Purification of water from heavy metal ions by a dynamic membrane with a surface layer of cellulose acetate

Abstract

To reduce the concentration of heavy metal ions in drinking, natural and wastewater to the established standards, a dynamic membrane with a surface layer of cellulose acetate particles on a nylon substrate was obtained. A dynamic membrane layer was formed from cellulose acetate particles with sizes from 42 to 130 nm. The cellulose acetate content was 14 % by weight, upon receipt from a 10 % solution of cellulose acetate in acetone. After applying a layer of cellulose acetate to the surface of a nylon substrate, a decrease in the specific productivity of the membranes is observed more than 10 times due to the formation of a dynamic layer on the surface and in the pores of the substrate. During the operation of the membrane for 1 hour, there is a decrease in the specific productivity of the membrane by 1.5 times and an increase in the working pressure from 0.35 to 0.41 MPa by 1.2 times. A high selectivity of the dynamic nylon-ACd membrane with respect to iron ions 96%, copper 93% and chromium 93% was established with a specific productivity of 300 dm3/m2·h and a pressure of 0.4 MPa. After purification of tap water with a dynamic membrane, the concentration of heavy metal ions does not exceed the MPC for water bodies for drinking water.