Synthesis and swelling behavior of pH-sensitive semi-interpenetrating polymer network composite hydrogels based on native and modified potatoes starch as potential sorbent for cationic dyes

Semi-interpenetrating polymer network (semi-IPN) composite hydrogels based on polyacrylamide (PAAm) as a matrix and either native potatoes starch (PS) or the hydrolyzed PS-g-PAN copolymer as entrapped polymer have been prepared using N,N-methylenebisacrylamide (BAAm) as cross-linker, ammonium persulfate as radical initiator and N,N,N′,N′-tetramethylethylenediamine as accelerator of free-radical polymerization. The composite hydrogels have been characterized by FT-IR and swelling behavior as a function of the cross-linker ratio. The kinetics of Methylene Blue (MB) adsorption on the semi-IPN composite hydrogels has been investigated as a function of the nature of the entrapped polymer in PAAm matrix. Sorption of MB on the composite hydrogels has been well described by the pseudo-first order kinetic model, which support physisorption dominates the adsorption process. The dye adsorption tests up to four adsorption/desorption cycles support the reusability of the composite hydrogels as sorbents for cationic dyes.

► Novel composite hydrogels based on native or anionically modified potatoes starch. ► Anionic semi-IPN hydrogels promising sorbents for cationic dyes. ► Anionic composite hydrogels with very fast removal of the dye with no decrease of the sorption capacity. ► Adsorption of nonionic composite hydrogel monotonously increased after regeneration with 0.1 M NaOH.