Separation of Water-Oil Emulsions Using Composite Membranes with a Cellulose Acetate Surface Layer

Abstract

Composite polytetrafluoroethylene – cellulose acetate membranes containing 8 to 19% of the latter by weight, depending on the number of composite layers, were obtained by spraying cellulose acetate suspended in acetone on the surface of a polytetrafluoroethylene substrate. It was found that the wettability of the surface layer of the membrane with a drop of distilled water increased as a result of the deposition of cellulose acetate on the surface of the initial membrane. A decrease in the specific flux of membranes from 4613 to 96 dm³ /(m²· hr) depending on the number of layers after the deposition of cellulose acetate was observed. It is shown that membrane modification leads to an increase in retention capacity of oil products from an oil-in-water emulsion from 84.0 to 99.9 %, while the size of the smallest particles separated by the membrane decreases after modification from 450 nm to 207 nm. A decrease in the absolute value of the ζ -potential with a decrease in the concentration of petroleum products in the emulsion was also detected.