Adsorptive potential of sulfonated poly(glycidylmethacrylate)-grafted cellulose for separation of lysozyme from aqueous phase: Mass transfer analysis, kinetic and equilibrium profiles

Lysozyme (LYZ) adsorption onto poly(glycidylmethacrylate)-grafted cellulose having sulfonate functional group (PGMA-g-Cell-SO3H) was investigated. PGMA-g-Cell-SO3H was prepared by graft copolymerization of glycidylmethacrylate (GMA) onto cellulose in the presence of ethyleneglycoldimethacrylate as cross linker using alpha,alpha'-azobisisobutyronitrile as initiator followed by the introduction of sulfonic acid groups through ring opening reaction of epoxide group in grafted GMA with sodium sulfite-isopropanol-water mixture. The adsorbent was characterized by means of FTIR, SEM, XRD and BET analysis. The maximum value of LYZ adsorption was found to be 74.93 and 96.21 mg/g for an initial concentration of 150 and 200 mg/L, respectively, at pH 6.0. The batch adsorption process followed pseudo-second-order kinetics and the equilibrium was achieved within 3 h. The kinetic data were also analyzed using external and intraparticle diffusion models. The intraparticle mass transfer diffusion model gave a better fit to the experimental data. Equilibrium isotherm data were well fitted with the Langmuir isotherm with maximum adsorption capacity of 141.67 mg/g at 30 degrees C. Thermodynamic study revealed an endothermic adsorption process. All of the adsorbed LYZ was eluted completely by 0.2 M CH3COOH solution. Results obtained from repeated adsorption/desorption process showed that PGMA-g-Cell-SO3H can be used for the separation of LYZ from aqueous solutions. (C) 2011 Elsevier B.V. All rights reserved.