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Intact mangrove root electrodes for desalination
- Wood, Adam R., Garg, Raghav, Justus, Kyle, Cohen-Karni, Tzahi, LeDuc, Philip, Russell, Alan J.
- RSC advances 2019 v.9 no.9 pp. 4735-4743
- aerenchyma, biomass, carbonization, climate change, coasts, deionization, desalination, distillation, electrodes, energy costs, freshwater, leaves, population growth, reverse osmosis, roots, saline water, salinity, swamps, trees, water flow
- Through the benefit of billions of years of evolution, biology has developed tremendous strategies on how to co-exist in high salinity and water scarce environments. Biologically-inspired abiotic systems are becoming a central pillar in how we respond to critical grand challenges that accompany exponential population growth, uncontrolled climate change and the harsh reality that 96.5% of the water on the planet is saltwater. One fascinating biologic adaptation to saltwater is the growth of mangrove trees in brackish swamps and along the coasts. Through a process of salt exclusion, the mangrove maintains a near freshwater flow from roots to leaves to survive. One abiotic approach to water desalination is capacitive deionization, which aims to desalinate low-salinity water sources at energy costs below current technologies, such as reverse osmosis and thermal distillation. In this work, we use one-step carbonization of a plant with developed aerenchyma tissue to enable highly-permeable, freestanding flow-through capacitive deionization electrodes. We show that carbonized aerenchyma from red mangrove roots reduces the resistance to water flow through electrodes by 65-fold relative to carbonized common woody biomass. We then demonstrate the practical use of the intact carbonized red mangrove roots as electrodes in a flow-through capacitive deionization system. These findings have implications in a range of fields including water desalination, bioinspired materials, and plant functionality.