不同吸附材料对废水中Cd(Ⅱ)的吸附动力学及机理

Adsorption Kinetics and Mechanism of Different Adsorption Materials for Cd(II)in Wastewater

选择稻壳生物炭、钠基膨润土和天然硅藻土3种常见吸附材料,进行了系列吸附试验,并采用扫描电镜(SEM)和傅里叶红外光谱(FTIR)分析对吸附材料进行了表征,研究3种吸附材料对污水中Cd(Ⅱ)的吸附动力学及吸附机理,结果表明:3种吸附材料对Cd(Ⅱ)的吸附都符合准二级动力学模型,对溶液中Cd(Ⅱ)的吸附均为物理-化学复合过程。生物炭对溶液中Cd(Ⅱ)的吸附机制主要是其孔道内的钙氧化物以及表面的含氧官能团,膨润土和硅藻土则主要依赖于比表面积、表面微孔和双键官能团作用。

This paper selected the rice husk biochar,sodium bentonite and natural diatomite for adsorption materials,and conducted a series of adsorption experiments.SEM and FTIR analysis were used to characterize the adsorption materials,and the adsorption kinetics and mechanism of the three adsorption materials on Cd(II)in wastewater were studied.The results showed that the adsorption of Cd(Ⅱ)on the three adsorbents is in accordance with the pseudo second order kinetic model,and it is a physical-chemical complex process.The adsorption mechanism of biochar for Cd(Ⅱ)in solution is mainly the calcium oxide in the pores and oxygen-containing functional groups on the surface,while bentonite and diatomite mainly depend on the specific surface area,surface micropore and double bond functional groups.