The Synergistic Character of Highly N‐Doped Coconut–Shell Activated Carbon for Efficient CO₂ Capture

Abstract

The coconut shell-based activated carbon (AC) surface was effectively anchored with amine moieties with acid treatment followed by tetraethylenepentamine (TEPA) anchoring. The activated carbon surface enhanced with basicity is likely to increase the sorbent properties towards CO 2 adsorption. The AC surface was modified by varying TEPA concentrations. After amine doping, significant loss in textural property indicates their occupation inside the pores and surfaces. Further, the samples were thermally activated to retrieve the textural properties. The physicochemical properties of modified carbon were characterized using BET, TPD, FT-IR, Raman spectroscopy and elemental composition. The amine-modified and thermally activated carbons were tested for CO 2 adsorption up to 25 bar at 25°C. The acid-base properties of N-doped carbons were evaluated using isopropanol as a model test reaction at atmospheric pressure. The IPA reaction products of acetone and propene were quantified for their acid-base nature and correlated to CO 2 adsorption capacities. The CO 2 adsorption capacity increases by tailoring synergistic properties between surface basicity and micropores. Hence, 20 % TEPA-derived nitrogen-enriched carbon reveals a higher yield of acetone 73 %, which in turn enhanced CO 2 adsorption capacity of 9.9 mmol/g, and it is found to be a suitable applicant for CO 2 capture.

Emerging Modification Technologies of Lignin‐based Activated Carbon toward Advanced Applications

“…[102] Recently, activated carbon has been considered as promising matrix for CO 2 capture due to its large specific surface area, porous structure, high adsorption capacity under ambient conditions, and good chemical resistance (Figure 4). [103] LAC will benefit CO 2 capture if it carries high surface area, more micropores and mesopores, and functional groups. LAC prepared from de-alkali lignin was introduced with nitrogen functional groups using NH 3 treatment, and it achieved a CO 2 adsorption capacity of 5.48 mmol g À 1 at 25 °C.…”

“…Recently, activated carbon has been considered as promising matrix for CO 2 capture due to its large specific surface area, porous structure, high adsorption capacity under ambient conditions, and good chemical resistance (Figure 4). [103] …”