Thermodinamic analyzing of heavy metals precipitation for their recovery from industrial wastewaters

This work seeks to develop a suitable heavy metals precipitation modeling approach that could give reasonable results in mainstreamuse with industrial wastewater treatment. This paper is devoted to the thermodynamic analysis of the degree of precipitation ofslightly soluble hydroxides and salts in industrial wastewaters in order to optimize the technological schemes of extraction and reuseof heavy metals from industrial waste. Based on the notion of the solubility product, the equations describing the dependence ofthe precipitation degree of the metal ion ? in the form of slightly soluble salts and hydroxides on the initial concentrations of thecomponents, including complexing agents, and the pH of the solution, have been deduced. The thermodynamic meaning of thequantity ? has been revealed. Possibility of forming stable complexes between the metal ion and complexing agents in galvanicwastewater is taking into account. Degree of precipitation (in parentheses, %) and distribution of chemical species of metal ions (Al(43), Cr (0), Fe (100), Zn (0), Sr (100) and Ba (100)) from the multicomponent industrial effluents of an engineering company(electroplating units of the Tactical Missiles Corporation, Dubna, Russia) were analyzed at pH 6.