TACN-Mn catalyst use in an advanced oxidation process for efficient micropollutant abatement in wastewater: A transformation study of diclofenac and sulfamethoxazole

Journal of environmental chemical engineering, vol. 10, pp. 108320

Abstract

Advanced oxidation processes (AOP) are key technologies that can degrade micropollutants in wastewater treatment. In this study, we examined how well the TACN-Mn catalyst can be applied in environmentally relevant conditions (ambient temperature and near-neutral pH) in combination with hydrogen peroxide (H2O2). Furthermore, we investigated the degradation – including the reaction pathways, kinetics and transformation products (TPs) – of the two relevant micropollutants, diclofenac (DCF) and sulfamethoxazole (SMX), in two different water matrices. The rate constants we identified compared well to literature data and showed a strong pH dependency: The pseudo first-order rate constants for DCF degradation in ultrapure water varied from 4.45 × 10-3 min-1 to 1.06 × 10-1 min-1 when the pH was increased from 7.5 to 9.0, and for SMX degradation, the rate constants ranged from 1.62 × 10-3 min-1 to 2.33 × 10-2 min-1. In wastewater, the oxidation was still effective, but at a lower rate and to a lesser extent than that in ultrapure water. TPs and reaction pathways of DCF and SMX were elucidated by LC-HRMS. TPs formed were very similar to those reported in previous studies about reactions with OH radicals. These promising results are the prerequisites for further investigations to optimize and evaluate the TACN-Mn/H2O2-AOP.

Authors 9

1. Julia Wolters Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany

2. Muhammad Usman Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany

3. Johanna Mathiä Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany

4. Dirk Dirichs Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany

5. Daniel Bastian Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany

6. Benedikt M. Aumeier Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany

7. Carsten Bolm Aachen Institute of Organic Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Organic Chemistry (IOC), RWTH Aachen University, Landoltweg 1, 52056 Aachen, Germany

8. Volker Linnemann Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany

9. Thomas Wintgens corresponding Aachen Institute of Environmental Engineering

   RWTH Aachen University

   Affiliation as printed

   Institute of Environmental Engineering (ISA), RWTH Aachen University, Mies-van-der-Rohe-Str. 1, 52074 Aachen, Germany