Effect of Radiofrequency Plasma Treatment on the Characteristics of Polysulfonamide Membranes and the Intensity of Separation of Oil-in-Water Emulsions

Abstract

Polysulfonamide membranes with a molecular weight cutoff of 20 kDa (pore size of 0.01 μm) have been treated with a flow of a radiofrequency (RF) capacitively coupled low-pressure glow discharge plasma in an argon and nitrogen atmosphere at an anode voltage of U_a = 1.5 kV and τ = 1.5 min. Instrumental methods of analysis have revealed the following changes in the structure of the membrane surface as a consequence of plasma treatment at the above parameters: a decrease in roughness, a decrease in the contact angle from 59.6° to 47.9°, and the formation of oxygen-containing functional groups. Experiments on the membrane separation of a 3% oil-in-water emulsion have been conducted; the results have shown that the use of plasmatreated polysulfonamide membranes leads to an intensification of the process.