Synthesis of Polysulfone/PVP/Metal–Organic Framework Membranes for Batik Wastewater Treatment

This study produced and analyzed composite membranes composed of polysulfone (PSf), polyvinylpyrrolidone (PVP) and Metal–Organic Framework (ZIF-8) for treating effluent generated by the Batik industry. The incorporation of ZIF-8 was performed to enhance membrane efficiency. The findings indicated that ZIF-8 markedly enhanced hydrophilicity and pure water flux of membranes. The M-0.5 membrane containing 0.5 g of ZIF-8 demonstrated superior performance, with a water contact angle of 49.4° and a porosity of 83.5%. In contrast, the ZIF-8-free membrane (M-0) displayed a water contact angle and porosity of 66.3° and 76.7%, respectively. These combined characteristics enabled the M-0.5 membrane to achieve the highest pure water flux of 197.1 L m−2 h−1 at 5 bar. All membranes attained complete total suspended solids (TSS) rejection at 100% efficiency. Turbidity rejection rates ranged from 75% to 92%, whilst color rejection rates ranged from 65.7% to 87.6%. The maximum chemical oxygen demand (COD) rejection observed was 57.9%, achieved by the M-0.25 membrane (0.25 g of ZIF-8) at an operational pressure of 4 bar. Meanwhile, for permeability and hydrophilicity, the ideal loading is 0.5 g of ZIF-8 (M-0.5). This concentration yielded the optimal equilibrium of porosity (83.5%), the minimal water contact angle (49.4°), and the maximal pure water flux (197.1 L m−2 h−1). Nonetheless, the TDS rejection rate was rather low at 8.0–21.1%. The membrane effectively preserved effluent pH stability between 7.9 and 8.3. The aggregation of ZIF-8 at elevated concentrations diminished mechanical strength and selectivity. Additional optimization is required to equilibrate these performance indicators.