In this study methylene blue (MB) has been investigated for its adsorption and subsequent catalytic
thermo-oxidative decomposition on surface of maghemite (c-Fe2O3) nanoparticles. The experimental
adsorption isotherm fit well to the Freundlich model, indicating multi-sites adsorption. Computational
modeling of the interaction between the MB molecule and c-Fe2O3 nanoparticle surface was carried
out to get more insights into its adsorption behavior. Adsorption energies of MB molecules on the surface
indicated that there are different adsorption sites on the surface of c-Fe2O3 confirming the findings
regarding the adsorption isotherm. The catalytic activity of the c-Fe2O3 nanoparticles toward MB
thermo-oxidative decomposition has been confirmed by subjecting the adsorbed MB to a thermo oxidation
process up to 600 C in a thermogravimetric analyzer. The experimental results showed a catalytic
activity for post adsorption oxidation. The oxidation kinetics were studied using the Ozawa–Flyn–Wall
(OFW) corrected method. The most probable mechanism functions were fifth and third orders for virgin
MB and MB adsorbed onto c-Fe2O3 nanoparticles, respectively. Moreover, the results of thermodynamic
transition state parameters, namely changes in Gibbs free energy of activation ðDGz
Þ, enthalpy of activation
ðDHz
Þ, and entropy of activation ðDSz
Þ, emphasized the catalytic activity of c-Fe2O3 nanoparticles
toward MB oxidation.