Electro-enhanced removal of perchlorate ions from aqueous solution using capacitive deionization process

• Published in: Journal of industrial and engineering chemistry (Seoul, Korea) 2020, 89(0), , pp.351-360
• Main Authors: Divyapriya, Govindaraj, kumar, Keshav V., Rajesh, Lohita, Nambi, Indumathi M.
• Format: Article
• Language: English
• Subjects: Capacitive deionization; Graphite felt; Isotherm; Kinetics; Perchlorate removal; 화학공학
• ISSN: 1226-086X; 1876-794X
• DOI: 10.1016/j.jiec.2020.06.002

[Display omitted] •Electrosorption process has been successfully employed to remove ClO4− ions.•Graphite felt showed good capability for electrosorption of ClO4− by EDL charging.•The maximum adsorption capacity was found to be 21.1mgg−1.•The electrosorption rate at 1.0V was five times the open circuit voltage.•The electrodes are easily regenerated for multiple cycles by reversing the voltage. The study was performed to understand the feasibility of graphite felt for electro-enhanced removal of perchlorate ions through capacitive deionization process (CDI) in aqueous solution. The cyclic voltammetry studies indicated that the perchlorate ions neither get oxidized nor reduced under the operating conditions for the applied potential range of 1.5V. The effect of voltage, flow rate, perchlorate concentration, pH of the solution and temperature on the electrosorption was studied. The electrosorption capacity increased with increasing applied potential, flow rate and perchlorate concentration. The change in pH significantly affected the removal efficiency due to competitive ionic effect. The increase in temperature had a negative impact on the electrosorption capacity. Langmuir model was found to be a better fit than the Freundlich model and the maximum electrosorption capacity was found to be 21.1mgg−1. It was observed that electro-enhanced adsorption followed pseudo first order kinetic model with a rate constant of 0.45min−1 for an initial concentration of 1000mgL−1 operated at 1.5V. Moreover the graphite felt exhibited good repeatability of the electrosorption process and affinity toward perchlorate ions. Thus it can be concluded that the graphite felt electrode can be potentially used for electrosorptive removal of perchlorate ions from the aqueous solution.