Activated peroxymonosulfate with co-doped copper oxide nanomaterials for highly efficient degradation of organic pollutants

Abstract

In the current work, a series of novel cobalt-doped copper oxide nanomaterials (Co-CuOT, subscript ‘T’ means ‘calcination temperature’) were prepared through the chemical reduction method following by calcination. Their reactivities were screened for the degradation of various organic pollutants including p-chlorophenol (4-CP) in the presence of peroxymonosulfate (PMS) as oxidant precursor. These as-prepared Co-CuOT nanomaterials possess exposed active surface as well as positive Cu-Co synergistic effect, and further enhances the 4-CP degradation by activating PMS. The Co-CuO300/PMS exhibited the best ability toward the 4-CP degradation, achieving 100% degradation of 4-CP and excess 80 % removal efficiency of total organic carbon (TOC) within 10 min at room temperature. The Co-CuO300 sample is two to thirteen folds dominative than the other samples (Co-CuO400, Co-CuO500, CuOcds and CoB), respectively. Attractive reactivities of Co-CuOT nano-catalysts are attributed to the amounts of oxygen vacancies, copper-cobalt synergy, and increased generation of reactive radicals. Based on quenching experiment and electron paramagnetic resonance (EPR) analysis, the degradation of 4-CP in the PMS/Co-CuO300 system was found to mainly depend on the species of free radicals, e. g., hydroxyl radical (•OH), sulfate radical (SO4•−). Meanwhile, Co-CuO300 displayed better recyclability and anti-interference ability. The reactivated catalyst after the fifth run still showed high degradation activity, even completely eliminating 4-CP. Substrate expense indicate that the Co-CuO300/PMS system exhibited high efficiency in the degradation of various types of organic pollutants including phenolic compounds and antibiotics under mild conditions. Phytotoxicity assessment showed that mung beans grew well in both the deionized water and the filtered degradation solution, suggesting highly remarkable elimination of 4-CP in Co-CuO300/PMS system. Overall, Co-CuOT nanocomposites hold great promise for large-scale practical application in the activation of PMS and subsequent degradation of organic pollutants.