Scaling on Surface of MA-41P Anion-Exchange Membrane in Concentration Chamber of Electrodialyzer during Processing Dilute Stratal Water Imitates

Abstract

The results of the study of the oscillations in the chronopotentiograms during scaling on the surface of an MA-41P anion-exchange membrane facing the concentration chamber of an electrodialyzer during the processing of dilute stratal water similar in composition to natural brines incidentally produced in the gas and oil fields of the Angara–Lena basin are presented. If Mg²⁺ ions are present in the solution, porous Mg(OH)₂ is predominantly formed on the surface of an MA-41P membrane despite the excess Ca²⁺ content and sufficient amount of \({\text{HCO}}_{3}^{ - }\) in the solution. In the absence of Mg²⁺ ions in the solution, CaCO₃ precipitates on the surface of the membrane. During scaling, an increase in the amplitude and period of the oscillation of the potential drop ∆φ from 5 mV and on average 5–10 s (due to the development of equilibrium electroconvection) up to 50 mV and 430 s, respectively, is recorded in the chronopotentiograms of MA-41P membrane. It is established that the amplitude and period of oscillations of the potential drop as well as the pH values of the concentrate can serve as a signal for taking actions to flush and regenerate ion-exchange membranes during the electrodialysis processing of dilute solutions of stratal water.