Spongelike porous CuO as an efficient peroxymonosulfate activator for degradation of Acid Orange 7

The morphology and structure of heterogeneous catalysts play crucial roles in peroxymonosulfate (PMS) activation by providing much more available active sites and high chemical stability. In this work, spongelike porous CuO (SP-CuO) was synthesized and used as a PMS activator to degrade Acid Orange 7 (AO7) from aqueous solution. The morphology and property of SP-CuO were characterized using various techniques. The results showed that nanoparticles of SP-CuO with uniform in size were agglomerated together to form a porous spongelike texture. In the catalytic experiments, SP-CuO showed highly effective in heterogeneous activation of PMS compared to commercial CuO and Co3O4. The first-order rate constant of SP-CuO was approximately 3.9 and 4.4 times greater than that of commercial CuO and Co3O4, respectively. The effects of experimental parameters including PMS dose, AO7 concentration, catalyst dosage, temperature and pH were systematically investigated. The highest degradation rate was achieved at pH 7.0. The activation energy of SP-CuO was obtained as 21.6 kJ mol−1. Sulfate radical (SO4−), mainly generated through heterogeneous reaction, was the dominant reactive species for AO7 degradation. Moreover, SP-CuO remained good activity and stability after being recycled five times, demonstrating its potential environmental application in the treatment of dye wastewater.