COMPARISON OF MEMBRANE MATERIALS FOR MEMBRANE DISTILLATION OF TREATING IMPAIRED WATER

摘要

Membrane distillation (MD) is a thermal-driven membrane technology to produce fresh water from seawater or contaminated water. Although MD has potential for many application areas, novel membrane materials for MD processing are required to improve the energy efficiency and water production rate. In this study, various microporous membranes with hydrophobic surfaces were compared for MD processing. Flat sheet membranes made of PVDF and PTFE were used for laboratory-scale experiments. In addition, carbon-nanotube were used as a new materials for MD. Results from initial comparison of water flux through MD membrane show that the water flux per unit temperature gradient was approximately proportional to hydrophobicity of the membrane materials. CNT-based membranes seem to have potential to compete with commercial-grade MD membranes in terms of water flux and salt rejection. When applied to impaired water sources, fouling due to particle deposition and organic adsorption may be anticipated due to the hydrophobic nature of most MD membranes. In addition, the effect of operating parameters such as flow velocity and temperature difference on MD efficiency was investigated.