Microwave-assisted method to degrade phenol using persulfate or hydrogen peroxide catalyzed by Cu-bearing silicon carbide

• Published in: Water science and technology 2020-08, Vol.82 (4), p.704-714
• Main Authors: Sun, Jie, Xia, Guotong, Yang, Wenjin, Hu, Yue, Shen, Weibo
• Format: Article
• Language: English
• Subjects: Analytical methods; Carbon Compounds, Inorganic; Carboxylic acids; Catalysis; Catalysts; Chemical oxygen demand; Copper; Decomposition; Degradation; Electron transfer; Experiments; High performance liquid chromatography; HPLC; Hydrogen; Hydrogen Peroxide; Hydroxylation; Irradiation; Kinetics; Liquid chromatography; Microwave radiation; Microwaves; Nitrates; Organic carbon; Oxidation; Oxidation-Reduction; Oxidoreductions; Phenol; Phenols; Photoelectron spectroscopy; Photoelectrons; Pollutants; Polymer matrix composites; Reagents; Scanning electron microscopy; Silicon; Silicon carbide; Silicon Compounds; Sodium; Sodium persulfate; Spectrum analysis; Synergistic effect; Temperature effects; Total organic carbon; X ray photoelectron spectroscopy
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2020.370

The radical generation properties of hydrogen peroxide and persulfate for phenol degradation were investigated under microwave irradiation using copper-doped silicon carbide (Cu/SiC) composites as catalyst. The results showed that 90% and 70% of phenol and total organic carbon (TOC), respectively, were removed within 7 min. Microwave activation of hydrogen peroxide and sodium persulfate in terms of thermal effects and accelerated electron transfer was analyzed by degradation kinetics and X-ray photoelectron spectroscopy (XPS). The microwave activation of Na S O demonstrated that the hot spots promote decomposition of persulfate more rapidly and the rate of persulfate decomposition was more than three times the activation rate of a normal heating method. There is a synergistic effect between Cu and microwave radiation, which is highlighted by the H O activation; ·OH was generated due to the redox cycle between Cu(I)/Cu(II) and was responsible for phenol degradation using H O . High performance liquid chromatography (HPLC) analysis indicated that hydroxylation and sulfate radicals addition of phenol were the initial oxidation reaction steps of hydrogen peroxide and persulfate, respectively, followed by further oxidation to form short-chain carboxylic acids.