Baoxia Mi

2017 Hellman Fellow

Assistant Professor, Civil and Environmental Engineering
UC Berkeley

Project Title: Artificial Evapotranspiration for Seawater Desalination

Research Summary: We are inspired by mangrove tree’s natural transpiration process to desalinate water. Trees in general have amazing capabilities of lifting and evaporating water. As the sun heats the leaves, the water contained in those leaves turns to vapor, and evaporates away through stomata in leaves. In addition, mangrove trees have adapted a complex salt filtration system that allows them to thrive in waters doubling seawater salinity. Therefore, we plan to create an inexpensive and robust system capable of evaporating water through artificial evapotranspiration. The artificial system will be composed of synthetic tree leaves that efficiently harvest sunlight and generate localized heat on thin leaves suspended above the water to enhance the rate of evaporation, a synthetic xylem made of a hydrophilic microporous material that allow passive water transport driven by evaporation-enhanced capillary force (negative pressure), and semipermeable root to uptake water from seawater under passive filtration driven by negative pressure. Eventually, the water evaporated from the synthetic leaves will be collected and condensate to generate clean water. This technology is fully powered by sunlight and operates passively without any moving parts or pumps that require electricity or heavy maintenance. The innovation will potentially transform the development of the next-generation desalination technology for resolving the global water scarcity crisis.