Improved Self-Cleaning Properties of Photocatalytic Gypsum Plaster Enriched with Glass Fiber

Abstract

In the study the self-cleaning properties of photoactive gypsum plasters are presented. The modified gypsum plasters were obtained by addition of 1 and 3 wt.% of nitrogen-modified titanium dioxide (TiO2/N) and 0.1, 0.3, and 0.5 wt.% of glass fiber. The self-cleaning ability of the obtained materials was tested during two dyes decomposition: Methylene Blue (MB) and Reactive Orange (RO). It was found that presence of glass fiber increased photocatalytic activity of modified gypsum plasters, which may be due to the fact glass fiber may act as ducts for light and transport it to sites screened by TiO2 or glass fiber can retard charge recombination. Moreover, unexpectedly the addition of glass fiber did not increase the mechanical properties of modified gypsum plasters, which may be because gypsum does not strongly adhere to the surface of glass fibers.

Combined Effect of Photocatalyst, Superplasticizer, and Glass Fiber on the Photocatalytic Activity and Technical Parameters of Gypsum

“…Superplasticizing molecules can adsorb on the building materials grains in excess, which involves limited water access at the beginning of the hydration process [31]. Contrasting our previous results [11], in the current samples, the glass fiber induced the enhanced resistance of photocatalytic gypsum materials to mechanical forces. The only difference between the PG-SP2 and PG-SP2-F mortars is the presence of glass fiber in the second one.…”

“…The limited agglomeration of TiO 2 /N particles ensured higher accessibility to the active surface of the photocatalyst. It appeared that the effect of glass fiber in photocatalytic gypsum mortar was the same as it was reported previously [11], regardless of SP presence. The self-cleaning efficiency of PG-SP2-F toward RO degradation amounted to 51% within 40 h of UV irradiation, which was nearly 2 times higher than the correspondence results of PG plaster.…”

“…In the method, colors are expressed in the CIELAB system (ComissionInternationale de l'Eclairage), and hence the color space is defined by three different chromatic coordinates (L, a, and b) [43]. The procedure of colorimetric calculations was carried out on the basis of the literature report [44], and it was detailed described in our previous work [11].…”

“…The modification of the base structure of TiO 2 by a nitrogen element involved the visible response of the photocatalyst, which has been widely described in the literature [12,13]. Based on our previous studies [11], the glass fiber appeared to be effective for the transmission of the both sources of irradiation. Thereby, under UV as well as visible light, the degradation rate was higher, when the gypsum matrix apart from TiO 2 /N also glass fiber was used.…”

“…We reported in our previous research [11] that glass fiber is a very effective way to improve the self-cleaning properties of gypsum plaster. It was found that through simultaneously using photocatalyst particles and glass fiber in gypsum plaster, the photocatalytic activity was about two times higher than that of an adequate sample without glass fiber.…”