Enhanced electrochemical performances of peanut shell derived activated carbon and its Fe3O4 nanocomposites for capacitive deionization of Cr(VI) ions

G Bharath; K Rambabu; Fawzi Banat; Abdul Hai; Abdul Fahim Arangadi; N Ponpandian

doi:10.1016/j.scitotenv.2019.07.069

Enhanced electrochemical performances of peanut shell derived activated carbon and its Fe₃O₄ nanocomposites for capacitive deionization of Cr(VI) ions

Sci Total Environ. 2019 Nov 15:691:713-726. doi: 10.1016/j.scitotenv.2019.07.069. Epub 2019 Jul 6.

Authors

G Bharath¹, K Rambabu², Fawzi Banat³, Abdul Hai², Abdul Fahim Arangadi², N Ponpandian⁴

Affiliations

¹ Department of Chemical Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates. Electronic address: bharath.govindan@kustar.ac.ae.
² Department of Chemical Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates.
³ Department of Chemical Engineering, Khalifa University of Science and Technology, P.O. Box 127788, Abu Dhabi, United Arab Emirates. Electronic address: fawzi.banat@ku.ac.ae.
⁴ Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India.

PMID: 31325869
DOI: 10.1016/j.scitotenv.2019.07.069

Abstract

Capacitive deionization (CDI) is one of the most efficient and emerging techniques for the removal of toxic metal ions from aqueous solutions. In this study, mesoporous peanut shell derived activated carbon (PSAC) was prepared by low temperature pyrolysis at 500 °C. Subsequently, a novel iron oxide/PSAC (Fe₃O₄/PSAC) nanocomposite adsorbent was prepared via facile one-pot hydrothermal synthesis method at 180 °C. Nucleation growth mechanism and appropriate characterizations of prepared nanocomposites were investigated. The obtained Fe₃O₄/PSAC possessed a highly mesoporous structure, and a large specific surface area (680 m²/g). The electrochemical analysis showed that the obtained Fe₃O₄/PSAC nanocomposites exhibited higher capacitance (610 F/g at 10 mV/s), good stability and low internal resistance. A batch mode adsorption and CDI based Cr(VI) removal studies were conducted. Effects of solution pH and cycle time on Cr(VI) electrosorption capacity were further investigated. The Fe₃O₄/PSAC based electrodes exhibit a maximum electrosorption capacity of 24.5 mg/g at 1.2 V, which was remarkably larger than other reported materials. The fabricated composite displayed higher electrosorption capacity with rapid time and a favorable reduction of Cr (VI) to Cr(III). Studies indicated that the Fe₃O₄/PSAC based CDI electrode possesses a good potential to be applied for the removal of toxic metal ions from wastewater.

Keywords: Capacitive deionization; Electrosorption; Heavy metals removal; Nanocomposites; Supercapacitance.