Fouling and Crystallization with Hydrophobic and Superhydrophobic Hollow Fibers Membranes Using Direct Contact and Vacuum Membrane Distillation

Superhydrophobic nano-composite polypropylene hollow fibers were fabricated for membrane distillation and crystallization by using a low temperature hydrothermal approach for TiO₂ coating and fluoro-silane compounds. The membrane distillation performance was investigated during direct contact membrane distillation and vacuum membrane distillation, and the crystallization behaviors of these membranes were observed in real-time. Crystallization on hydrophobic and superhydrophobic membranes differed in terms of structure and uniformity. With the introduction of humic acid to the feed, the crystal deposition for both membranes increased in terms of. The rate of deposition was found to be lower for superhydrophobic membranes, and deposited solutes were more easily removed. Crystal nucleation and growth behaviour was consistent with those observed flat sheet membranes, indicating similar crystallization mechanisms for both membrane modules.