Neeraja Setlur

Graduate Student, PhD

Mentor:

Dr. Jon Chorover

Department: 

Environmental Science

Abstract: 

Title: In-Situ Sequestration of PFAS from Contaminated Groundwater using an Injectable High Affinity Cationic Hydrophobic Polymer

Authors: Neeraja Setlur, Anton Gomeniuc, James A. Field, Leif Abrell, Jim Hatton, Robert Root, Reyes Sierra Alvarez and Jon Chorover

The urgency to remove Per- and polyfluoroalkyl substances (PFAS) from water systems efficiently has increased with the rise in media coverage and political activity. PFAS, a group of over 4000 synthetic compounds, can accumulate in organisms causing numerous well-documented health issues including thyroid, heart, and liver diseases in humans and animals. Commercial PFAS remediation includes expensive, energy intensive ex-situ pump and treat methods and in-situ injections of colloidal or powdered activated carbon (CAC or PAC) or ion exchange resins (IXRs). The commercial injectables are not well developed to target a wide range of PFAS and have low adhesion to the sand, hindering the development of an effective permeable adsorptive barrier. This project synthesized and tested a high-PFAS-affinity cationic colloidal polyaniline (cPANI). cPANI characterization included its charge and aggregation with pH, specific surface area, and single-point PFAS adsorption measurements. Saturated column experiments with polymer colloid injection were used under a range of aqueous geochemical conditions (pH, ionic strength, and polymer concentrations) to quantify the transport and adhesion behavior of the cPANI in quartz sand (Qtz) and Al-hydroxide-coated quartz sand (Al-Qtz)(11 mgcPANI gQtz-1 and 7mgcPANI gAl-Qtz-1 respectively). Then column experiments were used to analyze the PFAS uptake from lab-generated contaminated water and contaminated groundwater samples from the Central Tucson PFAS Project, wells impacted by PFAS from the Davis Monthan Air Force Base (DFAMB), and Former Naval Air Station Joint Reserve Base (NASJRB) Willow Grove. cPANI was found to be an effective injectable adsorbent exhibiting comparable adsorption efficacy to CAC at environmentally relevant PFAS concentrations and significantly (over 10 times more) improved adhesion to sand under simulated aquifer conditions. This innovation holds promise for enhancing PFAS remediation efficiency.