Guojian Ren

This review summarizes the design strategies and sensing mechanisms of Ln-MOFs for highly sensitive and selective luminescence detection across environmental monitoring, biomedicine, food safety, and public security.

Salicylaldehyde, an essential chemical intermediate, is extensively utilized in pharmaceutical and fragrance industries. However, the excessive usage leads to environmental pollution and poses potential risks to human body. Hence, it is urgent to develop the effective sensor for the detection of salicylaldehyde (SAL). Herein, a new terbium(III)‐based coordination polymer (HNU‐90‐Tb) is constructed by the assembly of 4‐carboxytriphenylamine (HL) with Tb³⁺. Benefiting from the hydrophobic structure of HL, HNU‐90‐Tb exhibits remarkable stability in aqueous environments and is capable of maintaining structural integrity in pH range of 2–11. Notably, HNU‐90‐Tb enables quantitative detection of SAL through fluorescence quenching, achieving a low detection limit of 0.07 ppm and a rapid response time of just 30 s. HNU‐90‐Tb also shows excellent selectivity toward a variety of aldehyde analogs. The detection mechanism can be attributed to the combined inner filter effect and dynamic quenching mechanism.

Water pollution has become a global environmental problem, such as that caused by Pb(II). Therefore, there is an urgent need to develop multifunctional materials for Pb(II) monitoring and removal. Yet, developing bifunctional materials for sensitive detection and efficient removal of Pb(II) remain challenging. Here, a metal-organic gel (HNU-G4) was constructed for sensible responsive detection and efficient adsorption of Pb(II). The dry gel was obtained through the freeze-dried process and can be used for the Pb(II) detection via fluorescence quenching; the lowest limit of detection for Pb(II) is 0.766 ppb. Furthermore, HNU-G4 has an effective maximum adsorption capacity of 480.00 mg·g-1 for Pb(II) in water. Additionally, the gel demonstrates excellent recoverability and interference resistance, which can be used in the detection and recovery of actual reclaimed water samples to prevent secondary contamination. This study developed a bifunctional gel material for sensitive detection and effective removal of Pb(II) from water, providing a suggested strategy to tackle the heavy metal contamination problem.

摘要: 核能作为最环保的能源之一, 得到了快速的发展。在核能的利用过程中, 产生的含有大量放射性元素的核废水成为核能发展所需要面对的重要问题。其中, 核废水中放射性元素的处理仍然是一项重大挑战。本研究利用酰胺基功能化有机配体 H ₆ TPBTM 与 Zr ⁴⁺ 组装, 形成了金属有机凝胶 ( HNU‐G6 )。 HNU‐G6 在酸性和碱性条件下均表现出优异的稳定性, 同时对U(VI)/Pb(II)具有较好的吸附能力。采用经典的伪一阶和伪二阶动力学吸附模型对动力学吸附实验拟合分析。采用 Langmuir、Freundlich、Temkin 和 Dubinin‐Radushkevich (D‐R) 模型对等温吸附实验拟合分析。在最佳吸附条件下 (pH = 5, U(VI): 12 h, Pb(II): 3 h), HNU‐G6 对 U(VI) 和 Pb(II) 的最大吸附容量分别为 604.3 mg·g ⁻¹ 和 453.2 mg·g ⁻¹ 。 HNU‐G6 表现出良好的循环性, 这可归因于其丰富的酰胺基和未完全配位的羧基。此外, HNU‐G6 还能同时吸附高盐度核废水中的U(VI) 和 Pb(II), 吸附量分别是U(VI): 227.8 mg·g ⁻¹ ; Pb(II): 152.1 mg·g ⁻¹ 。这项工作为处理核废水提供了一种新的材料和可行的策略.

Persistent environmental colored compounds, resistant to biodegradation, accumulate and harm eco-systems. Developing effective methods to break down these pollutants is crucial. This study introduces Ag-MIL-101 (Ag-MIL-101) as a composite and reusable catalyst that efficiently degrades specific colored organic pollutants (COPs) like Methylene blue (MB), 4-Nitrophenol (4-NP), and 4-Nitroaniline (4-NA) using sodium borohydride at room temperature. The MIL-101 was synthesized using Terephthalic acid (TPA) derived from the degradation of Polyethylene Terephthalate (PET) plastic waste, with the assistance of zinc chloride. To further investigation, the kinetics of degradation reaction was studied under optimized conditions in the presence of Ag-MIL-101 as catalyst. Our results demonstrated the remarkable efficiency of the degradation process, with over 93% degradation achieved within just 8 min. The catalyst was characterized using FTIR, XRD, FESEM, and TEM. In this study, the average particle size of Ag-MIL-101 was determined using SEM and XRD analysis. These methods allow us to accurately and precisely determine the particle size. We determined the reaction rate constants for the degradation of each COP using a pseudo first-order kinetic equation, with values of 0.585, 0.597 and 0.302 min⁻¹ for MB, 4-NP, and 4-NA, respectively. We also evaluated the recyclability of the catalyst and found that it could be reused for up to three cycles with only a slight decrease in efficiency (10–15%). Overall, our findings highlight the promising application of Ag-MIL-101 as an effective catalyst for the degradation of COPs, emphasizing the importance of optimizing reaction conditions to achieve enhanced efficiency.

The measurement of temperature is indispensable in the fields of life, science, and industry. Fluorescence thermometers are attractive to researchers because of their advantages such as noncontact, high sensitivity, fast response, and excellent anti-interference. Here, a new coordination polymer (HNU-76) was synthesized by assembling Zn²⁺ with the H₃TCA ligand, a fluorescent molecule with an AIE behavior, which can be used as a fluorescence thermometer. At 100-210 K, the fluorescence intensity ratio of HNU-76 versus temperature conforms to an Arrhenius-type decay relationship (R² = 0.997), which can be the candidate for low-temperature sensing. In order to increase the sensing range, 4-[4-(dimethylamino)styryl] pyndine (DMSP) was successfully embedded on HNU-76, obtaining HNU-76⊃DMSP. The fluorescence intensity of HNU-76⊃DMSP conforms to an Arrhenius-type decay relationship (R² = 0.997) at 270-360 K versus temperature. HNU-76 can be used for fluorescence detection at low temperatures, due to the DMSP loading, and HNU-76⊃DMSP can serve as the temperature thermometer in a range of temperatures common. Both materials show good cyclability and have the potential to be used in fluorescence thermometers.

WLEDs have been widely used in lighting and display equipment due to their energy-saving and environment-friendly advantages, but it is still a great challenge to construct high-quality single-phase white light materials for the preparation of WLEDs. In this work, three Ln–MOFs (HNU-82–84) with the same structure were synthesized by assembling rare earth ions (Tb³⁺, Eu³⁺, La³⁺) and 4,4′,4′′-nitrilotribenzoic acid (H₃TCA) ligands. The structure and optical properties of the three compounds were investigated. Under the ultraviolet lamp, HNU-82–84 displays green light, red light, and blue light emission, respectively. Based on the RGB principle, aiming at the single-phase white material, the proportion of adding rare earth ions is reasonably adjusted to design and synthesize the Ln–MOF (Eu_0.015Tb_0.037La_0.148-TCA) with CIE chromaticity coordinates of (0.319, 0.344). In addition, the WLED was prepared by Eu_0.015Tb_0.037La_0.148-TCA and commercial LED lamps. Furthermore, HNU-82 has strong fluorescence emission and good water stability and can be used to detect nitrofurazone (NZF) and nitrofurantoin (NFT). The concentrations of the aqueous solutions of NZF and NFT had a well correlated linear relationship with the fluorescence quenching effect of HNU-82, and the detection limits were 6.60 × 10⁻⁷ mol L⁻¹ and 4.62 × 10⁻⁷ mol L⁻¹, respectively. Hence, HNU-82 also has potential as a fluorescent sensor for the detection of NZF and NFT in the aquatic environment.