Tailoring PAA-g-PES membranes with UiO-66-NH2 MOF for performance evaluation of laundry wastewater management: Fouling mitigation and reusability

Reclaiming and repurposing of laundry wastewater (LWW) offers a solution to mitigate water scarcity and reduce costs in water-intensive applications. LWW, generated in large volumes by households and industries like laundromats and hospitals, is a prime candidate for reuse when treated at the point of discharge for purposes like irrigation and toilet flushing. This study investigates mixed matrix membranes, specifically UiO-66-NH 2 @PAA-g-PES, fabricated via the non-solvent-induced phase separation (NIPS) method. The membrane characteristics were studied using SEM, AFM, FTIR, WCA, and TGA. These membranes were subsequently tested on three household LWW treatment, assessing permeate quality and antifouling performance. The membranes demonstrated promising outcomes, achieving remarkable reduction in total dissolved solids (TDS, 92.4 %), turbidity (99.4 %), total organic carbon (TOC, 89.5 %), and electrical conductivity (EC, 97.2 %). The high solute rejection was attributed to the adsorption properties of the metal-organic framework (MOF) and negatively charged -COO - sites of polyacrylic acid (PAA), which bound anionic surfactants and cationic ions. Fouling resistance was robust, with flux recovery ratios ( FRR ) of 81.1, 77.2, and 83.6 % for households A, B, and C, respectively, while maintaining the membrane’s structural integrity. The treated effluent met the South African National Standard (SANS 1732:2019) for single reuse of greywater for toilet flushing and subsurface irrigation and membranes demonstrated potential as a sustainable and innovative solution to water scarcity. Despite promising results, further long-term work to assess effect of LWW variability on membrane performance as well as different membrane cleaning regimes on membrane integrity.