不同硒化修复剂对稻田汞污染修复效果研究

以亚硒酸钠、蒙脱土等作为材料，对蒙脱土进行硒化改性，将硒负载在经过改性的蒙脱土上制备出汞的钝化剂以降低汞和甲基汞（MeHg）在稻米中的富集.将硒化修复剂与污染土壤混合进行浸泡土试验和盆栽试验，分析土壤和稻米中THg和MeHg，探讨不同硒化修复剂对污染土壤中汞的阻控修复效果，并筛选出最佳修复剂.结果表明，4种修复剂均对污染土壤中汞有明显的钝化阻控作用，可显著降低土壤中可交换态汞和甲基汞，降低稻米中THg和MeHg含量.蒙脱土通过不同方式硒化改性后，使蒙脱土结构性能优化，吸附容量增加，并能使硒稳固在蒙脱土上，达到更好的钝化修复效果.硒化壳聚糖改性蒙脱土、亚硒酸钠改性蒙脱土、硒化纤维素改性蒙脱土、硒粉改性蒙脱土4种修复剂稻米THg的降低率依次为81.86%、79.74%、65.69%、61.78%，MeHg降低率依次为89.62%、83.91%、72.93%、63.01%.相比较而言，亚硒酸钠改性蒙脱土修复效果稍低于硒化壳聚糖改性蒙脱土，但其改性方法简单，成本低，更有利于修复剂的推广应用.

Effect of different selenization remediation agents on remediation of mercury pollution in paddyfields

Modification of montmorillonite with selenium was carried out with sodium selenite, montmorillonite and other materials, and the passivation agent of mercury was prepared by combining selenium with modified montmorillonite, so as to reduce the enrichment of mercury and methyl mercury in rice. In this paper, selenide repairing agent was mixed with the contaminated soil for soaking soil test and pot experiment, the THg and MeHg in soil and rice were analyzed, effect of different selenide repairing agents on the control of mercury in polluted soil was discussed, and the best repair agent was selected.The results showed that all four kinds of repairing agents had obvious passivation and control effect on mercury in contaminated soil, which could significantly reduce the exchangeable mercury and methylmercury in soil and reduce the content of THg and MeHg in rice. After the montmorillonoid was modified by selenium in different ways, the structural energy of montmorillonite was optimized, the adsorption capacity was increased, and the selenium can be stabilized on montmorillonite to achieve better passivation effect. The reduction rate of the modified montmorillonite with selenide chitosan, the modified montmorillonite with sodium selenite, the modified montmorillonite with selenide cellulose and the modified montmorillonite, with selenium powder to rice THg was 81.86%, 79.74%, 65.69% and 61.78%, respectively, and the reduction rate of these repairing agents to rice MeHg was 89.62%, 83.91%, 72.93% and 63.01%, respectively. Comparatively speaking, the remedial effect of the modified montmorillonite with sodium selenite was slightly lower than that of the modified montmorillonite with selenide chitosan, but its modification method is simple and low cost, which is more favorable to the popularization and application of repairing agent.