D. I. Mendeleyev Russian University of Chemical Technology, Moscow, Russia

A. M. Gaydukova, Associate Professor, Candidate of Technical Sciences, e-mail: gaydukovaam@yandex.ru
T. V. Konkova, Professor, Doctor of Technical Sciences
T. N. Krylova, Postgraduate Student
A. V. Lavkova, Magister

The efficiency of wastewater treatment methods is significantly affected by the origin of the effluents, the initial concentration of pollutants, pH, and the presence of complexing agents. Studies were conducted on the extraction of copper (II) ions from wastewater containing a complexing agent – tartrate ion, during filtration, electroflotation with the addition of a coagulant, as well as a combined method including sorption in a static mode and electroflotation. To implement the filtration and electroflotation methods, it is necessary to convert impurities into slightly soluble compounds, for example, in the process of neutralizing acidic and alkaline wastewater with the formation of metal hydroxides. However, this approach is not feasible in wastewater containing a complexing agent. It was found that slightly soluble compounds are formed when adding the surfactant SeptaPAV to wastewater, with an increase in the concentration of which to 0.6 g/l, the residual concentration of Cu²⁺ decreases from 38 to 7 mg/l during filtration and to 3.8 mg/l du ring electroflotation. However, these methods do not allow extracting organic impurities. To solve this problem, studies were conducted on the effect of a coagulant based on iron and aluminum chlorides on the efficiency of electroflotation and wastewater filtration. It was found that the introduction of 300 mg/l of coagulant does not allow purifying the wastewater not only from the organic component, but also from copper ions. The particle size and their electrokinetic potential were determined, and based on these data, a flocculant was selected that can increase the purification degree to 60% for copper (II) ions as a result of filtration. At the same time, organic impurities remain in the drain. An electroflotation sorption method is proposed that allows for wastewater purification to 96–99% for both copper (II) ions and organic substances.

1. Kolesnikov V. A., Gubin A. F., Kolesnikova O. Yu., Perfileva A. V. Increasing the efficiency of electroflotation purification of printed circuit board production wastewater from copper ions in the presence of complexing agents, surfactants and flocculants. Zhurnal prikladnoy khimii. 2017. Vol. 90, No. 5. pp. 598–603.

2. Aung Pyae, Kolesnikova O. Yu., Hein Tu Aung, Kolesnikov V. A. Electroflotation extraction of a mixture of copper and zinc ions from aqueous solutions in the presence of NH3. Izvestiya vuzov. Khimiya i khimicheskaya tekhnologiya. 2021. Vol. 64, Iss. 10. pp. 119–124. DOI: 10.6060/ivkkt.20216410.6322
3. Kolesnikov V. A., Varaksin S. O., Kryuchkova L. A. Electroflotation extraction of valuable components from galvanic production wash waters with water return to circulation. Elektrokhimiya. 2001. Vol. 37, No. 7. pp. 887–891.
4. Rajoria S., Vashishtha M., Sangal V. K. Treatment of electroplating industry wastewater: a review on the various techniques. Environmental Science and Pollution Research. 2022. Vol. 29. pp. 72196–72246.
5. Kolesnikov A. V., Than So Htay, Kolesnikov V. A., Kovalenko V. S. Extraction by electroflotation of iron, chromium and aluminium hydroxides from aqueous solutions of sodium chlorides and sulphates in the presence of Mg2+, Ca2+ and surfactants of different types. CIS Iron and Steel Review. 2020. Vol. 20. pp. 61–65.
6. Shadi A. M. H., Kamaruddin M. A., Niza N. M., Emmanuel M. I. et al. Electroflotation treatment of stabilized landfill leachate using titanium-based electrode. International journal of Environmental Science and Technology. 2021. Vol. 18. pp. 2425–2440.
7. Djelad A., Morsli A., Robitzer M., Bengueddach A. et al. Sorption of Cu(II) ions on chitosan-zeolite X composites: impact of gelling and drying conditions. Molecules. 2016. Vol. 21, Iss. 1. 109. DOI: 10.3390/molecules21010109
8. Smirnova N. N., Afonin G. S. Influence of the nature of ligands on the sorption of copper (II) ions by activated carbons and ion-exchange resins. Sorbtsionnye i khromatograficheskie protsessy. 2017. Vol. 17, No. 3. pp. 422–428. DOI: 10.17308/sorpchrom.2017.17/396
9. Tumin N. D., Chuah A. L., Zawani Z., Rashid S. A. Adsorption of copper from aqueous solution by elaisguineensis kernel activated carbon. Journal of Engineering Science and Technology. 2008. Vol. 3, No. 2. pp. 180–189.
10. Yue Teng, Jiawei Zhu, Shan Xiao, Zhengzhuo Ma. et al. Exploring chitosan-loaded activated carbon fiber for the enhanced adsorption of Pb(II)-EDTA complex from electroplating wastewater in batch and continuous processes. Separation and Purification Technology. 2022. Vol. 299. 121659. DOI: 10.1016/j.seppur.2022.121659
11. Brusnitsyna L. A., Stepanovskikh E. I. Printed circuit board manufacturing technology: tutorial. Yekaterinburg : Izdatelstvo Uralskogo universiteta, 2015. 200 p.
12. GOST 23770–79. Printed circuit boards. Standard processes of chemical and galvanic metallization. Introduced: 01.07.1981.
13. GOST 31859–2012. Water. Method for determination of chemical oxygen demand. Introduced: 01.01.2014.
14. Gaydukova A. M., Kolesnikov V. A., Napreeva A. D., Kondratieva E. S. Extraction of carbon sorbents from aqueous solutions. Tsvetnye Metally. 2021. No. 10. pp. 31–36.
15. Gaydukova A. M., Kolesnikov V. A., Brodskiy V. A., Kolesnikov A. V. Electroflotation extraction of carbon material powders in the presence of metal ions. CIS Iron and Steel Review. 2021. Vol. 22. pp. 102–106.
16. Kolesnikov V. A., Gubin A. F., Kolesnikova O. Yu., Kondratieva E. S. Electroflotation extraction of poorly soluble copper compounds from printed circuit board production wash waters. Teoreticheskie osnovy khimicheskoy tekhnologii. 2016. Vol. 50, No. 4. pp. 393–401.DOI: 10.7868/s0040357116040060
17. Gaydukova A., Kolesnikov V., Stoyanova A., Kolesnikov A. Separation of highly dispersed carbon material of OU-B grade from aqueous solutions using electroflotation technique. Separation and Purification Technology. 2020. Vol. 245. 116861. DOI: 10.1016/j.seppur.2020.116861
18. Kolesnikov V. A., Ilyin V. I., Brodsky V. A., Kolesnikov A. V. Electroflotation in the processes of water purification and extraction of valuable components from liquid technogenic waste: review. Teoreticheskie osnovy khimicheskoy tekhnologii. 2017. Vol. 51, No. 4. pp. 361–375. DOI: 10.7868/S0040357117040054
19. Khasanov Sh. A. Reagents for water purification. Moscow : U Nikitskikh vorot, 2023. 832 p.