Catalytic Degradation of Acid Orange 7 Using CoFe₂O₄@Biochar Heterogeneous Catalytic Ozonation Process in Aqueous Solutions

The aim of this study is to propose a new catalyst for catalytic ozonation of acid orange 7 (AO7) dye in aqueous solutions. CoFe₂O₄@Biochar catalyst was synthesized, prepared, and used in a heterogeneous catalytic ozonation process (COP) for AO7 removal. The characteristics of synthetized nanoparticles were investigated through the following equipment: x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), fourier transform infrared (FTIR) spectroscopy, vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) and energy dispersive x-ray (EDX) analyses. The results showed that the process offered a sufficient efficiency for removal of 150 and 200 mg/L concentrations of AO7. Moreover, CO₃^2-, NO₃^-, Cl^- and PO₄^3- anions had a decreasing effect on the efficiency. The results of the scavenger experiments showed that the hydroxyl radical and ozone oxidants played the primary role for decomposition of the pollutants. The removal efficiency of total organic carbon (TOC) was 99% after 120 min by COP which was 44% more than the Single Ozonation Process (SOP). COP also caused the removal of chemical oxygen demand (COD) by 92% after 360 min. Based on the results, the COP with CoFe₂O₄@Biochar catalyst can be an effective and efficient process for treating textile wastewaters.