Construction of HAnW-based nanotwigs for removing inorganic fluorion in wastewater

The environmental pollution with fluoride compounds was currently being paid more and more attention as it threatens the safety of animal and human life in an ecosystem. In this study, an eco-friendly adsorbing material for removing fluoride ion (F^-) was prepared by hydroxyapatite nanowires (HAnWs), a typical biocompatible inorganic conjugates. UiO66, a typical zirconium-based metal-organic framework (MOF), was conjugated onto HAnW by a simple in situ hydrothermal reaction, which afforded a novel HAnW-based nanotwigs of conjugates like millet (UiO66@HAnWs). Being characterized by SEM, EDS, FT-IR, XRD, XPS, and TGA, the obtained UiO66@HAnWs were applied to removing F^- in wastewater, and its adsorption capacity was optimized. It was found that UiO66@HAnWs had a bigger specific surface area (115.310 m²/g), and its efficiency for removing F^- got to 99.3%, which was greatly improved than that of related materials. It was considered that the adsorption of F^- on UiO66@HAnWs was mainly multi-molecular layer adsorption, which fluoride ions aggregate on the Zr(IV) active sites to attain ligand switching, and the nanoconjugated structure like nanotwigs of millet greatly improved its adsorption capacity. In summary, a novel eco-friendly UiO66@HAnWs with nanoconjugated structure could be constructed by simple hydrothermal method, which the agglomeration defects of MOFs were not only ameliorated, but also its adsorption capacity was greatly improved.

The Fluorescence Property of Zirconium-Based MOFs Adsorbed Sulforhodamine B

Sulforhodamine B (SRB) is widely utilized for cell staining and laser field. But its application is limited by aggregation-caused quenching (ACQ). In this work, we evaluated the use of UiO-66 and UiO-67 of Zr-based metal organic frameworks (Zr-MOFs) as the host to adsorb SRB molecules due to the high stabily and good loading capacity of Zr-MOFs. The fluorescence properties of the compounds were then discussed respectively. Due to the aperture difference between UiO-66 and UiO-67, they showed distinct fluorescence properties after loading SRB. When the concentration reaches 5 ppm, fluorescence quenching begins to occur in SRB@UiO-66, while it occurs in SRB@UiO-67 at 2 ppm. The solution of quenching phenomenon could open new avenues for the extensive use of SRB.