Screening of heterogeneous catalysts for the activated persulfate oxidation of sulfamethoxazole in aqueous matrices. Does the matrix affect the selection of catalyst? uri icon

abstract

  • The contribution of persulfate oxidation to water treatment technologies based on advanced oxidationprocesses is nowadays widely accepted. However, the importance of the water matrix on the removal of micropollu-tants has been neglected during early screening of heterogeneous catalysts, which can hinder further developmentsin the field.RESULTS: Three magnetic graphitic nanocomposites (MGNCs), obtained by carbon encapsulation of magnetite (Fe3O4), nickelferrite (NiFe2O4) and cobalt ferrite (CoFe2O4), were prepared and employed as heterogeneous catalysts in the activation ofpersulfate for the degradation of antibiotic sulfamethoxazole (SMX). The importance of the water matrix and its constituentson the performance of the MGNC materials was assessed. It was found that their relative performance in terms of oxidationof SMX in pure water decreases in the order: NiFe2O4/MGNC>Fe3O4/MGNC>CoFe2O4/MGNC. However, the order changed(Fe3O4/MGNC>NiFe2O4/MGNC>CoFe2O4/MGNC) when drinking water or secondary treated wastewater were employed. Theindividual effects of the water matrix constituents, such as bicarbonate, chloride, pH, and humic acid, or the use of addedradicalscavengers,onthecatalystperformancewereinvestigated,whiletheheterogeneousnatureoftheprocesswasconfirmedthrough leaching tests.CONCLUSION: A realistic water matrix should be considered throughout all the steps involved in the evaluation of newheterogeneous catalysts for the activated persulfate oxidation of SMX. Otherwise, misleading conclusions may be drawn,limiting potential improvements of this treatment technology.© 2019 Society of Chemical Industry

publication date

  • August 2019