Enhanced abatement of clarithromycin via hybrid adsorption and catalytic ozonation using cobalt-modified zeolite

The persistence of clarithromycin in water bodies poses significant environmental and public health risks due to antibiotic resistance development. Conventional treatments are often ineffective, while advanced oxidation processes like ozonation can be energy-intensive and generate byproducts. This study developed a cobalt-modified zeolite (Co-Z-3) catalyst via wet impregnation and calcination (300 °C, 3 h) for a hybrid adsorption-catalytic ozonation process. Characterization (Brunauer-Emmett-Teller analysis, scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction) confirmed successful cobalt incorporation, increased surface area (19.6 m2/g versus 13.8 m2/g for natural zeolite), and the presence of cobalt oxides phase. The main results show that cobalt-modified zeolite achieved 75% CLA adsorption in 45 min at 2.5 g/L dosage. The hybrid cobalt-modified zeolite achieved and ozone (Co-Z-3/O3) system achieved complete degradation of 74 mg/L clarithromycin in just 3 min, compared to 16 min for ozonation alone and 12 min for natural zeolite with ozone. The catalyst maintained >90% degradation efficiency over four reuse cycles, with adsorption capacity decreasing from 22.19 mg/g to 8.8 mg/g. Water quality analysis revealed partial mineralization (16.8% chemical oxygen demand reduction after 120 min) and enhanced biodegradability (five-day biochemical oxygen demand to chemical oxygen demand ratio increased from 0.099 to 0.169). Continuous-flow operation (reactor volume: 0.2 L; flow rate: 0.0234 L/min at 50 revolutions per minute) achieved complete removal at 8.5 min hydraulic retention time. The cobalt modification significantly enhances zeolite’s catalytic activity, the hybrid process enables rapid clarithromycin degradation, and the improved biodegradability suggests potential for coupling with biological treatment. This study presents a promising approach for macrolide antibiotic removal from water.