Green and Sustainable Water Purification Membranes

EPA Grant Number: SU839961
Title: Green and Sustainable Water Purification Membranes
Investigators: Poler, Jordan C , Sahu, Abhispa , Rollins, Rachel
Institution: University of North Carolina at Charlotte
EPA Project Officer: Page, Angela
Phase: I
Project Period: October 1, 2019 through September 30, 2020
Project Amount: $24,867
RFA: P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet (2019) RFA Text |  Recipients Lists
Research Category: Mercury , P3 Awards , P3 Challenge Area - Safe and Sustainable Water Resources , Urban Air Toxics

Description:

Current wastewater treatment technologies are not effective at removing many small molecules and ions that are deleterious to human health. The US Environmental Protection Agency (EPA) is focused on the removal of many classes of compounds from drinking water and from wastewater including; disinfection byproducts (DBP) precursors, pharmaceuticals, personal care products, heavy metals and per- and polyfluoroalkylated substances (PFAS) that have been detected in global drinking water resources. Hence, there is a need to fabricate purification systems that would target these specific hydrophilic molecules and deliver safe and purified drinking water. In order to achieve this, a green (all-Aqueous) nanoscale anion exchange resin will be developed. This will comprise of poly(vinylbenzyl trimethylammonium chloride) (poly(vbTMAC) functionalized cellulose nanofibers. These resins work on the hypothesis that they utilize the anionic character of majority of the contaminants to remove them through electrostatic interactions. This functionalized Cellulose NanoResin (or CNR) will utilize the anion exchange resin character of the polymer and specific high surface area of the scaffold, cellulose nanofibers which will allow rapid removal of contaminants. Hence, the water purification system will be effectively fast and have ability to regenerate. Since cellulose nanofibers are abundant and inexpensive, this proposal aims to provide affordable water purification solutions to rural communities like in Brunswick County where high concentration of PFAS were found in water systems. We will analyze PFAS and other hydrophilic compounds present at environmentally relevant concentrations in water samples and aim to achieve concentrations well below maximum contaminant levels established by US EPA upon filtration. Hence, we will formulate novel CNR materials which will lead to fast and sustainable water purification systems.

Approach:

CNR will be synthesized by modified Activators ReGenerated by Electron Transfer Atom Transfer Radical polymerization where polymer will be grown and functionalized on cellulose fibers in one-pot set up. This method allows for a more predictable polymer growth rate on cellulose nanofibers. We have already synthesized and tested poly(vbTMAC) functionalized Single Walled Carbon Nanotubes (SWCNTs) as proof-of-concept for water purification membrane systems which outperformed granular activated carbon and commercialized standards (like MIEX® and DOWEX). However, SWCNTs are expensive ($750-1000). Hence, we will be redesigning the system to formulate an eco-friendly and sustainable CNR that will be an effective, green and sustainable solution to water purification.

Our goals include (a) synthesis and optimization of CNR (b) characterization and testing of as-synthesized CNR on water samples from affected communities like in Brunswick County and (c) fabrication of point-of-use water purifiers and regeneration testing for long-term lasting. We will employ green synthesis for designing our eco-friendly CNR. Since, we do not use any toxic organic reagents, the proposal aims to preserve the environment. The water purification systems will remove pervasive and ubiquitous contaminants from water which are deleterious to human health, thus improving quality of potable water consumed. Since cellulose nanofibers are inexpensive and CNR have stable, non-degrading and reusable characteristics, it will lead to economically viable to all comminutes of the society. Hence, this nanostructured membrane system is aligned along the lines of P3 approaches. We will represent our University and disseminate this project at prestigious platforms/symposiums to educate the connection between smart technologies with sustainability. This project will train rising seniors from Early College High School to intern in our lab to expose them not only to the chemistry lab etiquettes but also engage them in experiments related to green and sustainable systems for water purification. We want to specifically teach the rural communities from Brunswick County on the importance of safe and sustainable drinking water.

Expected Results:

This project will develop green, sustainable and eco-friendly membrane systems for water purification. We will optimize the synthesis to improve atom economy of reagents which aligns with green principles of chemistry. Complete characterization of CNR system will be performed to understand the fundamental relation between structure and function. Testing of several water samples containing PFAS from field sources will be performed and we expect reduction of concentration well below maximum health advisory limit. Fabrication of point-of-end water purifier system will be implemented in collaboration with engineering firm and it will deliver regeneratability properties for long-term lasting.

Supplemental Keywords:

Water filtration, cellulose nanofibers, drinking water, Perfluoroalkylated substances, anion exchange resins