模拟酸雨淋溶下海泡石复合材料对污染土壤镉释放的影响

Effect of Simulated Acid Rain on Releases of Cadmium in a Contaminated Soil Immobilized by Sepiolite-DDTC Compound

为了探究改性海泡石材料对土壤中重金属的钝化效果,采用土柱模拟酸雨淋溶方法研究了天然海泡石(SEP)、二乙基二硫代氨基甲酸钠改性海泡石(SEP-DDTC)、3-巯丙基三乙氧基硅烷改性海泡石(SEP-MPTES)对污染土壤中Cd的淋溶效应。结果表明:p H=4. 0的酸雨淋溶后土壤p H值上升了0. 80～0. 99个单位,淋出液的p H值也明显上升。SEP和SEP-MPTES处理Cd的累积淋溶量分别增加66. 45%和11. 49%,SEP-DDTC处理显著减少45. 98%。SEP-DDTC和SEP-MPTES处理酸雨淋溶后3层土壤有效态Cd含量均低于对照,SEP-DDTC处理比SEP-MPTES处理平均低0. 054 mg·kg-1,表明SEP-DDTC是一种潜在的土壤重金属Cd修复材料。

In order to investigate the immobilization efficiency of heavy metals in soil by functionalized sepiolite materials, the leaching effect of different materials, sepiolite (SEP), sepiolite-diethyldithiocarbamate (SEP-DDTC), sepiolite-3-mercaptopropyltriethoxysilane (SEP-MPTES) on soil polluted by Cd were measured by soil column simulated acid rain leaching. The results show that the pH values of soil increased by 0.80~0. 99 after the leaching of simulated acid rain with pH 4.0, and the pH values of leaching also increased obviously. When the acid rain pH value was 4.0, compared with the CK treatment, the SEP treatment and SEP-MPTES treatment had significant increases in accumulation leaching amount of Cd by 66.45% and 11.49%, respectively. However, the SEP-DDTC treatment had a significant decrease in accumulation leaching amount of Cd by 45.98%. Compared with three layers of soil available cadmium content after simulated acid rain, SEP-DDTC treatment and SEP-MPTES treatment were lower than CK, SEP-DDTC treatment was 0.054 mg·kg^-1 lower than SEP-MPTES treatment in average. It indicates that SEP-DDTC is a potential material for soil heavy metal Cd remediation.