It can be observed that the values of the integral isosteric heat of desorption process of the damaged beans were higher than the values of the integral isosteric heat of adsorption
of the damaged beans; however, the values tend to a common equilibrium value at higher moisture contents (Figure 1).
Temkin adsorption isotherm assumes that the heat of adsorption
of all the molecules in the layer is inversely proportional to coverage of the adsorbent surface which might be attributed to adsorbate species - adsorbent interactions.
Where, ct the concentration of adsorbate at any time (mg L-1), co the concentration of BB3 at saturated solution (for this study, 10000 mg L-1), Xmax for BET, the maximum adsorption capacity (mg g-1), k for BET, a constant related with the heat of adsorption
The heat of adsorption
of water vapor in silica aerogel was assumed to be 50 kJ/kmol.
L] represent the maximum adsorption capacity for the solid phase loading and the energy constant related to the heat of adsorption
, respectively (Figure 4).
The Freundlich isotherm is derived by assuming a heterogeneous surface with a non-uniform distribution of heat of adsorption
over the surface , This isotherm is suitable for a highly heterogeneous surface.
Temkin isotherm [53, 54] includes the influences of indirect adsorbate/adsorbate interactions on adsorption isotherms and explains that because of these interactions the heat of adsorption
of all the molecules in the layer would decrease linearly with coverage.
Furthermore, the model is assuming that the heat of adsorption
97) of Freundlich adsorption revealed that the adsorption process is multi layered; with a non uniform distribution of heat of adsorption
L] indicates a binding constant which is related to the heat of adsorption
All the constants are specific to test conditions and the adsorbent type.
3] Heat of adsorption
774 Btu/lb or 1800 kJ/kg Iodine number 1180 Total pore volume 13.
Interestingly for benzene, a trend of slightly decreasing binding energy with increasing CNT diameter is seen for adsorption on internal sites and a much larger heat of adsorption