Activation, regeneration and recycling of spent catalyst using ultrasonic impact

The paper analyzes studies on the activation, regeneration and recycling of spent catalysts using ultrasound exposure. The study showed that ultrasonic treatment (22–44 kHz, up to 13 W/cm2, up to 2 kW) of spent catalysts really allows for their activation and regeneration, by removing surface deposits, films, and dispersing catalyst particles. Comparison of methods using ultrasound with traditional methods of catalyst cleaning showed a significant reduction in process duration, an increase in the degree of cleaning, and the cost-effectiveness of recovery. The effects of using ultrasound - cavitation, radiation pressure, acoustic flows with frequencies of 20–22, 30, 35, 37, 80 kHz, intensities up to 10 W/cm2 in the process of acid, bacterial-chemical leaching of spent catalysts, due to the destruction of oxide films and contaminants, removal of surface deposits, intensification of diffusion of the leaching solution into microcracks, significantly accelerates the process – up to 30 %, increases the percentage of extraction of target metals – up to 99.9 %.