Separation of methanol/methyl tert-butyl ether using sulfonated polyarylethersulfone with cardo (SPES-C) membranes

► The hydrophilicity of the membranes increased with increasing sulfonation degree. ► SPES-C membranes showed improved PV performance. ► Sorption selectivity increased with increasing sulfonation degree (SD). ► Diffusion selectivity changed slightly and then decreased sharply with increasing SD.