The adsorption and mechanism of benzothiazole and 2-hydroxybenzothiazole onto a novel ampholytic surfactant modified montmorillonite: Experimental and theoretical study

A novel ampholytic surfactant (cationic panthenol, CP) modified montmorillonite (CPMMt) was firstly prepared and investigated its removal effect and mechanism for a class of emerging pollutants such as benzothiazole (BTH) and 2-hydroxybenzothiazole (2-OH-BTH) in water. Batch experiments were conducted to probe the effects of various conditions on the adsorption. The results showed CPMMt-1.0 had greater adsorption performance for BTH and 2-OH-BTH than Na-AMt (acidified Na-Mt), and the maximum equilibrium adsorption capacities of CPMMt-1.0 for BTH and 2-OH-BTH were three times that of Na-AMt. Zeta potential analysis, the effect experiments of solution pH combined with Multiwfn wave function program were carried out to inspect the electrostatic interaction. Furthermore, molecular dynamics simulation was applied to investigate the dynamics behavior of cationic panthenol (CP) and BTH or 2-OH-BTH in the interlamellar of montmorillonite. The results demonstrated that CP molecules presented a lateral bilayer structure, which was in good agreement with XRD experimental data, and the interaction between BTH and the surface of montmorillonite was stronger than that of 2-OH-BTH, which implies that the CPMMt-1.0 had better adsorption performance for BTH than 2-OH-BTH, which was consistent with the experimental results. The adsorption mechanism involved electrostatic interaction and hydrophobic partitioning.