Steven Weinman, University of Alabama
Bio:
Steven T. Weinman is an Associate Professor and the Undergraduate Program Coordinator of Chemical and Biological Engineering at The University of Alabama, where he started in 2018. His research is on water purification using membranes and solvents for various water types. His group seeks to fundamentally understand the structure-property-performance relationships on RO, NF, and MF/UF membranes, adsorbents, and liquid-liquid extractions. He received his B.S. in Chemical Engineering from the University of Kentucky in 2013 and his Ph.D. from Clemson University in 2018. He was awarded a 2023 North American Membrane Society Young Membrane Scientist Award and has been selected to serve on the Early Career Editorial Board of Journal of Membrane Science and Separation and Purification Technology and the editorial board of Journal of Water Process Engineering. He has won four teaching awards as voted on by the wonderful students in the Department of Chemical and Biological Engineering at The University of Alabama. Lastly, he won the 2024 College of Engineering Faculty Excellence for Outstanding Impact and the 2024 Excellence in Community-Engaged Scholarship – Engaged Teaching & Learning from the Council on Community-Based Partnerships from The University of Alabama for his work on educating students and K-12 educators on plastics upcycling through immersive research experiences.
Abstract:
Polyamide Reverse Osmosis Membranes for the Separation of Small, Neutral Molecules
Polyamide reverse osmosis (RO) membranes have been the gold standard for water desalination for over 30 years. Even though RO membranes exhibit excellent performance rejecting salt ions, they do not reject small, neutral molecules (SNMs) at adequate levels. Due to the fast, uncontrolled nature of the interfacial polymerization (IP) reaction used to fabricate polyamide RO membranes, the polyamide layer contains both crosslinked and un-crosslinked free volume holes (pores). Because SNMs are not affected by the charge exclusion rejection mechanism that allows for high salt rejection, reducing the free volume to reduce the passage of SNMs through the membrane is needed. Surfactants regulate IP via their self-assembled network to alter the behavior between the aqueous and organic phases. This leads to the formation of more permselective membranes with a more uniform polyamide density distribution. In this study, different anionic, cationic, and non-ionic surfactants have been employed during IP for polyamide membrane synthesis. Surfactant interfacial behavior was characterized, microscale visualization using the pendant drop was analyzed, and polyamide membranes were synthesized, characterized, and performance evaluated to understand how surfactants influence a variety of membrane properties. These results will help us synthesize better performing RO membranes for new applications.