【环境讲坛67期】High-Throughput Capacitive Deionization Using Hierarchical Porous Carbo
来源： 发布时间：2018-04-19 点击次数：
Deionization, also known as desalination, is an important water treatment process with a primary objective to reduce the concentration of dissolved solids (i.e., ions) in water. Deionization has wide applications in clean water supplies as well as wastewater reuse and disposal for municipality, industry, agriculture and individual consumers. Presently, deionization is mainly performed by membrane-based technologies such as reverse osmosis and electrodialysis, which require extensive pretreatment and fouling control with limited tolerance on temperature, pH, and salinity variations. Capacitive deionization (CDI) is a membrane-free desalination technology, which uses porous carbon electrodes to adsorb ions from water under an electrical field established by a direct-current potential, which has the potential to solve all the technical challenges associated with the use of semi-permeable membranes. CDI was first proposed in 1960; however, after nearly 70 years of R&D, CDI has not been developed into a technology that can compete with reverse osmosis and electrodialysis on capital cost, energy use, or treatment performance. In this presentation, I will show that the lack of progress is caused by misguided efforts to improve adsorption capacity while slow kinetics is the limiting factor (cf. Figure 1). Guided by this new insight, my research group has recently designed integrated electrodes using hierarchical porous carbon (HPC) consisting of a hierarchical structure connecting macroscopic pores to microscopic ones. Using HPC, we have designed the world’s first high-throughput CDI system, which can desalinate brackish water to drinking water at a permeate flux greater than 1 mm s-1 and an energy cost less than 0.5 kwh m-3, comparable to the standard reverse osmosis. The successful design of high-throughput CDI has made a transformative leap for membrane-free desalination R&D.
Chongzheng Na obtained his bachelor’s, master’s, and Ph.D. degrees from Tsinghua University (China), Pennsylvania State University, and the University of Michigan, all in Environmental Engineering. He was further trained in Environmental Chemistry as a postdoctoral fellow at Harvard University. Before joining Texas Tech University as an associate professor, he was an assistant professor at the University of Notre Dame in Indiana. At Texas Tech University, his teaching and research focus on developing innovative solutions of environmental challenges using nanomaterials.