Gamma irradiation synthesis and characterization of Poly(N-vinyl-2-pyrrolidone/acrylic acid) superabsorbent hydrogels for treatment of ink waste

Abstract The main purpose of this paper is to aid in solving the ink waste problem resulting from different printing processes. So, superabsorbent copolymer hydrogel composed of Poly(N-Vinyl-2- pyrrolidone) and Poly (Acrylic acid) P(NVP/AAc) was prepared using gamma radiation techniques. The study investigated the effect of irradiation dose on gelation percentage which revealed that maximum gelation percentage obtained at irradiation dose 20 kGy. Hydrogels prepared at 10 kGy exhibited a good gelation percentage 99 % corresponding to a maximum swelling percentage (∼12,000 %) at pH 11 and increased with increasing temperature to reach 48,000 % at 60 °C. Swelling kinetic studies revealed a faster water diffusion and higher swelling percentages in hydrogels prepared at 10 kGy Treatment of ink solution demonstrated the tremendous ability of P(NVP/AAc) superabsorbent hydrogels to recover water based on forward osmosis and reducing waste volume of ink and separation of water from the solid content of ink waste by 87.5 %. Additionally, the water retention of the hydrogels was studied and it was observed that water evaporation was approximately 75 % of water content within 50 h over indicating the high ability of superabsorbent hydrogels in both absorption and retains water molecules. DFT analysis revealed highest a cumulative pore volume equal 84 cc/g for P(NVP/AAc) prepared at the lowest irradiated dose corresponding to highest surface areas 136 m 2 /g. Differential Scanning Calorimeter analysis (DSC) analysis indicated changes in crystallinity and increasing in thermal stability with increasing irradiation dose. Scanning Electron Microscope (SEM) Fourier Transfer Infrared Spectroscopy (FTIR) were investigated and confirmed the functional groups and porous hydrogel structure and indicated that the a potential lack of attraction to ink molecules and a preference for water absorption.