高分子聚合物与钝化剂复配对汞污染土壤钝化修复研究

PASSIVATION AND REMEDIATION OF MERCURY CONTAMINATED SOIL BY POLYMER AND PASSIVATOR

采用盆栽试验方法,研究了添加1种耐酸性较强的高分子聚合物与传统的有机或无机类钝化剂复配来钝化土壤重金属汞,并探讨其对土壤理化特性、植物生长发育、土壤汞形态以及酶活性等的影响。结果表明:与对照(CK)相比,添加不同钝化剂均能有效改善汞污染土壤理化状况和土壤微环境,促进植物生长。不同钝化剂处理均显著降低了土壤有效态汞的比例,土壤水溶态、可交换态汞比例分别较CK降低了106%~315%、12.61%~34.60%;与单一钝化剂相比,添加高分子聚合物的钝化剂能更有效吸附、固定土壤中的汞,并降低土壤重金属汞的生物有效性;生物炭-聚丙烯酰胺(BI-PAM)处理对土壤有机质含量和pH增加最为明显,且对土壤重金属汞的钝化效果最好(水溶态汞、可交换态汞和Fe-Mn氧化物结合态汞占总汞比例最小,分别为1.05%、12.14%、12.72%,而强有机结合态汞和残渣态汞比例最高,分别为15.86%和58.23%),能促进增产且减少白菜叶片对汞的吸收富集。根据试验结果,针对汞污染酸性土壤,建议施用生物炭与聚丙烯酰胺复配而成的钝化剂。

A pot experiment was carried out to study the effects of adding high polymer with strong acid resistance and traditional organic or inorganic passivator to passivate the heavy metal mercury in soil, and to explore its effect on the physical and chemical properties of soil, the growth of plants, the form of mercury in soil and the activity of enzyme. The results showed that: compared with CK, adding different passivators could effectively improve the physical and chemical conditions of mercury contaminated soil and soil microenvironment, and promote plant growth. Compared with CK, the proportion of available mercury in soil was significantly reduced by different passivators, and the ratio of water-soluble and exchangeable mercury in soil decreased by 106%~315% and 12.61%~34.60%, respectively. Compared with single passivator, the bonding passivator with polymer could effectively adsorb and fix mercury, and reduce the bioavailability of heavy metal mercury in soil. The biochar polyacrylamide(BI-PAM)treatment had the best effect on soil organic matter content and pH, and the best passivation effect on heavy metal mercury in soil(water soluble mercury, exchangeable mercury and Fe-Mn oxide bound mercury accounted for the smallest proportion of total mercury, which were 1.05%, 12.14% and 12.72% respectively, while strong organic bound mercury and residual mercury accounted for the highest proportion, which were 15.86% and 58.23% respectively), which could promote the yield and reduce the absorption and enrichment of mercury in cabbage leaves. According to the experimental results, the bonding passivator of biochar and polyacrylamide was recommended in application in acid soil polluted by mercury.