The separation of charged species such as salts, microplastics, and other trace contaminants from water is one of the most significant technological challenges facing mankind. Present separation strategies are energetically expensive and improvements in separation and energy efficiency are incremental. Accordingly, alternative separation techniques must be explored. We have developed a technique called faradaic ion concentration polarization which utilizes local electric field gradients formed by electrochemical processes to manipulate charged species within microscale systems. Herein, we describe the continuous focusing, sorting, and separation of microplastics by faradaic ion concentration polarization within a trifurcated microchannel. This is accomplished by formation of local electric field gradients at two wirelessly-controlled bipolar electrodes patterned along the channel length and operated simultaneously by a single voltage source. Electric field profile, conductivity, and current measurements collected during independent or tandem operation of the bipolar electrodes further characterize the effect of simultaneous faradaic ion concentration polarization along the channel length. These findings are significant because they demonstrate that serial faradaic ion concentration polarization permits the controlled manipulation of charged species within a robust and experimentally simple system.

Electrokinetic focusing, sorting, and separation of microplastics by serial faradaic ion concentration polarization

2019 Fall National Meeting

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