Zhao Y, Chen Y, Li M, Zhou S, Xue A, Xing W
Adsorption of Hg(2+) from aqueous solution onto polyacrylamide/attapulgite. [JOURNAL ARTICLE]
J Hazard Mater 2009 Jun 18.
Polyacrylamide/attapulgite (PAM/ATP) was prepared by the solution polymerization of acrylamide (AM) onto gamma-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 Hg(2+) were investigated. The adsorption process was rapid; 88% of adsorption occurred within 5min and equilibrium was achieved at around 40min. The equilibrium data fitted the Langmuir sorption isotherms well, and the maximum adsorption capacity of Hg(2+) onto PAM/ATP was found to be 192.5mgg(-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 Hg(2+) adsorption. Hg(2+) 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.
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