Enhanced adsorption performance of UiO-66 via modification with functional groups and integration into hydrogels.

University of Oslo-66 (UiO-66) was a potential adsorbent for removing various pollutants from wastewater. Modifying the UiO-66 surface with different functional groups could enhance the adsorption performance. In this study, the UiO-66 modified with a functional group of -NH2 or -NO2 was prepared and tested to adsorb different pollutants. The results showed that -NO2 modified UiO-66 increased the adsorption capacity of tetracycline by 17 times to 94.08 mg g-1 compared with unmodified UiO-66. The adsorption process of UiO-66-NO2 followed the pseudo-second-order adsorption kinetic model and Langmuir isotherm model with a maximum isotherm adsorption capacity of 127.32 mg g-1. The adsorption interaction was hydrogen bonding and electrostatic attraction. The UiO-66-NO2 also showed good adsorption performance to Co2+, Methylene blue, Congo red. Fixing UiO-66-NO2 into hydrogel performed a stable absorption performance with a high absorption capacity (71.56 mg g-1) to TC and a good regeneration rate (85%) after five cycles, providing a novel applicable way to remove pollutants from wastewater.