Fabrication of Porous Chitosan Affinity Membranes for Adsorption of Copper(II): A Kinetic Study

摘要

The affinity of membranes with surface functional groups can be used as adaptive sites for separation, which are of great interest in many industrial and environmental applications. Among the various reactive functional groups, amino-group is very reactive than hydroxyl groups and can therefore be used directly as affinity adsorption sites. Recently, chitosan polymer has been increasingly studied as an absorptive material for various applications in the form of powders, flakes or gel beads. In the present study, novel semipermeable affinity membranes were fabricated from chitosan to be used in the adsorption of Cu(II) ions from aqueous solution. Porogens including polyethylene glycol and sodium chloride were tested for their effect on the membrane affinity for Cu(II) ions from aqueous solutions. Batch shake flask tests were conducted at different temperatures and the equilibrium-, Freudlich- and Langmuir-isotherms were constructed. The chitosan-NaCl membrane adsorbed almost 500 mg/g of chitosan. The kinetics of adsorption were determined according to Lagergren's models and the adsorption process was best described by the pseudo-second-order kinetic equation. The activation energy and thermodynamic parameters were also determined and the negative value of ΔG° suggested the feasibility of adsorption.