Absorption behavior and mechanism of ciprofloxacin and tetracycline antibiotics on different rectorites

Abstract

Rectorite has a regular lamellar structure, and its structure tends to result in a high adsorption capacity. Prior research has examined the adsorption characteristics of rectorite on antibiotics by various analytical techniques, including X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The results demonstrated that the adsorption capacity of Na-Rec for both ciprofloxacin (CIP) (18.3 mg g⁻¹) and tetracycline (TC) (25.0 mg g⁻¹) was stronger than that of Ca-Rec for both CIP (17.7 mg g⁻¹)and TC (23.5 mg g⁻¹), and that both rectorites were stronger than CIP for TC (23.5 mg g⁻¹ > 17.7 mg g⁻¹, 25.0 mg g⁻¹ > 18.3 mg g⁻¹). Rectorites were characterized both before and after adsorption, and the effects of a number of variables on the adsorption process were investigated. During the adsorption process, ions are liberated in the interlayer structure and exchange with pollutant molecules in the interlayer. This study reveals that rectorites with different ionic hydrates states have distinct adsorption behaviors and loading capabilities, which is worthy of providing theoretical direction for future groundwater remediation including local stratigraphic mineral soils.