Evolution mechanism of SO2 adsorption on palygorskite (1 0 0) surface modified by APTES: Effect of different grafting modification

•Three descriptors related with the adsorption performance of these materials for SO2 gas were as:•the greater binding force of APTES toward the PAL (100) surface in the double-tooth status system than in the other two teeth cases;•the higher adsorption capacity of the double-tooth status system for SO2 than that of the other two teeth cases;•the more stable formation of the double-tooth status's adsorption product in the ideal reaction routes than the other two teeth situations.