Nitrogen-doped porous carbon derived from graphite of solid waste for activating peroxymonosulfate to degradation tetracycline

Abstract

Nitrogen-doped porous carbon material based on graphite of solid waste and urea was prepared by mixing and pyrolysis method, the performance and mechanism of the prepared materials as catalysts to activate peroxymonosulfate (PMS) for ctetracycline (TC) degradation were investigated. Results indicated that addition of urea and sodium bicarbonate (NaHCO3) effectively enhanced the degradation of TC. When the mass ratio of graphite/urea/NaHCO3 and pyrolysis temperature was 1: 2: 2 and 800 °C, respectively, the obtained catalyst had optimal performance for activating PMS to TC degradation. The degradation efficiency of TC reached 99.8% within 30 min under the conditions of 0.10 g/L catalyst, 0.20 g/L PMS and 20 mg/L TC solution. Results suggested that the catalyst had well catalytic repeatability, versatility and adaptability under different conditions. The radical quenching test, electrochemistry experiment and electron paramagnetic resonance (EPR) measurements suggested that superoxide radical (O2•-) and singlet oxygen (1O2) plays dominant roles in TC degradation. XPS indicated that pyridine N, graphite N and functional groups of CO and –COOH were the potential active sites for PMS activation. This provides new insights for the recycling of solid waste and preparation of high-performance carbon based catalysts for wastewater treatment via Fenton-like process.