生物质灰复配磷酸盐对污染土壤铜铅钝化的影响

Effects of Biomass Ash Combined with Phosphate on the Immobilization of Copper and Lead in Contaminated Soil

【目的】生物质灰(BA)的多孔结构和表面丰富的含氧官能团使其对重金属具有较强的吸附能力,同时磷基材料能够与重金属离子形成较为稳定的沉淀,从而降低其活性。本研究通过将生物质灰与含磷材料配施于重金属污染土壤中,以期进一步提高生物质灰对重金属的钝化效果。【方法】将生物质灰与磷酸二氢钾(KH_(2)PO_(4))以10:4复配,按照土壤质量0.2~0.6%的比例添加复配材料,研究其对污染土壤中铜(Cu)和铅(Pb)的钝化效果。【结果】生物质灰复配磷酸盐(BAP)较单一生物质灰更显著的提高了土壤pH。经过45 d的培养,BA与BAP处理土壤有效态Cu较对照最高分别降低57.0%和93.0%,有效态Pb降低64.6%和99.6%,同时土壤有效磷含量提高388%。BAP较BA更有效地促进Cu由活性态向中间形态转化,促进Pb由活性态向中间形态和稳定态转化。【结论】生物质灰复配磷酸盐有助于提高生物质灰对土壤Cu和Pb的钝化效果,可以用于重金属污染土壤的钝化修复。

[Objective]Biomass ash(BA)can effectively adsorb heavy metals since it has amounts of micro-pores and functional groups.Meanwhile,the phosphorus-based materials could decrease the availability of heavy metals through the formation of metal-phosphate precipitation.In this study,phosphorus-containing materials were combined with biomass ash so as to further improve the immobilization effect of heavy metals in soil.[Method]The immobilization effects of Cu and Pb in contaminated soil were studied after the application of biomass ash combined with potassium dihydrogen phosphate(KH_(2)PO_(4))with a 10:4 ratio under the dosages of 0.2~0.6%.[Result]Soil pH in biomass ash combined with phosphate(BAP)treatments was effectively increased than that of single biomass ash(BA)treatments.After 45 d of incubation,the available Cu in the BA and BAP treatments decreased by 57.0%and 93.0%,respectively,and the available Pb decreased by 64.6%and 99.6%,compared with the control.While the soil available phosphorus was increased by 388%than the control.Compared with the BA treatment,the combination treatments were more effective to transform the Cu from active fraction to moderately active fraction,and from active fraction to moderate active and stable fractions for Pb.[Conclusion]Phosphate was facilitated to the immobilization of soil Cu and Pb by biomass ash,and the phosphate combined with biomass ash could be used to immobilize the heavy metals in soils.