Search

CN-121972146-A - Thiourea-bithiophene difunctional zirconium-based MOF adsorbent and preparation method and application thereof

CN121972146ACN 121972146 ACN121972146 ACN 121972146ACN-121972146-A

Abstract

The invention relates to a thiourea-bithiophene difunctional zirconium-based MOF adsorbent and a preparation method and application thereof, belonging to the technical field of environmental functional materials and water pollution control. The invention uses 4-carboxyphenylthiourea and [2, 2-bithiophene ] -5, 5-dicarboxaldehyde as ligand raw materials, and synthesizes Zr-MOF adsorbent with thiourea-bithiophene double-function site through solvent thermal method with zirconium tetrachloride, which is marked as Zr-THBD, and the structural formula is . The thiourea-bithiophene difunctional zirconium-based MOF adsorbent can be used for efficiently and selectively recovering gold ions (Au (III)) from acidic complex wastewater, and has excellent adsorption capacity and strong cyclic regeneration capacity.

Inventors

  • WANG SHIXING
  • YUAN HONGKUN

Assignees

  • 昆明理工大学

Dates

Publication Date
20260505
Application Date
20260320

Claims (8)

  1. 1. A thiourea-bithiophene difunctional zirconium-based MOF adsorbent is characterized in that 4-carboxyphenylthiourea and [2, 2-bithiophene ] -5, 5-dicarboxaldehyde are used as ligand raw materials, and the Zr-MOF adsorbent with thiourea-bithiophene difunctional sites, which is synthesized with zirconium tetrachloride through a solvothermal method, is recorded as ZR-THBD and has the structural formula: 。
  2. 2. The method for preparing the thiourea-bithiophene difunctional zirconium-based MOF adsorbent as claimed in claim 1, which is characterized by comprising the following specific steps: (1) Dissolving 4-carboxyphenylthiourea and [2, 2-bithiophene ] -5, 5-dicarboxaldehyde in ethanol, adding a catalyst acetic acid, and reacting for 18-24 hours at a constant temperature of 70-80 ℃ under stirring conditions to obtain a thiourea-bithiophene dual-function ligand; (2) Dissolving zirconium tetrachloride and a difunctional ligand of thiourea-bithiophene in N, N-dimethylformamide, adding hydrochloric acid, carrying out ultrasonic mixing to obtain a mixed solution, transferring the mixed solution into a high-pressure reaction kettle, reacting for 10-12 hours at the temperature of 130-140 ℃ under the stirring condition, carrying out solid-liquid separation, washing the solid by absolute ethyl alcohol and deionized water alternately until eluent is colorless, carrying out vacuum drying, and grinding to obtain the Zr-MOF adsorbent Zr-THBD.
  3. 3. The preparation method of the thiourea-bithiophene difunctional zirconium-based MOF adsorbent is characterized in that the molar ratio of the 4-carboxyphenylthiourea to the [2, 2-bithiophene ] -5, 5-dicarboxaldehyde in the step (1) is 1-2:1.
  4. 4. The method for preparing the thiourea-bithiophene difunctional zirconium-based MOF adsorbent, according to claim 3, wherein the concentration of 4-carboxyphenylthiourea in the mixed solution in the step (1) is 0.05-0.08 mol/L.
  5. 5. The preparation method of the thiourea-bithiophene difunctional zirconium-based MOF adsorbent is characterized in that the adding amount of acetic acid in the step (1) is 10-12 mL/L.
  6. 6. The preparation method of the thiourea-bithiophene difunctional zirconium-based MOF adsorbent is characterized in that the molar ratio of zirconium tetrachloride in the step (2) to 4-carboxyphenylthiourea in the step (1) is 1-2:2.5.
  7. 7. The preparation method of the thiourea-bithiophene difunctional zirconium-based MOF adsorbent is characterized in that the concentration of zirconium tetrachloride in the mixed solution in the step (2) is 0.05-0.1 mol/L, and the addition amount of hydrochloric acid is 1.5-2 mL/L.
  8. 8. The use of the thiourea-bithiophene bifunctional zirconium-based MOF adsorbent of claim 1 for selectively adsorbing Au (III) in acidic wastewater.

Description

Thiourea-bithiophene difunctional zirconium-based MOF adsorbent and preparation method and application thereof Technical Field The invention relates to a thiourea-bithiophene difunctional zirconium-based MOF adsorbent and a preparation method and application thereof, belonging to the technical field of environmental functional materials and water pollution control. Background The current method for recovering Au (III) in wastewater mainly comprises a chemical precipitation method, a solvent extraction method, an electrolysis method, a membrane separation method, an adsorption method and the like. The adsorption method has the most application prospect because of flexible operation, low energy consumption, easy realization of high selectivity and anti-interference performance. However, conventional adsorbent materials (activated carbon, molecular sieves, functionalized resins, etc.) suffer from a number of drawbacks. The metal organic framework Materials (MOFs) become ideal platforms for constructing high-performance adsorption sites due to clear crystal structure, high specific surface area, accurate and controllable aperture and functional design of surface chemistry, and can realize specific identification and capture of target metal ions through 'pore structure engineering' and 'site engineering'. However, the conventional MOF-based adsorbent still has the key problems that ① functional sites are single in design, high adsorption capacity and excellent selectivity are difficult to realize simultaneously, the selectivity of the MOF-based adsorbent to AuCl 4- in complex water bodies containing a large amount of competitive ions is insufficient, and most MOFs of ② are insufficient in chemical stability in actual wastewater environments such as strong acid, high salt and the like, are easy to generate structural degradation and severely limit industrial application. Disclosure of Invention Aiming at the problems of low adsorption capacity, poor selectivity, insufficient stability, poor cycle performance and the like of the existing Au (III) adsorbent and the defects of single design of functional sites and easy degradation in a strong acid environment of the existing MOF-based adsorbent, the invention provides the thiourea-dithiophene difunctional zirconium-based MOF adsorbent and the preparation method and application thereof, and the high-stability Zr-MOF adsorbent (Zr-THBD) is constructed by reasonably designing and integrating ligands of thiourea-dithiophene difunctional units and Zr 4+ clusters, so that the high-efficiency and high-selectivity adsorption of Au (III) in acidic wastewater is realized. Thiourea (-NH-CS-NH-) is a strong Lewis basic bidentate ligand, S, N atoms of which have specific strong coordination and reduction capability on gold and complexes thereof, and bithiophene units are used as an electron-rich aromatic system, so that the conjugation and chemical stability of the ligand can be enhanced, and the enrichment of gold species is assisted by the action of sulfur-pi. The two are integrated into a double-function ligand, and the MOF material is constructed by combining high-stability Zr 4+ clusters of metal nodes, so that the site synergistic enhancement effect can be realized, the structural integrity of the material in an extreme chemical environment is ensured, and a new way is provided for solving the technical bottleneck of the existing MOF-based adsorbent. A thiourea-bithiophene difunctional zirconium-based MOF adsorbent takes 4-carboxyphenylthiourea and [2, 2-bithiophene ] -5, 5-dicarboxaldehyde as ligand raw materials, and is synthesized with zirconium tetrachloride through a solvothermal method, and the Zr-MOF adsorbent with thiourea-bithiophene difunctional sites is recorded as ZR-THBD, and has the structural formula: 。 The preparation method of the thiourea-bithiophene difunctional zirconium-based MOF adsorbent comprises the following specific steps: (1) Dissolving 4-carboxyphenylthiourea and [2, 2-bithiophene ] -5, 5-dicarboxaldehyde in ethanol, adding a catalyst acetic acid, and reacting for 18-24 hours at a constant temperature of 70-80 ℃ under stirring conditions to obtain a thiourea-bithiophene dual-function ligand; (2) Dissolving zirconium tetrachloride and a difunctional ligand of thiourea-bithiophene in N, N-dimethylformamide, adding commercial hydrochloric acid, carrying out ultrasonic mixing to obtain a mixed solution, transferring the mixed solution into a high-pressure reaction kettle, reacting for 10-12 hours at the temperature of 130-140 ℃ under the stirring condition, carrying out solid-liquid separation, washing the solid by absolute ethyl alcohol and deionized water alternately until the eluent is colorless, carrying out vacuum drying, and grinding to obtain the Zr-MOF adsorbent Zr-THBD. The reaction process is as follows: 。 preferably, the molar ratio of the 4-carboxyphenylthiourea in the step (1) to the [2, 2-bithiophene ] -5, 5-dicarboxaldehyde is 1-2:1.