Development of nitrogen-rich hierarchical porous carbon for high selective adsorption of methanol in multi-VOCs waste gas recovery processes

Abstract

Methanol is a typical polar volatile organic compound that has been commonly used as a solvent in industrial processes and is considered as an important resource. It often appears with aromatic compounds in practical application scenarios. Conducting methanol and aromatic compounds recycle technology can provide us with a sustainable carbon source for fuels and materials well beyond the fleeting fossil fuel era. Post-synthesis modification (PSM) has been utilized to incorporate 3-amino-1,2,4-triazole (Atz) into ZIF-8, thereby enabling the derivation of mesopore structure and enhancement of nitrogen content in ZIF-8 derived carbon. With this method the obtained carbon exhibited a highly polarizable micro-mesoporous structure, resulting in high adsorption capacity for methanol adsorption at low concentrations. The experimental results showed that the VOCs adsorption on porous carbon is primarily dictated by its microporous structure at high pressure, and predominantly governed by the presence of nitrogen functional groups and the micro-mesoporous properties at low pressure. DFT theoretical analysis also showed that nitrogen functional group can improve the absorption capacity of methanol by adsorbents through changing the electron distribution and surface polarity of carbon-based materials. Finally, based on the emission properties that is low concentration and high volume of VOCs waste gas in industrial application, ZIF8-24-700 and BACs-36 materials (Wang et al., 2023) were used to further prove the feasibility of this technology under low VOCs concentration, which achieve recovery rates of 99 % for toluene and 95 % for methanol, respectively.