Investigation of synthesis and sonocatalytic performance of activated carbon-supported catalysis systems

The main aim of this study was to investigate the effectiveness of the sonocatalytic systems for the catalytic treatment of Olive Mill Wastewater (OMW) effluent streams. For this purpose, four different types of activated carbon-supported catalysts (TiO₂/AC, V₂O₅/TiO₂/AC, WO₃/TiO₂/AC, and V₂O₅/WO₃/TiO₂/AC) were synthesized by sol–gel method. The sonocatalysts were characterized by using TEM, SEM, XRD characterization techniques, and BET analyses. The performance of these novel catalytic systems was investigated by conducting experiments to remove various types of polluting components from OMW such as color, lignin, and chemical oxygen demand (COD). Preliminary experiments were conducted to evaluate the effects of various parameters such as reaction time, catalyst type, amount (as solid/liquid ratio), ultrasound amplitude, and initial pH values for process optimization. In the preliminary studies, it has been observed that there was no change in the percentage removal of the abovementioned polluting components. In the second set of experiments, hydrogen peroxide (H₂O₂) was used as the oxidizing agent. The results showed that the V₂O₅/TiO₂/AC catalyst was much better than the remaining catalysts in the removal of color, lignin, and COD from OMW effluent streams. In addition, when this method was used, it was observed that lignin was removed significantly (60%), but an increase in phenol concentration was observed (40%). It was observed that high efficiency was obtained under experimental conditions of V₂O₅/TiO₂/AC catalyst, catalyst amount: 1.0 gL⁻¹, time: 90 min, 1 mLL⁻¹ H₂O₂, 60% amplitude, and natural pH. In addition, it was observed that the removal was higher as the amplitude ratio increased and pH values were lower. It can be said that the sonocatalytic process may be more effective at the beginning, and the efficiency increase may be higher when integrated with the other processes.