Preparation of a self-cleaning glass using solutions of titanium fluor complexes

Abstract

The object of research is silicate glass with a nanostructured coating of titanium oxide (in the anatase modification), which is noted for photocatalytic activity and, as a result, acquires the ability to self-clean under ultraviolet irradiation. The existing industrial method of applying such a coating is carried out by the pyrolytic method, but it is effective for large-scale production, and is carried out for large-sized products from sheet float glass. For the production of small-scale, or piece products, it is not justified. This applies to products of complex configuration, and especially hollow. In the case there are methods of coating from the liquid phase. First of all, the sol-gel method. The classical such method requires titanium alkoxides, which are of high cost, as precursors. Cheaper and more flexible is the method of coating from solutions of titanium fluorine complex compounds. Ammonium hexafluorotitanate is used as a precursor, but it is expensive. It is proposed to modify the chain of chemical transformations, namely: to use the cheaper and more affordable ones as primary precursors. It is proposed to obtain it artificially, using the bifluoride method. During the study, ammonium bifluoride NH 4 HF 2 and titanium oxide TiO 2 are used, which, according to the proposed synthesis method, form (NH 4 ) 2 TiF 6 , its appearance is confirmed by X-ray phase analysis. Fluorination of titanium oxide Ammonium bifluoride occurred at a temperature not exceeding 200 °C. Fluorination is accompanied by the release of only water vapor and ammonia. A photocatalytic coating is obtained on float glass samples by precipitation of the anatase crystalline phase from an aqueous solution of (NH 4 ) 2 TiF 6 . The presence of anatase is confirmed by X-ray phase analysis. The size of crystalline formations does not exceed 15-20 nm. The self-cleaning ability is evaluated by the hydrophilicity test of the glass and the spectral characteristics of the coating in the ultraviolet range. Due to this, it is possible to obtain a self-cleaning coating on glass, which, in comparison with similar known ones, is not inferior in quality and has the following advantages: low cost and availability, absence of harmful emissions, complies with the principles of\xa0«green chemistry».