Activated carbons from molasses as CO2 sorbents

Abstract

Aim of this research is to obtain effective, molasses based activated carbon, which would adsorb big amounts of CO2. Molasses was mixed with KOH. Weight ratio of dry materials was 1:1 (AC1, AC3) and 1:2 (only AC2). Homogeneous mixture was obtained. Material was left for 3 h at 25 °C. Drying lasted for 12 h at 200 °C, and the material was grounded. The mixture was pyrolysed at 750 °C, under constant flow (18 dm3/min) of nitrogen. The material was grounded again. Then, powder was washed with water, until filtrate was neutral, which took about 5 dm3 of water. AC3 was washed with 1 dm3 of water. After drying, materials were soaked in HCl (0.1 mol/dm3) for 19 h, and washed with water, until filtrate was neutral. CO2 adsorption was performed under high pressure up to 40 atm, at 40 °C. Specific surface area (according to the Brunauer-Emmett-Teller equation) was calculated for AC1, AC2 and AC3 and it is respectively 1985, 1967, and 2026 m2/g, micropore volume-0.714, 0.707, and 0.728 cm3/g and it was between 75% and 89% of total pore volume. The excess uptake at 40 atm pressure was as follows: AC1-14.02 mmol/g, AC2-12.75 mmol/g, and AC3-15.79 mmol/g.