摘要
有色金属矿山开采是重金属的主要来源之一,而矿山开采引起的下游土壤重金属污染以致危及人群身体健康的事件时有报道,如何修复重金属复合污染土壤已成为研究的热点。以某金属尾矿库下游重金属污染土壤为研究对象,采用EDTA、茶皂素和二者的混剂作为淋洗剂,研究了两种淋洗剂及其混剂对土壤中铅、锌各形态的解吸效果。结果表明,(1)研究区土壤铅质量分数为1 035 mg·kg-1,锌质量分数为837 mg·kg-1,远远超过土壤环境质量标准限值;淋洗前,土壤重金属形态质量分数分别为:土壤中重金属的残渣态最高,其次分别为铁锰结合态、碳酸盐结合态、有机结合态与可交换态。铅、锌有效态占质量分数的比例分别为58.9%和49.5%。(2)EDTA对铅和锌形态的解吸效果表现为:可交换态>铁锰氧化物结合态>碳酸盐结合态>有机结合态>残渣态,茶皂素对锌的解吸效果与EDTA的一致;茶皂素对铅与混合剂对铅和锌解吸效果一致,表现为可交换态>碳酸盐结合态>铁锰氧化物结合态>有机结合态>残渣态,说明EDTA和茶皂素对铅锌的作用机制可能存在很大差别。(3)从各种形态重金属去除效果来看,可交换态和碳酸盐结合态因其易释放性有很好的解吸效果,残渣态在各形态中最稳定,较难被解吸;EDTA、茶皂素及其混剂对铁锰氧化物结合态的解吸效果远大于有机态。
The effect of EDTA, saponin and mixed releasing reagent to removal Pb and Zn in downstream soils of the tailings in dabaoshan mine were investigated Soil. The resulting was following: (1) The concentrations of Pb and Zn were 1035.42 mg·kg-1 and 837.32 mg·kg-1 separately. The residual fraction was exists mainly of heavy metals in soil, followed by iron and manganese bound, carbonate, organic matter and exchangeable. The proportion of the total amount of heavy metals of lead and zinc effective state was 58.9% and 49.5% respectively. It indicated that leaching of heavy metals in soil removal is an effective technique. (2) The desorption performance on various forms of EDTA for lead and zinc, tea saponin for zinc showed that exchangeable > Fe-Mn oxides > carbonate fraction > organic fraction > residual fraction. The desorption performance on various forms of tea saponin for lead and zinc, mixture for lead and zinc showed that exchangeable > carbonate fraction > Fe-Mn oxides > organic fraction > residual fraction. It showed other forms > organic fraction > residual overall. (3) There were good desorption performance of exchangeable and carbonate fraction due to release easily. The residual fraction was difficult to desorb because of stable. And the performance of EDTA, saponin and mixed releasing for Fe-Mn oxides was much better than organic fraction.
出处
《生态环境学报》
CSCD
北大核心
2015年第8期1394-1398,共5页
Ecology and Environmental Sciences
基金
广东省教育部产学研结合项目(2012B091000152)
广东省科技计划项目(2013B020307011)
