Adsorption kinetics of acid orange 7 on nano-CeO₂-TiO₂ in water

To investigate the application of nano-CeO₂-TiO₂ as a sorbent in wastewater treatment, CeO₂-TiO₂ powder was prepared by the solvothermal method and then characterized. The adsorption kinetics of the adsorption of acid orange 7 (AO7) on CeO₂-TiO₂ were investigated under various conditions, such as initial concentration, temperature, and pH of the AO7 solution. Kinetic analyses were conducted with both Lagergren pseudo-first and pseudo-second order models. The results showed that the CeO₂-TiO₂ powder was composed of cubic CeO₂ and anatase TiO₂ with a specific surface area of 140.42 m^-1 · g^-1. The adsorption capacity of AO7 on CeO₂-TiO₂ increased with increasing starting concentration of AO7, but decreased with increasing temperature. The most favorable pH range of the AO7 solution was 3-8 for the adsorption of AO7 on CeO₂-TiO₂. The results revealed that the adsorption kinetics of AO7 on CeO₂-TiO₂ matched the pseudo-second order model very well. The results indicate that CeO₂-TiO₂ has a potential application in the removal of AO7 from wastewater.