Capacitive deionization utilizing Activated Biochar - Manganese Dioxide (AB - MD) nanocomposites for desalination applications

Faradaic electric double layer capacitor (EDLC) nanocomposites for desalination were synthesized using coconut-shell derived activated biochar (AB) and manganese dioxide (MnO2) for capacitive deionization (CDI). Three different co-precipitation methods were explored to produce the composite such as:...

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Bibliographic Details
Published in:IOP conference series. Materials Science and Engineering 2020-04, Vol.778 (1), p.12161
Main Authors: Adorna Jr, J, Borines, M G, Doong, R-A
Format: Article
Language:English
Subjects:
activated biochar
Capacitive deionization
Deionization
Desalination
Electric double layer
Electrochemical impedance spectroscopy
Liquid phases
Manganese dioxide
nanocomposite
Nanocomposites
Oxidation
Production methods
Redox reactions
Surface properties
Synergistic effect
Synthesis
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Summary:Faradaic electric double layer capacitor (EDLC) nanocomposites for desalination were synthesized using coconut-shell derived activated biochar (AB) and manganese dioxide (MnO2) for capacitive deionization (CDI). Three different co-precipitation methods were explored to produce the composite such as: (1) indirect liquid-phase combination (ILC) method; (2) direct liquid-phase combination (DLC) method; and (3) acid-assisted grafting oxidation combination (AGO) method. Surface characterization confirmed the presence of α-MnO2 incorporated on the mesoporous activated biochar surface (485.92 m2 g−1) for all the nanocomposites developed. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests show that the three methods yielded a quasi-rectangular and symmetric CV plot indicating good EDLC behavior and a steep EIS plot. The highest specific capacitance of 522.7 F g−1 at 5 mV s−1 was observed using AGO method. CDI tests under 1.2 V at varying NaCl concentrations show high capacitive performance of the synthesized electrodes. The ILC method nanocomposite exhibited superior electrosorptive performance with an electrosorption capacity of 114.11 mg g−1 at 500 ppm NaCl concentration. Due to the synergistic effects of the pseudocapacitive redox reaction of MnO2 and the outstanding double-layer charging of AB on the composite, it serves as a suitable CDI electrode for desalination.
ISSN:1757-8981
1757-899X
DOI:10.1088/1757-899X/778/1/012161