Quantitative structure-property relationship (QSPR) study for the degradation of dye wastewater by Mo-Zn-Al-O catalyst

Quantitative structure-property relationships (QSPR) between the structure of dyes and the discoloration rate of dyes were established to predict the discoloration rate of dyes in catalytic wet air oxidation (CWAO) process. The DFT-based quantum chemical descriptors were obtained at the B3LYP/6-31G (d,p) level and partial lease squares (PLS) regression was employed for QSPR model development. The discoloration rate of dyes was recorded in the CWAO process by Mo-Zn-Al-O catalyst under room conditions. The optimal QSPR model with a cross-validation Q2(cum) value of 0.845 and R value of 0.9893 indicates that the QSPR model has sufficient predictive ability and robustness. Two components were selected in the model, which account for 0.733 of the variance of the predictor variables and 0.979 of the variance of the dependent variable. The absolute values of W*[1] for that absolute hardness (η) and the most negative atomic net charges of the molecule (q‑) were 0.806657 and 0.561769 demonstrates that η and q− are the main causes for the first component. The second PLS component is loaded on descriptor dipole moment (μ) for which the W*[2] values were 0.906712. The equation was obtained with the descriptors: Y = 51.5042 + 252.644η + 0.899607μ + 102.427q−(Y is the discoloration rate of dyes). The obtained QSPR model could be used for predicting the discoloration rate of dyes and also reveals our previous suspicion of catalytic mechanism.