CC BY
6кологическом пространстве Сибири. Научно-популярное издание. - Москва-Барнаул: ИВЭП СО РАН, 2013. 102 с.
9. Ружинская Л.А.Качество жизни населения Рязанского региона: демография, экология, социальные риски -Рязань: Издательство «Концепция» 2013. - 200 с.
10. Города с высокими уровнями загрязнения атмосферного воздуха в 2015 году Окружающая среда в 2015 г. Оперативная информация. Федеральная служба государственной статистики России. - [Электронный ресурс]. -Режим доступа: www.gks.ru
11. Регионы России.Социально-экономические показатели, 2015. Стат.сб. / Росстат. - М., 2015. - 1266 с.
1. Dagbaeva S. Quality of Life: Technology Analysis and Management. - Ulan-Ude, 2011. - 280p.
2. J. Forrester World Dynamics - M, 1978
3. Reimers N. Nature. Reference Dictionary. - M, 1990
4. Geographical research in Siberia. T. 5. Social Geography / P. Baklanov, L. Korytny. - 2007. - 374 p.
5. Ilyasov B., Zakieva E. Model environmental management // Herald of the Ufa State Aviation Technical University. - 2014. - T.18. №3 (64) P.196-202.
6. Ayvazyan S. Comparative analysis of integral quality of life characteristics of the population of the Russian Federation // M, 2001. 64 p.
7. Grishina I., Polynev A., Timonin S. The quality of life of the population of Russian regions: the research methodology and the results of a comprehensive evaluation // Modern productive forces. - 2012. - №1. - p.70-84
8. Rybkin I. The concept of quality of life in space geoecological Siberia. Popular scientific edition. - Moscow-Barnaul IWEP SB RAS, 2013. 102 p.
9. Ruzhinsky L., Quality life of the population of the Ryazan region: demography, environment, social risks - Ryazan, 2013. - 200 p.
10. Cities with high levels of air pollution in 2015 the Environment in 2015 Operational update. Russian Federal Service of State Statistics. - [Electronic resource]. - Access: www.gks.ru11. Regions Rossii.Sotsialno-economic indicators, 2015. Stat.sb. / Rosstat. - M., 2015. - 1266 p.
FERRITISATION AS A METHOD OF ELECTROPLATING SLUDGE DEACTIVATION
Dolbnya I.V.
post-graduate student, specialty is «Ecology» Engels Technological Institute (Branch) of Yuri Gagarin State Technical University of Saratov
Tatarintseva E.A. scientific supervisor, Candidate of Technical Sciences and Assistant professor of the Department of Ecology and Design Engels Technological Institute (Branch) of Yuri Gagarin State Technical University of Saratov
Kozmich C.V. third year student Engels Technological Institute (Branch) of Yuri Gagarin State Technical University of Saratov
Ol'shanskaya L.N.
Doctor of Chemical Sciences, Professor of the Department of Ecology and Design Engels Technological Institute (Branch) of Yuri Gagarin State Technical University of Saratov
ABSTRACT
Large amounts of electroplating sludge are produced every year. It is due to the purification of wastewater of electroplating industry. This pasty sediment is very dangerous for the environment, because it contains different heavy metals that are hazardous for all living organisms. There are lots of methods of electroplating sludge deactivation. One of them is ferritisation, this is a process of sludge stabilization with the formation of ferrites of heavy metals. The main parameters of this process have been determined and studied in the given researches. The obtained substances belong to Class 4 of hazardous goods and they can be stored in a landfill of domestic waste unlike usual sludge. Ferritisation depends on the temperature, the amount of reagents, pH, the character of interfusion and time.
Key words: electroplating sludge, ferritisation, deactivation of hazardous waste, heavy metals.
Introduction people do not think about water in common and take it for
Hydrosphere suffers greatly from the activity of many granted. In fact, water is not a simple substance. Humans do industrial enterprises. It is caused by the flow of toxic not know everything about it. Only two atoms of hydrogen and wastewater into water bodies. Such polluted water can contain one atom of oxygen produce such important matter for the life different substances which are often hazardous. Sometimes of all living organisms, which we know as water [1]. Water is
-109-
of great importance, because it is a basis of life. But nowadays, people have a lot of problems with water, such as lack of water, its pollution and excessive consumption. In this way people have to save available water resources.
Electroplating industry makes a big contribution to the pollution of water bodies. This occurs because of the formation of large amounts of wastewater after technological processes of applying metallic coatings to the surface of details and other components by electrodeposition [2]. Moreover, this field of production has heightened water consumption. The activity of this industry results in the fact that the water that passes through all technological processes contains different heavy metals in high concentrations. These can be nickel, iron, copper, zinc, chromium, manganese and many others. It depends on the composition of a precipitation bath [3]. Such water can be purified up to the necessary concentrations of pollutants. But, as a result, electroplating sludge is formed. This is the second important problem of the protection of the environment which must be resolved.
There are lots of methods of the deactivation of electroplating sludge. It may be leaching valuable metals from the sludge with the help of microorganisms which are harmless for the environment and capable of adsorbing these components [4].
The use of electroplating sludge for the production of building materials can be applied for this purpose [5]. But this way of solving the problem has a lot of difficulties, such as high temperature of the technological process, complicated equipment design, high energy costs, possible formation of new waste products, etc.
Besides, electroplating sludge which contains copper, for example, can be used for conducting aluminothermic neutralization of this metal from it with its further application some technological processes [6]. Moreover, there are lots of other methods which can help to solve this problem with such hazardous materials, for example the use of sludge in the technology of obtaining pigments and powders which contain different metals [6, 7].
At present, the method of ferritisation or ferrite process is of great interest for the investigation. Many authors conduct scientific researches in this field. It is a method of chemical stabilization of electroplating sludge using Fe(SO4) as a precipitating reagent. Such method can neutralize the sludge with different concentrations and kinds of heavy metals [8, 9]. This process consists of two stages Eq. 1, Eq. 2:
(3-n)Fe2+ + nMe2++ 6OH--MenFe3-n(OH)6 (1)
MenFe3-n(OH)6 + O2 - MenFe3-nO4 +2H2O + 2OH- (2)
As a result, new materials such as ferrites of heavy metals can be obtained. These substances have good qualities for their further utilization in water treatment, because of their spinel structure. Moreover, they have excellent magnetic properties, which can be used in other technological processes. And these new materials are almost harmless substances for the environment and are included in Class 4 of Hazardous Goods [10]. And in this case, they can be stored in usual landfills.
In the present study, the method of ferritisation of sludge has been investigated. The possibility of obtaining ferrite compositions from industrial sludge with different
concentrations and kinds of heavy metals has been shown.
Materials and methods
1. Used reagents and chosen materials.
Electroplating sludge of a local industrial enterprise was chosen as the main material for conducting the researches. Electroplating sludge is a pasty sediment of green color (Fig. 1). The color of this material depends on the composition of the sludge, in this case, prevailing metals are nickel and iron. Besides, this sludge contains other heavy metals with various concentrations (Table 1). The goal of the research is choosing optimal conditions to obtain a ferrite substance for the neutralization of industrial sludge and its further use as a material for the creating a composite sorbent for the purification of water environments.
Substance FeSO4 • 7H2O was used as a reagent for conducting sludge stabilization. The solution of this matter was prepared in the mass fraction of the soluble substance equal to 15%.
Sodium hydroxide was used to regulate pH conditions. This is a very important factor in this process. The composition of the solution of this chemical reagent was 22.5% of the mass fraction of the soluble substance.
2. Investigation of the composition of raw electroplating sludge.
The composition of electroplating sludge was investigated by the X-ray fluorescence analysis (Table 1). This method is based on the collection and analysis of a spectrum which was obtained after the excitation of the characteristic X-rays. This emission arises when the atom has a transition from the excitation to the main state. Atoms of different elements emit photons with strictly certain energies. The qualitative elemental composition can be obtained by the measurement of these energies. Emitting intensity is registered with certain energy for the measurement of the quantity of the element (Fig. 2). Fundamental Parameters Method with the device number 4236, Spectron produced in Saint-Petersburg was applied for this goal [11].
3. Conduction of ferritisation of electroplating sludge under the laboratory conditions.
Laboratory equipment consisted of a laboratory glass with the volume of 1L, a hotplate as a source of heat, a thermometer for regulating temperature, tester of pH for the measurement of the quantity of H+ ions, laboratory electrical equipment for the supply of compressed air to the reaction system.
The optimal parameters of ferritisation and the formation of ferrites of heavy metals were determined during the research. The initial concentration of sludge suspension was 50 g/L. Dosage of FeSO4 influences the obtaining of stable compound of ferrites, k = m(Fe2+)/m(sludge) and in the present study it is equal to 0,3 [12]. Parameter k is a criterion of ferritisation. It determines the dosage of iron ions, which is needed for the neutralization of the sludge with the certain mass of the solid phase. And the value of pH plays the most important role for successful results. pH must be equal to 8-12, because the ferrites of heavy metals can be formed in this interval of values [10]. The temperature of this ferrite process conforms to such values as 70-80 oC. The optimal time is 40 min. The continuity of the full chemical reaction was provided during ferritisation. And the turbulent mode of interfusion was applied. Finally, a black sediment was obtained, that was ferrites of heavy metals
having a spinel structure and magnetic qualities (Fig. 3). Then this sediment was separated by filtration. As a result, aqueous solutions were formed and then they were subjected to the analysis to determine the residual concentration of ions of heavy metals by using spectrophotometer Ind.Eco.Lab 5300B. The collected solid was dried under natural conditions, that is at room temperature.
Results and discussions
1. The composition of industrial electroplating sludge.
The primary investigation of the sludge composition shows that this material consists of six types of heavy metals: Ni; Fe; Zn; Cu; Cr; Mn. The initial concentrations are presented in Table 1. The sludge which contained a lot of iron ions was chosen for this investigation, because this research is aimed at the study of magnetic properties of the resulting ferrites and they can allow to use this material as a component of the composite sorbent. But the prevailing metal is nickel.
Fig. i.Industrial electroplating sludge.
Table 1
Data of the element composition of the initial electroplating sludge.
Fig. 2. Qualitative analysis of electroplating sludge.Spectrum Crystal LiF200.
2. Investigation of the filtrate and cleaning water after aqueous solutions. These waters were tested by using special ferritisation. equipment such as Spectrophotometer Ind.Eco.Lab 5300B and
The process of ferritisation resulted in the formation of standard methods such as Natural Normative documents of the
Federation which are established on the territory of the Russian Federation. The results of this research are shown below in Table 2 and Table 3. Nickel has high amounts of the residual concentration in the filtrate. It depends on general percentage of this metal. The amounts of all heavy metals were compared with the values of maximum permissible concentration (MPC) of each heavy metal. These values have been established on the territory of Russia and all industries of production have to follow these recommendations and ranges.
Values of pH and presence of nickel exceed permissible standards of water release at treatment plants of big cities. Thus, the filtrate must be returned to the stage of the repeated treatment. The concentrations of all heavy metals were less
than MPC in cleaning waters. The first investigation of the aquatic system after ferrite process could show the quality and completeness of the chemical process. And the investigation of waters after cleaning the ferrite sediment allows to determine the rate of leachability of each metal.
The magnetic qualities were found by using the external magnet. It is assumed that in further studying the obtained composite sorption material will be easily separated from water after the purification by using an electrical industrial magnet.
The full neutralization of electroplating sludge by conducting the chemical stabilization or ferritisation was needed on the first stage of the investigation.
Fig. 3.Ferrite sludge. Investigation of the filtrate.
Table 2
Metall Residual concentration, mg/L MPC*, mg/L
Ni 0,4 0,1
Fe 0,1 0,3
Zn 0,18 5,0
Cu 0,02 1,0
Cr Less 0,01 0,05
Mn 0,03 0,1
Table 3
Investigation of the cleaning waters.
Metall Residual concentration, mg/L MPC*, mg/L
Ni 0,03 0,1
Fe 0,05 0,3
Zn 0,36 5,0
Cu 0,002 1,0
Cr Less 0,01 0,05
Mn 0,01 0,1
* - the values of MPC for water which is used for the domestic needs.
Conclusions
The method of ferritisation of industrial electroplating sludge has been studied in this research. As a result, the sediment of ferrites with the spinel structure has been made. This compound is of great interest for further study. The results which are presented in this work show the positive data related to this process. The optimal conditions of ferritisation were k = m(Fe2+)/m(sludge) = 0,3; pH = 8-12; t = 70-80 oC; t = 40 min.; the continuity of the process; the turbulent mode of the interfusion. The next step in the scientific work after studying theoretical materials on this theme and obtaining good results in the experiment will be the use of the ferrite sludge
as a constituent of the sorption composite material for the purification of water environments.
Acknowledgement
I express my gratitude to E.A. Tatarintseva, a scientific supervisor, Candidate of Technical Sciences and Assistant professor of the Department of Ecology and Design of Engels Technological Institute for her leadership and support in the conduction of this scientific work. I very thank E.A. Bukharova who heads the Analytical laboratory of Industrial Ecology at Engels Technological Institute (branch) of Yuri Gagarin State Technical University of Saratov for her teaching and support in each issue. I very thank L.V. Kutumova, a senior engineer
of the Analytical laboratory of Industrial Ecology of Engels Technological Institute for her teaching and help in each working situation.
References
1. Spellman F.R. The Science of Water: concepts and applications / F.R. Spellman. - Taylor & Francis Group, LLC, 2008. - pp. 422.
2. Electroplating Effluent Guidelines. United States Environmental Protection Agency (EPA). 2015. Internet resource: www.epa.gov/eg/electroplating-effluent-guidelines
3. Vinogradov S.S. Ecologically Safe Electroplating Production / S.S. Vinogradov. - Publishing house is Globe, Moscow, Russian Federation, 1998. - pp. 302.
4. Wazeck J. Heavy metal extraction from electroplating sludge using Bacillus subtilis and Saccharomyces cerevisiae. Geologica Saxonica / J. Wazeck // Journal of Central European Geology. - 2013. - 59. - pp. 251-258.
5. Klimov E.S. Natural sorbents and chelators in the purification of wastewater / E.S. Klimov, M.V. Buzaeva. -Publishing house is Ulyanovsk State Technical University, Ulyanovsk, Russian Federation, 2011. - pp. 204.
6. Chirikov A.Yu. The Method of Aluminothermic Neutralization and Recycling of Copper Electroplating Sludge / A.Yu. Chirikov, V.P. Reva, A.A. Yudakov, A.V. Perfilev // Russian Journal of General Chemistry. - 2014. - 84 (13). - pp.
2611-2615.
7. Makarov V.M. Complex utilization of sediments of galvanic productions wastewater (electroplating sludge): Dissertation of the Doctor of Technical Sciences. Specialty of Ecology / Makarov V.M.; Ivanovo, Russian Federation, 2001. - pp. 406.
8. Yao-Jen Tu Treatment of complex heavy metal wastewater using a multi-staged ferrite process / Yao-Jen Tu, Chien-Kuei Chang, Chen-Feng You, Shan-Li Wang // Journal of Hazardous Materials. - 2012. - 209-210 (2012). - pp. 379-384.
9. Erdem M. Chromium removal from aqueous solution by the ferrite process / M. Erdem, F. Tumen // Journal of Hazardous Materials. - 2004. - B109 (2004). - pp. 71-77.
10. Semenov V.V. Decreasing the ecological hazard of electroplating sludge by the method of ferritisation: Dissertation of the Candidate of Technical Sciences. Specialty of Ecology / Semenov V.V.; Ulyanovsk, Russian Federation, 2004. - pp. 130.
11. Spectron. XRF Spectrometers &Analizers. 1996-2016. Internet resource: http://spectronxray.ru/en/
12. Buzaeva M.V. Deactivation of industrial wastewater by purification from petroleum products and heavy metals with the use of natural sorbents and chelators: Dissertation of the Doctor of Chemical Sciences. Specialty of Ecology / Buzaeva M.V.; Nizhny Novgorod, Russian Federation, 2011. - pp. 292
-113r
