Insights into binding manners of a Fe doping MOF-808 in high-performance adsorption: A case of antimony adsorption

The full utilization of adsorption sites is crucial for adsorption technology. Metal-organic frameworks (MOFs), which are hot spot materials in environmental remediation, are not satisfied in many cases for their high specific surface area and relatively low adsorption capacity. In this work, a series of zirconium-iron bimetallic MOFs (ZrxFe(1-x)-MOF-808) was prepared. The optimal material (Zr0.8Fe0.2-MOF-808) possesses a superb adsorption capacity of 524 and 310 mg g–1 for antimonate and antimonite, respectively. The carboxyl and hydroxyl groups were identified as the main adsorption sites by FTIR and XPS. The role of Fe in the adsorption process of Zr0.8Fe0.2-MOF-808 were further explored by DFT simulations, four binding manners were discovered and consistent with the adsorption capacity data. Subsequently, the application potential tests proved that the Zr0.8Fe0.2-MOF-808 shows good anti-interference ability, wide pH adaptability, and recyclability. Overall, this high-performance bimetallic MOF has been analyzed from the macrocosm to microcosmic, which provides a certain support for the development of MOFs modification.