Optimizing ciprofloxacin removal using ion exchange resin: Exploring operational parameters and assessing toxicity

The present study investigates the adsorption behavior of ciprofloxacin hydrochloride (CIP) onto the cationic resin Amberlite IR120. Equilibrium and kinetic experiments were conducted to assess the influence of resin mass (0.02 to 0.19 g), agitation rate (200 to 500 rpm), pH (2 to 11), and temperature (15 to 45 C) on the efficiency of CIP removal. Non-linear models, coupled with error functions such as coefficient of determination (r2) and the sum of squared residuals (SQR), were employed to assess the compatibility between kinetic models (pseudo-first order, pseudo-second order, Elovich) and isotherm adsorption equations (Langmuir and Freundlich). The IR120 resin underwent characterization through scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), laser granulometry, nitrogen adsorption-desorption isotherms (BET), and attenuated total reflection infrared spectroscopy (ATR-FTIR). Utilizing the Langmuir model, the maximum adsorption capacity of CIP was determined to be 37 mg g(-1). Based on the r2 values obtained from the kinetic models, the pseudo-first order and pseudo-second order models exhibited the best fit for all experimental data. Optimal conditions for the adsorption occurred at pH 7, temperature of 15 C, resin mass of 0.08 g, and agitation rate at 300 rpm. Remarkably, complete elimination of toxicity towards Escherichia coli organisms was achieved, evidenced by the absence of antibacterial effects after 60 min of operation. Consequently, the results suggest that IR120 holds promising potential as an adsorbent for CIP removal.