Pikula L.F., Kruyk T.V.

Ukraine, Donetsk National University of Economics and Trade named Mikhail Tugan-Baranovsky (DonNUET)

ENVIRONMENTAL ASPECTS IN THE STUDENT’S

RESEARCH WORKS

One of the components of higher education is attracting students to scientific work, which can be not only directed toward the solution of specific production problems, but also larger scale environmental problems particularly concerning the Ukraine. This work is helping to form the student's motivation to study, activates of their further cognitive activity and contributes to the formation of highly qualified specialists. We give particular attention to environmental aspects for our students when forming themes for scientific work.

As a result of long irrational human economic activities, the natural resources of the planet have been seriously depleted, water and air space polluted and industrial and domestic wastes are accumulated in ever increasing volumes. Today Ukraine is considered one of the most environmentally disadvantaged countries in Europe. Therefore the topics devoted to the decision of integrated problems are particularly relevant and interesting for students. On the one hand this is the problem - to protect the environment and purify it from existing and further future contamination, on the other side - the problems of resource conservation and expansion of resource bases of the country. In this regard, over the past few years at the chair of chemistry of DonNUET there is a student’s scientific society, the work of which aims to address such problems. We offer not only to monitor the degree of contamination of water and land resources, but are also looking for various ways of waste conversion with the purpose of their utilization, recycling and creating bases of new and raw materials.

Environmental aspects are addressed in the study of all chemical courses for various specialties. For example, at the Faculty of Restaurant and Hotel's Business students learn the disciplines of: "Analytical Chemistry”, “Physical and Colloid Chemistry” and "Methods for food control”. Students of the Faculty of Marketing, Merchandising and Customs are studying the discipline of: “Chemistry and methods of investigation of raw materials and materials". These disciplines provide not only the theoretical foundations of physical and chemical methods of research, but also the skills of experimental work.

The object of research in the curriculums of chemistry can be investigation of the sewage and commercial wastewater containing a significant number of different harmful substances (radio nuclides, heavy metals, phenols, petroleum products, etc.). It is known that environmental risks arise from sewage not only from heavy industry but also from the food industry. Therefore, students have analyzed the chemical composition of water discharged from a confectionery factory in Donetsk in one of their studies. Students made conclusions about the nature and extent of pollution of wastewater of this plant depending on the type of production, raw materials used and the resulting manufactured products.

The pH of wastewater at this factory as a rule do not conform with the regulatory indices - there is high acidity or alkalinity. This is because the production of confectionery is using various substances as preservatives and food additives. Some of the more widely using are lemon (E 330) and milk (E 270) acids, which create an acidic aquatic environment. And use of ammonium carbonate (E 503) and soda (sodium bicarbonate) as a substitute baking powder instead of yeast cause an alkaline environment.

The main components of sweet foods: fats, protein, sugar and flour have a influence on the indices of chemical oxygen consumed (COD - amount of oxygen required for oxidation of organic compounds contained in water), and indicators of biologically oxygen consumed (BOD - amount of oxygen required by microorganisms to sustain life daily). Organic fats influence the regulatory indices of fat in the drains. The proteins contained in sweet foods, gradually decompose, leading to the formation of hydrogen sulfide, ammonia, nitrates and nitrites. The sulfur dioxide - a toxic preservative E 220 is also used in the manufacture of confectionery products based on fruit and berry puree. Therefore the resulting sewage contains salts of sulfuric acid (sulfates). Sewage waters are also characterized by a high content of petroleum products - oils, gasoline and kerosene. In addition, the company has no means of separation of their industrial wastewater and sewage from the administrative buildings. These waters are mixed and flow directly into the cities sewer networks, and this makes cleaning of them particularly difficult.

Other strong pollutants in the cities water system result of the high use of detergents. They often contain salts of phosphoric acid that lead to the formation of phosphate ions, the presence of hydrochloric acid also causes accelerated oxidation of the metal structures within the system. Therefore ions of iron and other metals accumulate in the effluent. Direct and unregulated flow of used cleaning materials into the sewage has exceeded the permissible level of synthetic surface-active substances (SAS). The use of salt in processing of filter regeneration in boiler-rooms also result in formation of chlorides.

Thus, by studying the sewage composition of this confectionery factory, it was shown high acidity and alkalinity levels and excess of phosphates, chlorides, sulfates, iron, hydrogen sulfide, fats, SAS, COD and BOD in comparison with the standard indicators. Other, no less important themes were the topics of solid wastes. It is known that about 400 kg of hazardous wastes are produced for every inhabitant of Donetsk Basin in a year. And the slagheaps have an obvious negative influence on the ecological situation too.

The city of Donetsk and its suburbs have more than 100 slagheaps, of which 35% are inclined to spontaneous combustion. Many of them continue to smoke today, throwing into the air, toxic oxides of carbon, sulfur and nitrogen. Also, these man-made mountains pollute soils, which in turn adversely affect surface water and groundwater quality. Not to mention the areas of useful land that they occupy.

Meanwhile, many components of these slagheaps and mine dumps, especially shales, could be economically, ecologically and efficiently recovered to use as raw materials for metallurgical processes and for the construction industry, for example alumina from which aluminum is smelted. In this regard, students are required to determine the composition of mine waste and make conclusions about the possibility of using them as raw materials.

Knowledge of qualitative and quantitative composition of this slag will optimize the technology of extracting aluminum oxide or other valuable components from these wastes sites. As the burned rocks (slag) consist of oxides of various elements that are very similar in their properties, the problem is their division. Therefore, chemical methods analysis of these rocks instead of instrumental methods can assist to work out a technology for obtaining alumina. They will determine conditions of separation, for example, precipitation of silicate acid and separation of oxides of aluminum, iron, calcium and other components. Solving these problems, students used the classical methods: titrimetric and gravimetric methods, based on the knowledge and skills obtained in the study of analytical chemistry. It was shown that the content of Al₂O₃ in the mine dumps is 17-23%, Fe₂O₃ - 13,8%; SiO₂ - 41.7%. This allows us to make a recommendation for a viable aluminum extraction.

Complex ecological situations around the world compel mankind to seek alternative and safe kinds of fuels derived from renewable sources. World shortages of raw materials have made it necessary to consider and develop new technologies to extract oils from seeds of industrial crops and wild plants, animal fats, agricultural wastes and from food, woodworking and other industries.

During large scale processing of wood in various ways, secondary wood materials - sawdust, wood chips, twigs and other wastes are formed that can be subjected to heat treatment. In the pyrolysis of woody biomass, the reactions of dehydration and condensation of escaped gas| lead to the formation of liquids and solid products, also to depolymerization, with the formation of volatile and resinous liquids. The content of the products obtained can exceed 40% of liquid fuels, 25% - natural gas, 25% - aqueous phase and 10% - charcoal. To increase the yield of liquid fuels is necessary to ascertain the correct catalyst. Therefore, one of the developing biodiesel trends of today is a process of catalytic pyrolysis of wood biomass at relatively low temperatures (300-400⁰C) as heating at higher temperatures increases the yield of resin. As effective catalysts of pyrolysis are considered, - acid solutions (monochloroacetic, sulfuric acid), metal salts, powdered metals (iron, nickel, palladium, etc.). The synthetic polymeric materials are used in pyrolysis too. Synthetic polymers decomposed when heated by a radical mechanism, help to increase the degree of conversion of wood, so the use of such wastes mixed with waste wood to produce liquid fuels may be the solution to the problem of their disposal.

The chair of Chemistry DonNUET is currently, actively researching methods to develop processes for obtaining liquid fuels and their components from woody biomass by its pyrolysis in the presence of additives of synthetic polymers in different environments. The raw materials used, such as pine-oak chips, polyethylene (PE) and polystyrene (PS) have been chosen by us specifically: chips are wastes of furniture production, foamed PE and PS are used as packaging material, which are almost immediately discarded at landfills, so the acquisition of raw materials for the study is easily available and does not require any investment. It is shown that the degree of transformation of the mixture of biomass and synthetic polymer material in the process of pyrolysis is determined by the relative content of its components and the temperature of the process. Thus, students of DonNUET are seeking ways to solve environmental problems in time of the study chemistry in classroom and also in extracurricular time, doing research work in scientific societies.