Efficient nitrogen doped porous carbonaceous CO adsorbents based on lotus leaf.

In this work, the waste biomass lotus leaf was converted into N-doped porous carbonaceous CO adsorbents. The synthesis process includes carbonization of lotus leaf, melamine post-treatment and KOH activation. For the resultant sorbents, high nitrogen content can be contained due to the melamine modification and advanced porous structure were formed by KOH etching. These samples were carefully characterized by different techniques and their CO adsorption properties were investigated in detail. These sorbents hold good CO adsorption abilities, up to 3.87 and 5.89 mmol/g at 25 and 0°C under 1 bar, respectively. By thorough investigation, the combined interplay of N content and narrow microporous volume was found to be responsible for the CO uptake for this series of sorbents. Together with the high CO adsorption abilities, these carbons also display excellent reversibility, high CO/N selectivity, applicable heat of adsorption, fast CO adsorption kinetics and good dynamic CO adsorption capacity. This study reveals a universal method of obtaining N-doped porous carbonaceous sorbents from leaves. The low cost of raw materials accompanied by easy synthesis procedure disclose the enormous potential of leaves-based carbons in CO capture as well as many other applications.