Open AccessCapacitive deionization utilizing Activated Biochar – Manganese Dioxide (AB - MD) nanocomposites for desalination applications
Author(s) -
Joemer Adorna,
Myra G. Borines,
Rueyan Doong
Publication year - 2020
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/778/1/012161
Subject(s) - capacitive deionization , materials science , cyclic voltammetry , nanocomposite , chemical engineering , desalination , dielectric spectroscopy , capacitance , activated carbon , faraday efficiency , electrochemistry , biochar , manganese , electrode , adsorption , nanotechnology , chemistry , membrane , metallurgy , organic chemistry , biochemistry , pyrolysis , engineering
Faradaic electric double layer capacitor (EDLC) nanocomposites for desalination were synthesized using coconut-shell derived activated biochar (AB) and manganese dioxide (MnO 2 ) 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-MnO 2 incorporated on the mesoporous activated biochar surface (485.92 m 2 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.