Adsorption via sorbents is considered an attractive technology that can effectively separate CO₂ from flue gas. Optimal adsorption performance can be achieved through the utilization of specific sorbents with superior CO₂ adsorption capacity. This work demonstrates the conversion of water caltrop shell into N-doped porous carbons for CO₂ capture, which involves a three-step procedure, i.e., carbonization of water caltrop shell, post-nitriding by melamine, and KOH activation. The developed adsorbents possess plentiful porous structures and high nitrogen content, with BET surface area up to 2384 m² g⁻¹ and N content of 8.48 wt%, respectively. CO₂ adsorption measurements show that the studied sorbents have good CO₂ adsorption abilities, as high as 4.22 and 6.06 mmol g⁻¹ at 25 and 0 °C under ambient pressure, respectively. A comprehensive investigation found that CO₂ uptake of as-synthesized adsorbents is dictated by the synergistical interplay of N content and narrow microporous volume. Additionally, they exhibit fast CO₂ adsorption kinetics, excellent reversibility and stability, good CO₂/N₂ selectivity, applicable heat of adsorption and high dynamic CO₂ adsorption capacity. This work provides a general method of the preparation of N-doped porous carbonaceous sorbents from waste biomass. The inexpensiveness precursors along with simple preparation procedure highlight the great potential of biomass-based carbons in CO₂ capture and many other applications.

通过吸附剂的吸附被认为是一种有吸引力的技术，可以有效地将CO ₂与烟气分离。通过利用具有出色CO ₂吸附能力的特定吸附剂，可以实现最佳吸附性能。这项工作演示了将菱角壳转化为N掺杂的多孔碳以进行CO ₂捕集，该过程涉及三个步骤，即菱角壳的碳化，三聚氰胺的后氮化和KOH活化。所开发的吸附剂具有丰富的多孔结构和高氮含量，BET表面积分别高达2384 m ²  g ^-1和N含量为8.48 wt％。一氧化碳₂吸附测量结果表明，所研究的吸附剂具有良好的CO ₂吸附能力，分别在环境压力25和0°C时分别高达4.22和6.06 mmol g ^-1。全面的调查发现，合成态吸附剂对CO _2的吸收是由氮含量和狭窄的微孔体积的协同相互作用决定的。此外，它们还具有快速的CO ₂吸附动力学，优异的可逆性和稳定性，良好的CO ₂ / N ₂选择性，适用的吸附热和高动态CO ₂吸附能力。这项工作提供了从废物生物质中制备N掺杂的多孔碳质吸附剂的一般方法。廉价的前体以及简单的制备过程凸显了基于生物质的碳在CO ₂捕获和许多其他应用中的巨大潜力。