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Removing Poly- and Perfluoroalkyl Substances from Contaminated Water using Chitosan Coated Micro-polyamide
Citation:
Sahle-Demessie, E. AND A. Tegenaw. Removing Poly- and Perfluoroalkyl Substances from Contaminated Water using Chitosan Coated Micro-polyamide. ACS annual meeting, Cincinnati, OH, March 30, 2023.
Impact/Purpose:
The overall goal of the study is to identify and develop a polymeric adsorbent for the removal of emerging contaminates of interest – PFAS. The specific objectives are a) to synthesize various polyamide-based adsorbents by coating polyamide onto different supports and combine with biopolymer - chitosan, b) to perform batch and column experiments using the developed adsorbents, c) to evaluate the performance of the adsorbents in different water matrices such as MQ water, simulated wastewater, d) to study use of solubility parameter as a predictive tool to screen best adsorbent for a wide range of commonly found PFAS. The characterization of the adsorbents using FTIR, TGA, and TEM confirmed the coating of BCD onto silica particles. The adsorbents showed two to four log scale reduction in concentrations of PFAS.
Description:
Poly- and perfluoroalkyl substances (PFAS) are known as “forever chemicals” due to their ubiquitous environmental persistence and adverse human health effects. Short-chain PFAS are of increasing concern due to their high solubility and mobility in the water while possessing a persistent and toxic nature like their longer-chain analogs. The most common method for removing PFAS from water is sorption with activated carbons or ion exchange resins. Still, these adsorbents exhibit limited removal efficiency against short-chain PFAS and require frequent replacement, leading to high operational costs. In this presentation, we will discuss the potential of bio-adsorbent chitosan–modified with different polyamides as a low-cost alternative to traditional adsorbents. Chitosan-coated micro-polyamide can be an effective adsorbent for the most commonly found PFAS. However, short-chain PFAS are still a challenge. Adsorption of both short- and long-chain PFAS was tested using batch equilibrium and column flow studies. The effect of pH, the concentration of adsorbate, and the amount of adsorbent on the removal efficiency were investigated. The maximum adsorption capacity values of the different chitosan-polyamide are determined. The potential use of the Hansen solubility parameter for screening polymeric adsorbents for many PFAS has been tested. This work highlights how bio-based and waste plastic-based adsorbents may be promising materials for advancing PFAS treatment technology.