Texas Tech University
Dr. Weile Yan is an associate professor in the Department of Civil, Environmental, and Construction Engineering at Texas Tech University. She received her B.Eng. and Ph.D., both in Environmental Engineering, from the National University of Singapore and Lehigh University, respectively. She was a post-doctoral associate in Chemical and Biological Engineering at Princeton University before joining Texas Tech in 2011. Her research efforts focus on contaminant transformation mediated by earth abundant materials and environment catalysis at water-mineral interface. She pursues applications of these findings in designing more efficient and sustainable treatment systems.
Selective Ion Removal from Brine Water with Chemically Modified Electrodialysis Process
Hydraulic fracturing consumes large volumes of feed water and generates wastewater of high salinity. The presence of undesirable ions in brackish groundwater, such as barium (Ba(II) and Sr(II)), prevents its use in fracturing operations. Electrodialysis (ED) process involves feeding a continuous stream of water through a stack of membranes under electric field, where cations and anions are removed from the diluate and collected in the concentrate. The objective of this study was to develop a class of chemically modified electrodialysis (ED) membranes to achieve selective removal of Ba(II) and other multivalent cations from synthetic brine water. ED membranes were modified with crown-ethers, which are molecules with a cyclic ring structure containing ether groups. The binding selectivity of crown ethers corelate with the cavity size and the structures of the crowns and their pendants. Preliminary results obtained suggest that moderate enhancement in Ba2+ removal selectivity can be obtained with 18-crown-6 modified ED membranes. Diluate flowrate and stack current are two critical parameters that affect the ion selectivity and the energy efficiency of the process. Further study is ongoing to evaluate the effects of different membrane surface modification methods and the brine solution composition on the performance of this proposed selective ion separation process.