A study on adsorption behavior of newly synthesized banana pseudo-stem derived superabsorbent hydrogels for cationic and anionic dye removal from effluents

In this work, an environmentally benign superabsorbent hydrogel based on banana pseudo-stem has been synthesized by free radical graft co-polymerization of sodium acrylate (NaAc) and acrylamide (AM) on to modified banana pseudo-stem cellulose backbone using ammonium persulfate (APS) and N, N-methylene-bis-acrylamide (MBA) as initiator and crosslinker respectively. The optimum condition for initiator, monomers and crosslinker concentrations was found to be 0.0032 mol L-1, 0.013 mol L-1 and 0.00048 mol L-1 respectively. Structural confirmation of the hydrogel prepared is performed by FT-IR spectroscopy whereas the morphology and thermal properties assessments were performed by SEM and TGA analysis respectively. Swelling behavior in solutions with different pH (2, 4, 7, 9 and 12) and contact time (5-750 min) indicated 323.54 gg(-1) in pH 7 solutions for 570 min. The optimized hydrogel was used as adsorbent for methylene blue (MB) and methyl orange (MO) with a maximum adsorption of 333.3 and 124 mgg(-1) respectively. Kinetics and Isotherm adsorption studies revealed pseudo second-order and Freundlich isotherm as befitting models