Polyelectrolyte Complex Protective Layers: A New Approach to Fouling Control and Membrane Restoration

Membrane filtration is a process in which a membrane functions as a barrier for separating materials suspended or dissolved in a fluid via sieving and affinity effects. Size based separation of the membrane filtration technologies is energy efficient because it does not require heat induced phase transition as in distillation processes. Moreover, the membrane filters are versatile and have a wide range of applications, including water purification, organics recovery, and sterilization. Nonetheless, all membrane systems suffer from membrane fouling which forms when foulants such as organic substances and microbes in the feed stream adhere to the membrane surface. Fouling layers ultimately hinder optimum membrane operation by decreasing the permeate flux rate and shortening membrane life. To control membrane fouling, polyelectrolyte complex protective layers are developed via ionic crosslinking between two oppositely charged polymers, poly(sodium 4-styrenesulfonate) and poly(4-vinylpyridine), and functionalized with antibacterial agents. The polyelectrolyte complex protective layer serves as a barrier between the foulants and underlying membrane which can be restored through complete dissolution and reapplication of the protective layer. This opens a possibility to a fully restorable membrane that releases fouling layer upon removing the polyelectrolyte complex layer and further improves distributed closed loop water recycling.

BioYechan Won joined Professor Gray's research group in 2015 as a Ph.D. student and is currently involved in the development and modification of polyelectrolyte complex coating for membrane filtration to control membrane fouling in collaboration with researchers in Ken Shull's group in Material Science and Engineering. He was previously involved in a project funded by Baxter focused on the synthesis and application of TiO2 based composites as antibacterial thin films for the touch screens of medical devices. Yechan is eager to try new things that involve synthesis, characterization, and testing. Yechan was born in Incheon, South Korea and has lived all over the world, most recently Guatemala. Yechan obtained a B.S. in Chemical Engineering from Worcester Polytechnic Institute in 2015.