Heavy metal ions of Pb­(II) and Cd­(II) have become the global health and environmental concerns. NH2-functionalized Zr-MOFs were prepared via a rapid microwave-promoted synthesis and first used in the adsorptive removal of both Pb­(II) and Cd­(II). The nanosized (<100 nm) Zr-MOFs had an XRD pattern of UiO-66-NH2. Effects of adsorption time, temperature, pH, and initial ions concentration were studied on the adsorption of Pb­(II) and Cd­(II) onto the Zr-MOFs. The absorption results showed that the removal of Pb­(II) was 99.95% after 120 min at temperature of 30 °C and pH of 6 with an initial concentration of 10 mg·L–1. And the adsorption capacity of Cd­(II) achieved 177.35 mg·g–1 at an initial concentration of 40 mg·L–1. The adsorption fit the pseudo second-order kinetic model well and the mechanism was confirmed mainly as a coordination interaction between the amino group (−NH2) and Pb­(II) or Cd­(II). The NH2-functionalized Zr-MOFs have been proven to show good performance in the removal of heavy metal ions as an efficient adsorbent.

No abstract

No abstract

First-principles calculations based on periodic density functional theory (DFT) have been used to investigate the geometries, electronic structures, magnetic properties and diffusion behaviors of different noble metal adatoms (Pd, Pt, Cu, Ag and Au) on MoS monolayers. The results demonstrate that these adatoms can chemically adsorb on MoS monolayers. The band gaps of MoS monolayers with a Pd or Pt atom adsorbed are reduced owing to impurity states that emerge simultaneously within the gap region of the pristine MoS monolayer. The unpaired electrons in MoS monolayers with a Cu, Ag or Au atom adsorbed are spin polarized, resulting in total magnetic moments of 1.0 μ per supercell, which is caused by the strong hybridization between the metal adatoms and surrounding Mo or S atoms. Long-range antiferromagnetic (AFM) coupling has been observed between group IB metal adatoms. Due to charge transfer between adatoms and the MoS host, the work functions were modulated upon adsorption of noble metals. In addition, the diffusion behaviors of noble metal adatoms on the MoS monolayer suggest that Cu, Pd and Pt atoms favor the formation of a metal nanotemplate on the MoS monolayer, and Ag and Au are likely to form isolated particles in the initial growth stage. These findings may provide useful guidance to extend the potential applications of MoS in low-dimensional nanoelectronic and spintronic devices.

No abstract