Chloro-Organic Degradation by Nanosized Metallic Systems

开发利用氧化和还原途径对危险有机物进行有效脱氯的技术需要多种技术。氯化有机物包括氯乙烯(如脱脂溶剂、三氯乙烯、三氯乙烯)、氯酚、多氯联苯(RGB)等。许多氯化有机物即使在低浓度下也是有毒的，并对环境产生累积的有害影响。这项建议的总体目标是开发基于铁的氧化型(具有Fe(11)螯合物)和还原(零价铁与掺杂，例如，Ni，Pd)平台，适用于选定的氯-有机解毒(多氯联苯和三氯乙烯)的高效修复策略。我们最近的研究工作表明，基于螯合物修饰的羟基自由基氧化反应和 用于还原脱氯的纳米级零价金属。对这些反应系统的基本了解对于包括补救在内的可持续利用至关重要。对于氧化系统，拟议的研究将检查酶在原位产生过氧化氢，将多螯合物(如聚丙烯酸)固定在惰性粒子上，以控制形成羟基自由基所需的Fe(11)的释放，以及控制脱氯速度。还原平台将研究使用化学还原剂(如硼氢化物)和使用导电聚合物中的电化学技术的一种新的颗粒形成方法来合成纳米Fe/Ni和Fe/Pd双金属体系。建议数 研究将需要几项研究，涉及材料的开发、试剂固定化技术、表面形态的量化、用于确定反应速率和碳平衡闭合的母体化合物和中间体分析以及用于修复需要的反应动力学参数。由于危险废物和超级基金场地往往含有有机物混合物，同时开发氧化和还原补救技术应提供更灵活和更易处理的方法。

Versatile technologies are required for the development of effective dechlorination techniques of hazardous organics utilizing both oxidative and reductive pathways. Chlorinated organics range from chloroethylenes (such as the degreasing solvent, trichloroethylene, TCE), chlorophenols, polychlorinated biphenyls (RGBs), etc. Many chlorinated organics are toxic even at low concentrations, and exert a cumulative, deleterious effect on the environment. The overall objective of this proposal is to develop iron-based oxidative (with Fe(ll) chelates) and reductive (zero valent Fe with dopants such as, Ni, Pd) platforms suitable for highly effective remediation strategies for selected chloro-organic detoxification (PCB's and TCE). Our recent research work has shown the benefits of chelate-modified hydroxyl radical-based oxidative reaction and nanosized zero valent metals for reductive dechlorination. The fundamental understanding of these reactive systems is critical for sustainable use involving remediation. For the oxidative systems, the proposed research will examine in-situ generation of hydrogen peroxide by enzymes, immobilization of polychelates (such as poly-acrylic acid) on inert particles for controlled release of Fe(ll), which is needed for hydroxyl radical formation, and control of dechlorination rates. The reductive platform will examine synthesis of nanosized Fe/Ni and Fe/Pd bimetallic systems using chemical reductants (such as borohydride) and by a novel particle formation method using electrochemical technique within conducting polymers. The proposed research will require several studies involving development of materials, reagent immobilization techniques, quantification of surface morphology, parent compound and intermediates analysis for establishing reaction rates and carbon balance closure, and reaction kinetic parameters for remediation needs. Since hazardous waste and Superfund sites often contain mixture of organics the simultaneous development of both oxidative and reductive remediation techniques should provide more flexibility and tractable approaches.