Adsorption of CO2 by nitrogen doped corn straw based biochar

Three kinds of nitrogen dopants were used to prepare different nitrogen doped porous modified biochar from agricultural waste corn straw. The effects of three kinds of modified corn straw based biochar materials on CO2 removal performance under different conditions were studied, and the interaction mechanism of different nitrogen doped modified corn straw based biochar with CO2 was discussed. The results showed that: under normal temperature and pressure (25 °C and 1 bar), only carbamide (Urea) doping could improve the CO2 adsorption capacity of corn straw based biochar, but not reduce its low pressure (0.15 bar) adsorption capacity and CO2/N2 selectivity. The CO2 absorption of the porous carbon prepared by carboamide is 7.03 mmol/g at 0 °C and 4.97 mmol/g at 25 °C, and it has good recycling performance. The absorption at 25 °C is higher than that of all the porous biomass based carbon materials from lignocellulose biomass, animal manure, polymer, and petroleum coke. This study provides a new research direction for global greenhouse gas emission reduction and rational resource utilization of agricultural waste. © 2021, Saudi Society for Geosciences.