摘要
A highly efficient water purification device is designed by a combination of electrochemical deionization and microfluidic techniques. The device is constructed with seven layers, in which MnO 2 and polypyrrole are employed as positive and negative electrodes, respectively. The advantages of high sensitivity, large surface-to-volume ratio, and short ion diffusion path provided by such a microfluidic device dramatically increase the salt removal capacity (SRC) and salt removal rate (SRR) to 132 mg g −1 and 30 mg g −1 min −1 in the desalination test using a 600 mM NaCl solution. The salt removal percentage in a single-pass test of this microfluidic device using an 8 mM NaCl solution can reach 88 %, 33 times higher than 2.6 % obtained from a macro-scale experiment setup. The SRC remains over 75 % after a 180-cycle stability test. The “memory effect” provides both deionization and concentration ability without using a membrane. Over 160 mg g −1 of NaCl can be transferred from one solution to another under a 120-min deionization/concentration test. This innovative device in a semi-automatic system has been tested in real salinized underground water and seawater with the SRC of 199.4 mg g −1 and 456.6 mg g −1 for removing several ions such as Na + , K + , Mg 2+ , and Ca 2+ .