Removal of Cr (VI) from Aqueous Solution by Super Absorbent Poly [N, N-DAPB/N, N-DMAAM/PNAAC] Hydrogels

Abstract .................................................................................................................166 12.1 Introduction .................................................................................................166 12.2 Materials and Methods ................................................................................167 12.3 Results and Discussion ...............................................................................170 Acknowledgment ..................................................................................................182 Keywords ..............................................................................................................182 References .............................................................................................................182

Fast swelling super absorbent poly [N, N-DAPB/N, N-DMAAm/PNAAc] hydrogels (A1-A5) were synthesized via microwave irradiated free radical solution polymerization of DAPB, DMAAm and PNAAc using N, N’-methylenebisacrylamide (MBAm) as crosslinker. According to swelling experiments, hydrogel A2 shows higher percentage of swelling compared to other hydrogels. The hydrogel has been characterized by FT-IR, TGA and SEM analysis. A batch system was applied to study the adsorption of Cr (VI) from aqueous solutions by super absorbent hydrogels. The experiments of Cr (VI) adsorption were performed at different initial ion concentrations, pH of the solution, adsorbent dosage, and contact time. Moreover, the optimum pH for the adsorption was found to be 1.0 with the corresponding adsorbent dosage level of 20 mg. Subsequently, the equilibrium was achieved for the 200 mg/L solution of Cr (VI) with 120 min of contact time. Furthermore, Langmuir and Freundlich adsorption isotherm was applied. The hydrogel A2 shows better results after desorption up to five cycles.