Obtaining and Properties of a Photocatalytic Composite Material of the “SiO2–TiO2” System Based on Various Types of Silica Raw Materials

Abstract

Compositions and technology for obtaining a photocatalytic composite material (PCM) by deposition of titanium dioxide particles synthesized by the sol–gel method on a silica support of various types (microsilica, gaize and diatomite) have been developed. The properties (chemical and mineral composition, dispersion, specific surface area, porosity, ζ-potential, acid–base properties, and microstructure) of microsilica, gaize and diatomite were studied to assess the effectiveness of using a photocatalytic agent as a carrier. In terms of specific viscosity (ηsp = 45), the concentration of the precursor (tetrabutoxytitanium—TBT) is set at 22 vol. % in a solvent (ethanol), at which it is possible to obtain the maximum amount of dissolved film oligomer without the formation of an aggregate-like precipitate. Modification of the reaction mixture (precursor: ethanol = 1:3) by replacing part of the solvent with a Span-60 surfactant/TBT = 1–1.1 made it possible to obtain polydisperse titanium dioxide particles with peak sizes of 43 nm and 690 nm according to laser granulometry data. Taking into account the interaction of titanium complexes with the surface of a silica support, a phenomenological model of the processes of structure formation of a photocatalytic composite material is proposed. By the value of the decomposition of rhodamine B, the photocatalytic activity of the developed composite materials was determined: PCM based on diatomite—86%; PCM based on microsilica—85%; PCM based on gaize—57%.

Microwave assisted sol–gel approach for Zr doped TiO2 as a benign photocatalyst for bismark brown red dye pollutant

“…After attaining the ideal concentration of catalyst, degradation slows as a result of an increase in turbidity of the solution and non-availability of dye molecules. 43…”

Multifunctional Anatase–Silica Photocatalytic Material for Cements and Concretes

“…In this regard, we assume that the increased functional characteristics of cement systems with photocatalysts are enabled due to the use of the anatase-silica photocatalytic material (ASPM), obtained by the sol-gel deposition of TiO 2 -sol onto diatomite (acting as a carrier) [20][21][22], in the case of the controlled degree of coating diatomite surfaces with nanoscale titanium dioxide.…”

A Study on the Cement Gel Formation Process during the Creation of Nanomodified High-Performance Concrete Based on Nanosilica

“…The modification of the following types of additives proved to be effective in improving the characteristics of cement composites: flask, diatomite [ 27 ], ultrafine quartz [ 28 ], nanomethakaolin [ 29 ], nanotitania [ 24 , 27 , 30 ], recycled aggregate [ 23 ], slaked lime [ 13 ], rice husk ash [ 31 ], nanosized cellulose filaments [ 32 ], nanofluid complex additive (graphene/PVA) [ 33 ], boron nanonitride, multilayer graphenes, zirconium oxide [ 24 ], nano-aluminum oxide [ 25 , 34 ], nanoclay [ 25 ], and iron and lead nano-oxides [ 35 ].…”

“…Modification with microsilica is currently very popular due to its effectiveness in improving the properties of concrete both separately and in combination with other additives [ 15 , 19 , 26 , 27 , 28 , 39 , 40 , 41 , 42 , 43 ]. The most effective dosages of microsilica vary from 5 to 20%, depending on the raw materials used and the types of concrete.…”

“…The most effective dosages of microsilica vary from 5 to 20%, depending on the raw materials used and the types of concrete. At the same time, the increase in strength characteristics varies from insignificant, when only microsilica is added, to quite impressive (30–80%), when other additives are used along with microsilica, in particular, flask and diatomite [ 27 ], fly ash [ 19 ], carbon nanotubes [ 26 ], nanosilica, and nanosilica sol [ 19 , 41 , 43 , 44 ]. Microsilica densifies and strengthens the structure, increasing its uniformity and stabilizing the cement hydration process [ 19 , 27 , 40 , 41 , 42 , 43 , 44 ].…”