Method for photocatalysis of waste PET plastic and sulfite into hydroxymethyl sulfonate by using Pt-loaded TiO2 catalyst

Abstract

The invention relates to a method for preparing hydroxymethyl sulfonate from waste PET (polyethylene terephthalate) plastic and sulfite through photocatalysis by a Pt-loaded TiO2 catalyst, which is characterized in that PET is degraded through hydrolysis reaction to generate monomers TPA and EG (ethylene glycol). Adding dilute sulfuric acid to neutralize the solution to separate out TPA, and filtering the TPA to collect a pure EG aqueous solution. The invention also provides a preparation method of the Pt loaded TiO2 catalyst. The Pt-loaded TiO2 catalyst prepared by the method provided by the invention is used for photocatalysis of EG and a sulfite solution to generate a C-S coupling reaction, and a product HMS is generated. EG is oxidized into formaldehyde through the Pt-loaded TiO2 catalyst, the formaldehyde and SO3 < 2-> can be spontaneously subjected to an addition reaction to generate HMS, the system has very high HMS yield, and the selectivity of HMS is greater than 72%. The method not only contributes to resource utilization of the PET waste plastics, but also provides a feasible scheme for green photosynthesis of the HMS.

Description

Technical Field

[0001] This invention relates to the technical field of industrial catalysis, specifically to the preparation of Pt-supported TiO2 catalysts and a method for photocatalytically converting waste PET plastic and sulfite into hydroxymethylsulfonate. Particularly, it relates to TiO2 with different Pt loadings (Pt... x The TiO2 (x = 0.05–0.7%) catalyst reacts polyethylene glycol (EG) monomers derived from polyethylene terephthalate (PET) with sulfites (SO3). 2- The highly efficient photocatalyst is hydroxymethyl sulfonate (HMS). Background Technology

[0002] Organosulfur compounds are widely distributed in natural ecosystems and various organisms, with over a thousand such compounds identified and extracted from terrestrial and aquatic environments. These compounds play a crucial role in the development of anticancer, anticonvulsant, and antibacterial drugs. Currently, the market for organosulfur compounds is experiencing sustained growth and is expected to continue expanding at a significant compound annual growth rate, including both natural and synthetic varieties. These compounds continue to have a profound impact on new drug discovery, highlighting their key role in driving advancements in medical science and other related fields. Hydroxymethyl sulfonate (HMS), as one of the simplest organosulfur compounds, not only functions as an important cleaning agent in the electronics industry but also serves as a key intermediate in the synthesis of surfactants and pharmaceuticals. Its industrial synthesis is typically carried out via the nucleophilic addition reaction of formaldehyde with bisulfite, but this process can generate byproducts such as polyoxymethylene (POM) and poses a potential cancer risk to workers. Therefore, developing a more environmentally friendly HMS production strategy is of great significance. In recent years, several innovative technological routes have been developed to combine biomass alcohols with bisulfite (SO3) via a catalytic CS coupling reaction. 2- ) or bisulfite (HSO3) - Combined with other methods to prepare HMS. For example, using a photocatalyst to in-situ photo-oxidize alcohols to formaldehyde, while SO3... 2- As an S-containing nucleophile, it immediately undergoes an addition reaction with formaldehyde to generate HMS. Due to the mild reaction conditions, controllable parameters, and good atom economy, this photocatalytic synthesis technology for HMS shows promise as an environmentally friendly alternative.

[0003] Polyethylene terephthalate (PET) is produced globally at a rate of approximately 70 million tons per year, making it one of the most widely used polymers. About 60% of PET is used in the production of synthetic fibers, such as carpets, while approximately 30% is used to manufacture disposable beverage bottles. Depolymerizing PET into its monomers via hydrolysis is considered one of the most promising depolymerization methods, a process that converts PET into terephthalic acid (TPA) and ethylene glycol (EG). TPA can be used to further synthesize new PET plastics, while PET-derived EG can be photo-oxidized to formaldehyde, which can serve as a raw material for the synthesis of hydroxymethyl sulfonate (HMS). Therefore, designing efficient photocatalysts to stabilize and capture the formaldehyde intermediate during the photooxidation of ethylene glycol is crucial for achieving the reaction of PET-derived EG with SO3. 2- The efficient photocatalytic conversion of waste into HMS, as a dual waste treatment strategy, has significant value-added potential and environmental significance. Summary of the Invention

[0004] To address the issues of low activity and selectivity in photocatalytic HMS, this invention prepares a Pt-supported TiO2 catalyst for the production of EG and SO3 derived from PET. 2- HMS is a medium- and high-efficiency photocatalyst.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing a Pt-supported TiO2 catalyst includes the following steps:

[0007] 1) Disperse TiO2 in an aqueous methanol solution and sonicate; dilute H2PtCl6 with H2O to prepare an aqueous H2PtCl6 solution; purge the TiO2 dispersion and H2PtCl6 solution with Ar gas;

[0008] 2) Stir the TiO2 dispersion while irradiating it with a 300W xenon lamp light source;

[0009] 3) After the TiO2 dispersion turned blue, H2PtCl6 aqueous solution was injected into the TiO2 dispersion and stirred. The reaction solution was then centrifuged and washed with water and ethanol. The product was dried overnight to obtain the Pt-supported TiO2 catalyst.

[0010] In step 1 above, 1–10 mg / mL TiO2, preferably 3–8 mg / mL TiO2, is dispersed in a 20%–80%, preferably 40%–60% methanol aqueous solution and sonicated for 10–50 min, preferably 20–30 min.

[0011] In step 1 above, H2PtCl6 is diluted with H2O to prepare an aqueous solution of H2PtCl6 (1 mg / mL to 10 mg / mL), preferably 3 mg / mL to 7 mg / mL; the TiO2 dispersion and H2PtCl6 solution are purged with Ar gas for 10 to 50 min, preferably 20 to 30 min.

[0012] In step 2 above, the TiO2 dispersion is stirred at 200-800 rpm, preferably 400-600 rpm, while being irradiated with a 300W xenon lamp light source for 20-50 min, preferably 30-40 min.

[0013] In step 3 above, after the TiO2 dispersion turns blue, an aqueous solution of H2PtCl6 is injected into the TiO2 dispersion and stirred for 10 to 50 minutes, preferably 20 to 40 minutes. Then, the reaction solution is centrifuged and washed with water and ethanol 1 to 5 times, preferably 2 to 4 times.

[0014] In step 3 above, the product is dried overnight at 50–80°C, preferably 60–70°C, to obtain TiO2 (Pt) with different Pt loadings. x / TiO2 (x = 0.05-0.7%)) catalyst, with a Pt loading of 0.05-0.7 wt%, preferably 0.1-0.5 wt%.

[0015] The method of the present invention provides a Pt-supported TiO2 catalyst for the photocatalytic conversion of waste PET plastic and sulfite to HMS, comprising the following steps:

[0016] 1) Waste PET plastic is added to NaOH solution for hydrolysis to degrade PET, generating monomers TPA and EG; then, TPA is precipitated by adding dilute sulfuric acid, and pure EG solution is obtained by filtration; subsequently, sulfite is added to the EG solution to prepare EG / SO3. 2- Mixed solutions;

[0017] 2) Add Pt-supported TiO2 catalyst to EG / SO3 2- In a mixed solution, after introducing an Ar atmosphere at room temperature, a photocatalytic reaction was carried out using a 300W xenon lamp under simulated sunlight conditions to produce HMS.

[0018] In the method for synthesizing HMS, in step 1, the amount of waste PET plastic added is 10 g / L to 100 g / L, preferably 20 g / L to 80 g / L in NaOH solution.

[0019] In the method for synthesizing HMS, in step 1, waste PET plastic is added to 1M-5M alkaline solution at a temperature of 60℃-150℃ for hydrolysis reaction for 1-4 days. The pH is adjusted to 7-8 with dilute sulfuric acid to obtain monomer TPA and pure EG solution.

[0020] In the method for synthesizing HMS, SO3 is added to the EG solution in step 1. 2- The concentration is 0.05M to 0.2M.

[0021] Preferably, at a temperature of 70℃ to 120℃, 2 g / L to 8 g / L of polyester PET is added to a 2M to 4M alkaline solution and subjected to a hydrolysis reaction for 2 to 3 days.

[0022] The TPA monomer is separated to obtain a pure EG solution by neutralizing the solution with 0.1M dilute sulfuric acid to a pH of 7-8.

[0023] It is preferable to mix sodium sulfite with pure EG solution, SO3 2- The concentration is 0.1M to 0.15M.

[0024] In the method for synthesizing HMS, step 2 involves adding 0.1–1 mg / mL Pt-supported TiO2 catalyst and EG / SO3 at room temperature. 2- In the mixed solution.

[0025] Preferably, 0.2 mg / mL to 0.8 mg / mL Lpt supported TiO2 catalyst is added to EG / SO3 at room temperature. 2- In the mixed solution.

[0026] In the method for synthesizing HMS, step 2 involves phototreatment under an Ar atmosphere for 12 to 36 hours, preferably 20 to 28 hours.

[0027] This invention involves contacting waste PET plastic with an alkaline solution to hydrolyze and degrade PET, producing monomers TPA and EG. Dilute sulfuric acid is added to neutralize the solution and precipitate TPA. The TPA is then filtered to collect a pure EG aqueous solution. Subsequently, a Pt-supported TiO2 catalyst photocatalyzes a CS-coupled reaction between EG and a sulfite solution, producing the product HMS. The Pt-supported TiO2 catalyst oxidizes EG to formaldehyde, which then reacts with SO3. 2- HMS can spontaneously undergo an addition reaction to generate HMS. This method not only helps in the resource utilization of waste polyester PET plastics, but also provides a feasible solution for green photosynthesis of HMS.

[0028] The purpose of this application is to develop a highly efficient, green, and energy-saving catalytic system to achieve the reaction of PET-derived EG and SO3 in a photocatalytic reaction. 2-The conversion and CS coupling reaction highly actively generate HMS. This system not only exhibits a high HMS yield (2.7 mmol g), but also... cat -1 h -1 Furthermore, the selectivity of HMS is greater than 72%.

[0029] Compared with the prior art, this application has at least the following beneficial effects:

[0030] 1. Low cost and simple preparation: The Pt-supported TiO2 catalyst prepared by this invention has the characteristics of simple preparation process, short time and low energy consumption.

[0031] 2. Highly Efficient and Green Conversion: This invention enables the synthesis of HMS from PET-derived EG and sulfite via photocatalytic reaction under environmental conditions. The entire process is simple, environmentally friendly, avoids the use of toxic reagents, and produces no CO2 or SO3. 2- emission.

[0032] 3. High-yield generation of HMS: This invention utilizes a Pt-supported TiO2 catalyst to generate PET-derived EG and SO3. 2- This system efficiently converts HMS into high-value HMS. It not only boasts a high HMS yield (2.7 mmol g / L), but also... cat -1 h -1 Meanwhile, the selectivity of HMS is greater than 72%. Attached Figure Description

[0033] Figure 1 The Pt-supported TiO2 catalyst provided in Example 3 reacts PET-derived EG and SO3 via a photocatalytic CS coupling reaction. 2- A schematic diagram of the conversion to HMS.

[0034] Figure 2 Aberration-corrected transmission electron microscope (TEM) image of the Pt-supported TiO2 catalyst provided in Example 3.

[0035] Figure 3 The 1H NMR spectrum of the Pt-supported TiO2 catalyst provided in Example 3 after 24 hours of photocatalysis

[0036] Figure 4 HMS yield and selectivity plots of Pt-supported TiO2 catalysts with different loadings provided in Examples 6-10. Detailed Implementation

[0037] Example

[0038] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0039] Example 1

[0040] 1) Disperse 3 mg / mL TiO2 in a 20% methanol aqueous solution and sonicate for 10 min to prepare a TiO2 dispersion; dilute H2PtCl6 with H2O to prepare an H2PtCl6 aqueous solution (10 mg / mL), and purge the TiO2 dispersion and H2PtCl6 solution with Ar gas for 20 min.

[0041] 2) Stir the TiO2 dispersion at 500 rpm and irradiate it with a 300W xenon lamp light source for 20 min.

[0042] 3) After the TiO2 dispersion turned blue, an aqueous solution of H2PtCl6 was added to the TiO2 dispersion and stirred for 20 min (Pt to TiO2 mass ratio was 0.05 wt%). The reaction solution was then centrifuged and washed once with water and ethanol. The product was dried overnight at 50 °C to obtain Pt. 0.05％ / TiO2 catalyst.

[0043] Example 2

[0044] 1) Disperse 1 mg / mL TiO2 in 20 mL of 40% methanol aqueous solution and sonicate for 20 min; dilute H2PtCl6 with H2O to prepare H2PtCl6 aqueous solution (7 mg / mL), and purge TiO2 dispersion and H2PtCl6 solution with Ar gas for 20 min.

[0045] 2) Stir the TiO2 dispersion at 400 rpm and irradiate it with a 300W xenon lamp light source for 30 min.

[0046] 3) After the TiO2 dispersion turned blue, an aqueous solution of H2PtCl6 was added to the TiO2 dispersion and stirred for 10 min (Pt to TiO2 mass ratio was 0.1 wt%). The reaction solution was then centrifuged and washed twice with water and ethanol. It was dried overnight at 60℃ to obtain Pt. 0.1％ / TiO2 catalyst.

[0047] Example 3

[0048] 1) Disperse 8 mg / mL TiO2 in 30 mL of 50% methanol aqueous solution and sonicate for 25 min. 2) Dilute H2PtCl6 with H2O to prepare an H2PtCl6 aqueous solution (3 mg / mL), and purge the TiO2 dispersion and H2PtCl6 solution with Ar gas for 25 min.

[0049] 2) Stir the TiO2 dispersion at 600 rpm and irradiate it with a 300W xenon lamp light source for 35 min.

[0050] 3) After the TiO2 dispersion turned blue, an aqueous solution of H2PtCl6 was added to the TiO2 dispersion and stirred for 50 min (Pt to TiO2 mass ratio was 0.25 wt%). The reaction solution was then centrifuged and washed three times with water and ethanol. It was dried overnight at 65℃ to obtain Pt. 0.25％ / TiO2 catalyst.

[0051] Example 4

[0052] 1) Disperse 5 mg / mL TiO2 in 40 mL of 60% methanol aqueous solution and sonicate for 30 min. 2) Dilute H2PtCl6 with H2O to prepare an H2PtCl6 aqueous solution (5 mg / mL), and purge the TiO2 dispersion and H2PtCl6 solution with Ar gas for 25 min.

[0053] 2) Stir the TiO2 dispersion at 200 rpm and irradiate it with a 300W xenon lamp light source for 40 min.

[0054] 3) After the TiO2 dispersion turned blue, an aqueous solution of H2PtCl6 was added to the TiO2 dispersion and stirred for 40 min (Pt to TiO2 mass ratio was 0.5 wt%). The reaction solution was then centrifuged and washed four times with water and ethanol. It was dried overnight at 70℃ to obtain Pt. 0.5％ / TiO2 catalyst.

[0055] Example 5

[0056] 1) Disperse 10 mg / mL TiO2 in 50 mL of 80% methanol aqueous solution and sonicate for 50 min. 2) Dilute H2PtCl6 with H2O to prepare an H2PtCl6 aqueous solution (1 mg / mL), and purge the TiO2 dispersion and H2PtCl6 solution with Ar gas for 50 min.

[0057] 2) Stir the TiO2 dispersion at 800 rpm and irradiate it with a 300W xenon lamp light source for 30 min.

[0058] 3) After the TiO2 dispersion turned blue, an aqueous solution of H2PtCl6 was added to the TiO2 dispersion and stirred for 50 min (Pt to TiO2 mass ratio was 0.7 wt%). The reaction solution was then centrifuged and washed five times with water and ethanol. It was dried overnight at 80℃ to obtain Pt. 0.7％ / TiO2 catalyst.

[0059] Example 6

[0060] 1) 40 g / L of waste PET was added to a 3M NaOH alkaline solution and hydrolyzed for 2.5 days to obtain an aqueous solution of TPA and EG monomers. Then, 0.1M dilute sulfuric acid was added to adjust the pH of the aqueous solution to 7-8, causing TPA to precipitate completely from the solution. After filtering out the TPA monomer, the pure EG solution was collected. Subsequently, sodium sulfite was added to the pure EG solution to prepare a solution containing 0.05M SO3. 2- EG solution.

[0061] 2) Photocatalytic synthesis of HMS was carried out in a 100 mL sealed glass reactor using a 300 W Xe lamp at room temperature and atmospheric pressure. 0.5 mg / mL Pt was added. 0.05％ / TiO2 catalyst added to a solution containing 0.05M SO3 2 The EG solution was used. Before irradiation, the reactor was purged with Ar to remove residual gases, and then irradiated from the top of the reaction tank. After 24 hours of irradiation, 100 μL of the liquid product and 400 μL of a deuterated aqueous solution with a maleic acid concentration of 1 mg / mL were used to prepare a sample. 1 The peak area of ​​HMS in the liquid product was determined by 1H NMR, and the yield of HMS was calculated according to the following formula (1.3 mmol g). cat -1 h -1 ):

[0062]

[0063] Where S HMS and S standard These represent the integrated areas of the peaks for maleic acid and HMS, respectively. HMSr This indicates the number of hydrogen atoms (N) in the HMS characteristic peak used for quantitative analysis. HMS =2). m standard and M standard These represent the mass and molar weight of maleic acid, respectively. V represents the volume of the reaction solution (V = 50 mL). catalytic t represents the mass of the catalyst. t represents the reaction time.

[0064] Example 7

[0065] 1) Add 10 g / L waste PET to 1 M NaOH alkaline solution and hydrolyze for 1 day to obtain an aqueous solution of TPA and EG monomers. Then add 0.1 M dilute sulfuric acid to adjust the pH of the aqueous solution to 7-8, at which point TPA will completely precipitate from the solution. After filtering out the TPA monomer, collect the pure EG solution. Then add sodium sulfite to the pure EG solution to prepare a solution containing 0.1 M SO3. 2- EG solution.

[0066] 2) Photocatalytic synthesis of HMS was carried out in a 100 mL sealed glass reactor using a 300 W Xe lamp at room temperature and atmospheric pressure. 0.1 mg / mL Pt was added. 0.1％ / TiO2 added to a solution containing 0.1M SO3 2- The EG solution was used. Before irradiation, the reactor was purged with Ar to remove residual gases, and then irradiated from the top of the reaction tank. After 12 hours of irradiation, 100 μL of the liquid product and 400 μL of a 1 mg / mL deuterated aqueous solution of maleic acid were used to prepare a sample. 1 The peak area of ​​HMS in the liquid product was determined by 1H NMR, and the yield of HMS was calculated to be (1.7 mmol g) according to the formula in Example 6. cat -1 h -1 ).

[0067] Example 8

[0068] 1) 20 g / L of waste PET was added to a 2M NaOH alkaline solution and hydrolyzed for 3 days to obtain an aqueous solution of TPA and EG monomers. Then, 0.1M dilute sulfuric acid was added to adjust the pH of the aqueous solution to 7-8, causing TPA to precipitate completely from the solution. After filtering out the TPA monomer, the pure EG solution was collected. Subsequently, sodium sulfite was added to the pure EG solution to prepare a solution containing 0.13M SO3. 2- EG solution.

[0069] 2) Photocatalytic synthesis of HMS was carried out in a 100 mL sealed glass reactor using a 300 W Xe lamp at room temperature and atmospheric pressure. 0.2 mg / mL Pt was added. 0.25％ / TiO2 is added to a mixture containing 0.13M SO3 2- The EG solution was used. Before irradiation, the reactor was purged with Ar to remove residual gases, and then irradiated from the top of the reaction tank. After 20 h of irradiation, 100 μL of the liquid product and 400 μL of a deuterated aqueous solution with a maleic acid concentration of 1 mg / mL were used to prepare a sample. 1 The peak area of ​​HMS in the liquid product was determined by 1H NMR, and the yield of HMS was calculated to be (2.7 mmol g) according to the formula in Example 6. cat -1 h-1 ).

[0070] Example 9

[0071] 1) Add 80 g / L of waste PET to 4M NaOH alkaline solution and hydrolyze for 3 days to obtain an aqueous solution of TPA and EG monomers. Then add 0.1M dilute sulfuric acid to adjust the pH of the aqueous solution to 7-8, at which point TPA will completely precipitate from the solution. After filtering out the TPA monomer, collect the pure EG solution. Then add sodium sulfite to the pure EG solution to prepare a solution containing 0.15M SO3. 2- EG solution.

[0072] 2) Photocatalytic synthesis of HMS was carried out in a 100 mL sealed glass reactor using a 300 W Xe lamp at room temperature and atmospheric pressure. 0.8 mg / mL Pt was added. 0.5％ / TiO2 catalyst added to a solution containing 0.15M SO3 2- The EG solution was used. Before irradiation, the reactor was purged with Ar to remove residual gases, and then irradiated from the top of the reaction tank. After 28 hours of irradiation, 100 μL of the liquid product and 400 μL of a deuterated aqueous solution with a maleic acid concentration of 1 mg / mL were used to prepare a sample. 1 The peak area of ​​HMS in the liquid product was determined by 1H NMR, and the yield of HMS was calculated to be 1.9 mmol g / L according to the formula in Example 6. cat -1 h -1 ).

[0073] Example 10

[0074] 1) 100 g / L of waste PET was added to a 5M NaOH alkaline solution and hydrolyzed for 4 days to obtain an aqueous solution of TPA and EG monomers. Then, 0.1M dilute sulfuric acid was added to adjust the pH of the aqueous solution to 7-8, causing TPA to precipitate completely from the solution. After filtering out the TPA monomer, the pure EG solution was collected. Subsequently, sodium sulfite was added to the pure EG solution to prepare a solution containing 0.2M SO3. 2- EG solution.

[0075] 2) Photocatalytic synthesis of HMS was carried out in a 100 mL sealed glass reactor using a 300 W Xe lamp at room temperature and atmospheric pressure. 1 mg / mL of Pt was added... 0.7％ / TiO2 catalyst added to a solution containing 0.2M SO3 2- The EG solution was used. Before irradiation, the reactor was purged with Ar to remove residual gases, and then irradiated from the top of the reaction tank. After 36 h of irradiation, 100 μL of the liquid product and 400 μL of a deuterated aqueous solution with a maleic acid concentration of 1 mg / mL were used to prepare a sample. 1The peak area of ​​HMS in the liquid product was determined by 1H NMR, and the yield of HMS was calculated to be (1.2 mmol g) according to the formula in Example 6. cat -1 h -1 ).

[0076] Performance and other test specifications

[0077] (1) The process of photocatalytic HMS generation:

[0078] Figure 1 The process of photocatalytic HMS generation in Examples 6 to 10 of the present invention is described.

[0079] EG and SO3 2- In the presence of a Pt-supported TiO2 catalyst, EG can be photocatalytically oxidized to formaldehyde. Specifically, when the Pt-supported TiO2 catalyst is photoexcited, photogenerated electron-hole pairs are generated. These photogenerated holes oxidize EG, causing C / C bond breakage and dehydrogenation to produce formaldehyde. Formaldehyde then reacts with SO3 in the solution. 2- A CS coupling reaction occurs to generate HMS.

[0080] The specific formula is: (a) CH3OH + * → *CH3OH

[0081] (b) *CH3OH→*CH3O+H + +e -

[0082] (c) *CH3O→*CH2O+H + +e -

[0083] (d)*CH2O+HSO3 - →*OHCH2SO3 -

[0084] (2) Morphological characteristics:

[0085] Figure 2 In Embodiment 3 of the present invention, Pt 0.25％ A spherical aberration-corrected transmission electron microscopy (TEM) image of the TiO2 catalyst, showing that Pt at the 5 nm scale... 0.25 The TiO2 catalyst has many bright spots. Since Pt metal has stronger contrast under aberration electron microscopy than TiO2, these bright spots can be attributed to Pt metal particles. Because this process uses methanol-water solution as the dispersion liquid, the Pt metal particles are small in size and uniformly dispersed on the TiO2 support.

[0086] (3) HMS detection:

[0087] Figure 3In Embodiment 3 of the present invention, Pt 0.25％ The 1H NMR spectrum of the / TiO2 catalyst obtained in the reaction of Example 9, when in EG / SO3 2 After 24 hours of illumination in the mixed solution, peaks for the substrate EG and the product HMS could be observed. Specifically, the peak at 3.51 ppm represented the substrate EG, and the peak at 4.22 ppm represented the product HMS. This indicates that HMS is mediated by Pt. 0.25％ / TiO2 catalyst and photocatalytic reaction obtained.

[0088] (4) Figure 1. Yield and selectivity of photocatalytic HMS for TiO2 catalysts with different Pt loadings

[0089] Figure 4 This paper compares the HMS production performance of all catalysts listed in Examples 1-5 of this invention with the corresponding reactions in Examples 6-10. The yield and selectivity of HMS were determined by proton NMR spectroscopy. Different Pt-supported TiO2 catalysts can achieve high-yield and high-selectivity photocatalytic synthesis of HMS. The HMS yields are all within 1 mmol g. cat -1 h -1 The highest yield can reach 2.7 mmol g. cat -1 h -1 The selectivity of HMS was consistently above 60%, with the highest selectivity reaching 72%.

[0090] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a Pt-supported TiO2 catalyst, characterized in that, Includes the following steps: 1) Disperse TiO2 in an aqueous methanol solution and sonicate; dilute H2PtCl6 with H2O to prepare an aqueous H2PtCl6 solution; purge the TiO2 dispersion and H2PtCl6 solution with Ar gas; 2) Stir the TiO2 dispersion while irradiating it with a 300W xenon lamp light source; 3) After the TiO2 dispersion turns blue, H2PtCl6 aqueous solution is injected into the TiO2 dispersion and stirred. The reaction solution is then centrifuged and washed with water and ethanol. The product is dried overnight to obtain Pt-supported TiO2 catalyst.

2. The preparation method according to claim 1, characterized in that, In step 1), 1-10 mg / mL TiO2 is dispersed in a 20%-80% methanol aqueous solution and sonicated for 10-50 min; H2PtCl6 is diluted with H2O to prepare a 1-10 mg / mL H2PtCl6 aqueous solution; the TiO2 dispersion and H2PtCl6 solution are purged with Ar gas for 10-50 min.

3. The preparation method according to claim 1, characterized in that, In step 2), the TiO2 dispersion is stirred at 200-800 rpm and irradiated with a 300W xenon lamp light source for 20-50 minutes.

4. The preparation method according to claim 1, characterized in that, In step 3), after the TiO2 dispersion turns blue, H2PtCl6 aqueous solution is injected into the TiO2 dispersion and stirred for 10-50 min. The reaction solution is then centrifuged and washed with water and ethanol 1-5 times. The product was dried overnight at 50–80°C to obtain Pt. x / TiO2 catalyst, x = 0.05~0.7%.

5. A method for photocatalytically converting waste PET plastic and sulfite to HMS using the Pt-supported TiO2 catalyst prepared according to claim 1, comprising the following steps: 1) Waste PET plastic is added to NaOH alkaline solution for hydrolysis to degrade PET, generating monomers TPA and EG; then, TPA is precipitated by adding dilute sulfuric acid, and pure EG solution is obtained by filtration; subsequently, sulfite is added to the EG solution to prepare EG / SO3. 2- Mixed solutions; 2) Add Pt-supported TiO2 catalyst to EG / SO3 2- In a mixed solution, after introducing an Ar atmosphere at room temperature, a photocatalytic reaction was carried out using a 300W xenon lamp under simulated sunlight conditions to produce HMS.

6. The method for synthesizing HMS as described in claim 5, characterized in that, In step 1, the amount of waste PET plastic added is 10g / L to 100g / L.

7. The method for photocatalytically converting waste PET plastic and sulfite to HMS as described in claim 5, characterized in that, In step 1), waste PET plastic is added to 0.1M to 5M alkaline solution at a temperature of 60℃ to 150℃ for hydrolysis for 1 to 4 days. The pH is adjusted to 7 to 8 with dilute sulfuric acid to obtain monomer TPA and pure EG solution.

8. The method for photocatalytically converting waste PET plastic and sulfite to HMS as described in claim 5, characterized in that, In step 1), sodium sulfite is mixed with pure EG solution, SO3 2- The concentration is 0.05M to 0.2M.

9. The method for photocatalytically converting waste PET plastic and sulfite to HMS as described in claim 5, characterized in that, In step 2), 0.2 mg / mL to 0.8 mg / mL Pt is added at room temperature. x / TiO2 catalyst to EG / SO3 2- In the mixed solution.

10. The method for photocatalytically converting waste PET plastic and sulfite to HMS as described in claim 5, characterized in that, In step 2), the light treatment is carried out in an argon atmosphere for 12 to 36 hours.

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