International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The treatment of technological wastewater through a neutralization process is essential for adjusting the chemical properties of the water. This method aims to ensure that the wastewater meets established discharge limits, thereby protecting aquatic ecosystems and improving water quality in local waterways. Effectively managing process wastewater from large industrial facilities, such as copper rolling mills, presents a significant challenge that requires attention. In this paper, we present experimental testing of the neutralization process for technological wastewater from copper rolling mills, conducted at laboratory levels. Experimental research has shown that the neutralization process involves adding 10% Ca(OH)2 until a pH of 8.5 is achieved. The duration of the neutralization process is 30 minutes. During this time, a flocculant called Settafloc AP-17 is added at a concentration of 0.033%, specifically 6 ml per liter. This method effectively meets the water quality standards outlined in the Regulation on Limit Values of Pollutant Emissions into Water and the deadlines for compliance.

Researches in this paper included characterization of bismuth telluride single crystal doped with selenium. In order to study the effect of Se doping on the thermoelectric properties of Bi2Te2.7Se0.3 single crystal, an ingot was prepared by Bridgman method. The Bi2Te2.7Se0.3 single crystal in 11 mm × 80 mm size was grown.
The obtained empirical formula does not deviate from the given compound formula. Bulk sample was characterized by Seebeck coefficient (S) as а function of temperature in the range of 40 – 320°C by а homemade impedance meter.

In this paper, the results of the DTA-TGA, SEM-EDS, and FTIR analysis of the corn silk are presented. The DTA-TGA analysis shows that the decomposition of corn silk has several stages which are manifested with corresponding peaks on obtained DTA-TGA curves. SEM-EDS analysis was performed before and after the adsorption of copper ions. It has shown that untreated corn silk has a non-uniform structure, consisting of channels and cavities of irregular orientation, which facilitates the penetration of the water phase into the adsorbent structure, and incorporation of copper ions in the internal active sites. After the adsorption of Cu2+ ions, the structure becomes more compact, and uniform, as a result of the incorporation of copper ions into the molecular structure of the corn silk. FTIR analysis shows that ion exchange is not the dominant mechanism of binding copper ions to the active sites in the molecular structure of the corn silk, but also chemisorption and physical adsorption is present.