Investigation of characteristic and performance of polyvinyl chloride ultrafiltration membranes modified with silica-oriented multi walled carbon nanotubes

Abstract

The complicated and dynamic nature of membrane fouling is one of the most challenging issues that need to be addressed to obtain an efficient membrane. In this work, silica-oriented multiwalled carbon nanotubes (Si-MWCNTs) are synthesized by the sol-gel method and characterized using several analytical techniques. Novel polyvinyl chloride (PVC) ultrafiltration membranes are fabricated by incorporation of Si-MWCNT nanoparticles at varying loading levels (0-2 wt%) using the phase inversion method. Membrane morphology, chemical composition, thermal behavior, crystallinity, roughness, hydrophilicity, and mechanical strength are characterized and filtration performance is tested to compare the results with those of pristine PVC membranes. The results reveal that the addition of 0.5% Si-MWCNT nanoparticles into the casting solution exhibits the highest flux (400 L/m(2)h), sodium alginate (SA) rejection rate (96%), and flux recovery ratio (93%) due to having the highest hydrophilicity, an improved structure, and surface properties revealed by surface morphology and bulk property analysis. Furthermore, the results of dynamic mechanical and nanoindentation analyses confirm that mechanical properties such as hardness, Young's modulus, and stiffness of the pristine membrane are significantly improved by the addition of Si-MWCNT nanoparticles.