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Gunter Heisler - One of the best experts on this subject based on the ideXlab platform.
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the photo Fenton Reaction an effective photochemical wastewater treatment process
Journal of Photochemistry and Photobiology A-chemistry, 1993Co-Authors: G Ruppert, Rupert Bauer, Gunter HeislerAbstract:Abstract A novel photochemical degradation method for organic contaminants, the photo-Fenton Reaction, has been investigated. Irradiation of an aqueous solution of 4-chlorophenol (4-CP) with light of greater than 320 nm in the presence of H 2 O 2 and Fe 2+ accelerates the degradation rate of 4-CP and total organic carbon (TOC) significantly compared with the Fe 2+ H 2 O 2 Reaction in the dark. The effects of the initial 4-CP and H 2 O 2 concentrations and the intensity of light irradiation on the degradation rates of TOC and H 2 O 2 and the ratio of Fe 2+ to Fe 3+ are described. Results are compared with the dark Fenton Reaction.
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The photo-Fenton Reaction — an effective photochemical wastewater treatment process
Journal of Photochemistry and Photobiology A: Chemistry, 1993Co-Authors: G Ruppert, Rupert Bauer, Gunter HeislerAbstract:Abstract A novel photochemical degradation method for organic contaminants, the photo-Fenton Reaction, has been investigated. Irradiation of an aqueous solution of 4-chlorophenol (4-CP) with light of greater than 320 nm in the presence of H2O2 and Fe2+ accelerates the degradation rate of 4-CP and total organic carbon (TOC) significantly compared with the Fe2+H2O2 Reaction in the dark. The effects of the initial 4-CP and H2O2 concentrations and the intensity of light irradiation on the degradation rates of TOC and H2O2 and the ratio of Fe2+ to Fe3+ are described. Results are compared with the dark Fenton Reaction.
Dan Meyerstein - One of the best experts on this subject based on the ideXlab platform.
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The FeII(citrate) Fenton Reaction under physiological conditions.
Journal of inorganic biochemistry, 2020Co-Authors: Erzsébet Illés, Shanti G. Patra, Vered Marks, Amir Mizrahi, Dan MeyersteinAbstract:Abstract The Fenton Reaction of FeII(citrate) in the presence and absence of bicarbonate (HCO3−) is studied. It is found that the rate constant of the Fenton Reaction (kobs) increases with increasing [citrate]. kobs also increase with increasing [HCO3−]; this effect is most significant at biological citrate concentrations. Methane and ethane gases are formed from (CH3)2SO when the Fenton Reaction is carried out in the presence of large [citrate] due to the Reaction of the citrate radical, (−2OC)CH2C(OH)(CO2−)CH(CO2−) /(−2OC)CH2C(O)(CO2−)CH2(CO2−) with (CH3)2SO. In the absence of citrate (CH3)2SO2 is the main product of the Fenton Reaction. However, in the presence of 0.10 mM citrate, no (CH3)2SO2 is formed, some (CH3)SOOH is formed, along with a low yield of beta-ketoglutaric acid. Formation of (CH3)SOOH and beta-ketoglutaric acid are due to the citrate radical and FeIV(citrate). In the presence of bicarbonate formation of abundant beta-ketoglutaric acid confirms the formation of carbonate radical anion (CO3 −). Thus, bicarbonate affects the mechanism and kinetics of the Reaction dramatically. Hydroxyl radicals (OH ) are not formed in the presence of bicarbonate and probably also not in its absence. These results point out that hydroxyl radicals, formed by the Fenton Reaction, do not initiate oxidative stress in biological systems.
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The effect of pyrophosphate, tripolyphosphate and ATP on the rate of the Fenton Reaction.
Journal of inorganic biochemistry, 2011Co-Authors: Sandra Rachmilovich‐calis, Alexandra Masarwa, Naomi Meyerstein, Dan MeyersteinAbstract:Abstract It has been recently reported that pyrophosphate, tri-polyphosphate, ATP and analogous ligands considerably decrease the yield of hydroxyl radicals by the Fenton Reaction under conditions where [H 2 O 2 ] > > [Fe(II)L n ]. It was suggested that this effect is due to the slowing down of the Fenton Reaction by these ligands. This suggestion seemed surprising as polyphosphate ligands stabilize Fe(III). Indeed, a kinetic study points out that these ligands accelerate the rate of the Fenton Reaction by several orders of magnitude. Thus it is suggested that the effect of the ligands on the yield of the hydroxyl radicals is due to the stabilization of the Fe(III) complexes which slows down, or inhibits, their reduction by the radicals formed in the system and thus decreases the overall yield of hydroxyl radicals.
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New mechanistic aspects of the Fenton Reaction.
Chemistry (Weinheim an der Bergstrasse Germany), 2009Co-Authors: Sandra Rachmilovich‐calis, Alexandra Masarwa, Naomi Meyerstein, Dan Meyerstein, Rudi Van EldikAbstract:The kinetics of the Fenton Reaction was studied in detail. A second Reaction step in the presence of excess H2O2 is attributed to formation of the complex Fe(III)(-O2H)(aq). Therefore, the Reaction of Fe(H2O)(6)(2+) with Fe(III)(-O2H)(aq) in the presence of Fe(II) to form Fe(III)(aq) (k=(7.7+/-1.5) x 10(5) M(-1) s(-1)) may contribute to the overall Fenton Reaction, and could account for some of the debate in the literature concerning its detailed mechanism. If this is correct for LFe(III)(-O2H)(aq) also, then it might be of significant biological importance. The activation parameters DeltaH(not equal), DeltaS(not equal), and DeltaV(not equal) for the Fenton Reaction were measured under various experimental conditions, and are used in the mechanistic interpretation.
G Ruppert - One of the best experts on this subject based on the ideXlab platform.
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the photo Fenton Reaction an effective photochemical wastewater treatment process
Journal of Photochemistry and Photobiology A-chemistry, 1993Co-Authors: G Ruppert, Rupert Bauer, Gunter HeislerAbstract:Abstract A novel photochemical degradation method for organic contaminants, the photo-Fenton Reaction, has been investigated. Irradiation of an aqueous solution of 4-chlorophenol (4-CP) with light of greater than 320 nm in the presence of H 2 O 2 and Fe 2+ accelerates the degradation rate of 4-CP and total organic carbon (TOC) significantly compared with the Fe 2+ H 2 O 2 Reaction in the dark. The effects of the initial 4-CP and H 2 O 2 concentrations and the intensity of light irradiation on the degradation rates of TOC and H 2 O 2 and the ratio of Fe 2+ to Fe 3+ are described. Results are compared with the dark Fenton Reaction.
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The photo-Fenton Reaction — an effective photochemical wastewater treatment process
Journal of Photochemistry and Photobiology A: Chemistry, 1993Co-Authors: G Ruppert, Rupert Bauer, Gunter HeislerAbstract:Abstract A novel photochemical degradation method for organic contaminants, the photo-Fenton Reaction, has been investigated. Irradiation of an aqueous solution of 4-chlorophenol (4-CP) with light of greater than 320 nm in the presence of H2O2 and Fe2+ accelerates the degradation rate of 4-CP and total organic carbon (TOC) significantly compared with the Fe2+H2O2 Reaction in the dark. The effects of the initial 4-CP and H2O2 concentrations and the intensity of light irradiation on the degradation rates of TOC and H2O2 and the ratio of Fe2+ to Fe3+ are described. Results are compared with the dark Fenton Reaction.
Kyoung Heon Kim - One of the best experts on this subject based on the ideXlab platform.
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mimicking the Fenton Reaction induced wood decay by fungi for pretreatment of lignocellulose
Bioresource Technology, 2015Co-Authors: Young Hoon Jung, Hyun Kyung Kim, Hyun Min Park, Yongcheol Park, Kyungmoon Park, Jinho Seo, Kyoung Heon KimAbstract:Abstract In this study, the Fenton Reaction, which is naturally used by fungi for wood decay, was employed to pretreat rice straw and increase the enzymatic digestibility for the saccharification of lignocellulosic biomass. Using an optimized Fenton’s reagent (FeCl 3 and H 2 O 2 ) for pretreatment, an enzymatic digestibility that was 93.2% of the theoretical glucose yield was obtained. This is the first report of the application of the Fenton Reaction to lignocellulose pretreatment at a moderate temperature (i.e., 25 °C) and with a relatively high loading of biomass (i.e., 10% (w/v)). Substantial improvement in the process economics of cellulosic fuel and chemical production can be achieved by replacing the conventional pretreatment with this Fenton-mimicking process.
Thomas J. Dichristina - One of the best experts on this subject based on the ideXlab platform.
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simultaneous transformation of commingled trichloroethylene tetrachloroethylene and 1 4 dioxane by a microbially driven Fenton Reaction in batch liquid cultures
Applied and Environmental Microbiology, 2016Co-Authors: Ramanan Sekar, Martial Taillefert, Thomas J. DichristinaAbstract:ABSTRACT Improper disposal of 1,4-dioxane and the chlorinated organic solvents trichloroethylene (TCE) and tetrachloroethylene (also known as perchloroethylene [PCE]) has resulted in widespread contamination of soil and groundwater. In the present study, a previously designed microbially driven Fenton Reaction system was reconfigured to generate hydroxyl (HO˙) radicals for simultaneous transformation of source zone levels of single, binary, and ternary mixtures of TCE, PCE, and 1,4-dioxane. The reconfigured Fenton Reaction system was driven by fed batch cultures of the Fe(III)-reducing facultative anaerobe Shewanella oneidensis amended with lactate, Fe(III), and contaminants and exposed to alternating anaerobic and aerobic conditions. To avoid contaminant loss due to volatility, the Fe(II)-generating, hydrogen peroxide-generating, and contaminant transformation phases of the microbially driven Fenton Reaction system were separated. The reconfigured Fenton Reaction system transformed TCE, PCE, and 1,4-dioxane either as single contaminants or as binary and ternary mixtures. In the presence of equimolar concentrations of PCE and TCE, the ratio of the experimentally derived rates of PCE and TCE transformation was nearly identical to the ratio of the corresponding HO˙ radical Reaction rate constants. The reconfigured Fenton Reaction system may be applied as an ex situ platform for simultaneous degradation of commingled TCE, PCE, and 1,4-dioxane and provides valuable information for future development of in situ remediation technologies. IMPORTANCE A microbially driven Fenton Reaction system [driven by the Fe(III)-reducing facultative anaerobe S. oneidensis] was reconfigured to transform source zone levels of TCE, PCE, and 1,4-dioxane as single contaminants or as binary and ternary mixtures. The microbially driven Fenton Reaction may thus be applied as an ex situ platform for simultaneous degradation of at least three (and potentially more) commingled contaminants. Additional targets for ex situ and in situ degradation by the microbially driven Fenton Reaction developed in the present study include multiple combinations of environmental contaminants susceptible to attack by Fenton Reaction-generated HO˙ radicals, including commingled plumes of 1,4-dioxane, pentachlorophenol (PCP), PCE, TCE, 1,1,2-trichloroethane (TCA), and perfluoroalkylated substances (PFAS).
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Microbially Driven Fenton Reaction for Degradation of the Widespread Environmental Contaminant 1,4-Dioxane
Environmental Science & Technology, 2014Co-Authors: Ramanan Sekar, Thomas J. DichristinaAbstract:The carcinogenic cyclic ether compound 1,4-dioxane is employed as a stabilizer of chlorinated industrial solvents and is a widespread environmental contaminant in surface water and groundwater. In the present study, a microbially driven Fenton Reaction was designed to autocatalytically generate hydroxyl (HO•) radicals that degrade 1,4-dioxane. In comparison to conventional (purely abiotic) Fenton Reactions, the microbially driven Fenton Reaction operated at circumneutral pH and did not the require addition of exogenous H2O2 or UV irradiation to regenerate Fe(II) as Fenton reagents. The 1,4-dioxane degradation process was driven by pure cultures of the Fe(III)-reducing facultative anaerobe Shewanella oneidensis manipulated under controlled laboratory conditions. S. oneidensis batch cultures were provided with lactate, Fe(III), and 1,4-dioxane and were exposed to alternating aerobic and anaerobic conditions. The microbially driven Fenton Reaction completely degraded 1,4-dioxane (10 mM initial concentration)...
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microbially driven Fenton Reaction for degradation of the widespread environmental contaminant 1 4 dioxane
Environmental Science & Technology, 2014Co-Authors: Ramanan Sekar, Thomas J. DichristinaAbstract:The carcinogenic cyclic ether compound 1,4-dioxane is employed as a stabilizer of chlorinated industrial solvents and is a widespread environmental contaminant in surface water and groundwater. In the present study, a microbially driven Fenton Reaction was designed to autocatalytically generate hydroxyl (HO•) radicals that degrade 1,4-dioxane. In comparison to conventional (purely abiotic) Fenton Reactions, the microbially driven Fenton Reaction operated at circumneutral pH and did not the require addition of exogenous H2O2 or UV irradiation to regenerate Fe(II) as Fenton reagents. The 1,4-dioxane degradation process was driven by pure cultures of the Fe(III)-reducing facultative anaerobe Shewanella oneidensis manipulated under controlled laboratory conditions. S. oneidensis batch cultures were provided with lactate, Fe(III), and 1,4-dioxane and were exposed to alternating aerobic and anaerobic conditions. The microbially driven Fenton Reaction completely degraded 1,4-dioxane (10 mM initial concentration) in 53 h with an optimal aerobic-anaerobic cycling period of 3 h. Acetate and oxalate were detected as transient intermediates during the microbially driven Fenton degradation of 1,4-dioxane, an indication that conventional and microbially driven Fenton degradation processes follow similar Reaction pathways. The microbially driven Fenton Reaction provides the foundation for development of alternative in situ remediation technologies to degrade environmental contaminants susceptible to attack by HO• radicals generated by the Fenton Reaction.