Fabrication and modification of thin-film composite membrane for enhanced membrane performances

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Membrane application and technology have been explored due to the increase in organic and inorganic material contamination in water system. These works are to present how the physico-chemical properties of membrane surface could be modified by plasma treatment, and how such modifications could affect the performances of polymeric membrane. Specifically, ammonia plasma modification on commercial thin-film composite (TFC) membrane and evaluation of their performances with different external parameters are performed. Plasmas are applied on hydrophobic porous membrane for TFC substrate, and nano-structured materials are integrated into the polymeric membranes with or without atmospheric pressure plasma (APP) surface modification. Ammonia plasma treatment shows the surface modification of commercial TFC membranes via improving their basic physico-chemical properties such as hydrophilicity, surface free energy, ion exchange capacity (IEC) and zeta-potential with enhanced membrane performances both pure water permeability and salts rejection. Surface functional groups are created on membrane surface by plasma reaction. Plasma is an effective tool for membrane surface modification for suitability as support layers for TFC membrane fabrication through interfacial polymerization. In addition, APP treatment can modify the ordered mesoporous carbons (OMCs) to hydrophilic and modified OMCs can be dispersed in m-phenyline diamine (MPD) aqueous solution for fabricating of thin-film layer. The results show plasma modified OMCs could be well-dispersed in thin-film layer and fabricated H-OMCs TFN membranes indicate the improvement in membrane performances.