The pollution of the waste water with phenol is a highly important environmental problem, because of its unfavourable consequences on the aquatic life, the organoleptic properties, and drinking water. The problem of the cleaning or recovery of the phenolic wastewater by new methods or trying to improve the existing ones is still a matter of concern of the environmental researchers [1]. Perovskite-type oxides are widely used in many fields. In particular, they can display prominent catalytic activities [2]. La0.7Sr0.3MnO3 nanoparticles were prepared by sonication- assisted copercipitation [3]. This catalyst was characterized by X-ray diffraction (XRD), transmisson electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR). The catalytic performance of the sample for phenol degradation was evaluated in the presence and in the absence of ultrasound. The effect of different parameters such as the pH, catalyst dosage, contact time, and temperature were considered for both methods. One of the important parameter is temperature which affects on the sonochemical process. The rate of degradation increased with increasing the temperature up to 30 °C, and then decreased at higher temperatures in contrast to the classical method. This behavior could be explained based on the cavitation process which produces milder conditions at higher temperatures.

Keywords