Membrane Distillation at the Water-Energy Nexus // Limits, Opportunities, and Challenges
By Akshay Deshmukh, Chanhee Boo, Vasiliki Karanikola, et al. Energy-efficient desalination and water treatment technologies play a critical role in augmenting freshwater resources without placing an excessive strain on limited energy supplies. By desalinating high-salinity waters using low-grade or waste heat, membrane distillation (MD) has the potential to increase sustainable water production, a key facet of the water-energy nexus. However, despite advances in membrane technology and the development of novel process configurations, the viability of MD as an energy-efficient desalination process remains uncertain.
In this review, the authors examine the key challenges facing MD and explore the opportunities for improving MD membranes and system design. They begin by exploring how the energy efficiency of MD is limited by the thermal separation of water and dissolved solutes. They then assess the performance of MD relative to other desalination processes, including reverse osmosis and multi-effect distillation, comparing various metrics including energy efficiency, energy quality, and susceptibility to fouling. By analysing the impact of membrane properties on the energy efficiency of an MD desalination system, they demonstrate the importance of maximising porosity and optimising thickness to minimise energy consumption. They also show how ineffective heat recovery and temperature polarisation can limit the energetic performance of MD and how novel process variants seek to reduce these inefficiencies. Fouling, scaling, and wetting can have a significant detrimental impact on MD performance. They outline how novel membrane designs with special surface wettability and process-based fouling control strategies may bolster membrane and process robustness. Finally, they explore applications where MD may be able to outperform established desalination technologies, increasing water production without consuming large amounts of electrical or high-grade thermal energy. They conclude by discussing the outlook for MD desalination, highlighting challenges and key areas for future research and development.
Authors
- Akshay Deshmukh
- Chanhee Boo
- Vasiliki Karanikola
- Shihong Lin
- Anthony P. Straub
- Tiezheng Tong
- David M. Warsinger
- Menachem Elimelech
Download
Royal Society of Chemistry website (e-purchase)
Published
13 Mar 2018
In
Energy & Environmental Science, 2018, Advance Article
DOI: 10.1039/C8EE00291F