腐殖酸-海泡石复合钝化剂的制备及其对Cd污染土壤的修复

对海泡石进行热改性,以腐殖酸和海泡石为原料,制备了腐殖酸-海泡石复合钝化剂。采用BCR形态分析法研究了复合钝化剂对镉污染土壤的钝化效果。结果表明,制备复合钝化剂的最佳工艺条件为：腐殖酸与海泡石质量比2∶1,氢氧化钠质量浓度0.04 g/mL,热反应时间40 min,热反应温度80 ℃。复合钝化剂的最佳添加量为7%（w）,培养3 d后,钝化效率达46.87%,土壤pH升高至7.02,活稳比降低为0.65,土壤中镉的释放风险显著降低。复合钝化剂修复镉污染土壤时,会促使活性态镉向稳定态镉转化,使镉在土壤中的稳定性提高。

Preparation of humic acid-sepiolite composite passivator and its remediation effect on Cd contaminated soil

The humicacid-sepiolite composite passivator was prepared by thermal modificationusinghumic acid and sepiolite as raw materials. The passivation effect of compound passivator on cadmium contaminated soilwas studied byBCR morphological analysismethod. The results show that the optimum conditions forpreparation of the compositepassivator are as followsmass ratio of humic acid to sepiolite 2∶1,mass concentration of sodium hydroxide 0.04 g/ml,thermal reaction time 40 min,andthermal reaction temperature 80 ℃. The optimal dosage of the compositepassivatoris 7%（w）. After 3 d of culture,the passivation efficiency is 46.87%,the soil pH increasesto 7.02,the ratio of activity to stability decreasesto 0.65,and the risk of cadmium release in soil decreasessignificantly. When the cadmium polluted soilis treatedusingthe compositepassivator,the transformation of active cadmium to stable cadmiumis promoted and the stability of cadmium in the soilis improved.