The removal of benzothiazole by combined inorgano-organo-montmorillonite modified with hydroxyl iron pillar and cationic panthenol intercalation: Experimental study and Multiwfn wavefunction analysis

The release of benzothiazoles into the environment has been reported to affect the ecological environment and human health, so it makes significant sense to remove benzothiazoles from aquatic environment. They are poorly eliminated by conventional wastewater treatment. A few studies have shown that benzothiazoles are difficult to bioaccumulate or sorb to particles, therefore, it is very meaningful to study their efficient adsorption. In this work, the novel combined modified montmorillonite with hydroxyl iron pillared and cationic panthenol intercalation (Fe-CPMMt) was firstly prepared and evaluated its removal effect for emerging contaminantbenzothiazole. The batch adsorption experiments showed that the maximum adsorption capacity of Fe-CPMMt for benzothiazole was 69.72 mg/g, while that of the original acidified sodium montmorillonite, alone hydroxyl iron pillared montmorillonite (Fe-AMt), alone cationic panthenol intercalated montmorillonite were 11.39 mg/g, 43.68 mg/g and 38.18 mg/g, respectively. The adsorption process for benzothiazole on Fe-CPMMt1.0 conformed well to Langmuir isotherm adsorption model and the pseudo-second-order kinetic model, and was spontaneous and endothermic. Moreover, combining with the Zeta potential values of Fe-AMt and Fe-CPMMt1.0, and with the help of Multiwfn wave function program based on density functional theory, the electrostatic attraction and coordination between Fe-AMt and benzothiazole, while the electrostatic interaction, hydrophobic partitioning, complexation, p-pi/pi, OH/pi and CH/pi interactions were verified between Fe-CPMMt and benzothiazole pollutant. The work confirmed that the novel combined modified montmorillonite with hydroxyl iron pillared and cationic panthenol intercalation has a better adsorption effect on benzothiazole. Combined with the insight into the adsorption mechanism from the atomic level, it might provide novel information for exploring a new more efficient inorganic-organic combined modified montmorillonite adsorbent for removing stubborn organic contaminants in water.