Design, preparation, characterization, and application of MnxCu1-xOy/γ-Al2O3 catalysts in ozonation to achieve simultaneous organic carbon and nitrogen removal in pyridine wastewater

Abstract

In the process of treating high-concentration pyridine wastewater, problems such as low treatment efficiency and total nitrogen (TN) residues are always encountered. Catalytic ozonation can degrade pyridine wastewater well, and it also has the potential to remove TN. However, limited research has been conducted on the development of ozonation catalysts that can simultaneously remove the total organic carbon (TOC) and TN. Density functional theory (DFT) technology can determine the number of active components on the catalyst based on its composition; therefore, it can be used to guide the research and development of such catalysts. Here, we presented a strategy to guide the preparation of two-component Mn and Cu catalysts using DFT technology. By characterising and applying the prepared MnxCu1-xOy/γ-Al2O3 catalysts, it was confirmed that the DFT accurately predicted the changes in the active site content. The selected catalyst also achieved strong TOC and TN removal rates during the catalytic ozonation of high-concentration pyridine wastewater. A Box-Behnken design and response surface methodology was used to optimise the process conditions of catalytic ozonation and verify its stability. Under the optimal reaction conditions, the TOC and TN removal efficiencies from a 500 mg/L pyridine solution were 99.8% and 45.8%, respectively. This work indicated that the use of DFT for the design of catalytic materials was an effective method, which can provide a theoretical basis for material design and reduce the time for material screening.