鸽粪基生物炭对土壤重金属形态的影响

基于鸽粪基生物炭的优良特性,进行模拟重金属污染土壤修复试验,研究了其对Cu、Zn、Pb、Cd的作用效果及土壤中赋存形态转化的影响.结果表明:鸽粪基生物炭中的CO_3^2-及OH-可与溶液中的Pb反应产生Pb的碳酸盐和氢氧化物沉淀;在重金属复合污染土壤中添加生物炭后,生物有效性最强的可交换态Cu、Zn、Pb、Cd含量分别降低98.48%、61.79%、89.15%和32.76%.生物炭中的灰分使土壤pH值显著升高(2.5~3.13),从而增加了碳酸盐结合态含量;而土壤有机质含量的升高(37.75%~178.43%)直接导致有机结合态含量增加;和500℃生物炭相比,400℃生物炭有机质含量更高,灰分含量更低.本研究的结果可以为鸽粪基生物炭在重金属复合污染土壤修复中的应用提供一定的理论基础,也为鸽粪固废处理开拓了新的思路.

Effects of Pigeon Manure-Based Biochar on Fractionation in Heavy Metal Contaminated Soils

In view of the superior physical and chemical characteristics of pigeon manure-based biochar,a simulation system for the remediation of heavy metal-contaminated soil was designed and developed.The effects of the system on Cu,Zn,Pb,Cd and the transformation of existing forms in soil were studied.The results show that the reactions of CO32-and OH-in pigeon manure-based biochar with Pb resulted in the precipitation of carbonate and hydroxide of Pb.Exchangeable states with the strongest bioavailability of Cu,Zn,Pb and Cd decreased by 98.48%,61.79%,89.15%and 32.76%,respectively,after adding biochar to soil.Soil pH values increased by 2.5—3.13 units owing to ash in biochar,which generated the increase of carbonate binding state,while the increase of organic matter content by 37.75%—178.43%directly led to the increase of organic binding state.Compared with the biochar producted at 500℃,the biochar producted at 400℃had higher organic matter content but lower ash content.The results in this paper can provide a theoretical basis for the application of pigeon manure-based biochar in the remediation of heavy metal-contaminated soils and new ideas for pigeon manure solid waste treatment.