Use of electrodialysis to deionize acidic wastewater streams

Abstract

The use of electrodialysis to deionize an acidic process water stream is discussed. Direct electrodialysis of the stream containing hydrochloric acid was studied, as well as electrodialysis of a stream containing NaCl, which would result from neutralization of the process stream with caustic. Current efficiency, stack resistance, and osmotic water transfer were measured at various concentrations and stack voltages. If the ions are being transferred into a stream with low electrolyte concentration, direct electrodialysis of acid is the preferred route because of lower stack resistance. However, if the purpose of operation is reuse of process water, the electrolyte must be transferred into a very concentrated stream. In this case, neutralization prior to electrodialysis is preferred because, otherwise, very low current efficiency and high osmotic water transfer are observed.

The Feasibility of Energy Extraction from Acidic Wastewater by Capacitive Mixing with a Molecular‐Sieving Carbon Electrode

“…Most of the acidic wastewater also containsh eavy metals; however, these can be extracted by methods such as supplied or chelating precipitation, ion exchange, electrochemical treatment, adsorption,a nd membrane filtration [3][4][5][6][7] After removalo ft he hazardous heavy metals, the acidic wastewater disposal itself is still of great concern for the environment and ecological systems. The most commonm ethods for acidic wastewater regeneration are electrodialysis, [8] nanofiltration, [9] and diffusion dialysis. The most commonm ethods for acidic wastewater regeneration are electrodialysis, [8] nanofiltration, [9] and diffusion dialysis.…”

“…Although the popular convention is to disposew aste acid solutionst hrough direct discharge after neutralization by alkaliner eagents, several techniques for reusinga cidic wastewater exist. The most commonm ethods for acidic wastewater regeneration are electrodialysis, [8] nanofiltration, [9] and diffusion dialysis. [10] Of these three methods, diffusion dialysis is the least energy intensive and has been gaining popularity over the last years.…”

Electrodialysis Applications for Pollution Prevention in the Chemical Processing Industry

“…ED has been demonstrated for the recovery of sulfuric 2 and hydrochloric acid. 21 Sodium hydroxide has been produced from sodium chlorate as a feed to a chlorine dioxide generator. 8 Salts have been recovered as well.…”

Electrodialytic removal of nitrates and hardness from simulated mixtures using ion‐exchange membranes

“…In addition, this method has been widely used for production of table salt and organic acids, remediation of heavy metal polluted soil, sugar demineralization, blood treatment, and wine stabilization. [2][3][4][5][6] Nitrogen is essential for all living things because it is a component of protein. Nitrogen exists in the environment in many forms and it changes its form when it moves through the nitrogen cycle.…”