Process optimization of spent catalyst regeneration under microwave and ultrasonic spray-assisted

In this work, the activated carbon loaded with zinc acetate dihydrate and used for catalyst in the polyvinyl alcohol and adhesive production process, was regenerated by microwave heating under ultrasonic spray atmosphere to recover the adsorption capacity of the spent catalyst. The effects of regeneration temperature, regeneration time and water mist flow rate on the adsorption ability of methylene blue (MB) and yield of activated carbon were researched systematically. The experiment results indicated that a promising adsorption capability via ultrasonic spray regeneration was developed for the spent catalyst, corresponding to Brunauer-Emmett-Teller (BET) surface area of 1263 m(2)/g and total pore volume of 1.28 mL/g under optimum conditions. The spent catalyst was also regenerated under the CO2 and N-2 atmosphere, which indicated that the better pore structure was obtained under ultrasonic spray conditions. The physico-chemical properties of the activated carbon were measured by N-2 adsorption, Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM). The results showed that the chemical groups of activated carbons changed after regeneration and before and the spent catalyst can be regenerated commendably by microwave and ultrasonic spray-assisted.