UTILIZATION OF WASTES OF FOAM POLYSTYRENE AS SORBENTS

Wastes of foam polystyrene were dissolved in styrene and copolymerized with DVB and the final product was sulfonated with H2SO4 (group B). Group A of cross-linked polystyrene was synthesized using styrene and divinylbenzene (DVB) in the presence of n-heptane (macroporous ion exchangers) and then was sulfonated with H2SO4. The chemical structure of the cross-linked polymers before and after sulfonation was determined by infrared spectroscopy. The ion-exchange capacity was higher for the polymers of group A. The pore-size distribution for polymers of group A was determined and the average pore diameter (4V/A) of 39.9 nm for a representative polymer resulted. The degree of swelling of the polymers and their adsorption for methylene blue and alizarin yellow were also determined. The degree of swelling in toluene is decreased by increasing the ratio of DVB in the initial mixture and by sulfonation. The adsorption of methylene blue and alizarin yellow is strongly increased by the sulfonated polymers in comparison with the unsulfonated. As far as group B is concerned, the adsorption of alizarin yellow on the sulfonated polymers, which have higher cross-linking and lower sulfonation, increased more, especially at the initial time. The networks of both groups examined are different. The polystyrene wastes were incorporated into the whole network to an extent of 15-35%. Such investigations could contribute to the utilization of wastes of polystyrene in the direction of sorbents and especially if the polystyrene wastes are contaminated with other polymers. (C) 1995 John Wiley and Sons, Inc.