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

1-（2-chlorophenyl） ethanol （CPE） is of health and environmental concern due to its toxicity and its use as an intermediate 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 l-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 rain. The dechlorination followed 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 promoting 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.     

离子交换树脂除氯法在来宾华锡冶炼有限公司的应用

文章主要介绍了离子交换树脂除氯在来宾华锡冶炼有限公司的生产概况,工艺技术条件以及除氯效果和存在的问题。     

Simulation of reductive dechlorination processes in a lab-scale anaerobic biobarrier with enriched TCP dechlorinating consortium

In order to design and predict the dechlorination processes for remediating the halogenated aromatic compounds in the biobarrier system applied in situ,an anaerobic continuous-flow column was set up with the introduction of an enriched 2,4,6-trichlorophenol(TCP) reductive dechlorinating consortium.The fates of TCP and its metabolites were simulated according to the first-order sequential dechlorination kinetic model.The enriched TCP anaerobic dechlorinating consortium dechlorinated 100 μmol/L TCP to 4-chlorophenol(4-CP) via 2,4-dichlorophenol(DCP) in 10 d.The consortium was predominated with the phylum of Firmicutes and Bacteroidetes,based on the PCRdenaturing gradient gel electrophoresis(DGGE) analysis.After the consortium was applied to the column,the experimental data in the steady state were fitted by the least square method,and the first-order dechlorination kinetic constants from TCP to 2,4-DCP,from 2,4-DCP to 4-CP and from 4-CP to phenol,were 1.58 d-1,2.23 d-1 and 0.206 d-1,respectively.According to the fitting results,the required biobarrier width for the complete remediation of TCP,2,4DCP and 4-CP were 126 cm,130 cm and 689 cm,respectively.The dechlorination/degradation of 4-CP must be increased when the technology is applied to the real site.     

水中2,4-二氯苯酚和五氯苯酚电子束辐射降解的研究

用电子束辐射降解水中的2, 4-二氯苯酚(2, 4-DCP)和五氯苯酚(PCP), 研究辐照剂量对溶液初始质量浓度各为50 mg/L的2种氯代苯酚辐射降解和去除有机氯的影响. 同时研究了溶液不同的初始质量浓度、pH值和去氧状态等条件对辐射降解的影响. HPLC的测试结果表明: 随着辐照剂量的增加,氯代苯酚的降解率增加, 溶液中的氯离子增加, 但辐照后溶液中仍有2, 4-DCP和PCP的残余物. 试验结果表明: 有机氯辐射降解的速度要比无机氯生成的速度快得多; 溶液的去氧也能加快氯代苯酚的降解; 在酸性到中性条件下比碱性条件下更利于有机氯裂解.     

铜渣法除电解锌溶液中氯的工艺研究

采用铜渣法除去电解锌溶液中的氯,并通过正交实验考察了影响铜渣法除氯的各种因素。实验结果表明,铜渣法除氯的最佳工艺条件为:铜渣中铜与Cl-的物质的量的比值为1.25∶1,CuSO4.5H2O与Cl-的物质的量之比为0.6∶1,反应温度为7 0℃,反应时间为3 h,初次除氯率达到85%以上。通过二次除氯可使氯离子含量降低至100 mg/L以下。     

Rapid dechlorination of chlorinated organic compounds by nickel/iron bimetallic system in water

Detoxification of chlorinated organic compounds via reaction with nickel/iron powder was implemented in aqueous solution. Compared to iron, nickel/iron bimetallic powder had higher hydrodechlorination activities for both atrazine (ATR) and p-chlorophenol (pCP); nickel/iron (2.96%, w/w) was shown to have the largest specific surface area and the optimum proportion for the dechlorination of both ATR and pCP. Electrochemical measurements showed that the adsorbed hydrogen atom on the nickel must have been the dominant reductive agent for the dechlorination of both ATR andpCP in this system.     

连二亚硫酸钠对淹水土壤中p,p'-DDT 脱氯过程的影响及机理研究

在淹水培养条件下(土/水=2 g/40 mL),研究连二亚硫酸钠(200 mmol/L Na₂S₂O₄)对p,p'-DDT在自然土和Na₂S₂O₄还原土壤中降解历程的影响及机理. 在自然土和还原土中添加Na₂S₂O₄促进p,p'-DDT降解,2 d降解率分别为73%和79%,随后降解缓慢. p,p'-DDT在土壤中降解为p,p'-DDD和p,p'-DDE. p,p'-DDT主要被Na₂S₂O₄降解,Na₂S₂O₄还原土壤产生的Fe²⁺也有贡献. Na₂S₂O₄与Fe²⁺体系对修复DDTs污染土壤有应用前景.     

一种催化氢转移脱羰基化合物α-氯原子的方法

开发了一种催化氢转移脱羰基α-氯原子的方法。该方法以甲酸铵做氢供体,Pd/C为催化剂,室温条件,质子性溶剂。其最大优点为条件温和,后处理简便,反应时间短,收率高。