Understanding the synergy between N-doped ultra-microporous carbonaceous adsorbent and nitrogen functionalities for high performance of CO2 sorption. Issue 1 (February 2021)

• Record Type: Journal Article
• Authors: Ahmed, Rafay; Liu, Guijian; Yousaf, Balal; Rehman, Abdul; Munir, Mehr Ahmed Mujtaba; Irshad, Samina; Rashid, Muhammad Saqib; Cheema, Ayesha Imtiyaz
• Is Part Of: Journal of environmental chemical engineering. Volume 9:Issue 1(2021)
• Publication Date: 2021-02
• Subjects: Chitosan -- CO2 adsorption -- Nitrogen modification -- Chemical activation -- Isosteric heat of adsorption; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2020.104646
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: N-doped ultra-microporous carbons were produced via single-step approach. Synthesized carbons developed highly porous structure and high S BET (1404 m 2 g −1 ). The prepared material showed high CO2 adsorption capacity (5.92 mmol g −1 ). N-functional groups and porous structure played main role in high CO2 uptake. Abstract: Porous carbonaceous adsorbents are believed to encourage contenders to CO2 uptake however their high production cost has urged researchers towards cheap renewable. In this study, nitrogen-doped carbonaceous adsorbents with high ultra-microporous structure were synthesized by carbonization and activation of chitosan along with urea and KOH simultaneously at various temperatures (600−900 °C). The effects of temperature, urea modification, and chemical activation on nitrogen functionalities and development of porous structure were analyzed. Results showed that porous carbons synthesized with urea and KOH modification at 700 °C exhibit the highest CO2 adsorption value (5.92 mmol g −1 at 0 °C and 4.45 mmol g −1 at 25 °C). Enhanced adsorption by NCABC-700 was found due to synergistic effect of nitrogen as well as high specific surface area (1404 m 2 g −1 ) and micropore volume (0.68 cm 3 g −1 ), respectively. Furthermore, best fitting of Freundlich isotherm model explained heterogeneous nature of adsorbent. Isosteric heat of adsorption with a value of 42.2 kJ mol -1, also indicated the presence of N containing functional groups and a high number of micropores that created a strong interaction between adsorbent and adsorbate, helping in high CO2 uptake.