Investigation of characteristics and performance of polyvinylchloride (PVC) ultrafiltration membranes impregnated with silica oriented carbon nanotubes

In this thesis, silica oriented multi-walled carbon nanotubes (Si-MWCNT) were synthesized by sol-gel method and characterized using several analytical techniques. Novel polyvinyl chloride (PVC) ultrafiltration membranes were fabricated by incorporation of Si-MWCNT nanoparticles with varying loading levels (0-2 wt.%) using phase inversion method. Membrane morphology, chemical composition, thermal behavior, crystallinity, roughness, hydrophilicity and mechanical strength of the membranes were characterized using several analytical techniques and instruments. Membrane filtration performance was tested in terms of water flux, solute rejection, and anti-fouling characteristics and the results were compared to those of pristine PVC membrane. The results revealed that addition of 0.5% Si-MWCNT nanoparticles into the casting solution exhibited the highest flux (400 L/m2h), sodium alginate rejection rate (%96) and flux recovery ratio (93%) due to having the highest hydrophilicity, an improved structure and surface properties revealed by the surface morphology and bulk property analysis. Furthermore, dynamic mechanical and nanoindentation analysis results confirmed that mechanical properties such as hardness, Young's modulus and stiffness of the pristine membrane were significantly improved by the addition of Si-MWCNT nanoparticles. Key Words: Membrane, Ultrafiltration, Nanoparticle, Silica, Carbon nanotube