Description:

Membrane distillation for hypersaline brine management: Material innovation, resilience, and energy consumption

Membrane distillation (MD), a hybrid thermal-membrane desalination technology, has recently received tremendous interest as a sustainable technology for the treatment of hypersaline brines. MD is tolerant to higher salinity (than reverse osmosis) and capable of leveraging low-grade thermal energy such as waste heat and geothermal energy. However, several fundamental aspects need to be addressed for industrial adoption of MD. In this seminar, I will present and discuss such aspects from the perspectives of material innovation, resilience, and energy consumption. First, MD performance is constrained by membrane wetting caused by low surface tension contaminants. Accordingly, omniphobic membranes with high wetting resistance have been used to improve the resilience of MD. Recently, we discovered a trade-off between membrane wetting resistance and water vapor permeability in MD. Such a trade-off, pertaining to the water-air interfacial area, needs to be considered in the design framework of high-performance MD membranes. Second, MD is susceptible to mineral scaling because scalants are accumulated in hypersaline brines. I will elucidate the different mechanisms, behaviors, and mitigation strategies of gypsum and silica scaling, two of the most common scaling in membrane desalination, highlighting the importance of understanding mineral scaling at the molecular level. Third, the economic viability of MD is determined by the availability of low-grade thermal energy, which has not been fully understood in the literature. I will describe our investigation on the feasibility of using waste heat to power MD for on-site and centralized treatment of oil and gas produced water. At the conclusion of the seminar, I will discuss the prospects and research needs associated with MD to improve environmental sustainability at the water-energy nexus. 

Bio: Dr. Tiezheng Tong is currently an assistant professor Department of Civil and Environmental Engineering at Colorado State University. He received his Ph.D. degree in Civil and Environmental Engineering from Northwestern University in 2015, and then worked as a Postdoctoral Research Fellow at Yale University. Dr. Tong holds a B.S. degree (2008) with honors in Environmental Engineering from Beijing Normal University, a M.S. degree (2010) in Environmental Science and Engineering from Tsinghua University, and a second M.S. degree (2011) in Civil and Environmental Engineering from Northwestern University. He is the leading author or co-author of ~50 peer-reviewed journal articles with citation of ~1,800 globally. He is the recipient of several academic and professional awards, including the Young Membrane Scientist Award of North American Membrane Society (2020) and Environmental Chemistry Graduate Student Award from American Chemistry Society (2012). Dr. Tong and his group applies interdisciplinary approach to improve sustainability at the water-energy-health nexus. His research interests include (i) design and development of novel membrane materials and processes for sustainable water supply; (ii) environmental applications and implications of nanotechnology; and (iii) resource recovery from wastewater treatment processes.