水泥基材料铝酸三钙对水体重金属去除机制研究

Insight into the removal mechanism of heavy metals in water by cement based materials tricalcium aluminate

电镀废水中的Pb(Ⅱ)、Zn(Ⅱ)严重危害人体健康和生态环境,经济有效地处理废水中的Pb(Ⅱ)、Zn(Ⅱ)对保护人体健康和生态环境尤为重要。采用水泥基材料铝酸三钙(C_(3)A)去除Pb(Ⅱ)和Zn(Ⅱ),考察了反应时间、初始质量浓度及溶液pH对去除的影响;且结合反应后固体产物微观表征和宏观溶液组分分析,探讨了Pb(Ⅱ)和Zn(Ⅱ)的去除机制。结果表明:C_(3)A对Pb(Ⅱ)和Zn(Ⅱ)的去除分别符合准二级动力学模型(R^(2)=0.9849)和准一级动力学模型(R^(2)=0.9539),C_(3)A对Pb(Ⅱ)和Zn(Ⅱ)的最大去除量分别为8.44、13.73 mmol·g^(-1);高pH值有利于C_(3)A对金属离子的去除。C_(3)A对Pb(Ⅱ)的去除主要是碱式硝酸铅的沉淀作用和无定形氢氧化铝的絮凝作用主导,Zn(Ⅱ)主要是通过阳离子交换与沉淀作用形成ZnAl-LDH被去除。

Pb(Ⅱ)and Zn(Ⅱ)present in electroplating wastewater seriously endangers human health and ecological environment.Herein,tricalcium aluminate(C_(3)A)was employed for the removal of Pb(Ⅱ)and Zn(Ⅱ).The effects of the reaction time,initial concentration and solution pH as well as removal mechanism were investigated.The Pb(Ⅱ)and Zn(Ⅱ)removal behaviors of C_(3)A were fitted with the pseudo second-order(R^(2)=0.9849)and pseudo first-order(R^(2)=0.9539)kinetic models,respectively.The maximum removal capacities of Pb(Ⅱ)and Zn(Ⅱ)were 8.44 and 13.73 mmol·g^(-1),respectively.High pH value could enhance the removal capacity of Pb(Ⅱ)and Zn(Ⅱ).The Pb(Ⅱ)removal was dominated by the precipitation of lead and the flocculation of amorphous aluminum hydroxide.Zn(Ⅱ)was removed in the form of ZnAl-LDH via precipitation and cation exchange.