, the high surface area and the presence of surface defects. The photocatalytic activity improved in alkaline media [pH 11.0, catalyst load 15 mg in 200 ml dye solution, dye concentration 1 × 10(-6) M (= 0.3198 mg L(-1))] due to the electrostatic attractions between the dye cations and the negative charges on the Ni/Ti LDH surface. The catalytic activity was found to be higher than the common commercial catalysts like ZnO, ZnS, NiO, TiO2 and Degussa P25. The catalytic activity was retained even after five methylene blue degradation cycles, demonstrating that the LDH could be an important addition to the field of wastewater treatment.

  16. Facile synthesis of novel CaFe2O4/g-C3N4 nanocomposites for degradation of methylene blue under visible-light irradiation.

    PubMed

    Vadivel, S; Maruthamani, D; Habibi-Yangjeh, A; Paul, Bappi; Dhar, Siddhartha Sankar; Selvam, Kaliyamoorthy

    2016-10-15

    Hybrid organic/inorganic nanocomposites comprised of calcium ferrite (CaFe2O4) and graphitic carbon nitride (g-C3N4) were prepared via a simple two-step process. The hybridized CaFe2O4/g-C3N4 heterostructure was characterized by a variety of techniques, including X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive analysis of X-rays (EDS), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy, electrochemical impedance spectroscopy (EIS), and photoelectrochemical studies. Photocatalytic activity of the prepared samples was evaluated against degradation of methylene blue (MB) under visible-light irradiation. The photocatalytic activity of CaFe2O4 30%/g-C3N4 nanocomposite, as optimum photocatalyst, for degradation of MB was superior to the pure CaFe2O4 and g-C3N4 samples. It was demonstrated that the photogenerated holes and superoxide ion radicals were the two main reactive species towards the photocatalytic degradation of MB over the nanocomposite. Based on the experimental results, a possible photocatalytic mechanism for the MB degradation over the nanocomposite was proposed. This work may provide some inspiration for the fabrication of spinel ferrites with efficient photocatalytic performance.

  17. Facile synthesis of zinc oxide nanoparticles decorated graphene oxide composite via simple solvothermal route and their photocatalytic activity on methylene blue degradation.

    PubMed

    Atchudan, Raji; Edison, Thomas Nesakumar Jebakumar Immanuel; Perumal, Suguna; Karthikeyan, Dhanapalan; Lee, Yong Rok

    2016-09-01

    Zinc oxide nanoparticles decorated graphene oxide (ZnO@GO) composite was synthesized by simple solvothermal method where zinc oxide (ZnO) nanoparticles and graphene oxide (GO) were synthesized via simple thermal oxidation and Hummers method, respectively. The obtained materials were thoroughly characterized by various physico-chemical techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Raman spectrum shows the intensity of D to G value was close to one which confirms the obtained GO and ZnO@GO composite possesses moderate graphitization. TEM images shows the ZnO nanoparticles mean size of 15±5nm were dispersed over the wrinkled graphene layers. The photocatalytic performance of ZnO@GO composite on degradation of methylene blue (MB) is investigated and the results show that the GO plays an important role in the enhancement of photocatalytic performance. The synthesized ZnO@GO composite achieves a maximum degradation efficiency of 98.5% in a neutral solution under UV-light irradiation for 15min as compared with pure ZnO (degradation efficiency is 49% after 60min of irradiation) due to the increased light absorption, the reduced charge recombination with the introduction of GO. Moreover, the resulting ZnO@GO composite possesses excellent degradation efficiency as compared to ZnO nanoparticles alone on MB.

  18. Featured Molecules: Ascorbic Acid and Methylene Blue

    NASA Astrophysics Data System (ADS)

    Coleman, William F.; Wildman, Randall J.

    2003-05-01

    The WebWare molecules of the month for May are featured in several articles in this issue. "Arsenic: Not So Evil After All?" discusses the pharmaceutical uses of methylene blue and its development as the first synthetic drug used against a specific disease. The JCE Classroom Activity "Out of the Blue" and the article "Greening the Blue Bottle" feature methylene blue and ascorbic acid as two key ingredients in the formulation of the blue bottle. You can also see a colorful example of these two molecules in action on the cover. "Sailing on the 'C': A Vitamin Titration with a Twist" describes an experiment to determine the vitamin C (ascorbic acid) content of citrus fruits and challenges students, as eighteenth-century sea captains, to decide the best fruit to take on a long voyage. Fully manipulable (Chime) versions of these and other molecules are available at Only@JCE Online.

  19. Hierarchical flower-like Co3-xFexO4 ferrite hollow spheres: facile synthesis and catalysis in the degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Hao, Jinhui; Yang, Wenshu; Zhang, Zhe; Pan, Shunhao; Lu, Baoping; Ke, Xi; Zhang, Bailin; Tang, Jilin

    2013-03-01

    A facile method is proposed for the synthesis of three-dimensional (3D) flower-like Co3-xFexO4 ferrite (CF) hollow spheres, using SiO2@FeOOH as precursor. The CF hollow spheres are efficient for the catalytic degradation of methylene blue (MB) in the presence of H2O2 at 80 °C. The obtained CF hollow spheres were characterized using transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, X-ray photo-electron spectroscopy, and N2 adsorption-desorption isotherm measurements. The formation of 3D hierarchical flower-like superstructure was influenced by the relative amount of urea used. As the mole ratio of CoCl2 and urea decreased, the structure of the products was tailored from yolk-like spheres to hollow spheres with different sized void interiors. Moreover, N2 adsorption-desorption isotherm analysis showed that the CF hollow spheres have a large specific surface area (163 m2 g-1) which provided more activity sites. The CF hollow spheres can catalyze the oxidation of MB efficiently. These results indicate that the designed CF hollow spheres exhibit promising capability for the degradation of dyes.A facile method is proposed for the synthesis of three-dimensional (3D) flower-like Co3-xFexO4 ferrite (CF) hollow spheres, using SiO2@FeOOH as precursor. The CF hollow spheres are efficient for the catalytic degradation of methylene blue (MB) in the presence of H2O2 at 80 °C. The obtained CF hollow spheres were characterized using transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, X-ray photo-electron spectroscopy, and N2 adsorption-desorption isotherm measurements. The formation of 3D hierarchical flower-like superstructure was influenced by the relative amount of urea used. As the mole ratio of CoCl2 and urea decreased, the structure of the products was tailored from yolk-like spheres to hollow spheres with different sized void interiors. Moreover, N2 adsorption-desorption isotherm

  20. Cu2O nanoparticles decorated BiVO4 as an effective visible-light-driven p-n heterojunction photocatalyst for methylene blue degradation

    NASA Astrophysics Data System (ADS)

    Min, Shixiong; Wang, Fang; Jin, Zhiliang; Xu, Jing

    2014-10-01

    Bismuth vanadate (BiVO4) is a chemically stable and nontoxic semiconductor (SC) photocatalyst that can absorb visible light to degrade most of pollutants in aqueous solution due to suitable band-gap energy (ca. 2.4 eV), but it usually shows a low activity in its pristine form owing to poor charge-separation characteristics and the weak surface adsorption properties. In this paper, we demonstrated that the photocatalytic activity of BiVO4 can be greatly enhanced by surface modification with Cu2O nanoparticles through polyol reduction method. The modified photocatalysts (Cu2O/BiVO4) with proper loading amount of Cu2O (0.75 wt%) showed the highest photocatalytic degradation activity for methylene blue (MB) degradation with the pseudo-first-order rate constant kapp and degradation efficiency two times higher than pristine BiVO4 under visible light and solar light irradiation. The characterizations of resulting photocatalysts revealed that decoration of Cu2O nanoparticles led to the formation of a p-n heterojunction at the contact interface of Cu2O and BiVO4, which narrowed the band gap of BiVO4 for extending the absorption range of visible light and promoted the charge transfer across interface for suppressing the recombination of photogenerated electron-hole pairs, thus improving the catalytic performance of photocatalysts. This work demonstrates that the structural integration of p-type Cu2O SC with n-type BiVO4 SC will be a new promising strategy to develop a high-efficient heterojunction photocatalyst for visible-light-driven degradation of pollutants.

  1. Methylene Blue Causing Serotonin Syndrome Following Cystocele Repair.

    PubMed

    Kapadia, Kailash; Cheung, Felix; Lee, Wai; Thalappillil, Richard; Florence, F Barry; Kim, Jason

    2016-11-01

    Methylene blue is an intravenously administered agent that may potentiate serotonin syndrome. The usage of methylene blue to evaluate ureters for injuries and patency during urological surgeries is recognized as common practice. However, there is no mention of serotonin syndrome caused by methylene blue in urological literature or for urological surgery. We report the first urological case in order to raise awareness of the risk for serotonin toxicity with utilizing methylene blue.

  2. The organotin coordination polymer [(n-Bu3Sn)4Fe(CN)6H2O] as effective catalyst towards the oxidative degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Etaiw, S. E. H.; Saleh, Dalia I.

    2014-01-01

    The structure of the supramolecular coordination polymer SCP 1; [(n-Bu3Sn)4Fe(CN)6H2O] consists of octahedral [Fe(CN)6]4- building blocks which are connected by the TBPY-5 configured n-Bu3Sn(CN..)2 fragments creating 3D-network structure. Fenton and photo-Fenton oxidative discoloration of Methylene Blue (MB) has been investigated by hydrogen peroxide catalyzed with the SCP 1. The reaction exhibited pseudo first-order kinetics with respect to each of MB and H2O2. The irradiation of the reaction with UV-light enhanced the rate of MB mineralization, Kobs = 0.76 h-1. Mineralization of MB was investigated by FT-IR spectra. Disodium salt of terephthalic acid photoluminescence probing technology was carried out to identify the reactive oxygen species. The different parameters that affect MB degradation rate were evaluated. Moreover, the efficiency of recycled the SCP 1 and the mechanism of degradation of MB dye were investigated.

  3. The organotin coordination polymer [(n-Bu3Sn)4Fe(CN)6H2O] as effective catalyst towards the oxidative degradation of methylene blue.

    PubMed

    Etaiw, S E H; Saleh, Dalia I

    2014-01-03

    The structure of the supramolecular coordination polymer SCP 1; [(n-Bu3Sn)4Fe(CN)6H2O] consists of octahedral [Fe(CN)6](4-) building blocks which are connected by the TBPY-5 configured n-Bu3Sn(CN..)2 fragments creating 3D-network structure. Fenton and photo-Fenton oxidative discoloration of Methylene Blue (MB) has been investigated by hydrogen peroxide catalyzed with the SCP 1. The reaction exhibited pseudo first-order kinetics with respect to each of MB and H2O2. The irradiation of the reaction with UV-light enhanced the rate of MB mineralization, Kobs=0.76 h(-1). Mineralization of MB was investigated by FT-IR spectra. Disodium salt of terephthalic acid photoluminescence probing technology was carried out to identify the reactive oxygen species. The different parameters that affect MB degradation rate were evaluated. Moreover, the efficiency of recycled the SCP 1 and the mechanism of degradation of MB dye were investigated.

  4. Metallogel template fabrication of pH-responsive copolymer nanowires loaded with silver nanoparticles and their photocatalytic degradation of methylene blue.

    PubMed

    Wen, Xing; Tang, Liming; Li, Botian

    2014-10-01

    Poly(N,N'-methylenebisacrylamide-4-vinylpyridine) (P(MBA-4VP)) nanowires loaded with silver nanoparticles (Ag NPs) have been fabricated by silver metallogel template copolymerization, and subsequently, silver ions are reduced instead of the template being removed. Ag NPs with a diameter of 5-15 nm were dispersed throughout the core of P(MBA-4VP) nanowires. The size and distribution of the formed Ag NPs could be finely controlled by reduction time. The pH sensitivity of P(MBA-4VP) nanowires offers the possibility of Ag NP release from the nanowires under acidic conditions. The photocatalytic performance of the P(MBA-4VP) nanowires loaded with Ag NPs was evaluated for the degradation of methylene blue (MB) under UV light irradiation. Their rate of degradation is dependent on the content and size of the Ag NPs, as well as the pH values of the MB solution. Moreover, the P(MBA-4VP) nanowires loaded with Ag NPs exhibited high photostability, and the photocatalytic efficiency reduced by only 1.81% after being used three times.

  5. Hierarchical flower-like Co₃-xFexO₄ ferrite hollow spheres: facile synthesis and catalysis in the degradation of methylene blue.

    PubMed

    Hao, Jinhui; Yang, Wenshu; Zhang, Zhe; Pan, Shunhao; Lu, Baoping; Ke, Xi; Zhang, Bailin; Tang, Jilin

    2013-04-07

    A facile method is proposed for the synthesis of three-dimensional (3D) flower-like Co3-xFexO4 ferrite (CF) hollow spheres, using SiO2@FeOOH as precursor. The CF hollow spheres are efficient for the catalytic degradation of methylene blue (MB) in the presence of H2O2 at 80 °C. The obtained CF hollow spheres were characterized using transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, X-ray photo-electron spectroscopy, and N2 adsorption-desorption isotherm measurements. The formation of 3D hierarchical flower-like superstructure was influenced by the relative amount of urea used. As the mole ratio of CoCl2 and urea decreased, the structure of the products was tailored from yolk-like spheres to hollow spheres with different sized void interiors. Moreover, N2 adsorption-desorption isotherm analysis showed that the CF hollow spheres have a large specific surface area (163 m(2) g(-1)) which provided more activity sites. The CF hollow spheres can catalyze the oxidation of MB efficiently. These results indicate that the designed CF hollow spheres exhibit promising capability for the degradation of dyes.

  6. Visible light induced degradation of methylene blue using CeO2/V2O5 and CeO2/CuO catalysts.

    PubMed

    Saravanan, R; Joicy, S; Gupta, V K; Narayanan, V; Stephen, A

    2013-12-01

    In the present study, the nanocatalysts CeO2, V2O5, CuO, CeO2/V2O5 and CeO2/CuO were synthesized by thermal decomposition method. This method is simple, fast and cost effective compared with other preparation methods. The synthesized catalysts were characterized by different techniques. The XRD and XPS results confirmed the structure and the oxidization states of the nanocomposite materials. DRS results suggested that the prepared CeO2/V2O5 and CeO2/CuO nanocomposites can generate more electrons and holes under visible light irradiation. The photocatalytic activities of prepared catalysts were evaluated using the degradation of aqueous methylene blue solution as a model compound under visible light irradiation. In addition, the nanocomposite (CeO2/V2O5 and CeO2/CuO) materials were employed to degrade the textile effluent under visible light condition.

  7. Ultra-sustainable Fe78Si9B13 metallic glass as a catalyst for activation of persulfate on methylene blue degradation under UV-Vis light

    NASA Astrophysics Data System (ADS)

    Jia, Zhe; Duan, Xiaoguang; Zhang, Wenchang; Wang, Weimin; Sun, Hongqi; Wang, Shaobin; Zhang, Lai-Chang

    2016-12-01

    Stability and reusability are important characteristics of advanced catalysts for wastewater treatment. In this work, for the first time, sulfate radicals (SO4•‑) with a high oxidative potential (Eo = 2.5–3.1 V) were successfully activated from persulfate by a Fe78Si9B13 metallic glass. This alloy exhibited a superior surface stability and reusability while activating persulfate as indicated by it being used for 30 times while maintaining an acceptable methylene blue (MB) degradation rate. The produced SiO2 layer on the ribbon surface expanded strongly from the fresh use to the 20th use, providing stable protection of the buried Fe. MB degradation and kinetic study revealed 100% of the dye degradation with a kinetic rate k = 0.640 within 20 min under rational parameter control. The dominant reactive species for dye molecule decomposition in the first 10 min of the reaction was hydroxyl radicals (•OH, Eo = 2.7 V) and in the last 10 min was sulfate radicals (SO4•‑), respectively. Empirical operating variables for dye degradation in this work were under catalyst dosage 0.5 g/L, light irradiation 7.7 μW/cm2, and persulfate concentration 1.0 mmol/L. The amorphous Fe78Si9B13 alloy in this work will open a new gate for wastewater remediation.

  8. Enhanced photocatalytic degradation and adsorption of methylene blue via TiO2 nanocrystals supported on graphene-like bamboo charcoal

    NASA Astrophysics Data System (ADS)

    Wu, Fangjun; Liu, Wei; Qiu, Jielong; Li, Jinzhen; Zhou, Wuyi; Fang, Yueping; Zhang, Shuting; Li, Xin

    2015-12-01

    In this study, a novel efficient photocatalytic nanomaterial, TiO2 nanocrystals supported on graphene-like bamboo charcoal, has been successfully synthesized via a facile multi-step process. The structural and optical properties of the as-prepared samples were characterized by different techniques, such as X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis absorption spectroscopy, photoluminescence spectra (PL), Raman spectra and nitrogen adsorption-desorption isotherms. The photocatalytic activities under sunlight were evaluated by the degradation of methylene blue (MB). The results indicated that the ternary hybrid photocatalysts exhibited much higher photocatalytic activities toward the degradation of MB than the pure TiO2 under UV light irradiation. Moreover, the optimum weight content of graphene-like bamboo charcoal in composite photocatalysts was 6 wt% for achieving the maximum photocatalytic degradation rate. The apparent rate constant of the best sample (0.0509 min-1) was about 3 times greater than that of the commercial P25 (0.0170 min-1). The adsorption and degradation kinetics of MB can be described by the pseudo-first-order model and apparent first-order kinetics model, respectively. The highly enhanced photocatalytic performance was attributed to the synergetic effect of graphene-like carbon and bamboo charcoal, which lead to the promoted charge separation and reduction reaction of oxygen, and enhanced adsorption capacities of MB, respectively. The composite photocatalysts displayed a high photochemical stability under repeated irradiation. This work may provide new insights and understanding on the graphene-like bamboo charcoal as an excellent support for photocatalyst nanoparticles to enhance their visible-light photocatalytic activity.

  9. Ultra-sustainable Fe78Si9B13 metallic glass as a catalyst for activation of persulfate on methylene blue degradation under UV-Vis light

    PubMed Central

    Jia, Zhe; Duan, Xiaoguang; Zhang, Wenchang; Wang, Weimin; Sun, Hongqi; Wang, Shaobin; Zhang, Lai-Chang

    2016-01-01

    Stability and reusability are important characteristics of advanced catalysts for wastewater treatment. In this work, for the first time, sulfate radicals (SO4∙−) with a high oxidative potential (Eo = 2.5–3.1 V) were successfully activated from persulfate by a Fe78Si9B13 metallic glass. This alloy exhibited a superior surface stability and reusability while activating persulfate as indicated by it being used for 30 times while maintaining an acceptable methylene blue (MB) degradation rate. The produced SiO2 layer on the ribbon surface expanded strongly from the fresh use to the 20th use, providing stable protection of the buried Fe. MB degradation and kinetic study revealed 100% of the dye degradation with a kinetic rate k = 0.640 within 20 min under rational parameter control. The dominant reactive species for dye molecule decomposition in the first 10 min of the reaction was hydroxyl radicals (∙OH, Eo = 2.7 V) and in the last 10 min was sulfate radicals (SO4∙−), respectively. Empirical operating variables for dye degradation in this work were under catalyst dosage 0.5 g/L, light irradiation 7.7 μW/cm2, and persulfate concentration 1.0 mmol/L. The amorphous Fe78Si9B13 alloy in this work will open a new gate for wastewater remediation. PMID:27922099

  10. Ultra-sustainable Fe78Si9B13 metallic glass as a catalyst for activation of persulfate on methylene blue degradation under UV-Vis light.

    PubMed

    Jia, Zhe; Duan, Xiaoguang; Zhang, Wenchang; Wang, Weimin; Sun, Hongqi; Wang, Shaobin; Zhang, Lai-Chang

    2016-12-06

    Stability and reusability are important characteristics of advanced catalysts for wastewater treatment. In this work, for the first time, sulfate radicals (SO4∙(-)) with a high oxidative potential (E(o) = 2.5-3.1 V) were successfully activated from persulfate by a Fe78Si9B13 metallic glass. This alloy exhibited a superior surface stability and reusability while activating persulfate as indicated by it being used for 30 times while maintaining an acceptable methylene blue (MB) degradation rate. The produced SiO2 layer on the ribbon surface expanded strongly from the fresh use to the 20(th) use, providing stable protection of the buried Fe. MB degradation and kinetic study revealed 100% of the dye degradation with a kinetic rate k = 0.640 within 20 min under rational parameter control. The dominant reactive species for dye molecule decomposition in the first 10 min of the reaction was hydroxyl radicals (∙OH, E(o) = 2.7 V) and in the last 10 min was sulfate radicals (SO4∙(-)), respectively. Empirical operating variables for dye degradation in this work were under catalyst dosage 0.5 g/L, light irradiation 7.7 μW/cm(2), and persulfate concentration 1.0 mmol/L. The amorphous Fe78Si9B13 alloy in this work will open a new gate for wastewater remediation.

  11. Preparation of h-MoO3 and α-MoO3 nanocrystals: comparative study on photocatalytic degradation of methylene blue under visible light irradiation.

    PubMed

    Chithambararaj, A; Sanjini, N S; Velmathi, S; Bose, A Chandra

    2013-09-21

    A detailed study on visible light photocatalytic degradation of methylene blue (MB) has been investigated in aqueous heterogeneous media containing hexagonal phase molybdenum oxide (h-MoO3) nanocrystals (NCs) which was identified as a new material for visible light driven photocatalysis. A simple and template-free solution based chemical precipitation method was employed to synthesize h-MoO3 NCs by reacting ammonium heptamolybdate tetrahydrate (AHM) with nitric acid. The formation and growth mechanism of h-MoO3 microstructures was explained. In addition, by annealing the h-MoO3 sample, the phase stability of hexagonal was retained up to 410 °C and showed an irreversible phase transition from hexagonal (h-MoO3) to highly stable orthorhombic phase (α-MoO3). Finally, the photocatalytic activities of h-MoO3 and α-MoO3 samples were evaluated using the degradation of MB, representing an organic pollutant of dye wastewater. The effects of various experimental parameters such as catalyst loading, initial dye concentration, light intensity, and operating temperature were analyzed for the degradation of MB. The results demonstrated that the efficiency of visible light assisted MB degradation using h-MoO3 NCs can be effectively enhanced by catalyst loading, light intensity, and operating temperature. However, the efficiency declined with the increase in initial dye concentration. Optimum conditions for higher photocatalytic performance were recognized as a catalyst loading of 100 mg L(-1), a dye concentration of 12 mg L(-1), a light intensity of 350 mW cm(-2), and an operating temperature of 45 °C.

  12. Methylene blue promotes quiescence of rat neural progenitor cells.

    PubMed

    Xie, Luokun; Choudhury, Gourav R; Wang, Jixian; Park, Yong; Liu, Ran; Yuan, Fang; Zhang, Chun-Li; Yorio, Thomas; Jin, Kunlin; Yang, Shao-Hua

    2014-01-01

    Neural stem cell-based treatment holds a new therapeutic opportunity for neurodegenerative disorders. Here, we investigated the effect of methylene blue on proliferation and differentiation of rat neural progenitor cells (NPCs) both in vitro and in vivo. We found that methylene blue inhibited proliferation and promoted quiescence of NPCs in vitro without affecting committed neuronal differentiation. Consistently, intracerebroventricular infusion of methylene blue significantly inhibited NPC proliferation at the subventricular zone (SVZ). Methylene blue inhibited mTOR signaling along with down-regulation of cyclins in NPCs in vitro and in vivo. In summary, our study indicates that methylene blue may delay NPC senescence through enhancing NPCs quiescence.

  13. Adsorptive separation and photocatalytic degradation of methylene blue dye on titanate nanotube powders prepared by hydrothermal process using metal Ti particles as a precursor.

    PubMed

    Hu, Keshui; Xiao, Xin; Cao, Xiufang; Hao, Rong; Zuo, Xiaoxi; Zhang, Xiaojing; Nan, Junmin

    2011-08-30

    Titanate nanotube powders (TNTPs) with the twofold removal ability, i.e. adsorptive separation and photocatalytic degradation, are synthesized under hydrothermal conditions using metal Ti particles as a precursor in the concentrated alkaline solution, and their morphology, structure, adsorptive and photocatalytic properties are investigated. Under hydrothermal conditions, the titanate nanotubes (TNTs) with pore diameter of 3-4nm are produced on the surface of metal Ti particles, and stacked together to form three-dimensional (3D) network with porous structure. The TNTPs synthesized in the autoclave at 130°C for 24h exhibits a maximum adsorption capability of about 197mg g(-1) in the neutral methylene blue (MB) solution (40mg L(-1)) within 90min, the adsorption process can be described by pseudo second-order kinetics model. Especially, in comparison with the adsorptive and the photocatalytic processes are performed in turn, about 50min can be saved through synchronously utilizing the double removal ability of TNTPs when the removal ratio of MB approaches 95% in MB solution (40mg L(-1)) at a solid-liquid (S/L) ratio of 1:8 under ultraviolet (UV) light irradiation. These 3D TNTPs with the twofold removal properties and easier separation ability for recycling use show promising prospect for the treatment of dye pollutants from wastewaters in future industrial application.

  14. Utilization of visible to NIR light energy by Yb+3, Er+3 and Tm+3 doped BiVO4 for the photocatalytic degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Regmi, Chhabilal; Kshetri, Yuwaraj K.; Ray, Schindra Kumar; Pandey, Ramesh Prasad; Lee, Soo Wohn

    2017-01-01

    Lanthanide-doped BiVO4 semiconductors with efficient photocatalytic activities over a broad range of the solar light spectrum have been synthesized by the microwave hydrothermal method using ethylenediaminetetraacetic acid (EDTA). The structural, morphological, and optical properties of the as-synthesized samples were evaluated by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray powder diffraction (XRD), Raman spectroscopy, FT-IR spectroscopy, UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The chemical compositions were analyzed by X-ray photoelectron spectroscopy (XPS). The toxicity of the samples was measured using Mus musculus skin melanoma cells (B16-F10 (ATCC CRL-6475™)) and were found to be nontoxic for human cells. The photocatalytic efficiency of the prepared samples was evaluated by methylene blue (MB) degradation. The best photocatalytic activity was shown by BiVO4 with 6:3:3 mol percentage of Yb+3:Er+3:Tm+3 in all solar light spectrum. The synthesized samples possess low band gap energy and a hollow structure suitable for the better photocatalytic activity. The observed NIR photoactivity supports that the upconversion mechanism is involved in the overall photocatalytic process. Therefore, this approach provides a better alternative upconversion material for integral solar light absorption.

  15. Caulerpa racemosa: a marine green alga for eco-friendly synthesis of silver nanoparticles and its catalytic degradation of methylene blue.

    PubMed

    Edison, Thomas Nesakumar Jebakumar Immanuel; Atchudan, Raji; Kamal, Chennappan; Lee, Yong Rok

    2016-09-01

    In this study, a simple and green method has been demonstrated for the synthesis of highly stable silver nanoparticles (AgNPs) using aqueous extract of Caulerpa racemosa (C. racemosa) as a reducing and capping agent. The formation and stability of AgNPs were studied using visual observation and UV-Visible (UV-Vis) spectroscopy. The stable AgNPs were further characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and high resolution transmission electron microscopy (HR-TEM) with energy dispersive spectroscopic (EDS) methods. The biosynthesized AgNPs showed a sharp surface plasmon resonance peak at 441 nm in the visible region and they have extended stability which has been confirmed by the UV-Vis spectroscopic results. XRD result revealed the crystalline nature of synthesized AgNPs and they are mainly oriented in (111) plane. FT-IR studies proved that the phytoconstituents of C. racemosa protect the AgNPs from aggregation and also which are responsible for the high stability. The size of synthesized AgNPs was approximately 25 nm with distorted spherical shape, identified from the HR-TEM images. The synthesized AgNPs showed excellent catalytic activity towards degradation of methylene blue.

  16. Porous FeOx/BiVO4-deltaS0.08: highly efficient photocatalysts for the degradation of methylene blue under visible-light illumination.

    PubMed

    Zhao, Zhenxuan; Dai, Hongxing; Deng, Jiguang; Liu, Yuxi; Wang, Yuan; Li, Xinwei; Bai, Guangmei; Gao, Baozu; Au, Chak Tong

    2013-10-01

    Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide (y wt.% FeOx/BiVO4-deltaS0.08, y = 0.06, 0.76, and 1.40) photocatalysts were fabricated using the dodecylamine-assisted alcohol-hydrothermal and incipient wetness impregnation methods, respectively. It is shown that the y wt.% FeOx/BiVO4-deltaS0.08 photocatalysts contained a monoclinic scheetlite BiVO4 phase with a porous olive-like morphology, a surface area of 8.8-9.2 m2/g, and a bandgap energy of 2.38-2.42 eV. There was co-presence of surface Bi5+, Bi3+, V5+, V3+, Fe3+, and Fe2+ species in y wt.% FeOx/BiVO4-deltaS0.08. The 1.40 wt.% FeOx/BiVO4-deltaS0.08 sample performed the best for Methylene Blue degradation under visible-light illumination. The photocatalytic mechanism was also discussed. We believe that the sulfur and FeOx co-doping, higher oxygen adspecies concentration, and lower bandgap energy were responsible for the excellent visible-light-driven catalytic activity of 1.40 wt.% FeOx/BiVO4-deltaS0.08.

  17. Effect of Sn ratio on the photocatalytic degradation of methylene blue and soot of ink by TiO 2-SnO 2 nanostructured thin films

    NASA Astrophysics Data System (ADS)

    El-Maghraby, E. M.

    2010-05-01

    The photocatalytic performance of rutile-, anatase- and mixed-phases of nanocomposite TiO 2-SnO 2 thin films, with different Sn ratios was tested. The absorption spectra of the prepared films show enhancement of high absorbance in the visible region for samples with Ti to Sn ratios of 3:1. Degradation of both methylene blue (MB) and soot of ink (SI) was examined by transmittance change under UV-vis irradiation. Sn doping improved the photocatalytic activity of the films. The results reveal that the smoother the sample surface and smaller the particle size; the highest the photocatalytic activity. Moreover, thin films doped with Ti to Sn ratios of 50:1 and 3:1 photocatalyst could more readily photodegrade MB and SI under visible-light irradiation. The high visible-light catalytic activity of the prepared photocatalyst resulted from the high absorbance in the visible-light range and also the reduced electron-hole recombination rate.

  18. Facile synthesis of bird's nest-like TiO2 microstructure with exposed (001) facets for photocatalytic degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Zhang, Guozhong; Zhang, Shuqu; Wang, Longlu; Liu, Ran; Zeng, Yunxiong; Xia, Xinnian; Liu, Yutang; Luo, Shenglian

    2017-01-01

    The scrupulous design of hierarchical structure and highly active crystal facets exposure is essential for the creation of photocatalytic system. However, it is still a big challenge for scrupulous design of TiO2 architectures. In this paper, bird's nest-like anatase TiO2 microstructure with exposed highly active (001) surface has been successfully synthesized by a facile one-step solvothermal method. Methylene blue (MB) is chosen as a model pollutant to evaluate photocatalytic activity of as-obtained TiO2 samples. The results show that the photocatalytic activity of the bird's nest-like sample is more excellent than P25 in the degradation of MB due to high specific surface area and highly active (001) crystal facets exposure when tested under simulated solar light. Besides, it can be readily separated from the photocatalytic system by sedimentation after photocatalytic reaction, which is a significant advantage against conventional powder photocatalyst. The bird's nest-like microspheres with novel structure may have potential application in photocatalysis and other fields.

  19. Titania species on two-dimensional HNbMoO6 nanosheets: structural feature, interaction model, and synergistic effect for photocatalytic degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Hu, Lifang; He, Jie; Xu, Lei; Li, Dewei; Zhang, Peipei

    2016-10-01

    HNbMoO6-based nanocomposite material T-HNbMoO6 is assembled by titania species dispersed on HNbMoO6 nanosheets (N-HNbMoO6), which is obtained through the mechanical exfoliation of layered HNbMoO6 (L-HNbMoO6). The microstructures, skeleton features, and spectral-response characteristics of the as-prepared materials were characterized by means of technologies, such as powder x-ray diffraction, field emission scanning electron microscope with energy dispersive spectroscopy mapping, high-resolution transmission electron microscopy with energy dispersive x-ray spectrometer, N2 adsorption-desorption isotherms, laser Raman spectroscopy, x-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, Mott-Schottky curves, and H2 temperature-programmed reduction analysis. The photocatalytic activity was evaluated by the degradation of methylene blue dye under the Xe lamp irradiation. The results showed that the titania species are dispersed on the surface of N-HNbMoO6 resulting from the interaction between guest titania species and host N-HNbMoO6. T-HNbMoO6 owns the best photocatalytic performance, which may be attributed to the synergistic effect between N-HNbMoO6 and titania species.

  20. Study of the degradation of methylene blue by semi-solid-state fermentation of agricultural residues with Phanerochaete chrysosporium and reutilization of fermented residues.

    PubMed

    Zeng, Guangming; Cheng, Min; Huang, Danlian; Lai, Cui; Xu, Piao; Wei, Zhen; Li, Ningjie; Zhang, Chen; He, Xiaoxiao; He, Yan

    2015-04-01

    The degradation of methylene blue (MB) by semi-solid-state fermentation of agricultural residues rice straw with Phanerochaete chrysosporium and the reutilization of fermented residues was investigated. A maximum decolorization of 84.8% for an initial dye concentration of 0.4 g/L was observed at the optimal operating conditions (temperature 35 °C, pH 5). As compared to the previous results obtained using synthetic materials as substrate, the results in the present study revealed an excellent performance of the bioreactor in decolorizing the wastewater containing MB, which is due to this type of cultivation reproducing the natural living conditions of the white rot fungi. Among the two ligninolytic enzymes that are responsible to the decolorization, manganese peroxidase (MnP) activity was found better correlated with decoloration percentage. Our results also provide a first step to recycling the fermented residues for the removal of MB from aqueous solutions, the maximum adsorption capacity of the fermented residues reached 51.4 mg/g.

  1. A facile one-pot hydrothermal synthesis of β-MnO{sub 2} nanopincers and their catalytic degradation of methylene blue

    SciTech Connect

    Cheng, Gao; Yu, Lin Lin, Ting; Yang, Runnong; Sun, Ming; Lan, Bang; Yang, Lili; Deng, Fangze

    2014-09-15

    Branched β-MnO{sub 2} bipods with novel nanopincer morphology were prepared by a facile one-pot hydrothermal method via a redox reaction between NaClO{sub 3} and MnSO{sub 4} in sulfuric acid solution without using any surfactants or templates. The products were characterized in detail by various techniques including X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, surface area analyzer, field emission scanning electron microscopy and transmission electron microscopy. Results show that the obtained β-MnO{sub 2} nanopincers consist of two sharp nanorods with a diameter of 100–200 nm and a length of 1–2 μm. The concentration of H{sub 2}SO{sub 4} solution plays an important role in controlling the crystal phase and morphology of the final product. A possible formation mechanism for the β-MnO{sub 2} nanopincers was proposed. Moreover, these β-MnO{sub 2} nanostructures exhibited better catalytic performance than the commercial MnO{sub 2} particles to decompose methyl blue (MB) in the presence of H{sub 2}O{sub 2}. - Graphical abstract: Branched β-MnO{sub 2} bipods with novel nanopincer morphology were prepared by a facile one-pot hydrothermal method through oxidizing MnSO{sub 4} with NaClO{sub 3} in H2SO{sub 4} condition without using any surfactants or templates. - Highlights: {sup •} Branched β-MnO{sub 2} nanopincers were prepared by a facile one-pot hydrothermal method. {sup •} Morphology and crystal phase of MnO{sub 2} were controlled by the H{sub 2}SO{sub 4} concentration. {sup •} A possible formation mechanism for the obtained β-MnO{sub 2} nanopincers was proposed. {sup •} The products showed great catalytic performance in degradation of methylene blue.

  2. Metachromasy as an indicator of photostabilization of methylene blue adsorbed to clays and minerals.

    PubMed

    Samuels, Maya; Mor, Omer; Rytwo, Giora

    2013-04-05

    The influence of methylene blue adsorption to different clays on its photodegradation was studied. Methylene blue in solution was decomposed by sunlight in a zero-order process. Adsorption to some clay minerals (sepiolite and vermiculite) and a zeolite (clinoptilolite) accelerated the degradation process, and converted it to a first-order reaction. On the other hand, adsorption to other clay minerals (palygorskite and montmorillonite) stabilized the dye and prevented its degradation. Interestingly, in the clay-dye complexes that exhibited stability, clear metachromasy of the adsorbed methylene blue occurred, whereas the effect was not observed in the clay-dye complexes that underwent photodegradation.

  3. Visible light-driven photocatalytic degradation of the organic pollutant methylene blue with hybrid palladium-fluorine-doped titanium oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Lázaro-Navas, Sonia; Prashar, Sanjiv; Fajardo, Mariano; Gómez-Ruiz, Santiago

    2015-02-01

    The synthesis of mesoporous aggregates of titanium oxide nanoparticles (F0) is described using a very cheap and simple synthetic protocol. This consists of the reaction of titanium tetraisopropoxide and a solution of HNO3 in water (pH 2.0) and subsequent filtration. In addition, fluorine-doped titanium oxides (F1, F2, F5 and F10) were synthesized using the same method, adding increasing amounts of NaF to the reaction mixture (avoiding the use of expensive reagents such as NH4F or trifluoroacetic acid). The resulting materials were calcined at different temperatures (500, 600 and 650 °C) giving particles sized between 10 and 20 nm. Furthermore, a hybrid F-doped TiO2 with supported palladium nanoparticles of ca. 20 nm (F5-500-Pd1) was synthesized by grafting an organometallic palladium(II) salt namely [Pd(cod)Cl2] (cod = 1,5-cyclooctadiene). Photocatalytic studies of the degradation of methylene blue (MB) were carried out under UV light using all the synthesized material (non-doped an F-doped TiO2), observing that the increase in the quantity of fluorine has a positive effect on the photocatalytic activity. F5-500 is apparently the material which has the most convenient structural properties (in terms of surface area and anatase/rutile ratio) and thus a higher photocatalytic activity. The hybrid material F-doped TiO2-Pd nanoparticles (F5-500-Pd1) has a lower band gap value than F5-500, and thus photocatalytic degradation of MB under LED visible light was achieved using F5-500-Pd1 as photocatalyst.

  4. Preparation of PEDOT/GO, PEDOT/MnO2, and PEDOT/GO/MnO2 nanocomposites and their application in catalytic degradation of methylene blue.

    PubMed

    Zhang, Li; Jamal, Ruxangul; Zhao, Qin; Wang, Minchao; Abdiryim, Tursun

    2015-01-01

    The nanocomposite materials of poly(3,4-ethylenedioxythiophene)/graphene oxide (PEDOT/GO), poly(3,4-ethylenedioxythiophene)/MnO2 (PEDOT/MnO2), and poly(3, 4-ethylenedioxythiophene)/graphene oxide/MnO2 (PEDOT/GO/MnO2) were successfully prepared by facile and template-free solution method. The structure and morphology of nanonanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible absorption spectra (UV-vis), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX), respectively. The catalytic activities of nanocomposites were investigated through the degradation processes of methylene blue (MB) solution under dark, UV light, and nature sunlight irradiation, respectively. The results displayed that nanocomposites were successfully synthesized, and PEDOT/GO had higher conjugation length and doped degree than pure PEDOT. However, the introduction of MnO2 could lead to the reduction of conjugation length and doped degree in PEDOT/MnO2 and PEDOT/GO/MnO2 nanocomposites. The field emission scanning electron microscope (FESEM) analysis also showed that both MnO2 and GO had some effect on the morphology of nanocomposites. The catalytic activities of pure PEDOT and nanocomposites were in the order of PEDOT/GO/MnO2 > PEDOT/MnO2 > PEDOT/GO > pure PEDOT. Besides, the catalytic results also showed that the highest degradation efficiency of MB after 7 h occurred in the PEDOT/GO/MnO2 composite in three irradiation.

  5. Synthesis and properties of (Yb, N)-TiO{sub 2} photocatalyst for degradation of methylene blue (MB) under visible light irradiation

    SciTech Connect

    Zhang, J.; Xu, L.J.; Zhu, Z.Q.; Liu, Q.J.

    2015-10-15

    Highlights: • The (Yb, N)-TiO{sub 2} nanoparticles were prepared and characterized. • The spectrum absorption region of (Yb, N)-TiO{sub 2} is red-shifted to visible light. • The recombination of the photo-generated electron–hole pairs of (Yb, N)-TiO{sub 2} is suppressed. • The photocatalytic activity of (Yb, N)-TiO{sub 2} is more higher than that of TiO{sub 2}-P25, N-TiO{sub 2} and the Yb-TiO{sub 2}. - Abstract: (Yb, N)-TiO{sub 2} photocatalyst has been synthesized by sol–gel method combined with microwave chemical synthesis. Also, the efficiency of the (Yb, N)-TiO{sub 2} as a photocatalyst for the degradation of methylene blue (MB) using visible light irradiation has been evaluated. The prepared samples were characterized by XRD, TEM, XPS, UV–vis-DRS and PL. The results show that the (Yb, N)-TiO{sub 2} photocatalyst has the anatase TiO{sub 2} crystalline phase. The TEM micrograph demonstrated that the average particle size of the sample was about 12 nm. The band-gap energy absorption edge shifted to longer wavelength as compared to commercial TiO{sub 2}-P25, N-TiO{sub 2} and the Yb-TiO{sub 2} prepared by our group. Results of degradation revealed that the (Yb, N)-TiO{sub 2} has shown much more higher photocatalytic activity than that of the TiO{sub 2}-P25, the N-TiO{sub 2} and the Yb-TiO{sub 2} under the visible light.

  6. Matrix-assisted laser desorption ionization time-of-flight mass spectrometric analysis of degradation products after treatment of methylene blue aqueous solution with three-dimensionally integrated microsolution plasma

    NASA Astrophysics Data System (ADS)

    Shirafuji, Tatsuru; Nomura, Ayano; Hayashi, Yui; Tanaka, Kenji; Goto, Motonobu

    2016-01-01

    Methylene blue can be degraded in three-dimensionally integrated microsolution plasma. The degradation products have been analyzed by matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry to understand the degradation mechanisms. The results of MALDI TOF mass spectrometry have shown that sulfoxide is formed at the first stage of the oxidation. Then, partial oxidation proceeds on the methyl groups left on the sulfoxide. The sulfoxide is subsequently separated to two benzene derivatives. Finally, weak functional groups are removed from the benzene derivatives.

  7. Oxidative decolorization of methylene blue using pelagite.

    PubMed

    Zhu, Mao-Xu; Wang, Zheng; Zhou, Liang-Yong

    2008-01-15

    Pelagite generally has large surface area and high adsorbing and oxidizing reactivity due to highly amorphous nature, and high reducing potential of Mn (hydro)oxide phases present in it. In the present study, pelagite, collected from the East Pacific Ocean, was tested as a potential oxidant for decolorization of methylene blue (MB) in a batch system under air-bubbling and motor-stirring conditions. The effects of suspension pH (3.0-10.0), MB concentration (10-100 mgL(-1)) and loading (0.2-3.0 gL(-1)), and particle size (100-200 mesh) of pelagite on kinetics of MB decolorization were assessed. Results show that in typical concentration range of dye wastewaters (10-50 mgL(-1)), pelagite can be used as a highly efficient material for oxidative degradation of MB. MB decolorization was through a surface mechanism, that is, formation of surface precursor complex between MB and surface bound Mn(III, IV) center, followed by electron transfer within the surface complex. Iron (hydro)oxide phases present in the pelagite did not play an important role in MB decolorization. Suspension pH exerted double-edged effects on MB decolorization by influencing the formation of surface precursor complex, and reducing potential of the system. Kinetic rate of MB decolorization is directly proportional to saturation degree of available reaction sites by MB adsorption. At the initial and later stages, the kinetics for MB decolorization with respect to MB concentration, pelagite loading, and particle size could be described separately using two pseudofirst rate equations, except at very high pelagite loading (3.0 mgL(-1)). Accumulation of Mn(2+) and probably some organic intermediates exerted marked inhibitory effect on MB decolorization. Vigorous dynamic condition was favorable for MB decolorization. The presence of oxygen could enhance MB decolorization to a limited extent.

  8. An introduction to photocatalysis through methylene blue photodegradation

    NASA Astrophysics Data System (ADS)

    Petit, Matthieu; Michez, Lisa; Raimundo, Jean-Manuel; Malinowski, Tuhiti; Dumas, Philippe

    2016-11-01

    We described a simple experimental set-up for lab work on the photocatalytic degradation of methylene blue by TiO2 nanoparticles. The photocatalysis process can be used for many applications. Treatments for diluted wastewater industries, air purifying in underground car parks, and preventing fouling on glass surfaces, are some of the potential applications of this phenomenon. The described experiment is easy to perform and the interpretation can be easily adapted to different levels of students, from high school students demonstrating their interest in sustainable development, to students obtaining a Masters in science departments who want to propose a full explanation for all phenomena of the photocatalytic process. Starting with a description of the experimental set-up, we analysed the photocatalyst nanoparticles and applied the Langmuir-Hinshelwood model to our experimental data. Finally we briefly discussed the respective energetic levels of the photocatalyst semiconductor and methylene blue.

  9. [Research of the photoelectrocatalysis degradation of methylene blue of TiO2 nanotube array films annealed in oxygen atmospheres].

    PubMed

    Zhang, Xi; Liao, Lei; Ling, Yun-Han; Qin, Ai-Miao; Zhao, Cheng-Gen; Zhao, Fei-Chao

    2011-11-01

    Well-aligned and uniform titanium dioxide nanotube arrays were fabricated in situ on titanium substrate by electrochemical anodic oxidation. SEM images indicate that the TiO2 nanotubes are well organized into high-density uniform arrays,with diameter ranging in size from 70 to 100 nm. The XRD patterns show that the sample fabricated by anodic oxidation is amorphous without being annealed. As the 500 degrees C annealed sample crystallized in the anatase phase, which is in good photocatalytic activity. In quartz glass reactor, the photoelectrocatalytic degradation of MB in aqueous solutions as well as the effect factors and then to 0.1 mol/L NaCl as the electrolyte, under with in oxygen atmospheres annealed the applied bias is 0.5 V and has a pH = 3.25, light intensity is 1 000 microW/cm2 and the surface area of nano-tube array film conditions, will help to improve the TiO2 nanotubes array film photoelectrocatalysis degradation of MB degradation efficiency is 99.56%. The results of EIS analyses revealed that the surface reaction step was the only rate limiting step either for the photoelectrocatalytic process. The extra bias potential could decrease the values of the electron-transfer resistance and increase the separation efficiency of photogenerated electron-hole pairs.

  10. A facile solvothermal approach of novel Bi2S3/TiO2/RGO composites with excellent visible light degradation activity for methylene blue

    NASA Astrophysics Data System (ADS)

    Liu, Ya; Shi, Yidan; Liu, Xiang; Li, Hexing

    2017-02-01

    In this paper, novel photocatalyst Bi2S3/TiO2/RGO composites were successfully fabricated by a facile solvothermal method. During this process, TiO2 was coupled with Bi2S3 to generate Bi2S3 sensitized TiO2 nanoparticles, and graphene oxide (GO) was reduced to reduced graphene oxide (RGO), which was uniformly covered with plenty of Bi2S3 and TiO2. The as-prepared samples were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), specific surface areas (BET), X-ray diffraction (XRD), Fourier transform infrared (FTIR), Raman, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL) spectroscopy. The results confirmed that Bi2S3 could act as an optical filter, which could be activated under visible light. And the introduction of Bi2S3 could improve the response of TiO2 nanoparticles for visible light. In addition, the Bi2S3/TiO2 in Bi2S3/TiO2/RGO composites had more uniform dispersion on the surface of graphene with less agglomeration in comparison with the Bi2S3/TiO2. Graphene can provide conductive electron channels for separation of the electrons and inhibit the recombination of electrons and holes. Furthermore, the photocatalytic activity of Bi2S3/TiO2/RGO composites was evaluated through the degradation of methylene blue (MB) under visible light irradiation. The Bi2S3/TiO2/RGO composites showed the highest photocatalytic activity among the referred photocatalysts, with about 3-fold increase in photocatalytic efficiency over TiO2 nanoparticles. The mechanism of high photocatalytic activity was also discussed.

  11. Visible light photo catalytic inactivation of bacteria and photo degradation of methylene blue with Ag/TiO2 nanocomposite prepared by a novel method.

    PubMed

    Tahir, Kamran; Ahmad, Aftab; Li, Baoshan; Nazir, Sadia; Khan, Arif Ullah; Nasir, Tabassum; Khan, Zia Ul Haq; Naz, Rubina; Raza, Muslim

    2016-09-01

    Water purification is one of the worldwide problem and most of the conventional methods are associated with a number of drawbacks. Therefore it is the need of the day to develop new methods and materials to overcome the problem of water purification. In this research work we present a simple and green approach to synthesize silver decorated titanium dioxide (Ag/TiO2) nanocomposite with an efficient photo catalytic activities. Phytochemicals of the Cestrum nocturnum leaf extract were used to synthesize silver nanoparticles (AgNPs), Titanium dioxide (TiO2) and Ag/TiO2 nanocomposite. To confirm the formation, crystal structure, particle size and shape of green synthesized nanoparticles and nanocomposite, they were characterized by UV-visible spectroscopy (UV-vis), X-ray diffraction spectroscopy (XRD), high resolution transmission electron microscopy (HRTEM), Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The AgNPs, TiO2 and Ag/TiO2 were evaluated for photo degradation of methylene blue (MB) and photo inhibition of Bacteria. The bio-synthesized Ag/TiO2 nanocomposite was observed to have strong catalytic activities for photo reduction of MB and photo inactivation of bacteria as compared to bare AgNPs and TiO2. In the presence of Ag/TiO2, 90% of MB was degraded only in 40min of irradiation. Alternatively the bare AgNPs and TiO2 degraded less than 30% and 80% respectively of MB even in more than 100min of irradiation. Similarly the Ag/TiO2 has very strong photo inhibition efficiency towards Escherichia coli and Pseudomonas aeruginosa. The zone of inhibition of irradiated Ag/TiO2 nanocomposites against E. coli and P. aeruginosa was 19mm and 17mm respectively which was two times higher than in dark. These promising photocatalytic activities of nanocomposite may be due to the highly decorated AgNPs over the surface of TiO2.

  12. Degradation of methylene blue using porous WO3, SiO2-WO3, and their Au-loaded analogs: adsorption and photocatalytic studies.

    PubMed

    DePuccio, Daniel P; Botella, Pablo; O'Rourke, Bruce; Landry, Christopher C

    2015-01-28

    A facile sonochemical approach was used to deposit 3-5 nm monodisperse gold nanoparticles on porous SiO2-WO3 composite spheres, as confirmed by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). High-resolution TEM (HR-TEM) and energy dispersive X-ray spectroscopy (EDS) further characterized the supported Au nanoparticles within the Au-SiO2-WO3 composite. These analyses showed isolated Au nanoparticles within both SiO2- and WO3-containing regions. Selective etching of the SiO2 matrix from Au-SiO2-WO3 yielded a pure Au-WO3 material with well-dispersed 10 nm Au nanoparticles and moderate porosity. This combined sonochemical-nanocasting technique has not been previously used to synthesize Au-WO3 photocatalysts. Methylene blue (MB) served as a probe for the adsorption capacity and visible light photocatalytic activity of these WO3-containing catalysts. Extensive MB demethylation (azures A, B, C, and thionine) and polymerization of these products occurred over WO3 under dark conditions, as confirmed by electrospray ionization mass spectrometry (ESI-MS). Photoirradiation of these suspensions led to further degradation primarily through demethylation and polymerization pathways, regardless of the presence of Au nanoparticles. Ring-opening sulfur oxidation to the sulfone was a secondary photocatalytic pathway. According to UV-vis spectroscopy, pure WO3 materials showed superior MB adsorption compared to SiO2-WO3 composites. Compared to their respective nonloaded catalysts, Au-SiO2-WO3 and Au-WO3 catalysts exhibited enhanced visible light photocatalytic activity toward the degradation of MB. Specifically, the rates of MB degradation over Au-WO3 and Au-SiO2-WO3 during 300 min of irradiation were faster than those over their nonloaded counterparts (WO3 and SiO2-WO3). These studies highlight the ability of Au-WO3 to serve as an excellent adsorbant and photodegradation catalyst toward MB.

  13. Nano-Titania Photocatalyst Loaded on W-MCM-41 Support and Its Highly Efficient Degradation of Methylene Blue

    NASA Astrophysics Data System (ADS)

    Shankar, H.; Saravanan, R.; Narayanan, V.; Stephen, A.

    2011-07-01

    Most of the azo dyes produced in textile, printing, paper manufacturing, pulp processing and pharmaceutical industries contain different organic contaminants. These dyes can enter the body through ingestion and the high content in living systems can prove to be carcinogenic. Therefore photocatalytic degradation of such toxic organic compounds in water, in the presence of semiconductor powders has received much attention over the last two decades. Nanocrystalline titanium dioxide, TiO2, is a well studied and commonly used material for photocatalytic applications. However, the control of particle size, monodispersity, large catalytic surface for sufficient adsorption of organic pollutants, recovery and recycle of TiO2 nanoparticles are challenging tasks. Hence in the present study, titania was introduced into the nanopores (2-10 nm size) of MCM-41 to produce stable nanoparticles of uniform size and shape. Further, in order to lengthen the life time of the excited electrons/holes during photoreaction, tungsten atoms were incorporated in to the MCM-41 silica matrix in addition to titania loading.

  14. DNA Electrochemistry with Tethered Methylene Blue

    PubMed Central

    Pheeney, Catrina G.

    2012-01-01

    Methylene blue (MB′), covalently attached to DNA through a flexible C12 alkyl linker, provides a sensitive redox reporter in DNA electrochemistry measurements. Tethered, intercalated MB′ is reduced through DNA-mediated charge transport; the incorporation of a single base mismatch at position 3, 10, or 14 of a 17-mer causes an attenuation of the signal to 62 ± 3% of the well-matched DNA, irrespective of position in the duplex. The redox signal intensity for MB′–DNA is found to be least 3-fold larger than that of Nile blue (NB)–DNA, indicating that MB′ is even more strongly coupled to the π-stack. The signal attenuation due to an intervening mismatch does, however, depend on DNA film density and the backfilling agent used to passivate the surface. These results highlight two mechanisms for reduction of MB′ on the DNA-modified electrode: reduction mediated by the DNA base pair stack and direct surface reduction of MB′ at the electrode. These two mechanisms are distinguished by their rates of electron transfer that differ by 20-fold. The extent of direct reduction at the surface can be controlled by assembly and buffer conditions. PMID:22512327

  15. Methylene Blue Inhibits Caspases by Oxidation of the Catalytic Cysteine.

    PubMed

    Pakavathkumar, Prateep; Sharma, Gyanesh; Kaushal, Vikas; Foveau, Bénédicte; LeBlanc, Andrea C

    2015-09-24

    Methylene blue, currently in phase 3 clinical trials against Alzheimer Disease, disaggregates the Tau protein of neurofibrillary tangles by oxidizing specific cysteine residues. Here, we investigated if methylene blue can inhibit caspases via the oxidation of their active site cysteine. Methylene blue, and derivatives, azure A and azure B competitively inhibited recombinant Caspase-6 (Casp6), and inhibited Casp6 activity in transfected human colon carcinoma cells and in serum-deprived primary human neuron cultures. Methylene blue also inhibited recombinant Casp1 and Casp3. Furthermore, methylene blue inhibited Casp3 activity in an acute mouse model of liver toxicity. Mass spectrometry confirmed methylene blue and azure B oxidation of the catalytic Cys163 cysteine of Casp6. Together, these results show a novel inhibitory mechanism of caspases via sulfenation of the active site cysteine. These results indicate that methylene blue or its derivatives could (1) have an additional effect against Alzheimer Disease by inhibiting brain caspase activity, (2) be used as a drug to prevent caspase activation in other conditions, and (3) predispose chronically treated individuals to cancer via the inhibition of caspases.

  16. Mechanisms for Binding between Methylene Blue and DNA

    NASA Astrophysics Data System (ADS)

    Vardevanyan, P. O.; Antonyan, A. P.; Parsadanyan, M. A.; Shahinyan, M. A.; Hambardzumyan, L. A.

    2013-09-01

    We have used absorption and fl uorimetric methods to study the interaction between methylene blue (MB) and calfthymus DNA. Based on Scatchard analysis of the experimental data, we plotted the methylene blue-DNA binding curve. This curve consists of two linear sections, which indicates two types of interaction, for which we determined the constants K and the number of binding sites n for binding of this ligand to DNA. Comparison of the data obtained with analogous values found for interaction between ethidium bromide and DNA allowed us to conclude that there are two modes of interaction between methylene blue and DNA: strong binding (semi-intercalation) and weak binding (electrostatic).

  17. CoTiO3/Ag3VO4 composite: A study on the role of CoTiO3 and the active species in the photocatalytic degradation of methylene blue.

    PubMed

    Wangkawong, Kanlayawat; Phanichphant, Sukon; Tantraviwat, Doldet; Inceesungvorn, Burapat

    2015-09-15

    The role of CoTiO3 and the possible active species in the methylene blue (MB) degradation over the visible-light-driven CoTiO3/Ag3VO4 catalyst have firstly been investigated in this work. CoTiO3 is found to play important roles in enhancing the visible light-harvesting ability of the composite and increasing electron-hole separation efficiency due to the hybrid effect between Ag3VO4 and CoTiO3. The indirect probe experiments reveal that CoTiO3/Ag3VO4 heterostructure provides large amount of active species, therefore a high photocatalytic activity could be obtained. The results clearly suggest that the photocatalytic MB degradation over this hybrid catalyst is mainly governed by direct hole oxidation.

  18. Methylene blue treatment in experimental ischemic stroke: a mini review

    PubMed Central

    Jiang, Zhao; Duong, Timothy Q

    2016-01-01

    Stroke is a leading cause of death and long-term disability. Methylene blue, a drug grandfathered by the Food and Drug Administration with a long history of safe usage in humans for treating methemoglobinemia and cyanide poisoning, has recently been shown to be neuroprotective in neurodegenerative diseases and brain injuries. The goal of this paper is to review studies on methylene blue in experimental stroke models. PMID:27042692

  19. Hydrotalcite-TiO2 magnetic iron oxide intercalated with the anionic surfactant dodecylsulfate in the photocatalytic degradation of methylene blue dye.

    PubMed

    Miranda, Liany D L; Bellato, Carlos R; Milagres, Jaderson L; Moura, Luciano G; Mounteer, Ann H; de Almeida, Marciano F

    2015-06-01

    The new magnetic photocatalysts HT/TiO2/Fe and HT-DS/TiO2/Fe, modified with the anionic surfactant sodium dodecylsulfate (DS) were successfully synthesized in this work. Titanium dioxide (anatase) followed by iron oxide were deposited on the hydrotalcite support. Several catalyst samples were prepared with different amounts of titanium and iron. The photocatalysts were characterized by infrared and Raman spectroscopy, X-ray diffraction, scanning electron microscopy. Photocatalytic performance was analyzed by UV-visible radiation (filter cutoff, λ > 300 nm) of an aqueous solution (24 mg/L) of methylene blue (MB). The most efficient catalyst was obtained at an iron oxide:TiO2 molar ratio of 2:3. This catalyst showed high photocatalytic activity, removing 96% of the color and 61% of total organic carbon from the MB solution after 120 min. It was easily removed from solution after use because of its magnetic properties. The reuse of the HT-DS/TiO2/Fe23 catalyst was viable and the catalyst was structurally stable for at least four consecutive photocatalytic cycles.

  20. On structure and methylene blue degradation activity of an Aurivillius-type photocatalyst of Bi4V2O11 nanoparticles

    NASA Astrophysics Data System (ADS)

    Lu, Yuting; Pu, Yinfu; Wang, Jing; Qin, Chuangxiang; Chen, Cuili; Seo, Hyo Jin

    2015-08-01

    Aurivillius-type photocatalyst of Bi4V2O11 nanoparticles with an average particle size of 45 nm was prepared by the modified Pechini method. The sample was investigated by X-ray powder diffraction (XRD) and the structural refinement. The nanoparticles were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopic (XPS) and UV-vis absorption spectrum. Bi4V2O11 nanoparticles show an efficient absorption in the UV-vis light wavelength region with a narrowed band gap energy of 2.08 eV and an indirect allowed electronic transition. The photocatalytic activities of Bi4V2O11 nanoparticles were evaluated by photodegradation of methylene blue (MB) under visible-light irradiation in air atmosphere. These results indicate that Bi4V2O11 could be a potential photocatalyst driven by visible-light. Hybridization of the 6s and 6p orbitals of Bi3+ and the resulting lone electron pair yields interesting properties. The effective photocatalytic activity was discussed on the base of the crystal structure characteristic such as polar (VO3.5□0.5)2- anionic groups, Aurivillius-type (Bi2O2)2+ layers and long distance of the nearest V-V in the lattices, etc.

  1. Fabrication of TiO2/Ti electrode by laser-assisted anodic oxidation and its application on photoelectrocatalytic degradation of methylene blue.

    PubMed

    Li, Jiaqing; Zheng, Lei; Li, Luoping; Xian, Yuezhong; Jin, Litong

    2007-01-02

    A TiO2/Ti mesh electrode by laser calcination was prepared in this article. The resulting TiO2 film was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS), and it illuminated that the prepared electrode mainly consisted of anatase TiO2 nanoparticles on its surface and exhibited a superior photocatalytic activity. The photodegradation of methylene blue (MB) using the proposed electrode under different experimental conditions was investigated in terms of both UV absorbance at 664 nm and chemical oxygen demand (COD) removal. The electrical bias applied in photoelectrocatalytic (PEC) oxidation was also studied. The experimental results showed that under the optimal potential of +0.50 V (versus SCE), UV absorbance and COD removal during the photodegradation of MB by the proposed TiO2/Ti mesh electrode were 97.3% and 87.0%, respectively. Through the comparison between photocatalytic (PC) oxidation and photoelectrocatalytic (PEC) oxidation, it was found that PEC oxidation was a convenient and effective way to mineralize the organic matters and that laser-treated photoelectrode exceeded the oven-treated one.

  2. Adsorption and photocatalytic degradation of methylene blue on Zn 1- xCu xS nanoparticles prepared by a simple green method

    NASA Astrophysics Data System (ADS)

    Naghiloo, S.; Habibi-Yangjeh, A.; Behboudnia, M.

    2011-01-01

    Nanoparticles of Zn 1- xCu xS with various dopant contents (0 ≤ x ≤ 0.15) were prepared in water by refluxing for 90 min at about 95 °C. Powder X-ray diffraction (XRD) patterns of the nanoparticles demonstrate that loading of Cu 2+ ions does not change the crystal structure of ZnS. Scanning electron microscopy (SEM) images demonstrate that size of the nanoparticles decreases with increasing Cu 2+ ions. UV-Vis diffuse reflectance spectra (DRS) of the nanoparticles show significant absorption in visible light region. Adsorption capacity of the nanoparticles for methylene blue (MB) increases with mole fraction of copper ions. Photocatalytic activity of the nanoparticles toward photodegradation of MB was evaluated under visible light irradiation. The results indicate that Zn 0.85Cu 0.15S nanoparticles exhibit highest photocatalytic activity among the prepared samples. Moreover, effects of refluxing time applied for preparation of the nanoparticles and calcination temperature were investigated.

  3. Preparation of reduced graphene oxide/meso-TiO2/AuNPs ternary composites and their visible-light-induced photocatalytic degradation n of methylene blue

    NASA Astrophysics Data System (ADS)

    Yang, Yongfang; Ma, Zheng; Xu, Lidong; Wang, Hefang; Fu, Nian

    2016-04-01

    Reduced graphene oxide/meso-TiO2/AuNPs (RGO/meso-TiO2/AuNPs) ternary composites were prepared via the addition of graphene oxide to the dispersion of meso-TiO2/AuNPs under hydrothermal conditions. The structure and the morphology of the RGO/meso-TiO2/AuNPs materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The photocatalytic activity of RGO/meso-TiO2/AuNPs was evaluated by degradation of methyl blue (MB) under visible-light illumination. The ternary composites present an extended light absorption range, efficient charge separation properties, high adsorption ability for MB and high photocatalytic degradation activity of MB compared to the meso-TiO2 and meso-TiO2/AuNPs.

  4. An approach to utilize the artificial high power LED UV-A radiation in photoreactors for the degradation of methylene blue.

    PubMed

    Betancourt-Buitrago, L A; Vásquez, C; Veitia, L; Ossa-Echeverry, O; Rodriguez-Vallejo, J; Barraza-Burgos, J; Marriaga-Cabrales, N; Machuca-Martínez, F

    2017-01-18

    Utilization of UV LED light is trending in the development of photoreactors for pollutant treatment. In this study, two different geometries were studied in the degradation of methylenebBlue (MB) using high power UVA LED as a source of light. The dosage, initial concentration, electric power, and H2O2 addition were evaluated in the two geometries: a mini CPC (Cilindrical Parabolic Collector) and a vertical cylindrical with external irradiation both coupled with LED UVA. Best degradation was obtained for 0.3 g L(-1) TiO2, 40 min, and 15 ppm of MB of initial concentration in the standard batch reactor. It was found that the best system was a cpc geometry. Also, hydrogen peroxide was used as an electron acceptor and 97% degradation was obtained in 30 min with 10 mM H2O2 and 0.4 g TiO2/L. Power of the LEDs was also evaluated and it was found that 20 W m(-2) is the best operational condition to achieve the best MB degradation avoiding the oxidant species recombination.

  5. Study of catalytic reduction and photodegradation of methylene blue by heterogeneous catalyst.

    PubMed

    Sohrabnezhad, Sh

    2011-10-15

    The photocatalytic degradation of methylene blue is investigated in aqueous solution containing CoS/nanoAl-MCM-41 photocatalyst under visible light. The catalyst is characterized by X-ray diffraction (XRD), UV-vis diffused reflectance spectra (UV-vis DRS) and transmission electron microscopy (TEM) techniques. The effect of CoS, nanoAl-MCM-41 support and different wt% of CoS over the support on the photocatalytic degradation and influence of parameters such as CoS loading, catalyst amount, pH and initial concentration of methylene blue on degradation are evaluated. Hypsochromic effects (i.e. blue shifts of spectral bands) resulting from N-demethylation of the dimethylamino group in methylene blue occurs in presence of CoS/nanoAl-MCM-41 under ambient condition. Meanwhile, the bleaching of methylene blue MB, by sulfide ion, in an aqueous solution is studied in the presence nanoAl-MCM-41 catalyst. In the presence of sulfide ions, MB is bleached to its colorless leuco (LMB) and MBH(2)(+) forms. In an acidified solution (pH<2) the bleaching process generates LMB and by changing pH between 2.0 and 7.0 bleaching of MB dye to MBH(2)(+) form is observed. Using nanoAl-MCM-41 with encapsulated CoS nanoparticles only causes demethylation of MB in aqueous solution.

  6. Study of catalytic reduction and photodegradation of methylene blue by heterogeneous catalyst

    NASA Astrophysics Data System (ADS)

    Sohrabnezhad, Sh.

    2011-10-01

    The photocatalytic degradation of methylene blue is investigated in aqueous solution containing CoS/nanoAl-MCM-41 photocatalyst under visible light. The catalyst is characterized by X-ray diffraction (XRD), UV-vis diffused reflectance spectra (UV-vis DRS) and transmission electron microscopy (TEM) techniques. The effect of CoS, nanoAl-MCM-41 support and different wt% of CoS over the support on the photocatalytic degradation and influence of parameters such as CoS loading, catalyst amount, pH and initial concentration of methylene blue on degradation are evaluated. Hypsochromic effects (i.e. blue shifts of spectral bands) resulting from N-demethylation of the dimethylamino group in methylene blue occurs in presence of CoS/nanoAl-MCM-41 under ambient condition. Meanwhile, the bleaching of methylene blue MB, by sulfide ion, in an aqueous solution is studied in the presence nanoAl-MCM-41 catalyst. In the presence of sulfide ions, MB is bleached to its colorless leuco (LMB) and MBH 2+ forms. In an acidified solution (pH < 2) the bleaching process generates LMB and by changing pH between 2.0 and 7.0 bleaching of MB dye to MBH 2+ form is observed. Using nanoAl-MCM-41 with encapsulated CoS nanoparticles only causes demethylation of MB in aqueous solution.

  7. A novel P-doped g-C3N4/Zn0.8Cd0.2S composite photocatalyst for degradation of methylene blue under simulated sunlight

    NASA Astrophysics Data System (ADS)

    Tian, Wei; Li, Naixu; Zhou, Jiancheng

    2016-01-01

    P-doped g-C3N4/Zn0.8Cd0.2S (PCN/ZS) heterostructures have been constructed via a two-pot method and investigated as catalysts for photocatalytic degradation of methylene blue (MB) under simulated sunlight. XRD, UV-vis spectrometry, FT-IR, PL, TEM, and EDS were used to provide structure information of the as-prepared samples involving the formation of the ZS solid solution, the existence of the heterostructure between PCN and ZS, the graphite-like structure of PCN and successful incorporation of P into the framework of CN. The enhanced catalytic performance of PCN/ZS for the degradation of MB compared with pure PCN and ZS benefited from elevated light-harvesting property, favorable transport and separation efficiency of photoinduced charge carriers through the construction of the heterojunction originated from in situ growth of the ZS solid solution on PCN. The degradation efficiency (D) had a maximum of 91.3% with a given mass ratio of PCN to ZS (y = 0.5 wt%). h+ and rad O2- proved the main reactive species for MB degradation, based on which the possible reaction path was proposed.

  8. Photocatalytic degradation of methyl orange, methylene blue and rhodamine B with AgCl nanocatalyst synthesised from its bulk material in the ionic liquid [P6 6 6 14]Cl.

    PubMed

    Rodríguez-Cabo, Borja; Rodríguez-Palmeiro, Iago; Corchero, Raquel; Rodil, Rosario; Rodil, Eva; Arce, Alberto; Soto, Ana

    2017-01-01

    The photocatalytic degradation of wastewater containing three industrial dyes belonging to different families, methyl orange (MO), methylene blue (MB) and Rhodamine B (RhB), was studied under UV-Vis irradiation using synthesised silver chloride nanoparticles. The nanocatalyst was prepared by a dissolution/reprecipitation method starting from the bulk powder and the ionic liquid trihexyl(tetradecyl)phosphonium chloride, [P6 6 6 14]Cl, without addition of other solvents. The obtained catalyst was characterised by UV-Vis absorbance, X-ray powder diffraction, transmission electron microscopy and scanning electron microscopy. The decolourisation of the samples was studied by UV-Vis absorbance at the corresponding wavelength. Starting from 10 ppm dye solutions and 1 g L(-1) of the synthesised AgCl nanoparticles, degradation efficiencies of 98.4% for MO, 98.6% for MB and 99.9% for RhB, were achieved in 1 h. The degradation mechanisms for the different dyes were studied. Comparison with other frequently used nanocatalysts, namely P-25 Degussa, TiO2 anatase, Ag and ZnO, highlights the strong catalytic activity of AgCl nanoparticles. Under the same experimental conditions, these nanoparticles led to higher (more than 10%) and faster degradations.

  9. [Enhanced reductive decoloration of methylene blue by polyacrylic acid modified zero-valent iron nanoparticles].

    PubMed

    He, Jing; Wang, Xiang-Yu; Wang, Pei; Liu, Kun-Qian

    2015-03-01

    Nano zerovalent iron ( NZVI) technology has attracted tremendous amount of interests for degrading a number of environmental contaminants found both in surface water and underground water. However, these nanoscale particles are prone to aggregate, which may result in the decrease of its reactivity in liquid phase. Iron nanoparticles (Fe NPs) modified with polyacrylic acid (PAA) has enhanced the dispersion of NZVI and reduced its agglomeration. For the first time, PAA modified NPs (PAA-Fe NPs) were used for degradation of methylene blue in water phase. The PAA-Fe NPs prepared were characterized in terms of TEM, SEM, XRD and specific surface area. The results indicated that, the surface area of PAA-Fe NPs was increased, compared with unmodified pristine zero-valent iron NPs, and PAA-Fe NPs were smoother with smaller particle size. With addition of 0.1 g x L(-1) of PAA, the decolorization efficiency of methylene blue by PAA-Fe NPs was 98.84% in 60 min, which was 27.32% higher than that of pristine Fe NPs. Decolorization efficiencies were also affected by initial pH value, initial concentration of methylene blue, dosage of PAA-Fe NPs, and degradation temperature. Kinetic analyses based on the experimental data illustrated that the decolorization reaction of methylene blue fitted well to the pseudo first-order kinetics model.

  10. Adsorption of methylene blue from aqueous solution by graphene.

    PubMed

    Liu, Tonghao; Li, Yanhui; Du, Qiuju; Sun, Jiankun; Jiao, Yuqin; Yang, Guangming; Wang, Zonghua; Xia, Yanzhi; Zhang, Wei; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai

    2012-02-01

    Graphene was prepared using a modified Hummers' method. The physico-chemical properties of graphene were characterized by TEM, BET specific surface area, FTIR, Raman and XRD measurements. The effect factors including pH, contact time, temperature and dosage on the adsorption properties of methylene blue onto graphene were investigated. The experimental data of isotherm followed the Langmuir isotherm model better than the Freundlich model. The maximum adsorption capacity obtained from Langmuir isotherm equation at 293 K was 153.85 mg/g, indicating graphene is a good adsorbent for the adsorption of MB. The kinetic study illustrated that the adsorption of methylene blue onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of methylene blue onto graphene was an endothermic and spontaneous process.

  11. Localization of methylene blue paramolybdate in vitally stained nerves.

    PubMed

    Chapman, D M

    1982-01-01

    Methylene blue taken up by living neurons can be preserved for electron microscopy in a fixative containing osmium tetroxide and ammonium paramolybdate at pH 5.2. Paramolybdate is the buffer, precipitating agent and main osmotic ingredient; it does not function as an electron stain unless methylene blue is present. The low pH keeps the dye/paramolybdate complex from dissolving. Neither the low pH nor drastic dehydration from water to absolute ethanol harm the tissue. The staining mechanism involves cationic methylene blue associating with anionic structures such as microtubules and neurofilaments in the living cell; during fixation paramolybdate forms a precipitate with the dye at the staining sites. This fixative does not preserve microtubules unless they are first vitally stained.

  12. Reduction of methylene blue by thiocyanate: kinetic and thermodynamic aspects.

    PubMed

    Pande, Surojit; Ghosh, Sujit Kumar; Nath, Sudip; Praharaj, Snigdhamayee; Jana, Subhra; Panigrahi, Sudipa; Basu, Soumen; Pal, Tarasankar

    2006-07-01

    This article reports the reduction of methylene blue (MB) by thiocyanate ions (SCN(-)) in aqueous and micellar solutions. Thiocyanate ions are found to be an effective reducing agent for the decolorization of methylene blue under ambient condition. Effects of salting-in and salting-out agents have been investigated for real-time application in the reduction process. The salting-in agent urea has been found to uniquely enhance the rate of the reduction of MB by thiocyanate ion in the presence of micelles. Again, the catalytic activity of nanoparticles in the reduction of MB has also been studied. Detailed kinetic and thermodynamic aspects have been considered to realize the interaction between methylene blue and thiocyanate. Kinetic studies revealed that the reaction is reversible and follows first-order reaction kinetics.

  13. Analysis of methylene blue in human urine by capillary electrophoresis.

    PubMed

    Borwitzky, Holger; Haefeli, Walter E; Burhenne, Jürgen

    2005-11-05

    A capillary electrophoresis method for the determination of the dye methylene blue (tetramethylthionine, MB) in human urine depending on liquid/liquid-extraction and diode array detection has been developed, validated, and applied to samples of healthy individuals, who had been dosed with methylene blue within clinical studies. After extraction with dichloromethane and sodium hexanesulfonate, sample extracts were measured on an extended light path capillary. The dye was detected simultaneously at 292 and 592 nm using methylene violet 3 RAX as internal standard. The limit of quantification was 1.0 microg/ml. The accuracy of the method varied between -15.2 and +0.8% and the precision ranged from 2.0 to 12.0%. The method was linear at least within 1.0 and 60 microg/ml. In contrast to earlier indirect determinations no leuco methylene blue (LMB) was directly detected in urine, whereas in aqueous test solutions containing surplus amounts of ascorbic acid leuco methylene blue was well separated from MB in a single run.

  14. Borax methylene blue: a spectroscopic and staining study.

    PubMed

    Donaldson, P T; Russo, A; Reynolds, C; Lillie, R D

    1978-07-01

    Borax methylene blue is quite stable at room temperatures of 22-25 C. At 30 C polychroming is slow; during 50 days in a water bath at this temperature the absorption peak moves from 665 to 656 nm. At 35 C, the absorption peak reaches 660 nm in 7 days, 654 nm in 14. At 60 C polychroming is rapid, the absorption peak reaching 640-620 nm in 3 days. When the pH of the borax methylene blue solutions, normally about 9.0, is adjusted to pH 6.5, the absorption peak remains at 665 nm even when incubated at 60 C for extended periods. When used as a blood stain 0.4 ml borax methylene blue (1% methylene blue in 1% borax), 4 ml acetone, 2 ml borax-acid phosphate buffer to bring the solution to pH 6.5, and distilled water to make 40 ml, with 0.2 ml 1% eosin added just before using, an excellent Nocht-Giemsa type stain is achieved after 30 minutes staining. The material plasmodia P. falciparum, P. vivax, and P. berghei stain moderate blue with dark red chromatin and green to black pigment granules. The study confirms Malachowski's 1891 results and explains Gautier's 1896-98 failure to duplicate it.

  15. Extinction Memory Improvement by the Metabolic Enhancer Methylene Blue

    ERIC Educational Resources Information Center

    Gonzalez-Lima, F.; Bruchey, Aleksandra K.

    2004-01-01

    We investigated whether postextinction administration of methylene blue (MB) could enhance retention of an extinguished conditioned response. MB is a redox compound that at low doses elevates cytochrome oxidase activity, thereby improving brain energy production. Saline or MB (4 mg/kg intraperitoneally) were administered to rats for 5 d following…

  16. Methylene Blue-Ascorbic Acid: An Undergraduate Experiment in Kinetics.

    ERIC Educational Resources Information Center

    Snehalatha, K. C.; And Others

    1997-01-01

    Describes a laboratory exercise involving methylene blue and L-ascorbic acid in a simple clock reaction technique to illustrate the basic concepts of chemical kinetics. If stock solutions are supplied and each type of experiment takes no more than half an hour, the entire investigation can be completed in three practical sessions of three hours…

  17. Solar photocatalytic decolorization of methylene blue in water.

    PubMed

    Kuo, W S; Ho, P H

    2001-10-01

    In this study, a photocatalytic decolorization system equipped with immobilized TiO2 and illuminated by solar light was used to remove the color of wastewater. To examine the decoloring efficiency of this system, photocatalytic decolorization of an organic dye such as methylene blue was studied as an example. The effects of light source, pH, as well as the initial concentration of dye were also investigated. It was observed that the solution of methylene blue could be almost completely decolorized by the solar light/TiO2 film process while there was about 50% color remaining with solar irradiation only. In addition, it was found that the decoloring efficiency of solution was higher with solar light irradiation than with artificial UV light irradiation, even though the artificial UV light source supplied higher UV intensity at 254 nm. The color removal rate of methylene blue with solar light irradiation was almost twice that of artificial UV light irradiation. This phenomena was mainly attributed to that some visible light range of solar light was useful for exciting the methylene blue molecules adsorbed on TiO2 film, leading to a photosensitization process undergoing and decoloring efficiency promoted. This solar-assisted photocatalytic device showed potential application for decoloring organic dyes in wastewater.

  18. γ-Fe{sub 2}O{sub 3} nanoparticles: An easily recoverable effective photo-catalyst for the degradation of rose bengal and methylene blue dyes in the waste-water treatment plant

    SciTech Connect

    Dutta, Amit Kumar; Maji, Swarup Kumar; Adhikary, Bibhutosh

    2014-01-01

    Graphical abstract: - Highlights: • γ-Fe{sub 2}O{sub 3} NPs from a single-source precursor and characterized by XRD, TEM, UV–vis spectra. • The NPs were tested as effective photocatalyst toward degradation of RB and MB dyes. • The possible pathway of the photocatalytic decomposition process has been discussed. • The active species, OH·, was detected by TA photoluminescence probing techniques. - Abstract: γ-Fe{sub 2}O{sub 3} nanoparticles (NPs) were synthesized from a single-source precursor complex [Fe{sub 3}O(C{sub 6}H{sub 5}COO){sub 6}(H{sub 2}O){sub 3}]NO{sub 3} by a simple thermal decomposition process and have been characterized by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM) and UV–vis spectroscopic techniques. The NPs were highly pure and well crystallized having hexagonal morphology with an average particle size of 35 nm. The prepared γ-Fe{sub 2}O{sub 3} (maghemite) NPs show effective photo-catalytic activity toward the degradation of rose bengal (RB) and methylene blue (MB) dyes under visible light irradiation and can easily be recoverable in the presence of magnetic field for successive re-uses. The possible photo-catalytic decomposition mechanism is discussed through the detection of hydroxyl radical (OH·) by terephthalic acid photo-luminescence probing technique.

  19. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Methylene blue-containing drugs for use in animals... Decisions § 500.27 Methylene blue-containing drugs for use in animals. (a) New information requires a re- evaluation of the status of drugs containing methylene blue (tetramethylthionine chloride) for oral use...

  20. Nitroreductase-triggered activation of a novel caged fluorescent probe obtained from methylene blue.

    PubMed

    Bae, Jungeun; McNamara, Louis E; Nael, Manal A; Mahdi, Fakhri; Doerksen, Robert J; Bidwell, Gene L; Hammer, Nathan I; Jo, Seongbong

    2015-08-18

    A near-infrared fluorescent probe based on methylene blue (p-NBMB) was developed for the detection of nitroreductase. Conjugating methylene blue with a p-nitrobenzyl moiety enables it to be activated by nitroreductase-catalyzed 1,6-elimination, resulting in the release of an active methylene blue fluorophore.

  1. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Methylene blue-containing drugs for use in animals... Decisions § 500.27 Methylene blue-containing drugs for use in animals. (a) New information requires a re- evaluation of the status of drugs containing methylene blue (tetramethylthionine chloride) for oral use...

  2. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Methylene blue-containing drugs for use in animals... Decisions § 500.27 Methylene blue-containing drugs for use in animals. (a) New information requires a re- evaluation of the status of drugs containing methylene blue (tetramethylthionine chloride) for oral use...

  3. Kinetics of Methylene Blue Reduction by Ascorbic Acid

    NASA Astrophysics Data System (ADS)

    Mowry, Sarah; Ogren, Paul J.

    1999-07-01

    The redox reactions of methylene blue (MB+) often occur on a time scale of a few seconds to minutes. They may be followed visually for qualitative interpretations and spectrophotometrically for quantitative determinations. The experimental simplicity of MB+ reaction systems has also occasionally led to erroneous conclusions based upon oversimplified data treatment and assumptions. This paper compares spectrophotometric studies of MB+ reduction by ascorbic acid at low pH with previous conclusions based upon visual determinations of color loss. Spectrophotometric studies of the temporal decay of MB+ absorbance at 665 nm show that the reaction is first order in MB+, ascorbic acid, and HCl. A slower reaction occurs with only MB+ and ascorbic acid present. Regeneration of MB+ color by reaction with dissolved oxygen, the "blue bottle" reaction, is particularly significant when the reaction with ascorbic acid is slow. Methylene blue chemistry continues to provide a wealth of examples suitable for undergraduate kinetics studies.

  4. Heterogeneous photocatalysis of methylene blue over titanate nanotubes: effect of adsorption.

    PubMed

    Xiong, Lin; Sun, Weiling; Yang, Ye; Chen, Cheng; Ni, Jinren

    2011-04-01

    Titanate nanotubes were synthesized with hydrothermal reaction using TiO(2) and NaOH as the precursors and subsequent calcination at 400°C for 2h. The products were characterized with SEM and XRD. Adsorption and photocatalysis of methylene blue over titanate nanotubes and TiO(2) were investigated. The results indicated that titanate nanotubes exhibited a better photocatalytic degradation of methylene blue in a simultaneous adsorption and photodegradation system than that in equilibrium adsorption followed by a photodegradation system, whereas TiO(2) showed no significant differences in photocatalytic activity in the two systems. The methylene blue overall removal efficiency over TNTs in the first system even exceeded that over TiO(2). The different catalytic performances of titanate nanotubes in the two systems were tentatively attributed to different effects of adsorption of methylene blue, i.e., the promoting effect in the former and the inhibition effect in the latter. Decantation experiments showed that the titanate nanotube photocatalyst could be easily separated from the reaction medium by sedimentation. Thus titanate nanotubes with high sedimentation rates and concurrent adsorption represent a new catalyst system with a strong potential for commercial applications.

  5. Spinel NixZn1-xFe2O4 (0.0 ≤ x ≤ 1.0) nano-photocatalysts: Synthesis, characterization and photocatalytic degradation of methylene blue dye

    NASA Astrophysics Data System (ADS)

    Padmapriya, G.; Manikandan, A.; Krishnasamy, V.; Jaganathan, Saravana Kumar; Antony, S. Arul

    2016-09-01

    Spinel NixZn1-xFe2O4 (x = 0.0 to 1.0) nanoparticles were successfully synthesized by a simple microwave combustion method (MCM) using metal nitrates as raw materials and glycine as the fuel. The structural, morphological and opto-magnetic properties of the spinel NixZn1-xFe2O4 ferrites were determined by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray (EDX) spectroscopy, high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED) pattern, UV-Visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM). Powder XRD, and EDX analysis was confirmed the formation of pure phase of spinel ferrites. HR-SEM and HR-TEM analysis was confirmed the formation of sphere like-particle morphology of the samples with smaller agglomeration. VSM analysis clearly showed the superparamagnetic and ferromagnetic nature of the samples. The Ms value is 3.851 emu/g for undoped ZnFe2O4 sample and it increased with increase in Ni content. Photo-catalytic degradation (PCD) of methylene blue (MB) dye using the samples were carried out and observed good PCD results.

  6. Methylene blue adsorption on graphene oxide/calcium alginate composites.

    PubMed

    Li, Yanhui; Du, Qiuju; Liu, Tonghao; Sun, Jiankun; Wang, Yonghao; Wu, Shaoling; Wang, Zonghua; Xia, Yanzhi; Xia, Linhua

    2013-06-05

    Graphene oxide has been used as an adsorbent in wastewater treatment. However, the dispersibility in aqueous solution and the biotoxicity to human cells of graphene oxide limits its practical application in environmental protection. In this research, a novel environmental friendly adsorbent, calcium alginate immobilized graphene oxide composites was prepared. The effects of pH, contact time, temperature and dosage on the adsorption properties of methylene blue onto calcium alginate immobilized graphene oxide composites were investigated. The equilibrium adsorption data were described by the Langmuir and Freundlich isotherms. The maximum adsorption capacity obtained from Langmuir isotherm equation was 181.81 mg/g. The pseudo-first order, pseudo-second order, and intraparticle diffusion equation were used to evaluate the kinetic data. Thermodynamic analysis of equilibriums indicated that the adsorption reaction of methylene blue onto calcium alginate immobilized graphene oxide composites was exothermic and spontaneous in nature.

  7. Simplified Method for Preparing Methylene-Blue-Sensitized Dichromated Gelatin

    NASA Astrophysics Data System (ADS)

    Kurokawa, Kazumasa; Koike, Satoshi; Namba, Sinji; Mizuno, Toru; Kubota, Toshihiro

    1998-05-01

    Methylene-blue-sensitized dichromated gelatin (MBDCG) is a suitable material for recording full-color holograms in a single layer. However, a drying process in an ammonia atmosphere is necessary to prepare the MBDCG plate. This process is time-consuming and unstable. A simplified method for preparing the MBDCG plate is presented in which the MBDCG can be dried without ammonia. Elimination of the drying process is possible when the methylene blue in MBDCG does not separate. This is achieved by a decrease in the concentration of dichromate in the photosensitized solution and the addition of an ammonia solution to the photosensitized solution. Last, the gelatin is allowed to gel. A Lippmann color hologram grating with a diffraction efficiency of more than 80% is obtained by use of this MBDCG.

  8. Methylene blue treatment for resistant shock following renal transplantation.

    PubMed

    Hershman, Eli; Hadash, Amir; Attias, Ori; Ben-Ari, Josef

    2015-11-01

    We report a case of a 19-year-old female with a history of hyperoxaluria type 1 and renal failure. The patient presented for a second renal transplantation 17 years after her first combined liver and kidney transplantation. Postoperative shock was highly resistant to fluids and required massive pharmacologic hemodynamic support. Vasoplegic shock was the presumed diagnosis, and methylene blue was utilized as a rescue therapy, with a rapid hemodynamic response and no apparent side effects.

  9. Spectrophotometric determination of chromium (VI) with Methylene Blue.

    PubMed

    Kamburova, M

    1993-05-01

    The interaction of Cr(VI) and the thiazine dye Methylene Blue has been examined. The ion-associate formed is extractable into 1,2-dichlorethane. The optimum conditions have been established, and values obtained for the conditional extraction constant K'(ex), distribution constant K'(D) and association constant beta'. A sensitive and selective method for determination of microquantities of Cr(VI) in soils and alloys is suggested.

  10. Tailored synthesis of CuS nanodisks from a new macrocyclic precursor and their efficient catalytic properties on methylene blue dye degradation

    NASA Astrophysics Data System (ADS)

    Islam, D. A.; Chakraborty, A.; Bhattacharya, B.; Sarkar, U.; Acharya, H.

    2016-05-01

    In this study, CuS nanodisks have been synthesized from a tetraaza (N4) macrocyclic complex precursor by a facile wet chemical method. The crystallinity and morphology of the as-synthesized products were characterized by X-ray diffraction and transmission electron microscopy, which confirm a phase pure crystalline CuS nanostructures with 15 to 20 nm in dimension with 5 nm thickness. A possible formation mechanism and growth process of the CuS nanodisks are discussed using thiourea and tetraaza ligand as the sulfur donor and stabilizing agent, respectively. Cyclic N4 ligand also acts as a binding agent to template-guide the oriented growth of CuS nanodisks. The optimized geometry of ligands and complexes was calculated using B3YLP functional, which indicates that the HOMO in the complex located on metal center and N atoms are weakly bonded to the metal center. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than under dark in the presence of H2O2. The C t/ C 0 plot as a function of time displays the higher MB degradation activity of CuS nanoparticles with H2O2. The recycle stability of CuS nanoparticles was even found to be >80 % after five cycles studied by repeating the MB degradation with same CuS nanoparticles sample.

  11. [Adsorption of methylene blue from water by the biochars generated from crop residues].

    PubMed

    Xu, Ren-Kou; Zhao, An-Zhen; Xiao, Shuang-Cheng; Yuan, Jin-Hua

    2012-01-01

    Biochars were prepared from straws of rice, peanut and soybean and rice hull using a low temperature pyrolysis method and adsorption of methylene blue by these biochars were investigated with batch and leaching experiments. Results indicated that biochars have high adsorption capacity for methylene blue and followed the order: rice straw char > soybean straw char > peanut straw char > rice hull char. This order is generally consistent with the amount of negative charge and specific surface area of these biochars. While methylene blue was mainly adsorbed specifically by the biochars, because the adsorption of methylene blue increased with the increase of ionic strength and the adsorption led to the shift of zeta potential of biochar particles to positive value direction. Langmuir equation fitted the adsorption isotherms well and can be used to describe the adsorption behaviors of methylene blue by the biochars. The maximum adsorption capacity of methylene blue predicted by langmuir equation was 196.1, 169.5, 129.9 and 89.3 mmol x kg(-1) for rice straw char, soybean straw char, peanut straw char and rice hull char, respectively. Leaching experiments show that rice hull char of 156 g can remove methylene blue from 30 L water containing 0.3 mmol x L(-1) of methylene blue completely and the cumulative amount of methylene blue absorbed by the biochar reaches 57.7 mmol x kg(-1). The biochars can be used as efficient adsorbents to remove methylene blue from waste water of dye.

  12. Rapid degradation of methylene blue in a novel heterogeneous Fe3O4 @rGO@TiO2-catalyzed photo-Fenton system

    PubMed Central

    Yang, Xiaoling; Chen, Wei; Huang, Jianfei; Zhou, Ying; Zhu, Yihua; Li, Chunzhong

    2015-01-01

    Herein, a ternary nanocomposite with TiO2 nanoparticles anchored on reduced graphene oxide (rGO)-encapsulated Fe3O4 spheres (Fe3O4@rGO@TiO2) is presented as a high efficient heterogeneous catalyst for photo-Fenton degradation of recalcitrant pollutants under neutral pH. Fe3O4@rGO@TiO2 was synthesized by depositing TiO2 nanoparticles on the surface of the Fe3O4 spheres wrapped by graphene oxide (GO) which was obtained by an electrostatic layer-by-layer method. This as-prepared catalyst reflected good ferromagnetism and superior stability which makes it convenient to be separated and recycled. Due to the synergic effects between the different components composed the catalyst, swift reduction of Fe3+ can be achieved to regenerate Fe2+. Fe3O4@rGO@TiO2 exhibited enhancing catalytic activity for the degradation of azo-dyes compared with Fe3O4, Fe3O4@SiO2@TiO2 or SiO2@rGO@TiO2, further conforming the rapid redox reaction between Fe2+ and Fe3+. All these merits indicate that the composite catalyst possesses great potential for visible-light driven destruction of organic compounds. PMID:26000975

  13. Rapid degradation of methylene blue in a novel heterogeneous Fe3O4 @rGO@TiO2-catalyzed photo-Fenton system.

    PubMed

    Yang, Xiaoling; Chen, Wei; Huang, Jianfei; Zhou, Ying; Zhu, Yihua; Li, Chunzhong

    2015-05-22

    Herein, a ternary nanocomposite with TiO2 nanoparticles anchored on reduced graphene oxide (rGO)-encapsulated Fe3O4 spheres (Fe3O4@rGO@TiO2) is presented as a high efficient heterogeneous catalyst for photo-Fenton degradation of recalcitrant pollutants under neutral pH. Fe3O4@rGO@TiO2 was synthesized by depositing TiO2 nanoparticles on the surface of the Fe3O4 spheres wrapped by graphene oxide (GO) which was obtained by an electrostatic layer-by-layer method. This as-prepared catalyst reflected good ferromagnetism and superior stability which makes it convenient to be separated and recycled. Due to the synergic effects between the different components composed the catalyst, swift reduction of Fe(3+) can be achieved to regenerate Fe(2+). Fe3O4@rGO@TiO2 exhibited enhancing catalytic activity for the degradation of azo-dyes compared with Fe3O4, Fe3O4@SiO2@TiO2 or SiO2@rGO@TiO2, further conforming the rapid redox reaction between Fe(2+) and Fe(3+). All these merits indicate that the composite catalyst possesses great potential for visible-light driven destruction of organic compounds.

  14. A facile one-pot hydrothermal synthesis of β-MnO2 nanopincers and their catalytic degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Cheng, Gao; Yu, Lin; Lin, Ting; Yang, Runnong; Sun, Ming; Lan, Bang; Yang, Lili; Deng, Fangze

    2014-09-01

    Branched β-MnO2 bipods with novel nanopincer morphology were prepared by a facile one-pot hydrothermal method via a redox reaction between NaClO3 and MnSO4 in sulfuric acid solution without using any surfactants or templates. The products were characterized in detail by various techniques including X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, surface area analyzer, field emission scanning electron microscopy and transmission electron microscopy. Results show that the obtained β-MnO2 nanopincers consist of two sharp nanorods with a diameter of 100-200 nm and a length of 1-2 μm. The concentration of H2SO4 solution plays an important role in controlling the crystal phase and morphology of the final product. A possible formation mechanism for the β-MnO2 nanopincers was proposed. Moreover, these β-MnO2 nanostructures exhibited better catalytic performance than the commercial MnO2 particles to decompose methyl blue (MB) in the presence of H2O2.

  15. Growth of Fe2O3/SnO2 nanobelt arrays on iron foil for efficient photocatalytic degradation of methylene blue

    NASA Astrophysics Data System (ADS)

    Lei, Rui; Ni, Hongwei; Chen, Rongsheng; Zhang, Bowei; Zhan, Weiting; Li, Yang

    2017-04-01

    Tin(IV) oxide has been intensively employed in optoelectronic devices due to its excellent electrical and optical properties. But the high recombination rates of the photogenerated electron-hole pairs of SnO2 nanomaterials often results in low photocatalytic efficiency. Herein, we proposed a facile route to prepare a novel Fe2O3/SnO2 heterojunction structure. The nanobelt arrays grown on iron foil naturally form a Schottky-type contact and provide a direct pathway for the photogenerated excitons. Hence, the Fe2O3/SnO2 nanobelt arrays exhibit much improved photocatalytic performance with the degradation rate constant on the Fe2O3/SnO2 film of approximately 12 times to that of α-Fe2O3 nanobelt arrays.

  16. Photocatalytic degradation of methylene blue dye and magneto-optical studies of magnetically recyclable spinel NixMn1-xFe2O4 (x = 0.0-1.0) nanoparticles

    NASA Astrophysics Data System (ADS)

    Mathubala, G.; Manikandan, A.; Arul Antony, S.; Ramar, P.

    2016-06-01

    Nickel doped spinel manganese ferrite (NixMn1-xFe2O4: x = 0.0-1.0) nanoparticles were prepared successfully by a superficial microwave irradiation technique using urea as the fuel. Powder X-ray diffraction (XRD) analysis was recognized the configuration of single phase spinel structure of NixMn1-xFe2O4. Debye Sherrer's formula was used to calculate the average crystallite size of the samples, which were found in the range of 15-20 nm. High resolution scanning electron microscopy (HR-SEM) was used to analyze the surface morphology of the samples, which showed the particle like-morphology with smaller agglomeration, and it was also confirmed by high resolution transmission electron microscopy (HR-TEM). Energy dispersive X-ray (EDX) analysis confirmed the elemental composition, which also evidence for the formation of single pure phase. Microwave heating method produced well crystalline nature of the products, which was confirmed by selected area electron diffraction (SAED) analysis. UV-Visible diffuse reflectance spectra (DRS) were used to calculate the energy band gap and the observed values are increased slightly from 2.05 eV to 2.44 eV with increasing the Ni-dapant. Magnetic characterization of the samples were analyzed by room temperature vibrating sample magnetometer (VSM) technique and the observed magnetization (Ms) values are decreased with increasing Ni content, due to the different magnetic moments of Mn2+ and Ni2+ cations. Photocatalytic degradation (PCD) of methylene blue dye was carried out by self designed photo-catalytic reactor. It was observed that PCD efficiency is increased with increase in concentration of Ni and the sample Ni0.6Mn0.4Fe2O4 shows better photocatalytic activity (96.73%) than other samples.

  17. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles

    PubMed Central

    Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

    2015-01-01

    Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R2 values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R2 values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents. PMID:26843977

  18. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles.

    PubMed

    Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

    2016-01-01

    Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R (2) values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R (2) values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents.

  19. Cadmium oxide nanoparticles grown in situ on reduced graphene oxide for enhanced photocatalytic degradation of methylene blue dye under ultraviolet irradiation.

    PubMed

    Kumar, Sumeet; Ojha, Animesh K; Walkenfort, Bernd

    2016-06-01

    Cadmium oxide (CdO) nanoparticles (NPs), reduced graphene oxide (rGO) and rGO-CdO nanocomposites have been synthesized using one step hydrothermal method. The structural and optical properties of CdO NPs, rGO, and rGO-CdO nanocomposites were investigated by X-ray diffraction (XRD), energy dispersive X-ray (EDX), high resolution transmission electron microscopy (HR-TEM), Raman spectroscopy (RS), ultraviolet-visible spectroscopy (UV-Vis.) and photoluminescence (PL) spectroscopy techniques. The rGO has a sharp 2D peak compared to GO. The sharp nature of 2D band may be due to the larger contribution from single layer sheet. The photocatalytic activity of the synthesized samples has been investigated under UV irradiation. The results of photocatalytic measurements revealed that ~80% of MB dye is degraded by adding the rGO-CdO nanocomposites as photocatalysts into the dye solution. The decrease in the intensity of emission peaks indicates that the photogenerated charge carriers have been transferred from CdO NPs to rGO sheets, which causes to increase the density of O2(-) and OH radicals in the dye solution. The CdO nanoparticles gown on the rGO sheets showed enhanced ferromagnetism (FM) at room temperature, which may be attributed to the short range magnetic interaction of magnetic moments of CdO NPs and spin units present on the rGO sheets.

  20. Methylene blue for distributive shock: a potential new use of an old antidote.

    PubMed

    Jang, David H; Nelson, Lewis S; Hoffman, Robert S

    2013-09-01

    Methylene blue is used primarily in the treatment of patients with methemoglobinemia. Most recently, methylene blue has been used as a treatment for refractory distributive shock from a variety of causes such as sepsis and anaphylaxis. Many studies suggest that the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway plays a significant role in the pathophysiology of distributive shock. There are some experimental and clinical experiences with the use of methylene blue as a selective inhibitor of the NO-cGMP pathway. Methylene blue may play a role in the treatment of distributive shock when standard treatment fails.

  1. Removal of methylene blue from dye effluent using ageratum conyzoide leaf powder (ACLP)

    NASA Astrophysics Data System (ADS)

    Ezechi, Ezerie Henry; Kutty, Shamsul Rahman bin Mohamed; Malakahmad, Amirhossein; Isa, Mohamed Hasnain; Aminu, Nasiru; Salihi, Ibrahim Umar

    2015-07-01

    Methylene blue (MB), a common environmental pollutant discharged from dye effluents were removed from synthetic effluents in this study using ageratum conyzoide leaf powder. Effects of operating parameters such as pH, initial Methylene blue concentration, adsorbent weight and contact time were examined on methylene blue removal whereas stirring speed was constant at 100 rpm. Results show that low pH (3-4) had more Methylene blue removal than high pH. Methylene blue removal decreased when initial concentration was increased but increased when adsorbent weight was increased. Removal of Methylene blue by Ageratum conyzoide leaf powder was rapid and significantly above 80% in all initial concentrations examined. At optimum conditions of pH 3, 20 minutes contact time and adsorbent weight of 60 mg for Methylene blue initial concentration of 20 mg/L, 40 mg/L and 60 mg/L, Methylene blue removal of 84.7%, 83.9% and 81.2% were obtained respectively. Results suggest that Ageratum conyzoide leaf powder could be potential adsorbents for Methylene blue removal from dye effluents.

  2. Photosensitizer methylene blue-semiconductor nanocrystals hybrid system for photodynamic therapy.

    PubMed

    Rakovich, Aliaksandra; Rakovich, Tatsiana; Kelly, Vincent; Lesnyak, Vladimir; Eychmüller, Alexander; Rakovich, Yury P; Donegan, John F

    2010-04-01

    In this work we report on the development of novel hybrid material with enhanced photodynamic properties based on methylene blue and CdTe nanocrystals. Absorption spectroscopy, visible photoluminescence spectroscopy and fluorescence lifetime imaging of this system reveal efficient charge transfer between nanocrystals and the methylene blue dye. Near infra-red photoluminescence measurements provide evidence for an increased efficiency of singlet oxygen production by the methylene blue dye. In vitro studies on the growth of HepG2 and HeLa cancerous cells were also performed, they point towards an improvement in the cell kill efficiency for the methylene blue-semiconductor nanocrystals hybrid system.

  3. In Situ XANES Study of CuO/TiO2 Thin Films During Photodegradation of Methylene Blue

    SciTech Connect

    Hsiung Tungli; Wang, H. Paul; Wei Yuling

    2007-02-02

    Speciation of copper in the CuO/TiO2 thin film (synthesized by the doctor-blade deposition method) during photocatalytic decomposition of methylene blue has been studied by in situ X-ray absorption near-edge structural (XANES) spectroscopy. During the UV/VIS radiation (90 min), in the presence of methylene blue, a decrease of Cu(II) and an increases of Cu(0) and Cu(I) fractions in the CuO/TiO2 thin film are observed by in situ XANES. The r-space Fourier transformation EXAFS (extend X-ray absorption fine structural) spectra also show that the bond distance of Cu-O in the thin film is decreased by 0.03 A during photocatalytic degradation of methylene blue.

  4. Adsorption behavior of methylene blue on carbon nanotubes.

    PubMed

    Yao, Yunjin; Xu, Feifei; Chen, Ming; Xu, Zhongxiao; Zhu, Zhiwen

    2010-05-01

    The effect of temperature on the equilibrium adsorption of methylene blue dye from aqueous solution using carbon nanotubes was investigated. The equilibrium adsorption data were analyzed using two widely applied isotherms: Langmuir and Freundlich. The results revealed that Langmuir isotherm fit the experimental results well. Kinetic analyses were conducted using pseudo-first and second-order models and the intraparticle diffusion model. The regression results showed that the adsorption kinetics were more accurately represented by pseudo-second-order model. The activation energy of system (Ea) was calculated as 18.54 kJ/mol. Standard free energy changes (DeltaG(0)), standard enthalpy change (DeltaH(0)), and standard entropy change (DeltaS(0)) were calculated using adsorption equilibrium constants obtained from the Langmuir isotherm at different temperatures. All DeltaG(0) values were negative; the DeltaH(0) values and DeltaS(0) values of CNTs were 7.29 kJ/mol and 64.6 J/mol K, respectively. Results suggested that the methylene blue adsorption on CNTs was a spontaneous and endothermic process.

  5. Comparison of TiO2 and ZnO nanoparticles for photocatalytic degradation of methylene blue and the correlated inactivation of gram-positive and gram-negative bacteria

    NASA Astrophysics Data System (ADS)

    Barnes, Robert J.; Molina, Rodrigo; Xu, Jianbin; Dobson, Peter J.; Thompson, Ian P.

    2013-02-01

    Titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles are important photocatalysts and as such have been extensively studied for the removal of organic compounds from contaminated air and water and for microbial disinfection. Despite much research on the effect of TiO2 and ZnO nanoparticles on different bacterial species, uncertainties remain about which bacteria are more sensitive to these compounds. Very few studies have directly compared the toxicity of ZnO to TiO2 under both light and dark conditions. In addition, authors investigating the photocatalytic inactivation of TiO2 and ZnO nanoparticles on bacteria have failed to investigate the reactive oxygen species (ROS) generation of the nanoparticles, making it difficult to correlate killing action with the generation of ROS. In this study, three types of metal nanoparticle (ZnO < 50 nm, ZnO < 100 nm and TiO2) have been characterised and ROS production assessed through the degradation of methylene blue (MB). The photocatalytic killing potential of three nanoparticle concentrations (0.01, 0.1 and 1 g/L) was then assessed on four representative bacteria: two gram-positive ( S. aureus and B. subtilis) and two gram-negative ( E. coli and P. aeruginosa). Results showed that out of the three nanoparticles tested, the TiO2 nanoparticles generated more ROS than the ZnO nanoparticles, corresponding to a greater photocatalytic inactivation of three of the four species of bacteria examined. The MB decomposition results correlated well with the bacterial inactivation results with higher TiO2 nanoparticle concentrations leading to greater ROS production and increased loss of cell viability. Although producing less ROS than the TiO2 nanoparticles under ultraviolet light, the ZnO nanoparticles were toxic to two of the bacterial species even under dark conditions. In this study, no correlation between cell wall type and bacterial inactivation was observed for any of the nanoparticles tested although both gram

  6. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Heinz body hemolytic anemia reaction to methylene blue has also been demonstrated in dogs under... cats or dogs. (1)(i) It has been demonstrated that two orally administered urinary antiseptic-antispasmodic preparations that contained methylene blue cause Heinz body hemolytic anemia in cats when...

  7. 21 CFR 500.27 - Methylene blue-containing drugs for use in animals.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...-antispasmodic preparations that contained methylene blue cause Heinz body hemolytic anemia in cats when used... Heinz body hemolytic anemia reaction to methylene blue has also been demonstrated in dogs under... inclusion bodies (Heinz bodies) and associated hemolytic anemia is unclear. (2) The effectiveness of...

  8. Suspected serotonin syndrome in a patient being treated with methylene blue for ifosfamide encephalopathy.

    PubMed

    McDonnell, A M; Rybak, I; Wadleigh, M; Fisher, D C

    2012-12-01

    Methylene blue has been used not only as a diagnostic agent, but also as an agent in the treatment of ifosfamide-induced encephalopathy (IIE) for several years. Recently, several cases of suspected serotonin syndrome have been reported in patients who received methylene blue in combination with serotonin active agents. Rodent models have revealed that methylene blue is a potent, reversible inhibitor of monoamine oxidase A. It is well known that serotonin active drugs, in combination with monoamine oxidase inhibitors can produce profound serotonin syndrome. To date, cases of serotonin syndrome, which resulted from concurrent methylene blue and serotonin active agents, have been published in the anesthesia literature. We report the first known case of serotonin syndrome in a patient receiving methylene blue for IIE.

  9. [Decolorization of methylene blue by bovine spermatozoa and its significance in artificial insemination (author's transly].

    PubMed

    Aalbers, J G

    1976-03-15

    The mechanism of action of methylene blue reduction is discussed with special reference to its relationship to the metabolism of bovine spermatozoa. The results of experimental studies of the effect of metabolic inhibitors on decolorization of methylene blue are reported. Attention is also paid to the effect of the addition of methylene blue to semen on the oxygen uptake of bovine spermatozoa. Methods used to determine the decolorization time of methylene blue in artificial insemination are reviewed. One of these methods is described in greater detail. The results of a number of experiments is concerned with the effect of environmental factors on the decolorization times of suspensions of spermatozoa are reported. Finally, the relationship between the decolorization time of methylene blue and a number of other semen characteristics as well as usefulness of this method in artificial insemination are discussed.

  10. Singlet oxygen luminescence detecting in presence of hybrid associates of colloidal Ag2S quantum dots with methylene blue molecules

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, O. V.; Kondratenko, T. S.; Smirnov, M. S.; Perepelitsa, A. S.; Grevtseva, I. G.; Vinokur, Y. A.; Aslanov, S. V.; Matsukovich, A. S.

    2016-12-01

    In our work we demonstrate some spectroscopic investigation of colloidal Ag2S QDs associates with methylene blue. The photosensitizing of singlet oxygen by associates of colloidal Ag2S QDs with methylene blue was found.

  11. Study of Methylene Blue adsorption on keratin nanofibrous membranes.

    PubMed

    Aluigi, A; Rombaldoni, F; Tonetti, C; Jannoke, L

    2014-03-15

    In this work, keratin nanofibrous membranes (mean diameter of about 220nm) were prepared by electrospinning and tested as adsorbents for Methylene Blue through batch adsorption tests. The adsorption capacity of the membranes was evaluated as a function of initial dye concentration, pH, adsorbent dosage, time and temperature. The adsorption capacity increased with increasing the initial dye concentration and pH, while it decreased with increasing the adsorbent dosage and temperature, indicating an exothermic process. The adsorption results indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich and Temkin isotherm models. A mean free energy evaluated through the Dubinin-Radushkevich model of about 16kJmol(-1), indicated a chemisorption process which occurred by ion exchange. The kinetic data were found to fit the pseudo-second-order model better than the pseudo-first-order model. The obtained results suggest that keratin nanofibrous membranes could be promising candidates as dye adsorption filters.

  12. Adsorption studies of methylene blue dye on tunisian activated lignin

    NASA Astrophysics Data System (ADS)

    Kriaa, A.; Hamdi, N.; Srasra, E.

    2011-02-01

    Activated carbon prepared from natural lignin, providing from a geological deposit, was used as the adsorbent for the removal of methylene blue (MB) dye from aqueous solutions. Batch adsorption studies were conducted to evaluate various experimental parameters like pH and contact time for the removal of this dye. Effective pH for MB removal was 11. Kinetic study showed that the adsorption of dye was gradual process. Quasi equilibrium reached in 4 h. Pseudo-first-order, pseudo-second-order were used to fit the experimental data. Pseudo-second-order rate equation was able to provide realistic description of adsorption kinetics. The experimental isotherms data were also modelled by the Langmuir and Freundlich equation of adsorption. Equilibrium data fitted well with the Langmuir model with maximum monolayer adsorption capacity of 147 mg/g. Activated lignin was shown to be a promising material for adsorption of MB from aqueous solutions.

  13. Nanosized ZSM-5 will improve photodynamic therapy using Methylene blue.

    PubMed

    Kariminezhad, H; Habibi, M; Mirzababayi, N

    2015-07-01

    Nowadays, nanotechnology is growing to improve Photodynamic Therapy and reduce its side effects. In this research, the synthesized co-polymeric Zeolite Secony Mobile-5 (ZSM-5) was employed to modify Methylene Blue (MB) for these reasons. UV-Visible, FTIR, XRD analysis and SEM images were used to investigate obtained nanostructure. The crystal size for these nanostructures were determined 75 nm and maximum adsorption capacity of MB in the nanostructure was estimated 111 (mg g(-1)). Also, the role of Polyethylene Glycol (PEG) was studied as a capable non-toxic polymeric coating to overcome biological barriers. Moreover, potential of singlet oxygen production of the synthesized nanostructure was compared with MB and ZSM-5 nanoparticles control samples. Synthesized nanodrugs show impressive light induced singlet oxygen production efficiency.

  14. Methylene blue adsorption on a DMPA lipid langmuir monolayer.

    PubMed

    Giner Casares, Juan José; Camacho, Luis; Martín-Romero, Maria Teresa; López Cascales, José Javier

    2010-07-12

    Adsorption of methylene blue (MB) onto a dimyristoylphosphatidic acid (DMPA) Langmuir air/water monolayer is studied by molecular dynamics (MD) simulations, UV reflection spectroscopy and surface potential measurements. The free-energy profile associated with MB transfer from water to the lipid monolayer shows two minima of -66 and -60 kJ mol(-1) for its solid and gas phase, respectively, corresponding to a spontaneous thermodynamic process. From the position of the free-energy minima, it is possible to predict the precise location of MB in the interior of the DMPA monolayer. Thus, MB is accommodated in the phosphoryl or carbonyl region of the DMPA Langmuir air/water interface, depending on the isomorphic state (solid or gas phase, respectively). Reorientation of MB, measured from the bulk solution to the interior of the lipid monolayer, passes from a random orientation in bulk solution to an orientation parallel to the surface of the lipid monolayer when MB is absorbed.

  15. In vivo molecular contrast OCT imaging of methylene blue.

    PubMed

    Kim, Wihan; Applegate, Brian E

    2015-04-01

    An 830-nm spectral-domain optical coherence tomography (OCT) system with an integrated 663-nm diode pump laser has been developed to enable molecular contrast OCT imaging of methylene blue (MB), a common vital dye used clinically. The introduction of the 663-nm diode laser, which acts as the pump in this implementation of pump-probe OCT (PPOCT), represents a minor modification to an otherwise typical OCT system. A newly developed background subtraction technique completely removes all background from intensity noise at the pump modulation frequency, simplifying the interpretation of PPOCT images. These developments have enabled the first in vivo imaging of MB with PPOCT. Volumetric images of a zebrafish, stained by submersion in a 0.01% (w/v) solution of MB for 6 h, show accumulation of MB in the mesonephros, the primordial filtration organ.

  16. Treatment of dilute methylene blue-containing wastewater by coupling sawdust adsorption and electrochemical regeneration.

    PubMed

    Bouaziz, I; Chiron, C; Abdelhedi, R; Savall, A; Groenen Serrano, K

    2014-01-01

    In the present work, the coupling of adsorption and electrochemical oxidation on a boron-doped diamond (BDD) electrode to treat solutions containing dyes is studied. This coupling may be convenient for the treatment of diluted pollutant that is limited by the low rate of electrooxidation due to mass-transfer limitation. A pre-concentration step by adsorption could minimize the design of the electrochemical reactor. The adsorbent chosen was mixed with softwood sawdust, and methylene blue was chosen as the model dye molecule. Isotherms of adsorption and kinetics were investigated as well as the effects of current density and regeneration time. The BDD electrochemical oxidation of methylene blue adsorbed onto sawdust led simultaneously to its degradation and sawdust regeneration for the next adsorption. It was observed that multiple adsorption and electrochemical regeneration cycles led to an enhancement of adsorption capacity of the sawdust. This study demonstrated that adsorption–electrochemical degradation coupling offers a promising approach for the efficient elimination of organic dyes from wastewater.

  17. Effectiveness of purified methylene blue in an experimental model of Mycobacterium ulcerans infection.

    PubMed

    Tian, Roger B D; Asmar, Shady; Napez, Claude; Lépidi, Hubert; Drancourt, Michel

    2017-03-01

    Mycobacterium ulcerans is responsible for Buruli ulcer, characterised by extensive, disabling ulcers. Standard treatment combining rifampicin and streptomycin exposes patients to toxicity and daily painful injections. In this study, the in vitro susceptibilities of 3 M. ulcerans strains, 1 Mycobacterium marinum strain and 18 strains representative of eleven other Mycobacterium species and subspecies to methylene blue were determined. Whilst growth of M. ulcerans was inhibited by 0.0125 g/L methylene blue, growth of all other tested strains was not inhibited by 1 g/L methylene blue. The effectiveness of methylene blue in a murine model of M. ulcerans infection was then tested. Topical treatment by brushing a methylene blue solution on the skin lesion, systemic treatment by intraperitoneal injection of methylene blue, and a combined treatment (topical and systemic) were tested. The three treatment groups exhibited a significantly lower clinical score compared with the non-treated control group (P <0.05). Moreover, subcutaneous nodules were significantly smaller in the systemic treatment group (excluding males) (3 ± 0.7 mm) compared with the other groups (P <0.05). The M. ulcerans insertion sequence IS2404 and the KR-B gene were detected in all challenged mice, but not in negative controls. The density of M. ulcerans (mycobacteria/cell) was significantly lower in the combined treatment group compared with the other groups. These data provide evidence for the effectiveness of purified methylene blue against the initial stage of Buruli ulcer.

  18. Desorption behavior of methylene blue on pyromellitic dianhydride modified biosorbent by a novel eluent: acid TiO2 hydrosol.

    PubMed

    Yu, Jun-Xia; Chi, Ru-An; Su, Xiu-Zhu; He, Zheng-Yan; Qi, Ya-Feng; Zhang, Yue-Fei

    2010-05-15

    In this study, waste beer yeast powder was modified by pyromellitic dianhydride to improve its adsorption capacities for cationic dye: methylene blue (MB). According to the Langmuir equation, the maximum uptake capacities (q(m)) of the modified biomass for MB was 830.8 mg g(-1), which was about five times than that obtained on the unmodified biomass. Adsorption mechanism was investigated by FTIR. Desorption kinetics of methylene blue in six solvents: HCl (0.1 mol L(-1)), ethanol, mixtures of HCl (0.1 mol L(-1)) and ethanol with different volume ratio and a self-clean eluent: acid TiO(2) were studied in details. Results showed that desorption kinetics curve fit the two-step kinetic model, and methylene blue release process was distinctly divided into two steps: rapid and slow desorption steps. 52.2% of the methylene blue could be desorbed into TiO(2) hydrosol after 30 h desorption at the first desorption cycle, and the desorbed dye in TiO(2) hydrosol could be degrade completely under sunlight irradiation. After three desorption-photodegradation cycles, 80.0% of the absorbed dyes could be desorbed from the surface of the modified biomass. Although there was much work to do, the self-clean eluent: TiO(2) hydrosol had great potential in practical use.

  19. Methylene blue prevents retinal damage in an experimental model of ischemic proliferative retinopathy.

    PubMed

    Rey-Funes, Manuel; Larrayoz, Ignacio M; Fernández, Juan C; Contartese, Daniela S; Rolón, Federico; Inserra, Pablo I F; Martínez-Murillo, Ricardo; López-Costa, Juan J; Dorfman, Verónica B; Martínez, Alfredo; Loidl, César F

    2016-06-01

    Perinatal asphyxia induces retinal lesions, generating ischemic proliferative retinopathy, which may result in blindness. Previously, we showed that the nitrergic system was involved in the physiopathology of perinatal asphyxia. Here we analyze the application of methylene blue, a well-known soluble guanylate cyclase inhibitor, as a therapeutic strategy to prevent retinopathy. Male rats (n = 28 per group) were treated in different ways: 1) control group comprised born-to-term animals; 2) methylene blue group comprised animals born from pregnant rats treated with methylene blue (2 mg/kg) 30 and 5 min before delivery; 3) perinatal asphyxia (PA) group comprised rats exposed to perinatal asphyxia (20 min at 37°C); and 4) methylene blue-PA group comprised animals born from pregnant rats treated with methylene blue (2 mg/kg) 30 and 5 min before delivery, and then the pups were subjected to PA as above. For molecular studies, mRNA was obtained at different times after asphyxia, and tissue was collected at 30 days for morphological and biochemical analysis. Perinatal asphyxia produced significant gliosis, angiogenesis, and thickening of the inner retina. Methylene blue treatment reduced these parameters. Perinatal asphyxia resulted in a significant elevation of the nitrergic system as shown by NO synthase (NOS) activity assays, Western blotting, and (immuno)histochemistry for the neuronal isoform of NOS and NADPH-diaphorase activity. All these parameters were also normalized by the treatment. In addition, methylene blue induced the upregulation of the anti-angiogenic peptide, pigment epithelium-derived factor. Application of methylene blue reduced morphological and biochemical parameters of retinopathy. This finding suggests the use of methylene blue as a new treatment to prevent or decrease retinal damage in the context of ischemic proliferative retinopathy.

  20. Methylene Blue for Vasoplegia When on Cardiopulmonary Bypass During Double-Lung Transplantation.

    PubMed

    Carley, Michelle; Schaff, Jacob; Lai, Terrance; Poppers, Jeremy

    2015-10-15

    Vasoplegia syndrome, characterized by hypotension refractory to fluid resuscitation or high-dose vasopressors, low systemic vascular resistance, and normal-to-increased cardiac index, is associated with increased morbidity and mortality after cardiothoracic surgery. Methylene blue inhibits inducible nitric oxide synthase and guanylyl cyclase, and has been used to treat vasoplegia during cardiopulmonary bypass. However, because methylene blue is associated with increased pulmonary vascular resistance, its use in patients undergoing lung transplantion has been limited. Herein, we report the use of methylene blue to treat refractory vasoplegia during cardiopulmonary bypass in a patient undergoing double-lung transplantation.

  1. Complexing Methylene Blue with Phosphorus Dendrimers to Increase Photodynamic Activity.

    PubMed

    Dabrzalska, Monika; Janaszewska, Anna; Zablocka, Maria; Mignani, Serge; Majoral, Jean Pierre; Klajnert-Maculewicz, Barbara

    2017-02-23

    The efficiency of photodynamic therapy is limited mainly due to low selectivity, unfavorable biodistribution of photosensitizers, and long-lasting skin sensitivity to light. However, drug delivery systems based on nanoparticles may overcome the limitations mentioned above. Among others, dendrimers are particularly attractive as carriers, because of their globular architecture and high loading capacity. The goal of the study was to check whether an anionic phosphorus dendrimer is suitable as a carrier of a photosensitizer-methylene blue (MB). As a biological model, basal cell carcinoma cell lines were used. We checked the influence of the MB complexation on its singlet oxygen production ability using a commercial fluorescence probe. Next, cellular uptake, phototoxicity, reactive oxygen species (ROS) generation, and cell death were investigated. The MB-anionic dendrimer complex (MB-1an) was found to generate less singlet oxygen; however, the complex showed higher cellular uptake and phototoxicity against basal cell carcinoma cell lines, which was accompanied with enhanced ROS production. Owing to the obtained results, we conclude that the photodynamic activity of MB complexed with an anionic dendrimer is higher than free MB against basal cell carcinoma cell lines.

  2. Adsorption of methylene blue onto sonicated sepiolite from aqueous solutions.

    PubMed

    Küncek, Ilknur; Sener, Savaş

    2010-01-01

    The aim of the present study is to enhance the methylene blue (MB) adsorption of sepiolite by ultrasonic treatment. The natural sepiolite was pretreated by sonication to improve the surface characteristics and enhance the dye uptake capacity. Sonication process resulted in a significant increase in the specific surface area (SSA) of sepiolite. The FTIR spectrum of the sonicated sepiolite indicates that the tetrahedral sheet is probably distorted after sonication process. The effect of various parameters such as sonication, pH, initial dye concentration and temperature on dye adsorption has been investigated. The adsorbed amount of MB on sepiolite increased after sonication as well as with increasing pH and temperature. The experimental data were evaluated by applying the pseudo-first- and second-order, and the intraparticle diffusion adsorption kinetic models. Adsorption process of MB onto sepiolite followed the pseudo-second-order rate expression. The experimental data were analyzed by Langmuir and Freundlich isotherms, and found that the isotherm data were reasonably well correlated by Langmuir isotherm. Maximum monolayer adsorption capacity of sepiolite for MB increased from 79.37 to 128.21 mg/g after the sonication. Various thermodynamic parameters, such as Delta G(0), Delta H(0) and DeltaS(0) were calculated. The thermodynamics of MB/sepiolite system indicated spontaneous and endothermic nature of the process. Adsorption measurements showed that the process was very fast and physical in nature.

  3. Removal of methylene blue by lava adsorption and catalysis oxidation.

    PubMed

    Ma, Jianfeng; Zhang, Jinbao; Li, Dinglong

    2010-03-01

    Adsorption has been found to be effective for the removal of dyes from effluent; however, the contaminant will cause secondary pollution if it is not properly treated. In this paper, the ability of lava as a low-cost adsorbent and catalyst for the removal of a commercial dye, Methylene Blue (MB), from aqueous solution has been investigated under various experimental conditions. It was found that lava had a high efficiency (more than 98%) for MB removal by adsorption. The adsorption equilibrium data can be fitted well by the Langmuir adsorption isotherm model. The adsorption kinetics was shown to be pseudo-second-order. After adsorption the contaminant could be catalysis oxidized by lava with the aids of H2O2 and ultrasound. The result showed that 95% of the MB could be decomposed in 100 min with the aid of ultrasound at 85 W/cm2. Overall, this study demonstrates lava as a promising material for wastewater treatment to remove and decompose dyes in a single treatment step.

  4. Neuroprotective Actions of Methylene Blue and Its Derivatives

    PubMed Central

    Poteet, Ethan; Winters, Ali; Yan, Liang-Jun; Shufelt, Kyle; Green, Kayla N.; Simpkins, James W.; Wen, Yi; Yang, Shao-Hua

    2012-01-01

    Methylene blue (MB), the first lead chemical structure of phenothiazine and other derivatives, is commonly used in diagnostic procedures and as a treatment for methemoglobinemia. We have previously demonstrated that MB could function as an alternative mitochondrial electron transfer carrier, enhance cellular oxygen consumption, and provide protection in vitro and in rodent models of Parkinson’s disease and stroke. In the present study, we investigated the structure-activity relationships of MB in vitro using MB and six structurally related compounds. MB reduces mitochondrial superoxide production via alternative electron transfer that bypasses mitochondrial complexes I-III. MB mitigates reactive free radical production and provides neuroprotection in HT-22 cells against glutamate, IAA and rotenone toxicity. Distinctly, MB provides no protection against direct oxidative stress induced by glucose oxidase. Substitution of a side chain at MB’s 10-nitrogen rendered a 1000-fold reduction of the protective potency against glutamate neurototoxicity. Compounds without side chains at positions 3 and 7, chlorophenothiazine and phenothiazine, have distinct redox potentials compared to MB and are incapable of enhancing mitochondrial electron transfer, while obtaining direct antioxidant actions against glutamate, IAA, and rotenone insults. Chlorophenothiazine exhibited direct antioxidant actions in mitochondria lysate assay compared to MB, which required reduction by NADH and mitochondria. MB increased complex IV expression and activity, while 2-chlorphenothiazine had no effect. Our study indicated that MB could attenuate superoxide production by functioning as an alternative mitochondrial electron transfer carrier and as a regenerable anti-oxidant in mitochondria. PMID:23118969

  5. Role of Methylene Blue in Trauma Neuroprotection and Neuropsychiatric Diseases.

    PubMed

    Batista-Filho, Mário Márcio Vasconcelos; Kandratavicius, Ludmyla; Nunes, Emerson Arcoverde; Tumas, Vitor; Colli, Benedicto O; Hallak, Jaime E C; Maia-de-Oliveira, João Paulo; Evora, Paulo Roberto B

    2016-01-01

    The prevalence of central nervous system trauma, neurodegenerative and psychiatric diseases has significantly increased in recent years. Most of these diseases show multifactorial causes and several progression mechanisms. The search for a medication which positively interferes in these mechanisms and thereby changes the course of these diseases is of great scientific interest. The aim of the present review is to assess current literature on the possible role of methylene blue (MB) in the central nervous system due to the increasing number of citations in spite of the few articles available on the subject which suggest growing interest in the protective effects of MB on the central nervous system. Searches were performed on PubMed and Thomson Reuters Web of Knowledge. Therefore, we provide an overview of existing articles concerning: 1) MB actions; 2) MB neuroprotection and cardiac arrest; 3) MB neuroprotection and degenerative brain diseases; 4) MB neuroprotection and psychiatric diseases. PubMed was chosen because it holds the highest number of articles on the subject, Thomson Reuters was chosen due to its functionality which evaluates citations through analytic graphs. We conclude that MB has a beneficial effect and acts through many mechanisms and pathways of the central nervous system, being a potential alternative for the treatment of many neurodegenerative and psychiatric diseases.

  6. Methylene blue alleviates nuclear and mitochondrial abnormalities in progeria.

    PubMed

    Xiong, Zheng-Mei; Choi, Ji Young; Wang, Kun; Zhang, Haoyue; Tariq, Zeshan; Wu, Di; Ko, Eunae; LaDana, Christina; Sesaki, Hiromi; Cao, Kan

    2016-04-01

    Hutchinson-Gilford progeria syndrome (HGPS), a fatal premature aging disease, is caused by a single-nucleotide mutation in the LMNA gene. Previous reports have focused on nuclear phenotypes in HGPS cells, yet the potential contribution of the mitochondria, a key player in normal aging, remains unclear. Using high-resolution microscopy analysis, we demonstrated a significantly increased fraction of swollen and fragmented mitochondria and a marked reduction in mitochondrial mobility in HGPS fibroblast cells. Notably, the expression of PGC-1α, a central regulator of mitochondrial biogenesis, was inhibited by progerin. To rescue mitochondrial defects, we treated HGPS cells with a mitochondrial-targeting antioxidant methylene blue (MB). Our analysis indicated that MB treatment not only alleviated the mitochondrial defects but also rescued the hallmark nuclear abnormalities in HGPS cells. Additional analysis suggested that MB treatment released progerin from the nuclear membrane, rescued perinuclear heterochromatin loss and corrected misregulated gene expression in HGPS cells. Together, these results demonstrate a role of mitochondrial dysfunction in developing the premature aging phenotypes in HGPS cells and suggest MB as a promising therapeutic approach for HGPS.

  7. Adsorptive decolorization of methylene blue by crosslinked porous starch.

    PubMed

    Guo, Lei; Li, Guiying; Liu, Junshen; Meng, Yanfeng; Tang, Yanfeng

    2013-04-02

    Crosslinked porous starch (CPS) was prepared by two steps. Native starch was crosslinked with epichlorohydrin and then CPS was prepared by hydrolyzing the crosslinked starch with α-amylase. As a biodegradable and safe adsorbent, CPS was used to remove methylene blue (MB) from the aqueous solution based on its characterizations, including surface area, pore volume and scanning electron microscopy (SEM). The results indicate that the adsorption capacity of CPS is much higher than native starch and relatively higher than porous starch. The effects of the initial concentration of MB, the time and temperature on the adsorption capacity were investigated. The pseudo-first-order kinetic model provides a better correlation of the experimental data in comparison with the pseudo-second-order model. The equilibrium adsorption data are well described by the Langmuir isotherm model with a maximum adsorption capacity of 9.46mg g(-1). The adsorption of MB on CPS is endothermic and spontaneous in nature. The thermodynamics data are in good agreement with physical adsorption mechanism.

  8. Methylene blue modulates functional connectivity in the human brain.

    PubMed

    Rodriguez, Pavel; Singh, Amar P; Malloy, Kristen E; Zhou, Wei; Barrett, Douglas W; Franklin, Crystal G; Altmeyer, Wilson B; Gutierrez, Juan E; Li, Jinqi; Heyl, Betty L; Lancaster, Jack L; Gonzalez-Lima, F; Duong, Timothy Q

    2016-03-10

    Methylene blue USP (MB) is a FDA-grandfathered drug used in clinics to treat methemoglobinemia, carbon monoxide poisoning and cyanide poisoning that has been shown to increase fMRI evoked blood oxygenation level dependent (BOLD) response in rodents. Low dose MB also has memory enhancing effect in rodents and humans. However, the neural correlates of the effects of MB in the human brain are unknown. We tested the hypothesis that a single low oral dose of MB modulates the functional connectivity of neural networks in healthy adults. Task-based and task-free fMRI were performed before and one hour after MB or placebo administration utilizing a randomized, double-blinded, placebo-controlled design. MB administration was associated with a reduction in cerebral blood flow in a task-related network during a visuomotor task, and with stronger resting-state functional connectivity in multiple regions linking perception and memory functions. These findings demonstrate for the first time that low-dose MB can modulate task-related and resting-state neural networks in the human brain. These neuroimaging findings support further investigations in healthy and disease populations.

  9. Photoacoustic lifetime imaging of dissolved oxygen using methylene blue

    NASA Astrophysics Data System (ADS)

    Ashkenazi, Shai

    2010-07-01

    Measuring distribution of dissolved oxygen in biological tissue is of prime interest for cancer diagnosis, prognosis, and therapy optimization. Tumor hypoxia indicates poor prognosis and resistance to radiotherapy. Despite its major clinical significance, no current imaging modality provides direct imaging of tissue oxygen. We present preliminary results demonstrating the potential of photoacoustic lifetime imaging (PALI) for noninvasive, 3-D imaging of tissue oxygen. The technique is based on photoacoustic probing of the excited state lifetime of methylene blue (MB) dye. MB is an FDA-approved water soluble dye with a peak absorption at 660 nm. A double pulse laser system (pump probe) is used to excite the dye and probe its transient absorption by detecting photoacoustic emission. The relaxation rate of MB depends linearly on oxygen concentration. Our measurements show high photoacoustic signal contrast at a probe wavelength of 810 nm, where the excited state absorption is more than four times higher than the ground state absorption. Imaging of a simple phantom is demonstrated. We conclude by discussing possible implementations of the technique in clinical settings and combining it with photodynamic therapy (PDT) for real-time therapy monitoring.

  10. Fast and considerable adsorption of methylene blue dye onto graphene oxide.

    PubMed

    Zhang, Wenjie; Zhou, Chunjiao; Zhou, Weichang; Lei, Aihua; Zhang, Qinglin; Wan, Qiang; Zou, Bingsuo

    2011-07-01

    The quite efficient adsorption of methylene blue dye from an aqueous solution by graphene oxide was studied. The favorable electrostatic attraction is the main interaction between methylene blue and graphene oxide. As graphene oxide has the special nanostructural properties and negatively charged surface, the positively charged methylene blue molecules can be easily adsorbed on it. In the aqueous solution of methylene blue at 293 K, the adsorption data could be fitted by the Langmuir equation with a maximum adsorption amount of 1.939 mg/mg and a Langmuir adsorption equilibrium constant of 18.486 mL/mg. The adsorption amount increased with the increase of the solution pH (3-11), was not affected significantly by KCl under the examined condition and the adsorption process was exothermic in nature. The fast and considerable adsorption of graphene oxide could be regarded as a potential adsorbent for cationic dye removal in wastewater treatment process.

  11. Adsorption of methylene blue onto bamboo-based activated carbon: kinetics and equilibrium studies.

    PubMed

    Hameed, B H; Din, A T M; Ahmad, A L

    2007-03-22

    Bamboo, an abundant and inexpensive natural resource in Malaysia was used to prepare activated carbon by physiochemical activation with potassium hydroxide (KOH) and carbon dioxide (CO(2)) as the activating agents at 850 degrees C for 2h. The adsorption equilibrium and kinetics of methylene blue dye on such carbon were then examined at 30 degrees C. Adsorption isotherm of the methylene blue (MB) on the activated carbon was determined and correlated with common isotherm equations. The equilibrium data for methylene blue adsorption well fitted to the Langmuir equation, with maximum monolayer adsorption capacity of 454.2mg/g. Two simplified kinetic models including pseudo-first-order and pseudo-second-order equation were selected to follow the adsorption processes. The adsorption of methylene blue could be best described by the pseudo-second-order equation. The kinetic parameters of this best-fit model were calculated and discussed.

  12. Removal of methylene blue from wastewater using fly ash as an adsorbent by hydrocyclone.

    PubMed

    Rastogi, K; Sahu, J N; Meikap, B C; Biswas, M N

    2008-10-30

    The excessive release of color into the environment is a major concern worldwide. Adsorption process is among the most effective techniques for color removal from wastewater and fly ash has been widely used as an adsorbent. Therefore, this study was carried out to understand the adsorption behavior of methylene blue from aqueous systems onto fly ash using the continuous mode. Continuous mode sorption experiments were carried out to remove methylene blue from its aqueous solutions in hydrocyclone equipment. The experiments were performed at constant temperature and dimensions of hydrocyclone with variation of flows through the equipment, concentrations of methylene blue solutions and fly ash concentration, respectively. A maximum removal of 58.24% was observed at adsorbent dosage of 900 mg/l at pH 6.75 for an initial methylene blue concentration of 65 mg/l.

  13. Effect of lipiodol and methylene blue on the thoracoscopic preoperative positioning.

    PubMed

    Zhang, Chuan-Yu; Yu, Hua-Long; Liu, Shi-He; Jiang, Gang; Wang, Yong-Jie

    2015-01-01

    The aim of this study was to compare and analyze the site-specific accuracy of mixture of lipiodol and methylene blue (MLM) (0.6 ml, 1:5) and pure methylene blue (0.5 ml) on the rabbit lungs. In this study, CT-guided percutaneous injection of MLM and methylene blue. Compare the staining degree by biopsy of lung tissue. Use 4 points system to evaluate the site-specific accuracy at 6h and 24 h after injection. For MLM, evaluate its radiopacity by radiation. When evaluate the positioning, 2 points mean acceptable, 3 points mean excellent. The results indicated that the staining range of MLM is obvious less than that of methylene blue (0.6 vs. 1.0 cm, P<0.01), but the staining capacity of MLM is higher than that of methylene blue (2.8 vs. 2.2, P = 0.01). About the staining abilities which are evaluated as excellent, MLM group accounts for 81%, methylene blue group accounts for 38% (P = 0.011). About the radiopacity which are evaluated as acceptable or excellent, MLM group accounts for 62%. With good direct vision, the suitable positioning rate of MLM can be 100%, which is better than that of methylene blue. In conclusion, percutaneous injection of MLM can be used to lung positioning. The result shows that use MLM is better than only using methylene blue. But it is necessary to do the investigation in human beings in order to confirm the feasibility of its clinical application.

  14. Improvement of the transmittance of methylene-blue-sensitized dichromated gelatin

    NASA Astrophysics Data System (ADS)

    Namba, Shinji; Kurokawa, Kazumasa; Fujita, Tatsuya; Mizuno, Toru; Kubota, Toshihiro

    1992-05-01

    The monomer state methylene blue (MB) dye plays a major role as a sensitizer in methylene blue sensitized dichromated gelatin (MBDCG). The dimer state of the MB can be reduced significantly by controlling the concentration of the MB, the chromium and the water in the gelatin. The authors achieved over 80% transmittance of the MBDCG plate for red light without sacrificing the sensitivity. Some experimental results of full color holograms recorded by the single beam Lippmann method (Denisyuk configuration) are presented.

  15. Methylene Blue: The Long and Winding Road From Stain to Brain: Part 2.

    PubMed

    Howland, Robert H

    2016-10-01

    Methylene blue was the first synthetic drug ever used in medicine, having been used to treat clinical pain syndromes, malaria, and psychotic disorders more than one century ago. Methylene blue is a cationic thiazine dye with redox-cycling properties and a selective affinity for the nervous system. This drug also inhibits the activity of monoamine oxidase, nitric oxide synthase, and guanylyl cyclase, as well as tau protein aggregation; increases the release of neurotransmitters, such as serotonin and norepinephrine; reduces amyloid-beta levels; and increases cholinergic transmission. The action of methylene blue on multiple cellular and molecular targets justifies its investigation in various neuropsychiatric disorders. Investigations of methylene blue were instrumental in the serendipitous development of phenothiazine antipsychotic drugs. Although chlorpromazine is heralded as the first antipsychotic drug used in psychiatry, methylene blue is a phenothiazine drug that had been used to treat psychotic patients half a century earlier. It has also been studied in bipolar disorder and deserves further investigation for the treatment of unipolar and bipolar disorders. More recently, methylene blue has been the subject of preclinical and clinical investigations for cognitive dysfunction, dementia, and other neurodegenerative disorders. [Journal of Psychosocial Nursing and Mental Health Services, 54(10), 21-26.].

  16. Methylene blue solder re-absorption in microvascular anastomoses

    NASA Astrophysics Data System (ADS)

    Birch, Jeremy F.; Hepplewhite, J.; Frier, Malcolm; Bell, Peter R. F.

    2003-06-01

    Soldered vascular anastomoses have been reported using several chromophores but little is known of the optimal conditions for microvascular anastomosis. There are some indications of the optimal protein contents of a solder, and the effects of methylene blue on anastomotic strength. The effects of varying laser power density in vivo have also been described, showing a high rate of thrombosis with laser power over 22.9Wcm-2. However no evidence exists to describe how long the solder remains at the site of the anastomosis. Oz et al reported that the fibrin used in their study had been almost completely removed by 90 days but without objective evidence of solder removal. In order to address the issue of solder re-absorption from the site of an anastomosis we used radio-labelled albumin (I-125) incorporated into methylene blue based solder. This was investigated in both the situation of the patent and thrombosed anastomosis with anastomoses formed at high and low power. Iodine-125 (half life: 60.2 days) was covalently bonded to porcine albumin and mixed with the solder solution. Radio-iodine has been used over many years to determine protein turnover using either I-125 or I-131. Iodine-125 labelled human albumin is regularly used as a radiopharmaceutical tool for the determination of plasma volume. Radio-iodine has the advantages of not affecting protein metabolism and the label is rapidly excreted after metabolic breakdown. Labelling with chromium (Cr-51) causes protein denaturation and is lost from the protein with time. Labelled albumin has been reported in human studies over a 21-day period, with similar results reported by Matthews. Most significantly McFarlane reported a different rate of catabolism of I-131 and I-125 over a 22-day period. The conclusion from this is that the rate of iodine clearance is a good indicator of protein catabolism. In parallel with the surgery a series of blank standards were prepared with a known mass of solder to correct for isotope

  17. Sonocatalytic Methylene Blue in The Presence of Fe3O4-CuO-TiO2 Nanocomposites Heterostructure

    NASA Astrophysics Data System (ADS)

    Fauzian, Malleo; Jalaludin, Shofianina; Taufik, Ardiansyah; Saleh, Rosari

    2016-04-01

    In this work, the emphasis was mainly placed on investigating the sonocatalytic activity of Fe3O4-CuO-TiO2 nanocomposites heterostructure. The prepared samples were characterized by X-ray diffraction (XRD), Vibrating Sample Magnetometer (VSM), Brunauer-Emmett-Teller (BET) Surface Area Analysis. Methylene blue dye was selected to examine the sonocatalytic activity of Fe3O4-CuO-TiO2 nanocomposites heterostructure. The degradation reaction processes were monitored by UV-vis spectrophotometer. The influence on the activity of the Fe3O4-CuO-TiO2 nanocomposites heterostructure such as TiO2 loading was studied. The sonocatalyst Fe3O4-CuO-TiO2 with molar ratio of 1:1:5 showed the highest sonocatalytic activity. At last, the experiment also indicated that holes are the main reactive species in the photodegradation mechanism in methylene blue.

  18. Methylene blue inhibits function of the 5-HT transporter

    PubMed Central

    Oz, Murat; Isaev, Dmytro; Lorke, Dietrich E; Hasan, Muhammed; Petroianu, Georg; Shippenberg, Toni S

    2012-01-01

    BACKGROUND AND PURPOSE Methylene blue (MB) is commonly employed as a treatment for methaemoglobinaemia, malaria and vasoplegic shock. An increasing number of studies indicate that MB can cause 5-HT toxicity when administered with a 5-HT reuptake inhibitor. MB is a potent inhibitor of monoamine oxidases, but other targets that may contribute to MB toxicity have not been identified. Given the role of the 5-HT transporter (SERT) in the regulation of extracellular 5-HT concentrations, the present study aimed to characterize the effect of MB on SERT. EXPERIMENTAL APPROACH Live cell imaging, in conjunction with the fluorescent SERT substrate 4-(4-(dimethylamino)-styryl)-N-methylpyridinium (ASP+), [3H]5-HT uptake and whole-cell patch-clamp techniques were employed to examine the effects of MB on SERT function. KEY RESULTS In EM4 cells expressing GFP-tagged human SERT (hSERT), MB concentration-dependently inhibited ASP+ accumulation (IC50: 1.4 ± 0.3 µM). A similar effect was observed in N2A cells. Uptake of [3H]5-HT was decreased by MB pretreatment. Furthermore, patch-clamp studies in hSERT expressing cells indicated that MB significantly inhibited 5-HT-evoked ion currents. Pretreatment with 8-Br-cGMP did not alter the inhibitory effect of MB on hSERT activity, and intracellular Ca2+ levels remained unchanged during MB application. Further experiments revealed that ASP+ binding to cell surface hSERT was reduced after MB treatment. In whole-cell radioligand experiments, exposure to MB (10 µM; 10 min) did not alter surface binding of the SERT ligand [125I]RTI-55. CONCLUSIONS AND IMPLICATIONS MB modulated SERT function and suggested that SERT may be an additional target upon which MB acts to produce 5-HT toxicity. PMID:21542830

  19. Functional inactivation of lymphocytes by methylene blue with visible light.

    PubMed

    Zhang, Bo; Cheng, Zhenzhen; Mo, Qin; Wang, Li; Wang, Xun; Wu, Xiaofei; Jia, Yao; Huang, Yuwen

    2015-10-01

    Transfusion of allogeneic white blood cells (WBCs) may cause adverse reactions in immunocompromised recipients, including transfusion-associated graft-versus-host disease (TA-GVHD), which is often fatal and incurable. In this study, the in vitro effect of methylene blue with visible light (MB + L) treatment on lymphocyte proliferation and cytokine production was measured to investigate whether MB + L can be used to prevent immune reactions that result from transfused lymphocytes. WBCs and 3 μM of MB were mixed and transferred into medical PVC bags, which were then exposed to visible light. Gamma irradiation was conducted as a parallel positive control. The cells without treatment were used as untreated group. All the groups were tested for the ability of cell proliferation and cytokine production upon stimulation. After incubation with mitogen phytohemagglutinin (PHA) or plate-bound anti-CD3 plus anti-CD28, the proliferation of MB + L/gamma-irradiation treated lymphocytes was significantly inhibited (P < 0.01) as compared to the untreated ones; the proliferation inhibitive rate of the MB + L group was even higher than that of gamma-irradiated cells (73.77% ± 28.75% vs. 44.72% ± 38.20%). MB + L treated cells incubated up to 7 days with PHA also showed no significant proliferation. The levels of TNF-α, IFN-γ, IL-6, IL-8, IL-10 and IL-1β present in the supernatant of MB + L treated lymphocytes upon stimulation were significantly lower than those of untreated lymphocytes. These results demonstrated that MB + L treatment functionally and irreversibly inactivated lymphocytes by inhibiting lymphocyte proliferation and the production of cytokines. MB + L treatment might be a promising method for the prevention of adverse immune responses caused by WBCs.

  20. Beneficial network effects of methylene blue in an amnestic model

    PubMed Central

    Riha, Penny D.; Rojas, Julio C.; Gonzalez-Lima, F.

    2010-01-01

    Posterior cingulate/retrosplenial cortex (PCC) hypometabolism is a common feature in amnestic mild cognitive impairment and Alzheimer’s disease. In rats, PCC hypometabolism induced by mitochondrial dysfunction induces oxidative damage, neurodegeneration and memory deficits. USP methylene blue (MB) is a diaminophenothiazine drug with antioxidant and metabolic-enhancing properties. In rats, MB facilitates memory and prevents neurodegeneration induced by mitochondrial dysfunction. This study tested the memory-enhancing properties of systemic MB in rats that received an infusion of sodium azide, a cytochrome oxidase inhibitor, directly into the PCC. Lesion volumes were estimated with unbiased stereology. MB’s network-level mechanism of action was analyzed using graph theory and structural equation modeling based on cytochrome oxidase histochemistry-derived metabolic mapping data. Sodium azide infusions induced PCC hypometabolism and impaired visuospatial memory in a holeboard food-search task. Isolated PCC cytochrome oxidase inhibition disrupted the cingulo-thalamo-hippocampal effective connectivity, decreased the PCC functional networks and created functional redundancy within the thalamus. An intraperitoneal dose of 4 mg/kg MB prevented the memory impairment, reduced the PCC metabolic lesion volume and partially restored the cingulo-thalamo-hippocampal network effects. The effects of MB were dependent upon the local sub-network necessary for memory retrieval. The data support that MB’s metabolic-enhancing effects are contingent upon the neural context, and that MB is able to boost coherent and orchestrated adaptations in response to physical alterations to the network involved in visuospatial memory. These results implicate MB as a candidate intervention to improve memory. Because of its neuroprotective properties, MB may have disease-modifying effects in amnestic conditions associated with hypometabolism. PMID:21087672

  1. Photocatalytic activity enhancement of anatase-graphene nanocomposite for methylene removal: Degradation and kinetics

    NASA Astrophysics Data System (ADS)

    Rezaei, Mostafa; Salem, Shiva

    2016-10-01

    In the present research, the TiO2-graphene nanocomposite was synthesized by an eco-friendly method. The blackberry juice was introduced to graphene oxide (GO) as a reducing agent to produce the graphene nano-sheets. The nanocomposite of anatase-graphene was developed as a photocatalyst for the degradation of methylene blue, owing to the larger specific surface area and synergistic effect of reduced graphene oxide (RGO). The UV spectroscopy measurements showed that the prepared nanocomposite exhibited an excellent photocatalytic activity toward the methylene blue degradation. The rate of electron transfer of redox sheets is much higher than that observed on GO, indicating the applicability of proposed method for the production of anatase-RGO nanocomposite for treatment of water contaminated by cationic dye. The prepared materials were characterized with Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area measurement, scanning electron microscopy and transmission electron microscopy. A facile and rapid route was applied for the uniform deposition of anatase nanoparticles on the sheets. The resulting nanocomposite contained nanoparticles with a mean diameter of 10 nm. A mechanism for the photocatalytic activity of nanocomposite was suggested and the degradation reaction obeyed the second-order kinetics. It was concluded that the degradation kinetics is changed due to the reduction of GO in the presence of blackberry juice.

  2. Photocatalytic activity enhancement of anatase-graphene nanocomposite for methylene removal: Degradation and kinetics.

    PubMed

    Rezaei, Mostafa; Salem, Shiva

    2016-10-05

    In the present research, the TiO2-graphene nanocomposite was synthesized by an eco-friendly method. The blackberry juice was introduced to graphene oxide (GO) as a reducing agent to produce the graphene nano-sheets. The nanocomposite of anatase-graphene was developed as a photocatalyst for the degradation of methylene blue, owing to the larger specific surface area and synergistic effect of reduced graphene oxide (RGO). The UV spectroscopy measurements showed that the prepared nanocomposite exhibited an excellent photocatalytic activity toward the methylene blue degradation. The rate of electron transfer of redox sheets is much higher than that observed on GO, indicating the applicability of proposed method for the production of anatase-RGO nanocomposite for treatment of water contaminated by cationic dye. The prepared materials were characterized with Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area measurement, scanning electron microscopy and transmission electron microscopy. A facile and rapid route was applied for the uniform deposition of anatase nanoparticles on the sheets. The resulting nanocomposite contained nanoparticles with a mean diameter of 10nm. A mechanism for the photocatalytic activity of nanocomposite was suggested and the degradation reaction obeyed the second-order kinetics. It was concluded that the degradation kinetics is changed due to the reduction of GO in the presence of blackberry juice.

  3. Ultra-efficient photocatalytic deprivation of methylene blue and biological activities of biogenic silver nanoparticles.

    PubMed

    Khan, Arif Ullah; Yuan, Qipeng; Wei, Yun; Khan, Zia Ul Haq; Tahir, Kamran; Khan, Shahab Ullah; Ahmad, Aftab; Khan, Shafiullah; Nazir, Sadia; Khan, Faheem Ullah

    2016-06-01

    Phytosynthesis of metal nanoparticles is considered as a safe, cost-effective, and green approach. In this study, silver nanoparticles (AgNPs) were successfully synthesized using the aqueous extract of Lychee (Litchi chinensis) fruit peel and an aqueous solution of silver nitrate (AgNO3). The synthesized nanoparticles were characterized by several analytical techniques i.e. UV-Vis Spectroscopy, XRD (X-ray diffraction spectroscopy), EDX (electron dispersive X-ray), SAED (selected area electron diffraction), HRTEM (high-resolution transmission electron microscopy), and FTIR (Fourier transform infrared spectroscopy). HRTEM and XRD results indicated that the prepared AgNPs are spherical in shape, well dispersed and face centered cubic crystalline. AgNPs showed potent antibacterial properties against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. The minimum inhibitory concentration (MIC) values were 125μg against E. coli and 62.5μg against both S. aureus and B. subtilis. AgNPs induce efficient cell constituent release from bacterial cells, which indicates the deterioration of cytoplasmic membrane. Moreover, antioxidant studies on the as-synthesized nanoparticles reveal efficient scavenging of the stable or harmful DPPH free radical. The cytotoxicity assay confirmed that biosynthesized AgNPs are nontoxic to normal healthy RBCs. AgNPs exhibited consistent release of Ag(+) determined by ICP-AES analysis. AgNPs exhibited extraordinary photocatalytic degradation (99.24%) of methylene blue. On the other hand, commercial silver nanoparticles have moderate biological activities against the tested bacterial strains and negligible photocatalytic degradation of methylene blue. The significant biological and photocatalytic activities of the biosynthesized silver nanoparticles are attributed to their small size, spherical morphology and high dispersion.

  4. Hydrothermal synthesis of CuO micro-/nanostructures and their applications in the oxidative degradation of methylene blue and non-enzymatic sensing of glucose/H2O2.

    PubMed

    Prathap, M U Anu; Kaur, Balwinder; Srivastava, Rajendra

    2012-03-15

    In this paper, we report on the amino acids-/citric acid-/tartaric acid-assisted morphologically controlled hydrothermal synthesis of micro-/nanostructured crystalline copper oxides (CuO). These oxides were characterized by means of X-ray diffraction, nitrogen sorption, scanning electron microscopy, Fourier transform infrared, and UV-visible spectroscopy. The surface area of metal oxides depends on the amino acid used in the synthesis. The formation mechanisms were proposed based on the experimental results, which show that amino acid/citric acid/tartaric acid and hydrothermal time play an important role in tuning the morphology and structure of CuO. The catalytic activity of as-synthesized CuO was demonstrated by catalytic oxidation of methylene blue in the presence of hydrogen peroxide (H(2)O(2)). CuO synthesized using tyrosine was found to be the best catalyst compared to a variety of CuO synthesized in this study. CuO (synthesized in this study)-modified electrodes were used for the construction of non-enzymatic sensors, which displayed excellent electrocatalytic response for the detection of H(2)O(2) and glucose compared to conventional CuO. The high electrocatalytic response observed for the CuO synthesized using tyrosine can be correlated with the large surface area, which enhances the accessibility of H(2)O(2)/glucose molecule to the active site that results in high observed current. The methodology adopted in the present study provides a new platform for the fabrication of CuO-based high-performance glucose and other biosensors.

  5. Time resolved spectroscopic studies of methylene blue and phenothiazine derivatives used for bacteria inactivation

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Cesario, Thomas C.; Rentzepis, Peter M.

    2010-09-01

    Phenothiazine dyes are known to inactivate bacteria in whole blood and plasma caused by the singlet oxygen photo generated by these dyes. Methylene blue (MB), 1,9-dimethyl-methylene blue (DMB) and toluidine blue (TB) transient singlet and triplet states spectra and their formation and decay kinetics have been measured by time resolved spectroscopy. The triplet state formation and singlet oxygen quantum yields in water are found to be approximately the same in MB and DMB. Therefore, based on our data we propose that although singlet oxygen is highly important as previously stated, the rate of inactivation is determined by the binding of the dye to the bacteria.

  6. Methylene blue modulates transendothelial migration of peripheral blood cells.

    PubMed

    Werner, Isabella; Guo, Fengwei; Bogert, Nicolai V; Stock, Ulrich A; Meybohm, Patrick; Moritz, Anton; Beiras-Fernandez, Andres

    2013-01-01

    Vasoplegia is a severe complication after cardiac surgery. Within the last years the administration of nitric oxide synthase inhibitor methylene blue (MB) became a new therapeutic strategy. Our aim was to investigate the role of MB on transendothelial migration of circulating blood cells, the potential role of cyclic cGMP, eNOS and iNOS in this process, and the influence of MB on endothelial cell apoptosis. Human vascular endothelial cells (HuMEC-1) were treated for 30 minutes or 2 hours with different concentrations of MB. Inflammation was mimicked by LPS stimulation prior and after MB. Transmigration of PBMCs and T-Lymphocytes through the treated endothelial cells was investigated. The influence of MB upon the different subsets of PBMCs (Granulocytes, T- and B-Lymphocytes, and Monocytes) was assessed after transmigration by means of flow-cytometry. The effect of MB on cell apoptosis was evaluated using Annexin-V and Propidium Iodide stainings. Analyses of the expression of cyclic cGMP, eNOS and iNOS were performed by means of RT-PCR and Western Blot. Results were analyzed using unpaired Students T-test. Analysis of endothelial cell apoptosis by MB indicated a dose-dependent increase of apoptotic cells. We observed time- and dose-dependent effects of MB on transendothelial migration of PBMCs. The prophylactic administration of MB led to an increase of transendothelial migration of PBMCs but not Jurkat cells. Furthermore, HuMEC-1 secretion of cGMP correlated with iNOS expression after MB administration but not with eNOS expression. Expression of these molecules was reduced after MB administration at protein level. This study clearly reveals that endothelial response to MB is dose- and especially time-dependent. MB shows different effects on circulating blood cell-subtypes, and modifies the release patterns of eNOS, iNOS, and cGMP. The transendothelial migration is modulated after treatment with MB. Furthermore, MB provokes apoptosis of endothelial cells in a dose

  7. Complexation between carrageenan and methylene blue for sensor design

    NASA Astrophysics Data System (ADS)

    Ling, Yew Pei; Heng, Lee Yook

    2013-11-01

    Theoretical studies on the methylene blue (MB)-carrageenans complexation at solution and solid states have been carried out via ultraviolet spectrophotoscopy and reflectometry methods. The equilibrium constant (Ka) of the MBcarrageenans complexation follows the order of Iota > Lambda > Kappa carrageenans, which indicated Iota-carrageenan forms a stable complex. MB-carrageenan complexation reaction showed decrease in Ka value from 210.71 ppm-1 to 114.57 ppm-1 when the reaction temperature increased from 298 K to 323 K. Le Chatelier's principle and mass action law explained that the MB-carrageenan complexation was an exothermic reaction (ΔH=-18.54 kJmol-1) that release heat. Thus MB-carrageenan complex was less stable at high temperature and tend to dissociate into free MB and carrageenan molecules. It was also supported by the van't Hoff equation. The reaction is a spontaneous process (ΔG=-13.23 kJmol-1) where the randomness of the molecules reduced (ΔS=-17.83 Jmol-1K-1) due to complexation. Besides, linear regression of the concentration and absorption of the MB-carrageenan reaction obeys the Beer Lambert law, which elucidated that the complexation process was not affected by any concentration dependent factors such as aggregation and self-quenching. Moreover, linear Benesi Hilderbrend plot revealed that the interaction between MB and carrageenan was a reversible and stoichiometric reaction with 1:1 ratio. However, the molar extinction coefficient (ɛ) and molar adsorption coefficient (μa) of the MB-carrageenan complex were lower compared to free MB, described that the complex was less adsorptive. The sensor constructed based on these theoretical investigations showed response behavior that was similar with solution test as both have attraction for carrageenans in the sequence of Iota-, Lambda-, Kappa- carrageenans. Likewise, carrageenan sensor was more selective towards Iota-carrageenan than to Lambda- and Kappa-carrageenans, and no response observed when

  8. Urea enhances the photodynamic efficiency of methylene blue.

    PubMed

    Nuñez, Silvia C; Yoshimura, Tania M; Ribeiro, Martha S; Junqueira, Helena C; Maciel, Cleiton; Coutinho-Neto, Maurício D; Baptista, Maurício S

    2015-09-01

    Methylene blue (MB) is a well-known photosensitizer used mostly for antimicrobial photodynamic therapy (APDT). MB tends to aggregate, interfering negatively with its singlet oxygen generation, because MB aggregates lean towards electron transfer reactions, instead of energy transfer with oxygen. In order to avoid MB aggregation we tested the effect of urea, which destabilizes solute-solute interactions. The antimicrobial efficiency of MB (30 μM) either in water or in 2M aqueous urea solution was tested against a fungus (Candida albicans). Samples were kept in the dark and irradiation was performed with a light emitting diode (λ = 645 nm). Without urea, 9 min of irradiation was needed to achieve complete microbial eradication. In urea solution, complete eradication was obtained with 6 min illumination (light energy of 14.4 J). The higher efficiency of MB/urea solution was correlated with a smaller concentration of dimers, even in the presence of the microorganisms. Monomer to dimer concentration ratios were extracted from the absorption spectra of MB solutions measured as a function of MB concentration at different temperatures and at different concentrations of sodium chloride and urea. Dimerization equilibrium decreased by 3 and 6 times in 1 and 2M urea, respectively, and increased by a factor of 6 in 1M sodium chloride. The destabilization of aggregates by urea seems to be applied to other photosensitizers, since urea also destabilized aggregation of Meso-tetra(4-n-methyl-pyridyl)porphyrin, which is a positively charged porphyrin. We showed that urea destabilizes MB aggregates mainly by causing a decrease in the enthalpic gain of dimerization, which was exactly the opposite of the effect of sodium chloride. In order to understand this phenomenon at the molecular level, we computed the free energy for the dimer association process (ΔG(dimer)) in aqueous solution as well as its enthalpic component in aqueous and in aqueous/urea solutions by molecular dynamics

  9. Rapid alkaline methylene blue supravital staining for assessment of anterior segment infections

    PubMed Central

    Kiuchi, Katsuji

    2016-01-01

    Purpose To present the Löffler’s alkaline methylene blue technique of staining eye discharges in eyes with anterior segment infections. Method The Löffler’s alkaline methylene blue staining method is a simple staining technique that can be used to differentiate bacterial, viral, and fungal infections. It is a cationic dye that stains cells blue because the positively charged dye is attracted to negatively charged particles such as polyphosphates, DNAs, and RNAs. Specimens collected from patients by swabbing are smeared onto microscope slides and the methylene blue solution is dropped on the slide. The slide is covered with a glass cover slip and examined under a microscope. The entire time from the collection to the viewing is about 30 seconds. Results Histopathological images of the conjunctival epithelial cells and neutrophils in eye discharges were dyed blue and the nuclei were stained more intensely blue. Bacterial infections consisted mainly of neutrophils, and viral infections consisted mainly of lymphocytes. Conclusions Löffler’s alkaline methylene blue staining can be done in about 30 seconds for diagnosis. Even though this is a one color stain, it is possible to infer the cause of the infection by detection of the absence of bacteria and/or fungi in context of the differential distribution of neutrophils and lymphocytes. PMID:27784986

  10. Optimization of methylene blue using Ca(2+) and Zn(2+) bio-polymer hydrogel beads: A comparative study.

    PubMed

    Kumar, M; Tamilarasan, R; Arthanareeswaran, G; Ismail, A F

    2015-11-01

    Recently noted that the methylene blue cause severe central nervous system toxicity. It is essential to optimize the methylene blue from aqueous environment. In this study, a comparison of an optimization of methylene blue was investigated by using modified Ca(2+) and Zn(2+) bio-polymer hydrogel beads. A batch mode study was conducted using various parameters like time, dye concentration, bio-polymer dose, pH and process temperature. The isotherms, kinetics, diffusion and thermodynamic studies were performed for feasibility of the optimization process. Freundlich and Langmuir isotherm equations were used for the prediction of isotherm parameters and correlated with dimensionless separation factor (RL). Pseudo-first order and pseudo-second order Lagegren's kinetic equations were used for the correlation of kinetic parameters. Intraparticle diffusion model was employed for diffusion of the optimization process. The Fourier Transform Infrared Spectroscopy (FTIR) shows different absorbent peaks of Ca(2+) and Zn(2+) beads and the morphology of the bio-polymer material analyzed with Scanning Electron Microscope (SEM). The TG & DTA studies show that good thermal stability with less humidity without production of any non-degraded products.

  11. Methylene Blue Assay for Estimation of Regenerative Re-Epithelialization In Vivo.

    PubMed

    Milyavsky, Maresha; Dickie, Renee

    2017-02-01

    The rapidity with which epithelial cells cover a wound surface helps determine whether scarring or scar-less healing results. As methylene blue is a vital dye that is absorbed by damaged tissue but not undamaged epidermis, it can be used to assess wound closure. We sought to develop a quantitative methylene blue exclusion assay to estimate the timeframe for re-epithelialization in regenerating appendages in zebrafish and axolotls, two classic model systems of regeneration. Following application of methylene blue to the amputation plane and extensive washing, the regenerating tail was imaged in vivo until staining was no longer visible. The percent area of the amputation plane positive for methylene blue, representing the area of the amputation plane not yet re-epithelialized, was measured for each time point. The loss of methylene blue occurred rapidly, within ~2.5 h in larval and juvenile axolotls and <1 h in adult zebrafish, consistent with high rates of re-epithelialization in these models of regeneration. The assay allows simple, rapid estimation of the time course for regenerative re-epithelialization without affecting subsequent regenerative ability. This technique will permit comparison of re-epithelialization across different strains and stages, as well as under the influence of various pharmacological inhibitors that affect regeneration.

  12. Decolourization of Methylene Blue in Water Using Bentonite Impregnated with Ti and Ag as Photocatalyst.

    PubMed

    Wu, Edward Ming-Yang; Kuo, Shu-Lung

    2015-08-01

    This article used bentonite impregnated with titanium and silver, respectively, as photocatalyst, to degrade methylene blue (MB) under conditions of MB solutions exposed to sodium lamp and sunlight. Due to the semi-conducting properties of synthesized bentonite catalysts, when exposed to sodium lamp and sunlight, catalyst particles are excited for photocatalysis to achieve decolourization. After an FT-IR analysis, this study finds that smectite catalysts have significant and complicated wave crests between the fingerprint area with wave numbers 415~600 cm⁻¹ and 750~1170 cm⁻¹. The bentonite impregnated with Ti(4+) (Sm-Ti) and with Ag⁺ (Sm-Ag) removes MB through the mechanisms of adsorption and degradation, while the commercial product of titanium dioxide (TiO₂) only exhibits the capability of MB degradation. At present, a heterogeneous photocatalytic system has been fully applied for use in daily life, with its efficiency determined by the free radical action of electrons and holes, the generation efficiency of ·OH.

  13. Adsorption of chlorophenol, chloroaniline and methylene blue on fuel oil fly ash.

    PubMed

    Andini, Salvatore; Cioffi, Raffaele; Colangelo, Francesco; Montagnaro, Fabio; Santoro, Luciano

    2008-09-15

    Fuel oil fly ash has been tested as low-cost carbon-based adsorbent of 2-chlorophenol (CP), 2-chloroaniline (CA) and methylene blue (MB) from aqueous solutions. In all the cases the adsorption was found to be of cooperative type. Different adsorption capacities were found for the three organics. Specifically, it was highest for 2-chlorophenol, reaching about 70 mg g(-1), and quite lower in the other two cases, that is about 47 and 36 mg g(-1) for methylene blue and 2-chloroaniline, respectively. Varying the initial pH and adding KCl were found to have different effects on the adsorption of the three organics. In particular, the presence of other ions had no effect on the adsorption of methylene blue, adverse effect in the case of 2-chlorophenol and enhancing effect in the case of 2-chloroaniline.

  14. Methylene blue and parathyroid adenoma localization: Three new cases of a rare cutaneous complication.

    PubMed

    Lieberman, Elliot D; Thambi, Rakhi; Pytynia, Kristen B

    2016-02-01

    Methylene blue has been safely used for the localization of parathyroid glands during parathyroidectomy, and only a few adverse effects have been documented. Methylene blue administration as a cause of pulse-oximetry-related skin injury is extremely rare. We describe 2 such cases in patients who developed a blister on the second digit at the pulse oximetry site after an uncomplicated excision of a parathyroid adenoma. In another case, a patient became bradycardic intraoperatively; she was successfully resuscitated, but she incurred a second-degree burn at the pulse oximetry site. In all 3 cases, the burns resolved with local wound care. We publish this report to alert surgeons and anesthesiologists to the risk of skin complications with the use of high-dose intraoperative methylene blue.

  15. Utility of methylene blue for the reversal of excessive levels of methemoglobin

    SciTech Connect

    Vick, J.; Von Bredow, J.; Brown, L.; Kaminskis, A.; Bossone, C.

    1993-05-13

    Many new prophylactic and therapeutic compounds are being studied as potential sources of methemoglobin useful in counteracting the lethal effects of cyanide intoxication. The formation of methemoglobin also leads to a reduction in the blood oxygen carrying capacity which may, in extreme cases, lead to lethal consequences. The i.v. administration of Methylene blue rapidly reverses methemoglobin to hemoglobin. Unanticipated high levels of methemoglobin (65 - 85%) in three sheep exposed to propiophenone derivatives led to a lethal outcome in one untreated sheep and complete recovery in two sheep which were treated with 3.0 mg/kg methylene blue i.v. methemoglobin was reduced to safe levels within minutes following administration. A similar exposure of dogs to propriophenone derivatives led to high levels (77 - 78%) of methemoglobin which were readily reversed following the intravenous administration of the same dose of methylene blue.

  16. Multimodal Randomized Functional MR Imaging of the Effects of Methylene Blue in the Human Brain.

    PubMed

    Rodriguez, Pavel; Zhou, Wei; Barrett, Douglas W; Altmeyer, Wilson; Gutierrez, Juan E; Li, Jinqi; Lancaster, Jack L; Gonzalez-Lima, Francisco; Duong, Timothy Q

    2016-11-01

    Purpose To investigate the sustained-attention and memory-enhancing neural correlates of the oral administration of methylene blue in the healthy human brain. Materials and Methods The institutional review board approved this prospective, HIPAA-compliant, randomized, double-blinded, placebo-controlled clinical trial, and all patients provided informed consent. Twenty-six subjects (age range, 22-62 years) were enrolled. Functional magnetic resonance (MR) imaging was performed with a psychomotor vigilance task (sustained attention) and delayed match-to-sample tasks (short-term memory) before and 1 hour after administration of low-dose methylene blue or a placebo. Cerebrovascular reactivity effects were also measured with the carbon dioxide challenge, in which a 2 × 2 repeated-measures analysis of variance was performed with a drug (methylene blue vs placebo) and time (before vs after administration of the drug) as factors to assess drug × time between group interactions. Multiple comparison correction was applied, with cluster-corrected P < .05 indicating a significant difference. Results Administration of methylene blue increased response in the bilateral insular cortex during a psychomotor vigilance task (Z = 2.9-3.4, P = .01-.008) and functional MR imaging response during a short-term memory task involving the prefrontal, parietal, and occipital cortex (Z = 2.9-4.2, P = .03-.0003). Methylene blue was also associated with a 7% increase in correct responses during memory retrieval (P = .01). Conclusion Low-dose methylene blue can increase functional MR imaging activity during sustained attention and short-term memory tasks and enhance memory retrieval. (©) RSNA, 2016 Online supplemental material is available for this article.

  17. Aggregation of 1,3,7-trimethylxanthine with methylene blue in aqueous solution

    NASA Astrophysics Data System (ADS)

    Baranovskii, S. F.; Bolotin, P. A.; Evstigneev, M. P.

    2006-03-01

    We have studied self-association of aromatic molecules of the thiazine dye methylene blue in aqueous solution, using a dimer model. We have determined the dimerization equilibrium constant for the dye molecules KD = 3900 ± 800 M-1 at T = 293 K. We have decomposed the experimental spectrum into dimer and monomer components. Using the ratio of the molar absorption coefficients for two absorption bands of the dimer spectrum, we obtained the “average” value of the angle between the electronic transition moments of the molecules in the dimers, α = 48°. We have studied heteroassociation of methylene blue (MB) and 1,3,7-trimethylxanthine (caffeine) molecules in aqueous solution. We have calculated the heteroassociation constant as 200 ± 34 M-1. We conclude that heteroassociation of methylene blue and caffeine molecules leads to a lower effective dye concentration in solution, which hypothetically may affect its biological activity. We have determined the values of the Gibbs free energy, the enthalpy, and the entropy for dimerization of methylene blue molecules: ΔG293 = -(20 ± 3) kJ/mol, ΔH = -(25 ± 9) kJ/mol, Δ S293 = -(17 ± 6) J/mol·K; and for methylene blue-caffeine heteroassociation: ΔG293 = -(13 ± 3) kJ/mol, ΔH = -(14 ± 10) kJ/mol, ΔS293 = -(2.4 ± 0.2) J/mol·K, respectively. We have shown that the methylene blue aggregates and the heteroassociates with caffeine are predominantly stabilized by dispersion interactions between the chromophore molecules in the associates.

  18. Viral Inactivation of Human Osteochondral Grafts with Methylene Blue and Light

    PubMed Central

    Zhao, Zhixing; Call, Gazell M.; Gao, Jizong; Yao, Jian Q.

    2014-01-01

    Objective: Cartilage injury is one of the most common disorders of synovial joints. Fresh osteochondral allografts are becoming a standard treatment; however, they are supply constrained with a potential risk of disease transmission. There are no known virucidal processes available for osteochondral allografts and most methods presently available are detrimental to cartilage. Methylene blue light treatment has been shown to be successful in the literature for viral inactivation of fresh frozen plasma. The purpose of this study was to determine the capacity of methylene blue light treatment to inactivate a panel of clinically relevant viruses inoculated onto osteochondral allografts. Design: Osteochondral grafts recovered from human cadaveric knees were inoculated with one of the following viruses: bovine viral diarrhea virus (BVDV), hepatitis A virus (HAV), human immunodeficiency virus type 1 (HIV-1), porcine parvovirus (PPV), and pseudorabies virus (PrV). The samples were processed through a methylene blue light treatment, which consisted of an initial soak in nonilluminated circulating methylene blue at ambient temperature, followed by light exposure with circulating methylene blue at cool temperatures. The final titer was compared with the recovery control for the viral log reduction. Results: HIV-1, BVDV, and PrV were reduced to nondetectable levels while HAV and PPV were reduced by 3.1 and 5.6 logs, respectively. Conclusions: The methylene blue light treatment was effective in reducing (a) enveloped DNA and RNA viruses to nondetectable levels and (b) nonenveloped DNA and RNA viruses of inoculated human osteochondral grafts by 3.1 to 5.6 logs. This study demonstrates the first practical method for significantly reducing viral load in osteochondral implants. PMID:26069682

  19. Snapshots of mammary gland interstitial cells: methylene-blue vital staining and c-kit immunopositivity.

    PubMed

    Popescu, L M; Andrei, F; Hinescu, M E

    2005-01-01

    We show here that methylene-blue supravital staining of specimens from normal human mammary gland reveals (selectively) interstitial (stromal) cells, with 2-3 long (20-80 microm), thin, moniliform processes. Such cells appear c-kit/CD117 positive, either by immunohistochemistry (IHC) or immunofluorescence (IF). Since these features (affinity for methylene blue, c-kit positivity, and characteristic processes) define archetypal interstitial cells of Cajal (ICC) in light microscopy, our results suggest the existence of Cajal-like cells in the interstitium of human normal mammary gland.

  20. Endonyx toenail onychomycosis caused by Trichophyton rubrum: treatment with photodynamic therapy based on methylene blue dye.

    PubMed

    Souza, Linton Wallis Figueiredo; Souza, Simone Vilas Trancoso; Botelho, Ana Cristina de Carvalho

    2013-01-01

    This study shows the effectiveness of photodynamic therapy based on methylene blue dye for the treatment of endonyx toenail onychomycosis. Four patients with endonyx onychomycosis caused by Trichophyton rubrum were treated with 2% methylene blue aqueous solution irradiated with light emission diode at 630 nm and an energy density of 36 J/cm2 for 6 months at 2-week intervals. The preliminary study showed the effectiveness of this therapy in the treatment of endonyx onychomycosis, and also indicated that the disease can be caused by T. rubrum.

  1. Towards optimum diffraction efficiency for methylene blue sensitized dichromated gelatin holograms

    NASA Astrophysics Data System (ADS)

    Changkakoti, R.; Pappu, S. V.

    1989-08-01

    A systematic investigation has been carried out into the optimization of diffraction efficiency ( η) of methylene blue sensitized dichromated gelatin (MBDCG) holograms. The influence of the following parameters on η have been studied: prehardener concentration ( CH), concentrations of ammonium dichromate ( CA) and methylene blue ( CM) as photosensitizers, and exposure ( E). This study revealed that with CH ≃ 0.5, CA ≃ 30, CM ≃ 0.3, and E ≃ 400-600, optimum diffraction efficiency of over 80%, can be easily achieved in MBDCG holograms.

  2. Determination of the hydrogenase status of individual legume nodules by a methylene blue reduction assay.

    PubMed

    Lambert, G R; Hanus, F J; Russell, S A; Evans, H J

    1985-08-01

    We adapted a method for the rapid screening of colonies of free-living Rhizobium japonicum for hydrogenase activity to determine the hydrogenase status of individual soybean nodules. Crude bacteroid suspensions from nodules containing strains known to be hydrogen uptake positive (Hup) caused a localized decolorization of filter paper disks, whereas suspensions from nodules arising from inoculation with hydrogen uptake-negative (Hup) mutants or strains did not decolorize the disks. The reliability of the method was demonstrated by its successful application to 29 slow-growing rhizobia. The Hup phenotype on methylene blue filters agreed with that determined amperometrically with either methylene blue or oxygen as the electron acceptor.

  3. Efficacy of Methylene Blue in Sentinel Lymph Node Biopsy for Early Breast Cancer

    PubMed Central

    Özdemir, Altan; Mayir, Burhan; Demirbakan, Kenan; Oygür, Nezihi

    2014-01-01

    Objective Sentinel lymph node biopsy is the recommended approach in the evaluation of axilla during breast cancer surgery. In this study, results of patients who underwent methylene blue sentinel lymph node biopsy were evaluated. Materials and Methods The study included 32 female patients with T1 and T2 tumors. 5 ml of 1% methylene blue was injected into the peritumoral area or around the cavity. The axillary sentinel lymph node was found and removed, and then axillary dissection was performed. The sentinel lymph node and axillary dissection specimen were histopathologically examined and the results were compared. Results The sentinel lymph node was found in 30 (94%) patients. Lymph node metastasis was not observed in 17 patients in both the sentinel lymph node and axilla. Two patients had metastasis in the axilla although this was not detected in sentinel lymph node. Eleven patients had metastasis both in the sentinel lymph node and in the axilla. The accuracy rate was 93%, and the false negativity rate was identified as 15%. Conclusion Sentinel lymph node biopsy by methylene blue is a method that can be applied with high accuracy. Methylene blue can be considered as an alternative to isosulphane blue in sentinel lymph node biopsy.

  4. The monoamine oxidase inhibition properties of selected structural analogues of methylene blue.

    PubMed

    Delport, Anzelle; Harvey, Brian H; Petzer, Anél; Petzer, Jacobus P

    2017-04-01

    The thionine dye, methylene blue (MB), is a potent inhibitor of monoamine oxidase (MAO) A, a property that may, at least in part, mediate its antidepressant effects in humans and animals. The central inhibition of MAO-A by MB has also been linked to serotonin toxicity (ST) which may arise when MB is used in combination with serotonergic drugs. Structural analogues and the principal metabolite of MB, azure B, have also been reported to inhibit the MAO enzymes, with all compounds exhibiting specificity for the MAO-A isoform. To expand on the structure-activity relationships (SARs) of MAO inhibition by MB analogues, the present study investigates the human MAO inhibition properties of five MB analogues: neutral red, Nile blue, new methylene blue, cresyl violet and 1,9-dimethyl methylene blue. Similar to MB, these analogues also are specific MAO-A inhibitors with cresyl violet (IC50=0.0037μM), Nile blue (IC50=0.0077μM) and 1,9-dimethyl methylene blue (IC50=0.018μM) exhibiting higher potency inhibition compared to MB (IC50=0.07μM). Nile blue also represents a potent MAO-B inhibitor with an IC50 value of 0.012μM. From the results it may be concluded that non-thionine MB analogues (e.g. cresyl violet and Nile blue) also may exhibit potent MAO inhibition, a property which should be considered when using these compounds in pharmacological studies. Benzophenoxazines such as cresyl violet and Nile blue are, similar to phenothiazines (e.g. MB), representative of high potency MAO-A inhibitors with a potential risk of ST.

  5. Chemically derived luminescent graphene oxide nanosheets and its sunlight driven photocatalytic activity against methylene blue dye

    NASA Astrophysics Data System (ADS)

    Kumar, Sumeet; Kumar, Ashok

    2016-12-01

    In the present work, graphene oxide (GO) nanosheets (NSs) have been synthesized with precise control over their thickness and molecular structure. The existence of oxygen containing functional groups on GO NSs through chemical treatment confers remarkable optical properties on GO. XRD, TEM, Raman and FTIR techniques were used to confirm the phase and degree of oxidation, morphology, structural information and chemical structure of the synthesized GO NSs. UV-Vis. spectroscopy was employed to study the optical absorption properties of the synthesized GO NSs. The excitation wavelength dependent PL measurements of the synthesized GO NSs were carried out which could be useful for the design and development of GO based next generation optoelectronic devices. The most fascinating luminescent property of synthesized GO NSs is that its luminescence peak position can be easily tuned by only varying the excitation wavelength without significant changes in its size and chemical composition. In order to study the photocatalytic degradation of methylene blue (MB) dye using GO NSs as a photocatalyst, a sunlight driven photocatalytic activity has been performed. The degradation rate of MB dye becomes fast when GO NSs are added to the dye solution. The photodegradation efficiency of GO NSs is calculated to be 60%. The present results indicate that synthesized GO NSs can be used as sunlight active photocatalyst. The optimistic response to sunlight irradiation validates the potential of GO NSs in solar energy conversion.

  6. Comparison of methylene blue/gentian violet stain to Gram's stain for the rapid diagnosis of gonococcal urethritis in men.

    PubMed

    Taylor, Stephanie N; DiCarlo, Richard P; Martin, David H

    2011-11-01

    We compared a simple, one-step staining procedure using a mixture of methylene blue and gentian violet to Gram stain for the detection of gonococcal urethritis. The sensitivity and specificity of both Gram stain and methylene blue/gentian violet stain were 97.3% and 99.6%, respectively. There was a 100% correlation between the 2 methods.

  7. Mass transfer, kinetics and equilibrium studies for the biosorption of methylene blue using Paspalum notatum.

    PubMed

    Kumar, K Vasanth; Porkodi, K

    2007-07-19

    Batch experiments were carried out for the sorption of methylene blue onto Paspalum notatum. The operating variables studied were initial dye concentration, initial solution pH, adsorbent dosage and contact time. Experimental equilibrium data were fitted to Freundlich, Langmuir and Redlich-Peterson isotherms by non-linear regression method. Six error functions was used to determine the optimum isotherm by non-linear regression method. The present study shows r2 as the best error function to determine the parameters involved in both two- and three-parameter isotherms. Langmuir isotherm was found to be the optimum isotherm for methylene blue onto P. notatum. The monolayer methylene blue sorption capacity of P. notatum was found to be 31 mg/g. The kinetics of methylene blue onto P. notatum was found to follow a pseudo second order kinetics. A Boyd plot confirms the external mass transfer as the rate-limiting step in the dye sorption process. The influence of initial dye concentration on the dye sorption process was represented in the form of dimensionless mass transfer numbers (Sh/Sc0.33) and was found to vary as C(0)-5x10(-6).

  8. Methylene blue adsorption by algal biomass based materials: biosorbents characterization and process behaviour.

    PubMed

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2007-08-17

    Dead algal biomass is a natural material that serves as a basis for developing a new family of sorbent materials potentially suitable for many industrial applications. In this work an algal industrial waste from agar extraction process, algae Gelidium and a composite material obtained by immobilization of the algal waste with polyacrylonitrile (PAN) were physical characterized and used as biosorbents for dyes removal using methylene blue as model. The apparent and real densities and the porosity of biosorbents particles were determined by mercury porosimetry and helium picnometry. The methylene blue adsorption in the liquid phase was the method chosen to calculate the specific surface area of biosorbent particles as it seems to reproduce better the surface area accessible to metal ions in the biosorption process than the N2 adsorption-desorption dry method. The porous texture of the biosorbents particles was also studied. Equilibrium isotherms are well described by the Langmuir equation, giving maximum uptake capacities of 171, 104 and 74 mg g(-1), respectively for algae, algal waste and composite material. Kinetic experiments at different initial methylene blue concentrations were performed to evaluate the equilibrium time and the importance of the driving force to overcome mass transfer resistances. The pseudo-first-order and pseudo-second-order kinetic models adequately describe the kinetic data. The biosorbents used in this work proved to be promising materials for removing methylene blue from aqueous solutions.

  9. The feasibility of using methylene blue sensitized polyvinylalcohol film as a linear polarizer

    SciTech Connect

    Jyothilakshmi, K.; Anju, K. S.; Arathy, K.; John, Beena Mary; Krishna, P. B.; Sruthi, C. T.; Chacko, Maria

    2014-01-28

    Linear light polarizing films selectively transmit radiations vibrating along an electromagnetic radiation vector and selectively absorb radiations vibrating along a second electromagnetic radiation vector. It happens according to the anisotropy of the film . In the present study the polarization effects of methylene blue sensitized polyvinyl alcohol is investigated. The polarization effects on the dye concentration, heating and stretching of film also are evaluated.

  10. Visible light induced photobleaching of methylene blue over melamine-doped TiO2 nanocatalyst

    EPA Science Inventory

    TiO2 doping with N-rich melamine produced a stable, active and visible light sentisized nanocatalyst that showed a remarkable efficiency towards the photobleaching of a model compound – methylene blue (MB) in aqueous solution. The photobleaching followed a mixed reaction order ki...

  11. Citrus pectin derived porous carbons as a superior adsorbent toward removal of methylene blue

    NASA Astrophysics Data System (ADS)

    Zhang, Wenlin; Zhang, Lian Ying; Zhao, Xi Juan; Zhou, Zhiqin

    2016-11-01

    An adsorbent, citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward removal of methylene blue, was synthesized by a facile zinc chloride activation approach in this study. The materials hold a great potential for treatment of dye wastewater.

  12. [Ectopic mediastinal parathyroid tumor resected by video-assisted thoracic surgery with intraoperative methylene blue infusion; report of a case].

    PubMed

    Okagawa, Takehiko; Hiramatsu, Yoshinori

    2014-03-01

    We report a surgical case of ectopic mediastinal parathyroid tumor resected by video-assisted thoracic surgery with intraoperative methylene blue infusion. It is often difficult to detect ectopic mediastinal parathyroid tumor during the operation because the tumor is soft, small and buried under mediastinal tissue. After methylene blue 4 mg/kg intravenously administration, the tumor was gradually dyed blue and easily detected and resected by video-assisted thoracic surgery. It is useful of methylene blue for detection of ectopic mediastinal parathyroid tumor.

  13. [Sensitive determination of Bi3+ by spectrofluorimetry based on graphene oxide-methylene blue system].

    PubMed

    Zhai, Qiu-ge; Guo, Peng; Zhou, Lin; Liu, Yan-ming

    2014-08-01

    Graphene oxide was prepared by the modified Hummers method and characterized by field emission scanning electron microscopy. The interaction of graphene with methylene blue was studied by UV absorption, the intensity of two main absorption peaks of methylene blue decreased significantly after the fluorescence was quenched, and the energy transfer didn't occur because the overlap of the absorption spectrum of GO and the emission spectrum of MB is too small. Therefore, the fluorescence quenching of MB and GO was static. When adding a certain amount of Bi3+ in the graphene-methylene blue system, Bi3+ replaces the methylene blue from the graphene-methylene blue complexes because Bi3+ has the smaller volume and is more positively charged. The methylene blue therefore dissociates from the GO-MB complexes, resulting in the recovery of fluorescence of the system. Furthermore, the fluorescence of the system increases with the increase in the amount of Bi3+ due to the enhanced amount of MB in the system. A novel spectrofluorimetric method was therefore developed for the sensitive determination of Bi3+. Some parameters including the concentration of methylene blue, the amount of graphene oxide, the amount of nitric acid and the sequence of reagent adding were optimized to obtain higher sensitivity. The fluorescence of the system was detected at an emission wavelength of 667 nm with excitation at 690 nm. Under the optimized conditions, the concentration of Bi3+ showed good linear relationships with the fluorescence intensity in the range of 0.5-100 micromol x L(-1), with correlation coefficients of r = 0.9955. The limits of detection for Bi3+ was 1.0 x 10(-8) mol x L(-1) (S/N=3). The selectivity of the proposed method was evaluated and the results showed that 1000-fold K+, Ca+, Na+, Mg2+, Cu2+; 100-fold Fe3+, Be2+, SiO2- Al3+, Ni2+, Sb3+, NO3-, Cl-, F-, and 20-fold Pb2+, Hg2+, Cd2+ had negligible interference with the determination of Bi3+. The method has advantages of

  14. Methylene blue MMX tablets for chromoendoscopy. Safety tolerability and bioavailability in healthy volunteers.

    PubMed

    Repici, A; Di Stefano, A F D; Radicioni, M M; Jas, V; Moro, L; Danese, S

    2012-03-01

    Methylene blue-MMX tablets are proposed as colonic diagnostic staining. Methylene blue taken prior to colonoscopy is expected to provide an effective staining of colonic and rectal mucosa leaving unstained the dysplastic or polypoid areas. The present single dose, open-label study investigated the safety of methylene blue after single oral doses of 200 and 400mg in healthy volunteers. The absolute bioavailability was also investigated after the intake of 2L of bowel cleansing preparation in 2h and by comparing the dose of 200mg with a single iv dose of 100mg in the same subjects. Only non-serious adverse events occurred. Related events occurred to 8/22 subjects. Most of the events were mild and transient. Abnormal transaminases, gastrointestinal disorders and dysuria frequency were 13.6%. After intake of the laxative and the oral dose of 200mg, systemic exposure to methylene blue was shown in all subjects with concentrations increasing for 12h. The peak was reached in a median of 16 h. Peak blood concentration did not increase proportionally with the dose. AUC(0-t) was 32.94 μg/mL × h after 200mg and 38.08 μg/mL × h after 400mg. Half life ranged between 14 and 27 h after the lower dose and between 6 and 26 h after the higher dose. The cumulative excretion was about 40% of the injected dose, 39.67% after 200mg and 23.48% after 400mg. Absolute bioavailability of methylene blue calculated as ratio between AUC(0-t) oral/iv corrected for the dose was on average F(abs)=139.19 ± 52.00%.

  15. Methylene blue increases contralateral testicular ischaemia-reperfusion injury after unilateral testicular torsion.

    PubMed

    Inan, Mustafa; Basaran, Umit N; Dokmeci, Dikmen; Yalcin, Omer; Aydogdu, Nurettin; Turan, Nesrin

    2008-01-01

    1. Testicular ischaemia-reperfusion injury is commonly seen in childhood. Infertility occurs in 25% of patients after unilateral testicular ischaemia. It is has been reported that methylene blue has a positive effect in the reparation of ischaemia-reperfusion injury in different tissues. Therefore, we hypothesized that methylene blue may prevent the hazardous effects of ischaemia-reperfusion injury in testicular tissue after unilateral testicular torsion. 2. Thirty-two prepubertal Wistar-albino rats were divided into four groups. Testicular torsion was created by rotating the right testis 720 degrees in a clockwise direction for 5 h in all groups except for Group C, which was the sham control group. In Group T, bilateral orchiectomy was performed following the torsion period. In Group TD, both testes were removed 5 days after the torsion period. In Group MB, methylene blue (1 mg/kg, i.p.) was administered 40 min before detorsion and once daily over 5 days; then, both testes were harvested. Tissue levels of malondialdehyde (MDA), serum levels of creatine kinase (CK), mean testicular biopsy score (MTBS) and mean seminifer tubule diameter (MSTD) were determined. 3. There was a significant difference in MTBS between Groups T and TD (P < 0.05) in both ipsilateral and contralateral testes. In the contralateral testis, treatment with methylene blue decreased MTBS and MSTD (P < 0.05) and increased MDA levels (P < 0.05). In Group T, mean serum CK concentrations were higher than in any of the other groups (P < 0.05). 4. After 5 h of unilateral testicular torsion and a 5 day reperfusion period, serious tissue damage occurred on both the ipsilateral and contralateral sides. Serum CK concentrations may be an indicator for ischaemia, but not for ischaemia-reperfusion injury. Contrary to our hypothesis, methylene blue increased contralateral testicular damage after unilateral testicular torsion and exacerbated oxidative events.

  16. Stainless steel wire mesh-supported ZnO for the catalytic photodegradation of methylene blue under ultraviolet irradiation.

    PubMed

    Vu, Tan T; del Río, Laura; Valdés-Solís, Teresa; Marbán, Gregorio

    2013-02-15

    The aim of this study was to assess the activity of catalysts formed by nanostructured zinc oxide supported on stainless steel wire mesh for the photocatalytic degradation of methylene blue under UV irradiation. Catalysts prepared by means of different low temperature synthesis methods, as described in a previous work (Vu et al., Mater. Res. Bull. 47 (2012) 1577-1586) were tested. A new activity parameter was introduced in order to compare the catalytic activity of the different catalysts. The best catalyst showed a catalytic activity higher than that of the reference material TiO(2) P25 (Degussa-Evonik). This high activity is attributed to a higher quantum yield derived from the small particle length of the ZnO deposited on the wire mesh. The photocatalytic degradation kinetics of methylene blue fitted a potential model with n orders ranging from 0.5 to 6.9. Reaction orders over 1 were attributed to catalyst deactivation during the reaction resulting from the photocorrosion of ZnO.

  17. [Magnification endoscopy diagnosis of Barrett's esophagus with methylene blue and acetic acid].

    PubMed

    Yagi, Kazuyoshi; Nakamura, Atsuo; Sekine, Atsuo

    2005-08-01

    Intestinal metaplasia of Barrett's esophagus is pre-cancerous lesion and it is important to diagnose intestinal metaplasia by endoscopic examination. Predefined 4 quadrant sampling technique is popular in western countries. However, chromoendoscopy or magnification endoscopy have been tried to diagnose intestinal metaplasia. We have carried out magnification endoscopy with methylene blue and magnification endoscopy with acetic acid. In magnification endoscopy with methylene blue, intestinal metaplasia showed blue-staining area with tubulaous or cavernous pattern. In magnification endoscopy with acetic acid, all of epithelium of Barrett's esophagus changed to whitening surface and it was easy to observe the structure of each epithelium. Intestinal metaplasia showed tubulaous or villous, although fundic type showed pits of small round and cardiac type showed oval pattern with central-slit pits.

  18. Visible-light assisted methylene blue (MB) removal by novel TiO(2)/adsorbent nanocomposites.

    PubMed

    Zhang, Wei; Zou, Linda; Wang, Lianzhou

    2010-01-01

    In present work, visible light sensitive TiO(2)/adsorbent nanocomposites (TNC) were prepared via a facile wet chemical method. Three types of adsorbents including zeolites (F-9, HSZ-690 and HSZ-930), mesoporous silica (MPS-2.7 and 4) and activated carbon, were used as the porous substrates for nanocomposites. Visible light sensitivity was incorporated to TNCs by nitrogen doping of TiO(2), which is obtained through the addition of a nitrogen precursor, triethylamine, within the same wet chemical procedure. The photocatalytic and adsorption ability of as-prepared TNC resultants were studied using solutions of methylene blue (MB) as a model pollutant. Synergistic interactions between adsorption and visible-light photocatalysis were observed, as under the assistance of visible-light irradiation all TNCs achieved higher MB removal rates than those by adsorption process alone. The better performance of the as-prepared N-doped TNC reveals its potential to be used for cost effective solar photocatalytic degradation of dissolved organic compounds.

  19. Decolorization of methylene blue in aqueous suspensions of gold nanoparticles using parallel nanosecond pulsed laser.

    PubMed

    Zong, Yan P; Liu, Xian H; Du, Xi W; Lu, Yi R; Wang, Mei Y; Wang, Guang Y

    2013-01-01

    Using 532 nm parallel nanosecond pulsed laser, the decolorization of methylene blue (MB) in aqueous suspensions of gold nanoparticles (GNPs) was studied. The effects of various experimental parameters, such as irradiation time, laser energy, and initial MB concentration on the decolorization rate were investigated. Experiments using real samples of textile dyeing wastewater were also carried out to examine the effectiveness of the method in more complex samples. From the results, the following conclusions may be drawn: (i) Under the optimum conditions (pH 7.19, 135 mJ laser energy, 4 mg/L MB concentration, and 11.6 mg/L GNP concentration), the rate of MB decolorization could reach 94% in 15 min. The decolorization follows pseudo-first-order kinetics; (ii) The amount of MB decreased rapidly during the decolorization. No intermediates of the decolorization could be detected by high-performance liquid chromatography. These observations indicate that MB was decolorized through a very rapid degradation mechanism; (iii) The rate of MB decolorization increased with the increase in laser energy (at laser energies of 0 to 135 mJ); and, (iv) The efficient decolorization of MB in real samples of textile dyeing wastewater was achieved at a decolorization rate of about 85% in 15 min.

  20. Decolorization of Methylene Blue by Persulfate Activated with FeO Magnetic Particles.

    PubMed

    Hung, Chang-Mao; Chen, Chiu-Wen; Liu, Yi-Yuan; Dong, Cheng-Di

    2016-08-01

    In this study, the degradation of methylene blue (MB) was conducted to evaluate the feasibility of using persulfate oxidation activated with iron oxide (FeO) magnetic particles. The results demonstrated that the decolorization rate of MB increased with increasing FeO concentration, exhibiting maximum efficiency at pH0 3.0. The kinetics of MB was studied in the binary FeO catalyst and persulfate oxidation system. The surface properties of FeO before and after reaction was analyzed using cyclic voltammogram (CV), three-dimensional excitation-emission fluorescence matrix (EEFM) spectroscopy, zeta potential, particle size distribution measurements, X-ray diffraction (XRD) and environmental scanning electron microscopy-energy dispersive X-ray spectrometry (ESEM-EDS). The CV data indicated that a reversible redox reaction holds the key to explaining the significant activity of the catalyst. EEFM was used to evaluate the catalyst yield of FeO by fluorescence intensity plots with excitation/emission at 220/300 nm and 260/300 nm. The XRD and ESEM-EDS results confirmed the presence of FeO in the catalyst.

  1. Decolorization of methylene blue in layered manganese oxide suspension with H2O2.

    PubMed

    Zhang, Lili; Nie, Yulun; Hu, Chun; Hu, Xuexiang

    2011-06-15

    Layered birnessite-type manganese oxides (Na-OL-1) were prepared via a redox reaction involving MnO(4)(-) and Mn(2+) under markedly alkaline conditions. According to the XRD analysis, the resulting material exhibited a well-crystallized octahedral layer (OL) structure with several different phases, including β-MnOOH, α-MnOOH and γ-Mn(3)O(4). The catalyst was highly effective for the decolorization and degradation of methylene blue (MB) in the presence of H(2)O(2) at neutral pH. The tested MB was completely decolorized in Na-OL-1 suspension by the fraction dosing of H(2)O(2) (556.5mM at the beginning and then 183.8mM at 40 min). Based on the studies of electron spin resonance and the effect of radical scavengers, the (1)O(2) and O(2)(-) were the main reactive oxygen species (ROS) in the reaction. It was found that both oxygen and ROS were generated from the decomposition of H(2)O(2) in Na-OL-1 suspension, wherein the decomposition pathways were proposed. The generation of H(2)O(2) in Na-OL-1 suspension at air atmosphere indicated that the existence of multivalent manganese oxides greatly enhanced the interfacial electron transfer, leading to the high activity of Na-OL-1.

  2. Graphene oxide functionalized with methylene blue and its performance in singlet oxygen generation

    SciTech Connect

    Wojtoniszak, M.; Rogińska, D.; Machaliński, B.; Drozdzik, M.; Mijowska, E.

    2013-07-15

    Graphical abstract: - Highlights: • Adsorption of methylene blue (MB) on graphene oxide (GO). • Characterization of graphene oxide–methylene blue nanocomposite (MB–GO). • Examination of MB–GO efficiency in singlet oxygen generation (SOG). • MB–GO performs higher SOG efficiency than pristine MB. - Abstract: Due to unique electronic, mechanical, optical and structural properties, graphene has shown promising applications in many fields, including biomedicine. One of them is noninvasive anticancer therapy – photodynamic therapy (PDT), where singlet oxygen (SO), generated under the irradiation of light with appropriate wavelengths, kills cancer cells. In this study, authors report graphene oxide (GO) noncovalent functionalization with methylene blue (MB). MB molecules underwent adsorption on the surface of GO. Detailed characterization of the obtained material was carried out with UV–vis spectroscopy, Raman spectroscopy, FT-IR spectroscopy, and confocal laser scanning microscopy. Furthermore, its performance in singlet oxygen generation (SOG) under irradiation of laser with excitation wavelengths of 785 nm was investigated. Interestingly, GO functionalized with MB (MB–GO) showed enhanced efficiency in singlet oxygen generation compared to pristine MB. The efficiency in SOG was detected by photobleaching of 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABMDMA). These results indicate the material is promising in PDT anticancer therapy and further in vitro and in vivo studies are required.

  3. Methylene blue induces macroautophagy through 5' adenosine monophosphate-activated protein kinase pathway to protect neurons from serum deprivation.

    PubMed

    Xie, Luokun; Li, Wenjun; Winters, Ali; Yuan, Fang; Jin, Kunlin; Yang, Shaohua

    2013-01-01

    Methylene blue has been shown to be neuroprotective in multiple experimental neurodegenerative disease models. However, the mechanisms underlying the neuroprotective effects have not been fully elucidated. Previous studies have shown that macroautophagy has multiple beneficial roles for maintaining normal cellular homeostasis and that induction of macroautophagy after myocardial ischemia is protective. In the present study we demonstrated that methylene blue could protect HT22 hippocampal cell death induced by serum deprivation, companied by induction of macroautophagy. We also found that methylene blue-mediated neuroprotection was abolished by macroautophagy inhibition. Interestingly, 5' adenosine monophosphate-activated protein kinase (AMPK) signaling, but not inhibition of mammalian target of rapamycin signaling, was activated at 12 and 24 h after methylene blue treatment in a dose-dependent manner. Methylene blue-induced macroautophagy was blocked by AMPK inhibitor. Consistent with in vitro data, macroautophagy was induced in the cortex and hippocampus of mouse brains treated with methylene blue. Our findings suggest that methylene blue-induced neuroprotection is mediated, at least in part, by macroautophagy though activation of AMPK signaling.

  4. Differential photodynamic response of cultured cells to methylene blue and toluidine blue: role of dark redox processes.

    PubMed

    Blázquez-Castro, Alfonso; Stockert, Juan C; Sanz-Rodríguez, Francisco; Zamarrón, Alicia; Juarranz, Angeles

    2009-03-01

    Cultured cells treated with equal concentrations of thiazine photosensitizers methylene blue (MB) or toluidine blue (TB) showed a distinct photodynamic lethality, with TB being much more effective, when exposed to red light from a LED source. This effect is accounted for because of the differences in the chemical reduction of MB and TB in the intracellular environment. While TB accumulates as blue granular structures, MB does not give such a localization pattern. However, upon exposure of MB-treated cells to oxidant agents, the dye becomes clearly localized in the cytoplasm as blue granules. We propose that massive reduction of MB to its leuco form inside the cell inhibits most of the photodynamic damage, while no such reduction occurs with TB.

  5. Fast-response humidity-sensing films based on methylene blue aggregates formed on nanoporous semiconductor films

    NASA Astrophysics Data System (ADS)

    Ishizaki, Ryota; Katoh, Ryuzi

    2016-05-01

    We prepared fast-response colorimetric humidity-sensing (vapochromic) films based on methylene blue adsorption onto nanoporous semiconductor (TiO2, Al2O3) films. Color changes caused by changes of humidity could be easily identified visually. A characteristic feature of the vapochromic films was their fast response to changes of humidity. We found that the response began to occur within 10 ms. The response was rapid because all the methylene blue molecules attached to the nanoporous semiconductor surface were directly exposed to the environment. We also deduced that the color changes were caused by structural changes of the methylene blue aggregates on the surface.

  6. [Methylene blue test for the determination of viability of free larvae of Trichinella spiralis].

    PubMed

    Randazzo, V R; Costamagna, S R

    2010-01-01

    The present research was carried out with the purpose of determining whether or not the methylene blue test could also evidence viability of free larvae of Trichinella spiralis, taking into account its usefulness in the determination of viability of protoscolices in Echinococcus granulosus. To this end, three T. spiralis larval suspensions (M1, M2 and M3) were used, each containing 500 free larval stages. A hundred microl of methylene blue solution 1:10000 in distilled water were added to 100 microl of the larval suspension. Larvae were observed under optical microscopy to evaluate motility. M1 was exposed to -30 degrees C and could be observed on day 70, M2 was exposed to 80 degrees C during 5 minutes and it was immediately observed under optical microscopy, and M3 was maintained at 4 degrees C during the experiment as a 100% viability testing. Our results indicated that when T. spiralis larvae took up 100% of the methylene blue stain (M1 and M2), their inner structures appeared not only retracted but also stained blue, whereas in the M3 suspension test, larvae remained unstained and 100% of them showed their typical spiral-like movement.

  7. Adsorption of methylene blue using Fe3O4/CuO/ZnO/ nanographene platelets (NGP) composites with various NGP concentration

    NASA Astrophysics Data System (ADS)

    Tju, H.; Taufik, A.; Saleh, R.

    2016-11-01

    This study will examine the use of Fe3O4/CuO/ZnO nanocomposites that have been modified by Nanographene Platelets (NGP) as an adsorbent to degrade organic dye waste Methylene Blue (MB). The nanocomposites were synthesized using the sol-gel method then combined with three variatons of NGP weight percents by simple hydrothermal method. The Fe3O4/CuO/ZnO/NGP composites were characterized using the X-Ray Diffraction (XRD) spectroscopy, Fourier Transform Infrared (FTIR), Energy Dispersive X-Ray (EDX), Thermogravimetric Analysis (TGA) and Vibrating Sample Magnetometer (VSM). The composites exhibit ferromagnetic behaviour. The presence of hexagonal wurtzite of ZnO, monoclinic of CuO and cubic spinel of Fe3O4 were found in the composites. The graphitic-like structure represents the presence of the NGP in the composites. However, the addition of NGP weight percent reduces the thermal stability of the composites. The adsorption capability of the composites are analyzed by observing the degradation of organic dye Methylene Blue (MB) under dark condition. The NGP addition of 15 wt% show the best result of the composites to degrade Methylene Blue in alkaline condition. Adsorption mechanism of the composites with NGP addition tend to follow the model Langmuir adsorption kinetic models.

  8. Methylene-blue aided rapid confocal laser endomicroscopy of breast cancer

    NASA Astrophysics Data System (ADS)

    Vyas, Khushi; Hughes, Michael; Leff, Daniel Richard; Yang, Guang-Zhong

    2017-02-01

    Breast conserving surgery allows complete tumor resection while maintaining acceptable cosmesis for patients. Safe and rapid intraoperative margin assessment during the procedure is important to establish the completeness of tumor excision and minimizes the need for reoperation. Confocal laser endomicroscopy has demonstrated promise for real-time intraoperative margin assessment using acriflavine staining, but it is not approved for routine in-human use. We describe a custom high-speed line-scan confocal laser endomicroscopy (LS-CLE) system at 660 nm that enables high-resolution histomorphological imaging of breast tissue stained with methylene-blue, an alternative fluorescent stain for localizing sentinel nodes during breast surgery. Preliminary imaging results on freshly excised human breast tissue specimens are presented, demonstrating the potential of methylene-blue aided rapid LS-CLE to determine the oncological status of surgical margins in-vivo.

  9. Comparative study of calcium alginate, activated carbon, and their composite beads on methylene blue adsorption.

    PubMed

    Hassan, A F; Abdel-Mohsen, A M; Fouda, Moustafa M G

    2014-02-15

    Three adsorbents, calcium alginate beads (AB), sodium hydroxide activated carbon based coconut shells (C), and calcium alginate/activated carbon composite beads (ACB) were prepared. Their textural properties were characterized by N2-adsorption at -196°C and scanning electron microscopy. The porosity, surface area and total pore volume of C>ACB>AB, but AB adsorbent was more acidic function groups more than the other adsorbents. Adsorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature and initial concentration of methylene blue. Methylene blue adsorption on C, AB and ACB was observed at pH>6 to avoid the competition of H(+). The amount of dye adsorbed increases as the adsorbent dosage increase. Adsorption of dye follows pseudo-second order mechanism. Thermodynamic studies show spontaneous and endothermic nature of the overall adsorption process.

  10. Methylene blue intercalated into calcium phosphate - Electrochemical properties and an ascorbic acid oxidation study

    NASA Astrophysics Data System (ADS)

    Lazarin, Angélica M.; Airoldi, Claudio

    2008-09-01

    Methylene blue (MB) was intercalated inside the cavity of a layered calcium phosphate host. The dye is strongly retained and not easily leached from the matrix. The intercalated dye material was incorporated into a carbon paste electrode and by means of cyclic voltammetry and amperometry, its electrochemical properties were investigated. In various electrolyte solutions, on changing the pH between 3 and 9, the midpoint potential remained practically constant at -0.15 V. This is not the usual behavior for MB, since it is known that in the solution phase the midpoint potential changes considerably with pH, indicating that, in the present case, methylene blue is a guest molecule intercalated inside the lamellar structure of the calcium phosphate. An electrode made with this material was used to study the electrochemical oxidation of ascorbic acid and then applied to commercial samples, with excellent agreement within the 95% confidence level.

  11. An evaluation of the effect of methylene blue dye pH on apical leakage.

    PubMed

    Starkey, D L; Anderson, R W; Pashley, D H

    1993-09-01

    The effect of varying the pH of 2% methylene blue dye on apical leakage was evaluated. Eighty-four roots of extracted human teeth were used in this study. The roots were endodontically cleaned and shaped, obturated, apically resected, and amalgam or Temporary Endodontic Restorative Material retro-fillings were placed. The roots were immersed for 7 days in dye solutions of controlled pH of 1, 2, 3, 5 or 7, or in a 2% unbuffered deionized water solution of methylene blue. The results demonstrated significantly less leakage in the pH 1 and 2 amalgam groups. All other amalgam groups and the Temporary Endodontic Restorative Material groups showed no significant differences attributable to pH. Temporary Endodontic Restorative Material retrofilling groups demonstrated statistically significantly less apical leakage at each pH evaluated than the amalgam-retrofilled groups. Additionally, a significant buffering effect of the root structure on the dye solutions was measured.

  12. Photodynamic action of laser radiation and methylene blue on some opportunistic microorganisms of the oral cavity

    NASA Astrophysics Data System (ADS)

    Ivanov, Krill I.; Titorenko, Vladimir A.; Shoub, Gennady M.; Lepilin, Alexander V.; Ovchinnikov, Ilya S.; Mischenko, Oksana S.; Tuchin, Valery V.

    2000-03-01

    We have studied photodynamic action of He-Ne laser radiation on cultures of Staphylococcus (strain 209 P), Streptococcus anhaemolyticus, and total microflora of dental deposit been sensitized by methylene blue. The concentration of the dye was varied from 0.001% to 0.1%, radiation power density was 100 mW/cm2. Irradiated strain was put into thermostat for 24 hours, then the number of colonies was counted and analyzed.

  13. Methylene blue removal from contaminated waters using heterogeneous catalytic ozonation promoted by natural zeolite: mechanism and kinetic approach.

    PubMed

    Valdés, H; Tardón, R F; Zaror, C A

    2012-09-01

    This paper presents experimental results of a methylene blue removal system based on heterogeneous catalytic ozonation in the presence of natural zeolite. The effect of pH (2-10) and the presence of radical scavengers (acetate ions) on homogeneous and heterogeneous ozonation systems are assessed at laboratory scale. Results show that heterogeneous catalytic ozonation using natural zeolite increases methylene blue removal rate with respect to the single ozonation process at all pH values. The inhibitory effect of free-radical scavengers is impaired by zeolite, suggesting that methylene blue oxidation reactions take place mainly on the zeolite surface. The increase in methylene blue removal rate could be related to ozone interaction with hydroxyl groups present on the zeolite surface (S--OH2(+), S--OH, S--O(-)), which plays a key role in the reaction mechanism.

  14. Electrochemical preparation of poly(methylene blue)/graphene nanocomposite thin films

    SciTech Connect

    Erçarıkcı, Elif; Dağcı, Kader; Topçu, Ezgi; Alanyalıoğlu, Murat

    2014-07-01

    Highlights: • Poly(MB)/graphene thin films are prepared by a simple electrochemical approach. • Graphene layers in the film show a broad band in visible region of absorbance spectra. • Morphology of composite films indicates both disordered and ordered regions. • XRD reveals that nanocomposite films include rGO layers after electropolymerization process. • Chemically prepared graphene is better than electrochemically prepared graphene for electrooxidation of nitrite. - Abstract: Poly(methylene blue)/graphene nanocomposite thin films were prepared by electropolymerization of methylene blue in the presence of graphene which have been synthesized by two different methods of a chemical oxidation process and an electrochemical approach. Synthesized nanocomposite thin films were characterized by using cyclic voltammetry, UV–vis. absorption spectroscopy, powder X-ray diffraction, and scanning tunneling microscopy techniques. Electrocatalytical properties of prepared poly(methylene blue)/graphene nanocomposite films were compared toward electrochemical oxidation of nitrite. Under optimized conditions, electrocatalytical effect of nanocomposite films of chemically prepared graphene through electrochemical oxidation of nitrite was better than that of electrochemically prepared graphene.

  15. Impact of methylene blue in addition to norepinephrine on the intestinal microcirculation in experimental septic shock.

    PubMed

    Nantais, Jordan; Dumbarton, Tristan C; Farah, Nizam; Maxan, Alexander; Zhou, Juan; Minor, Samuel; Lehmann, Christian

    2014-01-01

    Methylene blue (MB) has been used with some success as a treatment for the vasoplegia of vasopressor-refractory septic shock. The putative mechanism of action of MB is the inhibition of endothelial nitric oxide within the microvasculature and improved responsiveness to endogenous catecholamines (norepinephrine (NE)). However, to date, no study has demonstrated the microcirculatory effect of methylene blue in septic shock. The objective of this randomized, controlled, animal study was to show, in an experimentally-induced, septic shock model in rats, the effects of MB and NE on global hemodynamics and the microcirculation. Mean arterial pressure (MAP) was drastically reduced following bacterial endotoxin (lipopolysaccharide, LPS) administration in animals not receiving vasopressors. Only the combination of NE + MB restored MAP to control levels by the end of the three hour experiment. Intravital microscopy of the microcirculation was performed in the terminal ileum in order to examine functional capillary density in intestinal muscle layers and the mucosa, as well as leukocyte activation in venules (rolling, adhesion to the endothelium). Untreated LPS animals showed a significant increase in leukocyte adhesion and a decrease in capillary perfusion in the intestinal microcirculation. In groups receiving NE or NE+MB, we observed a significant decrease in leukocyte adhesion and improved functional capillary density, indicating that microvasculature function was improved. This study suggests that methylene blue may be able to improve hemodynamics while preserving microvascular function in septic shock.

  16. 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: CuSO4 (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 > CuSO4 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.

  17. Comparison of acridine orange, methylene blue, and Gram stains for blood cultures.

    PubMed Central

    Mirrett, S; Lauer, B A; Miller, G A; Reller, L B

    1982-01-01

    Direct microscopic screening of blood cultures by Gram stain or methylene blue stain is time consuming and frequently insensitive. Therefore, we evaluated a fluorescent-staining procedure that uses acridine orange (AO) at pH 3.5 and compared it with the methylene blue and Gram stain procedures. All smears were prepared within 24 h of receiving the culture, fixed with methanol, and examined without the results of the companion smears being known. AO-stained smears were examined with incident-light fluorescence at 600 x magnification and confirmed at 1,500x magnification. All bottles macroscopically positive within 24 h were excluded from the study. Of 2,946 cultures entered into the study, 204 (6.9%) were positive within 3 days. The sensitivity and specificity of AO based on these culture results were 52 and 98%, respectively, compared with 38% sensitivity and 99% specificity by methylene blue and Gram stains. The AO staining procedure is a simple, sensitive, screening technique for the early detection of positive blood cultures. PMID:6175656

  18. Alternative mitochondrial electron transfer for the treatment of neurodegenerative diseases and cancers: Methylene blue connects the dots.

    PubMed

    Yang, Shao-Hua; Li, Wenjun; Sumien, Nathalie; Forster, Michael; Simpkins, James W; Liu, Ran

    2015-11-18

    Brain has exceptional high requirement for energy metabolism with glucose as the exclusive energy source. Decrease of brain energy metabolism and glucose uptake has been found in patients of Alzheimer's, Parkinson's and other neurodegenerative diseases, providing a clear link between neurodegenerative disorders and energy metabolism. On the other hand, cancers, including glioblastoma, have increased glucose uptake and rely on aerobic glycolysis for energy metabolism. The switch of high efficient oxidative phosphorylation to low efficient aerobic glycolysis pathway (Warburg effect) provides macromolecule for biosynthesis and proliferation. Current research indicates that methylene blue, a century old drug, can receive electron from NADH in the presence of complex I and donates it to cytochrome c, providing an alternative electron transfer pathway. Methylene blue increases oxygen consumption, decrease glycolysis, and increases glucose uptake in vitro. Methylene blue enhances glucose uptake and regional cerebral blood flow in rats upon acute treatment. In addition, methylene blue provides protective effect in neuron and astrocyte against various insults in vitro and in rodent models of Alzheimer's, Parkinson's, and Huntington's disease. In glioblastoma cells, methylene blue reverses Warburg effect by enhancing mitochondrial oxidative phosphorylation, arrests glioma cell cycle at s-phase, and inhibits glioma cell proliferation. Accordingly, methylene blue activates AMP-activated protein kinase, inhibits downstream acetyl-coA carboxylase and cyclin-dependent kinases. In summary, there is accumulating evidence providing a proof of concept that enhancement of mitochondrial oxidative phosphorylation via alternative mitochondrial electron transfer may offer protective action against neurodegenerative diseases and inhibit cancers proliferation.

  19. Activated electric arc furnace slag as an effective and reusable Fenton-like catalyst for the photodegradation of methylene blue and acid blue 29.

    PubMed

    Nasuha, N; Ismail, S; Hameed, B H

    2017-03-14

    In this work, an activated electric arc furnace slag (A-EAFS) was investigated as an effective Fenton catalyst for the photodegradation of methylene blue (MB) and acid blue 29 (AB29). Fourier transform infrared spectroscopy and UV-visible absorption analyses indicated that A-EAFS offers additional Fe3O4 because of the changes in the iron oxide phase and the favorable response to visible light. It has been found that the highest degradation efficiency can reach up to 94% for MB under optimal conditions of 1 g L(-1) of A-EAFS, 20 mM H2O2, and pH 3. The optimal conditions for AB29 were 0.1 g L(-1) A-EAFS, 4 mM H2O2, and pH 3 to reach 98% degradation efficiency. Visible light enhanced the degradation of both dyes. In addition, A-EAFS, could be easily separated magnetically, exhibited good chemical stability after seven successive photodegradation cycles.

  20. Functional Polymeric Systems as Delivery Vehicles for Methylene Blue in Photodynamic Therapy.

    PubMed

    Junqueira, Mariana V; Borghi-Pangoni, Fernanda B; Ferreira, Sabrina B S; Rabello, Bruno R; Hioka, Noboru; Bruschi, Marcos L

    2016-01-12

    Antibiotic-resistant microorganisms have become a global concern, and the search for alternative therapies is very important. Photodynamic therapy (PDT) consists of the use of a nontoxic photosensitizer (PS), light, and oxygen. This combination produces reactive oxygen species and singlet oxygen, which can alter cellular structures. Methylene blue (MB) is a substance from the phenothiazine class often used as a PS. In this work, to facilitate the PS contact within the wounds, we have used Design of Experiments 2(3) plus central point to develop functional polymeric systems. The formulations were composed by poloxamer 407 [15.0, 17.5, or 20.0% (w/w)], Carbopol 934P [0.15, 0.20, or 0.25% (w/w)], and MB [0.25, 0.50, or 0.75% (w/w)]. The sol-gel transition temperature, flow rheometry, in vitro MB release, and ex vivo study of MB cutaneous permeation and retention were investigated. Moreover, the evaluation of photodynamic activity was also analyzed by in vitro degradation of tryptophan by singlet oxygen and using Artemia salina. The determination of the gelation temperature displayed values within the range of 25-37 °C, and the systems with better characteristics were subjected to rheological analysis and in vitro release profiling. The 20/0.15/0.25 formulation showed the best release profile (42.57% at 24 h). This system displayed no significant skin permeation (0.38% at 24 h), and the photooxidation of tryptophan test showed the production of reactive species of oxygen. The toxicity test using A. salina revealed that the MB associated with the light increased the mortality rate by 61.29%. Therefore, investigating the PDT efficacy of the functional polymeric system containing MB will be necessary in the future.

  1. Preparation and characterization of double layer thin films ZnO/ZnO:Ag for methylene blue photodegradation

    SciTech Connect

    Wibowo, Singgih Sutanto, Heri

    2016-02-08

    Double layer (DL) thin films of zinc oxide and silver-doped zinc oxide (ZnO/ZnO:Ag) were deposited on glass substrate by sol-gel spray coating technique. The prepared thin films were subjected for optical and photocatalytic studies. UV-visible transmission spectra shows that the subtitution of Ag in ZnO leads to band gap reduction. The influence of Ag doping on the photocatalytic activity of ZnO for the degradation of methylene blue dye was studied under solar radiation. The light absorption over an extended visible region by Ag ion doping in ZnO film contributed equally to improve the photocatalytic activity up to 98.29%.

  2. Preparation and characterization of double layer thin films ZnO/ZnO:Ag for methylene blue photodegradation

    NASA Astrophysics Data System (ADS)

    Wibowo, Singgih; Sutanto, Heri

    2016-02-01

    Double layer (DL) thin films of zinc oxide and silver-doped zinc oxide (ZnO/ZnO:Ag) were deposited on glass substrate by sol-gel spray coating technique. The prepared thin films were subjected for optical and photocatalytic studies. UV-visible transmission spectra shows that the subtitution of Ag in ZnO leads to band gap reduction. The influence of Ag doping on the photocatalytic activity of ZnO for the degradation of methylene blue dye was studied under solar radiation. The light absorption over an extended visible region by Ag ion doping in ZnO film contributed equally to improve the photocatalytic activity up to 98.29%.

  3. Heterogeneous photo-Fenton decolorization of methylene blue over LiFe(WO4)2 catalyst.

    PubMed

    Ji, Fei; Li, Chaolin; Zhang, Jiahuan; Deng, Lei

    2011-02-28

    Heterogeneous photo-Fenton process using LiFe(WO(4))(2) as catalyst was studied to degrade Methylene blue (MB) dye in aqueous solution. The results indicated that LiFe(WO(4))(2) could effectively catalyze the decolorization of MB in the presence of UV light and H(2)O(2). The effects of different parameters such as amounts of catalyst, H(2)O(2) concentration, initial pH of the dye solution, initial dye concentration and UV light intensity on the decolorization efficiency of the process were investigated. It was found that LiFe(WO(4))(2) possessed a wide applicable pH range. X-ray photoelectron spectroscopy (XPS) was applied to investigate the transformation between Fe(III) and Fe(II). It was also observed that catalytic behavior could be reproduced in consecutive experiments without a considerable drop in the process efficiency.

  4. One-pot synthesis of MnO2-chitin hybrids for effective removal of methylene blue.

    PubMed

    Dassanayake, Rohan S; Rajakaruna, Erandathi; Moussa, Hanna; Abidi, Noureddine

    2016-12-01

    Manganese dioxide (MnO2)-chitin-hybrid material was prepared by a facile "one-pot" synthesis method. MnO2-chitin hybrid was used for the effective removal of methylene blue (MB) from liquid solution as model for wastewater treatment. The hybrid obtained was characterized by field emission scanning electron microscopy and energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. The effect of pH and temperature were studied. MnO2-chitin hybrid showed high performance for oxidative decolorization and removal of MB. Typically, 25mL of MB (20mg/L) can be completely decolorized in 2.5min with 8.5mg of the MnO2-chitin hybrid. The hybrid material exhibited excellent recyclability and durability with the degradation value of 99% for MB after ten consecutive cycles.

  5. Novel methylene blue staining technique for localizing small esophageal leiomyomas during thoracoscopic enucleation.

    PubMed

    Zhang, Z; Ai, B; Liao, Y; Liu, L; Liu, M

    2016-11-01

    The treatment of choice for leiomyoma, the most common benign esophageal tumor, is thoracoscopic enucleation. One of the most difficult aspects of thoracoscopic enucleation is the precise localization of small tumors (≤1.5 cm) and tumors without external protrusion. No simple, feasible solutions to this problem are available. We developed a novel methylene blue staining technique to localize small esophageal leiomyomas and evaluated the feasibility of our technique. Between January 2013 and July 2014, eight patients with small esophageal leiomyomas (≤1.5 cm) underwent thoracoscopic enucleation in Tongji Hospital. Preoperative endoscopic ultrasonography was performed in all patients. The leiomyomas were located in the middle (n = 5) and lower (n = 3) thirds of the esophagus. We preoperatively injected 0.5-1.0 mL methylene blue in the submucosa adjacent to the tumors under standard gastroscope guidance. The entire staining process took about 10 minutes. Staining was successful in all patients. The unstained tumor was exposed after the blue-stained mediastinal pleura, and overlying muscle were incised longitudinally. All procedures were successfully completed without conversion to open surgery. No abnormalities were detected in the esophageal mucosa. The median operating time was 60 minutes (range, 40-90 minutes). Postoperative histopathology confirmed leiomyoma in all patients. The median postoperative hospital stay was 6 days (range, 5-7 days). No major complications, such as esophageal leakage or esophageal diverticulum, occurred. Endoscopic methylene blue staining is safe and feasible for localizing small esophageal leiomyomas during thoracoscopic enucleation. This method will enable precise and easy enucleation.

  6. Disproportionation of semimethylene blue and oxidation of leucomethylene blue by methylene blue and by Fe(III). Kinetics, equilibria, and medium effects

    SciTech Connect

    Hay, D.W.; Martin, S.A.; Ray, S.; Lichtin, N.N.

    1981-05-28

    The dependence on reaction medium of the kinetics of three ground-state elementary reactions occurring in the iron-methylene blue photoredox system has been investigated by studying the relaxation of the photostationary state and by flash photolysis. The rate constants which have been evaluated include 2k/sub 6/, for disproportionation of semimethylene blue (S), k/sub -6/, for syn proportionation (the oxidation of leucomethylene blue (L) by methylene blue (MB)), and k/sub 10/, for the oxidation of leucomethylene blue by ferric ion. Variations of media include nature of the solvent and anions, ionic strength, and concentration of acid. Values of the equilibrium constant K/sub 6/ = k/sub -6/2k/sub 6/ = (S)/sup 2//(L)(MB) have been derived from the kinetic data and used in conjunction with potentiometric data to determine values of the one-electron standard reduction potentials, epsilon/sup o'//sub MB/S/ and epsilon/sup o'//sub S/L/ in several media. As in the iron-thionine photoredox system, the half-reduced dye, S, is a minor component of the photostationary state and oxidation of leuco dye by ferric ion appears to proceed via a metastable association complex of the reactants. Mechanistic interpretations of some of the medium effects are suggested.

  7. Equilibrium, kinetics, mechanism, and process design for the sorption of methylene blue onto rice husk.

    PubMed

    Vadivelan, V; Kumar, K Vasanth

    2005-06-01

    Batch experiments were carried out for the sorption of methylene blue onto rice husk particles. The operating variables studied were initial solution pH, initial dye concentration, adsorbent concentration, and contact time. Equilibrium data were fitted to the Freundlich and Langmuir isotherm equations and the equilibrium data were found to be well represented by the Langmuir isotherm equation. The monolayer sorption capacity of rice husks for methylene blue sorption was found to be 40.5833 mg/g at room temperature (32 degrees C). The sorption was analyzed using pseudo-first-order and pseudo-second-order kinetic models and the sorption kinetics was found to follow a pseudo-second-order kinetic model. Also the applicability of pseudo second order in modeling the kinetic data was also discussed. The sorption process was found to be controlled by both surface and pore diffusion with surface diffusion at the earlier stages followed by pore diffusion at the later stages. The average external mass transfer coefficient and intraparticle diffusion coefficient was found to be 0.01133 min(-1) and 0.695358 mg/g min0.5. Analysis of sorption data using a Boyd plot confirms that external mass transfer is the rate limiting step in the sorption process. The effective diffusion coefficient, Di was calculated using the Boyd constant and was found to be 5.05 x 10(-04) cm2/s for an initial dye concentration of 50 mg/L. A single-stage batch-adsorber design of the adsorption of methylene blue onto rice husk has been studied based on the Langmuir isotherm equation.

  8. Novel alkylimidazolium/vanadium pentoxide intercalation compounds with excellent adsorption performance for methylene blue

    SciTech Connect

    Kong Aiguo; Ding Yongjie; Wang Ping; Zhang Hengqiang; Yang Fan; Shan Yongkui

    2011-02-15

    Novel alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds were synthesized by a redox reaction between iodide ion and V{sub 2}O{sub 5}. The X-ray photoelectron spectroscopy and the diffuse reflectance UV-vis spectrometry experiments reveal that the vanadium in the intercalated V{sub 2}O{sub 5} products was partially reduced by an iodide ion and the resultant iodine can be removed in the final products. The transmission electron microscope observation and X-ray diffraction analysis testify that the prepared alkylimidazolium/V{sub 2}O{sub 5} intercalation compounds have typical lamellar structure with different d{sub 100} interlayer spacing values and the special straw-like nanofiber morphology with the length of 0.5-10 {mu}m. Systematic investigation indicates that new intercalation compounds possess the extraordinary adsorption performance for methylene blue in an aqueous solution. -- Graphical abstract: The alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds with special straw-like nanofiber morphology were synthesized by a redox reaction between iodide ion and V{sub 2}O{sub 5}, which show the excellent adsorption performance for methylene blue in an aqueous medium. Display Omitted Research highlights: {yields} Novel alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds. {yields} A simple preparation method by a redox reaction between iodide ion in ionic liquid and V{sub 2}O{sub 5}. {yields} The excellent adsorption performance for methylene blue in an aqueous medium.

  9. Adsorption of methylene blue dye from aqueous solutions using Eichhornia crassipes.

    PubMed

    Wanyonyi, Wycliffe Chisutia; Onyari, John Mmari; Shiundu, Paul Mwanza

    2013-09-01

    Adsorption of methylene blue (MB) from aqueous solution using dried roots, stems, and leaves of Eichhornia crassipes biomass obtained from Lake Victoria was studied. Batch experimental results revealed that the adsorption process was highly dependent on adsorbent dosage, initial MB concentration, E. crassipes particle size and aqueous solution temperature. The isotherm data fitted Freundlich mathematical models with maximum dye adsorption of 35.37 mg g(-1). Roots adsorbed over 99 % of the MB in <5 min. Sorption kinetics followed a pseudo-second-order model. Results provide evidence that E. crassipes is an effective and inexpensive biomaterial for dye removal from aqueous dye solutions and industrial effluents.

  10. Mechanism of complexation of the phenothiazine dye methylene blue with fullerene C60

    NASA Astrophysics Data System (ADS)

    Buchelnikov, A. S.; Kostyukov, V. V.; Yevstigneev, M. P.; Prylutskyy, Yu. I.

    2013-04-01

    The complexation of fullerene C60 with the aromatic dye methylene blue (MB) in aqueous solution was studied. Spectrophotometric titration revealed a reasonably strong interaction between C60 and MB molecules with an equilibrium constant K = 2110 L/mol and the binding of up to five dye molecules with the surface of C60. The energy analysis of the MB-C60 system showed that the intermolecular and hydrophobic interactions were dominant in the energy profile of the complexation, and while the electrostatic factor played an insignificant role.

  11. Methylene blue administration in severe systemic inflammatory response syndrome (SIRS) after thoracic surgery.

    PubMed

    Friedrich, Martin; Bräuer, Anselm; Tirilomis, Theo; Lotfi, Shahram; Mielck, Frank; Busch, Thomas

    2002-10-01

    A 66-year-old male patient developed significant pleural effusion on the right side six years after coronary bypass grafting and mitral valve replacement. After pleurocentesis, hemo-pneumothorax developed and finally resulted in complete atelectasis of the right lung. Three weeks later, the patient was transferred to our department, and underwent a right lateral thoracotomy. The hematoma was removed and a complete decortication was performed. Four hours postoperatively the patient developed severe SIRS with beginning multiorgan failure. Even extremely high doses of norepinephrine could not raise the systemic vascular resistance. Single intravenous administration of methylene blue lead to significant and permanent improvement of the hemodynamic status.

  12. Adsorption Capability of Cationic Dyes (Methylene Blue and Crystal Violet) onto Poly-γ-glutamic Acid.

    PubMed

    Ogata, Fumihiko; Nagai, Noriaki; Kawasaki, Naohito

    2017-01-01

    In this study, the adsorption capability of cationic dyes, which were methylene blue and crystal violet, by poly-γ-glutamic acid (PGA) in a single or binary solution system was investigated. The effect of the molecular weight of PGA, initial dye concentration, solution pH, and temperature on the adsorption of dyes was evaluated. The adsorption mechanism of dyes onto PGA was the interaction between -COOH group on the PGA surface and the polarity groups of dyes. These results indicated that PGA is useful for removal of dyes and cationic organic compounds from a single or binary solution system.

  13. Electrochemical Interrogation of Interactions between Surface-Confined DNA and Methylene Blue

    PubMed Central

    Pan, Dun; Zuo, Xiaolei; Wan, Ying; Wang, Lihua; Zhang, Jiong; Song, Shiping; Fan, Chunhai

    2007-01-01

    In this work, we reported a systematic investigation on the interactions between methylene blue (MB) and surface-confined DNA by using electrochemical methods. We demonstrated that the redox potential of MB and binding and dissociation kinetics of MB to DNA differed significantly for single-stranded DNA (ss-DNA) and double-stranded DNA (ds-DNA) immobilized on gold electrodes. This was possibly due to the different binding mechanism between MB and ss- or ds-DNA. This work might provide useful information for developing MB-based sequence-specific electrochemical DNA sensors.

  14. Spontaneous formation of an ordered structure during dip-coating of methylene blue on fused quartz

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hiroyuki; Takahashi, Mutsuko; Kotani, Masahiro

    2001-12-01

    Molecular orientation in thin films of methylene blue, prepared by dip-coating, has been studied by UV-visible absorption spectroscopy and X-ray diffraction. In multilayered films the molecules are essentially standing normal to the surface of a fused quartz substrate and form a layered structure with a periodicity that corresponds to the molecular length. Due to this arrangement the film is only faintly colored, since, with normal incidence, the electric field of the incident light is orthogonal to the transition moment of the molecules. This structure can be formed by self-organization in the course of drying, not by epitaxy.

  15. Methylene blue does not reverse existing neurofibrillary tangle pathology in the rTg4510 mouse model of tauopathy.

    PubMed

    Spires-Jones, Tara L; Friedman, Taylor; Pitstick, Rose; Polydoro, Manuela; Roe, Allyson; Carlson, George A; Hyman, Bradley T

    2014-03-06

    Alzheimer's disease is characterized pathologically by aggregation of amyloid beta into senile plaques and aggregation of pathologically modified tau into neurofibrillary tangles. While changes in amyloid processing are strongly implicated in disease initiation, the recent failure of amyloid-based therapies has highlighted the importance of tau as a therapeutic target. "Tangle busting" compounds including methylene blue and analogous molecules are currently being evaluated as therapeutics in Alzheimer's disease. Previous studies indicated that methylene blue can reverse tau aggregation in vitro after 10 min, and subsequent studies suggested that high levels of drug reduce tau protein levels (assessed biochemically) in vivo. Here, we tested whether methylene blue could remove established neurofibrillary tangles in the rTg4510 model of tauopathy, which develops robust tangle pathology. We find that 6 weeks of methylene blue dosing in the water from 16 months to 17.5 months of age decreases soluble tau but does not remove sarkosyl insoluble tau, or histologically defined PHF1 or Gallyas positive tangle pathology. These data indicate that methylene blue treatment will likely not rapidly reverse existing tangle pathology.

  16. Potential Biosorbent Derived from Calligonum polygonoides for Removal of Methylene Blue Dye from Aqueous Solution

    PubMed Central

    Nasrullah, Asma; Khan, Hizbullah; Khan, Amir Sada; Man, Zakaria; Muhammad, Nawshad; Khan, Muhammad Irfan; Abd El-Salam, Naser M.

    2015-01-01

    The ash of C. polygonoides (locally called balanza) was collected from Lakki Marwat, Khyber Pakhtunkhwa, Pakistan, and was utilized as biosorbent for methylene blue (MB) removal from aqueous solution. The ash was used as biosorbent without any physical or chemical treatment. The biosorbent was characterized by using various techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The particle size and surface area were measured using particle size analyzer and Brunauer-Emmett-Teller equation (BET), respectively. The SEM and BET results expressed that the adsorbent has porous nature. Effects of various conditions such as initial concentration of methylene blue (MB), initial pH, contact time, dosage of biosorbent, and stirring rate were also investigated for the adsorption process. The rate of the adsorption of MB on biomass sample was fast, and equilibrium has been achieved within 1 hour. The kinetics of MB adsorption on biosorbent was studied by pseudo-first- and pseudo-second-order kinetic models and the pseudo-second-order has better mathematical fit with correlation coefficient value (R2) of 0.999. The study revealed that C. polygonoides ash proved to be an effective, alternative, inexpensive, and environmentally benign biosorbent for MB removal from aqueous solution. PMID:25705714

  17. Modeling methylene blue aggregation in acidic solution to the limits of factor analysis.

    PubMed

    Golz, Emily K; Vander Griend, Douglas A

    2013-01-15

    Methylene blue (MB(+)), a common cationic thiazine dye, aggregates in acidic solutions. Absorbance data for equilibrated solutions of the chloride salt were analyzed over a concentration range of 1.0 × 10(-3) to 2.6 × 10(-5) M, in both 0.1 M HCl and 0.1 M HNO(3). Factor analyses of the raw absorbance data sets (categorically a better choice than effective absorbance) definitively show there are at least three distinct molecular absorbers regardless of acid type. A model with monomer, dimer, and trimer works well, but extensive testing has resulted in several other good models, some with higher order aggregates and some with chloride anions. Good models were frequently indistinguishable from each other by quality of fit or reasonability of molar absorptivity curves. The modeling of simulated data sets demonstrates the cases and degrees to which signal noise in the original data obscure the true model. In particular, the more mathematically similar (less orthogonal) the molar absorptivity curves of the chemical species in a model are, the less signal noise it takes to obscure the true model from other potentially good models. Unfortunately, the molar absorptivity curves in dye aggregation systems like that of methylene blue tend to be sufficiently similar so as to lead to the obscuration of models even at the noise levels (0.0001 ABS) of typical benchtop spectrophotometers.

  18. Supramolecular hybrids of polytungstates and their adsorption properties for methylene blue

    SciTech Connect

    Liu, Yunping; Zheng, Ran; Han, Zhangang Gong, Kaining; He, Xueli; Zhai, Xueliang

    2015-11-15

    Two supramolecular hybrids [Ni(mbpy){sub 3}]{sub 2}[V{sub 2}W{sub 4}O{sub 19}]·6H{sub 2}O (1) and [Ni(mbpy){sub 3}]{sub 2}[VW{sub 12}O{sub 40}] (2) (mbpy=4,4′-dimethyl-2,2′-bipyridyl) had been synthesized and characterized. Single crystal X-ray diffraction analyses revealed that the anionic moieties in two hybrids belong to typical Lindqvist and α-Keggin-type structures, respectively. The counter ion [Ni(mbpy){sub 3}]{sup 2+} units were anchored to the polyanions via non-covalent intermolecular interactions. These supramolecular hybrids exhibit reversible adsorption–desorption performance for organic dye methylene blue (MB). Hybrid 2 shows a fast adsorption behavior towards MB and a relatively high value can be reached within 5 min in dark. Both 1 and 2 are structurally stable and can be easily separated from the reaction system for reuse. - Graphical abstract: Supramolecular hybrids of polytungstates have been synthesized and characterized, which exhibit the reversible adsorption–desorption performance for organic dye methylene blue.

  19. [Adsorption of methylene blue from aqueous solution onto magnetic Fe3O4/ graphene oxide nanoparticles].

    PubMed

    Chang, Qing; Jiang, Guo-Dong; Hu, Meng-Xuan; Huang, Jia; Tang, He-Qing

    2014-05-01

    A simple ultrasound-assisted co-precipitation method was developed to prepare magnetic Fe3O4/graphene oxide (Fe3O4/ GO) nanoparticles. The characterization with transmission electron microscope (TEM) indicated that the products possessed small particle size. The hysteresis loop of the dried Fe3O4/GO nanoparticles demonstrated that the sample had typical features of superparamagnetic material. Batch adsorption studies were carried out to investigate the effects of the initial pH of the solution, the dosage of adsorbent, the contact time and temperature on the adsorption of methylene blue. The results indicated that the composites prepared could be used over a broad pH range (pH 6-9). The adsorption process was very fast within the first 25 min and the equilibrium was reached at 180 min. The adsorption equilibrium and kinetics data fitted well with the Langmuir isotherm model and the pseudo-second-order kinetic model. The adsorption process was a spontaneous and endothermic process in nature. The composite exhibited fairly high adsorption capacity (196.5 mg.g-1) of methylene blue at 313 K. In addition, the magnetic composite could be effectively and simply separated by using an external magnetic field, and then regenerated by hydrogen peroxide and recycled for further use. The results indicated that the adsorbent had a potential in the application of the dye wastewater treatment.

  20. Removal of methylene blue from aqueous solution by adsorption onto pineapple leaf powder.

    PubMed

    Weng, Chih-Huang; Lin, Yao-Tung; Tzeng, Tai-Wei

    2009-10-15

    The ability of an unconventional bio-adsorbent, pineapple leaf powder (PLP) for the adsorption of methylene blue (MB) from aqueous solution was studied. It was observed that intra-particle diffusion was involved in the adsorption process and that the kinetic data fitted well with a pseudo-second-order equation. Fitting parameters revealed that the rate of adsorption increased with decrease in dye concentration and decrease in ionic strength while the mixing speed did not have a significant effect on adsorption. The adsorption was favorable at higher pH and lower temperature, and the equilibrium data were well fitted by the Langmuir isotherm. The maximum adsorption capacity varied from 4.68 x 10(-4) to 9.28 x 10(-4)mol/g when pH increases from 3.5 to 9.5. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. The results revealed that this agricultural waste has potential to be used as an economical adsorbent for the removal of methylene blue from aqueous solution.

  1. Adsorptional removal of methylene blue by guar gum-cerium (IV) tungstate hybrid cationic exchanger.

    PubMed

    Gupta, V K; Pathania, Deepak; Singh, Pardeep; Kumar, Amit; Rathore, B S

    2014-01-30

    Guar gum-cerium (IV) tungstate nanocomposite (GG/CTNC) cationic exchanger was synthesized using simple sol gel method. The GG/CTNC was characterized using X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectrophotometer (EDX). The XRD studies confirmed amorphous and fibrous in nature of GG/CTNC. The high percentage of oxygen in the nanocomposite material confirmed the functionality tungstate (WO4(-)). The ion exchange capacity of GG/CTNC for Na(+) ion was observed to be 1.30 mequivg(-1). The hybrid exchanger was used as potential adsorbent for the removal of methylene blue (MB) from aqueous system. The correlation coefficients value indicated a good fit of monolayer Langmuir model to the adsorption of methylene blue onto GG/CTNC. The adsorption kinetic study revealed that the adsorption process followed the pseudo second order kinetic. The Gibbs free energy (ΔG) values confirmed the spontaneous nature of adsorption process.

  2. Hybrid multiwalled carbon nanotube--Laponite sorbent for removal of methylene blue from aqueous solutions.

    PubMed

    Loginov, Maksym; Lebovka, Nikolai; Vorobiev, Eugene

    2014-10-01

    The article discusses adsorption of methylene blue dye by novel hybrid sorbent consisting of Laponite and multiwalled carbon nanotubes. The sorbent was obtained by sonication of the aqueous suspensions of nanotubes at different concentrations of Laponite. The methods of the methylene blue adsorption, dead-end membrane filtration and environmental scanning electron microscopy were used for the sorbent characterization. It may be concluded from the results of filtration and adsorption experiments that sonication of mixed aqueous suspensions of Laponite and multiwalled carbon nanotubes leads to the formation of hybrid particles (ML-particles) with a core-shell structure. The size and the shape of hybrid particles were determined by nanotubes, while their adsorption properties were determined by Laponite particles attached to the surface of nanotubes. The Laponite content in hybrid particles was corresponding to the Laponite to nanotubes ratio in the initial suspension X(L)=0-1. Due to the presence of Laponite in the sorbent, its adsorbing capacity was much higher as compared to the adsorbing capacity of pure nanotubes, and it was directly proportional to the Laponite content. This sorbent may be used either as a purifying additive or as a filtering layer if it is deposited on the surface of a supporting membrane. Due to relatively large size of hybrid particles, they can be easily separated from the purified solution by filtration or centrifugation.

  3. Kinetics and thermodynamics of adsorption of methylene blue by a magnetic graphene-carbon nanotube composite

    NASA Astrophysics Data System (ADS)

    Wang, Peifang; Cao, Muhan; Wang, Chao; Ao, Yanhui; Hou, Jun; Qian, Jin

    2014-01-01

    A solvothermal method was employed to prepare a novel magnetic composite adsorbent composed of graphene, multi-walled carbon nanotubes (MWCNTs) and Fe3O4 nanoparticles. The prepared adsorbents were characterized by X-ray diffraction, scanning electron microscopy and X-ray fluorescence spectrometry and Fourier transform infrared spectroscopy. Fourier transform infrared spectroscopy and the particle size distribution of the samples before and after adsorption was also carried out. The performance of as-prepared composites was investigated by the adsorption of dye methylene blue. Results showed that the maximum adsorption capacity of the samples was up to 65.79 mg g-1, which was almost equal to the sum of magnetic graphene and magnetic MWCNTs. The effect of pH and temperature on the adsorption performance of methylene blue onto the magnetic adsorbents was investigated. The kinetic was well-described by pseudo-second-order and intraparticle diffusion model, while the isotherm obeyed the Langmuir isotherm. Furthermore, the as-prepared composites were found to be regenerative and reusable. The application in the treatment of an artificial dye wastewater and its cost estimation were also discussed. Therefore, the as-prepared magnetic composites can be severed as a potential adsorbent for removal of dye pollutant, owing to its high adsorption performance, magnetic separability and efficient recyclable property.

  4. Kinetic studies on the adsorption of methylene blue onto vegetal fiber activated carbons

    NASA Astrophysics Data System (ADS)

    Cherifi, Hakima; Fatiha, Bentahar; Salah, Hanini

    2013-10-01

    The vegetable sponge of cylindrical loofa (CL), a natural product which grows in the north of Algeria, was used to prepare activated carbons. Two activated carbons, AC1 and AC2, by two physiochemical activation methods to be used for methylene blue removal from wastewater. The surface structure of AC1, AC2 and CL were analyzed by scanning electron microscopy. Adsorption isotherm of methylene blue onto the prepared activated carbons was determined by batch tests. The effects of various parameters such as contact time, initial concentration, pH, temperature, adsorbent dose and granulometry were investigated, at agitation rate 150 rpm. The results showed that the equilibrium uptake increased with increasing initial MB concentration. The maximum % removal of MB obtained was 99% at 50 °C for AC1 and 82% at 30 °C for AC2. The increase in initial pH in the ranges of 2-10 increases the yields removal of MB on AC2. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data. The latter provided the best correlation of the experimental data compared to the pseudo-first-order model.

  5. Removal of methylene blue from aqueous solution using cotton stalk, cotton waste and cotton dust.

    PubMed

    Ertaş, Murat; Acemioğlu, Bilal; Alma, M Hakkı; Usta, Mustafa

    2010-11-15

    In this study, cotton stalk (CS), cotton waste (CW) and cotton dust (CD) was used as sorbents to remove methylene blue (MB) from aqueous solution by batch sorption technique. Effects of initial dye concentration, solution pH, solution temperature and sorbent dose on sorption were studied. It was seen that the removal of methylene blue increased with increasing initial dye concentration (from 25 to 100 mg/l), solution pH (from 5 to 10), solution temperature (from 20 to 50°C) and sorbent dose (from 0.25 to 1.50 g/50 ml). The maximum dye removal was reached at 90 min. Sorption isotherms were analyzed by Langmuir and Freundlich models at different temperatures of 20, 30, 40 and 50°C, and the results were discussed in detail. Moreover, the thermodynamics of sorption were also studied. It was found that the values of standard free energy (ΔG°) were positive for cotton stalk and negative for cotton waste and cotton dust. The values of standard enthalpy (ΔH°) and entropy (ΔS°) were found to be positive, and the obtained results were interpreted in detail. The results of this study showed that cotton stalk, cotton waste and cotton dust could be employed as effective and low-cost materials for the removal of dyes from aqueous solution.

  6. Potential biosorbent derived from Calligonum polygonoides for removal of methylene blue dye from aqueous solution.

    PubMed

    Nasrullah, Asma; Khan, Hizbullah; Khan, Amir Sada; Man, Zakaria; Muhammad, Nawshad; Khan, Muhammad Irfan; Abd El-Salam, Naser M

    2015-01-01

    The ash of C. polygonoides (locally called balanza) was collected from Lakki Marwat, Khyber Pakhtunkhwa, Pakistan, and was utilized as biosorbent for methylene blue (MB) removal from aqueous solution. The ash was used as biosorbent without any physical or chemical treatment. The biosorbent was characterized by using various techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The particle size and surface area were measured using particle size analyzer and Brunauer-Emmett-Teller equation (BET), respectively. The SEM and BET results expressed that the adsorbent has porous nature. Effects of various conditions such as initial concentration of methylene blue (MB), initial pH, contact time, dosage of biosorbent, and stirring rate were also investigated for the adsorption process. The rate of the adsorption of MB on biomass sample was fast, and equilibrium has been achieved within 1 hour. The kinetics of MB adsorption on biosorbent was studied by pseudo-first- and pseudo-second-order kinetic models and the pseudo-second-order has better mathematical fit with correlation coefficient value (R (2)) of 0.999. The study revealed that C. polygonoides ash proved to be an effective, alternative, inexpensive, and environmentally benign biosorbent for MB removal from aqueous solution.

  7. Methylene blue treatment delays progression of perfusion-diffusion mismatch to infarct in permanent ischemic stroke.

    PubMed

    Rodriguez, Pavel; Jiang, Zhao; Huang, Shiliang; Shen, Qiang; Duong, Timothy Q

    2014-11-07

    Stroke is a leading cause of morbidity and mortality in the world. Low-dose methylene blue (MB), which has been used safely to treat methemoglobinemia and cyanide poisoning in humans, has energy enhancing and antioxidant properties. We tested the hypothesis that methylene blue treatment delays progression of at-risk tissue (ca. perfusion-diffusion mismatch) to infarct in permanent middle cerebral artery occlusion in rats at two MB treatment doses. Serial MRI was used to evaluate MB treatment efficacy. The major findings were: (i) MB significantly prolonged the perfusion-diffusion mismatch, (ii) MB mildly increased the CBF in the hypoperfused tissue, (iii) MB did not change the final infarct volume in permanent ischemic stroke, and (iv) there were no dose-dependent effects on mismatch progression for the 1 and 3mg/kg doses studied. This neuroprotective effect is likely the result of sustained ATP production and increased CBF to tissue at risk. This work has the potential to readily lead to clinical stroke trials given MB's excellent safety profile.

  8. Synthesis and characterization of magnetic palygorskite nanoparticles and their application on methylene blue remotion from water

    NASA Astrophysics Data System (ADS)

    Middea, Antonieta; Spinelli, Luciana S.; Souza, Fernando G.; Neumann, Reiner; Gomes, Otavio da F. M.; Fernandes, Thais L. A. P.; de Lima, Luiz C.; Barthem, Vitoria M. T. S.; de Carvalho, Fernanda V.

    2015-08-01

    Recently there has been considerable interest in magnetic sorbents materials, which is added excellent capabilities such as sorption and magnetic response to an applied field. Accordingly, palygorskite nanoparticles were covered by magnetite using a co-precipitation technique and characterized by: X-ray fluorescence (XRF), X-ray diffraction (XRD), surface analysing and scanning electron microscopy (SEM) with element analysis and mapping, particle size, pore surface area (BET), density, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and zeta potential. Additionally, magnetic properties were studied by SQUID magnetometer, magnetic force microscopy (MFM) and also using a simple experimental setup. Magnetic nanoparticles produced had average diameters in a nanometric range. The amount of iron present in the nanoparticles increased by six times after the magnetization and a superparamagnetic behavior was exhibited with high saturation magnetization, from 4.0 × 10-4 Am2/kg to about 20 Am2/kg. A weight loss was also observed around 277 °C-339 °C by TGA, indicating a structural change from magnetite to maghemite, which confirms the magnetization of palygorskite. Batch adsorption experiments were carried out for the removal of methylene blue cationic dye from aqueous solution using pure and covered by magnetite palygorskite nanoparticles as adsorbents. Furthermore, about 90% of methylene blue was removed within 3 min using magnetized palygorskite.

  9. Performance evaluation of phase holograms recorded in methylene-blue-sensitized dichromated gelatin

    NASA Astrophysics Data System (ADS)

    Pappu, Sastry V.; Changkakoti, Rupak

    1990-04-01

    Systematic studies have been carried out on the performance evaluation of volume phase holograms recorded in methylene blue sensitized dichromated gelatin (MBDCG) to identify the conditions to be fulfilled to realize optimum difraction efficiency in such holograms.A noteworthy feature of the studies is that inexpensive nonstandard gelatin has been used. The studies have revealed that optimum diffraction efficiency can be achieved when, (a) the pH of the first development bath is kept around 65; (b) the concentration of axnmonium dichromate as prehardner is maintained around 0.5 '1. by weight of gelatin; (c) the concentration of ammonium dichromate and methylene blue photo.sensitizers is fixed around 30 gm/litre and 0.3 gm/litre respectively;and (d) no external electron donor is added.Further,it is found that the decrease in diffraction efficiency consequent upon the storage of holograms can be restored almost perfectly to the original level by reprocessing the holograms.Based on our studies, it is proposed that DCG can be used fruitfully as a model information recording medium to investigate such aspects as senility,information loss and restoration,in the context of the development of optical memories.

  10. Modified use of methylene blue in the tissue compression technique to detect sarcocysts in meat-producing animals.

    PubMed

    Ng, Yit Han; Subramaniam, Vellayan; Lau, Yee Ling

    2015-11-30

    Sarcocystosis in meat-producing animals is a major cause of reduced productivity in many countries, especially those that rely on agriculture. Although several diagnostic methods are available to detect sarcocystosis, many are too time-consuming for routine use in abattoirs and meat inspection centers, where large numbers of samples need to be tested. This study aimed to compare the sensitivity of the methylene blue tissue preparation, unstained tissue preparation and nested PCR in the detection of sarcocysts in tissue samples. Approximately three-fold more sarcocysts were detected in methylene blue-stained tissue compared to unstained controls (McNemar's test: P<0.01). Test sensitivity was comparable to that of the gold standard for sarcocyst detection, nested polymerase chain reaction. These results suggest that methylene blue can be used in tissue compression as a rapid, safe, and inexpensive technique for the detection of ruminant sarcocystosis in abattoirs.

  11. Catalytic reduction of methylene blue by sulfide ions in the presence of nanoAlMCM-41 material

    NASA Astrophysics Data System (ADS)

    Sohrabnezhad, Sh.; Pourahmad, A.; Rakhshaee, R.; Radaee, A.; Heidarian, S.

    2010-03-01

    This article reports the reduction of methylene blue (MB) by sulfide ions (S 2-) in aqueous solution by a nanoAlMCM-41 catalyst. The results obtained showed that, under acidic conditions (pH=2) MB was reduced to the Leuco methylene blue (LMB) form by sulfide ions and by changing the pH between 2.0 and 7.0 a reduction of the MB dye to the MBH 2+ form was observed. In alkaline media (pH=8), a reduction of methylene blue by sulfide ions to the MBH 2+ form and demethylation of the dye was observed simultaneously. The demethylation of MB leads to a thionine dye product. Using nanoAlMCM-41 but with encapsulated CoS nanoparticles only causes demethylation of MB in aqueous solution.

  12. Methylene blue microbubbles as a model dual-modality contrast agent for ultrasound and activatable photoacoustic imaging.

    PubMed

    Jeon, Mansik; Song, Wentao; Huynh, Elizabeth; Kim, Jungho; Kim, Jeesu; Helfield, Brandon L; Leung, Ben Y C; Goertz, David E; Zheng, Gang; Oh, Jungtaek; Lovell, Jonathan F; Kim, Chulhong

    2014-01-01

    Ultrasound and photoacoustic imaging are highly complementary modalities since both use ultrasonic detection for operation. Increasingly, photoacoustic and ultrasound have been integrated in terms of hardware instrumentation. To generate a broadly accessible dual-modality contrast agent, we generated microbubbles (a standard ultrasound contrast agent) in a solution of methylene blue (a standard photoacoustic dye). This MB2 solution was formed effectively and was optimized as a dual-modality contrast solution. As microbubble concentration increased (with methylene blue concentration constant), photoacoustic signal was attenuated in the MB2 solution. When methylene blue concentration increased (with microbubble concentration held constant), no ultrasonic interference was observed. Using an MB2 solution that strongly attenuated all photoacoustic signal, high powered ultrasound could be used to burst the microbubbles and dramatically enhance photoacoustic contrast (>800-fold increase), providing a new method for spatiotemporal control of photoacoustic signal generation.

  13. Methylene blue microbubbles as a model dual-modality contrast agent for ultrasound and activatable photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Jeon, Mansik; Song, Wentao; Huynh, Elizabeth; Kim, Jungho; Kim, Jeesu; Helfield, Brandon L.; Leung, Ben Y. C.; Goertz, David E.; Zheng, Gang; Oh, Jungtaek; Lovell, Jonathan F.; Kim, Chulhong

    2014-01-01

    Ultrasound and photoacoustic imaging are highly complementary modalities since both use ultrasonic detection for operation. Increasingly, photoacoustic and ultrasound have been integrated in terms of hardware instrumentation. To generate a broadly accessible dual-modality contrast agent, we generated microbubbles (a standard ultrasound contrast agent) in a solution of methylene blue (a standard photoacoustic dye). This MB2 solution was formed effectively and was optimized as a dual-modality contrast solution. As microbubble concentration increased (with methylene blue concentration constant), photoacoustic signal was attenuated in the MB2 solution. When methylene blue concentration increased (with microbubble concentration held constant), no ultrasonic interference was observed. Using an MB2 solution that strongly attenuated all photoacoustic signal, high powered ultrasound could be used to burst the microbubbles and dramatically enhance photoacoustic contrast (>800-fold increase), providing a new method for spatiotemporal control of photoacoustic signal generation.

  14. Evaluation of papaya seeds as a novel non-conventional low-cost adsorbent for removal of methylene blue.

    PubMed

    Hameed, B H

    2009-03-15

    The feasibility of using papaya seeds (PS), abundantly available waste in Malaysia, for the cationic dye (methylene blue) adsorption has been investigated. Batch adsorption studies were conducted to study the effects of contact time, initial concentration (50-360 mg/L), pH (3-10) and adsorbent dose (0.05-1.00 g) on the removal of methylene blue (MB) at temperature of 30 degrees C. The equilibrium data were analyzed by the Langmuir, the Freundlich and the Temkin isotherms. The data fitted well with the Langmuir model with a maximum adsorption capacity of 555.557 mg/g. The pseudo-second-order kinetics was the best for the adsorption of MB by PS with good correlation. The results demonstrated that the PS is very effective to remove methylene blue from aqueous solutions.

  15. Facile decolorization of methylene blue by morphology-dependence δ-MnO2 nanosheets -modified diatomite

    NASA Astrophysics Data System (ADS)

    Yu, Ting Ting; Li, Kai Lin; Guo, Xiao Long; Li, Fei; Huang, Jia Mu; Zhang, Yu Xin

    2015-12-01

    In this work, coscinodiscus-diatomite and melosira-diatomite have been decorated by ultrathin birnessite MnO2 (δ-MnO2) nanosheets through a one-pot hydrothermal method without using any surfactants. The δ-MnO2 nanosheets are observed to grow vertically on the purified melosira-diatomite as well as coscinodiscus-diatomite. Moreover, the two composites exhibit high efficiency for decomposing methylene blue (MB) in the presence of H2O2. The coscinodiscus-diatmite@MnO2 achieves a removal rate of 81.8% (2 h), and yet melosira-diatomite@MnO2 reaches a higher degradation rate of 91.3% in 2 h. Additionally, the effects of catalyst amount, catalysis reaction temperature, preparing time have also been investigated. In principle, the diverse diatomite@MnO2 nanostructures not only present an environmentally friendly and low cost with a good cycling stability, but also offer a simple way for the catalytic degradation of dye waste water in practical applications.

  16. Methylene blue not ferrocene: Optimal reporters for electrochemical detection of protease activity.

    PubMed

    González-Fernández, Eva; Avlonitis, Nicolaos; Murray, Alan F; Mount, Andrew R; Bradley, Mark

    2016-10-15

    Electrochemical peptide-based biosensors are attracting significant attention for the detection and analysis of proteins. Here we report the optimisation and evaluation of an electrochemical biosensor for the detection of protease activity using self-assembled monolayers (SAMs) on gold surfaces, using trypsin as a model protease. The principle of detection was the specific proteolytic cleavage of redox-tagged peptides by trypsin, which causes the release of the redox reporter, resulting in a decrease of the peak current as measured by square wave voltammetry. A systematic enhancement of detection was achieved through optimisation of the properties of the redox-tagged peptide; this included for the first time a side-by-side study of the applicability of two of the most commonly applied redox reporters used for developing electrochemical biosensors, ferrocene and methylene blue, along with the effect of changing both the nature of the spacer and the composition of the SAM. Methylene blue-tagged peptides combined with a polyethylene-glycol (PEG) based spacer were shown to be the best platform for trypsin detection, leading to the highest fidelity signals (characterised by the highest sensitivity (signal gain) and a much more stable background than that registered when using ferrocene as a reporter). A ternary SAM (T-SAM) configuration, which included a PEG-based dithiol, minimised the non-specific adsorption of other proteins and was sensitive towards trypsin in the clinically relevant range, with a Limit of Detection (LoD) of 250pM. Kinetic analysis of the electrochemical response with time showed a good fit to a Michaelis-Menten surface cleavage model, enabling the extraction of values for kcat and KM. Fitting to this model enabled quantitative determination of the solution concentration of trypsin across the entire measurement range. Studies using an enzyme inhibitor and a range of real world possible interferents demonstrated a selective response to trypsin

  17. Use of TOF-SIMS to study adsorption and loading behavior of methylene blue and papain in a nano-porous silicon layer.

    PubMed

    Kempson, Ivan M; Barnes, Timothy J; Prestidge, Clive A

    2010-02-01

    TOF-SIMS was applied to study the cross-sectional distribution of methylene blue and papain in porous silicon layers. Elemental and molecular information were used to study their distributions in the porous region and the chemistry of their adsorption. Methylene blue (MW = 284 Da) penetrated to the base to the pores. Positive ions (SiCH(3)(+)) suggest methylene blue binds to the substrate via its methyl groups. Negative fragments (SiOSH(3)(-) and SiO(2)SCH(-)) also suggested chemisorption via O bridging of the substrate Si and methylene blue S. The larger Papain molecule (23,406 Da) distributed itself in a similar manner to methylene blue demonstrating larger molecules can be effectively incorporated into such pore structures.

  18. Extractive spectrophotometric determination of some nonsteroidal anti-inflammatory drugs using methylene blue.

    PubMed

    El-Kommos, Michael E; Mohamed, Niveen A; Hakiem, Ahmed F Abdel

    2013-01-01

    A simple, rapid, sensitive, and accurate extractive spectrophotometric method has been developed for the determination of seven nonsteroidal anti-inflammatory drugs (NSAIDs)--namely diclofenac sodium, ibuprofen, indomethacin, ketoprofen, ketorolac tromethamine, mefenamic acid, and naproxen-in pure forms as well as their pharmaceutical dosage forms (tablets, capsules, effervescent granules, syrups, oral drops, ampules, eye drops, gels, and suppositories). The method depends on the formation of an intensely colored ion-pair complex between the acidic drug and methylene blue in alkaline medium. The complex is stable and extractable into methylene chloride. All parameters were optimized. Beer-Lambert's law was obeyed in concentrations ranging from 0.04 to 9 microg/mL. Statistical analysis of the calibration data was carried out, and correlation coefficients were in the range from 0.9996 to 0.9998. The developed method was fully validated according to International Conference on Harmonization guidelines, and complied with U.S. Pharmacopeia guidelines. The proposed method was applied to the analysis of the investigated drugs in their pharmaceutical formulations, and good recoveries were obtained. The results obtained were compared with those of reported and official methods, and no significant differences were found with t- and F-tests. Interference effects of some compounds usually present in combination with NSAIDs were studied, and the tolerance limits of these compounds were determined.

  19. Methylene blue removal from contaminated waters using O3, natural zeolite, and O3/zeolite.

    PubMed

    Valdés, H; Tardón, R F; Zaror, C A

    2009-01-01

    This paper compares experimental results on methylene blue (MB) removal systems based on ozone oxidation, zeolite adsorption, and simultaneous adsorption-oxidation using ozone in the presence of natural zeolite. The effect of pH (2-8), and the presence of radical scavengers (sodium acetate) on process rates and removal efficiencies are assessed at laboratory scale. The experimental system consisted of a 1 L differential circular flow reactor and an ozone generator rated at 5 g O3/h. Results show that ozone oxidation combined with zeolite adsorption increases the overall MB oxidation rate with respect to ozonation process and zeolite adsorption. In presence of free radical scavenger, only a 25% of reduction on MB removal rate are observed in the simultaneous treatment, as compared with 70% when ozonation treatment is used, suggesting that MB oxidation reactions take mainly place on the zeolite surface.

  20. Ultrasound-guided percutaneous injection of methylene blue to identify nerve pathology and guide surgery.

    PubMed

    Osorio, Joseph A; Breshears, Jonathan D; Arnaout, Omar; Simon, Neil G; Hastings-Robinson, Ashley M; Aleshi, Pedram; Kliot, Michel

    2015-09-01

    OBJECT The objective of this study was to provide a technique that could be used in the preoperative period to facilitate the surgical exploration of peripheral nerve pathology. METHODS The authors describe a technique in which 1) ultrasonography is used in the immediate preoperative period to identify target peripheral nerves, 2) an ultrasound-guided needle electrode is used to stimulate peripheral nerves to confirm their position, and then 3) a methylene blue (MB) injection is performed to mark the peripheral nerve pathology to facilitate surgical exploration. RESULTS A cohort of 13 patients with varying indications for peripheral nerve surgery is presented in which ultrasound guidance, stimulation, and MB were used to localize and create a road map for surgeries. CONCLUSIONS Preoperative ultrasound-guided MB administration is a promising technique that peripheral nerve surgeons could use to plan and execute surgery.

  1. Methylene blue adsorption from aqueous solution by activated carbon: effect of acidic and alkaline solution treatments.

    PubMed

    Ijagbemi, Christianah O; Chun, Ji I; Han, Da H; Cho, Hye Y; O, Se J; Kim, Dong S

    2010-01-01

    The removal of Methylene Blue (MB) from aqueous solution using activated carbon (AC) has been investigated. Adsorption experiments were conducted and the maximum adsorption capacity was determined. The effect of experimental parameters such as pH, dye concentration and temperature were studied on the adsorption process. Equilibrium data were mathematically modeled using the Langmuir and Freundlich adsorption models to describe the equilibrium isotherms at different dye concentrations and temperature. Parameters of best-fit model were calculated and discussed. To understand the mechanism of adsorption, kinetic models were employed to follow the adsorption processes; the pseudo-first-order best described the adsorption of MB onto AC. It was found that pH plays a major role in the adsorption process; adsorption capacity was influenced by the physical and surface chemical properties of carbon and the pH of the solution. 99.0% MB removal was achieved at equilibrium.

  2. Supramolecular hybrids of polytungstates and their adsorption properties for methylene blue

    NASA Astrophysics Data System (ADS)

    Liu, Yunping; Zheng, Ran; Han, Zhangang; Gong, Kaining; He, Xueli; Zhai, Xueliang

    2015-11-01

    Two supramolecular hybrids [Ni(mbpy)3]2[V2W4O19]·6H2O (1) and [Ni(mbpy)3]2[VW12O40] (2) (mbpy=4,4ʹ-dimethyl-2,2ʹ-bipyridyl) had been synthesized and characterized. Single crystal X-ray diffraction analyses revealed that the anionic moieties in two hybrids belong to typical Lindqvist and α-Keggin-type structures, respectively. The counter ion [Ni(mbpy)3]2+ units were anchored to the polyanions via non-covalent intermolecular interactions. These supramolecular hybrids exhibit reversible adsorption-desorption performance for organic dye methylene blue (MB). Hybrid 2 shows a fast adsorption behavior towards MB and a relatively high value can be reached within 5 min in dark. Both 1 and 2 are structurally stable and can be easily separated from the reaction system for reuse.

  3. Effect of a magnetic field on the adsorptive removal of methylene blue onto wheat straw biochar.

    PubMed

    Li, Guoting; Zhu, Weiyong; Zhang, Chunyu; Zhang, Shen; Liu, Lili; Zhu, Lingfeng; Zhao, Weigao

    2016-04-01

    Biochar pyrolyzed from wheat straw was innovatively used for the adsorptive removal of cationic dye methylene blue through exposure to a magnetic field. The adsorption capability of the biochar pyrolyzed at 200 °C exceeded that of samples pyrolyzed at higher temperatures. The surface acidic functional groups of wheat straw biochar were deduced to be more sensitive to the effects of the external magnetic field. The enhancement of the magnetic field achieved by increases in the initial dye concentration, and a decrease in the biochar dosage and solution pH, were more significant compared with those caused by other conditions. Kinetic experiments indicated that chemisorption occurred during adsorption. The qmax values for dye adsorption without, and with, an external magnetic field were found to be 46.6 and 62.5mg/g, respectively. These demonstrated that wheat straw biochar could be used for the efficient adsorption of pollutants when assisted by an external magnetic field.

  4. Adsorption characteristics of methylene blue onto agricultural wastes lotus leaf in bath and column modes.

    PubMed

    Han, Xiuli; Wang, Wei; Ma, Xiaojian

    2011-01-01

    The adsorption potential of lotus leaf to remove methylene blue (MB) from aqueous solution was investigated in batch and fixed-bed column experiments. Langmuir, Freundlich, Temkin and Koble-Corrigan isotherm models were employed to discuss the adsorption behavior. The results of analysis indicated that the equilibrium data were perfectly represented by Temkin isotherm and the Langmuir saturation adsorption capacity of lotus leaf was found to be 239.6 mg g(-1) at 303 K. In fixed-bed column experiments, the effects of flow rate, influent concentration and bed height on the breakthrough characteristics of adsorption were discussed. The Thomas and the bed-depth/service time (BDST) models were applied to the column experimental data to determine the characteristic parameters of the column adsorption. The two models were found to be suitable to describe the dynamic behavior of MB adsorbed onto the lotus leaf powder column.

  5. Equilibrium models and kinetic for the adsorption of methylene blue on Co-hectorites.

    PubMed

    Ma, Jun; Jia, Yong-Zhong; Jing, Yan; Sun, Jin-He; Yao, Ying; Wang, Xiao-Hua

    2010-03-15

    The adsorption of methylene blue (MB) onto the surface of cobalt doping hectorite (Co-hectorite) was systematically studied. The physical properties of Co-hectorites were investigated, where characterizations were carried out by X-ray diffraction (XRD) and Electron Diffraction Spectrum (EDS) techniques, and morphology was examined by nitrogen adsorption. The sample with a Co content 5% (m/m) had a higher specific surface area than other Co-hectorites. The pore diameters were distributed between 2.5 and 5.0 nm. The adsorption results revealed that Co-hectorite surfaces possessed effective interactions with MB and bases, and greatest adsorption capacity achieved with Co content 5%, where the best-fit isotherm model was the Langmuir adsorption model. Kinetic studies were fitted to the pseudo-second-order kinetic model. The intraparticle diffusion was not the rate-limiting step for the whole reaction.

  6. Study on the methylene blue adsorption from wastewaters by pore-expanded calcium fluoride sludge adsorbent.

    PubMed

    Hong, Junming; Lin, Bing; Hong, Gui-Bing; Chang, Chang-Tang

    2014-04-01

    The adsorption of methylene blue (MB) onto pore-expanded calcium fluoride sludge (ECF) by the batch adsorption technique was investigated. The results showed that the adsorption capacity increased with increasing MB concentration but decreased as pH was increased. In order to investigate the adsorption mechanisms, three simplified isotherm models and kinetic models were used in this study. The best-fit adsorption isotherm was achieved with the Temkin model. Furthermore, the pseudo-second-order kinetic model agreed very well with the dynamical behavior for the adsorption of MB onto ECF. Thermodynamic studies revealed that the adsorption process of MB onto ECF was spontaneous and exothermic. The results indicated that ECF adsorbed MB efficiently and could be used as a waste adsorbent for the removal of cationic dyes in wastewater treatment.

  7. Adsorptive performance for methylene blue of magnetic Ni@activated carbon nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Panfeng; Xu, Jingcai; Zhang, Beibei; Li, Jing; Jin, Hongxiao; Jin, Dingfeng; Peng, Xiaoling; Hong, Bo; Gong, Jie; Ge, Hongliang; Wang, Xinqing

    2015-11-01

    Owing to the unique microporous structure and high specific surface area, activated carbon (AC) can act as a good candidate for functional materials. In this paper, Ni@AC magnetic nanocomposites with excellent magnetic response are synthesized by the hydrothermal method. All Ni@AC nanocomposites present ferromagnetism and Ni nanoparticles exist in the pores of AC. The saturation magnetization (Ms) increases with the increasing content of Ni, while the specific surface area and pore volume decrease. The S-50 sample possesses the parameters of the specific surface area of 1156.8 m2 ṡ g-1 and Ms of 3.5 emu/g. Furthermore, the methylene blue (MB) removal analysis indicates that 99% MB can be adsorbed in 50 min. The as-prepared Ni@AC nanocomposites present good adsorptive capacity of MB and can be separated easily from water by magnetic separation technique.

  8. A Silver Nanoparticle-Modified Evanescent Field Optical Fiber Sensor for Methylene Blue Detection

    PubMed Central

    Luo, Ji; Yao, Jun; Lu, Yonggang; Ma, Wenying; Zhuang, Xuye

    2013-01-01

    A silver nanoparticle-modified evanescent field optical fiber sensor based on a MEMS microchannel chip has been successfully fabricated. Experimental results show that the sensor response decreases linearly with increasing concentration of analyte. Over a range of methylene blue concentrations from 0 to 0.4 μmol/mL, the sensor response is linear (R = 0.9496). A concentration variation of 0.1 μmol/mL can cause an absorbance change of 0.402 dB. Moreover, the optical responses of the same sensing fiber without decoration and modified with silver nanoparticles have also been compared. It can be observed that the output intensity of the Ag nanoparticle-modified sensor is enhanced and the sensitivity is higher. Meanwhile, the absorbance spectra are found to be more sensitive to concentration changes compared to the spectra of the peak wavelength. PMID:23519353

  9. Electrochemical behavior of an anticancer drug 5-fluorouracil at methylene blue modified carbon paste electrode.

    PubMed

    Bukkitgar, Shikandar D; Shetti, Nagaraj P

    2016-08-01

    A novel sensor for the determination of 5-fluorouracil was constructed by electrochemical deposition of methylene blue on surface of carbon paste electrode. The electrode surface morphology was studied using Atomic force microscopy and XRD. The electrochemical activity of modified electrode was characterized using cyclic voltammetry and differential pulse method. The developed sensor shows impressive enlargement in sensitivity of 5-fluorouracil determination. The peak currents obtained from differential pulse voltammetry was linear with concentration of 5-fluorouracil in the range 4×10(-5)-1×10(-7)M and detection limit and quantification limit were calculated to be 2.04nM and 6.18nM respectively. Further, the sensor was successfully applied in pharmaceutical and biological fluid sample analysis.

  10. Comparison effects and dielectric properties of different dose methylene-blue-doped hydrogels.

    PubMed

    Yalçın, O; Coşkun, R; Okutan, M; Öztürk, M

    2013-08-01

    The dielectric properties of methylene blue (MB)-doped hydrogels were investigated by impedance spectroscopy. The real part (ε') and the imaginary part (ε") of the complex dielectric constant and the energy loss tangent/dissipation factor (tan δ) were measured in the frequency range of 10 Hz to 100 MHz at room temperature for pH 5.5 value. Frequency variations of the resistance, the reactance, and the impedance of the samples have also been investigated. The dielectric permittivity of the MB-doped hydrogels is sensitive to ionic conduction and electrode polarization in low frequency. Furthermore, the dielectric behavior in high-frequency parts was attributed to the Brownian motion of the hydrogen bonds. The ionic conduction for MB-doped samples was prevented for Cole-Cole plots, while the Cole-Cole plots for pure sample show equivalent electrical circuit. The alternative current (ac) conductivity increases with the increasing MB concentration and the frequency.

  11. Electrochemical DNA sensor based on methylene blue functionalized polythiophene as a hybridization indicator.

    PubMed

    Liu, Mengqin; Luo, Chunhua; Peng, Hui

    2012-01-15

    A polythiophene functionalized with methylene blue (PMT-MB) was synthesized and used as an indicator for electrochemical oligonucleotides (ODNs) hybridization detection. After hybridization with complementary ODNs, the current signal of PMT-MB increased, which illustrated that PMT-MB can effectively recognize complementary ODN targets as an indicator. Compared to MB, PMT-MB showed much better resistance to the concentration change of buffer solution. In all buffer solutions tested, the hybridization always resulted in the increased current signal of PMT-MB due to the electrostatic interaction. While, when MB was used as an indicator, the inconsistent current response was obtained after the hybridization. When high concentration of buffer solution was used for accumulation, the hybridization resulted in the decreased current signal, while at the low concentrations, the current signal increased. The interaction between PMT-MB and dsODNs was also studied by UV-vis spectroscopy.

  12. Methylene blue protects astrocytes against glucose oxygen deprivation by improving cellular respiration.

    PubMed

    Roy Choudhury, Gourav; Winters, Ali; Rich, Ryan M; Ryou, Myoung-Gwi; Gryczynski, Zygmunt; Yuan, Fang; Yang, Shao-Hua; Liu, Ran

    2015-01-01

    Astrocytes outnumber neurons and serve many metabolic and trophic functions in the mammalian brain. Preserving astrocytes is critical for normal brain function as well as for protecting the brain against various insults. Our previous studies have indicated that methylene blue (MB) functions as an alternative electron carrier and enhances brain metabolism. In addition, MB has been shown to be protective against neurodegeneration and brain injury. In the current study, we investigated the protective role of MB in astrocytes. Cell viability assays showed that MB treatment significantly protected primary astrocytes from oxygen-glucose deprivation (OGD) & reoxygenation induced cell death. We also studied the effect of MB on cellular oxygen and glucose metabolism in primary astrocytes following OGD-reoxygenation injury. MB treatment significantly increased cellular oxygen consumption, glucose uptake and ATP production in primary astrocytes. In conclusion our study demonstrated that MB protects astrocytes against OGD-reoxygenation injury by improving astrocyte cellular respiration.

  13. Adsorption of methylene blue onto jute fiber carbon: kinetics and equilibrium studies.

    PubMed

    Senthilkumaar, S; Varadarajan, P R; Porkodi, K; Subbhuraam, C V

    2005-04-01

    Jute fiber obtained from the stem of a plant was used to prepare activated carbon using phosphoric acid. Feasibility of employing this jute fiber activated carbon (JFC) for the removal of Methylene blue (MB) from aqueous solution was investigated. The adsorption of MB on JFC has found to dependent on contact time, MB concentration and pH. Experimental result follows Langmuir isotherm model and the capacity was found to be 225.64 mg/g. The optimum pH for the MB removal was found to be 5-10. The kinetic data obtained at different concentrations have been analyzed using a pseudo-first-order, pseudo-second-order equation, intraparticle diffusion and Elovich equation. Among the kinetic models studied, the intraparticle diffusion was the best applicable model to describe the adsorption of MB onto JFC.

  14. LED-activated methylene blue-loaded Pluronic-nanogold hybrids for in vitro photodynamic therapy.

    PubMed

    Simon, Timea; Boca-Farcau, Sanda; Gabudean, Ana-Maria; Baldeck, Patrice; Astilean, Simion

    2013-12-01

    In this work we introduce a new class of multifunctional photodynamic agents based on the coupling of photosensitizer molecules with noble metal nanoparticles, which can be efficiently activated under low light intensity. The favourable modification of the photophysical properties of methylene blue (MB) in MB-loaded Pluronic-nanogold hybrids (Au-PF127-MB) increases the probability of singlet oxygen generation, which in turn allows the use of a light emitting diode (LED) irradiation source instead of commonly used, more invasive lasers. In this regard, Au-PF127-MB treated human lung carcinoma cells (HTB 177) were irradiated at different light doses, using a 660 nm LED source, the results indicating a dose dependent therapeutic effect, decreasing the cell viability down to 13%. Owing to their effectiveness, biocompatibility and integrated imaging and therapeutic functionalities, Au-PF127-MB could represent an important development in the field of biophotonic applications.

  15. Report: Simultaneous determination of naphazoline hydrochloride, chlorpheniramine maleate and methylene blue in their ternary mixture.

    PubMed

    Ali, Nouruddin Wageih; Hegazy, Maha Ahmad; Abdelkawy, Mohamad; Abdelfatah, Rehab Magdy

    2013-05-01

    Validated spectrophotometric and chemometric methods were developed for determination of Naphazoline Hydrochloride (NAP), Chlorpheniramine maleate (CLO) and Methylene blue (MB) in their ternary mixture. Method A was a spectrophotometric method, where NAP and MB were determined using second derivative (D²) spectrophoto metric method using the peak amplitudes at 299 nm and 337 nm for NAP and MB respectively , while CLO was determined using second derivative ratio (DD²) spectrophotometric method using the peak amplitude at 276.6 nm. Method B used the chemometric techniques; principal component regression (PCR) and partial least squares (PLS) for determination of NAP, CLO and MB using the information contained in the absorption spectra of their ternary mixture solutions. The proposed methods have been successfully applied for the analysis of NAP, CLO and MB in their pharmaceutical formulation and the obtained results were statistically compared with the reported methods.

  16. Fluorescence tissue distribution of methylene blue used for photodynamic therapy of Helicobacter Pylori

    NASA Astrophysics Data System (ADS)

    Millson, Charles E.; Buonaccorsi, Giovanni A.; MacRobert, Alexander J.; Mlkvy, Peter; Bown, Stephen G.

    1995-03-01

    Helicobacter pylori is associated with a wide range of pathologies in the upper gastrointestinal tract. Current treatments employing antibiotics are disappointing, and an endoscopic PDT might offer a better alternative. Methylene blue is a widely known histological dye and has been in use for photodynamic therapy experimentally for some years. A prospective application of MB is photosensitization of Helicobacter pylori, but little is known about its effect with light on normal mucosa of the stomach. We studied the fluorescence microscopy of the stomachs of 3 ferrets which had been sensitized by oral route with three different concentrations of MB 1 hour prior to sacrifice. MB at all doses was seen to concentrate on the surface of the mucosa and shows little deeper penetration. As Helicobacter lie on the superficial mucosa, this study suggests that oral dosing with MB should sensitize these bacteria. These findings are an important preliminary to an in vivo trial of PDT for the treatment of H pylori.

  17. Adsorptive removal of methylene blue by agar: effects of NaCl and ethanol

    PubMed Central

    2012-01-01

    Adsorption of methylene blue (MB) on agar was investigated as a function of temperature (308-328 K), different concentrations of NaCl and HCl and various weight percentages of binary mixtures of ethanol with water. It was observed that the maximum experimental adsorption capacity, qm, exp, in water is up to 50 mg g-1 and decreases with increase in weight percentage of ethanol and NaCl and HCl concentration compared to that of water. Analysis of data using ARIAN model showed that MB adsorbs as monomer and dimer on the surface of agar. Binding constants of MB to agar were calculated using the Temkin isotherm. The process is exothermic in water and other solutions. The mean adsorption energy (E) value indicated binding of MB to agar is chemical adsorption. Kinetics of this interaction obeys from the pseudo-second-order model and diffusion of the MB molecules into the agar is the main rate-controlling step. PMID:22339759

  18. Birnessite nanorod-mediated decomposition of methylene blue with common oxidants

    NASA Astrophysics Data System (ADS)

    Kannan, R.; Govindan, K.; Selvaraj, S.; Ravichandiran, P.; Vasanthkumar, S.

    2013-03-01

    In this paper, the birnessite nanorods (BN) were synthesized by microwave-assisted hydrothermal method and was characterized by powder X-ray diffraction measurements (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), and surface area (BET) analyzer. These results confirm the formation of birnessite nanorods. The catalytic decomposition profile of methylene blue by birnessite nanorods was tested. The effect of oxidants peroxomonosulfate (PMS) and peroxodisulfate (PDS) was compared with hydrogen peroxide (H2O2). Among these oxidants, PDS exhibits a high degree of decomposition of more than 80 % mineralization, achieved in 4 h when compared to PMS and H2O2. The decomposition was examined using varying amount of catalyst, which showed the dye decomposition activity to be proportional to the amount of the catalyst. The powder XRD studies showed no changes in the structure of birnessite nanorods, implying that these reactions are surface controlled.

  19. Wet chemical method for synthesizing 3D graphene/gold nanocomposite: catalytic reduction of methylene blue

    NASA Astrophysics Data System (ADS)

    Xie, Jiliang; Yang, Xujie; Xu, Xingyou

    2017-04-01

    In this paper, a simple and environmentally-friendly approach was reported to synthesize a novel 3D composite of graphene/gold nanoparticles (3DG/Au NPs) in one step. A 3D interlaced framework of graphene, which exhibited hierarchically porous structures, generated directly through the distinct driving force during the hydrothermal growth. Meanwhile, Au NPs with high dispersity, which displayed tunable morphologies, were immobilized on the framework, where the as-prepared graphene was employed as the endogenous reducing agent. Compared with AuNPs, the obtained 3DG/Au NPs exhibited remarkably convenient recyclability and high activity for the reduction of methylene blue which is a kind of organic dye.

  20. Removal of Methylene Blue and Orange-G from Waste Water Using Magnetic Biochar

    NASA Astrophysics Data System (ADS)

    Mubarak, N. M.; Fo, Y. T.; Al-Salim, Hikmat Said; Sahu, J. N.; Abdullah, E. C.; Nizamuddin, S.; Jayakumar, N. S.; Ganesan, P.

    2015-04-01

    The study on the removal of methylene blue (MB) and orange-G dyes using magnetic biochar derived from the empty fruit bunch (EFB) was carried out. Process parameters such as pH, adsorbent dosage, agitation speed and contact time were optimized using Design-Expert Software v.6.0.8. The statistical analysis reveals that the optimum conditions for the maximum adsorption of MB are at pH 2 and pH 10, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. While for orange-G, at pH 2, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. The maximum adsorption capacity of 31.25 mg/g and 32.36 mg/g for MB and orange-G respectively. The adsorption kinetic for both dyes obeyed pseudo-second order.

  1. Methylene-blue sensitized dichromated gelatin: wide-range colour adjustment of reflection hologram

    NASA Astrophysics Data System (ADS)

    Zhu, Jianhua; Dong, Guangxing; Guo, Xiaowei; Chen, Li; Li, Jianfeng

    2004-01-01

    In this paper a new technique is presented for adjusting the playback wavelength of reflection holograms recorded in methylene-blue sensitized dichromated gelatin (MBDCG). During the fabrication of the MBDCG medium, a water-soluble organic reagent is introduced homogeneously into the photosensitive layer as a preswelling reagent and wavelength adjuster. This method has a wide wavelength adjustment range (up to 200 nm, almost covering the entire visible spectral region), high diffraction efficiency and signal-to-noise ratio, and can be applied to quantitatively adjust the playback wavelength of reflection hologram by changing the concentration of the preswelling reagent. Its possible applications include colour image display, holographic optical elements, optical communication and optical anti-counterfeiting.

  2. Full-color holograms recorded in methylene blue sensitized dichromated gelatin

    NASA Astrophysics Data System (ADS)

    Kurokawa, Kazumasa; Koike, Satoshi; Namba, Shinji; Mizuno, Toru; Kubota, Toshihiro

    1995-07-01

    Methylene blue sensitized dichromated gelatin (MBDCG) is a suitable recording material for full color hologram in a single layer. Such a hologram has the possibility of being used as the advanced display devices and optical elements. However, the process of drying in an ammonia atmosphere is necessary for making the MBDCG. This process is troublesome and instable. A new method for preparing the MBDCG has been developed. The sensitized solution is composed of MB, ammonium dichromate, and gelatin in alkaline state. The MBDCG does not need to dry in an ammonia atmosphere when the concentration of MB and ammonium dichromate is properly controlled. The limits of the most suitable concentration of these agents are studied. Some experimental results of Lippmann color holograms using this MBDCG are presented.

  3. Catalytic ozone aqueous decomposition of methylene blue using composite metal oxides

    NASA Astrophysics Data System (ADS)

    Liu, Xuan; Hou, Yongjiang; Guo, Jie; Wang, Yaquan; Zuo, Qian; Wang, Chunyu

    2015-07-01

    By using the method of co-precipitation, Fe-Mn, Al-Mn, Al-Mg composite metal oxides were prepared. Using X-ray diffractometer(XRD), the phases of catalysts synthesized were observed to be Mn3O4 and Fe2O3. With the increase of the calcination temperature, Mn3O4 was gradually transformed into Mn2O3. The experimental results show that: the best catalyst is the Fe-Mn composite metal oxide with the calcination temperature of 650 °C. In this experimental condition, when the ozone amount was 1.92mg/min, and the dosage of catalyst was 0.5g, the removal rate of methylene blue (MB) was the best. The decolorization rate can reach to 100%. Compared with the effect of ozonation alone, the total organic carbon removal rate increased from 29.19% up to 65.78% after adding catalysts.

  4. Rapid and simple spectrophotometric determination of persulfate in water by microwave assisted decolorization of Methylene Blue.

    PubMed

    Zhao, Lajuan; Yang, Shiying; Wang, Leilei; Shi, Chao; Huo, Meiqing; Li, Yan

    2015-05-01

    A rapid and simple method for determination of persulfate in aqueous solution was developed. The method is based on the rapid reaction of persulfate with Methylene Blue (MB) via domestic microwave activation, which can promote the activation of persulfate and decolorize MB quickly. The depletion of MB at 644 nm (the maximum absorption wavelength of MB) is in proportion to the increasing concentration of persulfate in aqueous solution. Linear calibration curve was obtained in the range 0-1.5 mmol/L, with a limit of detection of 0.0028 mmol/L. The reaction time is rapid (within 60 sec), which is much shorter than that used for conventional methods. Compared with existing analytical methods, it need not any additives, especially colorful Fe2+, and need not any pretreatment for samples, such as pH adjustment.

  5. Successful Localization of Abnormal Parathyroid Gland Using Ultrasound-Guided Methylene Blue Dye Injection in the Reoperative Neck.

    PubMed

    Haciyanli, Mehmet; Koruyucu, Melike Bedel; Erdoğan, Nezahat Karaca; Dere, Ozcan; Sarı, Erdem; Kumkumoğlu, Yusuf; Tavusbay, Cengiz; Kamer, Erdinc

    2015-12-01

    Persistent or recurrent hyperparathyroidism is a challenging problem for endocrine surgeons. The aim of this study was to review our experience using ultrasound-guided (US-G) methylene blue dye injection for the localization and removal of abnormal parathyroid glands in patients having primary hyperparathyroidism and previous neck surgery. Between January 2012 and May 2013, six consecutive patients with primary hyperparathyroidism (PHPT) and previous neck surgery underwent focused parathyroidectomy with the use of US-G methylene blue dye injections to localize the presumed parathyroid adenoma were included in the study. We analyzed the data of six patients who underwent reoperative parathyroid surgery using US-G methylene blue dye injection retrospectively. The dye injection was performed just prior to surgery. All patients were successfully treated for their hyperparathyroidism which was confirmed by at least 50 % drop in intraoperative parathormone level 10 min after resection. There were no complications related with US-G dye injection or with surgery. US-G methylene blue dye injection is a cheap, safe, and effective method for localization of diseased parathyroid glands and guiding surgery in the reoperative neck.

  6. Desorption and photodegradation of methylene blue from modified sugarcane bagasse surface by acid TiO2 hydrosol

    NASA Astrophysics Data System (ADS)

    Yu, Jun-Xia; Chi, Ru-An; Guo, Jia; Zhang, Yue-Fei; Xu, Zhi-Gao; Xiao, Chun-Qiao

    2012-02-01

    Waste sugarcane bagasse (SCB) was modified by pyromellitic dianhydride to improve its adsorption capacity for cationic dyes. Results showed that the adsorption capacity of the modified SCB for methylene blue was 564 mg g-1, which was about 12 times than that obtained on the unmodified SCB. Methylene blue loaded modified SCB was regenerated by a self-clean eluent: TiO2 hydrosol with pH ranged from 1 to 4, and HNO3 solution with the same pH range was tested at the same time for comparison. Results showed that desorption kinetics of methylene blue in the hydrosol systems fit two-step kinetic model and controlled mainly by the slow step. As a self-clean eluent, acid hydrosol could firstly desorb and then photodegrade methylene blue under sunlight irradiation. After five desorption-photodegradation cycles, 78.3% of the absorbed dyes could be desorbed by using hydrosol (pH 2) as eluent. The hydrosol could be continuously used in desorption and photodegradation process, which would economize large volume of the eluent and moreover it would not bring secondary pollution.

  7. Photocatalytic decolorization of methylene blue in the presence of TiO2/ZnS nanocomposites.

    PubMed

    Franco, A; Neves, M C; Carrott, M M L Ribeiro; Mendonça, M H; Pereira, M I; Monteiro, O C

    2009-01-15

    The synthesis of distinct nanocrystalline TiO2 capped ZnS samples was carried out using a chemical deposition method. The materials characterization showed that the presence of ZnS onto TiO2 surface results in a red shift of the material band edge when compared with the initial semiconductor. The photocatalytic activity of the prepared nanocomposites was tested on the decolorization of methylene blue (MB) aqueous solutions. The dye photodecolorization process was studied considering the influence of experimental parameters such as catalyst concentration, TiO2/ZnS ratio, pH and methylene blue adsorption rate. The material with the best catalytic activity towards the methylene blue photodecolorization was the TiO2 doped with 0.2% of ZnS. The complete photodecolorization of a 20ppm methylene blue solution, at natural pH was achieved in less than 20min, nearly 70min faster than the TiO2 photoassisted process.

  8. Fixed-bed adsorption study of methylene blue onto pyrolytic tire char

    NASA Astrophysics Data System (ADS)

    Makrigianni, Vassiliki; Giannakas, Aris; Papadaki, Maria; Albanis, Triantafyllos; Konstantinou, Ioannis

    2016-04-01

    In this work, the adsorption efficiency of acid treated pyrolytic tire char to cationic methylene blue (MB) dye adsorption from aqueous solutions was investigated by fixed-bed adsorption column experiments. The effects of the initial dye concentration (10 - 40 mg L-1) and feed flow rate (50 - 150 mL min -1) with a fixed bed height (15 cm) were studied in order to determine the breakthrough characteristics of the adsorption system. The Adams-Bohart, Yoon-Nelson and Thomas model were applied to the adsorption of MB onto char at different operational conditions to predict the breakthrough curves and to determine the characteristic parameters of the column. The results showed that the maximum adsorbed quantities decreased with increasing flow rate and increased with increasing initial MB concentration. Breakthrough time and exhaustion time increased with decreasing inlet dye concentration and flow rate. In contrast with Adams-Bohart model, Yoon-Nelson model followed by Thomas model were found more suitable to describe the fixed-bed adsorption of methylene blue by char. The correlation coefficient values R2 for both models at different operating conditions are higher than 0.9 and the low average relative error values provided very good fittings of experimental data at different operating conditions. Higher adsorption capacity of 3.85 mg g -1 was obtained at 15 cm of adsorbent bed height, flow rate of 100 mL min -1and initial MB concentration of 40 mg L-1. Although that activated carbons exhibited higher adsorption capacities in the literature, acid-treated pyrolytic tire char was found to be considerably efficient adsorbent for the removal of MB dye column taking into account the advantages of the simpler production process compared to activated carbons, as well as, the availability of waste tire feedstock and concurrent waste tire management.

  9. Use of a methylene blue azide medium for isolation of enterococci.

    PubMed

    Smith, R F; Bodily, H L

    1967-09-01

    A methylene blue azide medium (MBA), developed by Schaedler, Dubos, and Costello to isolate enterococci from the gastrointestinal tract of animals, was evaluated. This was done by comparing the isolation of enterococci from feces and saliva on the medium. Fifty-two catalase-negative, gram-positive cocci from human feces isolated from MBA were classified as enterococci. All strains grew in S F, 6.5% NaCl, and streptomycin broths, and all fermented mannitol. The isolates were provisionally subdivided into Streptococcus faecalis and S. faecium groups. S. faecalis-like strains fermented glycerol and pyruvate aerobically and produced acid in Snyder's medium (initial pH, 4.8). The S. faecium group fermented raffinose. Among all strains, several tests were variable. These included growth at 45 C, in 0.1% tellurite and in methylene blue milk. Three methods were employed to isolate and identify enterococci from the oral cavity. Direct streaking of MBA with saliva failed to produce any growth on the medium. Two other methods, with the use of various selective broths to promote the recovery of oral enterococci, failed to produce any bacteria capable of growing on MBA. The MBA-isolated fecal strains and oral viridans streptococci were generally indistinguishable on Mitis-Salivarius and K F agars. In experiments with fecal material, no gram-negative bacilli were found among the isolates selected. The MBA medium was judged as a high selectivity-low yield medium, and may provide a means of separating fecal and nonfecal enterococci.

  10. Experimental and kinetic studies on methylene blue adsorption by coir pith carbon.

    PubMed

    Kavitha, D; Namasivayam, C

    2007-01-01

    Varying the parameters such as agitation time, dye concentration, adsorbent dose, pH and temperature carried out the potential feasibility of thermally activated coir pith carbon prepared from coconut husk for removal of methylene blue. Greater percentage of dye was removed with decrease in the initial concentration of dye and increase in amount of adsorbent used. Kinetic study showed that the adsorption of dye on coir pith carbon was a gradual process. Lagergren first-order, second-order, intra particle diffusion model and Bangham were used to fit the experimental data. Equilibrium isotherms were analysed by Langmuir, Freundlich, Dubnin-Radushkevich, and Tempkin isotherm. The adsorption capacity was found to be 5.87 mg/g by Langmuir isotherm for the particle size 250-500 microm. The equilibrium time was found to be 30 and 60 min for 10 and 20 mg/L and 100 min for 30, 40 mg/L dye concentrations, respectively. A maximum removal of 97% was obtained at natural pH 6.9 for an adsorbent dose of 100 mg/50 mL and 100% removal was obtained for an adsorbent dose of 600 mg/50 mL of 10 mg/L dye concentration. The pH effect and desorption studies suggest that chemisorption might be the major mode of the adsorption process. The change in entropy (DeltaS0) and heat of adsorption (DeltaH0) of coir pith carbon was estimated as 117.20 J/mol/K and 30.88 kJ/mol, respectively. The high negative value of change in Gibbs free energy indicates the feasible and spontaneous adsorption of methylene blue on coir pith carbon.

  11. Reusable nanomaterial and plant biomass composites for the removal of Methylene Blue from water.

    PubMed

    Jain, Nidhi; Basniwal, Rupesh Kumar; Suman; Srivastava, Ashwani Kumar; Jain, Vinod Kumar

    2010-06-01

    A novel composite has been prepared from nanomaterials and powdered orange peel. The composite is adhered to a plastic strip and may be employed for the removal of synthetic dyes from aqueous solutions, for example from dyehouse effluents. Using Methylene Blue (CI Basic Blue 9) as the reference dye, the characteristics of the adsorbent have been studied. The effect of pH, type of nanomaterial (e.g. carbon nanotubes, activated carbon nanotubes, or titanium dioxide nanoparticles), contact time, and reusability have each been investigated. The results show that the adsorption capacity of suspended orange peel powder, an orange peel strip, and an activated carbon nanotube/orange peel strip were 46%, 67% and 78%, respectively. The uptake of dye was greatly affected by the pH of the solution, maximum absorption being obtained at pH 10, and none at all at pH 2. The improved performance was probably the result of the increased area available for adsorption compared with orange peel powder alone. The system was found to be reusable for up to six cycles without appreciable loss of adsorption and desorption efficiency. The nanomaterial in the composite enhanced performance, not only by increasing adsorption efficiency but also by inhibiting biodegradation of the orange peel powder, thereby increasing the life of the strips. The system offers an economical, user-friendly, efficient and reusable adsorption treatment for the removal of dyes from wastewater.

  12. Dyeing and antibacterial activation with methylene blue of a cyclodextrin modified polyester vascular graft.

    PubMed

    Kacem, I; Laurent, T; Blanchemain, N; Neut, C; Chai, F; Haulon, S; Hildebrand, H F; Martel, B

    2014-09-01

    The aim of this study was to develop an antiseptic and blue dyed polyester (PET) vascular graft in order to reach two distinct properties: (i) the prevention of postoperative infections, (ii) the improvement of the graft compatibility with the coelioscopy surgical technique. This work consisted of dyeing a vascular prosthesis with methylene blue (MB) which is known as a cationic dye with antiseptic properties. Therefore, the functionalization of the PET fibers of the prosthesis with a cyclodextrin-citric acid polymer (PolyCD) was achieved in order to improve its sorption capacity. The NMR experiments demonstrated that a 1:2 complex occurred between hydroxypropyl β-cyclodextrin (HP-βCD) and MB. Kinetic and sorption isotherm studies showed that an impregnation of the polyCD modified prosthesis (PET-CD) in a 1 g L(-1) of MB solution for 150 min was sufficient to reach the saturation of the device. Results proved that the adsorption mechanism followed the Langmuir model and a maximum of 20 mg g(-1) of MB on the graft. A sustained release of MB in batch tests was observed in PBS and in vitro microbiological assays displayed a prolongation of the bactericidal effect of PET-CD whose extent varied with the amount of MB preliminarily adsorbed onto the PET-CD.

  13. Pump-probe optical coherence tomography using microencapsulated methylene blue as a contrast agent (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Kim, Wihan; Zebrowski, Erin; Lopez, Hazel C.; Applegate, Brian E.; Charoenphol, Phapanin; Jo, Javier A.

    2016-03-01

    Molecular contrast imaging can target specific molecules or receptors to provide detailed information on the local biochemistry and yield enhanced visualization of pathological and physiological processes. When paired with Optical Coherence Tomography (OCT) it can simultaneously supply the morphological context for the molecular information. We recently demonstrated in vivo molecular contrast imaging of methylene blue (MB) using a 663 nm diode laser as a pump in a Pump-Probe OCT (PPOCT) system. The simple addition of a dichroic mirror in the sample arm enabled PPOCT imaging with a typical 830-nm band spectral-domain OCT system. Here we report on the development of a microencapsulated MB contrast agent. The poly lactic-co-glycolic acid (PLGA) microspheres loaded with MB offer several advantages over bare MB. The microsphere encapsulation improves the PPOCT signal both by enhancing the scattering and preventing the reduction of MB to leucomethylene blue. The surface of the microsphere can readily be functionalized to enable active targeting of the contrast agent without modifying the excited state dynamics of MB that enable PPOCT imaging. Both MB and PLGA are used clinically. PLGA is FDA approved and used in drug delivery and tissue engineering applications. 2.5 μm diameter microspheres were synthesized with an inner core containing 0.01% (w/v) aqueous MB. As an initial demonstration the MB microspheres were imaged in a 100 μm diameter capillary tube submerged in a 1% intralipid emulsion.

  14. Improving the performance of methylene blue sensitized photopolymer by doping with nickel ion

    NASA Astrophysics Data System (ADS)

    Aswathy, G.; Rajesh, C. S.; Sreekumar, K.; Joseph, R.; Kartha, C. Sudha

    2016-05-01

    Holographic performance of an economically cheap metal ion doped photopolymer material is presented. We investigated the effect of incorporation of nickel ion into the methylene blue sensitized poly (vinyl alcohol)/acrylamide (MBPVA/AA) photopolymer system. The composition and preliminary characterization of the developed photopolymer material is reported. The presence of nickel ion improves the diffraction efficiency, stability of the material and it operates in a wide range of spatial frequencies (550-2000 lines/mm) at exposure energy of 100 mJ/cm2. When nickel ion concentration was 0.01 mM, maximum diffraction efficiency of 84% at exposure energy of 100 mJ/cm2 with spatial frequency 1335 lines/mm could be achieved for gratings recorded using wavelength of 632.8 nm. The material showed panchromaticity with more than 70% diffraction efficiency in both blue and green regions. Effects of humidity and temperature on the stored gratings were studied by keeping films in different environmental conditions. Suitability of recording large area holograms was also explored.

  15. Papain gel containing methylene blue for simultaneous caries removal and antimicrobial photoinactivation against Streptococcus mutans biofilms.

    PubMed

    Silva, Zenildo Santos; Huang, Ying-Ying; de Freitas, Lucas Freitas; França, Cristiane Miranda; Botta, Sergio Brossi; Ana, Patrícia Aparecida; Mesquita-Ferrari, Raquel Agnelli; Santos Fernandes, Kristianne Porta; Deana, Alessandro; Lima Leal, Cintia Raquel; Prates, Renato Araujo; Hamblin, Michael R; Bussadori, Sandra Kalil

    2016-09-19

    This study intended to evaluate the effects of a papain-gel with a red-light absorbing pigment (methylene blue - MB) to mediate photodynamic therapy (PDT) against Streptococcus mutans biofilms. The PapaMBlue was compared with free MB to generate reactive oxygen species using fluorescence probes (SOSG and HPF). PDT (660-nm light) was carried out against S. mutans biofilms grown on either plastic dishes or on collagen membrane and assayed by CFU, live-dead staining using confocal microscopy, transmission electron microscopy and H&E staining for collagen films. Cytotoxicity and subcellular localization was studied in human fibroblasts. Sponges of bioabsorbable type I collagen membrane were exposed to papain based gel, irradiated with laser and analyzed about their integrity by ATR-FTIR. The PapaMBlue produced higher amounts of singlet oxygen and hydroxyl radicals than free MB, possibly due to better disaggregation of the dye in solution. The PapaMBlue antimicrobial effects on biofilms proved to be capable of reducing the S. mutans. Both MTT and PrestoBlue assays showed higher cell viability and metabolism scores in fibroblasts treated with PapaMBlue and MB, possibly due to stimulation of mitochondrial activity and that collagen triple helix is unaffected. The PapaMBlue is equally effective as MB in destroying S. mutans biofilms growing on plastic or collagen without affecting fibroblasts.

  16. Spectroscopic investigation of colloidal CdS quantum dots-methylene blue hybrid associates

    NASA Astrophysics Data System (ADS)

    Ovchinnikov, Oleg V.; Smirnov, Michail S.; Shatskikh, Tamara S.; Khokhlov, Vladimir Yu.; Shapiro, Boris I.; Vitukhnovsky, Alexey G.; Ambrozevich, Sergey A.

    2014-03-01

    Spectral properties of hydrophilic associates of colloidal CdS quantum dots (QDs) with methylene blue molecules (MB) prepared by sol-gel method have been studied. The two basic types of hybrid associates were found using FTIR spectra technique. The first-type associates are characterized by planar location of MB heterocycle on QDs spherical interface. In this case MB dimerization is not observed. Both nitrogen and sulfur heteroatoms and double =N+-(CH3)2 bonds of MB are participants of association which causes to conformation of MB heterocycle and π-conjugation length decrease. In UV-Vis absorption and luminescence spectra blue shift of MB peaks for QD-MB associates in comparison with MB spectra in solutions and gelatin was found. The second type of association mostly involves MB nitrogen heteroatoms and CdS QDs interface atoms. At the same time, peaks of UV-Vis and luminescence spectra are red shifted. In this case, dimerization manifestation of MB in QD-MB associates was found. Using the time correlated single photon counting technique resonance electronic excitation energy transfer from recombination luminescence center of CdS QDs to MB molecules was found. Its efficiency is in the range of 0.36-0.51.

  17. Papain gel containing methylene blue for simultaneous caries removal and antimicrobial photoinactivation against Streptococcus mutans biofilms

    PubMed Central

    Silva Jr., Zenildo Santos; Huang, Ying-Ying; de Freitas, Lucas Freitas; França, Cristiane Miranda; Botta, Sergio Brossi; Ana, Patrícia Aparecida; Mesquita-Ferrari, Raquel Agnelli; Santos Fernandes, Kristianne Porta; Deana, Alessandro; Lima Leal, Cintia Raquel; Prates, Renato Araujo; Hamblin, Michael R.; Bussadori, Sandra Kalil

    2016-01-01

    This study intended to evaluate the effects of a papain-gel with a red-light absorbing pigment (methylene blue – MB) to mediate photodynamic therapy (PDT) against Streptococcus mutans biofilms. The PapaMBlue was compared with free MB to generate reactive oxygen species using fluorescence probes (SOSG and HPF). PDT (660-nm light) was carried out against S. mutans biofilms grown on either plastic dishes or on collagen membrane and assayed by CFU, live-dead staining using confocal microscopy, transmission electron microscopy and H&E staining for collagen films. Cytotoxicity and subcellular localization was studied in human fibroblasts. Sponges of bioabsorbable type I collagen membrane were exposed to papain based gel, irradiated with laser and analyzed about their integrity by ATR-FTIR. The PapaMBlue produced higher amounts of singlet oxygen and hydroxyl radicals than free MB, possibly due to better disaggregation of the dye in solution. The PapaMBlue antimicrobial effects on biofilms proved to be capable of reducing the S. mutans. Both MTT and PrestoBlue assays showed higher cell viability and metabolism scores in fibroblasts treated with PapaMBlue and MB, possibly due to stimulation of mitochondrial activity and that collagen triple helix is unaffected. The PapaMBlue is equally effective as MB in destroying S. mutans biofilms growing on plastic or collagen without affecting fibroblasts. PMID:27641507

  18. Microwave-assisted synthesis of reduced graphene oxide/titania nanocomposites as an adsorbent for methylene blue adsorption

    NASA Astrophysics Data System (ADS)

    Wang, Huan; Gao, Haihuan; Chen, Mingxi; Xu, Xiaoyang; Wang, Xuefang; Pan, Cheng; Gao, Jianping

    2016-01-01

    In this study microwave-assisted reduction (MrGO) and direct reduction of graphene oxide (rGO) by Ti powders were established, and the effect of the reaction conditions on the reduction were discussed. The results showed that GO can be effectively reduced by both methods, however, microwave assistance can greatly shorten the reduction time. The produced Ti ions from the reaction of Ti powder with GO were transferred to TiO2 by hydrolysis and formed MrGO/TiO2 and rGO/TiO2. They were used as adsorbents for the removal of methylene blue (MB). MrGO/TiO2 showed a higher adsorption capacity (qmax, 845.6 mg/g) than rGO/TiO2 (qmax, 467.6 mg/g). Investigation on the adsorption MB onto MrGO/TiO2 was conducted and demonstrated that adsorption kinetics followed the pseudo second-order kinetics model and the adsorption isotherm was well described by the Langmuir isotherm model. The recycling of MrGO/TiO2 was achieved by photocatalytic degradation of MB catalyzed by MrGO/TiO2 itself.

  19. Efficient Sunlight-Induced Methylene Blue Removal over One-Dimensional Mesoporous Monoclinic BiVO4 Nanorods

    PubMed Central

    Hou, Linrui; Yang, Long; Li, Jiaoyang; Tan, Jie; Yuan, Changzhou

    2012-01-01

    Sunlight-driven mesoporous BiVO4 nanorods with monoclinic structure have been successfully synthesized via a simple hydrothermal method. The as-prepared one-dimensional BiVO4 nanorods exhibited high specific surface area due to their unique mesoporous structure. The mesoporous BiVO4 nanorods possessed strong photoabsorption properties in the visible light region as well as the ultravisible region, and the band gap was estimated to be ca. 2.18 eV. The photocatalytic activities were evaluated by decolorization of methylene blue under sunlight irradiation. Photocatalytic tests demonstrated that the decolorization rate of as-prepared mesoporous BiVO4 nanorods was even up to 98.8% in 180 min, much better than that prepared by solid-state reaction (23.1%) and the commercial TiO2 (Degussa P25) (14.2%) under the same conditions, due to their higher specific surface area and appropriate band gap. Moreover, the unique BiVO4 nanorods exhibit high stability after five photocatalytic degradation recycles. PMID:22567556

  20. Efficient Sunlight-Induced Methylene Blue Removal over One-Dimensional Mesoporous Monoclinic BiVO(4) Nanorods.

    PubMed

    Hou, Linrui; Yang, Long; Li, Jiaoyang; Tan, Jie; Yuan, Changzhou

    2012-01-01

    Sunlight-driven mesoporous BiVO(4) nanorods with monoclinic structure have been successfully synthesized via a simple hydrothermal method. The as-prepared one-dimensional BiVO(4) nanorods exhibited high specific surface area due to their unique mesoporous structure. The mesoporous BiVO(4) nanorods possessed strong photoabsorption properties in the visible light region as well as the ultravisible region, and the band gap was estimated to be ca. 2.18 eV. The photocatalytic activities were evaluated by decolorization of methylene blue under sunlight irradiation. Photocatalytic tests demonstrated that the decolorization rate of as-prepared mesoporous BiVO(4) nanorods was even up to 98.8% in 180 min, much better than that prepared by solid-state reaction (23.1%) and the commercial TiO(2) (Degussa P25) (14.2%) under the same conditions, due to their higher specific surface area and appropriate band gap. Moreover, the unique BiVO(4) nanorods exhibit high stability after five photocatalytic degradation recycles.

  1. Computed tomography guided percutaneous injection of a mixture of lipiodol and methylene blue in rabbit lungs: evaluation of localization ability for video-assisted thoracoscopic surgery.

    PubMed

    Jin, Kwang Nam; Lee, Kyung Won; Kim, Tae Jung; Song, Yong Sub; Kim, Dong Il

    2014-01-01

    Preoperative localization is necessary prior to video assisted thoracoscopic surgery for the detection of small or deeply located lung nodules. We compared the localization ability of a mixture of lipiodol and methylene blue (MLM) (0.6 mL, 1:5) to methylene blue (0.5 mL) in rabbit lungs. CT-guided percutaneous injections were performed in 21 subjects with MLM and methylene blue. We measured the extent of staining on freshly excised lung and evaluated the subjective localization ability with 4 point scales at 6 and 24 hr after injections. For MLM, radio-opacity was evaluated on the fluoroscopy. We considered score 2 (acceptable) or 3 (excellent) as appropriate for localization. The staining extent of MLM was significantly smaller than methylene blue (0.6 vs 1.0 cm, P<0.001). MLM showed superior staining ability over methylene blue (2.8 vs 2.2, P=0.010). Excellent staining was achieved in 17 subjects (81%) with MLM and 8 (38%) with methylene blue (P=0.011). An acceptable or excellent radio-opacity of MLM was found in 13 subjects (62%). An appropriate localization rate of MLM was 100% with the use of the directly visible ability and radio-opacity of MLM. MLM provides a superior pulmonary localization ability over methylene blue.

  2. Computed Tomography Guided Percutaneous Injection of a Mixture of Lipiodol and Methylene Blue in Rabbit Lungs: Evaluation of Localization Ability for Video-Assisted Thoracoscopic Surgery

    PubMed Central

    Jin, Kwang Nam; Kim, Tae Jung; Song, Yong Sub; Kim, Dong Il

    2014-01-01

    Preoperative localization is necessary prior to video assisted thoracoscopic surgery for the detection of small or deeply located lung nodules. We compared the localization ability of a mixture of lipiodol and methylene blue (MLM) (0.6 mL, 1:5) to methylene blue (0.5 mL) in rabbit lungs. CT-guided percutaneous injections were performed in 21 subjects with MLM and methylene blue. We measured the extent of staining on freshly excised lung and evaluated the subjective localization ability with 4 point scales at 6 and 24 hr after injections. For MLM, radio-opacity was evaluated on the fluoroscopy. We considered score 2 (acceptable) or 3 (excellent) as appropriate for localization. The staining extent of MLM was significantly smaller than methylene blue (0.6 vs 1.0 cm, P<0.001). MLM showed superior staining ability over methylene blue (2.8 vs 2.2, P=0.010). Excellent staining was achieved in 17 subjects (81%) with MLM and 8 (38%) with methylene blue (P=0.011). An acceptable or excellent radio-opacity of MLM was found in 13 subjects (62%). An appropriate localization rate of MLM was 100% with the use of the directly visible ability and radio-opacity of MLM. MLM provides a superior pulmonary localization ability over methylene blue. PMID:24431917

  3. Color measurement of methylene blue dye/clay mixtures and its application using economical methods

    NASA Astrophysics Data System (ADS)

    Milosevic, Maja; Kaludjerovic, Lazar; Logar, Mihovil

    2016-04-01

    Identifying the clay mineral components of clay materials by staining tests is rapid and simple, but their applicability is restricted because of the mutual interference of the common components of clay materials and difficulties in color determination. The change of color with concentration of the dye is related to the use of colorants as a field test for identifying clay minerals and has been improved over the years to assure the accuracy of the tests (Faust G. T., 1940). The problem of measurement and standardization of color may be solved by combination of colors observed in staining tests with prepared charts of color chips available in the Munsell Book of Color, published by Munsell Color Co. Under a particular set of illumination conditions, a human eye can achieve an approximate match between the color of the dyed clay sample and that of a standard color chip, even though they do have different spectral reflectance characteristics. Experiments were carried out with diffuse reflectance spectroscopy on selected clay samples (three montmorillonite, three kaolinite and one mix-layer clay samples) saturated with different concentration of methylene blue dye solution. Dominant wavelength and purity of the color was obtained on oriented dry samples and calculated by use of the I. C. I. (x, y) - diagram in the region of 400-700 nm (reflectance spectra) without MB and after saturation with different concentrations of MB solutions. Samples were carefully photographed in the natural light environment and processed with user friendly and easily accessible applications (Adobe color CC and ColorHexa encyclopedia) available for android phones or tablets. Obtained colors were compared with Munsell standard color chips, RGB and Hexa color standards. Changes in the color of clay samples in their interaction with different concentration of the applied dye together with application of economical methods can still be used as a rapid fieldwork test. Different types of clay

  4. DNA-based biosensors for Hg(2+) determination by polythymine-methylene blue modified electrodes.

    PubMed

    Tortolini, Cristina; Bollella, Paolo; Antonelli, Marta Letizia; Antiochia, Riccarda; Mazzei, Franco; Favero, Gabriele

    2015-05-15

    In this work we have developed a new electrochemical DNA-based biosensor for the selective determination of the Hg(2+) ion by the use of different electrodes modified with polythymine, bearing methylene blue, as redox probe, in 3' position. The determination of Hg(2+) can be employed with an excellent degree of selectivity by the use of DNA biosensors through the formation of the complex Thymine-Hg-Thymine (T-Hg-T): in fact, Hg(2+) tends to bind two thymines, generating a T-Hg-T complex with a formation constant higher than that one of the coupling Adenine-Thymine, which can be employed for a selective, fast and cost-effective Hg(2+) detection. The presence of the Hg(2+) in solution leads to the formation of T-Hg-T complex thus causing the "hairpin-like" folding of oligonucleotide, leading to an improved electronic exchange of methylene blue with the electrode surface due to the reduced distance and thus to an increase of the faradic current which is detected by means of square wave voltammetry (SWV). To test the feasibility of this kind of biosensor to be applied to the analysis of Hg(2+) we have developed several biosensors configuration by modifying the electrochemical sensor transducer: (a) Au electrode; (b) Au screen-printed electrode (SPE). The proposed system, allows the determination of Hg(2+) in the range 0.2-100 nM (0.05-20 ppb), with a sensitivity 0.327 µA/nM, LOD 0.1 nM (0.02 ppb), LOQ 0.2 nM (0.05 ppb) and RSD ≤4.3% when Au electrode is used as electrochemical transducer; on the other hand, in the case of Au SPE the linear range is 0.2-50 nM (0.05-10 ppb), with a sensitivity 0.285 µA/nM, while LOD and LOQ are the same as previously and RSD is ≤3.8%. This enabled the detection of mercury in real samples (waters and fishes) with good accuracy (recoveries 92-101% on waters and 92-107% on fishes, respectively) and reproducibility (RSD ≤9.6% for measurements on waters and ≤8.8% on fishes, respectively).

  5. The interactions of azure B, a metabolite of methylene blue, with acetylcholinesterase and butyrylcholinesterase

    SciTech Connect

    Petzer, Anél; Harvey, Brian H.; Petzer, Jacobus P.

    2014-02-01

    Methylene blue (MB) is reported to possess diverse pharmacological actions and is attracting increasing attention for the treatment of neurodegenerative disorders such as Alzheimer's disease. Among the pharmacological actions of MB, is the significant inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). These activities may, at least in part, underlie MB's beneficial effects in Alzheimer's disease. MB is metabolized to yield N-demethylated products of which azure B, the monodemethyl metabolite, is the predominant species. Azure B has been shown to be pharmacologically active and also possesses a variety of biological actions. Azure B therefore may contribute to the pharmacological profile of MB. Based on these considerations, the present study investigates the possibility that azure B may, similar to MB, act as an inhibitor of human AChE and BuChE. The results document that azure B inhibits AChE and BuChE with IC{sub 50} values of 0.486 μM and 1.99 μM, respectively. The results further show that azure B inhibits AChE and BuChE reversibly, and that the modes of inhibition are most likely competitive. Although the AChE and BuChE inhibitory activities of azure B are twofold and fivefold, respectively, less potent than those recorded for MB [IC{sub 50}(AChE) = 0.214 μM; IC{sub 50}(BuChE) = 0.389 μM] under identical conditions, azure B may be a contributor to MB's in vivo activation of the cholinergic system and beneficial effects in Alzheimer's disease. - Highlights: • Methylene blue (MB) is a known inhibitor of AChE and BuChE. • Azure B, the major metabolite of MB, also is an inhibitor of AChE and BuChE. • Azure B may be a contributor to MB's in vivo activation of the cholinergic system. • Azure B may contribute to MB's potential in Alzheimer's disease therapy.

  6. Interactions of Methylene Blue with Human Disulfide Reductases and Their Orthologues from Plasmodium falciparum▿

    PubMed Central

    Buchholz, Kathrin; Schirmer, R. Heiner; Eubel, Jana K.; Akoachere, Monique B.; Dandekar, Thomas; Becker, Katja; Gromer, Stephan

    2008-01-01

    Methylene blue (MB) has experienced a renaissance mainly as a component of drug combinations against Plasmodium falciparum malaria. Here, we report biochemically relevant pharmacological data on MB such as rate constants for the uncatalyzed reaction of MB at pH 7.4 with cellular reductants like NAD(P)H (k = 4 M−1 s−1), thioredoxins (k = 8.5 to 26 M−1 s−1), dihydrolipoamide (k = 53 M−1 s−1), and slowly reacting glutathione. As the disulfide reductases are prominent targets of MB, optical tests for enzymes reducing MB at the expense of NAD(P)H under aerobic conditions were developed. The product leucomethylene blue (leucoMB) is auto-oxidized back to MB at pH 7 but can be stabilized by enzymes at pH 5.0, which makes this colorless compound an interesting drug candidate. MB was found to be an inhibitor and/or a redox-cycling substrate of mammalian and P. falciparum disulfide reductases, with the kcat values ranging from 0.03 s−1 to 10 s−1 at 25°C. Kinetic spectroscopy of mutagenized glutathione reductase indicates that MB reduction is conducted by enzyme-bound reduced flavin rather than by the active-site dithiol Cys58/Cys63. The enzyme-catalyzed reduction of MB and subsequent auto-oxidation of the product leucoMB mean that MB is a redox-cycling agent which produces H2O2 at the expense of O2 and of NAD(P)H in each cycle, turning the antioxidant disulfide reductases into pro-oxidant enzymes. This explains the terms subversive substrate or turncoat inhibitor for MB. The results are discussed in cell-pathological and clinical contexts. PMID:17967916

  7. Simultaneous adsorption of methyl red and methylene blue onto biochar and an equilibrium modeling at high concentration.

    PubMed

    Ding, Guanyu; Wang, Buyun; Chen, Lingyu; Zhao, Shuangjiao

    2016-11-01

    Methyl red, methylene blue and biochar were used to investigate simultaneous adsorption of dyes onto low-cost adsorbent at different concentrations combinations. Langmuir mixed model could describe the adsorption well at low concentrations. However, it could not describe the adsorption anymore when concentrations of methyl red and methylene blue were higher than 255 and 300 mg L(-1) respectively with 0.5 g L(-1) biochar loading. A new model on the interaction among adsorbed adsorbates at equilibrium was developed. It could describe the adsorption at high concentrations well. According to the experimental results, interaction among dyes molecules would replace the competition onto adsorbent to be the main factor influencing adsorption when amount of adsorbed adsorbates were higher than those required to form a monolayer on all the adsorbing sites of adsorbent. The model was further verified by adsorption with other solute such as glucose or NaCl in solution.

  8. Use of methylene blue as a simulant for the physical properties of cocaine HCl and heroin HCl

    NASA Astrophysics Data System (ADS)

    Patrick, Julie C.; Orzechowska, Grazyna E.; Poziomek, Edward J.

    1997-02-01

    Technological challenges in the development and testing of illicit narcotics include assuring safety of researchers and operations personnel from drug exposure, assessing the efficiency of sampling and sample handling, checking for artifacts introduced by field procedures, and maintaining quality control/quality assurance. The dye methylene blue was chosen as a simulant for cocaine HCl and heroin HCl. The similarities include the presence of fused ring systems, molecular weights over 300 g/mol, and melting points between 200 and 300 degrees C. A significant difference is that methylene blue has a much lower solubility in water than cocaine HCl and heroin HCl. Experiments have been conducted to successfully increase the solubility of the simulant to match those of cocaine HCl and heroin HCl by adding solidum methyl sulfate.

  9. One-pot preparation of superparamagnetic attapulgite/Fe3O4/polydopamine nanocomposites for adsorption of methylene blue

    NASA Astrophysics Data System (ADS)

    Mu, Bin; Kang, Yuru; Zheng, Maosong; Wang, Aiqin

    2016-05-01

    Superparamagnetic attapulgite/Fe3O4/polydopamine nanocomposites have been facilely prepared by a one-pot process without the nitrogen protection, in which Fe(III) was served as both of the oxidant for dopamine and the precursor of Fe3O4 in the presence of attapulgite. The introduction of attapulgite can effectively induce the uniform encapsulation of polydopamine and Fe3O4 nanoparticles on the surface of attapulgite, preventing from the formation of the free aggregates of Fe3O4 nanoparticles. The as-prepared APT/Fe3O4/PANI nanocomposites can be used as an adsorbent for the removal of methylene blue, and the adsorption ratio toward 100 ppm of methylene blue could reach 95.8%.

  10. Methylene blue adsorption onto swede rape straw (Brassica napus L.) modified by tartaric acid: equilibrium, kinetic and adsorption mechanisms.

    PubMed

    Feng, Yanfang; Zhou, Hui; Liu, Guohua; Qiao, Jun; Wang, Jinhua; Lu, Haiying; Yang, Linzhang; Wu, Yonghong

    2012-12-01

    The aim of this study was to develop a promising and competitive bioadsorbent with the abundant of source, low price and environmentally friendly characters to remove cationic dye from wastewater. The swede rape straw (Brassica napus L.) modified by tartaric acid (SRSTA) was prepared, characterized and used to remove methylene blue (MB) from aqueous solution at varied operational conditions (including MB initial concentrations, adsorbent dose, etc.). Results demonstrated that the equilibrium data was well fitted by Langmuir isotherm model. The maximum MB adsorption capacity of SRSTA was 246.4 mg g(-1), which was comparable to the results of some previous studied activated carbons. The higher dye adsorption capacity could be attributed to the presence of more functional groups such as carboxyl group on the surface of SRSTA. The adsorption mechanism was also discussed. The results indicate that SRSTA is a promising and valuable absorbent to remove methylene blue from wastewater.

  11. Adsorption of methylene blue on raw and MTZ/imogolite hybrid surfaces: effect of concentration and calorimetric investigation.

    PubMed

    Guerra, Denis L; Batista, Adriano C; Viana, Rúbia R; Airoldi, Claudio

    2010-11-15

    The synthetic imogolite sample was used for organofunctionalization process with 2-mercaptothiazoline (MTZ). The compound 2-mercaptothiazoline was anchored onto imogolite surface by heterogeneous route. Due to the increment of basic centers attached to the pendant chains the dye adsorption capability of the final chelating material, was found to be higher than is precursor. The ability of these materials to remove methylene blue from aqueous solution was followed by a series of adsorption isotherms at room temperature and pH 4.0. The maximum number of moles adsorbed was determined to be 40.32×10(-2) and 65.13×10(-2) mmol g(-1) for IMO and IMO(MTZ), respectively. The energetic effects caused by dye cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such methylene blue-nitrogen and sulfur interactions.

  12. Single incision laparoscopic surgery approach for obscure small intestine bleeding localized by CT guided percutaneous injection of methylene blue

    PubMed Central

    Martinez, Juan Carlos; Thomas, Jamie L.; Lukaszczyk, John J.

    2014-01-01

    INTRODUCTION Traditionally, localization of small intestine sources of obscure gastrointestinal bleeding has been a challenge. Advances in the field of endoscopy with the introduction of capsule endoscopy and radiographic imaging with computed tomography angiography and visceral angiography have facilitated more accurate visualization of the small intestine. If a bleeding lesion is identified on angiography and surgery is indicated, the use of methylene blue for enteric mapping is very effective to aid intraoperative localization of the culprit. However, when this is not an option, more invasive surgical techniques are required. PRESENTATION OF CASE We present a new technique used in a patient with angiodysplasia of the small intestine, in where preoperative localization was done using percutaneous computed tomography (CT) guided injection of methylene blue dye. This allowed us to perform a single incision laparoscopic small intestine resection of the culprit. PMID:25460480

  13. Distal and lateral toenail onychomycosis caused by Trichophyton rubrum: treatment with photodynamic therapy based on methylene blue dye.

    PubMed

    Souza, Linton Wallis Figueiredo; Souza, Simone Vilas Trancoso; Botelho, Ana Cristina de Carvalho

    2014-01-01

    The study showed the effectiveness of photodynamic therapy based on methylene blue to treat severe distal and lateral subungual toenail onychomycosis. 22 patients were divided into two groups: group A consisting of 11 patients with severe toenail onychomycosis and group B consisting of 11 patients with mild-to-moderate toenail onychomycosis. All patients had onychomycosis caused by Trichophyton rubrum. The patients were treated with sessions of 2% methylene blue aqueous solution irradiated with light emission diode device with 630 nm and 36 J/cm2 biweekly for six months. The clinical response was significantly better in patients with mild-to-moderate (100%) onychomycosis compared with patients with severe onychomycosis (63.6%).

  14. Myoclonus in patient on fluoxetine after receiving fentanyl and low-dose methylene blue during sentinel lymph node biopsy.

    PubMed

    Larson, Kelly J; Wittwer, Erica D; Nicholson, Wayne T; Weingarten, Toby N; Price, Daniel L; Sprung, Juraj

    2015-05-01

    Serotonin released in the nerve synapses is cleared through reuptake into presynaptic neurons and metabolism with monoamine oxidase (MAO). Therapy with selective serotonin reuptake inhibitors (SSRIs) or MAO inhibitors increases serotonin concentration in the synaptic cleft and may result in serotonin syndrome (SS). Our patient undergoing sentinel lymph node biopsy was on fluoxetine (SSRI) and intraoperatively developed SS after receiving fentanyl (200 μg) and methylene blue (MAO inhibitor), 7 mg subcutaneously into the scalp. Initial presentation was several episodes of generalized muscle activity, which was later diagnosed as lower extremity myoclonus consistent with SS. Upon awakening, the patient showed no evidence of encephalopathy, and the clonus was less intense. The patient was discharge home the next day. Our case suggests the possibility that even a small dose of methylene blue, when administered simultaneously with other serotoninergic medications, may be associated with serotonin toxicity.

  15. Studies on the ion-association of methylene blue and salicylic acid in neat and mixed binary solvents

    NASA Astrophysics Data System (ADS)

    Basu, Soumen; Ghosh, Sujit Kumar; Kundu, Subrata; Nath, Sudip; Panigrahi, Sudipa; Praharaj, Snigdhamayee; Pal, Tarasankar

    2005-05-01

    Thiazine dye, methylene blue forms 1:1 ion-associate with salicylic acid in aqueous phase and the ion-associate can be extracted in a series of non-polar non-coordinating solvent systems. The influence of different parameters on the process of ion-association has been studied. The suitability of a number of phenolic precursors for the formation of ion-associate with methylene blue has been tested. Charge-transfer absorption band of the dye molecules in relation to ion-pair has been followed in a sequence of neat and mixed binary solvents and the dependence of the absorption maxima has been found to correlate well with the solvent polarity.

  16. Novelties of combustion synthesized titania ultrafiltration membrane in efficient removal of methylene blue dye from aqueous effluent.

    PubMed

    Doke, Suresh M; Yadav, Ganapati D

    2014-12-01

    In this study, titania nanoparticles were synthesized by combustion and used to make ultrafiltration membrane. Characteristics of titania membranes such as textural evaluation, surface morphology, pure water permeability and protein rejection were investigated. Titania membrane sintered at 450 °C showed pure water permeability 11 × 10−2 L h−1 m−2 kPa−1 and 76% protein rejection. The membrane presented good water flux and retention properties with regards to protein and methylene blue dye. Ultrafiltration process was operated at lower pressure (100 kPa) and showed 99% removal of methylene blue using adsorptive micellar flocculation at sodium dodecyl sulfate concentration below its critical micellar concentration. Ferric chloride was used as the coagulant. The method of making titania membrane and its use are new. These studies can be extended to other dyes and pollutants.

  17. Titanium dioxide-gold nanocomposite materials embedded in silicate sol-gel film catalyst for simultaneous photodegradation of hexavalent chromium and methylene blue.

    PubMed

    Pandikumar, Alagarsamy; Ramaraj, Ramasamy

    2012-02-15

    Aminosilicate sol-gel supported titanium dioxide-gold (EDAS/(TiO(2)-Au)(nps)) nanocomposite materials were synthesized by simple deposition-precipitation method and characterized. The photocatalytic oxidation and reduction activity of the EDAS/(TiO(2)-Au)(nps) film was evaluated using hexavalent chromium (Cr(VI)) and methylene blue (MB) dye under irradiation. The photocatalytic reduction of Cr(VI) to Cr(III) was studied in the presence of hole scavengers such as oxalic acid (OA) and methylene blue (MB). The photocatalytic degradation of MB was investigated in the presence and absence of Cr(VI). Presence of Au(nps) on the (TiO(2))(nps) surface and its dispersion in the silicate sol-gel film (EDAS/(TiO(2)-Au)(nps)) improved the photocatalytic reduction of Cr(VI) and oxidation of MB due to the effective interfacial electron transfer from the conduction band of the TiO(2) to Au(nps) by minimizing the charge recombination process when compared to the TiO(2) and (TiO(2)-Au)(nps) in the absence of EDAS. The EDAS/(TiO(2)-Au)(nps) nanocomposite materials provided beneficial role in the environmental remediation and purification process through synergistic photocatalytic activity by an advanced oxidation-reduction processes.

  18. Novel magnetic porous carbon spheres derived from chelating resin as a heterogeneous Fenton catalyst for the removal of methylene blue from aqueous solution.

    PubMed

    Ma, Junjun; Zhou, Lincheng; Dan, Wenfeng; Zhang, He; Shao, Yanming; Bao, Chao; Jing, Lingyun

    2015-05-15

    Porous magnetic carbon spheres (MCS) were prepared from carbonized chelating resin composites derived from ethylenediaminetetraacetic acid-modified macroporous polystyrene (PS-EDTA) resin, and then loaded with iron composites via ion exchange. The resulting composites were characterized for this study using X-ray diffraction, MÖssbauer spectroscopy, and Raman spectroscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area method, scanning electron microscopy, and vibrating sample magnetometry. The porous magnetic carbon spheres were then used, in the existence of H2O2 and NH2OH, with a view to remove methylene blue from the aqueous solution by catalyze a heterogeneous Fenton reaction. Results indicated excellent removal rates and removal efficiency for this catalytic system. Optimal degradation was achieved (nearly 100% within 10 min) using initial concentrations of 5 mmol H2O2 L(-1), 2.5 mmol L(-1) NH2OH and 40 mg L(-1) methylene blue. The catalyst retained its activity after six reuses, indicating strong stability and reusability. Porosity of the catalyst contributed to its high activity, suggesting its potential application for the industrial treatment of wastewater.

  19. Probing titanate nanowire surface acidity through methylene blue adsorption in colloidal suspension and on thin films.

    PubMed

    Horváth, Endre; Szilágyi, István; Forró, László; Magrez, Arnaud

    2014-02-15

    The interaction of the cationic dye methylene blue (MB) with titanate nanowires (TiONWs) was investigated in different pH environments using visible spectroscopy and electrophoresis on thin films as well as in aqueous suspension. The surface charge of the TiONWs depends on the pH and ionic strength leading to positive charge under acidic and negative under alkaline conditions. The TiONWs have the same adsorption capacity on films and in suspensions at neutral pH while under alkaline conditions they are able to adsorb significantly more MB in suspension due to their higher surface area. Detailed adsorption studies in water revealed that dye cations form monomers, dimers and larger aggregates of H-type (face-to-face) on the TiONW films. The results indicate that below pH = 4.0 the TiONWs' external surface consists of Brøntsted acid sites capable of protonating MB. It was suggested that reversible indicator role of MB molecule dimers probes the TiONW surface acidity (Brøntsted sites).

  20. Synthesis of citric acid functionalized magnetic graphene oxide coated corn straw for methylene blue adsorption.

    PubMed

    Ge, Heyi; Wang, Cuicui; Liu, Shanshan; Huang, Zhen

    2016-12-01

    The citric acid functionalized magnetic graphene oxide coated corn straw (CA-mGOCS) as a new adsorbent was synthesized in this work for the elimination of methylene blue (MB) from waste water. The as-prepared CA-mGOCS was tested by SEM, FTIR, XRD, Roman spectrum, TGA, particle size analyzer, BET and magnetic properties analyzer. Some factors affecting adsorption removal efficiency were explored. As a result, the addition of 5g CS (CA-mGO5CS) had the better adsorption performance than other adsorbents. The pseudo-second-order model and the Freundlich described the adsorption behavior well. The equilibrium adsorption capacity was 315.5mgg(-1) for MB at pH=12 and 298k. The electrostatic incorporation as well as hydrophobic interactions between CA-mGO5CS and MB determined the favourable adsorption property. Besides, the thermodynamic studies results ΔG<0, ΔH<0, ΔS<0 suggested that the adsorption was a spontaneous, exothermic and randomness decrease process. Finally, reusability studies imply that CA-mGO5CS has an excellent reproducibility.

  1. Adsorption of methylene blue on biochar microparticles derived from different waste materials.

    PubMed

    Lonappan, Linson; Rouissi, Tarek; Das, Ratul Kumar; Brar, Satinder K; Ramirez, Antonio Avalos; Verma, Mausam; Surampalli, Rao Y; Valero, José R

    2016-03-01

    Biochar microparticles were prepared from three different types of biochar, derived from waste materials, such as pine wood (BC-PW), pig manure (BC-PM) and cardboard (BC-PD) under various pyrolysis conditions. The microparticles were prepared by dry grinding and sequential sieving through various ASTM sieves. Particle size and specific surface area were analyzed using laser particle size analyzer. The particles were further characterized using scanning electron microscope (SEM). The adsorption capacity of each class of adsorbent was determined by methylene blue adsorption tests in comparison with commercially available activated carbon. Experimental results showed that dye adsorption increased with initial concentration of the adsorbate and biochar dosage. Biochar microparticles prepared from different sources exhibited improvement in adsorption capacity (7.8±0.5 mg g(-1) to 25±1.3 mg g(-1)) in comparison with raw biochar and commercially available activated carbon. The adsorption capacity varied with source material and method of production of biochar. The maximum adsorption capacity was 25 mg g(-1) for BC-PM microparticles at 25°C for an adsorbate concentration of 500 mg L(-1) in comparison with 48.30±3.6 mg g(-1) for activated carbon. The equilibrium adsorption data were best described by Langmuir model for BC-PM and BC-PD and Freundlich model for BC-PW.

  2. Adsorption of methylene blue using modified adsorbents from drinking water treatment sludge.

    PubMed

    Nageeb Rashed, M; El-Daim El Taher, M A; Fadlalla, Somaya M M

    2016-10-01

    This study aims to explore the preparation and application of alum sludge (AS) and mud sludge (MS) from a drinking water treatment plant to remove methylene blue (MB) dye from aqueous solution. The sludge (MS and AS) was treated by chemical and physical activation to obtain new adsorbents. The adsorption experiments were carried out under different conditions of initial dye concentration (50-100 mg/L) adsorbent dosage (0.05-0.25 g), solution pH (3-9), temperature (20-60 °C) and contact time (20-90 min). Scanning electron microscopy (SEM) and X-ray diffraction instruments were used for characterization of the developed adsorbents. The results show that sludge activated by nitric acid (0.25 M HNO3) and pyrolysis at 700 °C were the best chemically and physically activated adsorbents. The optimum adsorption conditions for the adsorption of MB are 100 ppm initial dye concentration, 1 hour contact time, 250 °C solution temperature, pH 7 and 0.25 g adsorbent dosage. Application of the Langmuir and Freundlich Isotherm models showed that adsorbents fitted the Langmuir model well. SEM studies indicated the porous structural aspects of sludge suitable for removing MB dye.

  3. Batch study of liquid-phase adsorption of methylene blue using cedar sawdust and crushed brick.

    PubMed

    Hamdaoui, Oualid

    2006-07-31

    This paper presents a study on the batch adsorption of basic dye, methylene blue, from aqueous solution (40 mg L(-1)) onto cedar sawdust and crushed brick in order to explore their potential use as low-cost adsorbents for wastewater dye removal. Adsorption isotherms were determined at 20 degrees C and the experimental data obtained were modelled with the Langmuir, Freundlich, Elovich and Temkin isotherm equations. Adsorption kinetic data determined at a temperature of 20 degrees C were modelled using the pseudo-first and pseudo-second-order kinetic equations, liquid-film mass transfer and intra-particle diffusion models. By considering the experimental results and adsorption models applied in this study, it can be concluded that equilibrium data were represented well by a Langmuir isotherm equation with maximum adsorption capacities of 142.36 and 96.61 mg g(-1) for cedar sawdust and crushed brick, respectively. The second-order model best describes adsorption kinetic data. Analysis of adsorption kinetic results indicated that both film- and particle-diffusion are effective adsorption mechanisms. The Influence of temperature and pH of the solution on adsorption process were also studied. The extent of the dye removal decreased with increasing the solution temperature and optimum pH value for dye adsorption was observed at pH 7 for both adsorbents. The results indicate that cedar sawdust and crushed brick can be attractive options for dye removal from dilute industrial effluents.

  4. Photosensitization of Aggregatibacter actinomycetemcomitans with methylene blue: a microbiological and spectroscopic study

    NASA Astrophysics Data System (ADS)

    Yamada Júnior, Aécio M.; Prates, Renato A.; Cai, Silvana; Ribeiro, Martha S.

    2008-03-01

    The aim of this study was to determinate the efficiency of methylene blue (MB) to kill cultures of Aggregatibacter actinomycetemcomitans under red light and to investigate MB photobleaching by optical absorption spectroscopy. Bacteria were diluted in aqueous solution, putted in glass tubes and distributed in 5 groups: (L-MB-) control group; (L+MB-) laser alone by 5min; (L-MB+) MB alone through 5min; (3L+MB+) MB+laser 3min; (5L+MB+) MB+laser 5min. Laser parameters were P=30mW, λ=660nm, E=9J in 5min and E=5.4J in 3min. The samples were diluted and bacterial colonies were counted and converted into colony forming units (CFU). Absorption spectra of the MB-stained bacterial suspension and photosensitized bacterial suspension were obtained. Groups L-MB-, L+MB-, and L-MB+ did not show a decrease in CFU/mL. L+MB+ groups showed a significant decrease in CFU/mL but no statistically significant differences were observed between 3min and 5min. Spectroscopy showed that MB is photodegraded after irradiation and that dimer species are more notably consumed than monomeric species. These results suggest that MB is a suitable photosensitizer to reduce A. actinomycetemcomitans, and that 3min of irradiation are enough to produce a significant effect. Due to the spectral changes observed on MB solution after irradiation a type I mechanism may be involved.

  5. Synthesis and characterization of hybrid molecularly imprinted polymer (MIP) membranes for removal of methylene blue (MB).

    PubMed

    Asman, Saliza; Yusof, Nor Azah; Abdullah, Abdul Halim; Haron, Md Jelas

    2012-02-15

    This work reports the synthesis and characterization of a hybrid molecularly imprinted polymer (MIP) membrane for removal of methylene blue (MB) in an aqueous environment. MB-MIP powders were hybridized into a polymer membrane (cellulose acetate (CA) and polysulfone (PSf)) after it was ground and sieved (using 90 µm sieve). MB-MIP membranes were prepared using a phase inversion process. The MB-MIP membranes were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Parameters investigated for the removal of MB by using membrane MB-MIP include pH, effect of time, concentration of MB, and selectivity studies. Maximum sorption of MB by PSf-MB-MIP membranes and CA-MB-MIP membranes occurred at pH 10 and pH 12, respectively. The kinetic study showed that the sorption of MB by MB-MIP membranes (PSf-MB-MIP and CA-MB-MIP) followed a pseudo-second-order-model and the MB sorption isotherm can be described by a Freundlich isotherm model.

  6. Sugarcane bagasse for the removal of erythrosin B and methylene blue from aqueous waste

    NASA Astrophysics Data System (ADS)

    Sharma, Pankaj; Kaur, Harleen

    2011-12-01

    Present study explores the potentiality of locally available cellulose, hemicellulose and lignin-rich agricultural by-product sugarcane bagasse (SB) for the removal of erythrosin B (EB) and methylene blue (MB) from aqueous waste. The SB has been characterized by Fourier transform infrared and scanning electron microscopy analytical techniques. Batch experiments have been carried out to determine the influence of parameters like initial dye concentration, pH of the medium, contact time between the adsorbate and adsorbent, weight of adsorbent and system temperature on the removal of EB and MB. Optimum conditions for adsorption are found to be pH 9, temperature 308 K and an equilibration time of 1 h. Under these conditions equilibrium isotherms have been analysed by Langmuir and Freundlich isotherm equations. Based on the Langmuir adsorption isotherm model, the predicted maximum monolayer adsorption capacities of SB for EB and MB are found to be 500 mg g-1 (at 328 K) and 1,000 mg g-1 (at 308 K), respectively. The separation factor reveals the favourable nature of the isotherm for the studied dyes—SB system. The thermodynamic study indicates that the adsorptions of dyes are spontaneous and endothermic process. High temperatures favour EB adsorption whereas optimum temperature for MB adsorption is 318 K.

  7. The hemodynamic effects of methylene blue when administered at the onset of cardiopulmonary bypass.

    PubMed

    Maslow, Andrew D; Stearns, Gary; Butala, Parag; Batula, Parag; Schwartz, Carl S; Gough, Jeffrey; Singh, Arun K

    2006-07-01

    Hypotension occurs during cardiopulmonary bypass (CPB), in part because of induction of the inflammatory response, for which nitric oxide and guanylate cyclase play a central role. In this study we examined the hemodynamic effects of methylene blue (MB), an inhibitor of guanylate cyclase, administered during cardiopulmonary bypass (CPB) to patients taking angiotensin-converting enzyme inhibitors. Thirty patients undergoing cardiac surgery were randomized to receive either MB (3 mg/kg) or saline (S) after institution of CPB and cardioplegic arrest. CPB was managed similarly for all study patients. Hemodynamic data were assessed before, during, and after CPB. The use of vasopressors was recorded. All study patients experienced a similar reduction in mean arterial blood pressure (MAP) and systemic vascular resistance (SVR) with the onset of CPB and cardioplegic arrest. MB increased MAP and SVR and this effect lasted for 40 minutes. The saline group demonstrated a persistently reduced MAP and SVR throughout CPB. The saline group received phenylephrine more frequently during CPB, and more norepinephrine after CPB to maintain a desirable MAP. The MB group recorded significantly lower serum lactate levels despite equal or greater MAP and SVR. In conclusion, administration of MB after institution of CPB for patients taking angiotensin-converting enzyme inhibitors increased MAP and SVR and reduced the need for vasopressors. Furthermore, serum lactate levels were lower in MB patients, suggesting more favorable tissue perfusion.

  8. The effects of photodynamic treatment with new methylene blue N on the Candida albicans proteome.

    PubMed

    Brancini, Guilherme Thomaz Pereira; Rodrigues, Gabriela Braga; Rambaldi, Mariana de Souza Lima; Izumi, Clarice; Yatsuda, Ana Patrícia; Wainwright, Mark; Rosa, José César; Braga, Gilberto Úbida Leite

    2016-11-30

    Candida albicans is a human pathogenic fungus mainly affecting immunocompromised patients. Resistance to the commonly used fungicides can lead to poor treatment of mucosal infections which, in turn, can result in life-threatening systemic candidiasis. In this scenario, antimicrobial photodynamic treatment (PDT) has emerged as an effective alternative to treat superficial and localized fungal infections. Microbial death in PDT is a consequence of the oxidation of many cellular biomolecules, including proteins. Here, we report a combination of two-dimensional electrophoresis and tandem mass spectrometry to study the protein damage resulting from treating C. albicans with PDT with new methylene blue N and red light. Two-dimensional gels of treated cells showed an increase in acidic spots in a fluence-dependent manner. Amino acid analysis revealed a decrease in the histidine content after PDT, which is one plausible explanation for the observed acidic shift. However, some protein spots remained unchanged. Protein identification by mass spectrometry revealed that both modified and unmodified proteins could be localized to the cytoplasm, ruling out subcellular location as the only explanation for damage selectivity. Therefore, we hypothesize that protein modification by PDT is a consequence of both photosensitizer binding affinity and the degree of exposure of the photooxidizable residues on the protein surface.

  9. The preparation of novel adsorbent materials with efficient adsorption performance for both chromium and methylene blue.

    PubMed

    Li, Leilei; Liu, Feng; Duan, Huimin; Wang, Xiaojiao; Li, Jianbo; Wang, Yanhui; Luo, Chuannan

    2016-05-01

    The hydroxy-functionalized ionic liquids (ILs) modified with magnetic chitosan/grapheneoxide (MG-ILs-OH) were synthesized. The surface morphology of MG-ILs-OH was characterized by transmission electron microscopy, X-ray diffraction, thermo gravimetric analysis and Fourier transform infrared spectroscopy techniques. It was found that the adsorption kinetics is well fitted by a pseudo-second-order model and the adsorption isotherms agree well with the Langmuir model, and the MG-ILs-OH could be repeatedly used by simple treatment. The results showed that the addition of ILs-OH can largely increase the adsorption sites (hydroxy and amino groups) and adsorption properties. The MG-ILs-OH were used as adsorbent for the removal of methylene blue (MB) and Cr(VI) from simulated wastewater with a fast solid-liquid separation in the presence of external magnetic field. The maximum obtained adsorption capacities of MB and Cr(VI) were 243.31 and 107.99 mg/g, respectively. The application of MG-ILs-OH could effectively solve the problem that the adsorbent only adsorb similar adsorbate.

  10. Preparation, Characterization and Methylene Blue Dye Adsorption Ability of Acid Activated-Natural Zeolite

    NASA Astrophysics Data System (ADS)

    Saputra, O. A.; Prameswari, M. D.; Kinanti, V. T. D.; Mayasari, O. D.; Sutarni, Y. D.; Apriany, K.; Lestari, W. W.

    2017-02-01

    The aim of this research was to prepare an acid-activated natural zeolite (Ac-Zeo) as a low-cost adsorbent material and to investigate their ability on methylene blue dye removal in aqueous solution. The natural zeolite was activated using hydrochloric acid and the final product was characterized using Fourier transform infra-red (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The adsorption process was carried out using the batch method. Some parameters like pH condition, contact time and varied dye initial concentration were studied to determine the adsorption ability of Ac-Zeo. In this study, kinetic adsorption was evaluated using pseudo-second order model approach and found that the kinetic adsorption rate constanta (k) and adsorption capacity at equilibrium are 0.1872 mg.g-1.min-1 and 14.94 mg.g-1, respectively. Moreover, Langmuir, Freundlich, and Dubinin–Kaganer–Radushkevich isotherm adsorption models as well as sorption mechanism were studied in this research.

  11. Removal of methylene blue from aqueous solutions by chemically modified bamboo.

    PubMed

    Guo, Jian-Zhong; Li, Bing; Liu, Li; Lv, Kangle

    2014-09-01

    Chemically modified bamboo (CMB) was utilized for removing methylene blue (MB) from aqueous media in the present study. The adsorbent was characterized by Fourier transform infrared (FTIR) spectra and elemental analysis, which confirms that carboxyl groups and diethylenetriamine were successfully introduced into the surface of bamboo. The effects of initial MB concentration (100-900mgL(-1)), contact time (15-315min), the pH of the solution (3-10), temperature (298-318K), adsorbent dosage (0.4-2.6gL(-1)) and salt concentration on the adsorption efficiency of CMB towards MB were investigated. It was found that the adsorption of MB in CMB fits Langmuir mode well, and the maximum adsorption capacity of CMB achieved 606mgg(-1) at 298K, which is much higher than those obtained from previously investigated bioadsorbents. The adsorption kinetics can be described by pseudo-second-order kinetic model, and the adsorption of MB on CMB was an exothermic process. The results of the present study suggest that CMB is an effective biosorbent for removal of organic pollutants from aqueous solutions.

  12. Kinetics of competitive adsorption of β-casein and methylene blue on hydrophilic glass.

    PubMed

    Qi, Zhi-mei; Lu, Dan-feng; Deng, Lin; Matsuda, Naoki

    2012-03-08

    The competitive adsorption of methylene blue (MB) and β-casein on hydrophilic glass from an aqueous mixed solution was directly detected at the solution pH smaller than the protein isoelectric point (pI) by means of the waveguide-based broadband time-resolved evanescent wave absorption spectroscopy. The competitive adsorption causes the MB coverage to exponentially decrease with time from its peak value and prevents MB aggregation at the interface. The kinetic equation for the competitive adsorption of binary adsorbates was theoretically deduced based on the Langmuir model, and was used for creating the best fit to the experimental data. In the case of a fixed concentration of MB in the mixed solution, the best-fit parameter τ(-1) increases with the protein concentration at a specific pH and decreases with the solution pH at a given concentration of protein. The findings suggest that the β-casein concentration in sub-μM level can be rapidly determined by the time-resolved waveguide absorptiometry based on the competitive adsorption of MB and protein.

  13. KGM-based magnetic carbon aerogels matrix for the uptake of methylene blue and methyl orange.

    PubMed

    Ye, Shuxin; Jin, Weiping; Huang, Qing; Hu, Ying; Li, Yan; Li, Bin

    2016-11-01

    In this study, the preparation of magnetic Fe and Mn oxides (Mag-FMBO) loaded carbon aerogels (CA) based on konjac glucomannan (KGM) and their performance for dyes adsorption were investigated. The prepared magnetic carbon aerogels (Mag-CA) materials were characterized by various methods, including BET surface area analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). What's more, the Mag-CA materials were used as adsorbents to remove dyes [anionic methyl orange (MO) and cationic methylene blue (MB)] from aqueous solutions. The results showed that Mag-CA had an excellent adsorption performance towards MO and MB. The adsorption equilibrium data of both MO and MB can be well described by Langmuir model. The maximum MO and MB uptake capacity of Mag-CA reached 7.42mgg(-1) and 9.37mgg(-1) according to Langmuir isotherm at 303K, respectively. Thermodynamic parameters such as ΔG, ΔH and ΔS were estimated to understand the adsorption mechanism of MO and MB. The adsorption processes of MO and MB could be well described by the pseudo-second-order model. Moreover, Mag-CA with dyes (MO or MB) were successfully regenerated by ethanol and then easily separated from aqueous solution by applying magnetic field.

  14. Reversibility of photoelectrochromism at the TiO{sub 2}/methylene blue interface

    SciTech Connect

    Tacconi, N.R. de; Carmona, J.; Rajeshwar, K.

    1997-07-01

    This paper describes the photoelectrochromic bleaching and recoloration of methylene blue in aqueous or methanolic slurry suspensions of TiO{sub 2}. Using simple modification of a UV-visible diode-array spectrometer setup, the spectral changes undergone by the dye in these solutions were monitored in situ during irradiation of the TiO{sub 2} particles and in the dark. A particular focus of this study was a systematic investigation of factors underpinning the chemical and electrochemical (kinetic) reversibility of the dye bleaching-recoloration sequence. Thus, choice of solution pH and hole capture agents is shown to be critical to the suppression of parasitic chemical and photochemical reactions involving the dye. On the other hand, dye adsorption on the TiO{sub 2} surface, the solvent medium itself, and its O{sub 2} content are all important factors in dictating the kinetic reversibility of the photoelectrochromic process. Finally, the practical implications of the findings are presented.

  15. Mechanism of Adsorptive Removal of Methylene Blue Using Dried Biomass of Rhizopus oryzae.

    PubMed

    Dey, Manash Deep; Shukla, Ruchi; Bordoloi, Naba K; Doley, Robin; Mukhopadhyay, Rupak

    2015-09-01

    Adsorption is an efficient way to remove synthetic dyes from industrial effluent. Here, we show mechanism of adsorptive removal of cationic dye methylene blue (MB) from its aqueous solution using dried biomass of Rhizopus oryzae as a biosorbent. The optimum pH and temperature for adsorption was found to be 7.0 and 28 °C, respectively. Scanning electron microscopy (SEM) of the biomass suggested distinct changes in surface topology post-MB adsorption, while Fourier transform infrared (FTIR) study indicated chemical interaction between the surface of the biomass and MB. Chemical modification of -OH and -C=O groups of biomass reduced the MB adsorption and corroborated with the FTIR analyses. Kinetics study revealed that the adsorption rate was fast initially and reached equilibrium at 4 h following a pseudo-second-order-kinetics. The adsorption isotherm followed Freundlich isotherm model with n value of 1.1615.The dried biomass of R. oryzae can be used as a potent biosorbent for the removal of MB.

  16. Fabrication of polyaniline hydrogel: Synthesis, characterization and adsorption of methylene blue

    NASA Astrophysics Data System (ADS)

    Yan, Bo; Chen, Zhonghui; Cai, Lu; Chen, Zhimin; Fu, Jianwei; Xu, Qun

    2015-11-01

    Polyaniline (PAni) hydrogel was synthesized in a facial method by using phytic acid as both dopant and cross-linking agent. Then the fabricated hydrogel was employed as an efficient adsorbent to remove the methylene blue (MB) in an aqueous solution. The as-synthesized PAni hydrogel was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The characterization results indicate that the obtained PAni hydrogel has a 3D structure, which is available for the contact between the adsorbent and dye molecules. During the adsorption, the phytic acid provides a large number of anionic phosphate groups as adsorption sites for MB molecules, which induces the high adsorption capacity up to 71.2 mg/g. The effects of pH, the PAni hydrogel mass and temperatures on adsorption efficiency were studied in details. Further experimental results indicate the adsorption kinetic fits well with the pseudo-second-order kinetic model. Compared with Freundlich model, Langmuir isotherm model was more acceptable to fit the equilibrium adsorption data. Moreover, the conceivable mechanism of the adsorption was also proposed in this work.

  17. Effects of the oxidation degree of graphene oxide on the adsorption of methylene blue.

    PubMed

    Yan, Han; Tao, Xue; Yang, Zhen; Li, Kun; Yang, Hu; Li, Aimin; Cheng, Rongshi

    2014-03-15

    In this current work, a series of graphene oxides (GO) with different oxidation degrees (OD) was prepared using Hummer method. Fundamental adsorption behavior of the GO series for removal of methylene blue (MB) from aqueous solutions has been studied. The GO series shows an overall fast and pH-independent MB adsorption, which is even capable of removing trace levels of dye completely from very dilute solutions. Furthermore, the effects of the oxidation degree (OD) on MB adsorption behavior have been investigated systematically, indicating that the dye uptakes of GO exponentially increase with the increase of OD. Further study on the adsorption mechanism shows that adsorption behavior of GO would change from a Freundlich-type to a Langmuir-type adsorption as the OD increases. It may be due to both the enhanced exfoliation degree of the carbon planes in graphite caused by oxidation and the production of more active adsorption sites. The binding features of the MB loaded GO gradually change from MB molecule parallel stacking on graphite plane through hydrophobic π-π interaction to vertical standing via electrostatic interaction with increasing OD, resulting in a significant improvement of MB uptakes. In addition, the adsorption capacity of the regenerated GO has little loss until four cycles.

  18. Surface properties and adsorption characteristics to methylene blue and iodine of adsorbents from sludge.

    PubMed

    Deng, L Y; Xu, G R; Li, G B

    2010-01-01

    Adsorbent materials created from wastewater sludge have unique surface characteristics and could be effective in adsorption applications. In this research, the sludge-adsorbents were generated by pyrolyzing mixtures of sewage sludge and H(2)SO(4). Scanning electron microscope (SEM), thermal analysis, X-ray diffraction (XRD) and X-ray photoelectron spectroscope (XPS) were used to analyze the properties of sludge-adsorbent. XPS results show that the adsorbent surface functional groups with high contents of oxygen-containing groups serve as active sites for the adsorption and affect the surface characteristics; the adsorption mechanism of methylene blue (MB) is mainly Brönsted acid-base reaction between the adsorbent surface and MB; and iodine atoms are bonded to the surface of the adsorbent mainly by dispersive interactions rather than by electrostatic interactions. The results also show that H(2)SO(4) level, pyrolysis temperature and sulfuric acid/sludge weight ratio actually affected the adsorption characteristics. Using the conditions (H(2)SO(4) level of 1-18 M, pyrolysis temperature of 650°C, and weight ratio of 0.8), the adsorption capacities for MB and iodine were 74.7-62.3 mg g(-1) and 169.5-209.3 mg g(-1), respectively.

  19. Adsorption of methylene blue on an agro-waste oiltea shell with and without fungal treatment

    NASA Astrophysics Data System (ADS)

    Liu, Jiayang; Li, Enzhong; You, Xiaojuan; Hu, Changwei; Huang, Qingguo

    2016-12-01

    A lignocellulosic waste oiltea shell (OTS) was evaluated as an inexpensive sorbent to remove methylene blue (MB) from aqueous solution. Fungal treatment of OTS increased the MB adsorption by modifying the physicochemical properties of OTS and simultaneously produced laccase as a beneficial co-product. Without fungal treatment, the maximum amount of adsorption (qm) of MB by OTS was 64.4 mg/g, whereas the treatment with fungus Pycnoporus sp. and Trametes versicolor increased qm up to 72.5 mg/g and 85.7 mg/g, respectively. This is because of the improved surface area and pore sizes as well as altered chemical compositions. The equilibrium sorption data for OTS both with and without treatment fitted to the Langmuir model, and the sorption rate data well fitted to the pseudo second-order kinetic model. The changes in free energy (ΔG°) and separation factor (RL) indicated that the sorption was spontaneous and favorable. Scanning electron microscopy and Fourier transform infrared spectroscopy showed the changes in the surface morphology and functional groups of OTS after fungal treatment. The agro-waste OTS could be utilized as a low-cost adsorbent for efficient dye removal, and fungal treatment can serve as a mild and clean technique to increase the adsorptive capacity of OTS.

  20. Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes.

    PubMed

    Szlachta, M; Wójtowicz, P

    2013-01-01

    This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m(2)/g, MWCNTs 358 m(2)/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal.

  1. Preparation of modified semi-coke by microwave heating and adsorption kinetics of methylene blue.

    PubMed

    Wang, Xin; Peng, Jin-Hui; Duan, Xin-Hui; Srinivasakannan, Chandrasekar

    2013-01-01

    Preparation of modified semi-coke has been achieved, using phosphoric acid as the modifying agent, by microwave heating from virgin semi-coke. Process optimization using a Central Composite Design (CCD) design of Response Surface Methodology (RSM) technique for the preparation of modifies semi-coke is presented in this paper. The optimum conditions for producing modified semi-coke were: concentration of phosphoric acid 2.04, heating time 20 minutes and temperature 587 degrees C, with the optimum iodine of 862 mg/g and yield of 47.48%. The textural characteristics of modified semi-coke were analyzed using scanning electron microscopy (SEM) and nitrogen adsorption isotherm. The BET surface area of modified semi-coke was estimated to be 989.60 m2/g, with the pore volume of 0.74 cm3/g and a pore diameter of 3.009 nm, with micro-pore volume contributing to 62.44%. The Methylene Blue monolayer adsorption capacity was found to be mg/g at K. The adsorption capacity of the modified semi-coke highlights its suitability for liquid phase adsorption application with a potential usage in waste water treatment.

  2. Sulfur K-edge XANES for methylene blue in photocatalytic reaction over WO3 nanomaterials

    NASA Astrophysics Data System (ADS)

    Komori, K.; Yoshida, T.; Nomoto, T.; Yamamoto, M.; Tsukada, C.; Yagi, S.; Yajima, M.; Kajita, S.; Ohno, N.

    2015-12-01

    We investigated the photocatalysis of dendritic nanostructured WO3/W composite materials fabricated by He plasma irradiation to tungsten plates, followed by the surface oxidation. The samples promoted the decolorization reaction of methylene blue (MB) aqueous solution under near infrared (NIR) light irradiation. To verify the MB molecule is actually decomposed by the photocatalysis of the samples, reaction products were analyzed by S K-edge XANES measurements for the MB solution kept with the samples under the light irradiation or in the dark. By the light irradiation, the σ*(S-C) peak in the XANES spectra reduced and a new peak originated from SO42- species was clearly observed, suggesting that S-C bonds in a MB molecule are broken by the NIR light irradiation and finally the sulfur species exists in the solution in the state of SO42- ion. After the adsorption reaction in the dark, the XANES spectra of the sample surfaces showed a sharp π*(S-C) peaks, indicating that MB molecules are adsorbed on the sample surfaces and stacked each other by the π-π interaction. These results demonstrate that the photocatalytic decomposition of MB molecules really proceeds over WO3/W composite materials even under NIR light irradiation.

  3. Adsorption of methylene blue and methyl red dyes from aqueous solutions onto modified zeolites.

    PubMed

    Ioannou, Z; Karasavvidis, Ch; Dimirkou, A; Antoniadis, V

    2013-01-01

    Zeolite, hematite, modified zeolite and commercial activated charcoal were examined for their ability to remove methylene blue (MB) and methyl red (MR) from their aqueous solutions. Modified zeolite and hematite were produced according to the Schwertmann and Cornell method while zeolite and commercial activated charcoal were obtained from S&B and Fluka AG companies, respectively. Adsorption experiments were conducted at three different adsorbent-to-solution ratios, namely 8, 16 and 24 g/L under environmental conditions and continuous stirring. Equilibrium isotherms of MB and MR were studied at different initial concentrations (from 5 × 10(-4) to 5 × 10(-3) g/L). MB adsorption kinetics were also studied. The maximum adsorption of MB and MR from their aqueous solutions was achieved at 24 g/L (adsorbent-to-dye solution ratio) after 1 h and was equal to 100% (MB) on modified zeolite and 99% (MR) on commercial activated charcoal, respectively. All the other materials achieved intermediate values of dye adsorption. From the applied kinetic models, the pseudo-second-order equation best described the adsorption of MB and MR. Consequently, modified zeolite showed the highest adsorption capacity for MB, while commercial activated charcoal showed the highest adsorption capacity of MR. The studied adsorbents can be used as filters to remove dyes from wastewaters.

  4. Experimental Design Approach for Methylene Blue Dye Removal in Aqueous Environment by Nitrilotriacetic Modified Banana Pith.

    PubMed

    Lee, Shi-Ling; Liew, Shu-Wei; Ong, Siew-Teng

    2016-01-01

    Native banana pith (NBP) was modified by using nitrilotriacetic acid to increase its efficiency and adsorption capacity for methylene blue (MB) dye. The effect of various parameters such as pH, contact time and initial dye concentration, sorption isotherm and adsorbent dosage were studied. The maximum adsorption capacity of the NBP and NTA-BP is 100 and 142.86 mg/g, respectively. The IR spectrum of NBP and NTA-BP showed the presence of both carboxyl and hydroxyl groups. From the SEM micrographs, the surface morphology of NTA-BP before adsorption appeared to be smoother as compared to that after adsorption process. The pH(pzc) of NBP is 5.6 whereas for NTA-BP is 7.6. The experimental data fitted well into Langmuir isotherm with R(2) of 0.992. Plackett-Burman design was applied to identify the significant factors in affecting the uptake whereas the interaction between the factors and their optimum levels for the maximum percentage uptake of MB were determined using response surface methodology (RSM). Based on the results, the optimum condition for adsorption of MB was by using 0.06 g of NTA-BP in dye solution at pH 6 with 120 minutes contact time. The maximum adsorption of MB by NTA-BP achieved 99.42% under the optimum condition.

  5. Removal of methylene blue from aqueous solution by wood millet carbon optimization using response surface methodology.

    PubMed

    Ghaedi, Mehrorang; Nasiri Kokhdan, Syamak

    2015-02-05

    The use of cheep, non-toxic, safe and easily available adsorbent are efficient and recommended material and alternative to the current expensive substance for pollutant removal from wastewater. The activated carbon prepared from wood waste of local tree (millet) extensively was applied for quantitative removal of methylene blue (MB), while simply. It was used to re-used after heating and washing with alkaline solution of ethanol. This new adsorbent was characterized by using BET surface area measurement, FT-IR, pH determination at zero point of charge (pHZPC) and Boehm titration method. Response surface methodology (RSM) by at least the number of experiments main and interaction of experimental conditions such as pH of solution, contact time, initial dye concentration and adsorbent dosage was optimized and set as pH 7, contact time 18 min, initial dye concentration 20 ppm and 0.2 g of adsorbent. It was found that variable such as pH and amount of adsorbent as solely or combination effects seriously affect the removal percentage. The fitting experimental data with conventional models reveal the applicability of isotherm models Langmuir model for their well presentation and description and Kinetic real rate of adsorption at most conditions efficiently can be represented pseudo-second order, and intra-particle diffusion. It novel material is good candidate for removal of huge amount of MB (20 ppm) in short time (18 min) by consumption of small amount (0.2 g).

  6. [Adsorption properties of modified graphene for methylene blue removal from wastewater].

    PubMed

    Wu, Yan; Luo, Han-Jin; Wang, Hou; Zhang, Zi-Long; Wang, Can; Wang, Yu-Wei

    2013-11-01

    In this study, cetyltrimethylammonium bromide (CTAB) was chosen to modify graphene, which was applied to remove methylene blue (MB) from aqueous solutions. The characteristics of graphene and modified graphene were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), thermal gravimetric analyzer (TGA), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The effects of factors including pH, contact time, temperature, and dosage on the adsorption properties of MB onto graphene and modified graphene were investigated. The results revealed that the addition of CTAB in preparation could obviously increase the specific surface area and improve the efficiency of removal. The adsorption processes were rapid within the first 15 min and reached equilibrium in about 120 min. The adsorption kinetics fitted well with the pseudo-second-order model. The optimal reaction temperature was 293 K, the optimal concentration of adsorbent dosage was 2 g x L(-1), and the initial pH value of the solution had little impact on the amount of adsorption. The adsorption capacity of MB on modified graphene inferred from the Langmuir model was 86.43 mg x g(-1) at 293 K, and the adsorption was an exothermic process.

  7. Green synthesis of halloysite nanotubes supported Ag nanoparticles for photocatalytic decomposition of methylene blue

    NASA Astrophysics Data System (ADS)

    Zou, MeiLing; Du, MingLiang; Zhu, Han; Xu, CongSheng; Fu, YaQin

    2012-08-01

    Using tea polyphenols (TPs) as a reductant, Ag nanoparticles (AgNPs) supported on halloysite nanotubes (HNTs) were simply and greenly synthesized for the photocatalytic decomposition of methylene blue (MB). HNTs were initially functionalized by N-β-aminoethyl-γ-aminopropyl trimethoxysilane (AEAPTMS) to introduce amino groups to form N-HNTs to fasten the AgNPs; then AgNPs were synthesized and ‘anchored’ on the surface of the HNTs. Fourier transform infrared spectroscopy was employed to testify the amino groups on the surface of the HNTs. Transmission electron microscopy, field-emission scanning electron microscopy and x-ray diffraction were utilized to characterize the structure and morphology of the synthesized HNTs supported by the AgNPs (AgNPs@N-HNTs). The results showed that the AgNPs had been synthesized and ‘anchored’ onto the surface of the HNTs with a diameter of about 20-30 nm. X-ray photoelectron spectroscopy analysis revealed the chelating interaction between the AgNPs and N atoms together with the TP molecular. The photocatalytic activity of the as-prepared AgNPs@N-HNTs catalyst was evaluated by decomposition of MB; the results showed that the prepared catalyst exhibited excellent catalytic activity and high adsorption capability to MB.

  8. Adsorption of Methylene Blue from Aqueous Solutions by Polyvinyl Alcohol/Graphene Oxide Composites.

    PubMed

    Yang, Xiaoxia; Li, Yanhui; Du, Qiuju; Wang, Xiaohui; Hu, Song; Chen, Long; Wang, Zonghua; Xia, Yanzhi; Xia, Linhua

    2016-02-01

    As a new member of the carbon family, graphene oxide (GO) has shown excellent adsorption ability to micro-pollutants in aqueous solutions. However, its tiny size makes it difficult to be removed from aqueous solutions using the conventional separation methods, which limits its practical application in the environmental protection. In this study, polyvinyl alcohol (PVA) was used as carrier immobilizing GO, and novel PVA/GO composites were prepared. The morphology and physicochemical properties of the composites were characterized by SEM, FTIR and TGA analysis. The adsorption properties of methylene blue (MB) onto the composites were studied through investigating the experimental parameters such as solution pH, adsorbent dosage, contact time and temperature. The isotherm data were analyzed using the Langmuir, Freundlich and Dubinin-Radushkevich models. The calculated maximum adsorption capacity reached 476.2 mg/g at 50% GO content. The pseudo-first-order kinetic, pseudo-second-order kinetic and intra-particle diffusion models were used to explore the adsorption kinetics. The results showed that the dynamic data were fitted to the pseudo-second-order kinetic model.

  9. Methylene Blue Modulates β-Secretase, Reverses Cerebral Amyloidosis, and Improves Cognition in Transgenic Mice*

    PubMed Central

    Mori, Takashi; Koyama, Naoki; Segawa, Tatsuya; Maeda, Masahiro; Maruyama, Nobuhiro; Kinoshita, Noriaki; Hou, Huayan; Tan, Jun; Town, Terrence

    2014-01-01

    Amyloid precursor protein (APP) proteolysis is required for production of amyloid-β (Aβ) peptides that comprise β-amyloid plaques in the brains of patients with Alzheimer disease (AD). Here, we tested whether the experimental agent methylene blue (MB), used for treatment of methemoglobinemia, might improve AD-like pathology and behavioral deficits. We orally administered MB to the aged transgenic PSAPP mouse model of cerebral amyloidosis and evaluated cognitive function and cerebral amyloid pathology. Beginning at 15 months of age, animals were gavaged with MB (3 mg/kg) or vehicle once daily for 3 months. MB treatment significantly prevented transgene-associated behavioral impairment, including hyperactivity, decreased object recognition, and defective spatial working and reference memory, but it did not alter nontransgenic mouse behavior. Moreover, brain parenchymal and cerebral vascular β-amyloid deposits as well as levels of various Aβ species, including oligomers, were mitigated in MB-treated PSAPP mice. These effects occurred with inhibition of amyloidogenic APP proteolysis. Specifically, β-carboxyl-terminal APP fragment and β-site APP cleaving enzyme 1 protein expression and activity were attenuated. Additionally, treatment of Chinese hamster ovary cells overexpressing human wild-type APP with MB significantly decreased Aβ production and amyloidogenic APP proteolysis. These results underscore the potential for oral MB treatment against AD-related cerebral amyloidosis by modulating the amyloidogenic pathway. PMID:25157105

  10. Binding, aggregation and photochemical properties of methylene blue in mitochondrial suspensions.

    PubMed

    Gabrielli, Dino; Belisle, Eduardo; Severino, Divinomar; Kowaltowski, Alicia J; Baptista, Mauricio S

    2004-03-01

    Methylene Blue (MB) has well-established photochemical properties and has been used in a variety of photochemical applications including photodynamic therapy. Despite the fact that most of MB's cytotoxic effects in cells are attributed to mitochondrial damage, the interactions of this dye with mitochondria and the consequent effects on photochemical properties have not yet been fully determined. We monitored MB binding, aggregation and its ability to release singlet oxygen (1O2) on irradiation when interacting with mitochondrial suspensions. MB actively binds to mitochondria and enters the matrix in a manner stimulated by the mitochondrial proton potential and by the increase in mitochondrial concentrations. The greater accumulation of MB in mitochondria with elevated proton potentials or those treated with high concentrations of MB results in the formation of MB dimers, previously shown to be less effective generators of 1O2. Accumulation of MB within mitochondria with high membrane potentials also results in the reduction of MB to the photochemically inactive leuco-MB. Indeed, irradiation of mitochondria with high proton potentials in the presence of MB results in the generation of approximately half the quantity of 1O2 compared with 1O2 generated in mitochondria with low proton potentials. These differences in photochemical properties should influence the cytotoxic effects of photodynamic treatment in the presence of MB.

  11. Extraction and recovery of methylene blue from industrial wastewater using benzoic acid as an extractant.

    PubMed

    Muthuraman, G; Teng, Tjoon Tow; Leh, Cheu Peng; Norli, I

    2009-04-15

    Liquid-liquid extraction (LLE) of methylene blue (MB) from industrial wastewater using benzoic acid (extractant) in xylene has been studied at 27 degrees C. The extraction of the dye increased with increasing extractant concentration. The extraction abilities have been studied on benzoic acid concentration in the range of 0.36-5.8x10(-2) M. The distribution ratio of the dye is reasonably high (D=49.5) even in the presence of inorganic salts. Irrespective of the concentration of dye, extraction under optimal conditions was 90-99% after 15 min of phase separation. The extracted dye in the organic phase can be back extracted into sulphuric acid solution. The resultant recovered organic phase can be reused in succeeding extraction of dye with the yield ranging from 99 to 87% after 15 times reused, depending on the concentration of the initial feed solution. Experimental parameters examined were benzoic acid concentration, effect of diluent, effect of pH, effect of initial dye concentration, effect of equilibration time, various stripping agents, aqueous to organic phase ratio in extraction, organic to aqueous phase ratio in stripping and reusability of solvent.

  12. A high sensitivity field effect transistor biosensor for methylene blue detection utilize graphene oxide nanoribbon.

    PubMed

    Lin, Ting-Chun; Li, Yan-Sheng; Chiang, Wei-Hung; Pei, Zingway

    2017-03-15

    In this work, we developed a field effect transistor (FET) biosensor utilizing solution-processed graphene oxide nanoribbon (GONR) for methylene blue (MB) sensing. MB is a unique material; one of its crucial applications is as a marker in the detection of biomaterials. Therefore, a highly sensitive biosensor with a low detection limit that can be fabricated simply in a noncomplex detection scheme is desirable. GONR is made by unzipping multiwall carbon nanotubes, which can be mass-produced at low temperature. The GONR-FET biosensor demonstrated a sensitivity of 12.5μA/mM (determined according to the drain current difference caused by the MB concentration change). The Raman spectra indicate that the materials quality of the GONR and the domain size for the C=C sp(2) bonding were both improved after MB detection. X-ray photoelectron spectroscopy revealed that the hydroxyl groups on the GONR were removed by the reductive MB. According to XPS and Raman, the positive charge is proposed to transfer from MB to GONR during sensing. This transfer causes charge in-neutrality in the GONR which is compensated by releasing •OH functional groups. With high sensitivity, a low detection limit, and a simple device structure, the GONR-FET sensor is suitable for sensing biomaterials.

  13. Methylene blue photodynamic therapy in rats' wound healing: 21 days follow-up

    NASA Astrophysics Data System (ADS)

    Carneiro, Vanda Sanderana Macêdo; Catao, Maria Helena Chaves de Vasconcelos; Menezes, Rebeca Ferraz; Araújo, Natália Costa; Gerbi, Marleny Elizabeth Martinez

    2015-06-01

    The experimental evaluated the photodynamic therapy (PDT) in wound healing. It used 60 male rats, making two circular wounds at each animal. They were treated at 48hs intervals, with methylene blue (MB), low level laser treatment (LLLT) or both, thus resulting in PDT. The wounds were observed 01, 03, 07, 14 and 21 days after and then processed and subjected to HE staining to analyze granulation tissue, necrosis, epithelialization and collagen. After day 1, wounds treated with MB showed necrosis less intense than other groups, and the PDT group showed more intense granulation tissue. At day 3, reepithelialization was absent for half of injuries in the PDT group, and this group was also with lower collagen. However, at day 7, this same group presented reepithelialization more advanced than control group, which did not happen with those treated with MB or LLLT (p = 0.015). The results allow us to conclude that PDT difficulted reepithelization at 7th day and interfered in standard healing. However, when used separately, MB and LLLT interfered significantly compared to the control group, which did not happened to the PDT group. There was no significant difference between the treatment groups in other analysed times.

  14. Control of burn wound sepsis in rats by methylene blue-mediated photodynamic treatment

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroyuki; Sato, Shunichi; Kawauchi, Satoko; Saitoh, Daizoh; Shinomiya, Nariyoshi; Ashida, Hiroshi; Terakawa, Mitsuhiro

    2012-02-01

    Control of wound sepsis is an important challenge in traumatology. However, increase in the drug-resistant bacteria makes this challenge considerably difficult in recent years. In this study, we attempted to control burn wound sepsis in rats by photodynamic treatment, which has been reported to be effective against some drug-resistant bacteria. A 20% TBSA (total body surface area) full-thickness burn was made in rat dorsal skin, and five days after injury, a suspension of P. aeruginosa was applied to the wound surface. At 30 min after infection, a methylene blue (MB) solution was applied to the wound surface; 5 min afterwards, the wound was illuminated with a 665-nm light emitting diode (LED) array for 10 min. This treatment (application of MB and illumination) was repeated 3 times successively. The averaged light intensity on the wound surface was 3.3 mW/cm2, the corresponding total light dose being 5.9 J/cm2. One week after injury, the numbers of bacteria in the blood and liver were counted by colony forming assay. In the liver, the number of bacteria of the treated group was significantly lower than that of the sham control group without photodynamic treatment. In the blood, no bacteria were detected in the treated group, while a certain amount of bacteria was detected in the control group. These results demonstrate the efficacy of MB-mediated PDT with a red LED array to control burn wound sepsis.

  15. Preparation and characterization of methylene blue nanoparticles for Alzheimer's disease and other tauopathies.

    PubMed

    Jinwal, Umesh K; Groshev, Anastasia; Zhang, Juan; Grover, Aditya; Sutariya, Vijaykumar B

    2014-01-01

    Methylene blue (MB) has been shown to slow down the progression of the Alzheimer's disease (AD) and other tauopathies; however distribution of MB into the brain is limited due its high hydrophilicity. In this study, we aimed to prepare novel hydrophobic glutathione coated PLGA nanoparticles to improve bioavailability of MB in the brain. Glutathione coated poly-(lactide-co-glycolide) (PLGA-b-PEG) nanoparticles (NPs) were prepared and tested in two different cell culture models of AD expressing microtubule associated protein tau (tau). The NPs showed a particle size averaging 136.5±4.4nm, which is suitable for the blood brain barrier (BBB) permeation. The in vitro release profile of the NPs exhibited no initial burst release and showed sustained drug release for up to 144 hours. Interestingly, treatment of newly formulated MB-NPs showed a potent reduction in both endogenous and over expressed tau protein levels in human neuroblastoma SHSY-5Y cells expressing endogenous tau and transfected HeLa cells over-expressing tau protein, respectively. Furthermore, in vitro BBB Transwell™ study showed significantly higher permeation of MB-NP compared to the MB solution through the co culture of rat brain endothelial 4 (RBE4) and C6 astrocytoma cells (p<0.05). The proposed MB loaded nanoparticles could provide a more effective treatment option for AD and many other related disorders.

  16. Designing metallic iron based water filters: Light from methylene blue discoloration.

    PubMed

    Btatkeu-K, B D; Tchatchueng, J B; Noubactep, C; Caré, S

    2016-01-15

    Available water filtration systems containing metallic iron (Fe(0) filters) are pragmatically designed. There is a lack of sound design criteria to exploit the full potential of Fe(0) filters. A science-based design relies on valuable information on processes within a Fe(0) filter, including chemical reactions, hydrodynamics and their relation to the performance of the filter. The aim of this study was to establish a simple method to evaluate the initial performance of Fe(0) filters. The differential adsorptive affinity of methylene blue (MB) onto sand and iron oxide is exploited to characterize the evolution of a Fe(0)/sand system using the pure sand system as operational reference. Five systems were investigated for more than 70 days: pure sand, pure Fe(0), Fe(0)/sand, Fe(0)/pumice and Fe(0)/sand/pumice. Individual systems were characterized by the extent of changes in pH value, iron breakthrough, MB breakthrough and hydraulic conductivity. Results showed that for MB discoloration (i) pure sand was the most efficient system, (ii) hybrid systems were more sustainable than the pure Fe(0) system, and (iii) the pores of used pumice are poorly interconnected. Characterizing the initial reactivity of Fe(0) filters using MB discoloration has introduced a powerful tool for the exploration of various aspects of filter design.

  17. Removal of methylene blue from aqueous solution by a solvothermal-synthesized graphene/magnetite composite.

    PubMed

    Ai, Lunhong; Zhang, Chunying; Chen, Zhonglan

    2011-09-15

    In this study, we have demonstrated a facile one-step solvothermal method for the synthesis of the graphene nanosheet (GNS)/magnetite (Fe(3)O(4)) composite. During the solvothermal treatment, in situ conversion of FeCl(3) to Fe(3)O(4) and simultaneous reduction of graphene oxide (GO) into graphene in ethylene glycol solution were achieved. Electron microscopy study suggests the Fe(3)O(4) spheres with a size of about 200 nm are uniformly distributed and firmly anchored on the wrinkled graphene layers with a high density. The resulting GNS/Fe(3)O(4) composite shows extraordinary adsorption capacity and fast adsorption rates for removal of organic dye, methylene blue (MB), in water. The adsorption kinetics, isotherms and thermodynamics were investigated in detail to reveal that the kinetics and equilibrium adsorptions are well-described by pseudo-second-order kinetic and Langmuir isotherm model, respectively. The thermodynamic parameters reveal that the adsorption process is spontaneous and endothermic in nature. This study shows that the as-prepared GNS/Fe(3)O(4) composite could be utilized as an efficient, magnetically separable adsorbent for the environmental cleanup.

  18. Methylene Blue Doped Films of Wool Keratin with Antimicrobial Photodynamic Activity.

    PubMed

    Aluigi, Annalisa; Sotgiu, Giovanna; Torreggiani, Armida; Guerrini, Andrea; Orlandi, Viviana T; Corticelli, Franco; Varchi, Greta

    2015-08-12

    In this work, keratin films doped with different amounts of methylene blue (MB) were developed in order to prepare new biodegradable and biocompatible materials for tissue engineering and wound healing, able to exert antimicrobial photodynamic activity upon irradiation with visible light. Preliminary results indicated that the swelling ratio, as well as the MB release, increases by increasing the pH. Moreover, the generation of reactive oxygen species (ROS) and singlet oxygen can be easily triggered and controlled by a fine-tuning of the irradiation time and MB concentration in the films. As concerns the photodynamic effects on keratin, the ROS attack does not induce any significant photodegradation on the protein, even if a slight photo-oxidation of sulfonated amino acids occurs. Finally, the film with the highest MB concentration (400 μg per gram of keratin) displays a significant photobactericidal activity against Staphylococcus aureus with a bacterial reduction that increases by increasing the irradiation time. In particular, the irradiation of KFMB400 film incubated with S. aureus at a concentration of 10(8) cfu mL(-1) determined the 99.9% killing rate and the killing effect increased proportionally with irradiation time.

  19. Cellular and Molecular Actions of Methylene Blue in the Nervous System

    PubMed Central

    Oz, Murat; Lorke, Dietrich E.; Hasan, Mohammed; Petroianu, George A.

    2010-01-01

    Methylene Blue (MB), following its introduction to biology in the 19th century by Ehrlich, has found uses in various areas of medicine and biology. At present, MB is the first line of treatment in methemoglobinemias, is used frequently in the treatment of ifosfamide-induced encephalopathy, and is routinely employed as a diagnostic tool in surgical procedures. Furthermore, recent studies suggest that MB has beneficial effects in Alzheimer's disease and memory improvement. Although the modulation of the cGMP pathway is considered the most significant effect of MB, mediating its pharmacological actions, recent studies indicate that it has multiple cellular and molecular targets. In the majority of cases, biological effects and clinical applications of MB are dictated by its unique physicochemical properties including its planar structure, redox chemistry, ionic charges, and light spectrum characteristics. In this review article, these physicochemical features and the actions of MB on multiple cellular and molecular targets are discussed with regard to their relevance to the nervous system. PMID:19760660

  20. Synthetically engineered chitosan-based materials and their sorption properties with methylene blue in aqueous solution.

    PubMed

    Guo, Rui; Wilson, Lee D

    2012-12-15

    Chitosan (CS) and poly(acrylic acid) (PAA) were crosslinked by an ionic gelation method to form super absorbent polymers (SAPs). CS and PAA form amide bonds between the amino and carboxyl groups. The CS-PAA copolymers were synthetically engineered by varying the feed ratios of the prepolymer units. The copolymer materials possess tunable sorption and mucoadhesive properties with a backbone structure resembling proteinaceous materials. The sorption properties of the copolymers toward methylene blue (MB) in aqueous solution were studied using UV-Vis spectrophotometry at ambient pH and 295 K. The copolymers showed markedly varied interactions with MB, from physisorption- to chemisorption-like behavior, in accordance with their composition, surface area, and pore structure characteristics. The sorption isotherms were evaluated with the Sips model to provide estimates of the sorption properties. The sorbent surface area (271 and 943 m(2)/g) and the sorption capacity (Q(m)=1.03 and 3.59 mmol/g) were estimated for the CS-PAA copolymer/MB systems in aqueous solution.

  1. Twenty years of vasoplegic syndrome treatment in heart surgery. Methylene blue revised

    PubMed Central

    Evora, Paulo Roberto Barbosa; Alves, Lafaiete; Ferreira, Cesar Augusto; Menardi, Antônio Carlos; Bassetto, Solange; Rodrigues, Alfredo José; Scorzoni, Adilson; Vicente, Walter Vilella de Andrade

    2015-01-01

    Objective This study was conducted to reassess the concepts established over the past 20 years, in particular in the last 5 years, about the use of methylene blue in the treatment of vasoplegic syndrome in cardiac surgery. Methods A wide literature review was carried out using the data extracted from: MEDLINE, SCOPUS and ISI WEB OF SCIENCE. Results The reassessed and reaffirmed concepts were 1) MB is safe in the recommended doses (the lethal dose is 40 mg/kg); 2) MB does not cause endothelial dysfunction; 3) The MB effect appears in cases of NO up-regulation; 4) MB is not a vasoconstrictor, by blocking the cGMP pathway it releases the cAMP pathway, facilitating the norepinephrine vasoconstrictor effect; 5) The most used dosage is 2 mg/kg as IV bolus, followed by the same continuous infusion because plasma concentrations sharply decrease in the first 40 minutes; and 6) There is a possible "window of opportunity" for MB's effectiveness. In the last five years, major challenges were: 1) Observations about side effects; 2) The need for prophylactic and therapeutic guidelines, and; 3) The need for the establishment of the MB therapeutic window in humans. Conclusion MB action to treat vasoplegic syndrome is time-dependent. Therefore, the great challenge is the need, for the establishment the MB therapeutic window in humans. This would be the first step towards a systematic guideline to be followed by possible multicenter studies. PMID:25859872

  2. Photodynamic effects of methylene blue-loaded polymeric nanoparticles on dental plaque bacteria

    PubMed Central

    Klepac-Ceraj, Vanja; Patel, Niraj; Song, Xiaoqing; Holewa, Colleen; Patel, Chitrang; Kent, Ralph; Amiji, Mansoor M.; Soukos, Nikolaos S.

    2011-01-01

    Background and Objectives Photodynamic therapy (PDT) is increasingly being explored for treatment of oral infections. Here, we investigate the effect of PDT on human dental plaque bacteria in vitro using methylene blue (MB)-loaded poly(lactic-co-glycolic) (PLGA) nanoparticles with a positive or negative charge and red light at 665 nm. Study Design/Materials and Methods Subgingival plaque samples were obtained from 14 patients with chronic periodontitis. Suspensions of plaque microorganisms from seven patients were sensitized with anionic, cationic PLGA nanoparticles (50 μg/ml equivalent to MB) or free MB (50 μg/ml) for 20 min followed by exposure to red light for 5 min with a power density of 100 mW/cm2. Polymicrobial oral biofilms, which were developed on blood agar in 96-well plates from dental plaque inocula obtained from seven patients, were also exposed to PDT as above. Following the treatment, survival fractions were calculated by counting the number of colony-forming units. Results The cationic MB-loaded nanoparticles exhibited greater bacterial phototoxicity in both planktonic and biofilm phase compared to anionic MB-loaded nanoparticles and free MB, but results were not significantly different (p>0.05). Conclusion Cationic MB-loaded PLGA nanoparticles have the potential to be used as carriers of MB for PDT systems. PMID:22057487

  3. Comparative evaluation of methylene blue and demeclocycline for enhancing optical contrast of gliomas in optical images

    NASA Astrophysics Data System (ADS)

    Wirth, Dennis; Snuderl, Matija; Curry, William; Yaroslavsky, Anna

    2014-09-01

    Contrast agents have shown to be useful in the detection of cancers. The goal of this study was to compare enhancement of brain cancer contrast using reflectance and fluorescence confocal imaging of two fluorophores, methylene blue (MB) and demeclocycline (DMN). MB absorbs light in the red spectral range and fluoresces in the near-infrared. It is safe for in vivo staining of human skin and breast tissue. However, its safety for staining human brain is questionable. Thus, DMN, which absorbs light in the violet spectral range and fluoresces between 470 and 570 nm, could provide a safer alternative to MB. Fresh human gliomas, obtained from surgeries, were cut in half and stained with aqueous solutions of MB and DMN, respectively. Stained tissues were imaged using multimodal confocal microscopy. Resulting reflectance and fluorescence optical images were compared with hematoxylin and eosin histopathology, processed from each imaged tissue. Results indicate that images of tissues stained with either stain exhibit comparable contrast and resolution of morphological detail. Further studies are required to establish the safety and efficacy of these contrast agents for use in human brain.

  4. Biogenic gold nanoparticles enhance methylene blue-induced phototoxic effect on Staphylococcus epidermidis

    NASA Astrophysics Data System (ADS)

    Maliszewska, Irena; Leśniewska, Agata; Olesiak-Bańska, Joanna; Matczyszyn, Katarzyna; Samoć, Marek

    2014-06-01

    There is considerable current interest in photodynamic inactivation (PDI) as potential antimicrobial therapy. This study reports successful implementation of PDI of Staphylococcus epidermidis using methylene blue (MB) in combination with biogenic gold nanoparticles (GNP). Monodispersed colloidal GNP were synthesized by reduction of Au+3 in the presence of cell-free filtrate of Trichoderma koningii and were characterized by a number of techniques including UV-Vis and fluorescence spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) to be 12 ± 3 nm spherical gold particles coated with proteins. Studies on the role of the cell-free filtrate proteins in the synthesis of the GNP indicate that the process is nonenzymatic but involves interactions of various amino acids with gold ions. A Xe lamp (550-780 nm) or a He-Ne laser (632 nm) was used as light sources to study the effect of MB alone, the GNP alone, and the MB-GNP mixture on the viability of bacterial cells. Lethal photosensitization of S. epidermidis with the MB-GNP mixture was achieved after 5 and 10 min exposure to laser or Xe lamp, respectively. It has been found that the MB-GNP mixture exhibits a significant antibacterial activity already in the absence of any light source and gives an enhanced antimicrobial response when using either a laser or a Xe lamp source for photosensitization.

  5. Highly effective removal of Methylene Blue using functionalized attapulgite via hydrothermal process.

    PubMed

    Zhang, Zhifang; Wang, Wenbo; Wang, Aiqin

    2015-07-01

    Attapulgite (APT) has been frequently used for the adsorptive removal of dyes from aqueous solution owing to its unique one-dimensional nanoscale structure and low-cost, abundant, eco-friendly advantages. In this work, APT was functionalized under mild hydrothermal condition using chloroacetic acid (CA) with COOH functional groups to improve its adsorption properties. The effect of hydrothermal modification on the microstructure and physicochemical features of APT was investigated by Fourier transform infrared spectroscopy, X-ray diffraction and Field-emission scanning electron microscopy analyses. The effects of hydrothermal reaction parameters on the adsorption properties of modified APT were intensively investigated. It was revealed that the rearrangement of crystal structure and the surface functionalization of APT with COOH groups cause the surprising increase of adsorption capability for Methylene Blue (MB). The removal ratio of raw APT for MB is only 59.52%, while modified APT could almost completely remove MB in the 200 mg/L of MB solution with a removal ratio of 99.8%. The adsorption kinetics fitted pseudo second-order kinetic model, and the adsorption isotherm could be described with Langmuir isotherm model very well. The hydrogen-bonding interaction, electrostatic attraction and chemical association are the main driving force for the adsorption process.

  6. Immobilization of methylene blue onto bentonite and its application in the extraction of mercury (II).

    PubMed

    Hassanien, Mohamed M; Abou-El-Sherbini, Khaled S; Al-Muaikel, Nayef S

    2010-06-15

    Methylene blue was immobilized onto bentonite (BNT). The modified clay (MB-BNT) was used to extract Hg(2+) at pH 6.0 yielding Hg-MB-BNT. BNT, MB-BNT and Hg-MB-BNT were characterized by X-ray diffractometry, infrared spectra, and elemental and thermogravimetric analyses. MB is suggested to be intercalated into the major phase of BNT; montmorillonite mineral (MMT), lying parallel to the aluminosilicate layers, with a capacity of 36 mequiv./100g. MB-BNT shows good stability in 0.1-1M hydrochloric or nitric acids, ammonium hydroxide, and concentrated Na(+), K(+) or NH(4)(+) chlorides or iodides. It shows good selectivity towards Hg(2+) with an extraction capacity of 37 mequiv./100g in the presence of I(-) giving rise to a ratio of MB/Hg(2+)/I(-) 1:1:3 in the clay phase. Extracted Hg(2+) could be quantitatively recovered by ammonia buffer at pH 8.5. MB-BNT was successfully applied to recover Hg(2+) from spiked natural water and cinnabar mineral samples using the optimum conditions; pH 6.0, time of stirring 10 min and 10 mL of 0.05 M NH(4)Cl/NH(4)OH at pH 8.5 as eluent.

  7. Biosorption of methylene blue from aqueous solution by rice husk in a fixed-bed column.

    PubMed

    Han, Runping; Wang, Yuanfeng; Yu, Weihong; Zou, Weihua; Shi, Jie; Liu, Hongmin

    2007-03-22

    In this study, the ability of rice husk to adsorb methylene blue (MB) from aqueous solution was investigated in a fixed-bed column. The effects of important parameters, such as the value of initial pH, existed salt, the flow rate, the influent concentration of MB and bed depth, were studied. The Thomas model was applied to adsorption of MB at different flow rate, influent concentration and bed depth to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design using non-linear regression. The bed-depth/service time analysis (BDST) model was also applied at different bed depth to predict the breakthrough curves. The two models were found suitable for describing the biosorption process of the dynamic behavior of the rice husk column. All the results suggested that rice husk as adsorbent to removal MB from solution be efficient, and the rate of biosorption process be rapid. When the flow rate was 8.2ml min(-1) and the influent concentration of MB was 50mgl(-1), the equilibrium adsorption biomass reached 4.41mgg(-1) according to Thomas model.

  8. Adsorption studies of methylene blue and phenol onto black stone cherries prepared by chemical activation.

    PubMed

    Rodríguez Arana, José María Ramos; Mazzoco, René Reyes

    2010-08-15

    The production of granular activated carbon (GAC) basically depends on the correct selection of carbonization temperature, activation ratio and agent (physical or chemical) as well as the raw material. Black cherry, available in Mexico with relative abundance, is of the same genus as the European cherry, whose stones have yielded good GAC production results. Black cherry stones were tried as raw material for GAC production with phosphoric acid as the activating agent. Optimum carbonization temperatures were found to be between 500 and 550 degrees C with an activation ratio of 1.0 g of phosphoric acid/g raw material. Under these conditions the maximum yield was 48.16 g of GAC/100 g black cherry stones. The experimental adsorption parameters fitted into Langmuir's model with a maximum adsorption of 321.75 mg of methylene blue/g GAC and 133.33 mg of phenol/g GAC. Black cherry shells are an abundant agricultural by-product with no uses, and therefore are an alternative for producing GAC.

  9. Removal of methylene blue from aqueous solution by Artist's Bracket fungi: kinetic and equilibrium studies.

    PubMed

    Naghipour, Daryush; Taghavi, Kamran; Moslemzadeh, Mehrdad

    2016-01-01

    In this study, adsorption of methylene blue (MB) dye onto Artist's Bracket (AB) fungi was investigated in aqueous solution. Fourier transform infrared and scanning electron microscopy were used to investigate surface characteristic of AB fungi. Influence of operational parameters such as pH, contact time, biosorbent dosage, dye concentration, inorganic salts and temperature was studied on dye removal efficiency. With the increase of pH from 3 to 9, removal efficiency increased from 74.0% to 90.4%. Also, it reduced from 99.8% to 81.8% with increasing initial MB concentration from 25 mg L(-1) to 100 mg L(-1), whereas it increased from 54.7% to 98.7% and from 98.5% to 99.9% with increasing biosorbent dosage from 0.5 g L(-1) to 2 g L(-1) and with increasing temperature from 25 °C to 50 °C, respectively. Isotherm studies have shown adsorption of MB dye over the AB fungi had a better coefficient of determination (R(2)) of 0.98 for Langmuir isotherm. In addition, the maximum monolayer adsorption capacity (qm) was 100 mg g(-1). Also, the MB dye adsorption process followed pseudo-second-order kinetic. In general, AB fungi particles can be favorable for removal of MB dye from dye aqueous solution with natural pH and high temperature.

  10. A sensitive resveratrol assay with a simple probe methylene blue by resonance light scattering technique

    NASA Astrophysics Data System (ADS)

    Xiang, Haiyan; Dai, Kaijin; Luo, Qizhi; Duan, Wenjun; Xie, Yang

    2011-01-01

    A novel resonance light scattering (RLS) method was developed for the determination of resveratrol based on the interaction between resveratrol and methylene blue (MB). It was found that at pH 8.69, the weak RLS intensity of MB was remarkably enhanced by the addition of trace amount of resveratrol with the maximum peak located at 385.0 nm. Under the optimum conditions, a good linear relationship between the enhanced RLS intensities and the concentrations of resveratrol was obtained over the range of 2.0-14.0 μg ml -1 with the detection limit (3 σ) of 0.63 μg ml -1. The results of the analysis of resveratrol in synthetic samples and human urine are satisfactory, which showed it may provide a more sensitive, convenient, rapid and reproducible method for the detection of resveratrol, especially in biological and pharmaceutical field. In this work, the characteristics of RLS, absorption and fluorescence spectra of the resveratrol-MB system, the influencing factors and the optimum conditions of the reaction were investigated.

  11. Kinetics of basic dye (methylene blue) biosorption by giant duckweed (Spirodela polyrrhiza).

    PubMed

    Waranusantigul, P; Pokethitiyook, P; Kruatrachue, M; Upatham, E S

    2003-01-01

    Wastewater containing pigments and/or dyes can cause serious water pollution problems in the form of reduced light penetration and photosynthesis, and the toxicity from heavy metals associated with pigments and/or dyes. Laboratory investigations, of the potential use of dried Spirodela polyrrhiza biomass as an adsorbent for the removal of the basic dye methylene blue from aqueous solution were conducted. A series of experiments were undertaken in an agitated batch adsorber to assess the effect of the system variables, i.e. sorbent dosage, pH, and contact time. The results showed that as the amount of the dried S. polyrrhiza increased, the percentage of dye sorption increased accordingly. At pH 2.0 the sorption of dye was not favorable, while the sorption at other pHs (3.0-11.0) was remarkable. There was no significant difference in the dye concentration remaining when the pH was increased from 3.0 to 11.0. The dye removal time was influenced by the initial dye concentration, and the process followed the first-order rate kinetics. The rate constants for intraparticle diffusion were 1.00 and 3.27 mg/g/min1/2 for 300 and 500 mg/l of dye, respectively.

  12. Photophysical and antibacterial properties of complex systems based on smectite, a cationic surfactant and methylene blue.

    PubMed

    Donauerová, Alena; Bujdák, Juraj; Smolinská, Miroslava; Bujdáková, Helena

    2015-10-01

    Solid or colloidal materials with embedded photosensitizers are promising agents from the medical or environmental perspective, where the direct use of photoactive solutions appears to be problematic. Colloids based on layered silicates of the saponite (Sap) and montmorillonite (Mon) type, including those modified with dodecylammonium cations (C12) and photosensitizer--methylene blue (MB) were studied. Two representatives of bacteria, namely Enterobacter cloacae and Escherichia coli, were selected for this work. A spectral study showed that MB solutions and also colloids with Sap including C12 exhibited the highest photoactivities. The antimicrobial properties of the smectite colloids were not directly linked to the photoactivity of the adsorbed MB cations. They were also influenced by other parameters, such as light vs. dark conditions, the spectrum, power and duration of the light used for the irradiation; growth phases, and the pre-treatment of microorganisms. Both the photoactivity and antimicrobial properties of the colloids were improved upon pre-modification with C12. Significantly higher antimicrobial properties were observed for the colloids based on Mon with MB in the form of molecular aggregates without significant photoactivities. The MB/Mon colloids, both modified and non-modified with C12 cations, exhibited higher antimicrobial effects than pure MB solution. Besides the direct effect of photosensitization, the surface properties of the silicate particles likely played a crucial role in the interactions with microorganisms.

  13. Real-Time Near-Infrared Fluorescence-Guided Identification of the Ureters using Methylene Blue

    PubMed Central

    Matsui, Aya; Tanaka, Eiichi; Choi, Hak Soo; Kianzad, Vida; Gioux, Sylvain; Lomnes, Stephen J.; Frangioni, John V.

    2009-01-01

    Background The aim of this study was to determine whether the invisible near-infrared (NIR) fluorescence properties of methylene blue (MB), a dye already FDA-approved for other indications, could be exploited for real-time, intraoperative identification of the ureters. Methods The optical properties of MB were quantified in vitro. Open surgery and laparoscopic NIR fluorescence imaging systems were employed. Yorkshire pigs were injected intravenously with: 0.1 mg/kg MB (n = 8), 10 mg furosemide followed by 0.1 mg/kg MB (n = 6), or 0.5 mg/kg MB (n = 6). The contrast-to-background ratio (CBR) of the kidney and ureters, and MB concentration in urine, were quantified. Results Peak MB absorbance, emission, and intensity in urine occurred at 668 nm, 688 nm, and 20 μM, respectively. After intravenous injection, doses as low as 0.1 mg/kg MB provided prolonged imaging of the ureters, and a dose of 0.5 mg/kg provided statistically significant improvement of CBR. Pre-injection of furosemide increased urine volume but did not improve CBR. Laparoscopic identification of the ureter using MB NIR fluorescence was demonstrated. Conclusions Ureteral imaging using MB NIR fluorescence provides sensitive, real-time, intraoperative identification of the ureters during open and laparoscopic surgeries. PMID:20117811

  14. Investigation on physical properties of L-alanine: An effect of Methylene blue dye

    NASA Astrophysics Data System (ADS)

    Shkir, Mohd.; Yahia, I. S.; Al-Qahtani, A. M. A.; Ganesh, V.; AlFaify, S.

    2017-03-01

    In the present investigation, a bulk size (35 mm × 25 mm × 15 mm) single crystal of 0.1 wt% Methylene blue dye (MLB) added L-alanine is grown at room temperature using solution technique for the first time. The L-alanine crystals with higher concentrations of dye (0.5 and 1 wt%) were also grown. Solubility study was performed at different temperatures. Structural, vibrational and good quality was inveterate by powder XRD, FT-Raman and SEM analyses. High transmittance in dyed crystals was confirmed. The presence of MLB dye was confirmed by an absorption band centered at 650 nm. Optical band gap was calculated for pure and dyed L-alanine crystals and found to be 5.45 and 4.49 eV respectively. Photoluminescence intensity of UV-A emission band centered at 332 nm was found to be enhanced due to the presence of dye. The dielectric measurement was done in the wide frequency range. Furthermore, the third order nonlinear optical parameters are enhanced in dyed L-alanine crystals determined by Z-scan technique.

  15. Effects of methylene blue in acute lung injury induced by oleic acid in rats

    PubMed Central

    Cassiano Silveira, Ana Paula; Vento, Daniella Alves; Albuquerque, Agnes Afrodite Sumarelli; Celotto, Andrea Carla; Tefé-Silva, Cristiane; Ramos, Simone Gusmão; Rubens de Nadai, Tales; Rodrigues, Alfredo José; Poli-Neto, Omero Benedicto

    2016-01-01

    Background In acute lung injury (ALI), rupture of the alveolar-capillary barrier determines the protein-rich fluid influx into alveolar spaces. Previous studies have reported that methylene blue (MB) attenuates such injuries. This investigation was carried out to study the MB effects in pulmonary capillary permeability. Methods Wistar rats were divided into five groups: (I) Sham: saline bolus; (II) MB, MB infusion for 2 h; (III) oleic acid (OA), OA bolus; (IV) MB/OA, MB infusion for 2 h, and at 5 min after from the beginning, concurrently with an OA bolus; and (V) OA/MB, OA bolus, and after 2 h, MB infusion for 2 h. After 4 h, blood, bronchoalveolar lavage (BAL), and lung tissue were collected from all groups for analysis of plasma and tissue nitric oxide, calculation of the wet weight to dry weight ratio (WW/DW), and histological examination of lung tissue. Statistical analysis was performed using nonparametric test. Results Although favourable trends have been observed for permeability improvement parameters (WW/WD and protein), the results were not statistically significant. However, histological analysis of lung tissue showed reduced lesion areas in both pre- and post-treatment groups. Conclusions The data collected using this experimental model was favourable only through macroscopic and histological analysis. These observations are valid for both MB infusions before or after induction of ALI. PMID:26855944

  16. Methylene blue attenuates acute liver injury induced by paraquat in rats.

    PubMed

    Chen, Jun-Liang; Dai, Li; Zhang, Peng; Chen, Wei; Cai, Gao-Shan; Qi, Xiao-Wei; Hu, Ming-Zhu; Du, Bin; Pang, Qing-Feng

    2015-09-01

    Paraquat (PQ) poisoning often leads to severe oxidative liver injury. Recent studies have reported that methylene blue (MB) can prevent oxidative stress-induced diseases. This study tested the hypothesis that MB treatment reduced acute liver injury induced by PQ in rats. Adult male Sprague-Dawley (SD) rats were randomly divided into four groups: (1) normal group, (2) MB group (2mg/kg i.p.), (3) PQ group (35 mg/kg i.p.) and (4) PQ+MB group (MB 2mg/kg i.p. administrated 2h after PQ). We evaluated the changes of liver histopathology, serum liver enzymatic activities, oxidative stress, heme oxygenase-1 expression, and mitochondrial permeability transition. The rats were injected with PQ produced liver injury, evidenced by histological changes and elevated serum alkaline phosphatase and alanine transaminase levels; PQ also led to oxidative stress, an increase of malondialdehyde content and mitochondrial permeability transition pore opening. Pathological damage and all of the above mentioned markers were reversed in the animals treated with MB than in those who received PQ alone. Meanwhile, MB significantly increased the contents of superoxide dismutase, adenosine triphosphate and the expression of heme oxygenase-1. In conclusion, MB had a protective effect against PQ-induced hepatic damage in rats. The mechanisms of the protection seem to be the inhibition of mitochondrial permeability transition opening and the increase of heme oxygenase-1 expression.

  17. Rejected tea as a potential low-cost adsorbent for the removal of methylene blue.

    PubMed

    Nasuha, N; Hameed, B H; Din, Azam T Mohd

    2010-03-15

    The adsorption of methylene blue (MB) from aqueous solution using a low-cost adsorbent, rejected tea (RT), has been studied by batch adsorption technique. The adsorption experiments were carried out under different conditions of initial concentration (50-500 mg/L), solution pH 3-12, RT dose (0.05-1g) and temperature (30-50 degrees C). The equilibrium data were fitted to Langmuir and Freundlich isotherms and the equilibrium adsorption was best described by the Langmuir isotherm model with maximum monolayer adsorption capacities found to be 147, 154 and 156 mg/g at 30, 40 and 50 degrees C, respectively. Three kinetic models, pseudo-first-order, pseudo-second-order and intraparticle diffusion were employed to describe the adsorption mechanism. The experimental results showed that the pseudo-second-order equation is the best model that describes the adsorption behavior with the coefficient of correlation R(2)>or=0.99. The results suggested that RT has high potential to be used as effective adsorbent for MB removal.

  18. Adsorption of methylene blue on low-cost adsorbents: a review.

    PubMed

    Rafatullah, Mohd; Sulaiman, Othman; Hashim, Rokiah; Ahmad, Anees

    2010-05-15

    In this article, the use of low-cost adsorbents for the removal of methylene blue (MB) from solution has been reviewed. Adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those which are not easily biodegradable. The removal of MB, as a pollutant, from waste waters of textile, paper, printing and other industries has been addressed by the researchers. Currently, a combination of biological treatment and adsorption on activated carbon is becoming more common for removal of dyes from wastewater. Although commercial activated carbon is a preferred adsorbent for color removal, its widespread use is restricted due to its relatively high cost which led to the researches on alternative non-conventional and low-cost adsorbents. The purpose of this review article is to organize the scattered available information on various aspects on a wide range of potentially low-cost adsorbents for MB removal. These include agricultural wastes, industrial solid wastes, biomass, clays minerals and zeolites. Agricultural waste materials being highly efficient, low cost and renewable source of biomass can be exploited for MB remediation. It is evident from a literature survey of about 185 recently published papers that low-cost adsorbents have demonstrated outstanding removal capabilities for MB.

  19. Removal of methylene blue from aqueous solution by fibrous clay minerals.

    PubMed

    Hajjaji, M; Alami, A; El Bouadili, A

    2006-07-31

    Kinetics and equilibrium processes of the methylene blue (MB) retention from aqueous solution by a mixture of fibrous clay minerals, which was isolated from a naturally occurring clay, were investigated. For these purposes, the effects of contact time, initial adsorbate concentration, adsorbent content, pH and ionic strength were determined. The results show that the MB retention obeys a pseudo-first order equation and the process is a diffusion controlled solid-state reaction. Moreover, the isotherm data fitted the Langmuir equation and the MB binding process became more energetic with the increase of the adsorbent concentration. In addition, the augmentation of the clay content or the initial MB concentration reduced the adsorption capacity, presumably because of the clay particles microaggregation and/or the occurrence of MB deriving species. On the other hand, it is observed that the MB uptake limit is reduced in low acid pH, particularly below the PZC, as well as in ionic strengthen solutions. These facts are linked to the silanol group protonation and to the reduction of the electrostatic forces induced by the clay particles, respectively.

  20. Modeling the mechanism involved during the sorption of methylene blue onto fly ash.

    PubMed

    Kumar, K Vasanth; Ramamurthi, V; Sivanesan, S

    2005-04-01

    Batch sorption experiments were carried out to remove methylene blue from its aqueous solutions using fly ash as an adsorbent. Operating variables studied were initial dye concentration, fly ash mass, pH, and contact time. Maximum color removal was observed at a basic pH of 8. Equilibrium data were represented well by a Langmuir isotherm equation with a monolayer sorption capacity of 5.718 mg/g. Sorption data were fitted to both Lagergren first-order and pseudo-second-order kinetic models and the data were found to follow pseudo-second-order kinetics. Rate constants at different initial concentrations were estimated. The process mechanism was found to be complex, consisting of both surface adsorption and pore diffusion. The effective diffusion parameter D(i) values were estimated at different initial concentrations and the average value was determined to be 2.063 x 10(-9)cm2/s. Analysis of sorption data using a Boyd plot confirms the particle diffusion as the rate-limiting step for the dye concentration ranges studied in the present investigation (20 to 60 mg/L).

  1. Spectroscopic Study of CpG Alternating DNA-Methylene Blue Interaction for Methylation Detection.

    PubMed

    Hosseini, Morteza; Khaki, Fereshteh; Dadmehr, Mehdi; Ganjali, Mohammad Reza

    2016-05-01

    Recognition of methylated DNA sites would be useful strategy due to the important roles of methylation in disease occurrence and developmental processes. The interaction of CpG rich methylated and unmethylated DNA hybrid with methylene blue (MB) as an optical probe has been investigated by absorption, emission, circular dichorism and fluorescence anisotropy analysis. Titration of MB with both sequences caused a hypsochromism and decreased the absorption of MB that indicating an intercalative mode of interaction. The experimental results revealed that MB as the optical indicator could distinguish between the methylated and unmethylated DNA sequences. Under optimum conditions, upon the addition of methylated dsDNA, the fluorescence intensity increased in linear range from 1.0 × 10(-9) to 1.0 × 10(-6) M with detection limit of 7.2 × 10(-10) M and on the other hand, the intensity of MB showed no change with addition of unmethylated dsDNA.

  2. Removal of methylene blue dye from water by a spent bleaching earth biosorbent.

    PubMed

    Belhaine, Ali; Ghezzar, Mouffok Redouane; Abdelmalek, Fatiha; Tayebi, Kamel; Ghomari, Abdelhamid; Addou, Ahmed

    2016-12-01

    This work is about the valorization of spent bleaching earth (SBE) at low cost from the AFIA oil refinery in Algeria's western region. The biowaste has been burned to eliminate the oil traces, then it has been valorized in two ways: (i) chemically, using phosphoric acid to obtain SBEC and (ii) thermally at 750 °C to create SBEH. The obtained materials were used for the first time as biosorbents in the wastewater treatment field. The three biomaterials show very interesting adsorption properties, with specific surfaces of 194.2, 784.6 and 888.5 m(2) g(-1) for SBE, SBEC and SBEH, respectively. The analysis has revealed that the obtained materials are alumino-silicates. The three biowastes have been used to remove methylene blue dye from water. The dye was totally eliminated by a physisorption mechanism in the presence of 1 g L(-1) of each biowaste after 8, 10, 20 min of contact time. The highest correlation coefficient (R(2) = 0.99) was related to the Langmuir isotherm, indicating a good fit with this model, and explaining the biosorption as a monolayer process. According to this model, the adsorption capacities were 123.3, 185.2 and 188.7 mg g(-1) for SBE, SBEH and SBEC, respectively. This study shows that SBE can be used as an alternative to commercial adsorbents for dye removal from water.

  3. Facile fabrication of magnetic carboxymethyl starch/poly(vinyl alcohol) composite gel for methylene blue removal.

    PubMed

    Gong, Guisheng; Zhang, Faai; Cheng, Zehong; Zhou, Li

    2015-11-01

    This study presents a simple method to fabricate magnetic carboxymethyl starch/poly(vinyl alcohol) (mCMS/PVA) composite gel. The obtained mCMS/PVA was characterized by Fourier transform infrared (FTIR) spectra, vibrating-sample magnetometer (VSM) and scanning electron microscopy (SEM) measurements. The application of mCMS/PVA as an adsorbent for removal of cationic methylene blue (MB) dye from water was investigated. Benefiting from the combined merits of carboxymethyl starch and magnetic gel, the mCMS/PVA simultaneously exhibited excellent adsorption property toward MB and convenient magnetic separation capability. The effects of initial dye concentration, contact time, pH and ionic strength on the adsorption performance of mCMS/PVA adsorbent were investigated systematically. The adsorption process of mCMS/PVA for MB fitted pseudo-second-order model and Freundlich isotherm. Moreover, desorption experiments revealed that the mCMS/PVA adsorbent could be well regenerated in ethanol solution without obvious compromise of removal efficiency even after eight cycles of desorption/adsorption. Considering the facile fabrication process and robust adsorption performance, the mCMS/PVA composite gel has great potential as a low cost adsorbent for environmental decontamination.

  4. Activated carbon coated palygorskite as adsorbent by activation and its adsorption for methylene blue.

    PubMed

    Zhang, Xianlong; Cheng, Liping; Wu, Xueping; Tang, Yingzhao; Wu, Yucheng

    2015-07-01

    An activation process for developing the surface and porous structure of palygorskite/carbon (PG/C) nanocomposite using ZnCl2 as activating agent was investigated. The obtained activated PG/C was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (SEM), and Brunauer-Emmett-Teller analysis (BET) techniques. The effects of activation conditions were examined, including activation temperature and impregnation ratio. With increased temperature and impregnation ratio, the collapse of the palygorskite crystal structure was found to accelerate and the carbon coated on the surface underwent further carbonization. XRD and SEM data confirmed that the palygorskite structure was destroyed and the carbon structure was developed during activation. The presence of the characteristic absorption peaks of CC and C-H vibrations in the FTIR spectra suggested the occurrence of aromatization. The BET surface area improved by more than 11-fold (1201 m2/g for activated PG/C vs. 106 m2/g for PG/C) after activation, and the material appeared to be mainly microporous. The maximum adsorption capacity of methylene blue onto the activated PG/C reached 351 mg/g. The activated PG/C demonstrated better compressive strength than activated carbon without palygorskite clay.

  5. Sorption of methylene blue on treated agricultural adsorbents: equilibrium and kinetic studies

    NASA Astrophysics Data System (ADS)

    Tiwari, D. P.; Singh, S. K.; Sharma, Neetu

    2015-03-01

    Agricultural adsorbents are reported to have a remarkable performance for adsorption of dyes. In the present study, formaldehyde and sulphuric acid treated two agricultural adsorbents; potato peel and neem bark are used to adsorb methylene blue. On the whole, the acid-treated adsorbents are investigated to have high sorption efficiency compared to HCHO treated adsorbents. The percentage removal efficiency of H2SO4 treated potato peel (APP) increases considerably high from 75 to 100 % with increase in adsorbent dose, whereas the removal efficiency of H2SO4 treated neem bark (ANB) is found to be 98 % after adding the first dose only. The monolayer sorption behaviour of HCHO treated potato peel (PP) and APP is well defined by Langmuir, whereas the chemisorptions behaviour of HCHO treated neem bark (NB) and ANB is suggested by Temkin's isotherm model. The maximum adsorption capacity measured is highest in ANB followed by NB, PP and APP with the values of 1000, 90, 47.62 and 40.0 mg/g, respectively. The pseudo-second-order kinetic model fitted well with the observed data of all the four adsorbents. The results obtained reveal that NB and ANB both are good adsorbents compared to PP and APP.

  6. Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars.

    PubMed

    Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong

    2016-01-01

    Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB.

  7. Bacteria encapsulated electrospun nanofibrous webs for remediation of methylene blue dye in water.

    PubMed

    Sarioglu, Omer Faruk; Keskin, Nalan Oya San; Celebioglu, Asli; Tekinay, Turgay; Uyar, Tamer

    2017-04-01

    In this study, preparation and application of novel biocomposite materials that were produced by encapsulation of bacterial cells within electrospun nanofibrous webs are described. A commercial strain of Pseudomonas aeruginosa which has methylene blue (MB) dye remediation capability was selected for encapsulation, and polyvinyl alcohol (PVA) and polyethylene oxide (PEO) were selected as the polymer matrices for the electrospinning of bacteria encapsulated nanofibrous webs. Encapsulation of bacterial cells was monitored by scanning electron microscopy (SEM) and fluorescence microscopy, and the viability of encapsulated bacteria was checked by live/dead staining and viable cell counting assay. Both bacteria/PVA and bacteria/PEO webs have shown a great potential for remediation of MB, yet bacteria/PEO web has shown higher removal performances than bacteria/PVA web, which was probably due to the differences in the initial viable bacterial cells for those two samples. The bacteria encapsulated electrospun nanofibrous webs were stored at 4°C for three months and they were found as potentially storable for keeping encapsulated bacterial cells alive. Overall, the results suggest that electrospun nanofibrous webs are suitable platforms for preservation of living bacterial cells and they can be used directly as a starting inoculum for bioremediation of water systems.

  8. Removal of Congo Red and Methylene Blue from Aqueous Solutions by Vermicompost-Derived Biochars

    PubMed Central

    Yang, Gang; Wu, Lin; Xian, Qiming; Shen, Fei; Wu, Jun; Zhang, Yanzong

    2016-01-01

    Biochars, produced by pyrolyzing vermicompost at 300, 500, and 700°C were characterized and their ability to adsorb the dyes Congo red (CR) and Methylene blue (MB) in an aqueous solution was investigated. The physical and chemical properties of biochars varied significantly based on the pyrolysis temperatures. Analysis of the data revealed that the aromaticity, polarity, specific surface area, pH, and ash content of the biochars increased gradually with the increase in pyrolysis temperature, while the cation exchange capacity, and carbon, hydrogen, nitrogen and oxygen contents decreased. The adsorption kinetics of CR and MB were described by pseudo-second-order kinetic models. Both of Langmuir and Temkin model could be employed to describe the adsorption behaviors of CR and MB by these biochars. The biochars generated at higher pyrolysis temperature displayed higher CR adsorption capacities and lower MB adsorption capacities than those compared with the biochars generated at lower pyrolysis temperatures. The biochar generated at the higher pyrolytic temperature displayed the higher ability to adsorb CR owing to its promoted aromaticity, and the cation exchange is the key factor that positively affects adsorption of MB. PMID:27144922

  9. New Twist on an Old Favorite: Gentian Violet and Methylene Blue Antibacterial Foams

    PubMed Central

    Edwards, Karen

    2016-01-01

    Significance: Absorptive antibacterial dressings that assist in controlling bioburden without risks of cytotoxicity or residual absorption can be effectively used for prolonged periods throughout the wound healing continuum. Recent Advances: Until recently, gentian violet and methylene blue (GV/MB) antibacterial dressings have been commercially available only in polyvinyl alcohol (PVA) foam; polyurethane (PU) foam bonded with GV and MB with thin film backing is now commercially available. GV/MB PU foam does not require hydration or a necessary secondary dressing. GV/MB PVA and PU foam dressings were recently granted FDA clearance as antibacterial dressings, as opposed to bacteriostatic dressings as previously classified. Within the class of antibacterial dressings, GV/MB foam dressings are of lower cost alternative to silver- or iodine-based antibacterial dressings with no risk of absorption of any of the foam components into the tissues. Critical Issues: Control of wound bioburden levels by antibacterial agents and absorption of excess exudate are crucial in preventing infections that drastically increase the price of wound care. Use of GV/MB dressings may improve wound healing outcomes and decrease overall costs through super absorption, promotion of autolytic debridement, bioburden reduction, ease of use, and decreased dressing change frequency. Future Directions: Evolution in resistant bacterial strains will drive continual changes in advanced wound care products. Demand will increase for economically priced, versatile wound care dressings that assist in debridement, maintain a moist wound environment, absorb and trap bacterial debris, and decrease dressing change frequency. PMID:26858911

  10. Removal of methylene blue from aqueous solution by wood millet carbon optimization using response surface methodology

    NASA Astrophysics Data System (ADS)

    Ghaedi, Mehrorang; Kokhdan, Syamak Nasiri

    2015-02-01

    The use of cheep, non-toxic, safe and easily available adsorbent are efficient and recommended material and alternative to the current expensive substance for pollutant removal from wastewater. The activated carbon prepared from wood waste of local tree (millet) extensively was applied for quantitative removal of methylene blue (MB), while simply. It was used to re-used after heating and washing with alkaline solution of ethanol. This new adsorbent was characterized by using BET surface area measurement, FT-IR, pH determination at zero point of charge (pHZPC) and Boehm titration method. Response surface methodology (RSM) by at least the number of experiments main and interaction of experimental conditions such as pH of solution, contact time, initial dye concentration and adsorbent dosage was optimized and set as pH 7, contact time 18 min, initial dye concentration 20 ppm and 0.2 g of adsorbent. It was found that variable such as pH and amount of adsorbent as solely or combination effects seriously affect the removal percentage. The fitting experimental data with conventional models reveal the applicability of isotherm models Langmuir model for their well presentation and description and Kinetic real rate of adsorption at most conditions efficiently can be represented pseudo-second order, and intra-particle diffusion. It novel material is good candidate for removal of huge amount of MB (20 ppm) in short time (18 min) by consumption of small amount (0.2 g).

  11. Eradication of bacteria in suspension and biofilms using methylene blue-loaded dynamic nanoplatforms.

    PubMed

    Wu, Jianfeng; Xu, Hao; Tang, Wei; Kopelman, Raoul; Philbert, Martin A; Xi, Chuanwu

    2009-07-01

    The bacterial killing efficiency of a dynamic nanoplatform (DNP) was evaluated. The polyacrylamide (PAA) hydrogel matrix of the DNP was loaded with methylene blue (MB) and was previously applied successfully to killing rat C6 glioma tumor cells in culture. This series of experiments is aimed at determining the suitability of this nanoplatform for elimination of bacterial infections. Suspended cultures of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter sp. were exposed to activated ( approximately 650-nm laser light) MB-PAA-DNPs. The killing efficiency of nanoparticle mass concentration, light irradiance and fluence, and dark incubation time was determined on each of the bacterial species. Moreover, the ability of activated MB-PAA-DNPs to inhibit biofilm growth and eradicate and disperse preformed biofilms, preformed on glass and polystyrene surfaces, was demonstrated. The data revealed that activated MB-PAA-DNPs eradicated all species of bacteria examined. Also, encapsulation of MB into the PAA-DNP matrix significantly diminished the observed dark toxicity of free dye. The photobactericidal efficacy of MB-PAA-DNP was found to be higher for gram-positive bacteria than for gram-negative bacteria. In addition, activated MB-PAA-DNP can inhibit biofilm growth and eradicate almost all of the early-age biofilms that are formed by all of the bacteria examined.

  12. Methylene blue covalently loaded polyacrylamide nanoparticles for enhanced tumor-targeted photodynamic therapy†

    PubMed Central

    Qin, Ming; Hah, Hoe Jin; Kim, Gwangseong; Nie, Guochao; Lee, Yong-Eun Koo

    2013-01-01

    The use of targeted nanoparticles (NPs) as a platform for loading photosensitizers enables selective accumulation of the photosensitizers in the tumor area, while maintaining their photodynamic therapy (PDT) effectiveness. Here two novel kinds of methylene blue (MB)-conjugated polyacrylamide (PAA) nanoparticles, MBI-PAA NPs and MBII-PAA NPs, based on two separate MB derivatives, are developed for PDT. This covalent conjugation with the NPs (i) improves the loading of MB, (ii) prevents any leaching of MB from the NPs and (iii) protects the MB from the effects of enzymes in the biological environment. The loading of MB into these two kinds of NPs was controlled by the input amount, resulting in concentrations with optimal singlet oxygen production. For each of the MB-NPs, the highest singlet oxygen production was found for an MB loading of around 11 nmol mg−1. After attachment of F3 peptide groups, for targeting, each of these NPs was taken up, selectively, by MDA-MB-435 tumor cells, in vitro. PDT tests demonstrated that both kinds of targeted NPs resulted in effective tumor cell kill, following illumination, while not causing dark toxicity. PMID:21479315

  13. Methylene blue improves brain oxidative metabolism and memory retention in rats.

    PubMed

    Callaway, Narriman Lee; Riha, Penny D; Bruchey, Aleksandra K; Munshi, Zeenat; Gonzalez-Lima, F

    2004-01-01

    Methylene blue (MB) increases mitochondrial oxygen consumption and restores memory retention in rats metabolically impaired by inhibition of cytochrome c oxidase. This study tested two related hypotheses using biochemical and behavioral techniques: (1) that low-level MB would enhance brain cytochrome c oxidation, as tested in vitro in brain homogenates and after in vivo administration to rats and (2) that corresponding low-dose MB would enhance spatial memory retention in normal rats, as tested 24 h after rats were trained in a baited holeboard maze for 5 days with daily MB posttraining injections. The biochemical in vitro studies showed an increased rate of brain cytochrome c oxidation with the low but not the high MB concentrations tested. The in vivo administration studies showed that the corresponding MB low dose (1 mg/kg) increased brain cytochrome c oxidation 24 h after intraperitoneal injection, but not after 1 or 2 h postinjection. In the behavioral studies, spatial memory retention in probe trials (percentage of visits to training-baited holes compared to total visits) was significantly better for MB-treated than saline control groups (66% vs. 31%). Together the findings suggest that low-dose MB enhances spatial memory retention in normal rats by increasing brain cytochrome c oxidase activity.

  14. Biodegradation of redox dye Methylene Blue by up-flow anaerobic sludge blanket reactor.

    PubMed

    Ong, Soon-An; Toorisaka, Eiichi; Hirata, Makoto; Hano, Tadashi

    2005-09-30

    The objective of this study is to evaluate the decolorization of Methylene Blue (MB) by an up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated under batch condition with total treatment volume of 3l and operation time of 24 h per batch. It was found that the color of MB disappeared within a few minutes after entering into the UASB reactor due to reduction by anaerobic biomass. However, the reduced MB was re-oxidized again by air after discharged from the reactor and thus caused low color removal efficiency. The presence of suitable amount of organic content (sucrose and peptone) as an electron donor played an important factor for color removal. It was observed that more than 90% of color removal efficiency was achieved in the UASB reactor with 0.627 mmoll(-1) of MB concentration and the presence of low amount of organic content (<0.45 g COD/(ld)). Biological dye reduction kinetics depends on the concentration of dye and reducing equivalents. The kinetic behavior of MB biodegradation by microbes was also investigated to determine the model involved in the process.

  15. High adsorption capacity of V-doped TiO2 for decolorization of methylene blue

    NASA Astrophysics Data System (ADS)

    Nguyen, Thanh-Binh; Hwang, Moon-Jin; Ryu, Kwang-Sun

    2012-07-01

    In this study, pure TiO2 (V-TiO2-0) and V-doped TiO2 (V-TiO2-x, x = 1-10 mol%) were synthesized using a new sol-gel method. The adsorption capacity of the V-TiO2-x samples was evaluated by measuring the removal of methylene blue (MB) from aqueous solution via decolorization. Since the adsorption capacity was affected by the specific surface area, the interaction between adsorbate (MB) and adsorbent (V-TiO2-x), and the structure of the adsorbent, the physicochemical properties of the samples were investigated. Among the V-doped TiO2-x samples, the V-TiO2-10 sample showed the highest adsorption capacity, which was 11.36 times greater than that of pure TiO2, removing 85.2% of the MB after 2 h. Moreover, changing the molar ratio of the reactants in the V-TiO2-10 sample improved the performance of the material so that 91.6% of the MB was removed after 2 h.

  16. Facile decolorization of methylene blue with flower-like manganese wads.

    PubMed

    Yang, Aili; Huang, Chinpao; Wei, Bingqing; Zhang, Zhengjun

    2014-01-01

    Flower-like manganese wads (MWs) were synthesized via a simple and inexpensive ultrasonic irradiation method for the first time. MWs were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and transmission electronic microscopy. The decolorization efficiency of MWs for methylene blue (MB) azo dye was examined as a function of pH, stirring time, MW dosage and initial concentration of the MB solution. Results show that MWs have excellent decolorization performance for MB with a higher efficiency (and without using H2O2 or other devises such as UV light and ultrasonic irradiation) compared to other catalysts, such as the mixture of Mn3O4 and H2O2 (with a maximum decolorization rate of 99.7% in 3 h), ZnS and CdS under light irradiation (with a maximum decolorization rate of 73% in 6 h), and sulfate modified titania under solar radiation (with a maximum decolorization rate of nearly 100% in 4 h).

  17. Adsorption of methylene blue on an agro-waste oiltea shell with and without fungal treatment

    PubMed Central

    Liu, Jiayang; Li, Enzhong; You, Xiaojuan; Hu, Changwei; Huang, Qingguo

    2016-01-01

    A lignocellulosic waste oiltea shell (OTS) was evaluated as an inexpensive sorbent to remove methylene blue (MB) from aqueous solution. Fungal treatment of OTS increased the MB adsorption by modifying the physicochemical properties of OTS and simultaneously produced laccase as a beneficial co-product. Without fungal treatment, the maximum amount of adsorption (qm) of MB by OTS was 64.4 mg/g, whereas the treatment with fungus Pycnoporus sp. and Trametes versicolor increased qm up to 72.5 mg/g and 85.7 mg/g, respectively. This is because of the improved surface area and pore sizes as well as altered chemical compositions. The equilibrium sorption data for OTS both with and without treatment fitted to the Langmuir model, and the sorption rate data well fitted to the pseudo second-order kinetic model. The changes in free energy (ΔG°) and separation factor (RL) indicated that the sorption was spontaneous and favorable. Scanning electron microscopy and Fourier transform infrared spectroscopy showed the changes in the surface morphology and functional groups of OTS after fungal treatment. The agro-waste OTS could be utilized as a low-cost adsorbent for efficient dye removal, and fungal treatment can serve as a mild and clean technique to increase the adsorptive capacity of OTS. PMID:27917929

  18. Electrocoagulation of methylene blue and eosin yellowish using mild steel electrodes.

    PubMed

    Golder, A K; Hridaya, N; Samanta, A N; Ray, S

    2005-12-09

    The paper presents the study of electrocoagulation (EC) of aqueous dye solutions of two different industrial dyes in a batch stirred cell. Experiments were carried out with 200 mg/l individual concentration of methylene blue (MB) and eosin yellowish (EY) in presence of NaCl as electrolyte. Effect of operating time and current density on the decolorization of dye solutions, reduction of chemical oxygen demand (COD) and variation in conductivity, pH during treatment has been studied. Small difference between color diminution and COD reduction has been found with the progress of treatment. First-order rate equation for dye removal has been developed from the experimental results. Sludge formation during EC and problems associated with this solid waste generation and disposal has been assessed. Energy consumption in KWh/m(3) with reduction of COD (kg) during treatment has been reported. Electric power consumption of 1.5 KWh reduces 0.21 and 0.11 kg COD from 0.24 and 0.14 kg of initial COD for MB and EY, respectively, starting from 200 mg/l dye concentration.

  19. Microstructure and photocatalytic activity of natural rutile from China for oxidation of methylene blue in water

    NASA Astrophysics Data System (ADS)

    Chuan, X.-Y.; Lu, A. H.; Chen, J.; Li, N.; Guo, Y. J.

    2008-05-01

    Natural rutile from China was found to have good photocatalytic activity for methylene blue (MB). Under UV irradiation, 50% of MB was decomposed in three hours by natural rutile, 90% in 77 hours and 100% in 119 hours. The Brunauer-Emmett-Teller (BET) specific surface area of natural rutile was only 0.4495 m2/g. In order to explain the decomposition of MB, rutile was characterized by XRD, FESEM and TEM, revealing a modulated structure. Crystal structural parameters are consistent with the data from JCPDS. Chemical composition approximates to Ti1.019O2. Photocatalytic properties of rutile are believed to relate to metal ionic substitution, vacancies and defects in its microstructure. Natural rutile is a practical photocatalyst, although its reaction rate is a fifth of anatase. Rutile might be effective and practical for a large-scale photocatalytic decomposition of organic pollutants in quiet and still waters (e.g. pools and lakes) since it is relatively cheap and widely available.

  20. Methylene blue biosorption by pericarp of corn, alfalfa, and agave bagasse wastes.

    PubMed

    Rosas-Castor, José M; Garza-González, María T; García-Reyes, Refugio B; Soto-Regalado, Eduardo; Cerino-Córdova, Felipe J; García-González, Alcione; Loredo-Medrano, José A

    2014-01-01

    The presence of dyes in effluent is a matter of concern due to their toxicologic and aesthetical effects. In this research, locally available agro-industrial wastes (Zea mays pericarp, ZMP; Agave tequilana bagasse, ATB; and Medicago sativa waste, MSW) were used as alternative low-cost adsorbents for the removal of methylene blue (MB) from aqueous solutions. The adsorbents were characterized physically and chemically by Fourier transform infrared, scanning electron microscopy, potentiometric titrations, and N2 physisorption. MB adsorption experiments were carried out in batch systems and experimental data were used to calculate the adsorption isotherm model parameters (Langmuir, Freundlich, and Temkin) and the adsorption kinetic model parameters (pseudo-first- and pseudo-second-order models). MB-loaded biosorbents were desorbed with deionized water, ethanol (10% and 50% v/v), hydrochloric acid (0.01 and 0.05 N), and sodium hydroxide (0.1 N) at room temperature, and the best eluent was used in various adsorption-desorption cycles. The selected agricultural wastes can be considered as promising adsorbents for dye uptake from water since they exhibit considerable MB adsorption capacity (MSW 202.6 mg g(-1), ATB 156.2mg g(-1), and ZMP 110.9mg g(-1)), but it is lower than that reported for activated carbon; however, the biosorbents show higher adsorption rate than powdered activated carbon. Furthermore, the adsorbents can be economically regenerated with HCl solutions and reused for seven adsorption-desorption cycles.

  1. Guava (Psidium guajava) leaf powder: novel adsorbent for removal of methylene blue from aqueous solutions.

    PubMed

    Ponnusami, V; Vikram, S; Srivastava, S N

    2008-03-21

    Batch sorption experiments were carried out using a novel adsorbent, guava leaf powder (GLP), for the removal of methylene blue (MB) from aqueous solutions. Potential of GLP for adsorption of MB from aqueous solution was found to be excellent. Effects of process parameters pH, adsorbent dosage, concentration, particle size and temperature were studied. Temperature-concentration interaction effect on dye uptake was studied and a quadratic model was proposed to predict dye uptake in terms of concentration, time and temperature. The model conforms closely to the experimental data. The model was used to find optimum temperature and concentration that result in maximum dye uptake. Langmuir model represent the experimental data well. Maximum dye uptake was found to be 295mg/g, indicating that GLP can be used as an excellent low-cost adsorbent. Pseudo-first-order, pseudo-second order and intraparticle diffusion models were tested. From experimental data it was found that adsorption of MB onto GLP follow pseudo second order kinetics. External diffusion and intraparticle diffusion play roles in adsorption process. Free energy of adsorption (DeltaG degrees ), enthalpy change (DeltaH degrees ) and entropy change (DeltaS degrees ) were calculated to predict the nature of adsorption. Adsorption in packed bed was also evaluated.

  2. Comparative study of polymer containing beta-cyclodextrin and -COOH for adsorption toward aniline, 1-naphthylamine and methylene blue.

    PubMed

    Zhao, Dong; Zhao, Liang; Zhu, Cheng-Shen; Shen, Xiangyu; Zhang, Xiaozhuan; Sha, Baofeng

    2009-11-15

    Three different polymers P1, P2 and P3 (P1 containing both beta-CD and -COOH, P2 containing beta-CD and P3 containing -COOH) were synthesized and applied to adsorption toward aniline, 1-naphthylamine and methylene blue. The concentrations (C) before and after adsorption were determined and the adsorption capacities (q) of P1, P2 and P3 were calculated. The maximum adsorption capacities (q(max)) toward aniline: q(max) (P1)=104 micromol g(-1), q(max) (P2)=14.9 micromol g(-1) and q(max) (P3)=53.1 micromol g(-1); toward 1-naphthylamine: q(max) (P1)=184 micromol g(-1), q(max) (P2)=53.8 micromol g(-1) and q(max) (P3)=125 micromol g(-1); toward methylene blue: q(max) (P1)=200 micromol g(-1), q(max) (P2)=12.7 micromol g(-1) and q(max) (P3)=215 micromol g(-1). P1 exhibited remarkable adsorption toward all the three adsorbates. P2 was almost equal to P1 in adsorption toward methylene blue, but was less efficient than P1 in adsorption toward aniline and 1-naphthylamine. P3 also exhibited considerable adsorption toward aniline and 1-naphthylamine, but was inefficient toward methylene blue. P1 was obtained from nontoxic materials and through environment friendly procedures, so it was potentially an efficient and green adsorbent for water purification.

  3. Removal of basic (Methylene Blue) and acid (Egacid Orange) dyes from waters by sorption on chemically treated wood shavings.

    PubMed

    Janos, Pavel; Coskun, Sezen; Pilarová, Vera; Rejnek, Jaroslav

    2009-02-01

    Spruce wood shavings from Picea abies were used for an adsorptive removal of both basic as well as acid dyes from waters. The sorption properties of the sorbents were modified with HCl, Na(2)CO(3) and Na(2)HPO(4). The treatment of the wood sorbents with alkaline carbonate solution as well as with phosphate solution increased the sorption ability for the basic dye (Methylene Blue), whereas the treatment with mineral acid decreased the sorption ability for Methylene Blue to some extent. The opposite is true for the sorption of the acid dye--Egacid Orange. The maximum sorption capacities estimated from the Langmuir-Freundlich isotherms ranged from 0.060 to 0.165 mmol g(-1) for Methylene Blue, and from 0.045 to 0.513 mmol g(-1) for Egacid Orange. The basic dye sorption decreased at low pH values in accordance with a presupposed ion-exchange mechanism of the sorption. The sorption of acid dye, on the other hand, decreased with increasing pH. The presence of inorganic salts as well as surfactants exhibited only minor effects on the dye sorption.

  4. Water-insoluble sericin/β-cyclodextrin/PVA composite electrospun nanofibers as effective adsorbents towards methylene blue.

    PubMed

    Zhao, Rui; Wang, Yong; Li, Xiang; Sun, Bolun; Jiang, Ziqiao; Wang, Ce

    2015-12-01

    A novel water-insoluble sericin/β-cyclodextrin/poly (vinyl alcohol) composite nanofiber adsorbent was prepared by electrospinning and followed by thermal crosslinking for removal of cationic dye methylene blue from aqueous solution. Fourier transform infrared spectroscopy and solubility experiments confirmed that sericin and β-cyclodextrin were incorporated into the nanofibers and the crosslinking reaction occurred successfully. Kinetics, isotherms and thermodynamics analysis were studied for adsorption of methylene blue. The adsorption process is better fitted with the pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacities are 187.97, 229.89, and 261.10mg/g at the temperatures 293, 313 and 333 K, respectively. Thermodynamic parameters showed that methylene blue adsorption was endothermic and spontaneous. In addition, the fiber membrane adsorbent could be easily separated from dye solution and showed high recyclable removal efficiency. All these results suggest that crosslinked sericin/β-cyclodextrin/poly(vinyl alcohol) composite nanofibers could be potential recyclable adsorbents in dye wastewater treatment.

  5. Fully-automated radiosynthesis and in vitro uptake investigation of [N-methyl-¹¹C]methylene blue.

    PubMed

    Schweiger, Lutz F; Smith, Tim A D

    2013-10-01

    Malignant melanoma is a type of skin cancer which can spread rapidly if not detected early and left untreated. Positron Emission Tomography (PET) is a powerful imaging technique for detecting cancer but with only a limited number of radiotracers available the development of novel PET probes for detection and prevention of cancer is imperative. In the present study we present the fully-automated radiosynthesis of [N-methyl-(11)C]methylene blue and an in vitro uptake study in metastasic melanoma cell lines. Using the GE TRACERlab FXc Pro module [N-methyl-(11)C]methylene blue was isolated via solid-phase extraction in an average time of 36 min after end of bombardment and formulated with a radiochemical purity greater than 95%. The in vitro uptake study of [N-methyl-(11)C]methylene blue in SK-MEL28 melanin-expressing melanoma cell line demonstrated in site-specific binding of 51% promoting it as a promising melanoma PET imaging agent.

  6. Ionic imbalance and lack of effect of adjuvant treatment with methylene blue in the hamster model of leptospirosis.

    PubMed

    Santos, Cleiton Silva; Azevedo, Everton Cruz de; Soares, Luciane Marieta; Carvalho, Magda Oliveira Seixas; dos Santos, Andréia Carvalho; das Chagas, Adenizar Delgado; da Silva, Caroline Luane Rabelo; Chagas, Ursula Maira Russo; dos Reis, Mitermayer Galvão; Athanazio, Daniel Abensur

    2013-06-01

    Leptospirosis in humans usually involves hypokalaemia and hypomagnesaemia and the putative mechanism underlying such ionic imbalances may be related to nitric oxide (NO) production. We previously demonstrated the correlation between serum levels of NO and the severity of renal disease in patients with severe leptospirosis. Methylene blue inhibits soluble guanylyl cyclase (downstream of the action of any NO synthase isoforms) and was recently reported to have beneficial effects on clinical and experimental sepsis. We investigated the occurrence of serum ionic changes in experimental leptospirosis at various time points (4, 8, 16 and 28 days) in a hamster model. We also determined the effect of methylene blue treatment when administered as an adjuvant therapy, combined with late initiation of standard antibiotic (ampicillin) treatment. Hypokalaemia was not reproduced in this model: all of the groups developed increased levels of serum potassium (K). Furthermore, hypermagnesaemia, rather than magnesium (Mg) depletion, was observed in this hamster model of acute infection. These findings may be associated with an accelerated progression to acute renal failure. Adjuvant treatment with methylene blue had no effect on survival or serum Mg and K levels during acute-phase leptospirosis in hamsters.

  7. Quantification of metabolically active biomass using Methylene Blue dye Reduction Test (MBRT): measurement of CFU in about 200 s.

    PubMed

    Bapat, Prashant; Nandy, Subir Kumar; Wangikar, Pramod; Venkatesh, K V

    2006-04-01

    Quantification of viable cells is a critical step in almost all biological experiments. Despite its importance, the methods developed so far to differentiate between viable and non-viable cells suffer from major limitations such as being time intensive, inaccurate and expensive. Here, we present a method to quantify viable cells based on reduction of methylene blue dye in cell cultures. Although the methylene blue reduction method is well known to check the bacterial load in milk, its application in the quantification of viable cells has not been reported. We have developed and standardized this method by monitoring the dye reduction rate at each time point for growth of Escherichia coli. The standard growth curve was monitored using this technique. The Methylene Blue dye Reduction Test (MBRT) correlates very well with Colony Forming Units (CFU) up to a 800 live cells as established by plating. The test developed is simple, accurate and fast (200 s) as compared to available techniques. We demonstrate the utility of the developed assay to monitor CFU rapidly and accurately for E. coli, Bacillus subtilis and a mixed culture of E. coli and B. subtilis. This assay, thus, has a wide applicability to all types of aerobic organisms.

  8. Post-Session Administration of USP Methylene Blue Facilitates the Retention of Pathological Fear Extinction and Contextual Memory in Phobic Adults

    PubMed Central

    Telch, Michael J.; Bruchey, Aleksandra K.; Rosenfield, David; Cobb, Adam R.; Smits, Jasper; Pahl, Sandra; Gonzalez-Lima, F.

    2015-01-01

    Objective Preclinical studies have shown that low-dose USP methylene blue increases mitochondrial cytochrome oxidase activity in the brain and improves memory retention after learning tasks, including fear extinction. We report on the first controlled experiment to examine the memory-enhancing effects of post-training methylene blue administration on retention of fear extinction and contextual memory following fear extinction training. Method Adults (N = 42) displaying marked claustrophobic fear were randomized to double-blind administration of 260 mg of methylene blue versus placebo immediately following six five-minute extinction trials to an enclosed chamber. Retesting occurred one month later to assess fear renewal as indexed by peak fear during exposure to a non-trained enclosed chamber with the prediction that methylene blue's effects would vary as a function of fear reduction achieved during extinction training. Incidental contextual memory was assessed 1 and 30 days after training to assess the cognitive enhancing effects of methylene blue independent of its effects on fear attenuation. Results Consistent with predictions, participants displaying low end fear at post-training showed significantly less fear at follow-up if they received methylene blue post-training relative to placebo. In contrast, participants displaying moderate to high levels of post-training fear tended to fare worse at follow-up relative to placebo. Methylene blue's enhancement of contextual memory was unrelated to initial or post-training claustrophobic fear. Conclusions Methylene blue enhances memory and the retention of fear extinction when administered after a successful exposure session, but may have a deleterious effect on extinction when administered after an unsuccessful exposure session. PMID:25018057

  9. Treatment and toxicity evaluation of methylene blue using electrochemical oxidation, fly ash adsorption and combined electrochemical oxidation-fly ash adsorption.

    PubMed

    Wang, Kai-sung; Wei, Ming-Chi; Peng, Tzu-Huan; Li, Heng-Ching; Chao, Shu-Ju; Hsu, Tzu-Fang; Lee, Hong-Shen; Chang, Shih-Hsien

    2010-08-01

    Treatment of a basic dye, methylene blue, by electrochemical oxidation, fly ash adsorption, and combined electrochemical oxidation-fly ash adsorption was compared. Methylene blue at 100 mgL(-1) was used in this study. The toxicity was also monitored by the Vibrio fischeri light inhibition test. When electrochemical oxidation was used, 99% color and 84% COD were removed from the methylene blue solution in 20 min at a current density of 428 Am(-2), NaCl of 1000 mgL(-1), and pH(0) of 7. However, the decolorized solution showed high toxicity (100% light inhibition). For fly ash adsorption, a high dose of fly ash (>20,000 mgL(-1)) was needed to remove methylene blue, and the Freundlich isotherm described the adsorption behavior well. In the combined electrochemical oxidation-fly ash adsorption treatment, the addition of 4000 mgL(-1) fly ash effectively reduced intermediate toxicity and decreased the COD of the electrochemical oxidation-treated methylene blue solution. The results indicated that the combined process effectively removed color, COD, and intermediate toxicity of the methylene blue solution.

  10. On the nature of patterns arising during polymerization of acrylamide in the presence of the methylene blue-sulfide-oxygen oscillating reaction

    NASA Astrophysics Data System (ADS)

    Kurin-Csörgei, Krisztina; Orbán, Miklós; Zhabotinsky, Anatol M.; Epstein, Irving R.

    1998-10-01

    Transient Turing-like spatial patterns were recently reported by Münster et al. when the components of the methylene blue oscillator are mixed with acrylamide and a polymerization initiator to form a polyacrylamide gel. We have qualitatively reproduced these results, but we demonstrate that, although the observed patterns have the appearance of Turing structures, they actually result from Rayleigh-Benard convection in a mixture of acrylamide, N,N'-methylene-bisacrylamide, triethanolamide, sulfide ions and ammonium peroxodisulfate during the polymerization and gelation process. Neither methylene blue nor sulfite is required for patterns to develop.

  11. Comparison of the photodynamic fungicidal efficacy of methylene blue, toluidine blue, malachite green and low-power laser irradiation alone against Candida albicans.

    PubMed

    Souza, Rodrigo C; Junqueira, Juliana Campos; Rossoni, Rodnei D; Pereira, Cristiane A; Munin, Egberto; Jorge, Antonio O C

    2010-05-01

    This study was to evaluate specific effects of photodynamic therapy (energy density 15.8 J/cm(2), 26.3 J/cm(2) and 39.5 J/cm(2)) using methylene blue, toluidine blue and malachite green as photosensitizers and low-power laser irradiation on the viability of Candida albicans. Suspensions of C. albicans containing 10(6) cells/ml were standardized in a spectrophotometer. For each dye, 120 assays, divided into four groups according to the following experimental conditions, were carried out: laser irradiation in the presence of the photosensitizer; laser irradiation only; treatment with the photosensitizer only; no exposure to laser light or photosensitizer. Next, serial dilutions were prepared and seeded onto Sabouraud dextrose agar for the determination of the number of colony-forming units per milliliter (CFU/ml). The results were subjected to analysis of variance and the Tukey test (P < 0.05). Photodynamic therapy using the photosensitizers tested was effective in reducing the number of C. albicans.. The number of CFU/ml was reduced by between 0.54 log(10) and 3.07 log(10) and depended on the laser energy density used. Toluidine blue, methylene blue and malachite green were effective photosensitizers in antimicrobial photodynamic therapy against C. albicans, as was low-power laser irradiation alone.

  12. The hygiene and marketing of fresh cream as assessed by the methylene blue test

    PubMed Central

    Mogford, Hilary

    1971-01-01

    The hygiene and marketing of fresh cream in England and Wales was investigated by a working party of the Public Health Laboratory Service (PHLS) between 1 October 1968 and 31 July 1969. Thirty-one cream-producing dairies were visited and observations made in the light of the Code of Practice published by the Milk and Milk Products Technical Advisory Committee of the Ministry of Agriculture, Fisheries and Food, and the Scottish Home and Health Department. Suggestions are made in this report to strengthen the code. A total of 5184 samples of fresh cream comprising 4385 heat-treated, 282 clotted and 517 untreated were examined. Details of production, age of the cream, distance and mode of distribution along the retail chain were available for most samples, and this history was, as far as possible, related to the laboratory findings. In the laboratory the samples were examined by the methylene blue test, colony count, coliform and Escherichia coli I test and for pathogens. Staphylococcus aureus was grown from 59 out of 3417 samples of cream; 54 of these were from untreated cream. Phage typing indicated that a proportion of these strains were of animal, presumably bovine, origin. Other human pathogens isolated included one each of Salmonella typhimurium, Brucella abortus, E. coli type O126 and Clostridium welchii. It appeared that heat-treated cream was much better, bacteriologically, than untreated; and that large dairies, in general, had better premises, more hygienic methods of preparation and the advantages of mechanical filling and capping of cartons; thus they offered the consumer a better product, bacteriologically, than some of the smaller dairies. A statistical analysis of the results of the tests used showed the methylene blue test, in spite of some anomalies, to be of more use as a screening test than any of the others. As this test is cheap and easy to carry out, the working party thought that it should be the test of choice. In view of the known anomalies

  13. Mechanism of Methylene Blue adsorption on hybrid laponite-multi-walled carbon nanotube particles.

    PubMed

    Manilo, Maryna; Lebovka, Nikolai; Barany, Sandor

    2016-04-01

    The kinetics of adsorption and parameters of equilibrium adsorption of Methylene Blue (MB) on hybrid laponite-multi-walled carbon nanotube (NT) particles in aqueous suspensions were determined. The laponite platelets were used in order to facilitate disaggregation of NTs in aqueous suspensions and enhance the adsorption capacity of hybrid particles for MB. Experiments were performed at room temperature (298 K), and the laponite/NT ratio (Xl) was varied in the range of 0-0.5. For elucidation of the mechanism of MB adsorption on hybrid particles, the electrical conductivity of the system as well as the electrokinetic potential of laponite-NT hybrid particles were measured. Three different stages in the kinetics of adsorption of MB on the surface of NTs or hybrid laponite-NT particles were discovered to be a fast initial stage I (adsorption time t=0-10 min), a slower intermediate stage II (up to t=120 min) and a long-lasting final stage III (up to t=24hr). The presence of these stages was explained accounting for different types of interactions between MB and adsorbent particles, as well as for the changes in the structure of aggregates of NT particles and the long-range processes of restructuring of laponite platelets on the surface of NTs. The analysis of experimental data on specific surface area versus the value of Xl evidenced in favor of the model with linear contacts between rigid laponite platelets and NTs. It was also concluded that electrostatic interactions control the first stage of adsorption at low MB concentrations.

  14. Clay mineral particles as effficient carriers of methylene blue used for antimicrobial treatment.

    PubMed

    Bujdák, Juraj; Jureceková, Jana; Bujdákova, Helena; Lang, Kamil; Sersen, Frantisek

    2009-08-15

    There is a strong demand to identify new strategies for disinfection and treatment of human, animal, and plant pathogens. The presented work shows the potential of clay minerals to contribute to the development of novel disinfection materials. Enhanced antimicrobial effect of a photoactive organic dye, methylene blue (MB), in the colloids of clay mineral was observed. Singlet oxygen (1O2) formed upon visible light irradiation was detected directly using luminescence measurements atthe near-infrared region and by spin-trapping method. While MB adsorbed on clay colloid particles lost the ability to produce 1O2 due to molecular aggregation, surprisingly, the antimicrobial activity was significantly enhanced. Under visible light irradiation, MB/clay minerals dispersions prevented the sporulation of A. niger and Penicillium sp. and inhibited the growth of C. albicans by an additional 6-15% when compared with MB solution. In the experiments with E. coli, the efficiency of MB was increased by the reduction of surviving cells by 27 and 33%. S. aureus proved to be the most susceptible to MB/clay dispersions. Only less than 20% cells survived with respect to the control experiment at the low MB concentration (1.1 x 10(-6) mol dm(-3)). The contradiction between the significant antimicrobial properties of MB in clay colloidal systems and low 1O2 formation can be explained in terms of the photosensitization mechanism. The role of clay particles is most likely to promote the contact between microorganism cells and photoactive MB. Although the dye directly bound to the clay surface exhibits significantly reduced photoactivity, the presence of clay mediates the delivery of dye molecules on the surface or inside cells. The results indicate new perspectives of potential implementations of clay minerals as parts of complex disinfection materials for industrial applications or in understanding similar processes in nature.

  15. Methylene blue prevents methylmalonate-induced seizures and oxidative damage in rat striatum.

    PubMed

    Furian, Ana Flávia; Fighera, Michele Rechia; Oliveira, Mauro Schneider; Ferreira, Ana Paula de Oliveira; Fiorenza, Natália Gindri; de Carvalho Myskiw, Jociane; Petry, João Carlos; Coelho, Rafael Correa; Mello, Carlos Fernando; Royes, Luiz Fernando Freire

    2007-01-01

    Methylene blue (MB) is a thiazine dye with cationic and lipophilic properties that acts as an electron transfer mediator in the mitochondria. Due to this metabolic improving activity and free radicals scavenging effects, MB has been used in the treatment of methemoglobinemia and ifosfamide-induced encephalopathy. Considering that methylmalonic acidemia consists of a group of inherited metabolic disorders biochemically characterized by impaired mitochondrial oxidative metabolism and reactive species production, we decided to investigate whether MB, protects against the behavioral and neurochemical alterations elicited by the intrastriatal injection of methylmalonate (MMA). In the present study we showed that intrastriatal injection of MB (0.015-1.5nmol/0.5microl) protected against seizures (evidenced by electrographic recording), protein carbonylation and Na(+),K(+)-ATPase inhibition ex vivo induced by MMA (4.5micromol/1.5microl). Furthermore, we investigated whether convulsions elicited by intrastriatal MMA administration are accompanied by striatal protein carbonyl content increase and changes in Na(+),K(+)-ATPase activity in rat striatum. The effect of MB (0.015-1.5nmol/0.5microl) and MMA (4.5micromol/0.5microl) on striatal NO(x) (NO(2) plus NO(3)) content was also evaluated. Statistical analysis revealed that the MMA-induced NO(x) content increase was attenuated by intrastriatal injection of MB and the duration of convulsive episodes correlated with Na(+),K(+)-ATPase inhibition, but not with MMA-induced total protein carbonylation. In view of that MB decreases MMA-induced neurotoxicity assessed by behavioral and neurochemical parameters, the authors suggest that MB may be of value to attenuate neurological deficits of methylmalonic acidemic patients.

  16. [Study on treatment of methylene blue wastewater by fly ash adsorption-Fenton and thermal regeneration].

    PubMed

    Bai, Yu-Jie; Zhang, Ai-Li; Zhou, Ji-Ti

    2012-07-01

    The physicochemical properties of water-washed fly ash (FA) and acid modified fly ash (M-FA) were investigated. The adsorption of methylene blue by FA and M-FA were studied by batch experiments. Two methods, Fenton-drive oxidation regeneration and thermal regeneration, were used for regeneration of the used FA and M-FA. The result showed that the rate of adsorption process followed the second order kinetics and the adsorption followed Langmuir isotherms. The adsorption equilibrium time was 30 min, and the equilibrium adsorption capacity of FA and M-FA were 4.22 mg x g(-1) and 5.98 mg x g(-1) respectively. The adsorption capability of M-FA was higher than that of FA. In the range of pH 2-12, the adsorption capacity of M-FA increased with the increase of pH, whereas the adsorption capacity of FA decreased slowly until the pH 8 and then increased. Electrostatic adsorption was the major factor on the adsorption capacity. Around 61% and 55% percentage regeneration (PR) were obtained for FA and M-FA respectively when 78.4 mmol x L(-1) H2O2 and 0.72 mmol x L(-1) Fe2+ were used. When the condition of thermal regeneration was 400 degrees C and 2 h, a positive correlation can be found between the PRs of FA and regeneration times, the PRs were 102%, 104% and 107% in three cycles of adsorption-thermal regeneration process. However a negative correlation can be found between the PRs of M-FA and regeneration times, the PRs were 82%, 75% and 74% in three cycles of adsorption-thermal regeneration process. The PR of FA was higher than that of M-FA, and thermal regeneration was superior to Fenton-drive regeneration.

  17. Adsorptive removal of methylene blue by rhamnolipid-functionalized graphene oxide from wastewater.

    PubMed

    Wu, Zhibin; Zhong, Hua; Yuan, Xingzhong; Wang, Hou; Wang, Lele; Chen, Xiaohong; Zeng, Guangming; Wu, Yan

    2014-12-15

    In this article, a rhamnolipid-functionalized graphene oxide (RL-GO) hybrid was prepared by one-step ultrasonication and adsorptive removal of methylene blue (MB) from both artificial and real wastewater by the RL-GO was investigated. The Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) area and Zeta potential analysis were used to characterize the adsorbent. The results showed that RL-GO had abundant functional groups and a mesopores feature. MB adsorption by the RL-GO increased with increase in adsorbent dose, pH, temperature and initial MB concentration, while it was insensitive to ionic strength variation. The adsorption kinetics fitted well to the pseudo-second-order model with correlation coefficients greater than 0.999. The Intra-particle diffusion and Boyd's film-diffusion models showed that the rate-controlled step was dominated by film-diffusion in the beginning and then followed by intra-particle diffusion. The adsorption isotherm was fitted by adsorption models with the suitability in order of BET > Freundlich > Langmuir > Temkin, based on comparison between correlation coefficients. Thermodynamic analysis of equilibriums suggested that the adsorption MB on RL-GO was spontaneous and endothermic. The adsorption mechanism was also proposed to be electrostatic attraction, π-π interaction and hydrogen bond. In addition, the real wastewater experiment, the regeneration study and the comparative cost analysis showed that the RL-GO composites could be a cost-effective and promising sorbent for MB wastewater treatment owing to its high efficiency and excellent reusability.

  18. A kinetic study of multiple H-attack on methylene blue in aqueous solution

    NASA Astrophysics Data System (ADS)

    Solar, S.; Getoff, N.; Solar, W.; Mark, F.

    The attack of H-atoms on several positions of the methylene blue molecule (5.10 -6-2.10 -5 mol dm -3 MB +) in acid aqueous solution (pH1) was investigated by pulse radiolysis. A least-squares fitting procedure was used for the determination of specific rate constants of these reactions as well as of ɛ-values of the resulting species. It was found that 88% of the H-atoms attacking MB +, with k = (1.2±0.1) × 10 10dm3mol-1s-1, lead to the formation of semiquinone (MBH 22+; SQ), which shows two absorption bands at 400 nm ( ɛ400 = 670 m2mol-1) and 880 nm ( ɛ880 = 1770 m2mol-1) and which decays by dismutation to MB + and leuco dye with 2 k = (2.0±0.3) × 10 9dm3mol-1s-1. 8% of the H-atoms attack the chromophore group with k = (1.1±0.2) × 10 9dm3mol-1s-1, leading to a species (R·) with ɛ400 = 5000 m2mol-1. This unspecified transient disappears probably by a pseudo-first order reaction, with k = (1.4±0.3) × 10 5s-1. The rest of the H-atoms (4%) form H-adducts on the aromatic rings with k(0.6±0.2) × 10 9dm 3mol -1s -1.

  19. Methylene Blue Removal by Biochars from Food Industry By-Products

    NASA Astrophysics Data System (ADS)

    Orfanos, Alexis; Manariotis, Ioannis D.; Karapanagioti, Hrissi K.

    2016-04-01

    Biomass produced by food industries is mainly used as feedstock or in composting. In recent years, considerable research effort has been focused on the production of biochar under oxygen-limited conditions from carbon-rich biomass, such as food industry by-products, as mitigation measure for global warming once it is used as a soil amendment. The present study presents the findings of an experimental work, which investigated the use of different biochars for the removal of methylene blue (MB) from aqueous solutions. Biochars were produced from malt spent rootlets (MSR) from brewering and espresso coffee residue from coffee shops. MSR was pyrolyzed at temperatures of 300, 400, 500, 750, 850, and 900oC and the coffee residue was pyrolyzed at 850oC. The charring process was performed under limited-oxygen conditions using specialized containers. The surface area and the porosity of the materials were determined. Batch experiments were conducted in order to evaluate the sorption capacity of the above materials, and samples were agitated for 24 h at 25oC, at an optimum pH of about 7. Kinetic analysis was conducted over a period of 24 h, and isotherm studies were also constructed. The surface area of biochar produced from MSR and the MB removal were considerably increased at pyrolysis temperatures higher than 500oC. At 850oC, the maximum surface area value (300 m2 g-1) was observed, and the MB sorption capacity was 99 mg g-1. Based on the kinetic experimental data, sorption capacities at 120 min were over 58% of their equilibrium values for the biochars used. The maximum MB sorption capacity, based on the isotherm data, was 130 mg g-1, for the two biochars employed.

  20. sup 211 At-methylene blue for targeted radiotherapy of human melanoma xenografts: Treatment of micrometastases

    SciTech Connect

    Link, E.M.; Carpenter, R.N. )

    1990-05-15

    Treatment of micrometastases of HX34 human melanoma grown as xenografts in nude mice represents an advanced stage of preclinical investigations concerning targeted radiotherapy of this neoplasm using 3,7-(dimethylamino)phenazathionium chloride methylene blue (MTB) labeled with astatine-211 (211At) (alpha-particle emitter). The therapeutic effectiveness of 211At-MTB administered i.v. was determined by a lung colony assay combined with a search for metastases to organs other than the lungs. A single dose of 211At-MTB lowered the HX34 cell surviving fraction in lungs to below 10% almost independently of the time interval between cell inoculation and radioisotope injection and of 211At-MTB radioactivity within its investigated range. Radiation dose and the time of its administration did, however, influence the size of lung colonies. In contrast, the efficacy of 211At-MTB treatment as assessed by both surviving fraction and colony size was significantly dependent on a number of HX34 cells inoculated initially into mice. These results are explained by a short range of alpha-particles emitted by 211At and a mechanism of growth of lung colonies from tumor cells circulating with blood and blocking lung capillaries. Metastases in organs other than lungs and characteristic of control animals were not found in mice treated with 211At-MTB. The high therapeutic efficacy achieved proved that 211At-MTB is a very efficient scavenger of single melanoma cells distributed through blood and micrometastases with sizes below the limit of clinical detection.