The abiotic removal of organic micropollutants with iron and manganese oxides in rapid sand filters for groundwater treatment

Wang, J., de Ridder, D., Sutton, N. B., Poursat, B. A.J., Saha, P. and van der Wal, A. (2023) The abiotic removal of organic micropollutants with iron and manganese oxides in rapid sand filters for groundwater treatment. Water Research, 241, 120146. (doi: 10.1016/j.watres.2023.120146) (PMID:37270951)

Abstract

Rapid sand filters (RSFs) have shown potential for removing organic micropollutants (OMPs) from groundwater. However, the abiotic removal mechanisms are not well understood. In this study, we collect sand from two field RSFs that are operated in series. The sand from the primary filter abiotically removes 87.5% of salicylic acid, 81.4% of paracetamol, and 80.2% of benzotriazole, while the sand from the secondary filter only removes paracetamol (84.6%). The field collected sand is coated by a blend of iron oxides (FeOx) and manganese oxides (MnOx) combined with organic matter, phosphate, and calcium. FeOx adsorbs salicylic acid via bonding of carboxyl group with FeOx. The desorption of salicylic acid from field sand indicates that salicylic acid is not oxidized by FeOx. MnOx adsorbs paracetamol through electrostatic interactions, and further transforms it into p-benzoquinone imine through hydrolysis-oxidation. FeOx significantly adsorbs organic matter, calcium, and phosphate, which in turn influences OMP removal. Organic matter on field sand surfaces limits OMP removal by blocking sorption sites on the oxides. However, calcium and phosphate on field sand support benzotriazole removal via surface complexation and hydrogen bonding. This paper provides further insight into the abiotic removal mechanisms of OMPs in field RSFs.

• Item Type: Articles
• Additional Information: Acknowledgments: The authors are sincerely thankful to Evides Water Company N.V. (Rotterdam, The Netherlands) and China Scholarship Council (CSC, File No. 201804910659) for financial support.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Poursat, Dr Baptiste

Creator Roles

Poursat, B.: Supervision, Writing – review and editing

• Authors: Wang, J., de Ridder, D., Sutton, N. B., Poursat, B. A.J., Saha, P., and van der Wal, A.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Water Research
• Publisher: Elsevier
• ISSN: 0043-1354
• ISSN (Online): 1879-2448
• Published Online: 01 May 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Water Research 241:120146
• Publisher Policy: Reproduced under a Creative Commons licence