含硫材料对中碱性农田土壤镉的钝化效果

Study on the Effect of Sulfur Materials on Immobilization of Cadmium in Contaminated Alkaline Farmland Soils

通过模拟实验探讨含硫材料〔硫化钙(CaS)、聚合二硫代氨基甲酸钠(DTCR)和2,4,6-三巯基均三嗪三钠(TMT)〕对中碱性农田土壤中镉的钝化效果。结果显示,相同试验条件下,在2种麦田土壤(来自河南新乡和济源)中,3种钝化剂对DTPA有效态镉降低效率的大小顺序均为TMT55(纯度w为55%)>DTCR>CaS。在有效态镉含量为1.56 mg·kg^-1的新乡土壤中添加w=0.10%的CaS、DTCR和TMT55,稳定30 d后有效态镉含量分别比对照降低21.15%、48.71%和41.69%。在有效态镉含量为0.97 mg·kg^-1的济源土壤中添加w=0.10%的CaS、DTCR和TMT55,稳定30 d后有效态镉含量分别比对照降低10.42%、40.43%和40.70%。与其他材料相比,DTCR和TMT55具有低剂量和高效率的优点,是潜在的中碱性农田土壤重金属镉修复材料。

Immobilization experiments were performed to investigate the immobilization effect of the sulfur materials[calcium sulphide(CaS),sodium dithiocarbamate(DTCR)and 2,4,6-trimercaptotriazine(TMT55)]on reducing available cadmium(Cd)in contaminated alkaline farmland soils.The results show that the order of the DTPA available cadmium reduction efficiency of the three passivants in the two soils(from Xinxiang and Jiyuan in Henan Province)was TMT55>DTCR>CaS,under the same conditions.In Xinxiang Cd contaminated soil(DTPA-Cd 1.56 mg·kg-1)after adding 0.10%(mass fraction)CaS,DTCR and TMT55,the available Cd content of the soil reduced by 21.15%,48.71%and 41.69%after 30 days,respectively,compared with the controlled experiment.In Jiyuan Cd contaminated soil(DTPA-Cd 0.97 mg·kg-1)after adding 0.10%(mass fraction)CaS,DTCR and TMT55,the available Cd content of the soil reduced by 10.42%,40.43%and 40.70%after 30 days,respectively,compared with the controlled experiment.DTCR and TMT55 had the advantages of low dosage and high efficiency compared with other materials.It indicates that DTCR and TMT55 are potential materials for remediation of Cd-contaminated alkaline farmland soil.