Defective UiO-66 calcium alginate microspheres capable of specifically adsorbing Norharman in marinating soup and preparation method of UiO-66 calcium alginate microspheres

Abstract

The invention belongs to the technical field of nano materials, and particularly relates to UiO-66 calcium alginate microspheres capable of specifically adsorbing defects of Norharman in marinating soup and a preparation method of the UiO-66 calcium alginate microspheres. The preparation method comprises the following steps: carrying out dielectric barrier discharge (DBD) plasma treatment on UiO-66 to prepare n-UiO-66, and preparing microspheres for specifically adsorbing Norharman by taking calcium alginate as a matrix. No organic solvent or chemical reagent is needed for modification, the cost is low, the operation is simple and convenient, and the method is environment-friendly; by regulating and controlling DBD plasma treatment time, the specific surface area and the pore diameter of n-UiO-66 are increased, and efficient and specific adsorption of Norharman is achieved; the n-UiO-66 has good loading rate, swelling property and regeneration capacity in the calcium alginate. In addition, the n-UiO-66-CAM has biological safety, and has no obvious influence on the color, flavor and the like of the marinated meat products.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials technology, specifically relating to a UiO-66 calcium alginate microsphere that specifically adsorbs Norharman defects in brine and its preparation method. Background Technology

[0002] Braised meat products are favored by consumers for their convenience, unique flavor, and diverse ingredients. This unique flavor is formed through the degradation of meat components (such as free amino acids and fats) and the release of spice components (including phenols, flavonoids, and terpenes) during the braising process. However, prolonged braising can lead to excessive oxidation and degradation of flavor compounds in the meat and spices, resulting in a large amount of heterocyclic aromatic amines (HAAs). Norharman is a significant heterocyclic amine in braising broth, present in high concentrations (41%) and exhibiting high toxicity. It not only possesses certain toxicity (leading to cognitive impairment and depressive behavior) but can also enhance the toxicity of other HAAs. In recent years, methods to reduce the Norharman content in braising broth have mainly included adjusting cooking temperature and pH, reducing the concentration of sugars and amino acids, and adding plant extracts. While these methods can reduce the formation of heterocyclic amines, they also affect the formation of flavor compounds, leading to a decline in product quality.

[0003] Adsorption technology, due to its green, safe, and efficient characteristics, has been widely used in the purification of wastewater and exhaust gases. Commonly used traditional adsorbent materials include activated carbon, zeolite, and silica gel, but they lack adsorption selectivity. Metal-organic frameworks (MOFs), due to their high specific surface area and highly tunable structure, can achieve specific adsorption of target substances. Among them, UiO-66 is a typical MOF material, exhibiting excellent water stability due to its strong Zr-O bonds and the highest coordination number. However, the adsorption capacity of UiO-66 is limited by its inherent microporous structure and the number of active sites, which reduces its adsorption capacity. Specific structural adjustments are needed to achieve high-capacity adsorption.

[0004] To address the aforementioned issues, defect engineering has become an effective means of improving adsorption efficiency and selectivity in recent years. Methods for introducing defect structures into UiO-66 include bottom-up and top-down approaches. Bottom-up methods typically require large amounts of reagents, are costly, inefficient, and cause environmental pollution. Top-down methods generally involve targeted modification of synthesized UiO-66, offering advantages such as high efficiency, environmental friendliness, and suitability for industrial production, and have been widely used in constructing defective UiO-66. However, while traditional chemical modification methods can introduce defects, they require large amounts of reagents, resulting in high costs and significant pollution.

[0005] Therefore, it is urgent to solve the problems of insufficient adsorption selectivity, limited adsorption capacity, complex preparation process, and poor environmental friendliness of existing technologies. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention provides defective UiO-66 calcium alginate microspheres for specific adsorption of Norharman's protein in brine and a method for their preparation. This invention utilizes dielectric barrier discharge (DBD) plasma etching to alter the pore structure of UiO-66 and generates unsaturated sites through chemical bond breaking. Therefore, defective UiO-66 is prepared using DBD plasma technology, and microspheres are fabricated using calcium alginate as a substrate to achieve specific adsorption of Norharman's protein. This method offers advantages such as being green and safe, easy to operate, and suitable for industrial applications.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a method for preparing UiO-66 calcium alginate microspheres that specifically adsorb Norharman defects in brine, comprising the following steps: (1) Synthesis of UiO-66: Zirconium tetrachloride, hydrochloric acid and terephthalic acid were added to N,N'-dimethylformamide in sequence, and the mixture was sonicated until the solution was completely transparent. Then the mixture was heated to react, filtered, washed, centrifuged and dried to obtain UiO-66. (2) Synthesis of n-UiO-66: UiO-66 was subjected to DBD plasma treatment and dried to obtain n-UiO-66; (3) Preparation of n-UiO-66-CAM: n-UiO-66 was dispersed in sodium alginate solution and stirred at room temperature. Then it was dropped into calcium chloride solution to form microspheres. After washing and freeze drying, defective UiO-66 calcium alginate microspheres n-UiO-66-CAM were obtained.

[0008] Further, in step (1), the mass ratio of zirconium tetrachloride to terephthalic acid is 1:1.4-1:1.5.

[0009] Furthermore, in step (1), the mass concentration of the hydrochloric acid is 30-40%.

[0010] Further, in step (1), the temperature of the heating reaction is 200-250 °C, and the heating reaction time is 18-22 h.

[0011] Furthermore, in step (1), the washing refers to washing three times alternately with DMF and methanol at room temperature.

[0012] Furthermore, in step (2), the voltage of the DBD plasma treatment is 50V and the current is 1A.

[0013] Furthermore, in step (2), the DBD plasma treatment time is 10-40 min.

[0014] Further, in step (3), the concentration of the sodium alginate solution is 5-10 g / L, and the mass concentration of the calcium chloride solution is 1-3%.

[0015] Furthermore, in step (3), the washing refers to washing three times with deionized water.

[0016] Further, in step (3), the freeze-drying temperature is -25~-35 ℃, the freeze-drying pressure is 0.5-2 Pa, and the freeze-drying time is 10-14 h.

[0017] A second aspect of the present invention provides a UiO-66 calcium alginate microsphere specifically adsorbing Norharman defects in brine prepared by the above-described preparation method.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a method for preparing calcium alginate microspheres containing UiO-66, which specifically adsorbs Norharman defects in brine. The invention involves treating UiO-66 with DBD plasma to prepare n-UiO-66, and then using calcium alginate as a matrix to prepare microspheres that specifically adsorb Norharman defects. This method eliminates the need for modification with organic solvents or chemical reagents, resulting in low cost, simple operation, and environmental friendliness. By controlling the DBD plasma treatment time, the specific surface area and pore size of n-UiO-66 are increased, achieving highly efficient and specific adsorption of Norharman defects. n-UiO-66 exhibits good loading rate, swelling properties, and regeneration capacity in calcium alginate. Furthermore, n-UiO-66-CAM is biosafety and has no significant impact on the color or flavor of braised meat products. Specifically, the advantages of this invention are as follows: (1) This invention uses DBD plasma to modify UiO-66 without the need for organic solvents or chemical reagents, avoiding the pollution and high cost problems in the traditional chemical modification process. It is simple to operate and environmentally friendly.

[0019] (2) This invention prepares defect-type n-UiO-66 by controlling the processing time of DBD plasma, which significantly increases the specific surface area and pore size, and exposes more unsaturated Zr. 4+ This allows for the efficient and specific adsorption of Norharman molecules at specific sites.

[0020] (3) In this invention, defective n-UiO-66 is loaded into a calcium alginate matrix to form microspheres, which have good loading rate, swelling properties and regeneration ability. In addition, n-UiO-66-CAM has biocompatibility and has no significant impact on the color and flavor of braised meat products. Attached Figure Description

[0021] Figure 1 The images show SEM characterizations of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4. In the images, A, B, and C represent the overall, surface, and cross-sectional morphologies of n-UiO-66-CAM, respectively, and from left to right, they are UiO-66-CAM, 10-UiO-66-CAM, 20-UiO-66-CAM, 30-UiO-66-CAM, and 40-UiO-66-CAM.

[0022] Figure 2 The images show the FT-IR spectra of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4, where A is the FT-IR full wavenumber spectrum; B and C are magnified FT-IR partial views.

[0023] Figure 3 The synthesis mechanism diagram of n-UiO-66-CAM.

[0024] Figure 4 TGA images of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4.

[0025] Figure 5 The image shows a comparison of the Norharman adsorption capacities of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4.

[0026] Figure 6 The adsorption kinetics of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4 are compared.

[0027] Figure 7 The adsorption isotherms of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4 are compared.

[0028] Figure 8 The Norharman adsorption density plot is for n-UiO-66-CAM.

[0029] Figure 9 The graphs show the performance of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4, where A represents the loading rate, solubility, and swelling degree of n-UiO-66-CAM; and B represents the repeatability of n-UiO-66-CAM.

[0030] Figure 10Radar chart for sensory evaluation of braised chicken breast.

[0031] Figure 11 The diagram shows a comparison of the zebrafish behavior of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4. In the diagram, A is the total distance traveled by the zebrafish; B is the average swimming speed of the zebrafish; C is the time spent at rest by the zebrafish; and D is the movement trajectory of the zebrafish exposed to n-UiO-66-CAM. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0034] Example 1: Preparation of 10-UiO-66-CAM (1) Synthesis of UiO-66: Zirconium tetrachloride (1.16 g), 35% hydrochloric acid (0.88 mL), and terephthalic acid (1.66 g) were added sequentially to a conical flask containing 30 mL of N,N'-dimethylformamide. The mixture was ultrasonically treated in an ultrasonic cleaner (AK-100SD) until the solution was completely transparent, and then transferred to a polytetrafluoroethylene-lined reactor (BE100-C276) and heated to 220 °C for 20 h. The white solid was collected by filtration and then washed three times alternately with DMF (30 mL) and methanol (30 mL) at room temperature. Finally, the precipitate was collected by centrifugation at 4000 rpm / min for 10 min and dried overnight in an oven at 60 °C.

[0035] (2) Synthesis of 10-UiO-66: UiO-66 was treated using a DBD plasma apparatus (Nanjing Suman Electronics Co., Ltd., China), which consisted of a reaction chamber (DBD-50) and a voltage regulator (CTP-2000 KP). 3 g of UiO-66 was evenly spread on a quartz medium, gently tapped to smooth the surface, and then placed in the reaction chamber. The sample was treated with DBD plasma at 50 V and 1 A for 10 min (10-UiO-66), then dried in a hot air oven (DHG101-1A) at 60 °C for 12 h, and finally collected and placed in a brown bottle.

[0036] (3) Preparation of 10-UiO-66-CAM: 10-UiO-66 (250 mg) was dispersed in sodium alginate solution (5 mL, 8 g / L) and magnetically stirred at 500 rpm / min for 10 min at room temperature. Subsequently, 1 mL of the mixture was pipetted into calcium chloride solution (100 mL, 2%) to form microspheres. The microspheres were washed three times with deionized water and then freeze-dried at -30 °C and 1 Pa for 12 h. Based on the DBD plasma treatment time of n-UiO-66, the microspheres were labeled as 10-UiO-66-CAM.

[0037] Example 2: Preparation of 20-UiO-66-CAM (1) Synthesis of UiO-66: Zirconium tetrachloride (1.16 g), 35% hydrochloric acid (0.88 mL), and terephthalic acid (1.66 g) were added sequentially to a conical flask containing 30 mL of N,N'-dimethylformamide. The mixture was ultrasonically treated in an ultrasonic cleaner (AK-100SD) until the solution was completely transparent, and then transferred to a polytetrafluoroethylene-lined reactor (BE100-C276) and heated to 220 °C for 20 h. The white solid was collected by filtration and then washed three times alternately with DMF (30 mL) and methanol (30 mL) at room temperature. Finally, the precipitate was collected by centrifugation at 4000 rpm / min for 10 min and dried overnight in an oven at 60 °C.

[0038] (2) Synthesis of 20-UiO-66: UiO-66 was treated using a DBD plasma apparatus (Nanjing Suman Electronics Co., Ltd., China), which consisted of a reaction chamber (DBD-50) and a voltage regulator (CTP-2000 KP). 3 g of UiO-66 was evenly spread on a quartz medium, gently tapped to smooth the surface, and then placed in the reaction chamber. The sample was treated with DBD plasma at 50 V and 1 A for 20 min (20-UiO-66), then dried in a hot air oven (DHG101-1A) at 60 °C for 12 h, and finally collected and placed in a brown bottle.

[0039] (3) Preparation of 20-UiO-66-CAM: 20-UiO-66 (250 mg) was dispersed in sodium alginate solution (5 mL, 8 g / L) and magnetically stirred at 500 rpm / min for 10 min at room temperature. Subsequently, 1 mL of the mixture was pipetted into calcium chloride solution (100 mL, 2%) to form microspheres. The microspheres were washed three times with deionized water and then freeze-dried at -30 °C and 1 Pa for 12 h. Based on the DBD plasma treatment time of n-UiO-66, the microspheres were labeled as 20-UiO-66-CAM.

[0040] Example 3: Preparation of 30-UiO-66-CAM (1) Synthesis of UiO-66: Zirconium tetrachloride (1.16 g), 35% hydrochloric acid (0.88 mL), and terephthalic acid (1.66 g) were added sequentially to a conical flask containing 30 mL of N,N'-dimethylformamide. The mixture was ultrasonically treated in an ultrasonic cleaner (AK-100SD) until the solution was completely transparent, and then transferred to a polytetrafluoroethylene-lined reactor (BE100-C276) and heated to 220 °C for 20 h. The white solid was collected by filtration and then washed three times alternately with DMF (30 mL) and methanol (30 mL) at room temperature. Finally, the precipitate was collected by centrifugation at 4000 rpm / min for 10 min and dried overnight in an oven at 60 °C.

[0041] (2) Synthesis of 30-UiO-66: UiO-66 was treated using a DBD plasma device (Nanjing Suman Electronics Co., Ltd., China), which consisted of a reaction chamber (DBD-50) and a voltage regulator (CTP-2000 KP). 3 g of UiO-66 was evenly spread on a quartz medium, gently tapped to smooth the surface, and then placed in the reaction chamber. The sample was treated with DBD plasma at 50 V and 1 A for 30 min (30-UiO-66), then dried in a hot air oven (DHG101-1A) at 60 °C for 12 h, and finally collected and placed in a brown bottle.

[0042] (3) Preparation of 30-UiO-66-CAM: 250 mg of 30-UiO-66 was dispersed in sodium alginate solution (5 mL, 8 g / L) and magnetically stirred at 500 rpm / min for 10 min at room temperature. Subsequently, 1 mL of the mixture was pipetted into 100 mL of calcium chloride solution (2%) to form microspheres. The microspheres were washed three times with deionized water and then freeze-dried at -30 °C and 1 Pa for 12 h. Based on the DBD plasma treatment time of n-UiO-66, the microspheres were labeled as 30-UiO-66-CAM.

[0043] Example 4: Preparation of 40-UiO-66-CAM (1) Synthesis of UiO-66: Zirconium tetrachloride (1.16 g), 35% hydrochloric acid (0.88 mL), and terephthalic acid (1.66 g) were added sequentially to a conical flask containing 30 mL of N,N'-dimethylformamide. The mixture was ultrasonically treated in an ultrasonic cleaner (AK-100SD) until the solution was completely transparent, and then transferred to a polytetrafluoroethylene-lined reactor (BE100-C276) and heated to 220 °C for 20 h. The white solid was collected by filtration and then washed three times alternately with DMF (30 mL) and methanol (30 mL) at room temperature. Finally, the precipitate was collected by centrifugation at 4000 rpm / min for 10 min and dried overnight in an oven at 60 °C.

[0044] (2) Synthesis of 40-UiO-66: UiO-66 was treated using a DBD plasma device (Nanjing Suman Electronics Co., Ltd., China), which consisted of a reaction chamber (DBD-50) and a voltage regulator (CTP-2000 KP). 3 g of UiO-66 was evenly spread on a quartz medium, gently tapped to smooth the surface, and then placed in the reaction chamber. The sample was treated with DBD plasma at 50 V and 1 A for 40 min (40-UiO-66), then dried in a hot air oven (DHG101-1A) at 60 °C for 12 h, and finally collected and placed in a brown bottle.

[0045] (3) Preparation of 40-UiO-66-CAM: 40-UiO-66 (250 mg) was dispersed in sodium alginate solution (5 mL, 8 g / L) and magnetically stirred at 500 rpm / min for 10 min at room temperature. Subsequently, 1 mL of the mixture was pipetted into calcium chloride solution (100 mL, 2%) to form microspheres. The microspheres were washed three times with deionized water and then freeze-dried at -30 °C and 1 Pa for 12 h. Based on the DBD plasma treatment time of n-UiO-66, the microspheres were labeled as 40-UiO-66-CAM.

[0046] Comparative Example 1: Preparation of UiO-66-CAM (1) Synthesis of UiO-66: Zirconium tetrachloride (1.16 g), 35% hydrochloric acid (0.88 mL), and terephthalic acid (1.66 g) were added sequentially to a conical flask containing 30 mL of N,N'-dimethylformamide. The mixture was ultrasonically treated in an ultrasonic cleaner (AK-100SD) until the solution was completely transparent, and then transferred to a polytetrafluoroethylene-lined reactor (BE100-C276) and heated to 220 °C for 20 h. The white solid was collected by filtration and then washed three times alternately with DMF (30 mL) and methanol (30 mL) at room temperature. Finally, the precipitate was collected by centrifugation at 4000 rpm / min for 10 min and dried overnight in an oven at 60 °C.

[0047] (2) Preparation of UiO-66-CAM: UiO-66 (250 mg) was dispersed in sodium alginate solution (5 mL, 8 g / L) and magnetically stirred at 500 rpm / min for 10 min at room temperature. Subsequently, 1 mL of the mixture was pipetted into calcium chloride solution (100 mL, 2%) to form microspheres. The microspheres were washed three times with deionized water and then freeze-dried at -30 ℃ and 1 Pa for 12 h to obtain UiO-66-CAM.

[0048] Test Example 1: Microstructure Analysis The morphology of n-UiO-66-CAM in Examples 1-4 and Comparative Example 1 was characterized using SEM, such as... Figure 1 As shown, with the DBD plasma treatment time extended to 20 min, the morphology of n-UiO-66-CAM became increasingly uniform and regular. This is because the DBD plasma enhanced the dispersibility of n-UiO-66, thus facilitating the formation of a uniformly mixed suspension with sodium alginate, followed by Ca... 2+Cross-linking forms regular microspheres. Furthermore, n-UiO-66 is uniformly distributed within the calcium alginate matrix, exhibiting large pores. However, when the treatment time exceeds 20 min, noticeable cracks appear on the surface of n-UiO-66-CAM, and the distribution of n-UiO-66 within the matrix becomes uneven. This is attributed to the excessive aggregation and breakage of n-UiO-66 due to prolonged treatment, resulting in a deterioration in its interaction with the calcium alginate matrix.

[0049] Test Example 2: Determination of Fourier Transform Infrared Spectroscopy The functional groups of n-UiO-66-CAM in Examples 1-4 and Comparative Example 1 were analyzed by FT-IR spectroscopy. Figure 2 As shown, this spectrum is in high agreement with that of n-UiO-66, and no new peaks were observed, indicating that the addition of sodium alginate (SA) did not induce the formation of new chemical bonds. Furthermore, local magnification of the spectrum revealed that with increasing DBD plasma treatment time, both asymmetric and symmetric CO stretching vibration peaks (1580 and 1394 cm⁻¹) appeared. -1 The position remains unchanged, indicating that the COO⁻ group of calcium alginate will not react with Zr. 4+ Coordination bonds are formed. This further confirms that the interaction between n-UiO-66 and calcium alginate is achieved through physical encapsulation, as shown in the synthesis mechanism diagram below. Figure 3 As shown.

[0050] Test Example 3: Thermogravimetric Analysis The thermal stability of n-UiO-66-CAM in Examples 1-4 and Comparative Example 1 was analyzed by TGA. According to the FT-IR results, the binding mechanism of n-UiO-66 to calcium alginate is physical encapsulation, indicating that the thermal degradation of n-UiO-66-CAM is mainly caused by structural changes in n-UiO-66. Figure 4 As shown, there are three distinct weight loss stages. Weight loss below 150 °C is attributed to the removal of physically adsorbed water, while the increased weight loss rate after DBD treatment is related to the enhanced hydrophilicity resulting from the introduction of oxygen-containing groups. In the range of 150 °C to 450 °C, the calcium alginate matrix and organic ligands decompose. Prolonged DBD plasma treatment leads to decreased thermal stability in this stage, as ligand defects in n-UiO-66 accelerate the decomposition of the framework and calcium alginate matrix. Finally, decomposition above 500 °C involves the collapse of residual organic matter and the metallic framework. The residual mass trend of n-UiO-66-CAM in this stage is similar to that of n-UiO-66.

[0051] Test Example 4: Norharman Adsorption Experiment The Norharman adsorption of n-UiO-66-CAM in Examples 1-4 and Comparative Example 1 was tested, and the results were as follows: Figure 5 As shown, 20-UiO-66-CAM exhibited the highest adsorption capacity, approximately 136.4 mg / g, which can be attributed to the largest specific surface area and abundant exposed Zr in 20-UiO-66. 4+ Site selection and optimized hierarchical pore structure. The BET specific surface area, pore volume, and pore size of n-UiO-66 are shown in Table 1. The specific surface area of ​​n-UiO-66 increased from 827.08 m² to 1182.29 m². 2 / g. 20-UiO-66 has the highest V mes / V t (49%), and the average pore size increased from 1.40 nm to 3.04 nm. These results indicate that DBD plasma treatment introduces ligand defects, promoting the transformation from micropores to mesopores. Furthermore, DBD plasma treatment enhances the dispersibility of 20-UiO-66, resulting in a uniformly distributed and tightly bound network structure within the microspheres, allowing Norharman to easily penetrate the calcium alginate matrix and effectively reach the active sites of n-UiO-66. However, when the treatment time exceeds 20 min, the adsorption capacity decreases because overtreatment leads to the collapse and carbonization of the n-UiO-66 structure, causing particle aggregation and hindering Norharman from entering the n-UiO-66-CAM.

[0052] Table 1 sample <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Total pore volume (cm 3 / g)]]> <![CDATA[Micropore volume (cm 3 / g)]]> Aperture (nm) Mesopority UiO-66 827.08 0.31 0.27 1.40 0.12 10-UiO-66 923.26 0.36 0.24 2.82 0.33 20-UiO-66 1182.29 0.43 0.22 3.04 0.49 30-UiO-66 901.66 0.33 0.18 2.86 0.45 40-UiO-66 604.09 0.30 0.18 2.56 0.40 Test Example 5: Adsorption Kinetics Test The adsorption process of Norharman on n-UiO-66-CAM in Examples 1-4 and Comparative Example 1 was analyzed using pseudo-first-order and pseudo-second-order kinetic models. The fitted curves are shown below. Figure 6 As shown. This adsorption process is more consistent with the pseudo-second-order model (R0). 2 >0.97), indicating that chemisorption is the main mechanism, which is related to the ligand defects generated by DBD plasma treatment and the exposure of unsaturated Zr. 4+ The consistent site locations suggest that the N atom in the Norharman molecule is likely associated with these Zr atoms. 4+ Strong interactions occur at the adsorption sites. However, when the treatment time exceeds 20 min, the collapse of micropores reduces the number of available adsorption sites, and the aggregation of n-UiO-66 slows down the Norharman diffusion rate. Furthermore, the correlation coefficient of the pseudo-first-order model is 0.90, indicating that physisorption also makes a significant contribution to the overall adsorption process.

[0053] Test Example 6: Adsorption Isotherm Test like Figure 7 As shown, the effect of initial Norharman concentration on adsorption was investigated using Langmuir and Freundlich models. With increasing initial concentration, the adsorption capacity of n-UiO-66-CAM increased significantly. The adsorption data showed excellent agreement with the Langmuir model (R0). 2 > 0.99), indicating that the adsorption of Norharman on n-UiO-66-CAM mainly follows monolayer adsorption characteristics. This can be attributed to the fact that DBD plasma treatment not only increases the coordination-unsaturated Zr 4+ The number of adsorption sites also ensures a high degree of uniformity in adsorption energy at these sites, resulting in a uniform and highly active surface. Furthermore, 20-UiO-66-CAM exhibits the maximum adsorption capacity predicted by Langmuir, achieving an adsorption capacity of 112.64 mg / g for Norharman adsorption.

[0054] Test Example 7: Adsorption Mechanism like Figure 8 As shown, the adsorption density plot of Norharman reveals the ligand defect sites of Norharman at n-UiO-66 (especially near the exposed unsaturated Zr). 4+ Preferential adsorption at (sites). The change in adsorption density gradient within the defect region indicates strong electronic interactions during adsorption, further confirming that Norharman's adsorption on n-UiO-66 involves both physical and chemical interactions.

[0055] The adsorption energies of n-UiO-66 for typical heterocyclic amines (HAAs) in five different brines were calculated using density functional theory. The molecular sizes and adsorption energies of the HAAs in the brines are shown in Table 2. The order of adsorption energies is: Norharman (-20.21 kcal / mol) < Harman (-15.37 kcal / mol) < IQ (-12.58 kcal / mol) < MeIQx (-10.15 kcal / mol) < PhIP (-6.42 kcal / mol), indicating that the interaction between Norharman and n-UiO-66 is the strongest. Furthermore, the average radii of these five heterocyclic amines are 2.46 Å (Norharman), 3.46 Å (Harman), 4.03 Å (IQ), 3.71 Å (MeIQx), and 3.57 Å (PhIP), respectively. This indicates that the micropores of n-UiO-66 significantly hinder the entry of larger molecules (IQ, MeIQx, PhIP), while the -CH3 group in Harman restricts the pyridine nitrogen atom from approaching Zr. 4+ Site.

[0056] Table 2 HAAs Three-dimensional dimensions(nm) Average radius (Å) Adsorption energy (kcal / mol) Norharman 1.06 × 0.74 × 0.32 2.46 -20.21 Harman 1.05 × 0.79 × 0.40 3.46 -15.37 PhIP 1.37 × 0.76 × 0.50 4.03 -6.42 MeIQx 1.18 × 0.86 × 0.40 3.71 -10.15 IQ 1.15 × 0.78 × 0.40 3.57 -12.58 Comprehensive characterization and adsorption experiments indicate that the adsorption of Norharman on n-UiO-66 is a multi-mechanism synergistic process, primarily controlled by chemocoordination. Ligand defects generated by DBD plasma treatment expose abundant Lewis acidic Zr. 4+ These sites form strong Zr-N coordination bonds with the Lewis basic nitrogen atoms in Norharman. Furthermore, π-π stacking and hydrogen bonding interactions also occur between n-UiO-66 and Norharman.

[0057] Test Example 8: Performance Measurement The loading rate, solubility, and swelling degree of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4 are as follows: Figure 9 As shown in Figure A, the loading rate of n-UiO-66-CAM increased with increasing DBD treatment time, peaking at approximately 20 min. This is because DBD treatment improved the dispersibility of n-UiO-66, allowing more n-UiO-66 to be uniformly loaded into the calcium alginate network. Treatment exceeding 20 min led to carbonization and severe aggregation of n-UiO-66, resulting in poor compatibility with the calcium alginate matrix. The solubility of all n-UiO-66-CAMs was relatively low, indicating that n-UiO-66-CAM is insoluble in water. This is because calcium alginate is a three-dimensional covalent network linked by multiple sites and high-strength ionic bonds. Furthermore, the solubility of n-UiO-66-CAM did not differ significantly because the n-UiO-66 treated by DBD plasma only physically encapsulated it as a filler and did not disrupt the cross-linked structure of n-UiO-66-CAM. The swelling degree of n-UiO-66-CAM first increased and then decreased with the extension of treatment time. This is because DBD plasma enhances the hydrophilicity of n-UiO-66, thereby attracting more water molecules into the interior of the microspheres. However, when the treatment time exceeds 20 min, n-UiO-66 undergoes severe aggregation, accompanied by surface carbonization and enhanced hydrophobicity.

[0058] To determine the reproducibility of n-UiO-66-CAM, it was regenerated with ethanol and subjected to five Norharman adsorption cycles at 25 °C. The reproducibility test results are as follows: Figure 9 As shown in B, 20-UiO-66-CAM had the highest initial adsorption rate (125 mg / g) and the least cyclic decay, maintaining an adsorption rate of approximately 115 mg / g after five adsorption-regeneration cycles.

[0059] Test Example 9: Sensory Evaluation Figure 10Sensory evaluation radar charts for two groups of braised chicken breast samples (control group (braised chicken breast samples without 20-UiO-66-CAM) and 20-UiO-66-CAM group) are presented. Although the shapes of the sensory evaluation radar charts differ between the two groups, there is no significant difference in overall sensory characteristics. This indicates that 20-UiO-66-CAM did not undergo structural decomposition due to heat and oil contact during Norharman adsorption, nor did it release any unpleasant odors. Simultaneously, this also confirms that n-UiO-66-CAM successfully and selectively adsorbed Norharman without significantly adsorbing flavor compounds (such as aldehydes, ketones, esters, etc.).

[0060] Test Example 10: Zebrafish Behavioral Analysis The biosafety of n-UiO-66-CAM prepared in Comparative Example 1 and Examples 1-4 was analyzed using zebrafish behavioral studies. The total distance traveled, swimming speed, and resting time of zebrafish exposed to n-UiO-66-CAM were assessed. Figure 11 As shown in A, B, and C. The results indicate that there was no significant difference in the mobility of zebrafish exposed to n-UiO-66-CAM for different treatment times. Furthermore, as shown in Figures A, B, and C. Figure 11 As shown in Figure D, the swimming tracks of zebrafish were distributed throughout the open area, mainly concentrated at the edge of the open area, with no significant difference in swimming paths. This indicates that n-UiO-66-CAM has minimal impact on the swimming tracks of zebrafish. These results confirm the biocompatibility of n-UiO-66-CAM.

[0061] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for preparing a defective UiO-66 calcium alginate microsphere that specifically adsorbs Norharman in halogen soup, characterized by, The method comprises the following steps: (1) Synthesis of UiO-66: zirconium tetrachloride, hydrochloric acid and terephthalic acid are sequentially added into N,N'-dimethylformamide, ultrasonic treatment is performed until the solution is completely transparent, then heating reaction is performed, filtration, washing, centrifugation, drying, and UiO-66 is obtained; (2) Synthesis of n-UiO-66: DBD plasma treatment is performed on the UiO-66, and drying is performed to obtain n-UiO-66; (3) Preparation of n-UiO-66-CAM: n-UiO-66 is dispersed in a sodium alginate solution, stirring is performed at room temperature, then a calcium chloride solution is added dropwise to form microspheres, washing, freeze-drying, and the defective UiO-66 calcium alginate microspheres n-UiO-66-CAM are obtained.

2. The method of claim 1, wherein the method of preparing a specific adsorption of Norharman in halogen soup defect UiO-66 calcium alginate microspheres is characterized by, In step (1), the mass ratio of the zirconium tetrachloride and the terephthalic acid is 1:1.4-1:1.

5.

3. The method of claim 1, wherein the method of preparing a specific adsorption of Norharman in halogen soup defect UiO-66 calcium alginate microspheres is characterized by, In step (1), the mass concentration of the hydrochloric acid is 30-40%.

4. The method of claim 1, wherein the method of preparing a specific adsorption of Norharman in halogen soup defect UiO-66 calcium alginate microspheres is characterized by, In step (1), the temperature of the heating reaction is 200-250 ℃, and the time of the heating reaction is 18-22 h.

5. The method of claim 1, wherein the method of preparing a specific adsorption of Norharman in halogen soup defect UiO-66 calcium alginate microspheres is characterized by, In step (1), the washing refers to that the washing is alternately performed with DMF and methanol for three times at room temperature.

6. The method of claim 1, wherein the method of preparing a specific adsorption of Norharman in halogen soup defect UiO-66 calcium alginate microspheres is characterized by, In step (2), the voltage of the DBD plasma treatment is 50 V, and the current is 1 A.

7. The method of claim 1, wherein the method of preparing a specific adsorption of Norharman in halogen soup defect UiO-66 calcium alginate microspheres is characterized by, In step (2), the time of the DBD plasma treatment is 10-40 min.

8. The method of claim 1, wherein the method of preparing a specific adsorption of Norharman in halogen soup defect UiO-66 calcium alginate microspheres is characterized by, In step (3), the concentration of the sodium alginate solution is 5-10 g / L, and the mass concentration of the calcium chloride solution is 1-3%.

9. The method of claim 1, wherein the method of preparing a specific adsorption of Norharman in halogen soup defect UiO-66 calcium alginate microspheres is characterized by, In step (3), the temperature of the freeze-drying is -25~-35 ℃, the pressure of the freeze-drying is 0.5-2 Pa, and the time of the freeze-drying is 10-14 h.

10. Defective UiO-66 calcium alginate microspheres for specifically adsorbing Norharman in halogen soup, which are prepared by the preparation method in any one of claims 1-9.

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