Performance and stability evaluation of thin-film composite nanofiltration membranes under extreme oxidation conditions: Implications for reclamation of semiconductor waste solutions

The semiconductor industry consumes large quantities of ultra-pure water and high-value chemicals that turn into hazardous waste streams. Proper treatment and recovery of these waste streams are imperative for cost savings and environmental protection. In this study, we evaluated the performance and stability of thin-film composite nanofiltration (NF) membranes under exposure to strong oxidizing chemicals to assess their applicability in treatment of semiconductor waste solutions. Water flux and divalent cation (Mg²⁺) rejection of commercial acid-resistant NF membranes with three different selective layer chemistries–XUS (fully-aromatic polyamide), Duracid (polysulfonamide), and Hydracore (sulfonated-polyethersulfone)–were evaluated for 3 weeks under exposure to high concentration sulfuric acid (10 wt%) and hydrogen peroxide (1 wt%) solutions, and a mixture of the two (piranha solution). We found that all three NF membranes exhibited reasonable resistance to H₂SO₄, but they experienced significant performance deterioration when subjected to attack by H₂O₂, especially in flow-through operation mode. The changes in physical and chemical properties of the NF membranes were extensively characterized to elucidate the oxidative degradation mechanisms. We also discussed the potential and the need for developing NF membranes that are resistant to a broad range of oxidizing chemicals commonly used in high-tech industries.