The beneficial effect shown by the sound is
probably due to the enhancement of the fluidization quality (which brings better
gas-solid contact and mass transfer coefficients) with respect to the tests
performed in ordinary conditions, namely without the aid of any external force. In
particular, the application of the sound greatly enhances the break-up
mechanism and re-aggregation of fluidizing aggregates (7,8), thus constantly
renewing the surface exposed to the fluid. In other words, the continuous
aggregates break-up and re-aggregation mechanism makes the surface of the
activated carbon more readily available for the adsorption process.