Adsorption and Photocatalytic Properties of Surface-Modified TiO2 Nanoparticles for Methyl Orange Removal from Aqueous Solutions

Titanium dioxide nanoparticles surface-modified by 5-sulfosalicylic acid 5-SA-TiO2 were prepared in ethanol by the chemisorption process. The effects of surface improvement on the photocatalytic degradation and adsorption of methyl orange MO were studied in a batch system by considering the various parameters, such as contact time, adsorbent dosage, pH, initial dye concentration and temperature. The adsorption and photocatalytic degradation kinetics of MO using the improved nanoparticles have also been investigated. The results show that the adsorption and photocatalytic degradation processes were good fit with the pseudo-second-order kinetic model R2 0.99. In addition, the equilibrium data for the adsorption process have been evaluated using Langmuir, Freundlich and Temkin isotherms. The adsorption isotherm of MO onto modified TiO2 nanoparticles fitted into the Temkin equation.