Cu(II) Adsorption from Water onto Resin of Chestnut Shell Pigment Cross-linked with Furfural

The resin of chestnut shell pigment cross-linked with furfural was fabricated by a reverse-suspension polymerization method, and its application for heavy-metal removal from water was assessed. The effects of initial pH, initial concentration and contact time on the adsorption were studied with batch equilibrium method. The kinetic data were fitted with the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model, and the equilibrium data were analyzed using the Langmuir and the Freundlich isotherms. It was found that the optimal pH value of Cu(II) solutions was 6 for the adsorption. The kinetic data were fitted better with the pseudo-second-order equation, suggesting the adsorption is a chemical process. The intra-particle diffusion was found to be one of the rate-limiting steps. The equilibrium data complied with the Langmuir isotherm, with a saturated adsorption capacity of 68.03 mg/g. The adsorption is a spontaneous exothermic process driven by both enthalpy and entropy. The good adsorption performance for Cu(II) from water shows a bright applying prospect of the resin in heavy-metal-loaded wastewater treatment.