Cellulose and Chitosan Composite Membranes for Protein and Salt Filtration

Cellulose membrane (se) was prepared by culturing acetobacter xylinum in a media with sucrose as a carbon source and was used as a supporting membrane in this study. pore size of the supporting membrane was studied by means of molecular weight cut off (mwco) and sem micrographs. for making cellulose/chitosan composite membrane se/ch, chitosan solution was used as a coating polymer and applied by a casting method. this resulted in a smaller hydraulic permeability coefficient (lp) from 6.7 x 10-11 m3 n-1 s-1 in membrane se to 1.94 x 10-12 m3 n-1 s_1 in the composite membrane se/ch. using peg of several molecular weights as feed solution, the mwco of the se membrane was 200 kda while that of the se/ch membrane was 6 kda. the former rejected 1 g l_1 bsa by 80%. with ph between 3 and 8, the composite membrane se/ch rejected nacl and nahc03 by 50%, independent of the ph level. however, when using a divalent salt solution of mgs04 the rejection was increased up to 85%, with an optimum at ph 6-7 and a permeate flux of 5.0 l m-2 h-1 at pressures of 0.5 mpa.