Glyphosate Adsorption on Metal–Organic Framework M₃(BTC)₂: Mechanistic Insights and Descriptors for the Adsorption Energy from Density Functional Calculations

Adsorption-based removal has emerged as an effective strategy for mitigating the harmful impact of glyphosate. Here, the adsorption of glyphosate over the coordinatively unsaturated metal-organic framework (MOF) M₃(BTC)₂ (M = V, Cr, Mn, Fe, Co, Ni, Cu, Zn) was investigated by means of density functional theory (DFT) calculations. Among the studied MOFs, Zn₃(BTC)₂ and Ni₃(BTC)₂ show the highest adsorption energy. The Lewis acidity of the MOFs, as determined by ammonia adsorption, is found to significantly influence glyphosate adsorption. Decomposing the adsorption free energy reveals that the adsorption is dominated by the bond energy. A moderately strong linear correlation between the adsorption energies of glyphosate and ammonia suggests that ammonia adsorption can serve as a descriptor for predicting the glyphosate adsorption energy. To enhance the predictive accuracy, we employed the sure independence screening and sparsifying operator (SISSO) method, which explores a large pool of mathematical combinations of DFT descriptors to identify the most relevant ones. The resulting models enable accurate and transferable prediction of glyphosate adsorption energy.