The surface structures of asymmetric cellulose acetate membranes prepared by the phase inversion method were investigated by the atomic force microscopy (AFM). The differences in the surface morphology have been expressed in terms of four types of roughness parameters such as; roughness average (Sa), root mean square roughness (Sq), surface skewness (Ssk), and surface kurtosis (Sku). The association of the roughness characteristics with the salt rejection performance has also been investigated. The results show that the increase in the evaporation time, results in the change of the membrane morphology and rejection efficiency.
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