Treatment of Textile Wastewater by a Novel Clay/TiO₂/ZnO-Based Catalyst, Applying a Synergic Catalytic Ozonation–Electroflocculation Process

Abstract

This study aims to investigate the treatment of real textile wastewater using a novel bentonite clay/TiO2/ZnO-based ozonation catalyst. In this study, synergic electroflocculation/catalytic ozonation, catalytic ozonation, and ozonation processes are applied in a modified hybrid reactor. To the authors’ knowledge, this is the first application of bentonite clay/TiO2/ZnO as an ozonation catalyst for treating real textile wastewater. The four operational variables—ozone dose (0.2–0.8 mg/min), reaction time (0–120 min), DC voltage supply (5–15 V), and catalyst dose (0.5–2 g/L)—were studied for decolorization and for the removal of chemical oxygen demand (COD). The results showed that the combined process (electroflocculation + clay/TiO2/ZnO/O3) had the highest removal efficiencies for COD and color (97.86% and 97.90%, respectively) at optimum parameters of 10 DC volts. an ozone dose of 0.8 mg/min, and a catalyst dose of 2 g/L in textile wastewater. The results further revealed that the initial pH of wastewater plays an essential role in the process’s overall performance. The studied synergic process was efficient for real wastewater treatment under alkaline pH (6–9). Based on empirical work, we established that the synergic process is suitable for effectively treating textile wastewater.

Keywords

• catalytic ozonation
• electroflocculation
• decolorization
• COD
• textile wastewater