基于离子浓差极化的立体式海水淡化微流控器件研究

Microfluidic Chips for Effective Desalination of Seawater Based on Ionic Concentration Polarization

海水淡化是解决人类淡水资源匮乏的一个重要途径。现有的海水淡化技术存在设备体积大、海水淡化成本高等问题。本研究采用聚二甲基硅氧烷（PDMS）制备了基于离子浓差极化原理的海水淡化器件,采用盐溶液模拟海水,进行盐离子和水分子分离的研究。研究了不同的外加电压、盐溶液在通道中的流动速度、盐溶液通道深度和Nafion纳米通道的深度等实验条件和结构参数对微流控器件分离盐离子和水分子的影响。对微流控器件的结构参数进行了优化。实验结果表明,采用外加电压为25 V、盐溶液流速为4μL/min、盐溶液通道深宽比为1∶20、Nafion纳米通道深度为450~500μm的微流控器件进行盐溶液分离,除盐率可达到99%。研究结果对于开发新型高效、低能耗的海水淡化器件有重要的指导意义。

Desalination of seawater is one of the potential solutions to the freshwater shortage nowadays. Large-scale infrastructures and high cost are required in present desalination technologies, which hinder the widely used desalted seawater. Developing new desalination techniques could be of substantial benefit. In this study, poly （ dimethylsiloxane ） based microfluidic chips were developed to desalt the salt water by ion concentration polarization （ ICP） . Effects of the bias voltages, the flow rates of salt water, the dimensions of the micro channels and the lengths of the nano channels filled with Nafion polymer were investigated to improve the desalination efficiency. An optimized structure was obtained where the depth-to-width ratio of the micro channel was 1：20 and the length of the nano channel was 450 μm. When a bias voltage of 25 V and a flow rate of 4 μL/min of the salt water were applied, a champion desalination efficiency of 99% was reached. The study has important guiding significance for development of energy-efficient desalination devices in the near future.