Effective removals of copper (II) and lead (II) cations from aqueous solutions by polyethyleneimine-immobilized pineapple fiber

Abstract

Pineapplefiber (PF) from agricultural waste was extensively utilized as a low-cost and effective adsorbent forremovals of heavy metal cations in aqueous solution. The effects of alkali treatment and alkali treatment withpolyethyleneimine (PEI) immobilizing on thefiber surface on the adsorption performance were investigated. Thesurface characterizations of the alkali treated pineapplefiber (APF) and PEI-immobilized on APF before and afteradsorption were performed by thermogravimetry (TG), optical observation, FTIR and XPS. All adsorption sys-tems showed exothermic process and the adsorption capacity strongly depended on surface modification, pH andinitial concentration. The maximum adsorption capacities of Cu (273 mg/g) and Pb (165 mg/g) on APF-PEI were131% and 53% respectively higher than those on the APF. The adsorption was described by pseudo-second-orderkinetics andfitted well to Langmuir isotherm. Results from regeneration tests showed that the APF-PEI adsorbentcould be potentially reused with maintaining high adsorption efficiency.