Innovative technique for 4-chlorophenol desorption from granular activated carbon by low frequency ultrasound: Influence of operational parameters

In this work, the feasibility for the use of ultrasound as an innovative technique for the desorption of 4-chlorophenol (4-CP) from granular activated carbon (GAC) was investigated. Effects of operational parameters such as adsorbent dosage, adsorbent loading, ultrasonic power and temperature on the desorption kinetics were examined. The obtained results show that the amount of 4-CP desorbed decreased with the increase in adsorbent dose. The desorption gradually increased with increasing GAC loading, acoustic power and temperature. Better results were obtained with a multistage treatment process. The adsorbed molecules may be released into solution by breaking bonds and intensifying mass transfer phenomena through acoustic vortex microstreaming, shockwaves, microjets and thermal effects from cavitational collapse. For better understanding, desorption kinetic results were modeled using models with theoretical basis. Modeling of desorption kinetics shows that the second order surface kinetics seemed to play a more significant role than pore diffusion. (C) 2010 Elsevier Inc. All rights reserved.