Investigation on Poly(methacrylic acid)-Grafted Cellulose/Bentonite Superabsorbent Composite: Synthesis, Characterization, and Adsorption Characteristics of Bovine Serum Albumin

Investigation on adsorption behavior of bovine serum albumin. (BSA): on superabsorbent composite is critical for many analytical and biomedical applications In this study, a novel `poly(methacrylic acid) grafted cellulose/bentonite (PMAA-g-Cell/Bent) superabsorbeut composite Was synthesized by graft copolymerization reaction of methacrylic acid on cellulose (Cell) in the presence of bentonite (Bent) using N,N'-methylenebisacrylamide as a cross;linker. The original Cell and Bent and composite were analyzed using FTIR, XRD, SEM, TG, and potentiometric titrations: The ability of the composite to adsorb BSA from aqueous solutions has been studied at different optimized conditions. The optimum pH range for the maximum uptake of BSA was 4.5. Maximum adsorption of the BSA, i.e, 99.7%, was achieved from an initial concentration of 100 mg/L using 1.0 g composite at pH 4.0. The equilibrium time of adsorbing BSA was about 3 h. Experimental kinetic data were tested with pseudo-first-order and pseudo-second-order kinetic equations. The experimental data fitted very well with the pseudo-second-order kinetic model, indicating the coexistence of chemisorptions and physisorption. It was also found that the film diffusion played an important role in the rate control of the adsorption process. The applicability of the Langmuir, Freundlich, and Sips isotherms was used to try to describe the experimental isotherm equilibrium data The BSA adsorption isotherm was best represented by the Sips model, which indicates a multilayer adsorption at lower concentration and monolayer at higher concentration. The equilibrium sorption capacity of 196.15 mg/g was determined from the Sips isotherm, The results of the six time consecutive adsorption-desorption cycles showed the feasibility of repeated use of this composite.