This study presents the fabrication and evaluation of asymmetric polysulfone (PSF) membranes for membrane distillation (MD) and membrane distillation crystallization (MDC). A significant contribution of this work lies in the systematic investigation of the influence of three widely used solvents—N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), and dimethylformamide (DMF)—combined with varying PSF concentrations on membrane morphology and performance. The membranes were characterized using Field emission scanning electron microscopy (FESEM), Atomic force microscopy (AFM), contact angle (CA), liquid entry pressure (LEPw), porosity, and Hansen solubility analysis. Among them, the membrane labeled M2 (14 wt% PSF in DMF) exhibited the highest MD performance, with a permeate flux of 30.08 kg/m2h and low permeate conductivity of 1.62 µS/cm, reflecting the high purity of the collected water. Building on this appropriate concentrating performance, the membrane was further employed in MDC as a novel approach to facilitate lithium acetate crystallization, achieving a flux of 19.68 kg/m2h with excellent salt recovery. These results present a promising alternative to conventional fluorinated membranes and mark significant progress in developing high-performance membranes for simultaneous concentration and crystallization.

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