Adsorptive removal of antibiotics from water using magnetic ion exchange resin

The occurrence of antibiotics in the environment has recently raised serious concern regarding their potential threat to aquatic ecosystem and human health. In this study, the magnetic ion exchange (MIEX) resin was applied for removing three commonly-used antibiotics, sulfamethoxazole (SMX), tetracycline (TCN) and amoxicillin (AMX) from water. The results of batch experiments show that the maximum adsorption capacities on the MIEX resin for SMX, TCN and AMX were 789.32, 443.18 and 155.15 μg/mL at 25°C, respectively, which were 2–7 times that for the powdered activated carbon. The adsorption kinetics of antibiotics on the MIEX resin could be simulated by the pseudo-second-order model (R2 = 0.99), and the adsorption isotherm data were well described by the Langmuir model (R2 = 0.97). Solution pH exhibited a remarkable impact on the adsorption process and the absorbed concentrations of the tested antibiotics were obtained around the neutral pH. The MIEX resin could be easily regenerated by 2 mol/L NaCl solution and maintained high adsorption removal for the tested antibiotics after regeneration. Anion exchange mechanism mainly controlled the adsorption of antibiotic and the formation of hydrogen binding between the antibiotic and resin can also result in the increase of adsorption capacity. The high adsorption capacity, fast adsorption rate and prominent reusability make the MIEX resin a potential adsorbent in the application for removing antibiotics from water.