Characterization of Chemically Activated Carbons Prepared from Miscanthus and Switchgrass Biomass

Abstract

Lignocellulosic biomass, including that of energy crops, can be an alternative source to produce activated carbons (ACs). Miscanthus and switchgrass straw were used to produce ACs in a two-step process. Crushed plant material was carbonized at 600 °C and then obtained carbon was activated using NaOH or KOH at 750 °C. The content of surface oxygen groups was determined using Boehm’s method. The porosity of ACs was assayed using the nitrogen adsorption/desorption technique, while their thermal resistance using the thermogravimetric method. The ACs derived from miscanthus and switchgrass were characterized by surfaces rich in chemical groups and a highly developed porous structure. The highest specific surface areas, over 1600 m2/g, were obtained after carbon treatment with NaOH. High values of iodine number, 1200–1240 mg/g, indicate an extensive system of micropores and their good adsorption properties. The type of activator affected the contents of oxygen functional groups and some porosity parameters as well as thermal stability ranges of the ACs. Among obtained carbons, the highest quality was found for these derived from M. sacchariflorus followed by switchgrass, after activation with NaOH. Hence, while these crop species are not as effective biomass sources as other energy grasses, they can become valuable feedstocks for ACs.

Sheet-like Skeleton Carbon Derived from Shaddock Peels with Hierarchically Porous Structures for Ultra-Fast Removal of Methylene Blue

“…Porous and thin sheet-like structures of SPACs were obtained with the carbonization procedure after NaOH activation. The chemical activation mechanism of NaOH can be depicted in Equations ( 3)-( 6) [21][22][23][24]. Firstly, Na 2 CO 3 and H 2 components are generated by reaction of NaOH and C. Then, part of the Na 2 CO 3 reacts with C to produce CO, and the other part decomposes into Na 2 O and CO 2 components under the employed high temperature conditions.…”

Biosorption of Methylene Blue by Activated Carbon from Sugarcane Waste (ACSW)

“…Lignocellulose has active C-O, NH and OH goups which can be modified to form pore structures and high surface area to increase bioadsorbent capability [6]. The abundance and availability of lignocellulosic waste for the production of activated carbon (KA) at a low cost, so it is widely applied in various studies, namely water purification, heavy metal adsorption, dyes, organic/inorganic compounds, as a catalyst and the basic material for making capacitors and batteries [7][8][9].…”

“…In applications, the adsorption capacity produced is high [10]. Surface activated carbon (KA) is charged (+), so to increase the capability of bioadsorbent can be modified through active goups of CO, NH and OH to form pore structures and high surface area [8], as well as through the [9] in applications can be modified through processing methods and conditions such as heating rate, temperature, time, activating media and degee of activation. Activated carbon (KA) produced is stable in high temperatures, has reactivity, surface area ± 3000 m 2 /g, porosity and high carbon content [11][12].…”

Research on the Development of Technologies for the Production of Granulated Activated Carbons Using Various Binders

“…The most expected is to produce a universal sorbent with very good sorption properties [ 6 ]. The production of the activated carbon is based on various materials of organic origin, such as wood, hard and brown coal, polymers and waste from the wood industry, fruit stones and shells, various raw materials and materials of synthetic origin [ 7 , 8 , 9 , 10 , 11 , 12 ]. Apart from coal raw materials, various types of binders are used to produce activated carbons.…”

“…Apart from coal raw materials, various types of binders are used to produce activated carbons. As binders, coal tar, methyl cellulose, bentonite, clay, sugars, glycerine, glycol, various oils and many other substances are most often used [ 7 , 8 , 9 , 10 , 11 , 12 ]. They may also be waste substances from industrial production [ 13 ].…”