Oxidative degradation of pharmaceutical losartan potassium with N-doped hierarchical porous carbon and peroxymonosulfate

Losartan potassium (LOS) is a most globally consumed antihypertensive and emerging pharmaceutical contaminant of concern due to increasingly ubiquity in water and wastewater. For its effective environmental remediation, we propose the catalytic oxidation of losartan via peroxymonosulfate (PMS) activation using a metal-free N-doped hierarchically porous carbon (N-PC). We found out that N-PC exhibits both excellent adsorption capacity and catalytic oxidation efficiency with 100% LOS uptake within 240 min at 0.026 g/L of the N-PC. Fresh and used N-PC were scrutinized for textural properties and surface chemistry. The effects of PMS dose, temperature, pH, organic matter and coexisting anions on losartan decomposition were examined. Moreover, total organic removal was obtained and the catalyst was tested in three consecutive runs. Electron paramagnetic resonance and quenching assays revealed that the nonradical oxidation pathway plays a major role in LOS degradation by N-PC/PMS.