Study of Kinetic and Structural Characteristics of Membranes in Purification Process of Copper-Containing Solutions by Electrodialysis

Abstract

This paper presents the analyzed results of the study of structural and kinetic characteristics of ion-exchange membranes MA-40, MK-40, PC Acid 60 and CM(H) (RALEX®) during separation and concentration of copper-containing solutions in the electrodialysis process. In particular, the sizes of amorphous and crystalline regions of the membrane material structure and the degree of crystallinity were determined, the retention factor of cation Cu2+ and anions NO3- and SO42- were calculated. It was found that for mA-40 and MK-40 membranes the structure of the membrane material changes during water saturation, what in turn can affect the kinetics of mass transfer through the membrane. In addition a low sensitivity of membrane material to mechanical and thermal loads under cyclic operating conditions is detected. This is confirmed by the coincidence of diffraction angles at which peaks of dry and water-saturated samples of membranes are observed, and by a non-significant change in the x-ray degree of crystallinity of the membrane material within 5-7% in the smaller side for water-saturated samples. The data, which were obtained during this work, indicate a relatively good cleaning of copper-containing solutions by electrodialysis from extraneous ions (NO3- and SO42-) at high values of Cu2+ cations concentration. In the initial section, slightly less than 90% of Cu2+ cations are retained, while NO3- and SO42- anions remain significantly less – about 16.7% and 25.7%, respectively. It should be noted that the most optimal parameters of electrodialysis are required for maximizing the efficiency of concentration.

Copper Recovery From Ammonia Solutions Through Electro-Electrodialysis (EED)

“…The copper recovery process as a cathodic deposit by EED is dependent on several factors that theoretically determine its electrodeposition at the cathode: among them are electrode nature, ion exchange membrane, current density, temperature, volumetric flow, working time, and pH of the electrolyte ( Audinos, 1986 ; Shestakov et al, 2019 ).…”

“…From this, it is possible to obtain species of commercial value in the electrolytes and at the electrodes. The EED cells are composed of two electrodes, cathode and anode, separated by an ionic membrane ( Shestakov et al, 2019 ; Jiang et al, 2014 ; Ran et al, 2017 ). The membranes for use in EED can either be 1) cationic membranes that have negative fixed groups with positive mobile ions that allow movement of cations or 2) anionic membranes that have positive fixed groups and against negative mobile ions that allow the passage of anions through it.…”

Influence of Surface Modification of MK-40 Membrane with Polyaniline on Scale Formation under Electrodialysis

“…To ensure the mechanical strength, the membrane is reinforced with a nylon mesh. MK-40 membranes are used in the electrodialysis concentration and demineralization of electrolyte solutions [ 28 , 29 , 30 , 31 ]. The closest analog of this membrane is the Ralex-CMH membrane produced by MEGA a.s. (Straz pod Ralskem, Czech Republic).…”