Effects of volatile organic compounds on water recovery from produced water via vacuum membrane distillation
- Publication Type:
- Journal Article
- Desalination, 2018, 440 pp. 146 - 155
- Issue Date:
© 2017 Elsevier B.V. Membrane distillation (MD) has great potentials to treat produced water in energy industries. However, volatile organic compounds (VOCs) existing in the produced water added in the fracking process can hinder the treatment process regarding two aspects: permeate quality and MD flux performance. To address this challenge, this study aims to systematically study the effects of the VOCs on the MD permeation performance and permeate quality, and the mechanism of its penetration. Acetic acid, ethylene glycol, isopropyl alcohol (IPA), and 2-Butoxyethanol (2-BE), which are commonly found in the produced water, were extensively investigated and their impacts were reviewed and compared. Among all the VOCs, 2-BE had the highest mass transfer despite its low vapour pressure and large molecule weight. Some of the VOCs had surfactant properties, which meant they could penetrate the membrane pores easily during MD process. In long-term operation, pore wetting started to appear as the salt rejection was dropping in the MD process, and flux was also decreasing. Based on the results, this study suggested that the strength of surfactant properties and intra-molecular hydrogen bonds between water molecules and VOCs are as significant as vapour pressure for the VOCs in terms of mass transfer efficiency in MD system.
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