Ultra-microporous cotton fiber-derived activated carbon by a facile one-step chemical activation strategy for efficient CO2 adsorption

The CO2 capture by absorbent shows a great promise to remit the pressure of CO2 discharge. The functionalization of N surfaces and the development of the surface area in activation modification have received a great deal of attention as important factors influencing CO2 adsorption performance. However, the role of ultra-micropores in the capture by size matching of CO2 by adjusting the CO2 size and the absorbent pore structure has been less studied to some extent. The study provides a simple one-step chemical activation method, in which cotton fibers were utilized as biomass sources to construct ultra-microporous carbon absorbent with a simple and effective tunable pore structure by changing the alkali-carbon ratio and activation temperature. The series of samples both showed high CO2 adsorption at normal pressure, in particular, the optimal sample CC2-800 affords 4.43 mmol g-1 CO2 uptake at 298 K and 6.58 mmol g-1 CO2 uptake at 273 K. Impressively, the optimal adsorbent was endowed with extremely low adsorption heat, thereby showing good reversibility and reusability during multiple-cycle tests at room temperature. By a comprehensive study of the structural characteristics of the adsorbent, this research further validates the significant role of ultra-micropores in CO2 adsorption. Additionally, the simple one-step preparation process shows crucial significance for sustainable development and environmental friendliness, which provides some interesting insights for the design and development of ultramicroporous activated carbon.

Automated summary

The capture of CO2 by absorbent has the potential to reduce CO2 emissions. The functionalization of N surfaces and the development of the surface area have been recognized as important factors in CO2 adsorption performance. However, the role of ultra-micropores in size matching of CO2 and absorbent pore structure has not been extensively studied. This study presents a simple one-step chemical activation method to create ultra-microporous carbon absorbent with tunable pore structure. The optimal sample showed high CO2 adsorption at normal pressure and low adsorption heat, demonstrating good reversibility and reusability.