巯基-蒙脱石复合材料对不同程度Cd污染农田土壤修复研究

摘要

In order to clarify the effect of thiol-functionalized montmorillonite on reducing Cd uptake by pakchoi(Brassica chinensis) grown in soils contaminated by cadmium in various degrees , pot and field experiments were conducted with different application amounts of thiol-functionalized montmorillonite. Results showed that: (1) Cd in pakchoi decreased by 27.2%, 62.8%, 73.0% and 88.4% compared to the control in the soil containing 3.25 mg·kg-1Cd with the addition dose of the thiol-functionalized montmorillonite respectively at 0.1%, 0.5%, 1% and 2% of the soil. When the addition dose was 1%, Cd in pakchoi was 0.19 mg…kg-1, which is lower than the limited value of 0.2 mg·kg-1set-up by national food safety standard in china (GB2762—2012). Moreover, when the addition doses were 1% and 2%, the water-soluble Cd in soil reduced by 18.2% and 12.4%, and the exchangeable Cd reduced by 23.8% and 28.6%, respectively. (2) Concerning the thiol-functionalized mixed materials, when the addition doses were 0.5%, 1%, 2%, Cd in pakchoi decreased by 41.4%, 69.1%, 80.6% in 3.25 mg·kg-1Cd contaminated soil, and decreased by 47.5%, 72.1%, 85.2% in 1.43 mg·kg-1Cd contaminated soil, and by 18.3%, 52.5%, 79.4% in 0.62 mg·kg-1Cd contaminated soil. Furthermore, the residue effect of the application on the second crop were still significant. Field experiment showed that the materials reduced cadmium accumulation by the pakchoi. Hence, these materials reduced the activity of Cd in the soil and inhibited the uptake and accumulation of Cd by pakchoi. This study provides a new alternative to the remediation of Cd contaminated soil.%为研究巯基-蒙脱石复合材料对重金属镉不同污染水平农田土壤的钝化效果,通过盆栽和大田试验,对不同 Cd 污染水平土壤中施加巯基-蒙脱石复合材料及巯基混合修复材料,并种植小白菜(Brassica chinensis).结果表明,(1)向镉高污染水平(Cd 3.25 mg·kg-1)土壤施加0.1%、0.5%、1%、2%巯基-蒙脱石复合材料后,小白菜Cd含量分别降低27.2%、62.8%、73.0%和88.4%,且当添加量为1%时,小白菜Cd含量为0.19 mg·kg-1,低于《食品安全国家标准》(GB2762￣2012)中的限量值0.2 mg…kg-1;同时当添加量为1%、2%时,土壤Cd水溶态含量分别比空白对照降低18.2%、12.4%,Cd离子交换态含量分别比空白对照降低23.8%、28.6%.(2)按0.5%、1%、2%添加巯基混合修复材料后,镉高污染水平土壤中小白菜Cd含量分别降低41.4%、69.1%、80.6%;镉中污染水平(Cd 1.43 mg·kg-1)土壤中小白菜Cd含量分别降低47.5%、72.1%、85.2%;镉低污染水平(Cd 0.62 mg·kg-1)土壤中小白菜Cd含量分别降低18.3%、52.5%、79.4%.后效试验表明,在种植第二季小白菜时,修复材料的钝化效果仍然相当显著.田间试验表明,添加修复材料显著降低了小白菜对Cd的累积.由此说明,钝化材料降低了土壤中Cd的活性,有效地固定了土壤中的Cd,抑制了小白菜对镉的吸收.该研究可为不同程度Cd污染农田钝化修复技术提供新的途径.