Antiwettability and Performance Stability of a Composite Hydrophobic/Hydrophilic Dual-Layer Membrane in Wastewater Treatment by Membrane Distillation

• Published in: Industrial & engineering chemistry research 2018-07, Vol.57 (28), p.9313-9322
• Main Authors: Cheng, Dongjian, Zhang, Jianhua, Li, Na, Ng, Derrick, Gray, Stephen R, Xie, Zongli
• Format: Article
• Language: English
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.8b02027

This study investigated the performance and applicability of a composite dual-layer polytetrafluoroethylene (PTFE) membrane coated with a dense hydrophilic polyurethane layer for treating wastewater containing surfactant and solvent in a direct contact membrane distillation process. The influences of operating temperature and water recovery on bare and composite PTFE membranes were studied using simulated wastewaters containing sodium chloride together with sodium dodecyl sulfate or ethanol. In contrast to the significant wetting of bare PTFE membrane due to the adsorption of wetting agent on membrane surface, the composite membrane exhibited satisfactory antiwettability and desalination stability. The mechanism of antiwettability of the composite membrane was related to the repellent effect of hydrophobic moiety of surfactant arrayed on the hydrophilic layer of the composite membrane, which prevented the wetting agent from reaching the hydrophobic layer of membrane. The results indicate that the dual-layer membrane could be potentially used to tackle organic solvent and/or surfactant containing wastewaters.