EFFICIENCY OF ELECTRODIALYSIS PURIFICATION OF ELECTROPLATING INDUSTRY SOLUTIONS CONTAINING MAGNESIUM SULFATE AND IRON (III) CHLORIDE

Electrodialysis is one of the most popular methods of electrochemical purification using membranes, and the scope of its application is constantly expanding. The aim of the work was to study the kinetic characteristics of multicomponent solution electrodialysis purification of electroplating plants from Mn2+, Fe (common), SO42- and Cl- ions. To achieve this aim, a number of applied tasks were solved. There are measures carrying out for the preparation and conditioning of membranes, experimental studies on electrodialysis purification of several series of model solutions. These solutions were containing MnSO4∙5H2O and FeCl3 in various concentrations up to 0.4 kg/m3 and were similar to wastewater from a separate segment of electroplating industries. Also, analysis of the results obtained on changes in kinetic characteristics in the purification process depends on the time and initial concentration of the solutions was carried out. The separation process was carried out on a laboratory electrodialysis plant using a package of alternating ion exchange membranes MK-40L and MA-41P manufactured by IP Shchekinoazot LLC, Russia. The plant consisted of an electrodialysis cell and three independent circulation lines, each of which is designed for desalinated, concentrated and near-electrode solutions. The solutions were purified with a current density of 20 A/m2. As a result of the work, it was found that a change in the initial concentration of substances in the multicomponent solutions under consideration has a different effect on the electrodialysis purification process, depending on the removal of a specific type of ions. For example, at initially low ion concentrations, high purification rates are observed, that reaching values of 99.5%. However, as the concentration increases, for most of the studied solutions of the "M", "ZH" and "ZHM" series, a significant decrease in purification efficiency occurs when a certain threshold value of the initial concentration is reached. It is important to note that this threshold value can vary significantly depending on the type and it.