Membrane fouling in vacuum membrane distillation for ionic liquid recycling: Interaction energy analysis with the XDLVO approach

• Published in: Journal of membrane science 2018-03, Vol.550, p.436-447
• Main Authors: Wu, Huanhuan, Shen, Fei, Wang, Junfeng, Wan, Yinhua
• Format: Article
• Language: English
• Subjects: Fouling; Interaction energy; Ionic liquid; Membrane distillation; XDLVO theory
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2018.01.018

Membrane fouling, essentially originated from the interactions between foulant and membrane surface, is a big obstacle to use membrane distillation (MD) for ionic liquid recycling from its aqueous solution. By applying the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) approach and surface element integration method, this study mainly investigated the fouling behavior of three kinds of hydrophobic membranes during the vacuum MD (VMD) separation of 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) solutions. Effects of membrane surface chemical properties (e.g. elemental composition and zeta potential), membrane surface morphology (e.g. roughness), and [Bmim]Cl concentration on the interaction energy between [Bmim]Cl and membrane surface were studied. The results showed that the Lifshitz-van der Waals (LW) and electrostatic interaction (EL) components were positive (repulsion), while the acid-base (AB) interaction component was negative (attraction). Roughening membrane surface significantly decreased the interaction energy barrier, indicating a greater risk of being fouled. Even so, membrane surface chemical properties had more important impact on membrane fouling than surface morphology. Energy barrier would be also reduced when [Bmim]Cl concentration increased, signifying a severer membrane fouling potential in a concentration process. These results were expected to help to understand ILs-fouling mechanism in VMD process and guide the selection and fabrication of promising membrane for ILs recovery. •Membrane fouling in VMD separation of [Bmim]Cl solution was investigated by XDLVO.•Rough membrane was more likely to be fouled due to the decreased energy barrier.•Membrane surface chemistry played a major role in impacting membrane fouling.•High [Bmim]Cl concentration increased the risk of membrane fouling.