Organic-inorganic fouling behaviors of ceramic and polymeric hollow-fiber ultrafiltration membranes in semiconductor wastewater treatment

초록

Ultrafiltration (UF) membrane fouling causes substantial operational challenges and increases costs for reverse osmosis (RO)-based wastewater reclamation. In semiconductor wastewater (SWW), diverse multivalent cations promote organic-inorganic complexation, thereby causing severe membrane fouling. In this study, the organic-inorganic fouling behaviors of Al(2)O(3)ceramic and polyethersulfone polymeric UF membranes were comparatively investigated to provide an advanced understanding of distinct fouling mechanisms for stable RO pretreatment in SWW reclamation. First, model organic filtration tests showed that carboxyl-rich organics predominantly induced gel-cake layer resistance, which accounted for 57-96% of the total fouling resistance in both membranes. Moreover, metal-organic complexation has emerged as a key fouling mechanism in real SWW filtration tests, as silica-protein and multivalent cation-carboxyl complexes accumulate on both membranes. Notably, the ceramic membrane exhibited a more pronounced flux decline and higher fouling resistance, potentially due to Fe adsorption mediated by the coordination between the surface Al-OH groups and Fe(3+)ions. Scanning electron microscopy, X-ray photoelectron spectroscopy, and 3D fluorescence excitation-emission matrix confirmed that the adsorbed Fe induced the deposition of Fe-humic complexes on the membrane surface, forming an extensive fouling layer. Overall, this study reveals how metal-membrane interactions shape organic-inorganic fouling in SWW and offers broader insights into developing effective fouling control strategies for stable UF-RO pretreatment in SWW reclamation.

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