Heterogeneous Photocatalytic Oxidation of Pollutants in Air on TiO2 Particles

Mathematical Modeling of Heterogeneous Photocatalytic Mineralization of Organic Air Pollutants

“…Photocatalytic oxidation technology uses semiconductor nanoscale catalysts and UV radiation to mineralize airborne organic pollutants, i.e., transform them as the final products into the simplest inorganic compounds, in particular, water, carbon dioxide, or products such as sulfates, chlorides, and mineral acids [8,14]. In one of our previous works [15], we considered the process of the photocatalytic oxidation of some pollutants present in air on the surface of a semiconductor catalyst (TiO 2 ). In the course of integrating the kinetic equation describing the process of the photocatalytic destruction of the pollutants, the time dependence of the pollutant concentration in air was obtained in the form of an implicit function (logarithmic or exponential).…”

“…In this work, as in [15], we used the Langmuir-Hinshelwood model to study the kinetics of the monomolecular conversion of A molecules on active adsorption sites S on the catalyst surface under the action of UV radiation with the release of mineralized reaction products (MRPs), we used the Langmuir-Hinshelwood model ).…”

“…To analyze such an equation in our previous work [15], we switched to its exponential representation, modifying it with the approximation of a first-order two-exponential expansion and adding a number of correction factors to improve the accuracy of the description of the experimental data. However, further studies of this equation showed that there is a simpler method for describing the experimental dependences on its basis C A on t. The core of the proposed approach is that instead of searching using various approximations of the explicit function C A (t) to describe these dependences, an explicit functional dependence of t on C A should be used as an artificial technique.…”

“…If we assume that the rate-limiting stage of the two-step reaction (1) is the decomposition of the chemisorbed AS particles on the surface, and this is observed in most cases, then k r k -1 [15,16], and to determine constants K and k r of reaction (1), as follows from (14), it is possible to use a system of only two equations: (16) In this system, the number of equations is equal to the number of unknowns, and it can be used to calculate the values of the equilibrium constant K and rate constants k r of the decomposition reactions of the AS particles on the catalyst surface: (17) In the next section, using Eq. ( 13) with the parameters from (12), we will approximate both those taken from the literature and our own dependences obtained using the setup described by us earlier in [15]. Specific fitting options t c and m will be used whenever possible to calculate the equilibrium constants of reaction (1).…”

“…The new approach developed by us to analyze the experimental dependences of the concentration of pollutants in air on time, presented above, was applied to describe such dependences, both taken from scientific publications and obtained in the course of our own research. Some of these dependences (for dimethyl sulfide and acetone), experimentally measured in [18,19], we have already analyzed [15] in the approximation of a two-exponential expansion of the first order, and now such an analysis will be carried out using the approach described in the previous section.…”