Fast regeneration of activated carbons saturated with textile dyes: Textural, thermal and dielectric characterization

This study presents an investigation for comparing the regeneration process of two activated carbons saturated with Basic Blue 9 (BB9) and Acid Blue 93 (AB93) using conventional (250-500 degrees C) and microwave heating (100-300 W). The effect of the textile dye used on the regeneration performance was analyzed by determining their dielectric properties using the perturbation cavity method from 20 to 600 degrees C and by TG/DTG analysis. The efficacy of the regenerated carbons was investigated by their physical properties characterized by pore structural analysis using N-2 adsorption isotherms. Results showed only 3 min are required by microwaves to achieve similar textural parameters obtained by conventional heating at 190 min. The results indicate that the adsorbate plays a determining role on the regeneration efficiency as results of their interaction with the adsorbent, being easily regenerated when AB93 is the adsorbate. The adsorption capacity of microwave regenerated samples for AB93 and BB9 was 192-240 and 154-175 mg/g, respectively. Additionally, the equilibrium isotherms were simulated using the Langmuir and Freundlich isotherms models and the results suggest the textile dye removal is achieved on multilayer adsorption.