title: Treatment of high salinity brines by direct contact membrane distillation: Effect of membrane characteristics and salinity.
abstract: Direct contact membrane distillation (DCMD) is one of the attractive technologies for high salinity brine treatment. In this study, four polytetrafluoroethylene (PTFE) membranes were examined in treating highly concentrated salt solutions. Results showed that non-supported membranes generally have a higher overall mass transfer coefficient but porosity seems to be the most important parameter controlling membrane flux and thermal efficiency. Supported membranes with large thickness had relatively higher thermal efficiency than small thickness. This can be attributed to their reduced heat loss through heat condition. In addition, KCl, NaCl and MgCl2 solutions showed distinct trends over flux decline at high salt concentrations (⩾2.0M). The difference in flux was largely due to the discrepancy in water activities of these solutions (KCl>NaCl>MgCl2). However, the effect of viscosity on permeate flux could not be neglected for MgCl2 at high salt concentrations as the suddenly increased viscosity could lead to serious temperature polarization. This study indicates that membrane distillation is a promising technology for high salinity brine treatment.
authors.affiliation: State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste Resources, Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030006, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Li
authors.affiliation: State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste Resources, Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030006, China; School of Chemical Engineering, Qinhai University, Xining 810016, China.
authors.forename: Yunshan
authors.initials: Y
authors.lastname: Guan
authors.affiliation: State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste Resources, Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030006, China; School of Chemical Engineering, Qinhai University, Xining 810016, China. Electronic address: fqcheng@sohu.com.
authors.forename: Fangqin
authors.initials: F
authors.lastname: Cheng
authors.affiliation: School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 637723, Singapore.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
mesh_terms: D057168:Distillation; D008567:Membranes, Artificial; D016062:Porosity; D054712:Salinity; D012492:Salts / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D008567:Membranes, Artificial; D012492:Salts; D012996:Solutions; D014874:Water Pollutants, Chemical; C017082:brine
keywords: Direct contact membrane distillation; Global mass transfer coefficient; High salinity brines; Membrane characteristics; Thermal efficiency