Author:

Keywords:

Energy efficiency, Desalination, Top layer coating

Abstract:

Membrane distillation (MD) is an emerging separation technology, used for separation of non-volatile components from an aqueous stream. The most known application is desalination. The main advantages of MD are: the possibility to use waste heat, the high recovery rates and the easy scalable modules. In contrast to its great potential, the process has not yet been widely accepted in industry. The main problems are the lack of good performing membranes, adequate module configurations and uncertain costs. In this contribution, a commercial hydrophilic membrane is coated with a hydrophobic top layer using atmospheric plasma technology. The performance of these membranes in DCMD has been compared with the performance of commonly used and commercially available PTFE-membranes. The coatings and therefore the membrane properties have been optimized as a function of the nature of the chemical precursors and the different process parameters such as activation step, dissipated power, plasma carrier gas or gas flows. Additionally, changing the plasma treatment time for the most promising coating has enabled to link the coating thickness to the membrane performance in direct contact membrane distillation (DCMD).