Coupling humic acid in Fe-bearing montmorillonite for enhanced adsorption and catalytic degradation of tetracycline

Clay-based materials have attracted attention owing to their dual effects of adsorption and advanced oxidation degradation in removing organic pollutants. In this study, the introduction of humic acid (HA) in the Fe-bearing montmorillonite (Fe-Mt) nano platform enhanced its tetracycline (TC) adsorption and degradation were investigated. The result showed that the adsorption and degradation efficiency of humic acid/poly-hydroxyl-iron/montmorillonite (HA-Fe-Mt) was greater than those of Fe-Mt. The adsorption performance and characterization confirmed that HA-Fe-Mt had more functional groups, stronger hydrophobic character, and higher specific surface area. The introduction of HA onto the Fe-Mt platform enhanced its specific surface area, electrostatic interaction, and hydrophobic character, therefore providing more active sites to interact with the carbonyl and amide groups of TC. Moreover, the catalytic performance and characterization results revealed that HA-Fe-Mt had greater persulfate (PS) activation, the coupled HA would speed up the transmission of electrons between Fe (III) and PS in the Fe (III) / Fe (II) cycle when PS was captured by the HA-Fe-Mt system, and the in situ generated Fe accelerates the generation of reactive oxygen species (ROS) to further degrade TC. Consequently, HA can not only promote the adsorption of TC but also promote the degradation of TC in the Fe-Mt nano platform. HA-Fe-Mt provided a feasible and promising platform with PS activation for TC adsorption and degradation.