Decipher the molecular descriptors and mechanisms controlling sulfonamide adsorption onto mesoporous carbon: Density functional theory calculation and partial least-squares path modeling

Mesoporous carbons (MCs) exhibit excellent removal efficiencies to various organic chemicals. However, how the properties of chemicals influence the adsorption mechanisms and further determine their adsorption onto MCs are poorly understood. We investigated the adsorption of 22 sulfonamides (SAs) onto four MCs, and further uncovered the major molecular descriptors and adsorption mechanisms influencing the adsorption by density functional theory (DFT) and partial least-squares path modeling (PLS-PM). The results revealed that the excess molar refraction (E), McGowan's molar volume (V), energy of the highest occupied molecular orbital (E-HOMO), hardness (H), and most positive net charge on carbon atom (Q(c)(+)) were identified as the indirect factors affecting the distribution coefficient (logK(D)), by influencing the BE(pi-pi), BE(H), and logK(ow). BE(pi-pi) and logK(ow) displayed significant direct impacts on logK(D) (p < 0.05), while BE(H) showed insignificant direct influences on logK(D) (p > 0.05). The PLS-PM results indicate the main driving forces for SAs adsorption including pi-pi interactions, hydrophobic effects, and hydrogen bonding. This study provides a new perspective on revealing the adsorption mechanisms, and the identified factors can be used to develop the quantitative model to further predict the adsorption of SAs onto MCs.

Automated summary

This study investigates the adsorption of sulfonamide compounds onto mesoporous carbons and identifies the factors influencing the adsorption mechanisms. The results reveal that factors such as excess molar refraction, molar volume, energy of the highest occupied molecular orbital, hardness, and net charge on carbon atom indirectly affect the adsorption. The main driving forces for adsorption are found to be π-π interactions, hydrophobic effects, and hydrogen bonding.