A comparative study on electrosorptive rates of metal ions in capacitive deionization

作者：Li, Yanting; Stewart, Ty C.; Tang, Hao L.^*

来源：Journal of Water Process Engineering, 2018, 26: 257-263.

DOI：10.1016/j.jwpe.2018.10.021

• Electrosorption
• Heavy metal
• Ionic hydrated radius
• Kinetics
• Capacitive deionization

A comparative study on electrosorptive rates was conducted to explore the affinity preference of Na+, K+, Mg2+, Ca2+, Cd2+, Pb2+ and Cu2+ to activated carbon cloth electrodes of capacitive deionization (CDI) in mono-component solutions. Results showed the electrosorptive kinetics of these metal ions followed the Lagergren equation. For alkali and alkali-earth metal ions, the order of electrosorptive rates followed K+ > Na+ > Ca2+ > Mg2+, which revealed an inversely proportional relationship with their ionic hydrated radii. The relationship between electrosorptive rates and ionic hydrated radii, however, did not hold for heavy metal ions, and the order was Cu2+ > Pb2+ > Cd2+. The abnormal electrosorptive behaviors of Cu2+ and Pb2+ could be attributed to electrodeposition and formation of OH- complexes during electrosorption. Besides, Cu2+ and Pb2+ showed significantly low desorption efficiencies during the electrode regeneration processes, indicating serious electrode fouling during the electrosorptive process. This work provides fundamental aspects on individual removal of metal ions and the results can be beneficially used as a reference for treatment and recovery of metal ions by CDI technology.

• 出版日期2018-12
• 单位哈尔滨工业大学