Research on nonsteady-state adsorption and regulation towards stabler adsorption for benzene over single-wall carbon...

With the intention of separating benzene (C₆H₆) from indoor polluted air and collecting it in a cleaner way, it is promising of getting C₆H₆ adsorbed on activated carbon materials with outstanding physicochemical properties. In this study, how C₆H₆ is adsorbed over single-wall carbon materials and relevant adsorption processes are enhanced is thoroughly investigated via density functional theory (DFT). Especially, distinction between partial and whole effects of adsorbents on C₆H₆ adsorption, features of electron distribution across section of adsorption forms, and regulation mechanism of nonsteady-state adsorption for C₆H₆ are key points. According to calculation results, C₆H₆ molecules could be captured by pure single-wall carbon nanotube (CNT) through repulsive forces (quantified as 103.42 kJ/mol) from all quarters, which makes it stay in nonsteady-state adsorption forms and easily run into free state. Therefore, when external temperature increases from 0 to 300 K, molecular movement will be intense enough to help C₆H₆ break into another random positions instead of statistically remaining immobile. As for this problem, single-wall CNTs are modified through making defects and replacing some C atoms with N atoms, respectively. In this way, surficial electron distribution of modified adsorbents is regulated to tremendously cut down repulsive forces (quantified as 50.30 kJ/mol) and reverse nonsteady-state adsorption into near-equilibrium quasi-steady-state adsorption (single-side attraction near 100 kJ/mol). Therefore, this research would provide useful information for exploiting single-wall carbon materials as effective adsorbents of C₆H₆ in order to quickly achieve indoor air purification.