甘蔗渣生物炭覆盖处理对河流沉积物中重金属释放的阻控作用

Effect of bagasse biochar mulching on the release of heavy metals from river sediments

为探究生物炭覆盖对广西车河矿区周边重金属污染河流沉积物中重金属释放的阻控作用,以甘蔗渣为原料制备甘蔗渣生物炭(BBC),通过不同覆盖量研究其对河流沉积物中As、Cd、Pb、Cu、Zn释放的阻控效率,并建立释放动力学模型。结果表明,pH=6.96时,BBC覆盖处理对沉积物中As、Cd、Pb、Cu、Zn的阻控效率随覆盖量增加而加强。当覆盖量为0.5 kg/m 2时,其重金属阻控效率均超过50%;当覆盖量为1.0 kg/m 2时,对Cu的阻控效率达到最高(89.31%)。Elovich方程能较好地模拟BBC覆盖处理沉积物中重金属的释放动力学特征。以上结果表明,在pH=6.96条件下,BBC覆盖对沉积物中As、Cd、Pb、Cu、Zn的释放有较好的阻控作用。

In order to explore the biochar mulching on the release of heavy metals from river sediments polluted by heavy metals around the tailings of Chehe,Guangxi,bagasse biochar(BBC)was prepared from bagasse.The inhibition efficiency of BBC on the release of As,Cd,Pb,Cu and Zn from river sediments was studied by different coverage,and the release kinetic model was established.The results showed that the inhibition efficiency on the release of As,Cd,Pb,Cu and Zn was directly proportional to BBC coverage,when pH=6.96.When BBC coverage was 0.5 kg/m 2,all the inhibition efficiency was more than 50%.When BBC coverage was 1.0 kg/m 2,the inhibition efficiency for Cu was the highest(89.31%).Elovich equation could well simulate the release kinetics of heavy metals in sediments treated by BBC mulching.The above results showed that BBC had a significant inhibition efficiency on the release of As,Cd,Pb,Cu and Zn from sediments to overlying water under the pH of 6.96.