Surface modification of MXene using cationic CTAB surfactant for adsorptive elimination of cefazolin antibiotic from...

The increasing prevalence of pharmaceutical contaminants in aquatic ecosystems has raised significant environmental concerns, necessitating the development of efficient removal strategies. In this study, Ti₃C₂T_x MXene was synthesized and modified with cetyltrimethylammonium bromide (CTAB) to enhance its adsorption performance for cefazolin (CFZ), a widely used cephalosporin antibiotic. The structural and physicochemical properties of the modified MXene were comprehensively characterized using FESEM, EDS, FTIR, XRD, BET, and zeta potential analyses. Adsorption experiments were conducted under various operational conditions, including pH, contact time, adsorbent dosage, and initial CFZ concentration. The results revealed that CTAB modification significantly improved the adsorption capacity by increasing interlayer spacing and enhancing the accessibility of active adsorption sites. The optimized adsorbent (MC-0.9) exhibited a maximum CFZ removal efficiency of 96.3% and an adsorption capacity of 481.5 mg/g under optimal conditions: an adsorbent dosage of 0.1 g/L, a solution pH of 5, a contact time of 60 min, and an initial CFZ concentration of 50 mg/L. Kinetic and isotherm modeling indicated that the batch adsorption process followed the pseudo-second-order kinetic model and fitted well with the Langmuir isotherm, suggesting monolayer adsorption. Additionally, the presence of co-existing anions adversely affected adsorption efficiency, following the order CO₃^2- > Cl^- > SO₄^2- > NO₃^-. The adsorption mechanism was primarily governed by electrostatic interactions, π-cation interactions, and hydrogen bonding. Furthermore, the CTAB-modified MXene demonstrated robust recyclability, maintaining high efficiency over four consecutive cycles, highlighting its potential as a promising adsorbent for the removal of pharmaceutical pollutants from wastewater.