2011 Volume 44 Issue 10 Pages 774-780
Ultrasound irradiation and simultaneous gas bubbling into an aqueous solution of methylene blue has been studied in order to establish a cost-effective process for wastewater treatment. Various gases such as rare gases, oxygen, nitrogen, and carbon dioxide, as well as mixtures of argon and other gases have been used. The argon–oxygen mixture (70 : 30% v/v) gave the maximum degradation rate of ca. 45% after 30 min of treatment, and this was around 10% higher than that obtained with pure argon bubbling. Furthermore, the influence of the addition of a variety of metal oxide particles, including SiO2, TiO2, and Al2O3, has been examined. The degradation rate increased by 10%, to ca. 54%, by the addition of 2 g/L alumina for a treatment time of 30 min.