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Separation and recovery of heavy metal ions and salty ions from wastewater by 3D graphene-based asymmetric electrodes via capacitive deionization

Abstract

A novel concept for the separation and recovery of heavy metal ions and salty ions from wastewater by 3D graphene-based asymmetric electrodes via capacitive deionization is presented for the first time. Instead of the traditional practice to adsorb heavy metal by stirring method, we rationally designed functional 3D graphene by grafting ethylenediamine triacetic acid (EDTA) and 3-aminopropyltriethoxysilane on the 3D graphene surfaces, respectively, and take advantage of capacitive deionization for wastewater treatment. In this process, the Pb2+ was adsorbed by EDTA through chelation reaction and the Na+ was adsorbed into the 3D graphene pores by electrosorption. Meanwhile the aminated 3D graphene with 3-aminopropyltriethoxysilane was used as an anode to minimize the co-ion effects and improve the removal efficiency. This research investigated the adsorption and desorption behaviors of Pb2+ and Na+, and investigates the influences of operation conditions, such as pH, voltage, concentration and time on the Pb2+ and Na+ removal. The removal efficiency was 99.9% at pH 6.0 for Pb2+ and 98.7% for Na+. It is worth noting that the Pb2+ and Na+ can be separated and recovered in the desorption process by two steps depending on the different adsorption mechanism between Pb2+ and Na+. The desorption rates were ~99.6% for Pb2+ and ~97.2% for Na+, respectively, and remained at ~94.3% and ~88.2% without further degradation after the 8 cycles. Overall, the CDI with 3D graphene-based asymmetric electrodes is a promising route for the separation and recovery of heavy metals and salty ions from wastewater.

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Publication details

The article was received on 24 Apr 2017, accepted on 15 Jun 2017 and first published on 15 Jun 2017


Article type: Paper
DOI: 10.1039/C7TA03515B
Citation: J. Mater. Chem. A, 2017, Accepted Manuscript
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    Separation and recovery of heavy metal ions and salty ions from wastewater by 3D graphene-based asymmetric electrodes via capacitive deionization

    P. Liu, T. Yan, J. Zhang, L. Shi and D. Zhang, J. Mater. Chem. A, 2017, Accepted Manuscript , DOI: 10.1039/C7TA03515B

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