3.5. Thermodynamic parameters
The free energy of adsorptionwas calculated by Eq. (4) where
“K” is the adsorption coefficient obtained from the Langmuir
equation [33]. The values of free energy are negative for all the
system as shown in Table 4, indicating that the process is spontaneous.
TheGvalues for all the cases more or less approximatly
remains constant, indicating that there is no effect of temperature
on free energy of adsorption.
The heat of adsorption was calculated using Eq. (5) by plotting
a graph of ln K versus reciprocal of temperature as shown
in Fig. 14. The slope gave the value of heat of adsorption
shown in Table 3. The values of H for all the systems are
negative, indicating that the processes are exothermic. The sim