Heterogeneous co-activation of peroxymonosulfate by CuCoFe calcined layered double hydroxides and ultraviolet irradiation for the efficient removal of p-nitrophenol

Advanced oxidation processes by the activation of peroxymonosulfate (PMS) have been widely concerned for the enhanced degradation of organic pollutants. In this work, CuCoFe calcined layered double hydroxides (CuCoFe-CLDH) were successfully prepared via a simple method, and its lamellar structure and spinel-like composites were proved by using XRD, SEM and FT-IR. The CuCoFe-CLDH was used to activate PMS to produce many active species for the degradation of p-nitrophenol (PNP) under ultraviolet irradiation (UV). At the optimal conditions of CuCoFe-CLDH dosage 0.3 g/L and PMS dosage 0.3 g/L, it was discovered that the degradation efficiency of 20 mg/L PNP was about 95.11% under UV light within 30 min. In addition, the degraded reaction accorded with the pseudo-first-order kinetic behaviors, and it was found that SO4 center dot- and center dot OH radicals were effective active species in the quenching experiments under the CuCoFe-CLDH/UV/PMS system. The CuCoFe-CLDH could still keep above 93% after five continuous recycles, and also showed remarkable reusability and stability in accord with the characterization analysis of fresh and used materials. Briefly, this work could be a promising method for the treatment of the phenol-bearing wastewater and support theoretical foundation for PMS activation.