Sulfhydryl resin as well as preparation method and application thereof

Abstract

The invention discloses sulfydryl resin as well as a preparation method and application thereof, and belongs to the technical field of polymer synthesis. The sulfydryl resin is brand-new sulfydryl polyester resin, Ti is introduced into organic silicon resin structurally, and a large number of sulfydryl propyl groups which are not connected to a main chain are utilized, so that the sulfydryl resin has excellent heavy metal adsorption performance. No additional organic solvent is needed in the synthesis process, the reaction byproduct is high-purity methanol or ethanol, and the method has great economical efficiency and is green, efficient and environmentally friendly. The sulfydryl resin has the characteristics of good stability, convenience in use, safety, no toxicity and the like, and has a remarkable removal effect on heavy metals in a water body.

Description

Technical Field

[0001] This application relates to a mercapto resin, its preparation method, and its application, belonging to the field of polymer synthesis technology. Background Technology

[0002] With the development of modern industry, heavy metal water pollution has become one of the most important environmental problems. Heavy metal ions are highly toxic and difficult to degrade, posing a significant threat to humans, aquatic animals, and plants, and damaging ecosystems. Adsorption methods, with their advantages of low cost, high removal efficiency, and recyclability, have become an important method for wastewater treatment. Currently, the environmental protection water treatment industry widely uses chelating resins to remove heavy metal ions from water bodies.

[0003] Chelating resins offer advantages such as high efficiency, wide adaptability, ease of operation, and environmental safety in treating heavy metals. However, they also have drawbacks, including high investment costs, difficult maintenance and management, poor treatment effect on high-concentration heavy metal wastewater, and sensitivity to organic matter in water. Therefore, developing novel, highly efficient, stable, and inexpensive resins for removing heavy metals holds significant application potential.

[0004] Organosilicon polymer composites are a class of materials containing organic-inorganic hybrid structures, characterized by hydrophobicity, thermal stability, and ease of modification, offering a novel solution for heavy metal treatment. Introducing chelating groups into organosilicon polymers, rather than modifying them, can significantly improve the polymer's ability to remove heavy metal ions, enhance stability, and, most importantly, reduce the cost of chelating resins. However, organosilicon polymers also have some drawbacks, such as the high polarity of the O-Si-O bonds, which are easily broken under electrophilic or nucleophilic attack; and the low mechanical strength and poor adhesion of pure organosilicon resins. Summary of the Invention

[0005] To address the challenge of balancing high-efficiency adsorption with cost-effectiveness, environmental friendliness, and stability in resin materials for removing heavy metal ions from water, this application provides a thiol resin, its preparation method, and its applications. Introducing Ti into the organosilicon resin improves its low mechanical strength and poor adhesion. Furthermore, utilizing the abundant unattached mercaptopropyl groups on the main chain, the thiol resin exhibits excellent heavy metal adsorption performance.

[0006] The technical solution adopted in this application is as follows:

[0007] According to a first aspect of this application, a thiol resin is provided, wherein the chemical formula of the thiol resin includes structural units as shown in Formula I:

[0008]

[0009] Where n = 0 to 3, m = 1 to 20, and R1 is H or cyano.

[0010] Optionally, the degree of polymerization of the structural units in the thiol resin is 12 to 20.

[0011] Optionally, m = 4 in Equations I and II.

[0012] Optionally, the activated mercapto resin achieves a removal rate of over 95% for mercury ions at a concentration of approximately 1 ppm.

[0013] Optionally, formula I is selected from one of the structures shown in formula Ia, formula Ib, and formula Ic:

[0014]

[0015]

[0016] Where m = 1 to 20, and R1 is H or cyano.

[0017] According to a second aspect of this application, a method for preparing a thiol resin is provided, comprising the following steps:

[0018] The thiol resin is prepared by transesterification of a mixture containing titanate, polyol and thiol silicate.

[0019] Optionally, the molar ratio of the titanate to the polyol and mercaptosilicate is 1:(30-600):(20-200).

[0020] Optionally, the molar ratio of the titanate to the polyol is selected from any value among 1:30, 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, and 1:600, or any range between the two.

[0021] Optionally, the molar ratio of the titanate to the mercaptosilicate is selected from any value among 1:20, 1:50, 1:100, 1:150, and 1:200, or any range between the two.

[0022] Optionally, the polyol contains at least two hydroxyl groups.

[0023] Optionally, the polyol is selected from at least one of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000, polyethylene glycol 6000, polyethylene glycol 8000, polyethylene glycol 10000, 1,4-cyclohexanediol, 1,4-cyclohexanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, terephthalic acid, glycerol, trimethylolpropane, pentaerythritol, xylitol, and sorbitol.

[0024] Optionally, the titanate is selected from at least one of compounds having the chemical formula shown in Formula II:

[0025]

[0026] R2, R3, R4, and R5 are independently selected from C1 to C8 alkyl groups.

[0027] Optionally, the titanate includes at least one of tetraethyl titanate, tetrabutyl titanate, tetraisopropyl titanate, tetrahexyl titanate, and tetraisooctyl titanate.

[0028] In this application, the introduction of Ti serves as a promoter for the transesterification reaction; without titanium, the ester cannot undergo polymerization.

[0029] Optionally, the mixture may also include silicates;

[0030] The silicate ester is from at least one of compounds having the structure shown in Formula III:

[0031]

[0032] R6, R7, R8, and R9 are independently selected from C1 to C4 alkyl groups.

[0033] The purpose of adding both silicate and mercaptosilicate is to increase the degree of polymerization of the polymer.

[0034] Optionally, the silicate ester is selected from at least one of methyl silicate, tetraethyl silicate, tetrapropyl silicate, and tetrabutyl silicate.

[0035] Optionally, the molar ratio of the titanate to the polyol, mercaptosilicate, and silicate is 1:(30-600):(20-200):(0-200), wherein the proportion of silicate is not 0.

[0036] Optionally, the molar ratio of the titanate to the polyol is selected from any value among 1:30, 1:50, 1:100, 1:200, 1:300, 1:400, 1:500, and 1:600, or any range between the two.

[0037] Optionally, the molar ratio of the titanate to the mercaptosilicate is selected from any value among 1:20, 1:50, 1:100, 1:150, and 1:200, or any range between the two.

[0038] Optionally, the molar ratio of the titanate to the silicate is selected from any value among 1:0.1, 1:1, 1:5, 1:10, 1:20, 1:50, 1:100, 1:150, and 1:200, or any range between the two.

[0039] Optionally, the thiosilicate is selected from at least one of compounds having the chemical formula shown in Formula IV:

[0040]

[0041] Among them, R 10 R 11 R 13 Independently selected from one of methyl, methoxy, and ethoxy, R 12 Select one of the structures shown in formula V:

[0042] Where n = 0 to 3, and R1 is H or cyano.

[0043] Optional, R 12 It is selected from one of mercaptoethyl, mercaptopropylthiocyanopropyl, and ethylthio.

[0044] Optionally, the mercaptosilicone ester is selected from at least one of (ethylthio)trimethylsilane, 3-thiocyanopropyltrimethoxysilane, 3-cyanopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and 2-mercaptoethyltriethoxysilane.

[0045] Optionally, the transesterification conditions include: the reaction process is carried out in an inactive atmosphere, the reaction temperature is 80-180°C, and the reaction time is 2-20 h.

[0046] Optionally, the inactive atmosphere includes at least one of nitrogen and an inert gas.

[0047] Optionally, the conversion rate of the transesterification reaction is 60% to 80%.

[0048] Optionally, the reaction temperature in the transesterification reaction is selected from any value or a range between 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, and 180℃.

[0049] Optionally, the reaction time in the transesterification reaction conditions is selected from any value or a range between 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, and 20h.

[0050] Optionally, the reaction time in the transesterification reaction is 6 to 16 hours.

[0051] Optionally, the preparation method further includes: performing vacuum distillation after the reaction.

[0052] Optionally, the conditions for vacuum distillation include: a vacuum degree of 0.01–5 kPa, a vacuum distillation temperature of 170–230 °C, and a vacuum distillation time of 0.5–5 h.

[0053] Optionally, the vacuum degree in the vacuum distillation conditions is selected from any value or a range between 0.01 kPa, 0.02 kPa, 0.05 kPa, 0.05 kPa, 0.1 kPa, 0.5 kPa, 1 kPa, 2 kPa, 3 kPa, 4 kPa, and 5 kPa.

[0054] Optionally, the vacuum degree in the vacuum distillation is 1 to 5 kPa.

[0055] Optionally, the vacuum distillation temperature is selected from any value or a range between 170℃, 180℃, 190℃, 200℃, 210℃, 180℃, 190℃, 200℃, 210℃, 220℃, and 230℃.

[0056] Optionally, the time for vacuum distillation in the vacuum distillation conditions is selected from any value of 0.5h, 1h, 2h, 3h, 4h, 5h, or any range between two.

[0057] Optionally, both the reaction and vacuum distillation steps are transesterification processes, and the conversion rate after the reaction and vacuum distillation processes is greater than 90%.

[0058] Optional steps include the following:

[0059] The mercapto resin is prepared by transesterification of a mixture containing polyol, titanate, and mercaptosilicate, followed by vacuum distillation of the reaction product.

[0060] Optional steps include the following:

[0061] A mixture containing polyol, titanate, and mercaptosilicate is subjected to transesterification under stirring, protected by an inactive atmosphere. The reaction temperature is between 80 and 180°C, and the reaction time is between 2 and 20 h. The reaction product is then subjected to vacuum distillation, with the system vacuum degree controlled at 0.01 to 5 kPa, the reaction temperature between 170 and 230°C, and the reaction time between 0.5 and 5 h, to obtain the mercapto resin.

[0062] According to a third aspect of this application, the above-described thiol resin or the thiol resin prepared according to any one of the above-described preparation methods is provided as an application of heavy metal adsorbent in wastewater treatment.

[0063] In this application, "C1~C8, C1~C4" etc. all refer to the number of carbon atoms contained in the group.

[0064] In this application, "alkyl" refers to a group formed by the loss of any one hydrogen atom from an alkane molecule.

[0065] The beneficial effects that this application can produce include:

[0066] (1) The mercapto resin synthesized in this application has a good adsorption effect on heavy metal ions, especially mercury ions, and can effectively remove mercury ions from water bodies for use in the environmental protection field.

[0067] (2) The synthesis of the mercapto resin in this application does not require additional organic solvents, and the reaction byproducts are high-purity methanol or ethanol. It is economical, green, efficient and environmentally friendly, safe and non-toxic, and has good biological safety.

[0068] (3) The novel thiol resin synthesized in this application not only has improved stability compared with traditional resins, but also has excellent adsorption performance. It has the advantages of being functional and low cost, has good by-products and is highly economical, and is easier to promote industrially. Attached Figure Description

[0069] Figure 1 The thermogravimetric spectrum of mercapto resin in sample #5 of this application is shown.

[0070] Figure 2 This study compares the adsorption performance of mercapto resins for different heavy metal ions in samples 5# and 11# of this application. Detailed Implementation

[0071] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0072] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0073] Unless otherwise specified, all test methods are conventional and all instrument settings are those recommended by the manufacturer.

[0074] The analysis method in the embodiments of this application is as follows:

[0075] Thermogravimetric analysis was performed using a TAQ-600 thermogravimetric analyzer manufactured by TA Instruments.

[0076] The concentration of mercury ions in the solution was determined using an atomic fluorescence spectrophotometer, model HGF-V2, manufactured by Haiguang Instruments Co., Ltd.

[0077] The conversion rate of the transesterification reaction in the embodiments of this application is calculated as follows:

[0078] Based on the number n of the alcohols distilled off during the reaction, the number of groups participating in the transesterification reaction is determined to be n, and the total number of moles of titanate and silicate in the reaction raw materials is m. Then the conversion rate of the transesterification reaction is n:4m.

[0079] Example 1

[0080] 20.85 g of PEG-400, 6.52 g of γ-mercaptopropyltrimethoxysilane, and 0.45 g of tetraethyl titanate were added to a three-necked flask. A distillation apparatus was connected, and the mixture was heated to 175 °C under nitrogen protection with stirring, and reacted for 16 hours. During this process, a large amount of methanol was distilled off, and the conversion rate of the transesterification reaction was 75%. Then, a vacuum distillation apparatus was connected, and the reaction was carried out under reduced pressure, controlling the vacuum level at 1 kPa. The temperature was raised to 200 °C, and after one hour of reaction, the reaction was stopped. After naturally cooling to room temperature, the sample was removed and labeled #1. The conversion rate of the transesterification reaction was 93%.

[0081] Example 2

[0082] The preparation method is the same as in Example 1, except that the temperature is raised to 180°C under nitrogen protection and the reaction is carried out for 2 hours. The prepared sample is marked as 2#.

[0083] Example 3

[0084] The preparation method is the same as in Example 1, except that the temperature is raised to 80°C under nitrogen protection and the reaction is carried out for 10 hours. The prepared sample is marked as 3#.

[0085] Example 4

[0086] The preparation method is the same as in Example 1, except that the vacuum degree of the system is controlled at 0.01 kPa, the temperature is raised to 230°C, and the reaction is carried out for 0.5 hours. The prepared sample is marked as 4#.

[0087] Example 5

[0088] The preparation method is the same as in Example 1, except that the vacuum degree of the system is controlled at 0.5 kPa, the temperature is raised to 170°C, and the reaction is carried out for 5 hours. The prepared sample is marked as 5#.

[0089] Tests showed that during the preparation of samples 2# to 5#, the conversion rate of the transesterification reaction before vacuum distillation was between 60% and 80%; and the conversion rate of the transesterification reaction after vacuum distillation was greater than 90%.

[0090] Example 6

[0091] 20.04 g of 1,4-cyclohexanediol, 22.04 g of γ-mercaptopropyltriethoxysilane, and 0.62 g of tetraethyl titanate were added to a three-necked flask. A distillation apparatus was connected, and the mixture was heated to 150 °C under nitrogen protection with stirring, and reacted for 6 hours. A large amount of ethanol was distilled off during this process, and the conversion rate of the transesterification reaction was 77%. Then, a vacuum distillation apparatus was connected, and the reaction was carried out under reduced pressure, maintaining a vacuum of 2 kPa. The temperature was raised to 180 °C, and the reaction was stopped after one hour. The mixture was allowed to cool naturally to room temperature, and the sample was taken out and labeled #6. The conversion rate of the transesterification reaction was 92%.

[0092] Example 7

[0093] The preparation method was the same as in Example 6, except that 1,4-cyclohexanediol was replaced with 1,4-cyclohexanediethanol, and the amount added was 20.24 g; γ-mercaptopropyltriethoxysilane was replaced with both methyl orthosilicate and γ-mercaptopropyltriethoxysilane, with γ-mercaptopropyltriethoxysilane added in an amount of 10.12 g and methyl orthosilicate added in an amount of 14.05 g; tetraethyl titanate was replaced with tetrabutyl titanate, and the amount added was 0.52 g. The prepared sample was labeled 7#.

[0094] Example 8

[0095] The preparation method was the same as in Example 6, except that 1,4-cyclohexanediol was replaced with terephthalic acid, and the amount added was 27.63 g; γ-mercaptopropyltriethoxysilane was replaced with both γ-mercaptopropyltriethoxysilane and tetrapropyl silicate, with the amount of γ-mercaptopropyltriethoxysilane added being 10.12 g and the amount added being 12.18 g; tetraethyl titanate was replaced with tetraisopropyl titanate, and the amount added was 0.97 g. The prepared sample was labeled 8#.

[0096] Example 9

[0097] The preparation method is the same as in Example 6, except that 1,4-cyclohexanediol is replaced by 1,4-cyclohexanediol and 2,2,4,4-tetramethyl-1,3-cyclobutanediol, both of which are added in an amount of 10.03 g; γ-mercaptopropyltriethoxysilane is replaced by γ-mercaptopropyltrimethoxysilane, with an addition amount of 11.28 g; the prepared sample is labeled as 9#.

[0098] Example 10

[0099] The preparation method is the same as in Example 6, except that tetraethyl titanate is replaced with tetraisooctyl titanate, and the amount added is 0.83g. The prepared sample is marked as 10#.

[0100] Example 11

[0101] 20.02 g of microcrystalline cellulose, 31.13 g of γ-mercaptopropyltrimethoxysilane, and 0.46 g of tetraethyl titanate were added to a three-necked flask. A distillation apparatus was connected, and the mixture was heated to 120 °C under nitrogen protection with stirring, and reacted for 8 hours. A large amount of ethanol was distilled off during this process, and the transesterification conversion rate was 73%. Then, a vacuum distillation apparatus was connected, and the reaction was carried out under reduced pressure, maintaining a vacuum of 1 kPa. The temperature was raised to 220 °C, and the reaction was stopped after one hour. The mixture was allowed to cool naturally to room temperature, and the sample was removed and labeled #11. The transesterification conversion rate was 96%.

[0102] Test Example 1

[0103] Mercury adsorption was tested on the samples prepared in Examples 1 to 11: a certain amount of mercapto resin was added to prepared aqueous solutions of mercury ions of different concentrations (≈1 ppm), and the concentration of the solution after adsorption was tested using a Haiguang HGF-V2 atomic fluorescence spectrophotometer.

[0104] Formula for calculating mercury ion removal rate:

[0105] Mercury ion removal rate % = (Mercury ion concentration in solution before adsorption - Mercury ion concentration in solution after adsorption) / Mercury ion concentration in solution before adsorption * 100%.

[0106] The adsorption results are shown in Table 1. It can be seen that after adsorption of sample #11, the concentration of mercury ions in the solution decreased from 1064 ppb to 17.6 ppb, and the removal rate of mercury ions reached up to 98.35%. The polymerized mercury resin has a strong mercury ion adsorption capacity.

[0107] The test results for samples 1# to 10# are similar to those described above.

[0108] Table 1. Mercury adsorption results of samples 1-11# in Examples 1-3

[0109]

[0110] Test Example 2

[0111] Thermogravimetric analysis was performed on the samples prepared in Examples 1 to 11: the temperature was increased to 800°C at a heating rate of 10°C / min, and the analysis was performed under the condition of nitrogen flow rate of 100 ml / min.

[0112] Taking sample 5# as an example, the typical results of the thermogravimetric curve are as follows: Figure 1 As shown in the figure, sample 5# decomposes at 200℃, indicating that γ-mercaptopropyltrimethoxysilane, one of the raw materials, exists as an end group on the polymer. This temperature is its decomposition temperature, proving that a large number of mercaptopropyl groups not attached to the main chain exist, which is one of the important reasons why the resin has excellent heavy metal adsorption performance. It decomposes at 400℃, and the synthesized mercapto resin has a high thermal decomposition temperature, which also proves that the raw materials have successfully polymerized through transesterification reaction to form a mercapto resin with good thermal stability.

[0113] The test results for samples 1# to 10# are similar to those described above.

[0114] Test Example 3

[0115] The adsorption selectivity of heavy metal ions was tested on the samples prepared in Examples 1-11. A certain amount of mercapto resin was added to aqueous solutions of mercury ions, lead ions, and cadmium ions at different concentrations (all concentrations ≈ 8 ppm). After adsorption, the concentration of the solution after adsorption was tested by ICP-OES.

[0116] Formulas for calculating the adsorption capacity of various metal ions:

[0117] Metal ion adsorption capacity (mg / g) = (concentration of the metal ion in the solution before adsorption - concentration of the metal ion in the solution after adsorption) * volume of adsorption liquid / mass of adsorbent.

[0118] The adsorption results are as follows Figure 2 As shown, samples 5 and 11 both exhibit high adsorption capacity for mercury ions, but weaker adsorption capacity for lead and cadmium ions, demonstrating selective adsorption capacity for mercury ions.

[0119] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A mercapto resin, characterized in that, The chemical formula of the thiol resin includes structural units as shown in Formula I: Where n = 0 to 3, m = 1 to 20, and R1 is H or cyano.

2. The method for preparing the thiol resin according to claim 1, characterized in that, Includes the following steps: The thiol resin is prepared by transesterification of a mixture containing titanate, polyol and thiol silicate.

3. The preparation method according to claim 2, characterized in that, The molar ratio of the titanate to the polyol and mercaptosilicate is 1:(30-600):(20-200).

4. The preparation method according to claim 2, characterized in that, The titanate is selected from at least one of compounds having the chemical formula shown in Formula II: R2, R3, R4, and R5 are independently selected from C1 to C8 alkyl groups; Preferably, the titanate includes at least one of tetraethyl titanate, tetrabutyl titanate, tetraisopropyl titanate, tetrahexyl titanate, and tetraisooctyl titanate.

5. The preparation method according to claim 2, characterized in that, The mixture also includes silicates; The silicate ester is from at least one of compounds having the structure shown in Formula III: R6, R7, R8, and R9 are independently selected from C1 to C4 alkyl groups; Preferably, the silicate ester is selected from at least one of methyl silicate, tetraethyl silicate, tetrapropyl silicate, and tetrabutyl silicate; Preferably, the molar ratio of the titanate to the polyol, mercaptosilicate, and silicate is 1:100-500:100-500:100-500.

6. The preparation method according to claim 2, characterized in that, The mercaptosilicate is selected from at least one of compounds having the chemical formula shown in Formula IV: Among them, R 10 R 11 R 13 Independently selected from one of methyl, methoxy, and ethoxy, R 12 Select one of the structures shown in formula V: Where n = 0 to 3, and R1 is H or cyano; Preferably, R 12 Selected from one of mercaptoethyl, mercaptopropylthiocyanopropyl, and ethylthio; Preferably, the mercaptosilicone ester is selected from at least one of (ethylthio)trimethylsilane, 3-thiocyanopropyltrimethoxysilane, 3-cyanopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and 2-mercaptoethyltriethoxysilane.

7. The preparation method according to claim 2, characterized in that, The conditions for the transesterification reaction include: the reaction process is carried out in an inactive atmosphere, the reaction temperature is 80-180℃, and the reaction time is 2-20h.

8. The preparation method according to claim 2, characterized in that, The preparation method further includes: performing vacuum distillation after the reaction; Preferably, the conditions for vacuum distillation include: a vacuum degree of 0.01–5 kPa, a vacuum distillation temperature of 170–230 °C, and a vacuum distillation time of 0.5–5 h.

9. The preparation method according to claim 2, characterized in that, The number of hydroxyl groups in the polyol is greater than or equal to 2; Preferably, the polyol is selected from at least one of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol 1000, polyethylene glycol 2000, polyethylene glycol 4000, polyethylene glycol 6000, polyethylene glycol 8000, polyethylene glycol 10000, 1,4-cyclohexanediol, 1,4-cyclohexanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, terephthalic acid, glycerol, trimethylolpropane, pentaerythritol, xylitol, and sorbitol.

10. The application of the thiol resin according to claim 1 or the thiol resin prepared by the preparation method according to any one of claims 2 to 9 as a heavy metal adsorbent in wastewater treatment.

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