Lignin-Based Porous Supraparticles for Carbon Capture

Multiscale carbon supraparticles (SPs) are synthesized by soft-templating lignin nano- and microbeads bound with cellulose nanofibrils (CNFs). The interparticle connectivity and nanoscale network in the SPs are studied after oxidative thermostabilization of the lignin/CNF constructs. The carbon SPs are formed by controlled sintering during carbonization and develop high mechanical strength (58 N.mm(-3)) and surface area (1152 m(2). g(-1)). Given their features, the carbon SPs offer hierarchical access to adsorption sites that are well suited for CO2 capture (77 mg CO2.g(-1)), while presenting a relatively low pressure drop (similar to 33 kPa.m(-1) calculated for a packed fixed-bed column). The introduced lignin-derived SPs address the limitations associated with mass transport (diffusion of adsorbates within channels) and kinetics of systems that are otherwise based on nanoparticles. Moreover, the carbon SPs do not require doping with heteroatoms (as tested for N) for effective CO2 uptake (at 1 bar CO2 and 40 degrees C) and are suitable for regeneration, following multiple adsorption/desorption cycles. Overall, we demonstrate porous SP carbon systems of low cost (precursor, fabrication, and processing) and superior activity (gas sorption and capture).

Automated summary

Carbon supraparticles with hierarchical porous structures are synthesized from lignin and cellulose nanofibrils. These carbon SPs exhibit high mechanical strength, large surface area, and excellent CO2 adsorption capabilities with low pressure drop, addressing limitations in mass transport and kinetics often found in nanoparticle-based systems. Additionally, the carbon SPs do not require heteroatom doping for effective CO2 uptake and can be easily regenerated for multiple adsorption/desorption cycles, making them cost-effective and highly efficient for gas sorption and capture.