红壤对污染土壤中砷的修复性能研究

为探寻农田砷污染治理的绿色修复剂,以源自自然环境的红壤作为绿色修复剂材料,首先通过静态吸附实验研究红壤对水溶液中砷的吸附能力,其次通过向砷污染农田土壤中添加红壤,探讨红壤对污染土壤中砷的形态及其生物有效性的影响. 吸附实验结果表明,红壤对溶液中砷的吸附等温过程更符合Freundlich方程; 添加红壤可有效降低土壤中弱酸态砷和水溶态砷含量占百分比,但可氧化态砷含量占百分比显著增加; 弱酸态砷含量与红壤添加量呈显著负相关关系(R²_0.05=0.991). 此外,添加红壤后,污染土壤纯水和碳酸氢钠提取液中砷含量及污染土壤纯水提取液对发光菌的急性毒性显著降低,说明添加红壤可降低污染土壤中砷的生物有效性.

Remediation Effects of Arsenic-Contaminated Soil by Red Soil

To seek a green amendment for arsenic(As)contaminated agricultural soil,red soil is used as green amendment for As in this study,which comes from the natural environment. Firstly,static adsorption experiment is performed to investigate the adsorption characteristics of As on red soil. Then the effects of the As availability and changes of As fractionations are investigated by adding red soil into the contaminated agricultural soils. The results of static adsorption experiment indicate that Freundlich adsorption isotherm model can better describe the isotherm process of adsorption. The percentage of exchangeable As and water-soluble As decreases,while the percentage of oxidizable As increases by adding red soil. The percentage of exchangeable As is negatively correlated with the amount of red soil(R²_0.05=0.991). Both extractable-As(with water or NaHCO₃)and the acute toxicity to luminescent bacteria are decreased significantly after the addition of red soil,suggesting that the addition of red soil can reduce the bioavailability of As in the contaminated soil.