Ibuprofen degradation using a Co-doped carbon matrix derived from peat as a peroxymonosulphate activator

Abstract

The wider presence of pharmaceuticals and personal care products in nature is a major cause for concern in society. Among pharmaceuticals, the anti-inflammatory drug ibuprofen has commonly been found in aquatic and soil environments. We produced a Co-doped carbon matrix (Co-P 850) through the carbonization of Co2+ saturated peat and used it as a peroxymonosulphate activator to aid ibuprofen degradation. The properties of Co-P 850 were analysed using field emission scanning electron microscopy, energy filtered transmission electron microscopy and X-ray photoelectron spectroscopy. The characterization results showed that Co/Fe oxides were generated and tightly embedded into the carbon matrix after carbonization. The degradation results indicated that high temperature and slightly acidic to neutral conditions (pH = 5 to 7.5) promoted ibuprofen degradation efficiency in the Co-P 850/peroxymonosulphate system. Analysis showed that approx. 52% and 75% of the dissolved organic carbon was removed after two hours and five hours of reaction time, respectively. Furthermore, the existence of chloride and bicarbonate had adverse effects on the degradation of ibuprofen. Quenching experiments and electron paramagnetic resonance analysis confirmed that SO4·-, ·OH and O2·- radicals together contributed to the high ibuprofen degradation efficiency. In addition, we identified 13 degradation intermediate compounds and an ibuprofen degradation pathway by mass spectrometry analysis and quantum computing. Based on the results and methods presented in this study, we propose a novel way for the synthesis of a Co-doped catalyst from spent NaOH-treated peat and the efficient catalytic degradation of ibuprofen from contaminated water.