Comparison of the removal of monovalent and divalent cations in the microbial desalination cell

• Published in: Frontiers of environmental science & engineering 2015-04, Vol.9 (2), p.317-323
• Main Authors: Chen, Shanshan, Luo, Haiping, Hou, Yanping, Liu, Guangli, Zhang, Renduo, Qin, Bangyu
• Format: Article
• Language: English
• Subjects: Calcium chloride; Calcium ions; Cations; Chambers; Charge efficiency; Charge transfer; Desalination; Dialysis; Divalent cations; divalent ion; Earth and Environmental Science; Electric power; electrodes; Electrodialysis; Environment; ion characteristic; Ion concentration; magnesium; Magnesium chloride; microbial desalination cell; Microorganisms; monovalent ion; potassium; Potassium chloride; Research Article; Saline solutions; Sodium; Sodium chloride; 二价阳离子; 微生物; 混合溶液; 电池; 电荷转移效率; 离子半径; 离子浓度; 脱盐率
• ISSN: 2095-2201; 2095-221X
• DOI: 10.1007/s11783-013-0596-y

Microbial desalination cell （MDC） is a promis- ing technology to desalinate water and generate electrical power simultaneously. The objectives of this study were to investigate the desalination performance of monovalent and divalent cations in the MDC, and discuss the effect of ion characteristics, ion concentrations, and electrical characteristics. Mixed salt solutions of NaC1, MgC12, KC1, and CaC12 with the same concentration were used in the desalination chamber to study removal of cations. Results showed that in the mixed salt solutions, the electrodialysis desalination rates of cations were： Ca2＋ 〉 Mg2＋ 〉 Na＋ 〉 K＋. Higher ionic charges and smaller hydrated ionic radii resulted in higher desalination rates of the cations, in which the ionic charge was more important than the hydrated ionic radius. Mixed solutions of NaC1 and MgC12 with different concentrations were used in the desalination chamber to study the effect of ion concentra- tions. Results showed that when ion concentrations ofNa＋ were one-fifth to five times of Mg2~, ion concentration influenced the dialysis more profoundly than electrodia- lysis. With the current densities below a certain value, charge transfer efficiencies became very low and the dialysis was the main process responsible for the desalination. And the phosphate transfer from the anode chamber and potassium transfer from the cathode chamber could balance 1%-3% of the charge transfer in the MDC.