Adsorption of Cr(VI) ions onto fluorine-free niobium carbide (MXene) and machine learning prediction with high precision
Published in Journal of Environmental Chemical Engineering, 2024
Recommended citation: Ishtiaq, R., Zahra, N., Iftikhar, S., Rubab, F., Sultan, K., Abbas, A., Lam, S.-M., Jaffari, Z. H., & Park, K. Y. (2024). Adsorption of Cr(VI) ions onto fluorine-free niobium carbide (MXene) and machine learning prediction with high precision. Journal of Environmental Chemical Engineering, 12(2), 112238. https://doi.org/10.1016/j.jece.2024.112238
Chromium in its most toxic form is discharged by plating, tanning and pigment works, and the advanced materials normally used to strip it out of water are themselves made using hazardous fluorine chemistry. A fluorine-free recipe was used here to make a niobium carbide material, which took up 93.6 milligrams of chromium for every gram of material, most of it within twenty minutes in mildly acidic water. Tracing how it works showed the chromium is held by a combination of electrical attraction, chemical conversion and hydrogen bonding rather than by any single mechanism. A machine learning model fitted to the same experiments reproduced the measured removal almost exactly, giving a compact description of how the material behaves across the range of conditions tested.