MXene Symposium 2025

During the MXene Symposium held in Bratislava between September 8th and 12th, Dr. Olivier Monfort and Dr Shalu have presented their results via interesting talks, both focused on the use of MXene in wastewaters treatment. You can read below the abstracts of their presentation:

MXene-Based Materials: Unlocking Advanced Oxidation in Dark Environments (S. Atri)

The increasing prevalence of contaminants of emerging concerns in water sources poses a significant threat to environmental and public health. MXenes have emerged as promising building blocks for advanced functional materials in environmental remediation. Our research focus highlights the versatility of MXene-based composites in the activation of advanced oxidation processes (AOPs) for the degradation of caffeine, a commonly used pharmaceutical and psychoactive drug. In this study, we investigate the innovative use of novel catalytic system based on MXene (Ti3C2Tx) composites decorated with spinel oxides (Co₃O₄, Fe₃O₄, and CoFe₂O₄) in AOPs based on peroxymonosulfate (PMS) activation for the degradation of caffeine in the tertiary effluent of wastewater collected from wastewater treatment plant (WWTP) Bratislava. Among the tested catalysts, MXene/CoFe₂O₄ (MXCF) exhibited superior performance, achieving complete CAF degradation within 10 minutes at natural pH using 0.2 g/L of catalyst and 0.5 mM PMS. The novelty of this work lies in the first-time demonstration of PMS activation by MXCF in dark conditions, coupled with a detailed mechanistic elucidation. The study highlights the synergistic role of Co³⁺/Co²⁺ and Fe³⁺/Fe²⁺ redox cycles, as well as surface-bound functional groups, in generating reactive oxygen species (-OH and ¹O₂), confirmed through radical scavenging and electron paramagnetic resonance (EPR) analyses. The high catalytic activity and stability of these composites make them attractive for potential integration into conventional WWTPs. Therefore, this approach offers a promising avenue for addressing the challenge of water reuse as it is directly related to the quality of wastewater treatments.

In conclusion, this work introduces an energy-efficient, scalable MXene/spinel oxide system for PMS activation, enabling sustainable removal of persistent pollutants without external energy. Future research should focus on optimizing the synthesis processes to enhance the stability and reusability of these materials, exploring their scalability for industrial applications, and investigating their performance against a broader spectrum of contaminants. Additionally, integrating MXenes with other advanced materials and technologies could lead to synergistic effects, further advancing the field of environmental remediation and contributing to sustainable water management solutions.

MXenes as innovative precursors for wastewaters treatment catalysts (O. Monfort)

Wastewater treatments are a crucial challenge for saving the environment as treated effluents are released into it. With the increase of regulations on the threshold limits for contaminants, like in the recently released European Directives No. 2024/3019 related to municipal wastewater treatments, the scientific research on innovative technologies have been now more topical than ever! MXenes and particularly nanomaterials derived from MXenes can potentially shape the future of wastewater treatments. MXenes have found plenty of applications but less in remediation processes, unless they are coupled to other nanocatalysts. Here we show MXenes and particularly Nb-substituted Ti2CTx MXenes can be excellent precursors for innovative metal oxide catalysts by retaining some characteristics of the MXenes. The present case emphasizes on the performance of such catalysts in the activation of advanced oxidation processes (AOPs) for wastewaters (WW) treatment. Thermal oxidation of (Ti0.75Nb0.25)2CTx has led to the formation of nano-heterostructures composed of TiO2 and Ti2Nb10O29, labelled here TiNbOx. The TiNbOx catalyst has triggered AOPs via peroxymonosulfate (PMS) photo-activation, and it has shown relatively high performance in the abatement of pharmaceutical contaminants namely caffeine (CAF) and sulfamethoxazole (SMX). Indeed, after 2 hours, 0.2 g/L TiNbOx in the presence of 0.5 mM PMS and UVA light can degrade 100% SMX and 91% CAF. The mechanistic elucidation has evidenced the involvement of hydroxyl and sulfate radicals and their important role in hydroxylation and ring opening reactions until reaching full mineralization. More importantly, we have conducted tests in effluents from WWTP of Bratislava-Petrzalka where 81% CAF and 91% SMX have been removed after 12 hours. Our results demonstrate MXene-derived catalysts are a promising research direction to explore. We also believe that not only MXenes but also MAX phases could be excellent candidates to design performant catalysts for wastewaters treatment. MXenes have shown they can contribute significantly to the EU Water Framework Directive.