Effects of Nanometer Particle Size on the Properties of Activated Carbon from Terminalia Catappa Fruits Waste

Abstract

Abstract Activated carbon (AC) derived from agricultural by-products, such as Terminalia catappa (TC) fruit waste has been demonstrated as a potential AC material in reducing the production cost in the industry. It also retains the benefits of agricultural by-products, such as being abundant and renewable, environmentally safe, and structurally porous. Several studies have been conducted on the materials’ properties of the prepared ACs from TC fruits at various particle sizes. The top-down approach of high energy ball milling (HEBM) is a simple technique used in reducing the particle size of TC to the nanoscale. Moreover, the ACs have been successfully synthesized by pre-carbonization methods, as well as chemical and physical activations. The pre-carbonization process was performed at 400 oC for 4 hours. The chemical activation was conducted using the KOH impregnation ratio as an activating agent, and a further physical process to activate the carbon was performed in a horizontal tube furnace at 750 oC for two hours with N2 gas flow. The properties and characteristics of Terminalia catappa fruits as ACs were obtained by calculating the percentage yield of ACs and analysis of the surface morphology and elemental composition, particle size, phase analysis, structural analysis, and surface area by using FESEM-EDX, TEM, XRD, Raman spectroscopy, and BET respectively. The percentage yield of ACs was increased with reduced particle size from TC powder, which was in the range of 30–71%. The surface morphology of the prepared ACs reflected the porous structure and the most abundant elements found in the ACs were C, O, and K. The average particle size of all crushed samples obtained was less than 100 nm. The XRD result confirmed the formation of crystalline structures of the graphitic carbon. The results of surface area analysis indicate that the pore size of the activated carbon is mostly in the range of mesopore, whereas the structural analysis depicts that the ratio of ID/IG of AC is nearly the same in between 0.8 to 0.92 and is slightly lower than TC. Thus, the development of agricultural waste-derived mesoporous activated carbon materials is potentially useful for various applications.