The Novel Strategy for Increasing the Efficiency and Yield of the Bipolar Membrane Electrodialysis by the Double Conjugate Salts Stress

Polymers

Chunxu Li¹  Wenjuan Qu²  Guohui Wang²  Dong Wang²  Meng Zhang²  Shaoxiang Li²  Yunna Lei²  Jiaji Cheng²  Wenqiao Meng² 

[1] ASTUTE 2020 in Future Manufacturing Research Institute, College of Engineering, Swansea University, Swansea SA1 8EN, UK;College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao 266042, China;

关键词: bmed;    current efficiency;    conjugate salt;    influence factor;   

DOI  :  10.3390/polym12020343

来源: DOAJ

【 摘 要 】

To improve sulfuric acid recovery from sodium sulfate wastewater, a lab-scale bipolar membrane electrodialysis (BMED) process was used for the treatment of simulated sodium sulfate wastewater. In order to increase the concentration of sulfuric acid (H₂SO₄) generated during the process, a certain concentration of ammonium sulfate solution was added into the feed compartment. To study the influencing factors of sulfuric acid yield, we prepared different concentrations of ammonium sulfate solution, different feed solution volumes, and different membrane configurations in this experiment. As it can be seen from the results, when adding 8% (NH₄)₂SO₄ into 15% Na₂SO₄ under the experimental conditions where the current density was 50 mA/cm², the concentration of H₂SO₄ increased from 0.89 to 1.215 mol/L, and the current efficiency and energy consumption could be up to 60.12% and 2.59 kWh/kg, respectively. Furthermore, with the increase of the volume of the feed compartment, the concentration of H₂SO₄ also increased. At the same time, the configuration also affects the final concentration of the sulfuric acid; in the BP-A-C-BP (“BP” means bipolar membrane, “A” means anion exchange membrane, and “C” means cation exchange membrane; “BP-A-C-BP” means that two bipolar membranes, an anion exchange membrane, and a cation exchange membrane are alternately arranged to form a repeating unit of the membrane stack) configuration, a higher H₂SO₄ concentration was generated and less energy was consumed. The results show that the addition of the double conjugate salt is an effective method to increase the concentration of acid produced in the BMED process.

【 授权许可】

Unknown