The potential of utilizing polyethylene (PE) membranes in membrane distillation (MD) for sea water desalination has been explored in this study. The advantages of using PE membranes are (1) their intrinsic hydrophobicity with low surface energy of 28-33×10N/m, (2) good chemical stability and low thermal conductivity and (3) their commercial availability that may expedite the MD commercialization process. Several commercial PE membranes with different physicochemical properties are employed to study the capability and feasibility of PE membrane application in an MD process. The effect of membrane pore size, porosity, thickness and wetting resistance on MD performance and energy efficiency have been investigated. The PE membranes demonstrate impressive separation performance with permeation fluxes reaching 123.0L/mh for a 3.5wt% sodium chloride (NaCl) feed solution at 80°C. This superior performance surpasses most of the prior commercial and lab-made flat sheet and hollow fiber membranes. A long term MD testing of 100h is also performed to evaluate the durability of PE membranes, and a relatively stable performance is observed during the entire experiment. This long term stability signifies the suitability of PE membranes for MD applications.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This research was funded by the Singapore National Research Foundation under its Competitive Research Program for the project entitled, "Advanced FO Membranes and Membrane Systems for Wastewater Treatment, Water Reuse and Seawater Desalination" (Grant number: R-279-000-336-281). The authors also thank the Singapore National Research Foundation under its Energy Innovation Research Programme for the project entitled, "Using Cold Energy from Re-gasification of Liquefied Natural Gas (LNG) for Novel Hybrid Seawater Desalination Technologies" (Grant number: R-279-000-456-279) for funding this research. We would also gratefully thank Entegris Inc. for proving the PE membranes and their support. Dr. Zuo Jian also acknowledges the World Future Foundation for his Ph.D. Prize in Environmental ans Sustainability Research 2015.