Pilot-Scale Selective Electrodialysis for the Separation of Chloride and Sulphate from High-Salinity Wastewater

Abstract

The separation of chloride and sulphate is important for the treatment of high salt wastewater, and monovalent selective electrodialysis (MSED) has advantages in terms of energy consumption and pre-treatment costs compared to nanofiltration salt separation. Most of the research on monovalent anion-selective membranes (MASM) is still on a laboratory scale due to the preparation process, cost, and other reasons. In this study, a low-cost, easy-to-operate modification scheme was used to prepare MASM, which was applied to assemble a pilot-scale electrodialysis device to treat reverse osmosis concentrated water with a salt content of 4% to 5%. The results indicate that the optimum operating conditions for the device are: 250 L/h influent flow rate for the concentration and dilute compartments, 350 L/h influent flow rate for the electrode compartment and a constant voltage of 20 V. The separation effect of the pilot electrodialysis plant at optimal operating conditions was: the Cl− and SO42− transmission rates of 80% and 2.54% respectively, the separation efficiency (S) of 93.85% and the Energy consumption per unit of NaCl (ENaCl) of 0.344 kWh/kg. The analysis of the variation of the three parameters of selective separation performance during electrodialysis indicates that the separation efficiency (S) is a suitable parameter for measuring the selective separation performance of the device compared to the monovalent selectivity coefficient (PSO42−Cl−).

Evaluation of Forward Osmosis and Low-Pressure Reverse Osmosis with a Tubular Membrane for the Concentration of Municipal Wastewater and the Production of Biogas

“…Oxidation can be accomplished by ozone or by electrochemical methods Adsorbents and ion exchangers can also be used [ 56 ]. Regarding membrane processes for the removal of salts (such as chlorides), electrodialysis and reverse osmosis are possible techniques [ 57 , 58 , 59 ]. However, improvements of these processes, and subsequently more research, are required for future investigations.…”

Effect of Reverse Osmosis Pre-Processing of Acid Whey and Electrodialysis Current Density on Process Performance

“…An increase in applied current density, and thereby increased transport driving force, decreases the lactate separation efficiency. This means that the increased driving force enhances the transport on lactate more than on the other ions, since lactate is squeezing the transmission of the other ions at these current densities (Li et al, 2022). The difference between the lactate separation efficiency during the first and second hour is less pronounced for sodium and potassium compared to calcium and magnesium, and, in some cases, the lactate separation efficiency even increases during the second hour.…”

“…The lactate (LA) separation efficiency (S) was calculated by Eq. ( 2) previously described by Li et al (2022).…”

Designing an advanced electrodialysis water treatment system to produce drinking water

“…The device had a stack of 40x20 cm and an effective area of 518.5 cm 2 . It had 40 pairs of anion exchange membranes and 41 cation exchange membranes, where the volume of the concentrate, dilute, and electrolyte tank was 10 L [8].…”