Influence of Unipolar Corona Discharge Parameters on the Efficiency of Separation of Oil–Water Emulsions by Cellulose Acetate Membranes

Abstract

The influence of the parameters of unipolar corona discharge (treatment time, voltage) on the productivity and selectivity of the separation of model Devonian oil-based oil-in-water emulsions using cellulose acetate (CA) membranes with a pore size of 0.2 μm has been studied. The concentrations of oil products in the model emulsion, actual formation water, and the filtrates were determined. The values of treatment time and membrane coronation voltage of 5 min and 15 kV, respectively, at which the highest flux of 20 dm³/(m² h) and a 99.3% efficiency of removal of hydrocarbons from the oil–water emulsion are achieved, have been determined. The increase in flux is due to an increase in the porosity of the filters from 65.8 to 83.6%, and greater efficiency is achieved as a result of chemical restructuring of the membrane surface. By the sessile drop method, enhancement of the surface wettability of a CA filter treated with a corona discharge (U = 15 kV and τ = 5 min), viz., a decrease in the contact angle from 72.5° to 64.6°, has been revealed According to electrophoretic light scattering data, the filtrate of the modified membrane has a lower aggregative stability and contains smaller particles compared to the untreated filter. The efficiency of salinity reduction in the formation water using a membrane treated with a corona discharge at U = 15 kV and τ = 5 min was 99.2%.