Determination of the photocatalytic activity of TiO2 coatings on clay roofing tile substrates methylene blue as model pollutant

Abstract

The photocatalytically active mesoporous coatings, based on titanium dioxide sols (Degussa), of the fired clay roofing tiles substrate were prepared by using poly(ethylene glycol) (PEG) M-600 and M-4000, as the structure directing agents. The coatings were deposited using spray technique followed by thermal treatment. Photocatalytic activity of the TiO2 coatings was evaluated by aqueous solution of methylene blue as model dye, deposited on the top of the coatings, after irradiation with UV light. The results were compared with the photocatalytic efficiency of some commercial self-cleaning products (clay roofing tiles, glass). The newly design coatings showed an interesting decolourisation performance (over 30 % after 24 h). It appeared that the procedure of photocatalytic activity determination, in the case of porous substrates, should be renewed by a preadsorption process.Fotokataliticki aktivne mezoporozne prevlake nanete na povrsinu glinenog crepa napravljene su od sola titanijum dioksida (Degussa, Germany) i poli(etilen glikola-PEG) M-600 i M-4000 koji je nosilac mezoporozne strukture. Prevlaka je naneta koriscenjem sprej tehnike i termickog tretmana. Fotokataliticka aktivnost TiO2 prevlaka je procenjena koriscenjem metlen plavog kao model boje, postavljene na prevlaku, nakon zracenja UV zracima. Rezultati su poredjeni sa rezultatima fotokataliticke aktivnosti nekih komercijalnih proizvoda (glineni crep, staklo). Novoformirana prevlaka je pokazala znacajan nivo obezbojavanja rastvora (preko 30% posle 24h). Ustanovljeno je da postupak odredjivanja fotokataliticke aktivnosti za slucaj poroznog crepa bi trebalo da bude inoviran uvodjenjem procesa predadsorpcije.