STATISTICAL PHYSICAL MODELING TO UNVEIL THE ADSORPTION MECHANISM OF MANGANESE ION ON MODIFIED SURFACE OF PORPHYRIN

In this study, the adsorption mechanism of manganese ions onto the 5, 10, 15, 20-Tetrakis(4-tolylphenyl) porphyrin molecule (H2TTPP) was studied and interpreted. Through the spin coating method, a thin film of H2TTPP was deposited and so the adsorption isotherms of Mn2+ ions on a thin H2TTPP layer were measured using quartz crystal microbalance technique (QCM). These isotherms were modeled using the statistical physics approach. The mechanism of the adsorption was elucidated by essentially three physicochemical parameters such as: the quantity of attached ion to each receptor site, the number of accessible receptor sites, and the concentration at half saturations. The simulation results provide that H2TTPP is linked to more than one manganese ion, with an adsorption energy of less than 40kJ/mol which implies a physical adsorption process. The statistical model is useful to characterize the adsorbent-adsorbate system. Hence, three thermodynamic functions are calculated and interpreted. Then, distributions of the pore size (PSD) and the adsorption energy (AED) were also deduced.