PFAS Adsorption on Water Treatment Residues

Mandal, Jajati

Abstract

Per- and polyfluoroalkyl substances (PFAS) represent a family of emerging persistent organic pollutants. In the face of the escalating global challenge of PFAS contamination in water, this study focuses on the removal of, three PFAS viz. perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexanesulfonate (PFHxS) via adsorption on three types of water treatment residues (WTR1 = no activated carbon with medium copper content, WTR2 = activated carbon with low copper content, WTR3 = activated carbon with high copper content). The adsorption kinetics study revealed a pseudo 2nd order kinetics for adsorption of all PFAS. The adsorption isotherms followed the order PFOS > PFOA > PFHxS irrespective of WTRs, and best fitted to the Freundlich adsorption isotherm suggesting that their adsorption on heterogeneous surfaces involves complex and multilayer interactions and indicating diverse adsorption sites and non-linear dynamics. The adsorption capacity for the WTR with activated carbon (WTR2 and WTR3) was greater as compared to that with no activated carbon (WTR1). The maximum adsorption capacity of WTR3 for PFAS, as determined by the Langmuir isotherm model, was 0.676 mg g-1 for PFOS, 0.257 mg g-1 for PFOA and 0.170 mg g-1 for PFHxS. Similarly, a higher value of Temkin constant from Temkin adsorption isotherm was found for PFOS followed by PFOA and PFHxS, irrespective of WTRs suggesting a stronger interaction between the adsorbate and adsorbent. This study suggests that WTRs with activated carbon could be a sustainable option for the remediation of PFAS-contaminated water, provided high Cu content could appropriately be managed.

Citation

Mandal, J. (2024, September). PFAS Adsorption on Water Treatment Residues. Presented at International Conference on Emerging Trends in Water Treatment 2024, Mikkeli, Finland

• Presentation Conference Type: Speech
• Conference Name: International Conference on Emerging Trends in Water Treatment 2024
• Conference Location: Mikkeli, Finland
• Start Date: Sep 17, 2024
• End Date: Sep 19, 2024
• Deposit Date: Nov 12, 2024
• Related Public URLs: https://www.lut.fi/en/etwt-2024