LAUSR

The adsorption characteristics of dissolved aniline onto powdered activated carbon (PAC) and the subsequent desorption by ultrasound treatment were studied. The results indicated that the adsorption followed the pseudo-second-order model and the Langmuir model. Acidic conditions were not conducive to the adsorption of aniline. The desorption efficiency of saturated PAC radiated by ultrasound reached a maximum of 24.35% with a sonication power of 180 W at a frequency of 40 kHz, and a pH of 3 within 180 min of sonication time. The addition of ethanol produced a synergistic effect with ultrasound, effectively improved the desorption efficiency to 83.88%. Intermediates of aniline that were formed during the ultrasound irradiation were analyzed by gas chromatography-mass spectrometry and this identified azobenzene as the main by-product. Analysis of the specific surface area, pore structure, and FTIR spectra of PAC indicated that more cavitation occurred in ethanol than in water, and high-speed microjets and high-pressure microstreams enlarged the mesopore of PAC. In general, the physical attack of microjets and microstreams played an active role in the desorption of aniline.