SORPTION OF IONS OF HEAVY METALS BY NEUTRAL HYPERCROSSLINKED POLYSTYRENE

Author： Tsyurupa M. P. Tarabaeva O. G. Pastukhov A. V. Davankov V. A.

ISSN： 0091-4037

Source： International Journal of Polymeric Materials, Vol.52, Iss.5, 2003-05, pp. : 403-414

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Abstract

Sorption of acetates and nitrates of mercury, lead, silver and bismuth from acetate buffers or nitric acid solutions by three types of neutral hypercrosslinked polystyrene materials has been studied. The sorbents were prepared by crosslinking either linear polystyrene or a styrene-0.7% DVB copolymer with monochlorodimethyl ether or p-xylylene dichloride, the degree of crosslinking amounting to 100% and more. The commercial hypercrosslinked sorbent, Macronet Hypersol MN-200 (Purolite), was used in the study, as well. The sorption of the above salts appears to be caused by the formation of -complexes between the metal cations and two (or more) benzene rings of the hypercrosslinked polystyrene. The formation of the complexes was found to proceed slowly at room temperature with the rate depending on the network mobility and "pore" size. The sorption isotherms for mercury proved to be characterized by strong hysteresis, but, the mercury absorbed can be easily removed by washing the sorbent with HC1 or EDTA solutions. At a concentration of less than 20 mg/ml, MN-200 exhibits the largest capacity for mercury ions, up to 200 mg/g. At higher concentrations, the sorption capacity of the polymer based on styrene-DVB copolymer rises to 400 mg (or 2 mmol Hg) per 1 g of the polymer. The sorption of the other aforementioned ions is markedly lower and reversible.