Abstract
The ongoing challenge of water pollution by contaminants of emerging concern calls for more effective wastewater treatment to prevent harmful side effects to the environment and human health. To this end, this study explored for the first time the implementation of single-crystal boron-doped diamond (BDD) anodes in electrochemical wastewater treatment, which stand out from the conventional polycrystalline BDD morphologies widely reported in the literature. The single-crystal BDD presented a pure diamond (sp3) content, whereas the three other investigated polycrystalline BDD electrodes displayed various properties in terms of boron doping, sp3/sp2 content, microstructure, and roughness. The effects of other process conditions, such as applied current density and anolyte concentration, were simultaneously investigated using carbamazepine (CBZ) as a representative target pollutant. The Taguchi method was applied to elucidate the optimal operating conditions that maximised either (i) the CBZ degradation rate constant (enhanced through hydroxyl radicals (•OH)) or (ii) the proportion of sulfate radicals (SO4•−) with respect to •OH. The results showed that the single-crystal BDD significantly promoted •OH formation but also that the interactions between boron doping, current density and anolyte concentration determined the underlying degradation mechanisms. Therefore, this study demonstrated that characterising the BDD material and understanding its interactions with other process operating conditions prior to degradation experiments is a crucial step to attain the optimisation of any wastewater treatment application.
Original language | English |
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Article number | 123705 |
Number of pages | 10 |
Journal | Environmental Pollution |
Volume | 347 |
DOIs | |
Publication status | Published - 2024 |
Funding
This research received funding from the EU Framework Programme for Research and Innovation Horizon 2020 under grant agreement no 861369 (MSCA-ETN InnovEOX) and from the KU Leuven Industrial Research Council under grant number C24E/19/040 (SO4ELECTRIC). S.B. and J.G.B. acknowledge financial support from the Dutch Research Council ( NWO ) through the Open Technology Programme (project no 16361 ). André F. Sartori, Matthias Schreck (University of Augsburg, Germany) and Martin Fischer (Augsburg Diamond Technology GmbH, Germany) are acknowledged for their support with the preparation of the single-crystal BDD electrode, and Clive Hall from Mintres B.V. (Cuijk, The Netherlands) is acknowledged for supplying the free-standing BDD material.Keywords
- boron-doped diamond (BDD)
- Electrochemical advanced oxidation processes (eAOPs)
- polycrystalline
- single-crystal
- wastewater treatment