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.