Theoretical and experimental investigation of membrane distillation

Invented in 1960s, membrane distillation is an emerging technology for water treatment attracting more attention since 1980s. There are four configurations of membrane distillation including air gap membrane distillation (AGMD), direct contact membrane distillation (DCMD), sweep gas membrane distillation (SGMD), and vacuum membrane distillation (VMD). DCMD and vacuum enhanced DCMD (VEDCMD), a variant of DCMD, were employed in this research. The objective of this study is to develop design tools for scale up of DCMD by analysing the characteristics of membrane suitable for DCMD, influences of membrane structure (hollow fibre membrane) and pressure (compressible PTFE membrane) on membrane performance, and modelling the energy efficiency of DCMD with varied process parameters. There were four major stages in this project: a) selection of a suitable flat sheet membrane for membrane distillation based on criteria such as materials used for the active layer, active layer properties and support layer properties; b) study of a hollow fibre membrane in a tubular module, and analysis of the effect of the membrane’