Size-dependent Structural Properties of Anatase Nanoparticles on Adsorption Thermodynamic and Kinetic Characteristics of Acid Violet 43

The anatase nanoparticles with different particle size(5-10,25,40,60,and 100nm)and pore diameters(96,120,134,143,52),respectively were used as absorbents.The adsorption equilibrium and kinetic behavior of acid violet 43 onto TiO2 were investigated by a series of batch adsorption experiments.The adsorption process could be described by pseudo-second-order kinetic model and quasi first order kinetic model for particle sizes not more than 100nm,respectively.The adsorption rates were affected by the particle sizes of TiO2 and controlled by both intergranular diffusion and membrane diffusion.Adsorption isotherm could be fitted well with Langmuir equation.A remarkable positive correlation between the maximium absorption quantities(Qmax)and pore diameter was observed.When the particle size of TiO2was 60nm,its pore size was maximum,so its Qmaxwas the most as 104.17mg/g. The value of thermodynamic parameters,including △G0and 40kJ/mol △H 0,revealed that adsorption process was mainly physical adsorption with spontaneously endothermic character.