free energy and entropy. The results showed that the nanoparticle
adsorption was spontaneous and exothermic. Sheela et al. [13]
studied the adsorption of Cd (II) and Pb (II) on 28 nm-sized NiO
particles; the standard free energy, enthalpy and entropy calculations
indicated that the adsorption was endothermic and spontaneous.
Zhang et al. [14] determined that the adsorption of
selenium ions on 10–15 nm-sized TiO2 particles was exothermic