A. K. Pikaev

Use of tetrazolium salts in dosimetry of ionizing radiation

Abstract The paper summarizes the results obtained with participation of the authors from the study on the use of liquid and solid solutions of tetrazolium salts of different origin for dosimetry of ionizing radiation. The dosimetric systems based on the aerated solutions of some tetrazolium salts with nitro groups (for example, 2-(p-nitrophenyl)-3,5-diphenyltetrazolium chloride) in water-alcohol mixture which are suitable for measurement of doses from 1–5 to 50 Gy are described in detail. The application of poly(vinyl alcohol) films containing different tetrazolium salts for determination of doses from 0.5–25 kGy is considered thoroughly. The special attention was paid to the development of the films as color dose indicators with comparatively high stability to the action of day-light. It was achieved with the film containing 3,3′-bianisiline-4,4′-bis(2,5-diphenyl-2H-tetrazolium) chloride (blue tetrazolium).

Current status of the application of ionizing radiation to environmental protection: II. Wastewater and other liquid wastes (A review)

Present-day applications of ionizing radiation to environmental protection are surveyed. This part of the review summarizes new data on the radiation-chemical purification of municipal, industrial, and agricultural wastewater; liquid radioactive wastes; oils; etc.

Current status of the application of ionizing radiation to environmental protection: I. Ionizing radiation sources, natural and drinking water purification (A Review)

Present-day applications of ionizing radiation to environmental protection are surveyed. This part of the review summarizes new data on the ionizing radiation sources used in this area, on the radiation-chemical purification of polluted natural and drinking water, and on the mechanisms of processes occurring in these systems under exposure to ionizing radiation. A particular emphasis is placed on large-scale processes.

New data on electron-beam purification of wastewater

Recent environmental applications of radiation technology, developed in the authors laboratory, are presented in this paper. They are electron-beam and coagulation purification of molasses distillery slops from distillery-produced ethyl alcohol by fermentation of plant materials, electron-beam purification of wastewater from carboxylic acids (for example, formic acid) and removal of petroleum products (diesel fuel, motor oil and residual fuel oil) from water by γ-irradiation.

Electron-beam treatment of highly-coloured river water

Abstract The possibility of the application of electron beam for the purification of highly-coloured (40–150 degrees) water was studied. The object of the study was water from the Segezha River (Karelia, Russia) used for the supply of a small town of the same name. It was found that irradiation of this water by electron beam to the dose of 1–3 kGy led to the decrease in its colour to 20 degrees and even less. The required dose depends on the season when the water was taken for irradiation; it is higher for autumn and (partially) spring seasons than for winter and (partially) summer periods. It was also found that irradiation considerably accelerates the sedimentation of suspended particles and ensures the necessary disinfection of the water together with the conservation and even the improvement of its other parameters.

Combined electron-beam and adsorption purification of water from mercury and chromium using materials of vegetable origin as sorbents

Abstract Combined electron-beam and adsorption method of purification of water from Hg(II) and Cr(VI) using materials of vegetable origin as sorbents was developed. It consists in the addition of materials of vegetable origin (e.g. cellulose, carboxymethyl cellulose, starch, and wheat flour) into water, subsequent electron-beam irradiation, sedimentation and filtration of additives with captured Hg(II) or Cr(VI). The method is based on the synergistic effect of the combined action of irradiation and sorbent. The best results were obtained with the wheat flour. For example, the addition of 25 mg/I of the flour to the water containing 1 mg/I Hg(II) and irradiation with dose 1.1 kGy upon bubbling inert gas through the system led to the 98% removal of the pollutant. The possible mechanism of the processes causing the purification of water is discussed.

Combined electron-beam and ozone treatment of wastewater in the aerosol flow

Abstract Combined electron-beam and ozone method for purification and disinfection of wastewater in the aerosol flow is considered. The method consists in spraying the wastewater and subsequent electron-beam treatment of the produced aerosol flow in the presence of ozone. The results of the study on the purification of municipal wastewater by this method with using pilot plant based on low-energy electron accelerator (energy 0.3 MeV, maximum electron-beam power 15 kW) are described. The output of the plant is 500 m 3 /day. The data on economic feasibility of the method are presented.

New data of electron-beam treatment of municipal wastewater in the aerosol flow

Abstract New data on electron-beam treatment of municipal wastewater in the aerosol flow are presented. The effects of electron irradiation on various parameters (color, COD, BOD 5 , total number of microbes, odor, content of pollutants and so on) of municipal wastewater are considered. The special attention is paid to the radiation-induced decomposition of synthetic surfactants.

Contribution of Radiation Technology to Environmental Protection

The direct and indirect contributions of radiation technology to environmental protection are summarized. The indirect contribution consists in a considerably decreased or, in some cases, completely abandoned use of harmful substances (such as volatile organic solvents) in radiation-chemical processes, utilization of spent materials and products (in particular, butyl rubber), etc. The direct contribution includes the direct use of ionizing radiation for the purification and disinfection of polluted natural and drinking water, municipal and industrial wastewater, other liquid wastes, gas systems (for example, flue gases from thermal power stations), sewage sludge, and solid wastes (infected medical wastes, polluted soil, etc.); pest control (by radiation sterilization of male insects); etc. The corresponding examples based on recent studies are cited.

Current status of the application of ionizing radiation to environmental protection: III. Sewage sludge, gaseous and solid systems (A review)

Present-day applications of ionizing radiation to environmental protection are surveyed. This part of the review summarizes new data on the radiation treatment of sewage sludge and on the radiation-chemical purification of gaseous and solid systems.