壳聚糖改性生物炭在铅镉复合污染土壤修复中的应用研究

Application of Chitosan Modified Biochar in the Remediation of Lead Cadmium Composite Polluted Soil

为了实现铅镉复合污染土壤的修复,本文采用高温热解方法制备了稻壳生物炭(BR)以及玉米芯生物炭(BM),并采用壳聚糖对生物炭进行改性,研究了不同生物炭对铅镉复合污染土壤的修复效果。结果表明:壳聚糖改性生物炭的比表面积更大,对pH值及土壤电导率的提升效果均远高于未改性生物炭。在修复过程中,土壤中铅、镉的5种形态含量均呈现出残余态>碳酸盐结合态>铁锰结合态>有机结合态>水溶态的趋势,各类生物炭都表现出了对土壤中重金属铅镉的钝化作用,且壳聚糖改性生物炭的钝化效果更优。

In order to achieve the remediation of lead cadmium composite polluted soil,rice husk biochar(BR)and corn cob biochar(BM)were prepared using high-temperature pyrolysis method.Chitosan was used to modify the biochar,and the remediation effect of different biochars on lead cadmium composite polluted soil was studied.The results indicate that chitosan modified biochar has a larger specific surface area and a much higher effect on improving pH and soil conductivity than unmodified biochar.During the remediation process,the five forms of lead and cadmium in the soil showed a trend of residual state>carbonate bound state>iron manganese bound state>organic bound state>water-soluble state.Various types of biochar showed a passivation effect on heavy metal lead and cadmium in the soil,and chitosan modified biochar had a better passivation effect.