Dye sorption characters of gamma irradiated foamed ethylene propylene diene monomer (EPDM) rubber/clay composites

Composites based on gamma irradiated ethylene propylene diene monomer rubber in foam structure, loaded with different types of clays were used as adsorbents for different classes of dyestuffs (basic, acid, reactive and disperse) from aqueous solutions. The clays under investigation were Aswan clay (ASC) and sodium montmorillonite (Na-MMT). The effect of adsorbent composition, irradiation dose, pH and contact time on dye sorption was studied. It was found that the rubber composites loaded by Na-MMT gave maximum adsorption of the basic dye (∼42%) in aqueous solution, while the rubber composites loaded by AS clay gave maximum adsorption (∼28%) of the acidic dye. On the other hand, both type of clays did not show no affinity toward reactive and disperse dyes. The efficiency of dye removal was found to increase with increasing the pH and contact time. It was also observed that the irradiation dose (50 kGy) was the optimum dose for the removal of dyes for all rubber composites.