Design of Zr-MOFs by Introducing Multiple Ligands for Efficient and Selective Capturing of Pb(II) from Aqueous Solutions

Abstract

The existence of lead ions seriously affects the quality of many metal products in metallurgical enterprises. Currently, the various methods of lead-ion removal tried by researchers will affect valuable metals in the removal process, thus resulting in low economic efficiency. In this study, a novel metal–organic framework adsorbent (UiO-FHD) which efficiently and selectively captures lead ions is developed by introducing multiple ligands. The maximum adsorption capacity of lead ions is 433.15 mg/g at pH 5. The adsorption process accords with the pseudo-second-order kinetic and the Langmuir isotherm models at room temperature. Thermodynamic experiments indicate that the removal of Pb(II) is facilitated by appropriate temperature reduction. The performance tests indicate that UiO-FHD maintains a high removal rate of 90.35% for Pb(II) after four consecutive adsorption–desorption cycles. The distribution coefficient of lead ions (26.7 L/g) shows that UiO-FHD has excellent selective adsorption for lead ions. It is revealed that the chelation of the sulfhydryl groups and the electrostatic interaction of the hydroxyl groups are the dominant factors to improve the removal rate of Pb(II) by density functional theory calculations. This study clarifies the value of self-designed novel organic ligands in metal–organic framework materials that selectively capture heavy-metal ions.

Tuning the Dual Active Sites of Functionalized UiO-66 for Selective Adsorption of Yb(III)

“…To further analyze isothermal data, Langmuir, Freundlich, and Temkin models are adopted. ,, As displayed in Figure b–d, the adsorption isotherms of Yb­(III) by these amino-grafted UiO-66s are closest to the Langmuir isotherm model, because correlation coefficients ( R 2 ) of Langmuir models are 0.9967 for UiO-66-COOH-TETA and 0.9966 for UiO-66-(COOH) 2 -ED, which are exactly higher than those of Freundlich and Temkin isotherm models. Therefore, it can be assumed that the adsorption behaviors are mainly dependent on the monolayer adsorption via the independent binding sites of materials. , In addition, the corresponding fitting parameters for three models are listed in Table . We can find that q e values of the Langmuir model are calculated as 168.07 mg/g for UiO-66-COOH-TETA and 204.92 mg/g for UiO-66-(COOH) 2 -ED, which are also quite close to the real experimental data.…”

“…Therefore, it can be assumed that the adsorption behaviors are mainly dependent on the monolayer adsorption via the independent binding sites of materials. 46,47 In addition, the corresponding fitting parameters for three models are listed in Table 2. We can find that q e values of the Langmuir model are calculated as 168.07 mg/g for UiO-66-COOH-TETA and 204.92 mg/g for UiO-66-(COOH) 2 -ED, which are also quite close to the real experimental data.…”

Single-step synthesis of prominently selective and easily regenerable POSS functionalized with high loadings of sulfur and carboxylic acids

“…Whether the uptake of PGMs by POSS-S-COOH is spontaneous and endothermic in nature as well as whether randomness evolves during adsorption, can be demonstrated from the adsorption thermodynamics. 48 Various thermodynamic parameters can be deduced using the following equations:…”

Synthesis of Highly Efficient and Recyclable Bimetallic Cox–Fe1–x–MOF for the Synthesis of Xanthan and Removal of Toxic Pb2+ and Cd2+ Ions

“…Heavy metals became one of the dangerous environmental problems due to increasing the factories in recent years, which led to increase the concentrations of these toxic metals in water and wastewater. − Heavy metals such as Cr 2+ , Cd 2+ , Cu 2+ , and Pb 2+ are very toxic and introduce in ecosystems through industrial wastewaters during the chemical manufacturing, oil refining, alloy manufacturing, leather tanning, and battery manufacturing. , The dangerous effects of these metal ions on human beings’ health and ecological systems resulted due to the biomagnification property of these metal ions in the human body throughout the food chain, causing a variety of diseases and disorders when the human is exposed to it for a long time. ,− So, it is important to eliminate the toxic metals that resulted from industrial wastewater before disposal to the environment. Different methods have been reported for the removal of these toxic metals including ion exchange, ultrafiltration, adsorption, reverse osmosis, etc. However, the adsorption technique is considered one of the most preferred techniques due to its advantages as low cost, simplicity, and high efficiency. , Various materials have been applied as adsorbents for the removal of heavy metals such as modified MCM-41, zeolite, activated carbon, etc.…”

“…2,30−32 metals that resulted from industrial wastewater before disposal to the environment. Different methods have been reported for the removal of these toxic metals including ion exchange, ultrafiltration, 30 adsorption, 33 reverse osmosis, 30 etc. However, the adsorption technique is considered one of the most preferred techniques due to its advantages as low cost, simplicity, and high efficiency.…”