Preparation of mixed matrix membranes for water treatment

• Main Author: Zhang, Haige
• Other Authors: Wang Rong
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Environmental engineering::Water treatment
• Online Access: http://hdl.handle.net/10356/40083
• Institution: Nanyang Technological University

Mixed matrix membranes or nano-composite membranes are an emerging research field in membrane area. It has drawn much attention in recent years, as the mixed matrix membrane has the potential to integrate the advantage of both polymeric and inorganic materials to enhance the performance of polymeric membranes. This FYP aims to develop porous mixed matrix membranes for water treatment by selecting proper compositions of the nano-materials. A series of characterization tests have been conducted to evaluate resultant mixed matrix membranes. In this project, polyvinylidene fluoride (PVDF)/SiO2 and PVDF/zeolite organic-inorganic UF membranes were prepared by phase inversion method with SiO2 and zeolite nano-powder dispersed in PVDF and DMAc casting solutions. The influence of addition of nano-powder on the morphologies and properties of such PVDF/SiO2 and PVDF/zeolite membranes were investigated through viscosity measurement, SEM, contact angle measurement using a goniometer and UF performance test. The results showed that the viscosity of casting solution was higher with the addition of nano-powders and the one with SiO2 nano-powder added has higher viscosity than the one with zeolite nano-powder added. The membrane morphology has a significant change with the addition of nano-particles. The finger-like structure occupies much more spaces in the membrane using zeolite nano-powder as an additive compared with the membrane cast using pure PVDF/DMAc dope. With the addition of SiO2 nano-powder into the PVDF/DMAc dope, the casted membrane achieved finger-like dominating structure. At the same time, the porosity and hydrophilicity improves when the inorganic nano-particles are added into the casting dopes and the membrane using SiO2 nano-powder as an additive has higher porosity and hydrophilicity than the one using zeolite nano-powder as an additive. In the performance test, the pure water flux increased significantly after nano-particles are added into the casting dopes and the PVDF/SiO2 membrane appeared to have the best performance.