氨基生物炭覆盖对沉积物中铜、铅释放的影响

Effect of amino biochar cover on copper and lead release in sediments

沉积物是湖泊重金属污染物的源与汇,原位控制沉积物中重金属污染物的二次释放一直是研究关注的热点问题.本研究采用氨基生物炭对重金属污染沉积物进行原位覆盖,研究了不同水体酸碱度下Cu(Ⅱ)、Pb(Ⅱ)的释放规律与氨基生物炭原位覆盖对重金属污染沉积物中Cu(Ⅱ)、Pb(Ⅱ)的释放控制效果,并采用零级动力学方程和Elovich方程对Cu(Ⅱ)、Pb(Ⅱ)的释放过程进行了动力学拟合,采用单因子水质标准比较法和USEPA的健康风险评价模型对模拟湖泊水体中重金属的污染情况与健康风险进行了评价.研究结果表明,5%的氨基生物炭可降低沉积物中Cu(Ⅱ)、Pb(Ⅱ)释放量达0.744-1.015μg·mL^(−1),有效减小了水体重金属的污染水平与健康风险;是否覆盖氨基生物炭,沉积物中重金属的释放过程均符合零级动力学方程;当水体pH=7时,更有利于氨基生物炭原位修复技术的实施.

Sediment is the source and sink of heavy metals contaminants in lakes.It is of growing concern for the in-situ control of the secondary release of heavy metals from contaminated sediments.In this study,the lake sediment-water environment was simulated,amino modified biochar was used as the covering material,the release law of Cu(Ⅱ)and Pb(Ⅱ)from sediment to water was explored with different pH,the in-situ control effects of amino biochar coverage on Cu(Ⅱ)and Pb(Ⅱ)in sediments were also evaluated.In addition,the kinetic fitting of the release process of Cu(Ⅱ)and Pb(Ⅱ)were performed using zero order equation and Elovich equation,the pollution status and health risk of heavy metals in water were evaluated by single factor water quality comparison method and USEPA’s health risk assessment model.The results showed that 5%amino biochar could effectively inhibit the release of Cu(Ⅱ)and Pb(Ⅱ)in sediments by 0.744-1.015μg·mL^(−1) and reduce the pollution level and health risk of heavy metals in water.No matter whether the amino biochar was covered,the release process of heavy metals conformed to zero order equation.When the overlying water was in neutral condition,it was beneficial to the in-situ remediation of amino biochar coverage.