A hybrid LMO MOF catalytic membrane with PMS activation for efficient degradation of pharmaceutical micropollutants and nanoplastics removal
Afia Sharmin, Muhammed A. Bhuiyan, Biplob Kumar Pramanik
Abstract
• Several micropollutants were degraded (95–99.5%), with 98.5% removal of PS NPs. • Superior catalysis results from Co(II)/Co(III) and Fe(II)/Fe(III) redox reactions. • The presence of MOF facilitates PMS adsorption, which enhances oxidation capacity. • Electrostatic repulsion and degradation of PS NPs aided in membrane cleaning. • Porous MOF improved water flux up to 1600 L/m 2 /hr/bar • PEG improved stability and durability of the membrane. In this study, a novel hybrid CoFe layered metal oxide (CoFeLMO) membrane was developed by integrating metal–organic framework (MOF) MIL(100)Fe and polyethylene glycol (PEG), designed specifically for peroxymonosulfate (PMS)-based advanced oxidation processes. The uniqueness of this research lies in the innovative incorporation of LMO, MOF, and PEG nanosheets onto a polyethersulfone (PES) substrate, creating a highly efficient catalytic membrane for the simultaneous removal of pharmaceutical micropollutants and nanoplastics (NPs).Among various configurations, the LMO-MOF-PEG membrane, with 20 % MOF (0.025 M) and 0.5 g of PEG, demonstrated superior performance, achieving remarkable removal efficiencies of 99.5 % for ranitidine and 98.5 % for NPs. This membrane also exhibited outstanding operational efficiency, achieving a flux of 1600 L/m 2 /hr/bar at a low PMS concentration of 0.2 mM. The degradation of ranitidine was driven by both reactive species (SO 4 •- , • OH and O 2 •- ) and non-reactive species (singlet 1O 2 ), with SO 4 •- playing a dominant role. Post-activation analysis revealed the presence of Co2 + and Fe2 + in both + II and + III oxidation, indicating the active participation of metal plots in the degradation process and confirming the membrane’s reusability. The membrane demonstrated exceptional durability, maintaining a flux recovery ratio of 97–99 % across 10 filtration cycles, even under harsh chemical conditions and across a wide pH range (2–12). Furthermore, Co leaching was minimal (2–21 µg/L) over a broad pH spectrum, even after 15 days of immersion in water.