改性蒙脱土对稻田土壤甲基汞的阻控修复

采用3-巯丙基三甲氧基硅烷和壳聚糖对蒙脱土进行改性,利用XRD技术对改性蒙脱土进行表征,并通过室内模拟试验,探讨在不同的水分条件下,巯基蒙脱土和壳聚糖蒙脱土对甲基汞污染土壤的阻控修复效果.XRD分析结果显示,巯基和壳聚糖都成功负载于蒙脱土上.模拟试验结果表明,在甲基汞污染土壤中添加修复材料后,对土壤甲基汞均产生了较好的阻控修复效果.对比空白对照,在淹水条件下,土壤中甲基汞含量分别降低了82. 10%(巯基蒙脱土)和45. 20%(壳聚糖蒙脱土);在干湿交替条件下,土壤中甲基汞含量分别降低了66. 70%(巯基蒙脱土)和49. 79%(壳聚糖蒙脱土);在干旱条件下,土壤中甲基汞含量降低了44. 66%(巯基蒙脱土),添加壳聚糖蒙脱土4周后,土壤甲基汞含量降低了54. 37%.相比单加改性蒙脱土,联合添加改性蒙脱土和石灰处理后其修复效果没有明显提升.

Inhibition and Remediation of Methylmercury Contaminated Soil by Use of Modified Montmorillonite

Montmorillonite was modified by 3-mercaptopyl trimethoxysilane and chitosan. The modified montmorillonite was characterized by XRD technology. The effects of thiol montmorillonite and chitosan montmorillonite on the inhibition and remediation of methylmercury contaminated soil under different water conditions were studied using laboratory simulation. XRD results showed that both thiol and chitosan were successfully loaded on the montmorillonite. The results of simulation tests showed that the addition of the remediation material to soil contaminated with methylmercury produced a better remediation effect. Compared with the blank control, the content of methylmercury in the soil was reduced by 82.10% (thiol montmorillonite) and 45.20% (chitosan montmorillonite), respectively, in the flooded condition. Under dry/wet alternation, the content of methyl mercury in soil decreased by 66.70% (thiol montmorillonite) and 49.79% (chitosan montmorillonite), respectively. Under drought conditions, the content of methylmercury in soil decreased by 44.66% (thiol montmorillonite), and the concentration of methylmercury in soil decreased by 54.37% after adding chitosan montmorillonite for 4 weeks. Compared with single modified montmorillonite, the repair effect of combined modified montmorillonite and lime treatment was not improved significantly.