Integration of catalytic ozonation and adsorption processes for increased efficiency of textile wastewater treatment

Advanced and optimized textile wastewater treatment by catalytic ozonation and activated carbon (AC) adsorption was investigated. Scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy indicated that Mn and Ce oxides were successfully loaded on the γ-Al₂ O₃ support, and MnO₂ , Mn₂ O₃ , CeO₂ , and Ce₂ O₃ were the main components of the catalyst. Actual textile wastewater from biochemical effluent was used as experiment wastewater. The removal efficiencies of chemical oxygen demand (COD) and chromaticity were approximately 30.6% (414-287 mg/L on average) and 99.3% (4,033 times to 27 times on average), respectively during the 30-day on-site continuous-flow test with an ozone dosage, contact time, and gas-liquid ratio of 100 mg/L, 15.7 min, and 2.9, respectively. Following 1 g/L AC adsorption, the effluent COD concentration was reduced to 40 mg/L. By contrast, AC adsorption without catalytic ozonation as pretreatment required 10 g/L AC dosage to achieve similar treatment results. Gas chromatography-mass spectrometry analyses indicated that volatile phenols, sulfides, and aniline in wastewater were completely removed after treatment. Inductively coupled plasma results further showed that the active components of MnO_x -CeO_x in the catalyst were stable after continuous use for 60 days. PRACTITIONER POINTS: Mesoporous catalyst synthesized by impregnating MnO_x -CeO_x on γ-Al₂ O₃ support. Catalytic ozonation and AC adsorption were combined to degrade organics. Maximum degradation of COD and chromaticity by optimizing process variables. The efficiency of the method was compared to that of single AC adsorption.