Preparation of glucose-based N, P Co-doped carbon for non-radical pathway activation of PMS to degrade tetracycline hydrochloride

Abstract

A “1 + 1 > 2” effect was observed in non-metal doped carbon composites based on peroxymonosulfate (PMS) for advanced oxidation processes (AOPs). To overcome challenges such as the complexity of catalyst preparation in the current metal-free activated PMS process, in this study, nitrogen–phosphorus co-doped nonmetallic porous carbon-based catalysts (GMA) were prepared by a one-step pyrolysis method using glucose, melamine, and ammonium polyphosphate as raw materials for the efficient removal of tetracycline hydrochloride (HTC) by activated PMS. Various characterization methods were applied to study the morphology and physicochemical properties of GMA catalysts. The results showed that the system could remove up to 95% of HTC solution (20 mg L⁻¹) within 50 min, and the removal rate was still 90% after four cycles. The revelation indicates that GMA has excellent catalytic properties, excellent electron transfer rate, wide working pH range and good stability. The effects of inorganic anions, different water bodies and different pollutants on the GMA/PMS system were investigated to explore its practical applications. Further exploration showed that ¹O₂ was the key active species promoting HTC degradation in the GMA/PMS system; the intermediates were detected by LC-MS and three major degradation pathways were proposed. This study provides a new strategy of bi-heteroatom synergistic modulation for the design of metal-free catalysts, which promotes the practical application of persulfate advanced oxidation technology.