Copper(II) removal from polluted water with alumina/chitosan composite membranes

In this paper, the manufacture of a tubular alumina/chitosan composite membrane is described. A porous alumina support was manufactured with a centrifugal casting technique. Pore radii varied between 45 and 100 nm using different types of powders and powder mixtures and sintering temperatures between 1050 and 1200degreesC. Molar water permeability varied between 1 and 7 x 10(-6) mol/m(2) s Pa. which was of the same order as the molar N-2-gas permeability. The support tubes were provided with a chitosan coating of about 15 mum thickness, The porosity of the coating was controlled with a phase inversion method using silica as a porogen. These composite membranes decreased a 50 mg/l Cu2+ solution to a concentration level below 1 mg/l. Capacity of adsorption was about 0.2 g Cu2+/g chitosan. Cross-linked chitosan membranes are preferred due to their chemical stability as a function of pH. (C) 2002 Elsevier Science B.V. All rights reserved.