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dechlorination of 2,2＇,4,4＇,5,5＇-hexachlorobiphenyl by thermal reaction with activated carbon-supported copper or zinc

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Frontiers of Environmental Science & Engineering 2013年第6期7卷 827-832页

作者： Yifei SUN Xin FU Wei QIAO Wei WANG Tianle ZHU Xinghua LI School of Chemistry and Environment Beihang University Beijing 100191 China College of Chemical Science and Engineering China University of Petroleum Beijing 102249 China School of Environment Tsinghua University Beijing 100084 China

Activated carbon （AC）-supported copper or zinc made from ion exchange resin （IRCu-C and IRZn-C） have an increased metal load of 557.3 mg·g^-1 and 502.8 mg·g^-1 compared to those prepared by the traditional method involving impregnation with AC and copper （II） citrate or zinc citrate solution （LaCu-C and LaZn-C） of 12.9 mg·g^-1 and 46.0 mg·g^-1 respectively. When applied to decompose 2,2＇,4,4＇,5,5＇-hexachlorobiphenyl at 250 ℃, IRCu-C achieved higher activity of 99.0% decomposition efficiency than LaCu-C of 84.7%, IRZn-C of 90.5% and LaZn-C of 62.7%. When the reaction temperature rose to 350 ℃, all the four kinds of reactants can decompose PCB- 153 with efficiency above 90%. Further, X-ray photoelec- tron spectroscopy characterization of IRCu-C before and after the reaction indicated transformation of 19.1% of Cu atoms into Cu^2＋, illustrating that Cu is the active ingredient or electron donor promoting the decomposition of PCB- 153. The mechanism underlying this process differs from a traditional H donor. However, there is no significant change on the surface of IRZn-C before and after the reaction, suggesting that Zn acts as catalyst during the process of PCB-153 decomposition.

关键词： polychlorinated biphenyls activated carbon-supported copper or zinc dechlorination electron donor

dechlorination of disinfection by-product monochloroacetic acid in drinking water by nanoscale palladized iron bimetallic particle

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Journal of Environmental Sciences 2008年第8期20卷 945-951页

作者： CHEN, Chao WANG, Xiangyu CHANG, Ying LIU, Huiling State Key Laboratory of Urban Water Resources and Environment Harbin Institute of Technology Harbin 150090 China Department of Environmental Science and Engineering School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China

Nanoscale palladized iron(Pd/Fe)bimetallic particles were prepared by reductive deposition *** particles were characterized by X-ray diffraction(XRD),X-ray fluorescence(XRF),scanning electron microscope(SEM),transmission electron microscope(TEM),and Brunauer-Emmett-Teller-nitrogen(BET-N_2)*** obtained from those methods indicated that nanoscale Pd/Fe bimetallic particles containedα-Fe^*** Pd to Fe ratio by weight(Pd/Fe ratio)was close to theoretical value. Spherical granules with diame...

关键词： nanoscale Pd/Fe bimetallic particles dechlorination monochloroacetic acid

dechlorination of Crude Oil by Phase Transfer Catalyst via Nucleophilic Substitution Reaction

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China Petroleum Processing & Petrochemical Technology 2021年第4期23卷 18-28页

作者： Gu Jin Han Xin Liu Jichang Huang Zihao Xing Biao State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237 Key Laboratory for Green Processing of Chemical Engineering of Xinjiang Bingtuan School of Chemistry and Chemical EngineeringShihezi UniversityShihezi 832003

dechlorination of crude oil is an effective way to alleviate corrosion in refinery units,and the critical process is the removal of organochlorine which can be efficiently removed through nucleophilic substitution reaction catalyzed by phase ***,seven typical chlorinated alkanes were selected as model compounds to study the mechanism of dechlorination of crude oil by phase transfer catalyst in the nucleophilic substitution method,and a new dechlorination reagent using hexamethyl quaternary ammonium hydroxide(HMQAH)with two quaternary ammonium groups as phase transfer catalyst,ethylenediamine as nucleophile and ethanol as solvent was *** results show that the dechlorinating performance of the dechlorination reagent on the model compounds decreases in the following order:epichlorohydrin>1,2-dichlorobutane>1,2-dichloroethane>1,3-dichloropropane>2-chloropropane>1-chlorobutane>*** the results of the reaction kinetics show that epichlorohydrin with epoxy structure has the lowest activation energy in the process of nucleophilic substitution reaction by the phase transfer catalyst which makes it easier to be removed by the dechlorination *** removal rate of epichlorohydrin can reach up to 99.4%.The optimal dechlorination reagent used ethylenediamine as nucleophile,ethanol as solvent and HMQAH as phase transfer *** dechlorinating rate of the Iranian crude oil reached 71.6%under conditions covering a reaction temperature of 95℃,a reaction time of 90 minutes,a dechlorination reagent dosage of 1000μg/g,and a phase transfer reagent/nucleophile molar ratio of 6:*** addition,the mechanism of phase transfer in nucleophilic substitution reaction of chloroalkanes was investigated in the paper.

关键词： model compounds phase transfer nucleophilic substitution dechlorination Iranian crude oil

Humic acid and metal ions accelerating the dechlorination of 4-chlorobiphenyl by nanoscale zero-valent iron

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Journal of Environmental Sciences 2011年第8期23卷 1286-1292页

作者： Yu Wang Dongmei Zhou Yujun Wang Xiangdong Zhu Shengyang Jin State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Transformation of polychlorinated biphenyls （PCBs） by zero-valent iron represents one of the latest innovative technologies for environmental remediation. The dechlorination of 4-chlorobiphenyl （4-C1BP） by nanoscale zero-valent iron （NZVI） in the presence of humic acid or metal ions was investigated. The results showed that the dechlorination of 4-C1BP by NZVI increased with decreased solution pH. When the initial pH value was 4.0, 5.5, 6.8, and 9.0, the *** efficiencies of 4-CIBP after 48 hr were 53.8%, 47.8%, 35.7%, and 35.6%, respectively. The presence of humic acid inhibited the reduction of 4-CIBP in the first 4 hi＇, and then significantly accelerated the dechlorination by reaching 86.3% in 48 hr. Divalent metal ions, Co2＋, Cu2＋, and Ni2＋, were reduced and formed bimetals with NZVI, thereby enhanced the dechlorination of 4-CIBP. The dechlorination percentages of 4-CIBP in the presence of 0.1 mmol/L Co2~, Cuz~ and Niz~ were 66.1%, 66.0% and 64.6% in 48 hr, and then increased to 67.9%, 71.3% and 73.5%, after 96 hr respectively. The dechlorination kinetics of 4-C1BP by the NZVI in all cases followed pseudo-first order model. The results provide a basis for better understanding of the dechlorination mechanisms of PCBs in real environment.

关键词： 4-chlorobiphenyl nanoscale zero-valent iron humic acid metal ions dechlorination

Understanding the electrode reaction process of dechlorination of 2,4-dichlorophenol over Ni/Fe nanoparticles: Effect of pH and 2,4-dichlorophenol concentration

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Journal of Environmental Sciences 2019年第10期31卷 13-20页

作者： Kaiyuan Zheng Yuqiao Song Xu Wang Xin Li Xuhui Mao Dihua Wang School of Resources and Environmental Sciences Wuhan University Wuhan 430079 China Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy Wuhan University Wuhan 430079China

Herein,with the exploitation of iron and nickel electrodes,the 2,4-dichlorophenol(2,4-DCP)dechlorinating processes at the anode and cathode,respectively,were separately studied via various electrochemical techniques(e.g.,Tafel polarization,linear polarization,electrochemical impedance spectroscopy).With this in mind,Ni/Fe nanoparticles were prepared by chemical solution deposition,and utilized to test the dechlorination activities of 2,4-DCP over a bimetallic *** the iron anode,the results showed that higher 2,4-DCP concentration and solution acidity aggravated the corrosion within the *** charge transfer resistance(Rct)values of the iron electrode were 703,473,444,and 437Ω·cm2 for the initial 2,4-DCP concentrations of0,20,50,and 80 mg/L,*** the bulk pH of the 2,4-DCP solution varied from 3.0,5.0to 7.0,the corresponding Rct values were 315,376,and 444Ω·cm2,*** the nickel cathode,the reduction current densities on the electrode at-0.75 V(*** calomel electrode)were 80,106,and 111μA/cm2,for initial 2,4-DCP concentrations of 40,80,and125 mg/*** dechlorination experiments demonstrated that when the initial pH of the solution was 7.0,5.0,and 3.0,the dechlorination percentage of 2,4-DCP by Ni/Fe nanoparticles was 62%,69%,and 74%,respectively,which was in line with the electrochemical experiments.10 wt.%Ni loading into Ni/Fe bimetal was affordable and gave a good dechlorination efficiency of 2,4-DCP,and fortunately the Ni/Fe nanoparticles remained comparatively stable in the dechlorination processes at pH 3.0.

关键词： 2,4-Dichlorophenol(2,4-DCP) dechlorination Corrosion Catalytic hydrogenation Ni/Fe particles

Catalytic dechlorination and detoxification of 1-(2-chlorophenyl) ethanol by Pd/Fe

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 356-362页

作者： G. Daniel SHENG College of Biological and Environmental Engineering Zhejiang University of Technology

1-(2-chlorophenyl) ethanol (CPE) is of health and environmental concern due to its toxicity and its use as an inter-mediate in pharmaceutical manufacturing. The current work deals with the catalytic reductive dechlorination and detoxification of CPE by Pd/Fe bimetal. CPE was effectively dechlorinated to 1-phenyl ethanol (PE) accompanied by the equivalent release of chloride. The extent of CPE dechlorination increased with temperature,Fe dosage and Pd loading. A decrease in solution pH increased CPE dechlorination,resulting presumably from an increase in hydrogen production. Under the specific conditions of 20 g/L Pd/Fe,0.10% Pd (w/w) and initial pH 5-6,the CPE dechlorination was completed within 145 min. The dechlorination fol-lowed a pseudo-first-order kinetics with an activation energy of 56.7 kJ/mol. The results of toxicity testing showed that CPE was very toxic to Chlorella,whereas PE showed little toxicity. The toxicity of the reaction solution declined gradually and the pro-moting effects on Chlorella intensified consequently with the dechlorination process. Thus,the reductive dechlorination of CPE to PE by Pd/Fe was a detoxification process. It may be used to effectively reduce the toxicological effects of CPE-contaminated wastewater,thereby enhancing the performance of subsequent biological processes in wastewater treatment.

关键词： 1-(2-chlorophenyl) ethanol (CPE) Pd/Fe Catalytic reductive dechlorination Detoxification 1-phenyl ethanol (PE)

Kinetics and Mechanism of dechlorination of o-Chlorophenol by Nanoscale Pd/Fe

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Chemical Research in Chinese Universities 2004年第1期20卷 73-76页

作者： WEIJian-jun XUXin-hua LIUYong DepartmentofEnvironmentalEngineering ZhejiangUniversityHangzhou310027P.R.China

Nanoscale Pd/Fe bimetallic particles were synthesized with an efficient method to dechlorinate o-chlorophenol. The nanoscale Pd/Fe particles were determined by transmission electron microscopy and BET specific surface area analysis. Most of the particles are in the size range of 20—100 nm. The BET specific surface area of synthesized nanoscale Pd/Fe particles is 12.4 m 2/g. In contrast, a commercially available fine iron powder(dechlorination reaction takes place on the surface of synthesized nanoscale Pd/Fe bimetallic particles in a pseudo-first order reaction. The surface-area-normalized rate coefficients(k_ SA) are comparable to those reported in the literature for chlorinated ethenes. The observed reaction rate constants(k_ obs) are dominated by the mass fraction of Pd and the mass concentration of the nanoscale Pd/Fe particles.

关键词： Nanoscale Pd/Fe dechlorination o-Chlorophenol Kinetics Mechanism

Catalytic dechlorination of o-chlorophenol by nanoscale Pd/Fe

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Journal of Environmental Sciences 2004年第4期16卷 621-623页

作者： WEIJian-jun XUXin-hua WANGDa-hui DepartmentofEnvironmentalEngineering ZhejiangUniversityHangzhou310027China

Transformation of chlorophenols by nanoscale bimetallic particles represents one of the latest innovative technologies for environmental remediation. Nanoscale Pd/Fe bimetallic particles were synthesized in the laboratory for treatment of o-chlorophenol. Most of the nanoscale particles are in the size range of 20—100 nm. BET specific surface area of the nanoscale Pd/Fe particles is 12.4 m2/g. In comparison, a commercially available Fe powder(dechlorination efficiency is affected by the mass fraction of Pd in the bimetal, nanoscale Pd/Fe mass concentration and mixing intensity.

关键词： nanoscale particles Pd/Fe dechlorination o-chlorophenol

Catalytic reductive dechlorination of p-chlorophenol in water using Ni/Fe nanoscale particles

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Journal of Environmental Sciences 2007年第3期19卷 362-366页

作者： ZHANG Wei-hua QUAN Xie ZHANG Zhuo-yong College of Urban and Environmental Sciences Northeast Normal University Changchun 130024 China School of Environmental and Biological Science and Technology Dalian University of Technology Dalian 116023 China College of Chemistry Inner Mongolia University for the Nationalities Tongliao 028043 China

Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride （NaBH4） with reduction of Ni^2＋ and Fe^2＋ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM （transmission electron microscope）, XRD （X-ray diffractometer）, and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol （p-CP） as a probe agent. Results demonstrated that the nanoscale Ni/Fe could effectively dechlorinate p-CP at relatively low metal to solution ratio of 0.4 g/L （Ni 5 wt%）. The target with initial concentration ofp-CP 0.625 mmol/L was dechlorinted completely in 60 rain under ambient temperature and pressure. Factors affecting dechlorination efficiency, including reaction temperature, pH, Ni loading percentage over Fe, and metal to solution ratio, were investigated. The possible mechanism of dechlorination ofp-CP was proposed and discussed. The pseudo-first- order reaction took place on the surface of the Ni/Fe bimetallic particles, and the activation energy of the dechlorination reaction was determined to be 21.2 kJ/mol at the temperature rang of 287-313 K.

关键词： Ni/Fe bimetal nanoscale particles catalytic reduction p-CP dechlorination