Dually organic modified bentonite with enhanced adsorption and desorption of tetracycline and ciprofloxacine

Tetracycline (TC) and ciprofloxacin (CIP) cause serious environmental and health issues upon their uncontrolled release to the aquatic system and hence their control required serious attention. In this study, adsorption and desorption performances of TC and CIP by sodium carboxymethylcellulose (CMC) and polyethyleneimine (PEI) modified magnetic bentonite (MBCP) were explored. It was found that active functional groups such as –COOH, –OH and –NH2 loaded on the surface of MBCP increased the selective adsorption performance of MBCP for TC and CIP. Meanwhile, MBCP had superior adsorption performance in a wide pH range, magnetic separation capability and good regeneration. Based on the adsorption kinetics, isotherm, pHPZC, FE–SEM, TEM, FT–IR, XRD, BET, XPS and VSM results, the mechanisms of MBCP adsorption and desorption were investigated which mainly involved electrostatic interaction, pores deposition, complexation and ions exchange phenomena. MBCP was realized higher adsorption capacity for TC (476 mg/g), and CIP (457 mg/g) than MB (300 and 270 mg/g, respectively). This study provides important reference information for the fabrication of MBCP as a novel and promising adsorbent for the remediation of antibiotics from wastewater on the industrial level.