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Issue 28, 2017
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Separation and recovery of heavy metal ions and salt ions from wastewater by 3D graphene-based asymmetric electrodes via capacitive deionization

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Abstract

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

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

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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, 2017,5, 14748-14757
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    Separation and recovery of heavy metal ions and salt 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, 5, 14748
    DOI: 10.1039/C7TA03515B

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