Preparation and characterization of hydrochar-derived activated carbon from glucose by hydrothermal carbonization

Abstract

Activated carbon (AC) was produced from glucose using hydrothermal carbonization (HTC) and KOH activation. The HTC temperature was 170–280 °C over 30min–12h of holding time and the KOH activation temperature was 500–700 °C at 1 h. The results show that there are several carbon spheres of 0.6 to 7 μm in the hydrochar. The hydrochar contained many aromatic rings and oxygen-containing functional groups. The hydrochar obtained from glucose was used as precursor, whereas KOH was used as activating agent. The pore characteristic of activated carbon changes significantly with the impregnation ratio and activated temperature. The dry-basis AC yield was in the range of 42.23–55.8wt.%. The maximum Brunauer–Emmett–Teller (BET) surface area of the product was 1413.62 m2/g. The average pore size of the AC was 2.2 to 2.5 nm with total pore volume of 0.2–0.47 cm3/g. The maximum surface area and pore volume were reached at a 1:4 impregnation ratio (hydrochar:KOH) and 700 °C temperature. The pore size of glucose-activated carbon is less than 10 nm, and most of the pores are micropores and mesopores. The existence of mesopores and micropores in activated carbon can enhance their adsorption capacity, especially for macromolecular adsorbent.