Xiaoyan Duan,Kaiqiang Wang,Lei Wang,Limin Cao,Jianxin Sui,Hong Lin
In this study, a new metal-organic framework adsorbent (UIO-66-NH 2 @TA) which can efficiently and selectively capture lead ions was developed by functionalizing UIO-66-NH 2 with tannic acid (TA) by Michael addition reaction. The structural and morphological properties of the produced adsorbent, as well as its adsorption mechanism for Pb (II) were discussed. The maximum adsorption capacity of Pb (II) was 475.78 mg/g at pH 5.0, which was significantly higher than the adsorption capacity of many adsorbents reported in the literature. In addition, the adsorption isotherms and kinetics conformed to the Langmuir model and pseudo-second-order kinetic model , respectively. The results indicated that the adsorptive behavior of the adsorbent mainly depended on the active sites on the surface of the adsorbents. The UIO-66-NH 2 @TA showed favorable selectivity toward Pb (II) against the interference of coexisting metal ions . It was found that the excellent Pb (II) removal performance of UIO-66-NH 2 @TA was mainly attributed to the synergistic effect of physical adsorption and chemisorption . Moreover, the UIO-66-NH 2 @TA showed extraction efficiencies of 88.01%, 82.44%, 80.20% and 74.99% for Pb (II) with initial concentration of 100 mg/L in river water, sea water, peach juice drink, and grape juice, respectively. This work proved that the UIO-66-NH 2 @TA had a wide application prospect in the field of Pb (II) treatment.
Kaiqiang Wang,Xiaoyan Duan,Ye Tian,Hong Lin,Limin Cao,Jianxin Sui
In this work, a novel method for sensitive detecting heavy metal Pb (II) in aquatic products was developed using UiO-66-NH 2 @tannic acid (UiO-66-NH 2 @TA) solid-phase extraction combined with laser-induced breakdown spectroscopy (LIBS). UiO-66-NH 2 @TA adsorbent could effectively extract Pb (II) from the digestive solution of aquatic products. Characterization of the morphology of the adsorbent was performed using transmission electron microscopy and scanning electron microscopy. The optimal experimental conditions for LIBS detection, including sample preparation, substrate type, laser energy, and delay time, were investigated. The results showed that the strongest Pb I 405.7 nm spectral signal can be obtained by dripping UiO-66-NH 2 @TA adsorbent onto a silicon wafer for LIBS testing. The limit of detection and limit of quantification for Pb (II) in aqueous solution were 0.18 μg/mL and 0.61 μg/mL, respectively. The calibration curve demonstrated good sensitivity and accuracy for Pb (II) detection with a correlation coefficient of 0.9905. Spiked recovery experiments on large yellow croakers and scallops yielded recovery rates of 75.25 % - 99.08 %, which was consistent with the results from atomic absorption spectrometry. This study underscores the potential of the solid-phase extraction combined with laser-induced breakdown spectroscopy for practical application in food safety monitoring, demonstrating its effectiveness and reliability in detecting Pb (II) in aquatic products.
危险品化学品经营许可证（带存储）