Ultrasonic pre-treatment of an activated carbon powder in different solutions and influence on the ibuprofen adsorption

The aim of this work was to investigate the incidence of both ultrasounds at either low (20 kHz) or high (500 kHz) frequency and of processing solution [H2O2 (35%), UHQ water and HCOOH (98%)] on an activated carbon surface in relation with the adsorption properties of ibuprofen. Whereas samples sonicated at 20 kHz in H2O2 afforded reduction of particle size to submicrometric particles, sonication at 500 kHz, and whatever the solution preserved the original micrometric particles. The nitrogen adsorption-desorption isotherms of the raw and modified carbons were typical of microporous-mesoporous adsorbents. Surprisingly, almost no changes were observed in the surface chemistry after sonication in water or HCOOH at 500 kHz, whereas the same treatment at 20 kHz led to an oxidation of the surface. The sonication at 500 kHz was more effective at increasing the ibuprofen adsorption uptake than the sonication at 20 kHz.