Acetone adsorption on activated carbons: Roles of functional groups and humidity

Activated carbon (AC) materials has been widely used to prevent acetone pollution. In such process, the modification of AC is an effective way to improve the adsorption capacity of acetone. Therefore, the understanding of modification mechanism is the first and the most critical step in optimizing the preparation design and application of AC. A series of grand canonical Monte Carlo (GCMC) simulations was performed with models that were constructed from a collection of flat coronene-shaped graphitic basic units to systematically investigate the effect of different functional groups (i.e., OH, COOH, =O, NH₂, and NO₂) in the presence or absence of humidity. The AC isotherms obtained from the simulation model were well consistent with those obtained from experiments based on the premise that ACs had similar surface areas. Our results demonstrated that different functional groups under the same condition provided different non-electrostatic contribution and electrostatic contributions to acetone adsorption capacity. The electrostatic contribution of oxygen-containing functional groups was better than that of nitrogen-containing functional groups, and functional groups containing oxygen and hydrogen were better than the functional groups containing only oxygen. Humidity resulted in the pronounced decrease in the non-electrostatic contribution to all functional groups. However, electrostatic contribution under humidity is less affected by humidity.