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The most comprehensive kinetic model for the gas-phase radiation-chemical degradation of polycyclic aromatic hydrocarbons is proposed on the basis of analysis of published data, which takes into account both the radical and ion-molecule mechanisms of the process. The model was verified by comparing the calculation results with the experimental data. It was shown that the efficiency of the process is lower in dry gas mixtures in which the ion-molecule mechanism plays the principal role in the degradation of aromatic molecules than in wet mixtures in which the radical mechanism dominates.

A kinetic model for the gas-phase radiation-chemical oxidation of naphthalene was developed on the basis of published data. The principal routes of naphthalene conversion were studied with the use of the model. It was shown that the main product of naphthalene radiolysis under the electron-beam dry scrubbing (EBDS) conditions of the removal of NO and SO2 from industrial gases is nitronaphthalene. The results of numerical simulation are compared with the experimental data.

The gas-phase radiation-chemical formation of dioxins from chlorinated phenols in the electron-beam removal of toxic impurities from industrial gases is considered. A kinetic model of the process is proposed. Conditions under which the efficiency of removal of the above compounds from gases significantly decreases were determined with the use of this model. The results of a numerical simulation are compared with currently available experimental data.

The feasibility of formation of peroxyacetyl nitrates and aromatic nitro compounds in the electron-beam removal of sulfur oxides and nitrogen oxides from the combustion products of organic fuels was studied. A kinetic model of the process was proposed. According to this model, the concentration of the resulting peroxyacetyl nitrates is comparable to the initial concentration of aliphatic hydrocarbons. The degradation of aromatic molecules is accompanied by nitration; in this case, both of the processes occur at approximately equal rates.

The effectiveness of the electron-beam removal of harmful impurities from gases was studied as applied to polycyclic aromatic hydrocarbons. A kinetic model of the process was constructed for the formation and degradation of aromatic molecules under the action of ionizing radiation in high-temperature (T>400 K) and low-temperature (T≤350 K) regions. Conditions under which the concentrations of the test compounds were effectively decreased were found with the use of this model.

Possible mechanisms of the photochemical conversion of polycyclic aromatic and nitroaromatic hydrocarbons in the urban atmosphere under the action of sunlight were analyzed. A kinetic model of the process was proposed, which takes into account the emission of harmful substances and the deposition of these substances onto the Earth's surface. It was found that emission is a predominant process within the bounds of a city. Beyond the precincts of a city, the concentrations of these hydrocarbons decrease because of photochemical degradation. In this case, the rate of this process for compounds adsorbed by soot particles is much higher than the corresponding value for compounds that occur in the gas phase. The results of calculations were compared with measurement data.

The process of ozone formation in an oxygen-containing gas atmosphere by the action of ionizing radiation was studied. A kinetic model of the process was constructed for the O2–N2 system. The effects of the main parameters of radiolysis on the O3 formation rate were analyzed. The atmospheric emission of ozone from industrial-scale power units that employ electron-beam flue gas cleaning of harmful impurities was evaluated from the standpoint of its conceivable favorable effect on the Earth ozone layer.

The efficiency of the electron-beam treatment of gases for the removal of sulfur and nitrogen oxides was examined as applied to dioxins. The gas-phase and liquid-phase degradation of dioxins and the oxidation of condensed carbon to form dioxins were taken into account in a model for the behavior of dioxins under the action of ionizing radiation. It was found that the formation of dioxins can significantly decrease the removal efficiency. Under certain conditions, the initial concentration of dioxins can increase.

The behavior of a hydrogen–air mixture under the action of ionizing radiation was studied. A kinetic model for radiation-chemical processes in the H2–O2–N2 system was constructed, and the effects of the main parameters of radiolysis on shifting its flammability limits were analyzed. It was found that, under normal conditions (p = 0.1 MPa, T0 = 300 K), the ignition of the stoichiometric mixture began at a radiation intensity of about 0.1 kGy/s. The induction period of the chain H2 oxidation reaction shortened with increasing radiation dose rate and pressure.

The effect of HCl on the conversion of mercury vapor in the electron-beam treatment of power-plant flue gases for removing nitrogen and sulfur oxides was investigated. A kinetic scheme for the process consists of the liquid-phase oxidation of Hg by O3molecules and OH radicals followed by the adsorption of liquid-phase oxidation products on soot particles, which are removed from the gas flow using filters. It was found that almost complete removal of mercury vapor is attained at typical radiation doses and process temperatures at soot concentrations higher than 100 μg/m3(STP). At a soot concentration lower than 100 μg/m3(STP) and an HCl concentration higher than 50 mg/m3(STP) in the gas phase, biologically active HgCl2is formed in considerable amounts.

The efficiency of the electron-beam treatment of power-plant flue gases for the removal of sulfur and nitrogen oxides was examined as applied to the removal of dioxins from the gases. A kinetic scheme of the process was proposed. It involves gas-phase and liquid-phase degradation of dioxin molecules by OH radicals formed under the action of ionizing radiation on gas macrocomponents. It was found that gas toxicity due to dioxins decreased by an order of magnitude at radiation doses typical of the method.

The efficiency of radiation-chemical treatment of flue gases from thermal power stations for removing nitrogen and sulfur oxides was examined as applied to the removal of mercury vapor from the gases. A kinetic scheme of the process was developed. It involves the liquid-phase oxidation of Hg by O3 molecules formed under the action of ionizing radiation on the gas macrocomponents followed by adsorption of the oxidation products at soot particles. It was found that almost complete removal of mercury vapor is attained at typical radiation doses and soot concentrations in the flue gases.