采用巯基捕收剂稳定化处理垃圾焚烧飞灰中的重金属

研究了3种巯基捕收剂，二乙基二硫代氨基甲酸钠（乙硫氮）、乙基黄原酸钾（乙基黄药）和二丁基二硫代磷酰铵（丁铵黑药），对垃圾焚烧飞灰中重金属的稳定化效果.3种巯基捕收剂的用量均为62.5　μmol·g^-1飞灰.扫描电镜观察发现，飞灰经稳定化处理后，巯基捕收剂均匀地覆盖于飞灰晶体表面，使矿物晶体棱角变得模糊.利用酸浸提程序（TCLP法）和水浸提程序（水平振荡法）评价飞灰中重金属Cu、Pb、Cd、Cr和Zn的浸出毒性.在0.1 mol·L^-1醋酸浸提条件下，与Na₂S相比，巯基捕收剂对Cu和Pb的稳定化效果较好，其中乙硫氮对Cu的稳定化比率接近100%，丁铵黑药对Pb的稳定化比率达到69.2%；在水浸提条件下，乙硫氮、乙基黄药和丁铵黑药对5种重金属的稳定化比率分别为72.6%、73.5%和76.8%，显著高于Na₂S处理（52.4%）. 3种巯基捕收剂对5种重金属亲和力的强弱顺序大致为Cu＞Pb＞Cr＞Cd＞Zn，并且超过60%的巯基捕收剂与酸可浸提重金属离子发生了螯合沉淀反应.重金属-巯基捕收剂絮凝物在中性和碱性条件下（pH>6）比较稳定，在酸性条件下（pH<6）可发生部分溶解.为获得较好的重金属稳定化效果，维持稳定化飞灰的高酸缓冲容量十分重要.

Stabilization of Heavy Metals in Municipal Solid Waste Incineration Fly Ash with the Thiol Collectors

A bacterium capable of utilizing 1,2,4-trichlorobenzene as sole carbon source was isolated from the polluted soil sample. This baterium was identified as Pseudomonas nitroreducens according to its physiological & biochemical analysis and its 16S rDNA sequence(GenBank Accession No. EF107515). When the initial concentration of 1,2,4-TCB is 400mg/L, J5-1 can achieve a maximum degradation rate of 90%. When the initial concentration of 1,2,4-TCB is 20mg/L, the effect of degradation is the best. Degradation of 1,2,4-TCB by strain J5-1 obeys the first order dynamics. The total gene Chlorocatechol 1,2-dioxygenase were cloned from genomic DNA of J5-1.