Hydrophilic modification and anti-fouling properties of PVDF membrane via in situ nano-particle blending

Abstract

Two hydrophilic poly-vinylidene fluoride (PVDF) ultrafiltration membranes were prepared via in situ embedment of nanoparticles (NP), i.e., TiO₂ and Al₂O₃, respectively, and their anti-organic-fouling and anti-biofouling were comprehensively investigated. Characterization of modified PVDF-NP membranes by XRD and FTIR exhibited that nanoparticles were embedded successfully. Series of fast filtration tests demonstrated that in contrary to virgin PVDF membrane, PVDF-NP membranes have high permeability and anti-organic-fouling ability by decreasing the possibility of organic matters deposition and accumulation. Co-existed Ca²⁺ in feed solution deteriorated the organic fouling in virgin PVDF and PVDF-NP membranes, which was mainly caused by gelation of macromolecular foulants. PVDF-NP membranes were used to form MBR modules for domestic wastewater treatment, and the long-term monitoring evidenced that hydrophilic modified membranes achieved stably high COD and \( {\mathrm{NH}}_4^{+}-\mathrm{N} \) rejection efficiencies, and better organic rejection capability than mAO process. PVDF-NP membranes possessed consistently high anti-biofouling ability to maintain stable membrane permeability.