Abstract

With the aim of achieving new highly porous, water-insoluble solid adsorbents for pollutants in water whose adsorption mechanism is based on aromatic-aromatic interactions, solid materials bearing charged aromatic groups have been developed from a family of copolymers of sodium styrene sulfonate and glycidyl methacrylate synthesized by free radical copolymerization both in DMF and in DMF/H2O, with comonomer molar ratio ranging between 0.2 and 0.8. The copolymers have been rationally designed to furnish hydrophilic functional negatively charged aromatic rings to allow aromatic-aromatic interaction with cationic aromatic pollutants, and hydrophobic functional monomers able to trigger crosslinking reactions through ring opening of epoxy groups by thermal treatment. All these copolymers form hydrogels in water. However, foams with closed cell structure were formed with the copolymer synthesized in DMF at a 0.2/0.8 NaSS/GMA molar ratio in the feed upon thermal treatment for 5-15 min at 270 degrees C, that resulted in non-soluble, elastic, hard, and fragile solid materials. Volume expansion stood around 30-fold the original volume, and porosity of the resulting expanded objects reached values higher than 73 %. Due to the large surface area of these foams and the presence of the benzene sulfonate moieties, the materials showed maximum adsorption capacity of around 200 mg of the model dye methylene blue per g of material, with a high adsorption rate. Interestingly, the absorbent foams showed catalytic activity towards photodegradation of the dye and allowed reusing the materials for at least six cycles.