Metal-center effect induced efficient charge transfer of metal-organic framework for strengthening Sb(V) capture performance

The adsorbents—adsorbates interaction is critical for resourcelization in heavy metal wastewater treatment. Nevertheless, it is still indistinct to depict the impact of metal center effect on heavy metals removal performance in metal-organic frameworks (MOFs)-based adsorbents. Herein, a series of MOFs with different metal centers of Mg(II), La(III), and Zr(IV) are rationally designed, and the effect of electronic structure on the Sb(V) removal performance is systematically investigated. The obtained La-MGs achieve Sb(V) adsorption capacity of 897.6 mg/g, which is about 1.2 and 4.5 times above average than those of Zr-MGs and Mg-MGs, respectively. On account of more edge adsorption sites achieve, the sites utilization efficiency of La-MGs (92.1%) is much better than Zr-MGs (75.0%) and Mg-MGs (20.4%). Furthermore, density functional theory (DFT) calculations reveal that La-MGs are more active than Mg-MGs and Zr-MGs, owing to the lower adsorption energy, higher charge transfer, and stronger bonding interaction, which will promote the Sb(V) removal performance. The experimental results in practical water indicate that La-MGs effectively capture antimony at low concentration, reaching drinking water standard in samples from Ganjiang River. This study opens an avenue for atomic-level insight into high-efficient absorbents design for water treatment from electronic structure-modification of active centers.