Synthesis and characterization of three-dimensional interconnected large-pore mesoporous cellular lignin carbon materials and their potential for CO2 capture

Abstract

Ordered mesoporous lignin carbons with large mesopore sizes and mesopore volumes were synthesized using lignin as a renewable and sustainable polymeric precursor and siliceous mesostructured cellular foam as a template in a solvothermal process. The prepared lignin carbon materials, which are present in arrays of microspheres, showed a quasi-spherical porous morphology and were highly characterized by the rarely seen dominance of a three-dimensional large mesopore system that had a narrow pore size distribution centered at 20–25 nm with high surface areas of up to 960 m2 g−1 and mesopore volumes of up to 1.50 cm3 g−1, respectively. The results also showed that the large-pore mesoporous framework could be readily tuned by varying the carbonization/activation temperature and the silica-to-lignin ratio by mass. Applying the as-prepared carbon materials as porous support for preparing CO2 adsorbent materials demonstrated that the large-pore mesostructured carbon can effectively accommodate a large uploading capacity of polyamines, giving rise to a high CO2 uptake capacity of 129.9 mg-CO2/g-adsorbent or 2.95 mmol-CO2/g-adsorbent with favorable adsorption kinetics at 75 °C and a CO2 partial pressure of 0.15 bar, which is among the best sorbents ever reported under similar adsorption conditions.