[Degradation of Ciprofloxacin by Activating Peroxymonosulfate with Sludge Biochar].

Sludge biochar(BC), which was prepared by the pyrolysis of waste-activated sludge at 450℃, was applied for peroxymonosulfate(PMS) activation to construct a BC/PMS system for ciprofloxacin(CIP) degradation. The physical and chemical properties of BC were studied using scanning electron microscopy(SEM), an energy dispersive spectrometer(EDS), a Fourier transform infrared spectrometer(FTIR), X-ray diffraction(XRD), a Zeta potential analyzer, and electron paramagnetic resonance spectroscopy(EPR). The effects of BC dosage, PMS dosage, initial pH value, and inorganic anions on CIP removal in the BC/PMS system were investigated. Further, the degradation mechanism of the BC/PMS system was speculated through the free radical quenching experiment and X-ray photoelectron spectroscopy(XPS) analysis. The results showed that the CIP degradation rate was 49.09% at a BC dosage of 1.0 g·L, PMS of 3.0 mmol·L, CIP of 20 mg·L, and pH of 6.0 in 120 min. SO and NO had no obvious effect on the removal of CIP in the BC/PMS system, whereas HCO and Clcould inhibit CIP degradation significantly. The CIP removal in the BC/PMS system was attributed to the common function of the radical pathway dominated by ·OH and SO· and the non-radical pathway dominated by O. The CIP degradation pathway mainly included piperazine ring opening and hydroxylation reaction.