Thermal Stabilization of the Composite Ultrafiltration Membrane’s Surface Layer

The stability of the membrane’s dynamic layer consisting of polystyrene (PS) microparticles is studied. To improve the stability, a nylon-PS membrane is subjected to thermal treatment at temperatures of 50 to 100°C for 10 min. The effect of heat treatment on the surface of the dynamic membrane is studied by scanning electron microscopy and wetting angle measurements. The stability of the dynamic layer is achieved by 10-min thermal treatment at 50°C, with the stability of the dynamic layer increasing by a factor of four. After a backflush with a solution of anionic surfactants, the membrane’s weight does not decrease, while the weight of the initial nylon-PS membrane decreases by 0.84%. In addition, use of membranes with a thermally stabilized dynamic layer raises the degree of separation of a water–oil emulsion from 97 to 99%.