The performance and mechanism of U(VI) removal from aqueous solutions by a metal–organic framework (DUT-69)

A zirconium-based metal–organic framework (DUT-69) was fabricated via a hydrothermal synthesis for U(VI) removal in aqueous solutions. Experimental results showed that the maximum adsorption capacity for U(VI) was 362.32 mg·g−1 at 303 K, pH = 6 and initial U(VI) concentration of 80 mg L−1. The adsorption process fit well with the pseudo-second-order kinetic and Langmuir models. Various characterizations indicated that complexation interactions was the central adsorption mechanism and electrostatic was the secondary. The carboxyl, Zr–O, and C–S bonds in the framework participated in the adsorption process. Reusability experiments showed that 80.34% adsorption rate could be maintained after 5 cycles.