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The constantly increasing growth in the number of cars is one of the reasons for the deterioration of the ecological situation in cities and large settlements. In Kazakhstan, on a national scale, the share of motor vehicles in total emissions of pollutants into the atmosphere by all technogenic sources reaches on average 40%, in the mass of industrial waste - 2%. The content of toxic substances in the exhaust of diesel and gasoline engines varies and depends on the type of engine and mode of operation, as well as on the quality of the fuel, the composition of the combustible mixture in the engine cylinders, speed and driving conditions, ignition system and fuel control. The number of all toxic components in the exhaust gas exceeds the maximum permissible standards by tens and hundreds of times. One of the most reliable ways to reduce the toxicity of vehicle exhaust gases and remove harmful substances is the complete oxidation of exhaust components using catalytic compositions on metal or ceramic block carriers. The article accumulates data from the scientific literature about toxicity of different components of exhaust gases and catalytic neutralization of vehicle exhaust gases by various scientific schools. [ABSTRACT FROM AUTHOR]

This research is devoted to solving an environmental problem, cleaning of the Kazakhstan air basin, through treatment of auto-transport toxic exhaust by improving the hydrocarbon composition of motor fuels and neutralizing exhaust gas toxic components. The catalytic hydrodearomatization of gasoline fractions (from the reforming stage) of the Atyrau and Pavlodar Refineries and the neutralization of exhaust gas toxic components from an internal combustion engine (ICE) were studied. Two hydrotreated gasoline fractions were tested during ICE operation. The research shows that 100% benzene conversion is observed over Rh-Pt(9:1)/γ-Al2O3 catalysts; that is, benzene is completely removed from both fractions, and the aromatics content decreases from 56.24–58.12% to 21.29–21.89%, within the values of the Euro-5,6 standard. Catalytic treatment of fuels reduces fuel consumption of the ICE engine by 2–3% compared to the initial gasoline fractions, the CO content in the exhaust gases decreases by 6.6–16.2%, and the hydrocarbon content decreases by 7.8–24.7%. In order to neutralize the ICE exhaust gas toxic components, the catalyst 10% Co + 0.5% Pt/Al2O3 was used, with which the CO conversion reaches 100% and the hydrocarbon conversion 94.2% and 91.5% for both gasoline fractions. The catalysts were characterized by electron microscopy (EM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), thermoprogrammed desorption (TPD) and thermoprogrammed reduction (TPR) methods. It was shown by the TPD and EM methods that at the addition of Pt to the Rh-catalyst, the formation of mixed bimetallic Rh-Pt-agglomerates occurs, and hydrogen appears in the TPD spectrum, adsorbed in the form of a new single peak uncharacteristic for the Rh-catalyst. This leads to high activity and selectivity in the hydrogenation of benzene and aromatic compounds in the gasoline fractions. The XRD and TPR results show the formation of CoAl2O4 spinels, on which inactive oxygen is formed for the oxidation of CO and hydrocarbons. Modification of the catalyst by Pt and Mg prevents spinel formation, thereby increasing the activity of the catalysts. [ABSTRACT FROM AUTHOR]