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Fenton's Reagent (fenton + reagent)
Selected AbstractsPhenol Removal through Chemical Oxidation using Fenton ReagentCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2007Y. Yavuz Abstract In this study, phenol, aromatic, and non-biodegradable organic matter were investigated and found to be removed from the model solution through chemical oxidation using Fenton reagent. The effects of the initial phenol concentration, hydrogen peroxide, and ferrous sulfate concentrations on the removal efficiency were investigated. Performance of the chemical oxidation process was monitored with phenol and COD (Chemical Oxygen Demand) analyses. In the experimental studies, phenol removal of over 98,% and COD removal of nearly 70,% were achieved. The optimum conditions for Fenton reaction both for initial phenol concentrations of 200 and 500,mg/L were found at a ratio [Fe2+]/[H2O2] (mol/mol) equal to 0.11. According to the results, chemical oxidation using Fenton reagent was found to be too effective, especially for phenol removal. However, this method has limited removal efficiency for COD. [source] Synthesis and characterization of polyaniline films using Fenton reagentJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008M. M. Ayad Abstract The chemical oxidation of aniline to form polyaniline (PANI) films and powder samples was made using Fenton reagent as an oxidizing agent in aqueous sulfuric acid medium. The PANI films were monitored by using the quartz crystal microbalance and the electronic absorption techniques. The optimum concentration was determined and the results were justified by measuring the UV,vis absorption spectra for the in situ PANI films. The conductivity for the PANI films and powder samples, prepared in different conditions, was measured. Also, the IR spectra, X-ray and the thermogravimetric analysis for the PANI powder formed in the bulk were measured and compared with the polymer prepared using ammonium peroxydisulfate. A preliminary investigation to the dielectric properties of the polymer powder was measured and discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] A fluorimetric method for the determination of trace pentachlorophenol, based on its inhibitory effect on the redox reaction between the improved Fenton reagent and rhodamine BLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 5 2007Huiqin Guo Abstract A sensitive fluorimetric method is presented and discussed for the determination of pentachlorophenol in aqueous solutions. This method is based on the inhibitory effect of pentachlorophenol on the reaction of conventional Fenton [Fe(III) + H2O2] reagent with rhodamine B in the medium of perchloric acid, which results in the fluorescence quenching of rhodamine B. It was further found that the sensitivity for the determination was improved significantly when the molecular ligand EDTA was added. This improved system was therefore presented for the determination of pentachlorophenol. The characteristics of the excitation and emission spectra, optimization of the experimental conditions, the stability of the system and the influence of foreign matter have all been investigated. Under optimal conditions, the linear range for the determination of pentachlorophenol is 12,480 ng/mL with a 3, limit of detection of 0.96 ng/mL. Compared with the conventional Fenton system, the improved system shows obvious advantages in both sensitivity and selectivity. By combination with the pretreatment of samples using ion exchange resins and XDA-1 absorption resin, the improved Fenton method was used for the first time for the determination of pentachlorophenol in synthetic samples and natural water samples, and satisfactory results, in agreement with those of the HPLC method, were achieved. The possible mechanism of the reactions has also been discussed. Copyright © 2007 John Wiley & Sons, Ltd. [source] Phenol Removal through Chemical Oxidation using Fenton ReagentCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2007Y. Yavuz Abstract In this study, phenol, aromatic, and non-biodegradable organic matter were investigated and found to be removed from the model solution through chemical oxidation using Fenton reagent. The effects of the initial phenol concentration, hydrogen peroxide, and ferrous sulfate concentrations on the removal efficiency were investigated. Performance of the chemical oxidation process was monitored with phenol and COD (Chemical Oxygen Demand) analyses. In the experimental studies, phenol removal of over 98,% and COD removal of nearly 70,% were achieved. The optimum conditions for Fenton reaction both for initial phenol concentrations of 200 and 500,mg/L were found at a ratio [Fe2+]/[H2O2] (mol/mol) equal to 0.11. According to the results, chemical oxidation using Fenton reagent was found to be too effective, especially for phenol removal. However, this method has limited removal efficiency for COD. [source] Soil Vapor Extraction and Chemical Oxidation to Remediate Chlorinated Solvents in Fractured Crystalline Bedrock: Pilot Study Results and Lessons LearnedREMEDIATION, Issue 2 2002H. Jean Cho A pilot study was completed at a fractured crystalline bedrock site using a combination of soil vapor extraction (SVE) and in-situ chemical oxidation (ISCO) with Fenton's Reagent. This system was designed to destroy 1,1,1-trichloroethane (TCA) and its daughter products, 1,1-dichloroethene (DCE) and 1,1-dichloroethane (DCA). Approximately 150 pounds of volatile organic compounds (VOCs) were oxidized in-situ or removed from the aquifer as vapor during the pilot study. Largely as a result of chemical oxidation, TCA concentrations in groundwater located within a local groundwater mound decreased by 69 to 95 percent. No significant rebound in VOC concentration was observed in these wells. Wells located outside of the groundwater mound showed less dramatic decreases in VOC concentration, and the data show that vapor stripping and short-term groundwater migration following the oxidant injection were the key processes at these wells. Although the porosity of the aquifer at the site is on the order of 2 percent or less, the pilot study showed that SVE could be an effective remedial process in fractured crystalline rock. © 2002 Wiley Periodicals, Inc. [source] Reaction kinetics for the degradation of phenol and chlorinated phenols using Fenton's reagentENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2006Asim K. De Abstract Fenton's reaction is an advanced treatment technology often used for the removal of hazardous and refractory organic compounds from industrial wastewaters. It can effectively be used to degrade phenol and chlorophenols. The initial contaminant concentrations as well as the concentration of hydrogen peroxide and ferrous ions in aqueous solution have a significant effect on the effective degradation of contaminants. For a particular concentration of initial substrate in solution there should be an optimum level of ferrous ion concentration in the reaction medium. Based on experimental observations, a probable mechanism for Fenton's degradation kinetics has been proposed and a rate equation developed. From the rate expression, OH· radical reaction rate constants for the degradation of three compounds,phenol and o- and p-chlorophenols,in Fenton reaction were calculated to have values of 2.53 × 107, 2.38 × 107, and 2.45 × 107 m3 mol,1 s,1, respectively. © 2005 American Institute of Chemical Engineers Environ Prog, 2005 [source] Kinetics of aerobic and anaerobic oxidations of ethanol by Fenton's reagentINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 9 2008Mordechai L. Kremer For the first time, the time dependence of [H2O2] and [Fe2+] was followed during the aerobic oxidation of ethanol by Fenton's reagent. It was found that part of the ethanol was oxidized by dissolved O2 via the transient formation of H2O2. A model was set up based on FeO2+ as the key intermediate. Both one- and two-equivalent oxidations of ethanol occur, the former producing radical species derived from ethanol. No free radicals derived from H2O2 play part in the system. The relevant rate constants or their ratios were determined. The mechanism accounted successfully also for the anaerobic oxidation of ethanol. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 541,553, 2008 [source] Advanced oxidation of cork-processing wastewater using Fenton's reagent: kinetics and stoichiometryJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2004Jesús Beltrán de Heredia Abstract This work evaluates Fenton oxidation for the removal of organic matter (COD) from cork-processing wastewater. The experimental variables studied were the dosages of iron salts and hydrogen peroxide. The COD removal ranged from 17% to 79%, depending on the reagent dose, and the stoichiometric reaction coefficient varied from 0.08 to 0.43 g COD (g H2O2),1 (which implies an efficiency in the use of hydrogen peroxide varying from 17% to 92%). In a study of the process kinetics, based on the initial rates method, the COD elimination rate was maximum when the molar ratio [H2O2]o:[Fe2+]o was equal to 10. Under these experimental conditions, the initial oxidation rate was 50.5 mg COD dm,3 s,1 with a rate of consumption of hydrogen peroxide of 140 mg H2O2 dm,3 s,1, implying an efficiency in the use of the hydrogen peroxide at the initial time of 77%. The total amount of organic matter removed by Fenton oxidation was increased by spreading the H2O2 and ferrous salt reagent over several fractions by 15% for two-fractions and by 21% for three-fractions. Copyright © 2004 Society of Chemical Industry [source] Decolourisation of aqueous dyes by sequential oxidation treatment with ozone and Fenton's reagentJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2002M Mahbubul Hassan Abstract Combined oxidation with ozone and Fenton's reagent (,Fentozone' process) for decolourisation of aqueous dyes was studied and compared with traditional Fenton's reagent. Although the ,Fentozone' process was found to be effective at a wide range of pH values, the maximum colour removal was achieved at pH 4. The effect of pre-ozonation on colour removal efficiency of aqueous dyestuffs in the subsequent treatment with Fenton's reagent was investigated. The reaction kinetics using water-soluble acid and reactive dyes were also studied. Our experimental results show that pre-ozonation can considerably accelerate decomposition of dyestuffs in the subsequent treatment with Fenton's reagent. Different concentrations of ferrous sulfate were used to investigate their influences on the removal of colour. The rate of reaction increased with increasing doses of ferrous sulfate. © 2002 Society of Chemical Industry [source] Remedial options for chlorinated volatile organics in a partially anaerobic aquiferREMEDIATION, Issue 4 2004Xiujin Qiu A laboratory study was conducted for the selection of appropriate remedial technologies for a partially anaerobic aquifer contaminated with chlorinated volatile organics (VOCs). Evaluation of in situ bioremediation demonstrated that the addition of electron donors to anaerobic microcosms enhanced biological reductive dechlorination of tetrachloroethene (PCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1-TCA) with half-lives of 20, 22, and 41 days, respectively. Nearly complete reductions of PCE, TCE, 1,1,1-TCA, and the derivative cis-dichloroethene were accompanied by a corresponding increase in chloride concentrations. Accumulation of vinyl chloride, ethene, and ethane was not observed; however, elevated levels of 14CO2 (from 14C-TCE spiked) were recovered, indicating the occurrence of anaerobic oxidation. In contrast, very little degradation of 1,2-dichloropropane (1,2-DCP) and 1,1-dichlorethane (1,1-DCA) was observed in the anaerobic microcosms, but nutrient addition enhanced their degradation in the aerobic biotic microcosms. The aerobic degradation half-lives for 1,2-DCP and 1,1-DCA were 63 and 56 days, respectively. Evaluation of in situ chemical oxidation (ISCO) demonstrated that chelate-modified Fenton's reagent was effective in degrading aqueous-phase PCE, TCE, 1,1,1-TCA, 1,2-DCP, etc.; however, this approach had minimal effects on solid-phase contaminants. The observed oxidant demand was 16 g-H2O2/L-groundwater. The oxidation reaction rates were not highly sensitive to the molar ratio of H2O2:Fe2+:citrate. A ratio of 60:1:1 resulted in slightly faster removal of chemicals of concern (COCs) than those of 12:1:1 and 300:1:1. This treatment resulted in increases in dissolved metals (Ca, Cr, Mg, K, and Mn) and a minor increase of vinyl chloride. Treatment with zero-valent iron (ZVI) resulted in complete dechlorination of PCE, and TCE to ethene and ethane. ZVI treatment reduced 1,1,1-TCA only to 1,1-DCA and chloroethane (CA) but had little effect on reducing the levels of 1,2-DCP, 1,1-DCA, and CA. The longevity test showed that one gram of 325-mesh iron powder was exhausted in reaction with > 22 mL of groundwater. The short life of ZVI may be a barrier to implementation. The ZVI surface reaction rates (ksa) were 1.2 × 10,2 Lm,2h,1, 2 × 10,3 Lm,2h,1, and 1.2 × 10,3 Lm,2h,1 for 1,1,1-TCA, TCE, and PCE, respectively. Based upon the results of this study, in situ bioremediation appeared to be more suitable than ISCO and ZVI for effectively treating the groundwater contamination at the site. © 2004 Wiley Periodicals, Inc. [source] | ||||||||||