Adsorption performance and mechanism analysis of HNO3-modified biomass-based zeolite templated carbon for benzothiophene in biodiesel

• The adsorption of BT by Bio-ZTC-M involved both physical and chemical mechanisms. • Carbonization temperature and holding time have a significant impact on the ADS performance of Bio-ZTC-M. • At 20°C, the adsorption of BT in biodiesel by Bio-ZTC-M is completed within 30 seconds. • Appropriately increasing the proportion of ultramicropores (0.65-1 nm) is beneficial to the adsorption of BT. In recent years, most countries have imposed stricter standards on the sulfur content in fuel oils. Thiophene compounds, predominantly benzothiophene (BT) and dibenzothiophene (DBT), are difficult to remove from biodiesel derived from waste cooking oil. Adsorption desulfurization using activated carbon is regarded as a potential solution. But the removal efficiency of common activated carbon for thiophene could not meet the requirement. Therefore, it is important to develop a carbon material that is highly efficient and selective. This study used tobacco stalks as carbon precursors and zeolite as a templating agent to prepare biomass-based zeolite templated carbon (Bio-ZTC). Subsequently, HNO 3 was used to modify its pore size and surface functional groups, resulting in a material (Bio-ZTC-M) with abundant hierarchical pore structures and surface functional groups. The adsorption performance and mechanism of Bio-ZTC-M for BT in biodiesel were investigated through characterization techniques, adsorption kinetics and molecular dynamics analyses. Under the optimal conditions, the removal efficiency of Bio-ZTC-M for BT in biodiesel reaches 68.07 % within 30 s at 20°C. In the process of BT adsorption by Bio-ZTC-M, both physical adsorption (π-π interactions and dipole-dipole interactions) and chemical adsorption (Lewis acid-base interactions) coexist. Furthermore, increasing the proportion of ultramicropores (0.65-1 nm) and mesopores in carbon materials is beneficial to the adsorption of BT.