Ultrasound Accelerated Oxidation of Organic Dyes by a Micron-Sized Copper/Peroxomonosulfate System

Experiments on the degradation of acid orange 7 (AO7) using micron-sized zero-valent copper (ZVC) are conducted in acidic aqueous solution under ultrasonic (US) irradiation. The US/ZVC/peroxymonosulfate (PMS) process for AO7 degradation is significantly better than that of an independent system. Based on the characterization of ZVC, it is observed that the corrosion speed of ZVC increases after ultrasound, owing to which a greater amount of Cu + (0–3.03 mg L −1 ) and Cu 2+ are produced. Exposure to US irradiation increases the available surface area of the catalysts to generate many new reactive sites for the degradation process. The AO7 degradation rate after the addition of a new copper reagent—neocuproine hemihydrate—from 6.33% to 100% proved that Cu + is the main activator of PMS. Results indicated that free radicals (OH • and SO 4 −• ) act as activators of PMS in the process. And higher ultrasound power, lower solution pH, and a larger ZVC dose are favorable for AO7 removal.