Change of surface morphology, permeate flux, surface roughness and water contact angle for membranes with similar physicochemical characteristics (except surface roughness) during microfiltration

Abstract The aim of the present study is to confirm the extent to which smooth membrane surface (A2) improves antifouling characteristics compared with rough membrane surface (A1) during microfiltration. In the study, two membranes have similar physicochemical characteristics, except surface roughness (difference of 107.206 nm). The membranes with a rough surface (A1) and with a smooth surface (A2), respectively, were prepared by phase inversion under similar preparation conditions in order to obtain similar physicochemical properties such as material, average pore size, pore size distribution (PSD) and water contact angle values, for accurate and reliable comparisons of antifouling property. Based on the results, it was evident that final fluxes of A2 membrane with smooth surface were approximately 5% superior to those of A1 membrane with rough surface, during microfiltration of humic acid solution alone and together with calcium at 0.2 bar and 1 bar due to the difference of surface roughness. In addition to this, the extent of various antifouling characteristics on both the rough and smooth surfaces of membranes were also compared using field emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and water contact angle measurement.