Evolution mechanism of SO2 adsorption on palygorskite (100) surface modified by APTES: Effect of different grafting modification

• Published in: Computational and theoretical chemistry Vol. 1224; p. 114130
• Main Authors: Su, Qiong, Jia, Weimin, Lu, Zhibin, Qi, Bomiao, Wang, Yanbin, Wang, Chengjun, Nian, Jingyan, Ren, Fang, Zhao, Jinqin, Liang, Junxi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2023
• Subjects: Adsorption; Density functional theory; Mechanism; Palygorskite surface; Density functional theory; APTES; PAL; Adsorption; Palygorskite surface; Mechanism
• ISSN: 2210-271X
• DOI: 10.1016/j.comptc.2023.114130

[Display omitted] •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. The effects of 3-aminopropyltriethoxysilane (APTES) with different grafting modifications on the (100) surface of palygorskite (PAL) have been examined in the current work using the first principles method. Our finding results show that the chemisorption is probably occurring because the adsorption energies of the single, double, and three-tooth APTES-PAL (100) surface systems are −66.45, −199.55, and −153.63 kJ/mol, respectively, all below −18.86 kJ/mol (or −0.2 eV). Moreover, the different grafting structures of the APTES-PAL (100) surface have different adsorption characteristics, showing that H2O was produced in the double and three-tooth APTES-PAL (100) surface systems and H2 was produced in the single-tooth APTES-PAL (100) surface system. Additionally, the rate-determining step to adjust the effectiveness of the adsorbent is the H atom broken from the NH2 group of APTES combining with the O atom of SO2. These insights will be used to develop clay composite materials in the future for gas adsorption.