ABSTRACT
A novel hydroxyl radical scavenging method was developed to establish the photocatalytic activity of TiO2 thin films. Transparent TiO2 thin films were prepared on soda-lime glass substrates using the sol-gel method and characterized using X-ray diffraction. During photoirradiation in aqueous buffered solutions, activity of the films was followed using the substituted nitrobenzene N,N'-(5-nitro-1,3-phenylene)bisglutaramide as a hydroxyl radical scavenger and its hydroxylated products were quantified using HPLC. The yield of hydroxyl radicals was evaluated at various pH of the reaction media, and reflected the dependence of the rate of the hydroxylation reaction on the experimental conditions and on the different qualities of the TiO2 thin films. The proposed method allows for direct assessment of hydroxyl radical production, it is straightforward and is proposed for routine use.
Subject(s)
Free Radical Scavengers/pharmacology , Hydroxyl Radical/analysis , Photochemistry/methods , Titanium/pharmacology , Catalysis , Chromatography, High Pressure Liquid , Hydrogen-Ion Concentration , Hydroxyl Radical/radiation effects , Phase Transition , Titanium/chemistry , X-Ray DiffractionABSTRACT
Sampling restrictions in analysis of cultural heritage materials narrow the choice of appropriate analytical methods considerably. In this work, near- and mid-FT-IR reflectance data were related to paper properties determined with classical analytical methods using partial least-squares. Nondestructive determination of properties, which are of importance for evaluation of the long-term stability of historical paper, i.e., ash content, lignin content, degree of polymerization of cellulose, pH, and aluminum content, is possible. With the use of a considerable sample set, satisfactory reliability was achieved for all properties but aluminum content. Considering that with age, chemical properties of paper change, dating of historical documents was attempted for the first time, also with success.
