| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 608726 | Journal of Colloid and Interface Science | 2011 | 7 Pages |
FTIR-ATR kinetic studies on the adsorption of oxalic acid on different TiO2 films were performed. The particulate films were obtained through the evaporation of TiO2 suspensions. The evolution of the IR bands followed a pseudo-first-order behavior, as previously observed. Systematic studies as a function of the oxalic acid concentration afforded the specific rate constant for adsorption (ka) and desorption (kd). The influence of physical parameters of the samples, i.e., specific BET area, crystalline domain size, TiO2 load, film area, and pore size, on the kinetic parameters ka and kd was analyzed. A mechanism in which the adsorption and desorption processes are controlled by the diffusion through the pores of the films is proposed (intraparticle diffusion). It is concluded that all the samples behave in the same way. Thicker films or those with smaller particle size (higher specific surface area, smaller pores) show the slowest rates of adsorption and desorption. These results are relevant for the design of efficient heterogeneous catalysts and sensors, and for the interpretation of pollutant adsorption.
Graphical abstractFTIR-ATR studies for the adsorption of oxalic acid on different TiO2 samples were performed to evaluate the effect of film thickness, surface area, and particle size on kinetics and equilibrium.Figure optionsDownload full-size imageDownload high-quality image (73 K)Download as PowerPoint slideResearch highlights► FTIR-ATR spectroscopy studies on the equilibrium and kinetics of adsorption of oxalic acid on different TiO2 samples were performed. ► Surface complexes detected on the different samples display analogous spectroscopic characteristics and similar affinity toward TiO2. ► Adsorption and desorption kinetics are controlled by the diffusion within the pores of the films. ► The surface area of the films, TiO2 load, particle size, pore size, and film thickness strongly determine the kinetics of both adsorption and desorption. ► An analysis of the influence of the physical parameters on the kinetics is offered.
