改性壳聚糖对多重金属污染土壤酸雨淋溶特征  

Leaching Characteristics of Modified Chitosan on Soil Contaminated by Complex Heavy Metals under Simulated Acid Rain Condition

作　　者：周雪玲 周宽 丁森旭 李思佳 常凯威 余江[1,2,3] ZHOU Xueling;ZHOU Kuan;DING Senxu;LI Sijia;CHANG Kaiwei;YU Jiang(College of Architecture and Environment,Sichuan University,Chengdu 610065,China;Institute of New Energy and Low Carbon Technology,Sichuan University,Yibin 644000,China;Yibin Institute of Industrial Technology,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学建筑与环境学院,四川成都610065 [2]四川大学新能源与低碳技术研究院,四川宜宾644000 [3]宜宾四川大学产业技术研究院,四川成都610065

出　　处：《环境科学与技术》2022年第9期49-56,共8页Environmental Science & Technology

基　　金：国家重点研发计划项目(2018YFC1802605);四川省科技重点攻关项目(2017GZ0383);四川大学-宜宾市校市战略合作专项(2019CDYB-26,2020CDYB-9)。

摘　　要：为研究在酸雨条件下改性壳聚糖对多重金属污染土壤的作用机理及环境影响,文章以环氧氯丙烷改性壳聚糖-生物炭复合材料(ECS-B)和原壳聚糖作为稳定剂,通过土柱淋溶实验探讨在模拟酸雨条件下淋出液pH、电导率(EC)和重金属(Cu、Pb、Zn和Cd)含量及形态变化特征,提出了淋溶条件下重金属的累积释放模型。研究表明,相对于对照组,加入ECS-B稳定剂淋出液pH最大升高了1.32;EC最高可达对照组的1.75倍;Cu、Pb、Zn和Cd累积含量明显降低,相比对照组分别下降了82.35%、71.47%、61.88%、90.44%;淋溶前后,各重金属残渣态最高为对照组的2.59倍。土壤中重金属的释放是受多种扩散机制控制的复杂反应过程,ECS-B稳定剂通过增加土壤盐基离子、表面络合、沉淀和离子交换等作用可以抑制酸雨对土壤中重金属的淋溶,有效减少其生态环境风险。This paper is intended to probe into the mechanism and environmental effects of modified chitosan,a kind of new materials,on heavy-metal contaminated soil under acid rain condition.Thereby,a leaching experiment of soil-column with simulated acid-rain trickling was conducted,leachate being collected from the soil-column,and ephehydrin modified chitosan-biochar composite(ECS-B)and protochitosan were used as stabilizers.The parameters of pH,conductivity and heavy metals(Cu,Pb,Zn and CD)of the leachate were analyzed in terms of contents and morphological change,and an accumulation-release model of heavy metals under leaching condition were put forward.The results of the experiment showed that compared with the control group,the pH value of leachae increased by 1.32 when ECS-B stabilizer had been added.EC changed significantly,rising up to 1.75 times of that of the control group;compared with the control group,the accumulative contents of Cu,Pb,Zn and Cd were decreased by 82.35%,71.47%,61.88%and 90.44%,respectively;and after leaching,the residual state of each heavy metal was 2.59 times higher than that of the control group.As to the study on the release of heavy metals from soil,it was considered involving a complex reaction process controlled by a variety of diffusion mechanisms.Besides,ECS-B stabilizer can inhibit the acid-rain leaching of heavy metals in soil by the increase of soil base ions,and the actions of surface complexation,precipitation and ion exchange,thus effectively reducing the ecological environment risk.

关 键 词：ECS-B 重金属 模拟酸雨 淋溶 生态环境风险 

分 类 号：X53[环境科学与工程—环境工程]