Thermally Exfoliated g-C3N4/Ti3C2Tx MXene Schottky Junctions as Photocatalysts for the Removal of Valsartan from Aquatic Environments

In recent years, graphitic carbon nitride (g-C3N4) has gained considerable ground in the field of heterogeneous photocatalysis for the abatement of emerging contaminants from aqueous environments. Nonetheless, certain limitations, including a small surface area and a high recombination rate, limit its photocatalytic efficacy. In this study, g-C3N4 was synthesized from urea and then underwent thermal exfoliation. A portion of the exfoliated material was subsequently subjected to protonation via acid treatment, and both protonated and non-protonated variants of exfoliated g-C3N4 were combined with small amounts of Ti3C2Tx MXene. The morphology, chemical structure, and optical properties of the synthesized materials were examined using various characterization techniques. Additionally, their photocatalytic performance was evaluated through laboratory tests using the commonly detected anti-hypertensive drug valsartan as a model pollutant. The degradation kinetics of valsartan revealed that combining 1% Ti3C2Tx MXene with exfoliated g-C3N4 (both protonated and non-protonated) achieves optimal removal. Notably, the composite material 1%-pCNMX (protonated variant) displayed a 20% higher removal kinetic rate than unmodified exfoliated g-C3N4, removing a higher quantity of valsartan within the same time frame. Furthermore, all protonated composites proved more effective in degrading valsartan than their non-protonated counterparts, demonstrating the positive impact of acid treatment. The improved photocatalytic activity was attributed to the successful formation of Schottky junctions between g-C3N4 and Ti3C2Tx, which reduced the recombination rate of photogenerated charge carriers.