Degradation of congo red induced by air-bubbles in the presence of nanometer TiO2 powders

Abstract

In this work, a new cavitation degradation method induced by air-bubbles passing small glass balls combined with TiO2 powders was provided to remove congo red (CG-R) in aqueous solution. And then the degradation process of CG-R was inspected by using UV–vis, total organic carbon analyzer, and high performance liquid chromatography technologies. The remarkably high degradation effect (about 98.89%) of CG-R can be obtained when the experimental conditions of 80 min air-bubbling time, 50 mg/L initial concentration, 1,000 mg/L anatase TiO2 amount, 3.0–3.5mm glass ball diameter, 4.50 L/min gas flow rate, and pH 6.0 solution acidity at 15.0 ± 0.2°C temperature were adopted. From the results it can be infered that there is a synergetic effect between air-bubbles passing small glass balls and TiO2 powders in the degradation of CG-R dyes. Moreover, the catalytic activity of nanometer anatase TiO2 powder was obviously higher than that of rutile TiO2 powder during the degradation of CG-R dyes. The degradation of CG-R induced by air-bubbles passing small glass balls combined with TiO2 powders follows the pseudo-first-order reaction kinetics. All experimental results indicate that this new method was a feasible and promising choice for the treatments of organic wastewaters.