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首页> 外文学位 >Effect of zero valent metals and water miscible solvents on reductive dechlorination of polychlorinated biphenyls.
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Effect of zero valent metals and water miscible solvents on reductive dechlorination of polychlorinated biphenyls.

机译：零价金属和水混溶性溶剂对多氯联苯还原脱氯的影响。

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摘要

The use of polychlorinated biphenyl (PCBs) was discontinued in the 1970's; however, PCB contamination of soils and sediment remains widespread. Many physical, chemical, and biological methods have been developed and evaluated for PCB degradation in the past three decades. Due to PCB's low aqueous solubility, high sorption affinity, recalcitrance and environmental persistence, environmental PCB remediation continues to be economically prohibitive. The use of zero valent iron (ZVI) in dechlorination of PCBs has been reported in several solution systems, but the effectiveness of ZVI to degrade sorbed PCBs has not been addressed in the literature to date. This research focused on developing a zero valent metal (ZVM) system that would be feasible for PCB dechlorination in sediment and soils. PCB dechlorination using nano-scale ZVMs (Fe 0, Zn0, Al0, Fe/Pd, Fe/Ag, Fe/Cu, Fe/Pt) combined with various cosolvents (tetrahydrofuran, ethanol, and acetone) were explored in soil-free and Aroclor 1242 contaminated sediment systems. Fe, Zn, and Al degraded highly chlorinated congeners to less chlorinated congeners. Bimetals, except for Fe/Pt, completely degraded 2,3,4,6-PCB, but at various rates. The dechlorination pathway was affected by the ZVM, not the cosolvent. Nano-scale Fe/0.5% Pd in 30% acetone completely dechlorinated Aroclor 1242 within two minutes in solution, and less than three days in a sediment system. Recoveries of biphenyl and chloride were 90.1 +/- 2.3% and 74.4 +/- 14.5%, respectively, in solution; and 82% and 56%, respectively, in the sediment. Aroclor 1242 removal increased with increasing percentage of Pd and metal to soil ratio. Aqueous chloride and bromide at seawater concentrations reduced removal of Aroclor 1242 with acetone-Fe/Pd system from 89.3% to 18.0% and 9.4%, respectively. In a bench-scale feasibly test simulating a confined storage facilities (CSF) with Aroclor 1242 contaminated sediment, were 82.2 +/- 4.5% and 56.3 +/- 15.2% of PCBs were degraded in 28 days in an aqueous and 30% acetone Fe/0.5% Pd system, respectively. This research identified an environmentally friendly Fe/Pd-cosolvent system that has a high potential to be a feasible alternative technology for in-situ and ex-situ remediation of PCB contaminated soils and sediments.
机译：在1970年代停止使用多氯联苯（PCB）。但是，PCB对土壤和沉积物的污染仍然很普遍。在过去的三十年中，已经开发出许多物理，化学和生物学方法，并对PCB的降解进行了评估。由于PCB的低水溶性，高吸附亲和力，顽固性和对环境的持久性，环境PCB的修复在经济上仍然是禁止的。在几种溶液系统中，已经报道了在PCB的脱氯中使用零价铁（ZVI），但是迄今为止，文献中还没有涉及ZVI降解吸附​​的PCB的有效性。这项研究的重点是开发零价金属（ZVM）系统，该系统可用于沉积物和土壤中的PCB脱氯。在无土壤和无水环境中，探索了使用纳米级ZVM（Fe 0，Zn0，Al0，Fe / Pd，Fe / Ag，Fe / Cu，Fe / Pt）与各种助溶剂（四氢呋喃，乙醇和丙酮）结合进行PCB脱氯的方法。 Aroclor 1242受污染的沉积物系统。铁，锌和铝将高氯化物降解为低氯化物。除Fe / Pt外，双金属完全降解2,3,4,6-PCB，但速率不同。脱氯途径受ZVM而不是助溶剂的影响。在30％丙酮中的纳米级Fe / 0.5％Pd在溶液中的两分钟之内即可完全去除Aroclor 1242的氯，而在沉积系统中则不到三天。溶液中联苯和氯化物的回收率分别为90.1 +/- 2.3％和74.4 +/- 14.5％；分别为82％和56％。随着Pd百分比和金属与土壤比率的增加，Aroclor 1242的去除量也增加。海水浓度下的氯化物和溴化物将丙酮-铁/钯体系对Aroclor 1242的去除率分别从89.3％降至18.0％和9.4％。在模拟Aroclor 1242污染沉积物的密闭存储设施（CSF）的台式规模可行性测试中，在水性和30％丙酮铁中，PCB在28天内降解了82.2 +/- 4.5％和56.3 +/- 15.2％的PCB /0.5% Pd体系。这项研究确定了一种环保的Fe / Pd助溶剂系统，该系统具有很高的潜力，可作为一种可行的替代技术，对PCB污染的土壤和沉积物进行原位和异位修复。

著录项

  • 作者

    Xu, Tianbo.;

  • 作者单位

    Purdue University.;

  • 授予单位 Purdue University.;
  • 学科 Engineering Environmental.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 112 p.
  • 总页数 112
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 环境污染及其防治;
  • 关键词

  • 入库时间 2022-08-17 11:41:33

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