Facile Preparation of Biomass-Derived Mesoporous Carbons for Highly Efficient and Selective SO₂ Capture

Abstract

The efficient elimination of SO2 from flue gases and natural gases is critical for energy utilization and environmental protection. However, selecting or preparing an efficient adsorbent with a high SO2 capacity, good selectivity, and excellent recyclability is very challenging, and the adsorption mechanism at an atomic level is still controversial. We report a facile one-step method for the synthesis of biomass-derived porous carbons with high specific surface areas (1195–1449 m2 g–1), mesoporous pore size (4–6 nm), and good SO2 adsorption properties. Our carbon adsorbents exhibited an outstanding SO2 adsorption capacity of 10.7 mmol g–1 at 298 K and 1.0 bar, which is more than twice the SO2 capacity of benchmark carbon material cs1000a (approximately 5.0 mmol g–1) and commercial ordered mesoporous carbon CKM-3 (5.1 mmol g–1). The new carbon adsorbents also showed unprecedented SO2/CO2, SO2/CH4, and SO2/N2 separation selectivities of 32, 127, and 2349, respectively, which are comparable with the best performance MOF adsorbents. Dynamic breakthrough experiments confirmed the feasibility of efficient removal of SO2 from flue gas in an adsorbent column. Even with the presence of water vapor, clear and efficient separation of SO2 could also be achieved with excellent recycling stability. In addition, a density function theory simulation further illustrates that −NO x and −OH groups in the carbon frameworks provide strong interactions with SO2 molecules. The carbon adsorbents synthesized in this work are promising for flue gas desulfurization and natural gas purification applications.

Deep Desulfurization with Record SO2 Adsorption on the Metal–Organic Frameworks

“…Over the past decades, energy-efficient adsorption separation that has showed great potential in desulfurization encourages the development of task-specific adsorbents. − Traditional adsorbents like porous carbons − and zeolites − have been extensively investigated in SO 2 capture and removal. Nevertheless, porous carbons feature the wide pore size distribution and lack strong binding sites, thus showing low selectivity of SO 2 .…”

Chemical immobilization of amino acids into robust metal–organic framework for efficient SO2 removal

“…The increasing energy demands resulting from the booming economy and population growth have resulted in the massive consumption of fossil fuels, 1–3 leading to the emission of a large amount of acid gas emissions including sulfur dioxide (SO 2 ), and have consequently aggravated the air pollution 4 . Typical flue gases discharged from coal‐based fire plants contain a SO 2 concentration between 500 and 3000 ppm, the trace SO 2 can significantly reduce the performances of amine‐based CO 2 scrubbers and irreversibly poisons the noble catalysts in the subsequent NO X reduction and CH 4 combustion 5,6 .…”

Advanced Material‐Oriented Biomass Precise Reconstruction: A Review on Porous Carbon with Inherited Natural Structure and Created Artificial Structure by Post‐Treatment

“…Similar off‐curve property was found in AC samples with impregnation ratio of larger than 3. [ 31–33 ]…”

“…a) Total pore volume versus BET surface area, b) marginal distribution plot of microporosity versus BET surface area, c) BET surface area contour map of impregnation ratio versus activation temperature, and d) microporosity contour map of impregnation ratio versus activation temperature based on biomass‐derived AC with ZnCl 2 activation. [ 30–74 ] …”

“…Similar off-curve property was found in AC samples with impregnation ratio of larger than 3. [31][32][33] Earlier studies revealed that ZnCl 2 activation is favorable for the development of mesoporous structure with medium BET surface area. [3,9] While the collected data in Figure 5b shows a wide and even distribution of micropores ranging from 6.5% to 97.5%.…”