Highly porous activated carbons from resource-recovered Leucaena leucocephala wood as capacitive deionization electrodes

• Published in: Chemosphere (Oxford) Vol. 141; pp. 71 - 79
• Main Authors: Hou, Chia-Hung, Liu, Nei-Ling, Hsi, Hsing-Cheng
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2015
• Subjects: Activated carbon; Activation; Capacitive deionization (CDI); Carbon electrode; Charcoal - chemistry; Chars; Combustion; Deionization; Electric Capacitance; Electrochemical Techniques - instrumentation; Electrodes; Fabaceae - chemistry; Fabaceae - growth & development; Leucaena; Leucaena leucocephala; Models, Chemical; Porosity; Salinity; Seawater - chemistry; Surface Properties; Taiwan; Wood; Wood - chemistry; Taiwan; Carbon electrode; Activation; Leucaena leucocephala; Capacitive deionization (CDI)
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2015.06.055

•Highly porous activated carbons were prepared from waste L. leucocephala wood.•Overgasification caused the pores of activated carbon mainly in mesopore range.•The carbons had typical capacitive behaviors for electrical double layer formation.•A mixture of mesopores/micropores caused greater electrosorption performance.•Carbons from L. leucocephala are suitable electrodes for capacitive deionization. Highly porous activated carbons were resource-recovered from Leucaena leucocephala (Lam.) de Wit. wood through combined chemical and physical activation (i.e., KOH etching followed by CO2 activation). This invasive species, which has severely damaged the ecological economics of Taiwan, was used as the precursor for producing high-quality carbonaceous electrodes for capacitive deionization (CDI). Carbonization and activation conditions strongly influenced the structure of chars and activated carbons. The total surface area and pore volume of activated carbons increased with increasing KOH/char ratio and activation time. Overgasification induced a substantial amount of mesopores in the activated carbons. In addition, the electrochemical properties and CDI electrosorptive performance of the activated carbons were evaluated; cyclic voltammetry and galvanostatic charge/discharge measurements revealed a typical capacitive behavior and electrical double layer formation, confirming ion electrosorption in the porous structure. The activated-carbon electrode, which possessed high surface area and both mesopores and micropores, exhibited improved capacitor characteristics and high electrosorptive performance. Highly porous activated carbons derived from waste L. leucocephala were demonstrated to be suitable CDI electrode materials.