Adsorption of Hg²⁺ from aqueous solution onto polyacrylamide/attapulgite

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• 作者：Yijiang Zhao ; Yan Chen ; Meisheng Li ; Shouyong Zhou ; Ailian Xue ; Weihong Xing
• 关键词：Attapulgite ; Polyacrylamide ; Mercury adsorption ; Kinetics ; Isotherm
• 刊名：Journal of Hazardous Materials
• 出版年：2009
• 出版时间：15 November 2009
• 年：2009
• 卷：171
• 期：1-3
• 页码：640-646
• 全文大小：825 K

文摘

Polyacrylamide/attapulgite (PAM/ATP) was prepared by the solution polymerization of acrylamide (AM) onto γ-methacryloxypropyl trimethoxy silane (KH-570)-modified attapulgite (ATP). PAM/ATP was characterized using Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of contact time, adsorbent dosage, and pH of the initial solution on the adsorption capacities for Hg²⁺ were investigated. The adsorption process was rapid; 88 % of adsorption occurred within 5 min and equilibrium was achieved at around 40 min. The equilibrium data fitted the Langmuir sorption isotherms well, and the maximum adsorption capacity of Hg²⁺ onto PAM/ATP was found to be 192.5 mg g⁻¹. The adsorption kinetics of PAM/ATP fitted a pseudo-second-order kinetic model. Our results suggest that chemisorption processes could be the rate-limiting steps in the process of Hg²⁺ adsorption. Hg²⁺ adsorbed onto PAM/ATP could be effectively desorbed in hot acetic acid solution, and the adsorption capacity of the regenerated adsorbents could still be maintained at 95 % by the sixth cycle.