Study on Dynamic Adsorption of Copper in Water by Thermally Modified Fly Ash

Abstract

The thermally modified fly ash was applied to adsorb Cu2+ in the fixed-bed column. The effects of bed height, flow rate and initial concentration on the dynamic adsorption curve of Cu2+ were investigated. On such a basis, the adsorption behavior was fitted by dynamic adsorption models. In addition, the dynamic adsorption effect of MFA on Cu2+ in the binary system was investigated. The results showed that the breakthrough time increased with the decrease of initial concentration and flow rate and the increase of bed height. The dynamic adsorption data was well fitted by the Thomas and Yoon-Nelson models. Decreasing the bed height, increasing the initial concentration and the flow rate were conducive to improve the adsorption rate. According to the characterization of MFA before and after the adsorption, the mechanisms of Cu2+ adsorption mainly include the complexation with oxygen-containing functional groups and the cation exchange. The presence of Zn2+ and Pb2+ had the inhibition effect on the adsorption performance of Cu2+,and the influence followed the order of Pb2+>Zn2+.

Keywords

• thermally modified fly ash
• dynamic adsorption
• cu2+
• adsorption model