Preparation of Cellulose acetate membrane by phase inversion technique and modification of surface by Copper Ferro cyanide multilayers

Abstract

Cellulose acetate (CA) membranes were prepared by wet phase inversion technique from acetone/formamide (2/1 wt/wt). The casting solution using a 20 weight-percentage polymer concentration was used for phase inversion. The solution of Potassium Ferro cyanide and Copper sulphate having molar concentration 0.1m, 0.01m, 0.001m, 0.2m, 0.02m, 0.002m were used for deposition on the surface of Cellulose acetate (CA) membrane by alternate changing the two solutions in a special cell. Values of membrane potential were measured and the transport number, fixed charged density and the permselectivity values were calculated for the electrolytes NaCl and KCl. Scanning electron micrographs (SEM) were taken for simple Cellulose acetate (CA) membrane and surface modified multilayers Cellulose acetate (CA) membrane which showed the fine deposition of multilayers of Copper Ferro Cyanide which reduced the pore size ofCellulose acetate(CA) membrane up to nano order. The values of membrane potential (with and without deposition of inorganic multilayers) slightly decreased with time reaching to a constant value, which showed initial accumulation of solution fluid within transmembrane region and saturation thereafter. The values of membrane potential increased with the deposition of multilayers showing decrease in pore size of membrane which has become of the order of nanosize. The values of transport number of cations of (K+ and Na+) were calculated using membrane potential data, which was foundin good resemblance of the ionic size of trace metal ions.