https://doi.org/10.1016/j.ccst.2022.100059
“Compared to above solid adsorbents, biochar is a kind of material which is insoluble, stable, highly aromatized and carbon-rich (Y. Lee et al., 2020). The International Biochar Initiative (IBI) defines biochar as being derived from the thermochemical combustion of biomass in an oxygen-limited environment (Lee et al., 2018). As the source of biochar, biomass generally contains various waste materials from agricultural wastes, such as wood chips, peanut shells, straw and wood scraps, industrial organic waste, and urban sludge (Rehman et al., 2017; Martín Juárez et al., 2018; Alakoski et al., 2016; Romero Millán et al., 2019; Li et al., 2020). Carbon, hydrogen, oxygen, and nitrogen are the primary components of biochar, with carbon accounting for more than 40% of the total elements (Xue et al., 2022). Biochar differs from traditional charcoal since biochar is intended for carbon storage and environmental applications, while charcoal is a charred product from biomass used as a fuel and energy source (Steiner et al., 2010; Li et al., 2021). Biochar prepared from different raw materials and pyrolysis conditions of biomass generally exhibits different physicochemical properties in terms of pore structures, specific surface areas, surface oxygen-containing functional groups and elemental compositions. Consequently, it could be employed in various aspects according to its distinct properties, such as adsorbents, soil amendments, catalysts, electrode materials (Nguyen and Lee, 2016; Mulabagal et al., 2015; Goldfarb et al., 2017; Lee et al., 2017). On account of its excellent surface structure, biochar can be used as an effective CO2 adsorbent and a promising alternative to replace conventional solid carbon-based catalysts which are economically and environmentally unfriendliness (Lee et al., 2017). Currently, Many investigations have been conducted to improve the physical and chemical properties of raw biochar using physical and chemical processes in order to produce modified biochar (Mian and Liu, 2020; Shafeeyan, 2010; Sizmur et al., 2017), which can be of great help in improving the adsorption capacity.”