Phenolic contaminants enter environmental systems through a variety of pathways, including wastewater effluent, posing a threat to environmental health. Manganese oxides represent an effective treatment method for phenolic contaminants as these minerals are highly redox active and can oxidize a variety of organic compounds, including phenols. However, studies on the oxidation of phenolic compounds by manganese oxides in environmentally relevant matrices, particularly in the presence of dissolved organic matter (DOM), are limited. DOM is a complex, heterogeneous mixture of molecules present in all natural and engineered waters that varies in composition based on source materials, biogeochemical processing, and hydrology. The role of DOM composition in inhibiting or enhancing phenol oxidation rates by manganese oxides is unknown. In this study, we investigate the influence of 12 DOM samples collected from bogs, oligotrophic lakes, eutrophic lakes, and wastewaters on the oxidation of six phenolic contaminants (i.e., Bisphenol A, Triclosan, 4-<i>tert</i>-octylphenol, 4-chlorophenol, 4-bromophenol, ad phenol) by acid birnessite. DOM composition is characterized at the bulk level using UV-vis spectroscopy, fluorescence spectroscopy, and electron donating capacity. By comparing pseudo-first order reaction rates of phenols in the presence and absence of DOM, our results show that phenolic contaminants oxidation rates can be enhanced, impeded, or not change. Through multiple linear regression analysis, we demonstrate that the variable results are dependent on both DOM composition, water chemistry, and contaminant structure. The variation in oxidation rates demonstrates the importance of assessing these contaminants in environmentally relevant matrices to design more efficient treatment processes.

Influence of diverse dissolved organic matter on the oxidation of phenolic contaminants by acid birnessite

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.