Highly Efficient Ru Supported on Carbon Nanosphere Nanoparticles for Ciprofloxacin Removal: Effects of Operating Parameters, Degradation Pathways, and Kinetic Study

In this work, the capability of the catalytic wet air oxidation process (CWAO) using a ruthenium-carbon nanosphere catalyst (CNS-Ru) for the degradation of the widely spread antibiotic ciprofloxacin (CPF) has been investigated. The effect of the operating conditions on oxidative process, as well as different loads of ruthenium in the catalyst (1–10 wt %), reusability of the solid, reaction kinetics, and the pollutant degradation mechanism were investigated. The complete degradation of the pollutant was achieved at only 90 min reaction time within the following operation conditions: 140 °C, 20 bar, [CPF]0 = 20 mg·L–1, [CNS-Ru] = 0.67 g·L–1, 2 wt % of ruthenium, and initial pH 7.0. The catalyst was stable and could be successfully reused within three consecutive cycles with no loss of active phase. Two potential kinetic models were used for simulating the kinetic behavior of CPF in noncatalytic and catalytic processes. Finally, a degradation pathway involving 12 compounds was proposed.