Investigations On The Adsorption Of Methylene Blue On TiO₂ Thin Film And Its Applications Using Slab Optical Waveguide Technique

In this paper,the adsorption and catalytic degradation behaviors of methylene blue on titanium dioxide(TiO2)thin film are preliminarily investigated with the slab optical waveguide(SOWG)spectroscopy technique.Based on the improvement of H2O2 in the catalytic degradation of TiO2 thin film towards methylene blue,a simple method for the sensing of H2O2 is thus developed.The main content of this paper includes the following three parts.In the first part of this paper,a simple introduction is given to the overview and principle of SOWG technique.At the same time,the methodologies used for the preparation of waveguide film in SOWG and the applications of SOWG technique in the field of analytical chemistry are summarized.In the second part,the SOWG platform is established by using a piece of cover glass as the waveguide support.The stability of this SOWG system is investigated by using methylene blue as the aimed analyte.Some parameters related to the performance of SOWG system,such as the length of sample cell and the angle of reflected light are optimized.In the third part,a TiO2 thin film is firstly modified onto the surface of cover glass via sol-gel method.Based on the evanescent wave,the adsorption and catalytic degradation behaviors of methylene blue on the TiO2 thin film are investigated by the TiO2 thin film modified cover glass as the waveguide support in SOWG system.The parameters in the preparation of TiO2 thin film and adsorption procedure are studied,and the concentration of TiO2 sol 3.0 mg L-1 is adopted for ensuing studies.The results of adsorption/catalytic degradation recycles indicate that the TiO2 thin film modified onto the surface of cover glass could be used repeatedly.This developed SOWG system could be readily used for monitoring the dynamic catalytic degradation of methylene blue by TiO2 thin film.According to the improvement of H2O2 on the catalytic degradation performance,a simple method for the detection of H2O2 content is developed,with a linear range of 0.1?0.75 mol L-1.This developed detection method could be used in a sample pH range of 5?9.