Porosity and Basicity Tuned Biomass-derived Activated Carbon Enhancing CO2 Capture

Abstract

The dual challenges of excessive carbon dioxide emissions and the accumulation of agricultural biomass waste pose significant environmental concerns. A sustainable solution lies in repurposing biomass derived materials for CO 2 mitigation. Biomass wastes are one of the primary sources for carbonaceous materials, and with a rational synthetic strategy, these substrates can be turned into a cost-effective solution for CO 2 capture. In this work, we develop a nitrogen doped activated carbon-based sorbent from peanut shells, optimizing its porosity and basicity for selective CO 2 adsorption. Peanut shell, a lignocellulose carbonaceous biomass, can be transformed into a porous, CO 2 specific adsorbent through a two-step synthesis. By optimizing porosity and basicity, peanut shell derived nitrogen doped activated carbon synthesised at 700 ℃ (PSNAC700) emerged as the best adsorbent, exhibiting exceptional uptake of 9.78 mmol/g in an ultra-dilute CO 2 stream (5000 ppm). Operando studies reveal the deformation in CO 2 geometry upon strong adsorbate-adsorbent interactions. Life cycle assessment (LCA) further validates the overall technology as carbon-negative, with an implementation of renewable energy source for regeneration and aligns with net-zero climate targets.