活性炭固定沉积物中HCHs和DDTs的研究

Sequestration of HCHs and DDTs in contaminated sediment by activated carbon

在对沉积物的修复技术中,原位覆盖技术能够降低污染物向水体的释放,降低污染物对底栖生物和水生生物的生物可利用性,以及能够减少污染物向下游的迁移。在本研究中,将活性炭添加到受HCHs、DDTs污染的沉积物中,考察了活性炭剂量、粒径以及活性炭与沉积物接触的方式对HCHs、DDTs水相平衡浓度的影响,及对半渗透膜（SPMD）吸收HCHs、DDTs的影响。结果表明,当加入的活性炭为沉积物TOC含量的4倍（7.6%）时,活性炭与沉积物接触150 d,HCHs、DDTs的水相浓度分别减少了99.76%、97.68%;SPMDs对HCHs、DDTs的吸收量减少了97.19%、100%。将3种不同粒径的活性炭加入到受污染的沉积物中,结果显示,采用0.075~0.27 mm的活性炭处理28 d时,HCHs、DDTs的水相浓度分别减少99.63%、96.33%,SPMDs吸收的HCHs、DDTs的量降低了91.52%、98.76%。当活性炭与沉积物的接触方式不同时,对活性炭和沉积物进行持续的振荡能更有效地降低HCHs、DDTs的水相浓度以及SPMDs吸收的HCHs、DDTs的量。我们的研究证实,向受到HCHs、DDTs污染的沉积物中投加活性炭,是一种有效的原位修复方法。

In-situ capping is an important technology for the remediation of contaminated sediment.The benefits of in-situ capping are the reduction of contaminant water-column concentrations and therefore reduced bioavailability to benthic and aquatic organisms,as well as the minimization of downstream migration.In this study,activated carbon was mixed in HCH-and DDT-contaminated sediment for 28 days,60 days and 150 days.The effects of varying the activated carbon dose,particle size and contacting ways were tested in reducing the aqueous equilibrium HCHs and DDTs concentrations and in reducing the uptake by semi-permeable membrane devices（SPMD）.Sediment treated with 7.6% activated carbon for 150 days showed 99.76% and 97.68% reductions in aqueous equilibrium HCHs and DDTs concentrations,97.19% and 100% reductions in HCHs and DDTs uptake by SPMDs,respectively.Three different particle sizes of activated carbon were tested in the study.When 0.075~0.27 mm of activated carbon were mixed in sediment with a contact period of 28 days,the aqueous equilibrium HCHs and DDTs concentrations were reduced by 99.63% and 96.33% and the uptakes by SPMDs were reduced by 91.52% and 98.76%,respectively.The effectiveness of activated carbon contacting sediment by continuously shaking is greater as compared to by setting after mixing.The results of the study demonstrated the potential usefulness of activated carbon amendment as an in-situ remedial technology for contaminated sediment.