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

Abstract

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% (414-287mg/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 100mg/L, 15.7min, and 2.9, respectively. Following 1g/L AC adsorption, the effluent COD concentration was reduced to 40mg/L. By contrast, AC adsorption without catalytic ozonation as pretreatment required 10g/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 MnOx -CeOx in the catalyst were stable after continuous use for 60days. PRACTITIONER POINTS: Mesoporous catalyst synthesized by impregnating MnOx -CeOx 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.