The development of metal ion detection probes with high sensitivity and selectivity is of utmost importance for the promotion of public health and environmental sustainability. In this work, a series of ratiometric fluorescent probes (RhB@UiO-67-NH 2 ) were successfully prepared using a one-pot method for the detection of metal ions, particularly As 5+ and Fe 3+ . Notably, the ratiometric fluorescent probe RhB@UiO-67-NH 2 (1:4) demonstrates dual functionality as a Fe 3+ turn-off probe and an As 5+ turn-on probe. The limits of detection (LODs) for As 5+ and Fe 3+ using RhB@UiO-67-NH 2 (1:4) were determined to be 0.521 μM (39.03 ppb) and 0.107 μM (5.97 ppb), respectively, which were the lowest records of reported LMOFs so far. The fluorescence quenching of Fe 3+ can be attributed to various mechanisms such as fluorescence resonance energy transfer (FRET), photoinduced electron transfer (PET), and competitive absorption (CA). Additionally, the fluorescence enhancement of As 5+ is primarily due to absorbance-caused enhancement (ACE) and PET. Moreover, the composite material RhB@UiO-67-NH 2 (1:4) exhibited excellent anti-interference capability and reproducibility for detecting Fe 3+ and As 5+ . The removal efficiency of As 5+ by RhB@UiO-67-NH 2 (1:4) exceeded 50.9 % when the initial concentration of As 5+ was below 20 mg/L. This work presents a valuable reference for future investigations and utilization of As 5+ and Fe 3+ sensing.
Haoyu Guan,Guoqiang Fang,Xinxin Li,Haoyu Dong,Siqingaowa Han,Xiang Lin,Li Wang
The plasmon coupling properties of assembled metal nanogap structures are highly sensitive to the distance, shape, orientation, and configuration of faceted nanoparticles. However, the orientation control of nanoparticles is usually limited to in-plane configurations. In this paper, Au@Ag nanocubes (NCs) with sharp edges and corners were assembled on a polystyrene (PS) microsphere array as a hierarchical surface-enhanced Raman spectroscopy (SERS) substrate via a facile self-assembly technique. The Au@Ag NC monolayer undergoes an out-of-plane reconstruction and forms V-shaped nanogaps under the modulation of the PS microsphere array curved surface. This unique V-shaped nanogap can generate electromagnetic fields stronger than those of traditional parallel gaps and make it easier for target molecules to diffuse into the nanogaps. The three-dimensional (3D) SERS substrates have a wider spectral response and 20 times higher SERS activity than those of the Au@Ag NC monolayer films on flat substrates. The high sensitivity was demonstrated by the detection limit down to 10–9 M for 4-MBA with a substrate enhancement factor up to 3.1 × 107. Furthermore, the optimized 3D SERS substrate was applied to determine As5+ in water with detection limits as low as 10–8 M assisted by machine learning, indicating that the 3D SERS substrates have promising applications in food safety, environmental monitoring, and biological diagnosis.
In this study, iron oxide (Fe3O4) was coated with ZrO2, and doped with three rare earth elements((Y/La/Ce), and a multi-staged rare earth doped zirconia adsorbent was prepared by using uniform design U14, Response Surface methodology, and orthogonal design, to remove As3+and As5+from the aqueous solution. Based on the results of TEM, EDS, XRD, FTIR, and N2-adsorption desorption test, the best molar ratio of Fe3O4:TMAOH:Zirconium butoxide:Y:La:Ce was selected as 1:12:11:1:0.02:0.08. The specific surface area and porosity was 263 m2/g, and 0.156 cm3/g, respectively. The isothermal curves and fitting equation parameters show that Langmuir model, and Redlich Peterson model fitted well. As per calculations of the Langmuir model, the highest adsorption capacities for As3+and As5+ions were recorded as 68.33 mg/g, 84.23 mg/g, respectively. The fitting curves and equations of the kinetic models favors the quasi second order kinetic model. Material regeneration was very effective, and even in the last cycle the regeneration capacities of both As3+and As5+were 75.15%, and 77.59%, respectively. Adsorption and regeneration results suggest that adsorbent has easy synthesis method, and reusable, so it can be used as a potential adsorbent for the removal of arsenic from aqueous solution.Keywords:magnetic Fe3O4;uniform design;surface response methodology;multi-staged doping;arsenic (III & V) removal
危险品化学品经营许可证（带存储）