There is a critical need to evaluate how polymers degrade and lose integrity over time when applied within different water treatment scenarios. This important topic will be addressed by evaluating the reactivity of polyamide-based nanofiltration (NF) and reverse osmosis (RO) membranes that are commonly used to purify water during desalination and water reuse. These membranes perform well but succumb to biofouling, which cannot be easily minimized, since the polymer structure readily reacts with chlorine-based disinfectants especially in saline waters. Results will be discussed which relay the important mechanisms driving the degradation of the polyamide-based monomer when exposed to free chlorine and chloramines. A strong emphasis will be made on how halide concentrations alter the chemistry, and a new mechanistic pathway will be presented. Additional discussions will examine the chemistry of the monomer in homogenous solutions and how they may not necessarily translate well to the chemistry occurring at the polymer surface, since different reaction pathways were observed when the system was scaled up. We hypothesize that changes in reactive species concentrations and reaction site structure when moving from the monomer to the three-dimensional polymer structure likely play a role. Therefore, the chemistry of the system likely exhibits profound changes as a function of scale, which must be more comprehensively evaluated in future research efforts. Such investigations have key consequences to our greater understanding of how polymers degrade and what experimental and modeling approaches may be best applied when examining their reactivity.

New Mechanistic Insights on Polyamide-based Membrane Monomer and Polymer Reactivity following Disinfection

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.