Self-Cleaning Thin Film Polyamide Manganese Dioxide Nanocomposite Membrane via Peroxymonosulfate Activation

Severe surface fouling of nanofiltration (NF) has hindered its practical implementation in treating dye-containing wastewater from the textile industry. To address this fouling issue, a novel thin-film nanocomposite NF membrane (TFNx) was proposed by embedding catalytic manganese dioxide (MnO₂) nanoparticles within polyamide (PA) rejection layer to realize in situ Fenton-like advanced oxidation self-cleaning. The incorporation of MnO₂ nanoparticles was validated to moderately reduce the degree of cross-linking of the PA layer, thereby obtaining an enhanced surface hydrophilicity. The inclusion of MnO₂ nanoparticles increased the surface hydrophilicity, resulting in a higher water permeance (TFN10 18.1 ± 0.7 L m^–2 h^–1 bar^–1) that was 57.4% higher than that of the control thin film nanocomposite (TFC) membrane, while a high dye rejection was maintained. In addition, the presence of catalytically capable MnO₂ nanoparticles in the Fenton-like reaction led to membrane self-cleaning and demonstrated a better antifouling behavior. The generation of free radicals was triggered by the addition of peroxymonosulfate (PMS). Furthermore, the impacts of operational conditions on membrane self-cleaning performance and operation stability were comprehensively investigated.