Improving cellulose acetate mixed matrix membranes by incorporating hydrophilic MIL-101(Cr)-NH₂ nanoparticles for treating dye/salt solution

Mixed matrix membranes were developed by incorporating hydrophilic MIL-101(Cr)–NH₂ nanoparticles into a cellulose acetate (CA) matrix, resulting in enhanced hydrophilicity. By enhancing hydrophilicity, mixed matrix membranes were developed to counter the common issue of fouling that occurs when using membranes for the treatment of industrial wastewater. The mixed matrix membrane structures demonstrated impressive stability, with minimal change in water contact angle over a period of 30 days. The incorporation of MIL-101(Cr)–NH₂ into the cellulose acetate membrane resulted in a reduction of the water contact angle from approximately 65.1˚ to 50.3˚, improving hydrophilicity. Even with just 1 wt% of MIL-101(Cr)–NH₂ added to the cellulose acetate matrix, the pure water flux was significantly increased by 150 % to 68.1 ± 0.87 L/m²h, due to the enhanced hydrophilicity and larger pore size while maintaining a similar level of salt rejection. The prepared membranes exhibited high rejection (>97 %) of Methyl Blue dye through size exclusion mechanism. Additionally, the flux recovery ratio (FRR) improved significantly, increasing from approximately 54 % for the unmodified cellulose acetate membrane to 82 % for the mixed matrix membrane containing 0.2 wt% MIL-101(Cr)–NH₂, demonstrating a significant improvement in the antifouling properties of the prepared membrane.