Preparation And Antifouling Property Of Polyethersulfone Ultrafiltration Hybrid Membrane Containing Halloysite Nanotubes

Polyethersulfone (PES) is widely used for the preparation of ultrafiltration (UF) membranes due to its excellent chemical resistance, good thermal stability, oxidation resistance and mechanical properties. However, the hydrophobic nature of PES often causes fouling of the pure PES membrane in water treatment. Thus, it is necessary to enhance the surface hydrophilicity of PES membranes and improve the antifouling performance. In this thesis, physical blending was used to construct antifouling PES UF membrane. The main contents are as follows:(1) Polyethersulfone (PES) ultrafiltration membranes blending with halloysite nanotubes loaded with copper ions (Cu2+-HNTs) were developed for the effective biofouling control. Cu2+-HNTs were synthesized by chemical modification of HNTs with silane coupling agent, and then mixed with copper dichloride for complexing copper ions. The morphology and performance of the membranes were characterized by SEM, AFM, TEM, contact angle, and mechanical measurements. The hybrid membranes were shown to be more hydrophilic, with a higher pure water flux. Mechanical test revealed that the mechanical strength of hybrid membranes increased as the addition of Cu2+-HNTs particles. It was also found that Cu2+-HNTs were dispersed uniformly in the membrane. The antibacterial test indicated that the hybrid membranes showed good antibacterial performance against Gram-negative bacteria (E. coli) and Gram-positive bacteria (S. aureus) and the hybrid membranes had a good antibacterial duration.(2) Polyethersulfone (PES) ultrafiltration membranes blending with halloysite nanotubes-poly (4-vinylpyridine)-Cu nanoparticles (P4VP-HNTs-Cu) were developed for the purpose of endowing membrane with both antibacterial and antifouling properties. P4VP-HNTs-Cu were synthesized by chemical modification of HNTs with4-vinylpyridine via reverse atom transfer radical polymerization (RATRP), and then mixed with copper dichloride for complexing copper ions, finally copper nanoparticles were formed using sodium tetrahydroborate as reducing agent. The morphology and performance of the membranes were characterized by SEM and contact angle. The hybrid membranes were shown to be more hydrophilic, with a higher pure water flux. The thickness of the thin separating layer on the top tends to decrease with P4VP-HNTs-Cu addition. The antibacterial test indicated that the hybrid membranes showed good antibacterial performance. The adsorption experiments indicated that the adsorption amounts of BSA on the hybrid membranes were dramatically decreased. In addition, the leaching test indicated that the copper on the hybrid membranes was stable.(3) Polyethersulfone (PES) ultrafiltration membranes blending with2-methacryloyloxyethyl phosphorylcholine-halloysite nanotubes (HNTs-MPC) were developed for the purpose of endowing membrane with antifouling property. HNTs-MPC was synthesized by chemical modification of HNTs with2-methacryloyloxyethyl phosphorylcholine via reverse atom transfer radical polymerization (RATRP). The morphology and performance of the membranes were characterized by SEM and contact angle. The hybrid membranes were shown to be more hydrophilic, with a higher pure water flux. The thickness of the thin separating layer on the top tends to decrease with HNTs-MPC addition. The adsorption experiments indicated that the adsorption amounts of BSA on the hybrid membranes were dramatically decreased. Protein ultrafiltration experiment also showed that the antifouling ability of membranes with additive of HNTs-MPC were better than pure PES membrane. In addition, the long term ultrafiltration experiment showed an ideal stability of hybrid membranes.