A zirconium-yttrium bimetallic MOF adsorbent, a preparation method and applications thereof

Abstract

This invention discloses a zirconium-yttrium bimetallic MOF adsorbent, its preparation method, and its applications. The preparation method includes: adding deprotonated 2-aminoterephthalic acid dropwise to a mixed solution containing zirconium chloride, yttrium chloride, and glacial acetic acid, stirring at room temperature to obtain the zirconium-yttrium bimetallic MOF adsorbent. The adsorbent is then added to water containing a certain concentration of As and / or P, and adsorbed by isothermal shaking to remove As and / or P from the water. This invention enhances the adsorption activity for As and / or P through the special coordination and electrostatic interactions between zirconium and yttrium bimetals and As and P. The zirconium-yttrium bimetallic MOF adsorbent prepared by this invention uses a green synthesis route with room temperature doping, requiring no high-temperature operation. The adsorbent can be reused, with minimal waste, and can remove As and / or P from water. It has low preparation and usage costs, is environmentally friendly, and has a wide range of applications.

Description

Technical Field

[0001] This invention relates to adsorption and removal technology of arsenic and / or phosphorus in water, belonging to the field of environmental science and engineering technology, specifically relating to a zirconium-yttrium bimetallic MOF adsorbent, its preparation method, and its application in removing arsenic and / or phosphorus from water. Background Technology

[0002] With the increasing severity of global phosphorus and arsenic pollution, the removal of phosphorus and arsenic from water bodies has been a hot topic in environmental science research. Lanthanum (La)-modified bentonite (LMB) "phosphorus-locking agent," developed by CSIRO in Australia, has successfully achieved large-scale and effective control of endogenous phosphorus in natural water body sediments. LMB forms an active passivation layer on the sediment surface, chelating with inorganic phosphorus released from the sediment, thus achieving endogenous phosphorus control. In recent years, adsorption methods have attracted widespread attention due to their advantages such as being environmentally friendly, easy to operate, and effective in removing low concentrations of arsenic and exogenous phosphorus. Traditional adsorbents such as mesoporous silica, iron oxide tailings, iron-based nanoparticles, anion exchange resins, and metal-organic frameworks (MOFs) have been widely used in the adsorption and removal of phosphorus or arsenic in water bodies. However, traditional adsorbents are mostly designed for the removal of single phosphorus or arsenic, and generally suffer from drawbacks such as low adsorption efficiency, poor selectivity, and difficulty in elution. Furthermore, the difficulty in reusing adsorbents leads to large amounts of waste residue and high costs, preventing the large-scale application of traditional adsorbents in the treatment of arsenic and phosphorus pollution. To address the problem of arsenic and / or phosphorus pollution in natural water bodies worldwide, there is an urgent need to develop novel adsorbents with large adsorption capacity, high selectivity, good reusability, low preparation and usage costs, which can be used for the removal of arsenic and / or phosphorus. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing materials for the simultaneous removal of phosphorus and arsenic by providing a zirconium-yttrium bimetallic MOF adsorbent (referred to as Y-UiO66-NH2) that requires a small amount of adsorbent and has a high removal efficiency for arsenic and / or phosphorus. Y-UiO66-NH2 not only has a large adsorption capacity for both arsenic and phosphorus, but also exhibits easy elution, reusability, minimal waste residue, and low treatment cost. It can be used for the simultaneous removal of arsenic and phosphorus from water, and has broad application prospects.

[0004] The objective of this invention is achieved through the following means:

[0005] A zirconium-yttrium bimetallic MOF adsorbent, denoted as Y-UiO66-NH2, is prepared by the following method: deprotonated 2-aminoterephthalic acid is added dropwise to a mixed solution containing zirconium oxychloride, yttrium chloride, and glacial acetic acid, using water as a solvent, and stirred at room temperature to obtain the zirconium-yttrium bimetallic MOF adsorbent Y-UiO66-NH2; the molar ratio of zirconium oxychloride, yttrium chloride, glacial acetic acid, 2-aminoterephthalic acid, and sodium hydroxide is 1:1:4:2:4.

[0006] A method for preparing a zirconium-yttrium bimetallic MOF adsorbent Y-UiO66-NH2, comprising:

[0007] A certain mass of zirconium oxychloride, yttrium chloride, and glacial acetic acid were added to pure water to obtain a mixed solution. Separately, a certain mass of 2-aminoterephthalic acid was dissolved in an appropriate amount of pure water, and then a certain mass of sodium hydroxide was added to prepare a deprotonated 2-aminoterephthalic acid solution. The prepared deprotonated 2-aminoterephthalic acid solution was added dropwise to the above mixed solution containing zirconium oxychloride, yttrium chloride, and glacial acetic acid. The mixture was stirred at room temperature for 10 hours. The resulting solid was washed once with water, then three times with ethanol, and dried in a vacuum drying oven at 60°C for 12 hours to obtain the zirconium-yttrium bimetallic MOF adsorbent Y-UiO66-NH2.

[0008] The molar ratio of zirconium oxychloride, yttrium chloride, glacial acetic acid, 2-aminoterephthalic acid, and sodium hydroxide is 1:1:4:2:4.

[0009] The method for removing As and / or P from water using Y-UiO66-NH2 of the present invention includes the following steps:

[0010] (1) Take a certain mass of Y-UiO66-NH2 at a solid-liquid ratio of 1:10 (g / L) and add it to an aqueous solution containing a certain concentration of As and / or P at pH = 6.0 to 8.8. Shake at 180 rpm and 25℃ for 8 to 15 min. Filter out Y-UiO66-NH2 loaded with As and / or P.

[0011] (2) Take Y-UiO66-NH2 loaded with As and / or P in step (1) above, and desorb the arsenic and / or phosphorus adsorbed on Y-UiO66-NH2 by constant temperature shaking at 180 rpm and 25℃ for 15 to 20 min with 0.1 to 0.3 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:0.1 g / L.

[0012] (3) Take the Y-UiO66-NH2 after desorbing arsenic and / or phosphorus in step (2) above, wash it twice with tap water, return to step (1), and adsorb the same aqueous solution containing arsenic and / or phosphorus again to realize the reuse of Y-UiO66-NH2.

[0013] Further, the concentration of the As solution in step (1) is 0.1 to 2.0 mg / L, and the concentration of P is 0.1 to 1.0 mg / L.

[0014] Further, after filtering out Y-UiO66-NH2 loaded with arsenic and / or phosphorus in step (1), the concentration of arsenic and / or phosphorus in the aqueous phase is further measured. The amount of arsenic and / or phosphorus adsorbed by Y-UiO66-NH2 is calculated by the difference method, and the adsorption rate is calculated.

[0015] Further, after step (2) is completed, the concentrations of As and / or P in the desorption solution are further determined, and the desorption rate of As and / or P is calculated.

[0016] The present invention has the following advantages and effects:

[0017] (1) The preparation of traditional MOF adsorbents requires high-temperature hydrothermal reaction. The zirconium-yttrium bimetallic MOF adsorbent Y-UiO66-NH2 adopts a green synthesis route of room temperature doping with rare earth elements. The preparation process of Y-UiO66-NH2 is simple and can be completed at room temperature. The preparation cost is low and it can be mass-produced.

[0018] (2) Y-UiO66-NH2 has a special affinity for arsenic and phosphorus, and has excellent adsorption performance for arsenic and phosphorus in aqueous solution. It can be used for the removal of arsenic and / or phosphorus in water.

[0019] (3) Y-UiO66-NH2 adsorbs arsenic and / or phosphorus in aqueous solution and is easy to elute. The adsorbent can be reused, which greatly reduces the amount of hazardous waste residue to be treated. It has low cost, is environmentally friendly and easy to promote and use on a large scale.

[0020] The above advantages can be seen from the experimental results of the maximum static adsorption capacity of the cycle and the data of Examples 1 to 9.

[0021] Static adsorption capacity

[0022] Weigh 0.1 g of Y-UiO66-NH2 as two portions as the stationary phase, and add them to 1.0 L of 0.60 g / L As or P aqueous solution at pH 7.0. Shake at 180 rpm and 25℃ for 2 h. Filter out the Y-UiO66-NH2 loaded with As or P respectively. Measure the adsorption capacity of As or P. Add the filtered Y-UiO66-NH2 loaded with As or P to 10 mL of 0.3 mol / L hydrochloric acid solution, shake for 30 min, filter out the Y-UiO66-NH2 in the desorption solution, wash the Y-UiO66-NH2 twice with tap water, and adsorb the same As or P solution again. The results of the maximum static adsorption capacity determination after 3 cycles are shown in Table 1.

[0023] Table 1. Determination of maximum static adsorption capacity during cycling

[0024]

[0025] As can be seen from Table 1, after three cycles of use, Y-UiO66-NH2 still has a strong adsorption capacity for As or P. Y-UiO66-NH2 has a large adsorption capacity, good stability, and can be recycled multiple times. Attached Figure Description

[0026] Figure 1 X-ray powder diffraction (XRD) patterns of UiO66-NH2 and Y-UiO66-NH2.

[0027] Figure 2 The diagram shows the nitrogen adsorption-desorption isotherms for UiO66-NH2 and Y-UiO66-NH2.

[0028] Figure 3 The XPS spectra of Y-UiO66-NH2 are shown, where: (a) is the full spectrum; (b) is the spectrum of Y 3d. Detailed Implementation

[0029] The preparation of the adsorbent of the present invention and its application in treating water containing As and / or P are described in detail below with reference to examples. The examples listed do not limit the scope of protection of the present invention.

[0030] Example 1

[0031] A method for preparing a zirconium-yttrium bimetallic MOF adsorbent involves adding 0.81 g of zirconium oxychloride (ZrOCl2·8H2O), 0.49 g of yttrium chloride (YCl3), and 0.60 g of glacial acetic acid to 50 mL of pure water to obtain a mixed solution. Separately, 0.905 g of 2-aminoterephthalic acid is dissolved in 50 mL of pure water, and 0.4 g of sodium hydroxide is added to prepare a deprotonated 2-aminoterephthalic acid solution. This deprotonated 2-aminoterephthalic acid solution is then added dropwise to the above mixed solution containing zirconium oxychloride, yttrium chloride, and glacial acetic acid. The mixture is stirred at room temperature for 10 hours. The resulting solid is washed once with water and three times with ethanol, and then dried in a vacuum drying oven at 60 °C for 12 hours to obtain the zirconium-yttrium bimetallic MOF adsorbent Y-UiO66-NH2.

[0032] Example 2

[0033] 1. Weigh 0.1 g of Y-UiO66-NH2 as the stationary phase and add it to 1.0 L of an aqueous solution containing 0.10 mg / L As at pH 6.0. Shake at 180 rpm and 25 °C for 8 min. Filter out the loaded Y-UiO66-NH2 and determine the concentration of As in the filtrate. Calculate the adsorption rate (E%) (experimental data are shown in Table 2).

[0034] 2. Add the filtered As-loaded Y-UiO66-NH2 to 10 mL of 0.1 mol / L hydrochloric acid solution for desorption. Shake at 180 rpm and 25 °C for 15 min. Filter out Y-UiO66-NH2, determine the As content in the hydrochloric acid desorption solution, and calculate the As desorption rate (S%) (experimental data are shown in Table 2).

[0035] Example 3

[0036] 1. Weigh 0.1 g of Y-UiO66-NH2 as the stationary phase and add it to 1.0 L of 0.10 mg / L aqueous solution with pH 6.5. Shake at 180 rpm and 25 °C for 10 min. Filter out the loaded Y-UiO66-NH2, determine the concentration of P in the filtrate, and calculate the adsorption rate (E%) (experimental data are shown in Table 2).

[0037] 2. Add the filtered P-loaded Y-UiO66-NH2 to 10 mL of 0.1 mol / L hydrochloric acid solution for desorption. Shake at 180 rpm and 25 °C for 16 min. Filter out Y-UiO66-NH2, determine the P content in the hydrochloric acid desorption solution, and calculate the P desorption rate (S%) (experimental data are shown in Table 2).

[0038] Example 4

[0039] 1. Weigh 0.1 g of Y-UiO66-NH2 as the stationary phase and add it to an aqueous solution of 1.0 L of 1.0 mg / L As at pH 7.0. Shake at 180 rpm and 25 °C for 15 min. Filter out the loaded Y-UiO66-NH2 and determine the concentration of As in the filtrate. Calculate the adsorption rate (E%) (experimental data are shown in Table 2).

[0040] 2. Add the filtered Y-UiO66-NH2 loaded with As(III) to 10 mL of 0.2 mol / L hydrochloric acid solution for desorption. Shake at 180 rpm and 25 °C for 18 min. Filter out Y-UiO66-NH2, determine the As content in the hydrochloric acid desorption solution, and calculate the As desorption rate (S%) (experimental data are shown in Table 2).

[0041] Example 5

[0042] 1. Weigh 0.1 g of Y-UiO66-NH2 as the stationary phase and add it to 1.0 L of 0.50 mg / L aqueous solution with pH 8.0. Shake at 180 rpm and 25 °C for 13 min. Filter out the loaded Y-UiO66-NH2, determine the concentration of P in the filtrate, and calculate the adsorption rate (E%) (experimental data are shown in Table 2).

[0043] 2. Add the filtered P-loaded Y-UiO66-NH2 to 10 mL of 0.2 mol / L hydrochloric acid solution for desorption. Shake at 180 rpm and 25 °C for 18 min. Filter out Y-UiO66-NH2, determine the P content in the hydrochloric acid desorption solution, and calculate the P desorption rate (S%) (experimental data are shown in Table 2).

[0044] Example 6

[0045] 1. Weigh 0.1 g of Y-UiO66-NH2 as the stationary phase and add it to an aqueous solution of 1.0 L of 2.0 mg / L As at pH 8.8. Shake at 180 rpm and 25 °C for 15 min. Filter out the loaded Y-UiO66-NH2, determine the concentration of As in the filtrate, and calculate the adsorption rate (E%) (experimental data are shown in Table 2).

[0046] 2. Add the filtered As-loaded Y-UiO66-NH2 to 10 mL of 0.3 mol / L hydrochloric acid solution for desorption. Shake at 180 rpm and 25 °C for 20 min. Filter out Y-UiO66-NH2, determine the As content in the hydrochloric acid desorption solution, and calculate the As desorption rate (S%) (experimental data are shown in Table 2).

[0047] Example 7

[0048] 1. Weigh 0.1 g of Y-UiO66-NH2 as the stationary phase and add it to 1.0 L of 1.0 mg / L aqueous solution with pH 8.5. Shake at 180 rpm and 25 °C for 15 min. Filter out the loaded Y-UiO66-NH2, determine the concentration of P in the filtrate, and calculate the adsorption rate (E%) (experimental data are shown in Table 2).

[0049] 2. Add the filtered P-loaded Y-UiO66-NH2 to 10 mL of 0.3 mol / L hydrochloric acid solution for desorption. Shake at 180 rpm and 25 °C for 20 min. Filter out Y-UiO66-NH2, determine the P content in the hydrochloric acid desorption solution, and calculate the P desorption rate (S%) (experimental data are shown in Table 2).

[0050] Example 8

[0051] 1. Weigh 0.1 g of Y-UiO66-NH2 as the stationary phase and add it to a 1.0 L mixed aqueous solution containing 2.0 mg / L As and 1.0 mg / L P at pH 8.0. Shake at 180 rpm and 25 °C for 15 min. Filter out the loaded Y-UiO66-NH2 and determine the concentrations of As and P in the filtrate. Calculate the adsorption rates (E%) of As and P respectively (data shown in Table 2).

[0052] 2. Add the filtered Y-UiO66-NH2 loaded with As and P to 10 mL of 0.3 mol / L hydrochloric acid solution for desorption. Shake at 180 rpm and 25 °C for 20 min. Filter out Y-UiO66-NH2 and measure the concentrations of As and P in the hydrochloric acid desorption solution. Calculate the desorption rates (S%) of As and P respectively (experimental data are shown in Table 2).

[0053] Example 9

[0054] 1. Weigh 0.1 g of Y-UiO66-NH2 as the stationary phase and add it to 1.0 L of high-arsenic and phosphorus wastewater containing 1.12 mg / L As and 0.24 mg / L P at pH 7.6. Shake at 180 rpm and 25 °C for 15 min. Filter out the loaded Y-UiO66-NH2 and determine the total concentration of As and P in the filtrate. Calculate the adsorption rates (E%) of As and P respectively (experimental data are shown in Table 2).

[0055] 2. Add the filtered Y-UiO66-NH2 loaded with As and P to 10 mL of 0.3 mol / L hydrochloric acid solution for desorption. Shake at 180 rpm and 25 °C for 20 min. Filter out Y-UiO66-NH2 and measure the concentrations of As and P in the hydrochloric acid desorption solution. Calculate the desorption rates (S%) of As and P respectively (experimental data are shown in Table 2).

[0056] Table 2. Removal of As and / or P from water by Y-UiO66-NH2 adsorbent

[0057]

[0058] from Figure 1 It can be seen that the characteristic diffraction peaks of Zr metal oxide (ZrO2), Y metal oxide (Y2O3), and Y hydroxide (Y(OH)3) did not appear in the XRD pattern of Y-UiO66-NH2, indicating that Zr metal oxide, Y metal oxide, and Y hydroxide were not loaded on the surface of the zirconium-yttrium bimetallic material Y-UiO66-NH2.

[0059] from Figure 2 As can be seen from the isotherm diagram, UiO-66-NH2 is a typical type I isotherm with a specific surface area of ​​1127 m². 2 g -1 It is a typical microporous material, while Y-UiO-66-NH2 approaches the type IV isotherm, and its specific surface area is reduced to 524 m². 2 g -1It is a microporous-mesoporous hybrid material. The nitrogen adsorption-desorption isotherms of UiO66-NH2 and Y-UiO66-NH2 show that with the formation of the zirconium-yttrium bimetallic material Y-UiO-66-NH2, part of the microporous structure of the zirconium-based MOF UiO-66-NH2 is destroyed.

[0060] from Figure 3 (a) It can be observed that in addition to the absorption peaks of C1s, N 1s, O 1s and Zr 3d, the Y-UiO-66-NH2 material also has a Y 3d absorption peak, indicating the formation of the zirconium-yttrium bimetallic material Y-UiO-66-NH2.

Claims

1. A zirconium-yttrium bimetallic MOF adsorbent characterized in that, The adsorbent, designated Y-UiO66-NH2, is prepared by the following method: deprotonated 2-aminoterephthalic acid is added dropwise to a mixed solution containing zirconium oxychloride, yttrium chloride, and glacial acetic acid, using water as a solvent, and stirred at room temperature to obtain the zirconium-yttrium bimetallic MOF adsorbent Y-UiO66-NH2; the molar ratio of zirconium oxychloride, yttrium chloride, glacial acetic acid, 2-aminoterephthalic acid, and sodium hydroxide is 1:1:4:2:

4.

2. A method of making the zirconium-yttrium bimetallic MOF adsorbent of claim 1, characterized in that, Includes the following steps: A certain mass of zirconium oxychloride, yttrium chloride, and glacial acetic acid were added to pure water to obtain a mixed solution. Separately, a certain mass of 2-aminoterephthalic acid was dissolved in an appropriate amount of pure water, and then a certain mass of sodium hydroxide was added to prepare a deprotonated 2-aminoterephthalic acid solution. The prepared deprotonated 2-aminoterephthalic acid solution was added dropwise to the above mixed solution containing zirconium oxychloride, yttrium chloride, and glacial acetic acid. The mixture was stirred at room temperature for more than 10 hours. The resulting solid was washed once with water, then three times with ethanol, and dried in a vacuum drying oven at 60°C for 12 hours to obtain the zirconium-yttrium bimetallic MOF adsorbent Y-UiO66-NH2.

3. The application of a zirconium-yttrium bimetallic MOF adsorbent as described in claim 1 in the removal of arsenic and / or phosphorus from water.

4. The application according to claim 3, characterized in that, The adsorbent is added to a water body containing As and / or P with pH = 6.0 to 8.8 to adsorb As and / or P in the water body.

5. The application according to claim 3, characterized in that, Includes the following steps: (1) Take a certain mass of Y-UiO66-NH2 at a solid-liquid ratio of 1:10 g / L and add it to an aqueous solution with pH = 6.0 to 8.8 and a certain concentration of As and / or P. Shake at 180 rpm and 25℃ for 8 to 15 min, and filter out Y-UiO66-NH2 loaded with As and / or P. (2) Take Y-UiO66-NH2 loaded with As and / or P in step (1), and desorb the As and / or P adsorbed on Y-UiO66-NH2 by constant temperature shaking at 180 rpm and 25℃ for 15 to 20 min with 0.1 to 0.3 mol / L hydrochloric acid aqueous solution at a solid-liquid ratio of 1:0.1 g / L. (3) Take Y-UiO66-NH2 after desorbing As and / or P in step (2), wash it with water twice, repeat steps (1) to (2), and adsorb As and / or P in the same aqueous solution again to realize the reuse of Y-UiO66-NH2.

6. The application according to claim 5, characterized in that: The concentration of the As solution in step (1) is 0.1–2.0 mg / L, and the concentration of P is 0.1–1.0 mg / L.

7. The application according to claim 5, characterized in that: After filtering out Y-UiO66-NH2 loaded with As and / or P in step (1), the concentration of As and / or P in the aqueous phase is further measured. The amount of As and / or P adsorbed by Y-UiO66-NH2 is calculated by the difference method, and the adsorption rate is calculated.

8. The application according to claim 5, characterized in that: After step (2) is completed, the concentrations of As and / or P in the desorption solution are further measured, and the desorption rates of As and / or P are calculated.

9. An application as described in any one of claims 3 to 8, characterized in that: The As in the water is a mixture of As(V) and As(III).

10. An application as described in any one of claims 3 to 8, characterized in that: The P in the water is inorganic P.

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