Preparation of UiO-66-NH2 and UiO-66-NH2/sponge for adsorption of 2,4-dichlorophenoxyacetic acid in water.

MOFs are usually used as efficient adsorbents to remove specific pollutants in water. However, because of their poor water stability relatively small particle size, their application in adsorbing and removing pollutants from water is limited. In this paper, with nitrile rubber sponge as the substrate, UiO-66-NH2/sponge composites were firstly in-situ synthesized and systematically evaluated UiO-66-NH2 as an adsorbent to remove 2,4-dichlorophenoxyacetic acid from water. This composite could not only remain the adsorption capacity for 2,4-dichlorophenoxyacetic acid of UiO-66-NH2, but also was much more convenient for separation after the adsorption compared to UiO-66-NH2. In addition, the mechanism of the adsorption of UiO-66-NH2 for 2,4-dichlorophenoxyacetic acid were discussed in detail. Electrostatic interaction between UiO-66-NH2 and 2,4-dichlorophenoxyacetic acid was the main adsorption mechanism. The adsorption was mainly suitable for Langmuir isotherm models, and its maximum adsorption capacity of 2,4-dichlorophenoxyacetic acid was 72.99 mg g-1.

Highly efficient removal of quinolones by using the easily reusable MOF derived-carbon.

As anthropogenic antibiotics, quinolones, e.g., ofloxacin have adverse impacts on ecological systems and human heaths. The removal of quinolones is of great importance, and adsorption techniques have been widely used to remove this hazardous contaminant. However, a robust and easy-operating adsorbent is still emergently required due to the complex chemical structure of quinolones. In this study, we successfully synthesized the promising metallic carbons (MCs) containing carbon nanotubes and cobalt nanoparticles by carbonizing Zn/Co-ZIF at 900 °C. Three different molar ratios of Co and Zn were applied to optimize the adsorption capacity on ofloxacin (OFL). Results showed MC with molar ratio of Co and Zn at 3:1 (Co-CNT/NPC3/1) achieved the maximal adsorption capacity to 118.3 mg g-1. Its adsorption performance was satisfied in the pH range from 5 to 9 and ionic strengths at 0.01 M. The main mechanisms for these adsorptions were identified as electrostatic attraction, metal coordination and π-π EDA. Removal efficiencies of quinolones higher than 68 mg g-1 indicated the strong feasibility of this adsorbent for wastewater treatments. The regeneration of Co-CNT/NPC3/1 at 600 °C allowed its at least 4-time reusability and its magnetic property enabled external magnets to recycle it from real environments.