Sonocatalytic treatment of phosphonate containing industrial wastewater intensified using combined oxidation approaches

Treatment of actual industrial wastewater is a challenging task and has not been investigated using the cavitation-based approaches significantly. In the present work, sonocatalytic degradation (catalysts as CuO and TiO 2 ) of phosphonate based industrial wastewater, procured from a local company, has been studied in terms of COD reduction under optimized conditions (established using initial studies involving only ultrasound) of pH as 3.2, the temperature of 32 ± 2 °C and 120 min as treatment time. The combination of ultrasound with H 2 O 2 and ozone in different approaches has been investigated for maximizing the COD reduction. The optimum set of operating conditions for the sonocatalytic degradation were established as power dissipation of 90 W and catalyst loading as 0.75 g/L for CuO and 0.5 g/L for TiO 2 . Use of only ultrasound resulted in COD reduction of 37.2% whereas the combination of US with different approaches resulted in higher extents of COD reduction. The combined operation of US + H 2 O 2 + O 3 , US + O 3 + H 2 O 2 + CuO, and US + O 3 + H 2 O 2 + TiO 2 resulted in the extent of COD reduction as 91.5%, 93.8%, and 95.8% respectively. Overall, it has been clearly established that maximum COD reduction is obtained for the combined operation of sonocatalysis (catalyst as TiO 2 ) with ozone and H 2 O 2 .