Effective toluene adsorption over defective UiO-66-NH2: An experimental and computational exploration

In this thesis, defective UiO-66-NH 2 using cetyltrimethylammonium bromide (CTAB) as a template was successfully synthesized. The toluene adsorption-desorption properties were studied using breakthrough experiments and temperature programmed desorption (TPD). Modified UiO-66-NH 2 showed a high toluene increase due to the increased specific surface area and total pore volume and extra accessible adsorption sites generated by defects. Additionally, adsorption mechanisms were discussed at micro and molecule levels in light of density functional theory (DFT) calculations. By calculation, the amino hydrogen bonding gave rise to a higher toluene adsorption over UiO-66-NH 2 . In terms of the modified UiO-66-NH 2 with the most deficiencies, synergistic effects among π-π, -NH 2 , OH-CH 3 and OH-π hydrogen bonding strength also significantly intensified toluene adsorption. Furthermore, it could be noted that the OH-π interaction was stronger than the two bonded μ 3 -OH mechanisms. Notably, TPD and binding energies (BEs) depicted that defective UiO-66-NH 2 had a weaker toluene affinity than did UiO-66-NH 2 . Thus, gas toluene was easy to desorb with defective UiO-66-NH 2 at 298 K under atmospheric pressure. Finally, the repetitive regeneration experiment showed that the reproducibility of the materials was excellent.