Emulsion graft polymerization of glycidyl methacrylate onto bamboo fiber composites for efficient removal of lead ions from aqueous solutions

Abstract

The emulsion graft polymerization process was used to synthesize a novel polyglycidyl methacrylate grafted silanized bamboo fiber composites. The grafting percentage was assessed by varying surfactant, initiator and monomer concentrations. The surface morphologies and thermal behavior of the biocomposites were analyzed using FTIR, SEM, XRD and TGA techniques. In batch adsorption studies, the effect of adsorption parameters like pH, adsorption time, adsorbent dose and solution temperature were examined on the adsorption efficiency of lead ions. The adsorption capacity of biosorbent composites was enhanced through conversion of epoxy group of Poly glycidyl methacrylate (PGMA) into sulfonic acid groups via sulfonation process. The sulfonic acid groups were incorporated into VMBF-g-PGMA by stirring the grafted sample in H2SO4 (98 %) for 2 h at 90 °C to obtain sulfonated grafted polymer (VMBF-g-PGMA-S). By increasing the concentration of monomers up to 5 %, the maximum grafting percentage (289 %) was achieved. The grafting % increases rapidly from 0.5 to 0.20 g initiator and at 0.20 g of initiator, the highest grafting yield was 512 %. The maximum Pb+2 adsorption capacity of adsorbent was 200 mg/g. The thermodynamic parameters for pb+2 adsorption revealed an exothermic and spontaneous nature of sorption process, and the entropy change showed that there are no substantial structural changes occurred in biosorbent material. The experimental results confirmed that sulfonated biosorbent composites are effective, economical, and promising adsorbent which could be used for removal of lead and other ions from aqueous solution.

Keywords

• Bamboo fiber
• Glycidyl methacrylate
• Emulsion polymerization
• Sulfonation
• Adsorption
• Ion exchange adsorbent