Preparation and usage method of a molecular sieve for adsorbing formaldehyde

Abstract

The present invention relates to a preparation method and a use method of a molecular sieve for adsorbing formaldehyde. The preparation method includes the following steps: (1) preparing a carrier of the molecular sieve; (2) preparing a load of the molecular sieve; (3) preparing the molecular sieve. The use method includes the following steps: putting the prepared molecular sieve into the wastewater containing formaldehyde according to the amount of the wastewater containing formaldehyde in proportion, then adding dilute hydrochloric acid to the wastewater to adjust the pH, and then adjusting the reaction temperature, and reacting for 6d - 7d to achieve the purpose of adsorbing formaldehyde in the wastewater. As a crystalline material with a porous structure, the pore size of the molecular sieve can be accurately controlled at the molecular level, so it can selectively adsorb formaldehyde (HCHO) molecules with a smaller molecular weight. While the molecular sieve efficiently adsorbs formaldehyde, it retains the carbon source to the greatest extent and has high industrial application value.

Description

Technical Field

[0001] The present invention relates to the technical field of organic wastewater treatment, and in particular to a preparation method and a use method of a molecular sieve for adsorbing formaldehyde. Background Art

[0002] The World Health Organization's International Agency for Research on Cancer (IARC) has pointed out that formaldehyde can cause cancer in humans. Research shows that formaldehyde is a substance with relatively high toxicity. Short-term exposure to formaldehyde can irritate the eyes, nasal cavity and respiratory tract and cause allergic reactions; long-term exposure to low-dose formaldehyde can increase the likelihood of nasopharyngeal cancer, leukemia and death.

[0003] The patent with the application number 202011383902.X discloses a catalyst for removing formaldehyde and carbon monoxide at room temperature and its preparation method. However, the catalyst can only have a good treatment effect on formaldehyde under the condition of room temperature, which is not conducive to its industrial application; the patent with the application number 201711278261.X discloses a Cu-OMS-2 catalyst that can effectively remove formaldehyde in a real environment and its preparation method. Although it can catalytically oxidize and degrade formaldehyde in a real gas environment containing water vapor, it can only treat formaldehyde present in the gas medium and does not record whether it can treat formaldehyde present in the liquid medium.

[0004] Due to the characteristics of formaldehyde in organic wastewater, such as being difficult to decompose, highly toxic, and having poor biodegradability, traditional biochemical technologies are difficult to meet the treatment standards. Therefore, in recent years, many new treatment processes for formaldehyde-containing wastewater have emerged. As an improvement of the traditional homogeneous Fenton technology, the heterogeneous Fenton technology has shown excellent results in treating such wastewater. By using this method, harmful components such as organic pollution gases and low-concentration formaldehyde in the water environment can be effectively removed. Since the hydroxyl radicals generated during the heterogeneous Fenton oxidation reaction process are highly oxidizing, it inevitably leads to the oxidation and degradation of organic substances in the wastewater that are easily biodegradable, thereby indirectly increasing the cost and wasting the carbon source. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the present invention provides a preparation method and a use method of a molecular sieve for adsorbing formaldehyde. The present invention can selectively adsorb formaldehyde efficiently while retaining the carbon source to the greatest extent, and has high industrial application value.

[0006] The technical solution of the present invention is as follows: A preparation method of a molecular sieve for adsorbing formaldehyde, and the steps are as follows:

[0007] (1) Prepare the carrier of the molecular sieve

[0008] First, dissolve 0.4 - 0.6 g, preferably 0.55 g of KMnO4 in 10 - 15 ml, preferably 10 ml of deionized water. Then transfer the KMnO4 aqueous solution to an autoclave. With stirring, add dropwise to the KMnO4 aqueous solution 20.0 - 21.0 ml, preferably 21.0 ml of a sulfuric acid anhydrous solution containing 0.8 - 0.9 g, preferably 0.8 g of MnSO4·3H2O;

[0009] Subsequently, seal the autoclave and maintain it at 100 °C - 120 °C for 8 h - 12 h. After cooling to room temperature, a black product is obtained. Finally, centrifuge, wash, and dry the black product to obtain the carrier of the molecular sieve;

[0010] (2) Preparation of the loaded substance of the molecular sieve

[0011] First, dissolve 0.6 - 0.8 g, preferably 0.75 g of PVP and 0.1 - 0.2 g, preferably 0.16 g of sodium citrate in 80 ml - 100 ml, preferably 100 ml of deionized water and transfer it to a three-necked flask;

[0012] Then stir in a water bath at 60 °C - 80 °C, and then add dropwise to the reaction system 0.5 - 1.0 ml, preferably 0.6 ml of an aqueous solution of chloroplatinic acid. After stirring for 4 - 6 min, add dropwise to the reaction system 8 ml - 10 ml, preferably 10 ml of an aqueous solution containing 0.1 - 0.2 g, preferably 0.15 g of ascorbic acid, and stir for 4 - 8 min;

[0013] Add dropwise 10 ml - 12 ml of an aqueous solution containing 0.01 - 0.03 g of copper acetate to the reaction system. After stirring for 5 - 7 min, then add dropwise 4 ml - 6 ml of an aqueous solution containing 0.01 - 0.05 g of cobalt nitrate to the reaction system. After reacting for 1 - 1.5 h, the loaded substance of the molecular sieve can be obtained;

[0014] (3) Preparation of the molecular sieve

[0015] First, disperse the carrier prepared in step (1) in 30 ml - 50 ml of deionized water by ultrasonic wave, then add the mixed solution to the three-necked flask in step (2) and mix it evenly with the loaded substance prepared in step (2). Subsequently, react in a water bath at 60 °C - 80 °C for 4 - 6 h;

[0016] After the reaction, filter to obtain a precipitate, then wash the precipitate, and finally dry it at 60 °C - 80 °C for 12 h - 15 h to obtain the molecular sieve.

[0017] Furthermore, the concentration of the aqueous solution of chloroplatinic acid is 20 mg / mL - 25 mg / mL.

[0018] Further, the cleaning solvent described in steps (1) and (3) is deionized water and ethanol with a ratio of 4-5:1.

[0019] Further, the drying temperature in step (1) is 50°C - 70°C, and the drying time is 8h - 12h.

[0020] A method for using a molecular sieve for adsorbing formaldehyde, the steps of which are as follows: Put the molecular sieve prepared in claim 1 into the wastewater containing formaldehyde according to the amount of the wastewater containing formaldehyde, then add dilute hydrochloric acid to the wastewater to adjust the pH, and then adjust the reaction temperature, and react for 6d - 7d to achieve the purpose of adsorbing formaldehyde in the wastewater.

[0021] Further, the dosage of the molecular sieve is 12g / L - 20g / L, preferably 15g / L.

[0022] Further, the pH is 3.5 - 4.5, preferably 4.

[0023] Further, the temperature is 55°C - 75°C, preferably 65°C.

[0024] The beneficial technical effects of the present invention are as follows:

[0025] The molecular sieve for adsorbing formaldehyde provided by the present invention is a crystalline material with a porous structure, and its pore size can be accurately controlled at the molecular level. Therefore, it can selectively adsorb formaldehyde (HCHO) molecules with a smaller molecular weight. The function of the molecular sieve is mainly achieved through two ways: physical adsorption and chemical adsorption. Physical adsorption means that because there are a large number of tiny pores and a large adsorption surface area inside the molecular sieve, it has good physical adsorption ability and can directly adsorb formaldehyde molecules into its interior; chemical adsorption means that for the molecular sieve loaded with single atoms of Pt, Cu, and Co, it can react with formaldehyde through an oxidation reaction to convert formaldehyde into carbon dioxide to achieve the purpose of treating formaldehyde.

[0026] Experimental data prove that the selective adsorption efficiency of the molecular sieve of the present invention for formaldehyde can reach more than 99%. At the same time, the retention rate of the carbon source is as high as 94%, and it shows excellent performance in terms of repeatability and selectivity. While efficiently adsorbing formaldehyde, it retains the carbon source to the greatest extent and has high industrial application value.

[0027] The molecular sieve for adsorbing formaldehyde provided by the present invention adopts a method combining selective adsorption technology and heterogeneous Fenton technology, highly selectively adsorbing target pollutants onto the catalyst material and degrading them, thus forming a highly selective heterogeneous Fenton technology. Compared with the traditional Fenton method, the process of the present invention is simple, low in cost, mild in operating conditions, and does not require the addition of external oxidants or reductants. By using this method, harmful components such as organic polluted gases and low-concentration formaldehyde in the water environment can be efficiently and low-energy-consumingly eliminated, and at the same time, the problem of secondary pollution is avoided, providing a new idea and approach for the treatment of formaldehyde wastewater. In addition, this catalytic system also has good application prospects in the treatment of other organic pollutants.

[0028] Compared with the traditional formaldehyde treatment methods, the catalytic oxidation method of the present invention has the advantages of high efficiency and low toxicity, can realize continuous operation, and has mild reaction conditions and low energy consumption, being more suitable for industrial application. Compared with granular and powdered catalysts, the molecular sieve prepared by the present invention is not restricted in morphology and shows excellent effects in the removal of formaldehyde. In addition, the molecular sieve prepared by the present invention also exhibits certain in-situ regeneration ability, and even after catalytic degradation, its adsorption performance is hardly affected, demonstrating its excellent catalytic activity. Description of the Drawings

[0029] Figure 1 Graph showing the relationship between the conversion rate of formaldehyde and temperature when the molecular sieve prepared in Examples 1-6 is used to treat formaldehyde.

[0030] Figure 2 Graph showing the relationship between the conversion rate of glucose and time when the molecular sieve prepared in Example 5 is repeated five times. Detailed Embodiments

[0031] The present invention will be specifically described below in conjunction with the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Example 1:

[0033] This example provides a preparation method of a molecular sieve for adsorbing formaldehyde, in which the mass ratio of Pt, Cu, and Co is Pt(2wt%) : Cu(0wt%) : Co(0wt%), and its preparation method is as follows:

[0034] (1) Prepare the carrier of the molecular sieve

[0035] First, dissolve 0.4 g of KMnO4 in 10 ml of deionized water, then transfer the KMnO4 aqueous solution to an autoclave. Under stirring, add 20.0 ml of a sulfuric acid-free aqueous solution containing 0.8 g of MnSO4·3H2O dropwise to the KMnO4 aqueous solution. Subsequently, seal the autoclave and maintain it at 100 °C for 8 h. After cooling to room temperature, a black product is obtained. Finally, centrifuge the black product, wash it with deionized water and ethanol, and dry it at 60 °C for 12 h to obtain the support of the molecular sieve.

[0036] (2) Preparation of the loading substance of the molecular sieve

[0037] First, dissolve 0.6 g of PVP and 0.1 g of sodium citrate in 80 ml of deionized water and transfer it to a three-necked flask; stir vigorously in a 60 °C water bath and add 0.5 ml of an aqueous solution of chloroplatinic acid (H2PtCl6·36H2O) (20 mg / mL) dropwise; after stirring for another 4 minutes, add 8 ml of an aqueous solution containing 0.1 g of ascorbic acid dropwise to the mixture solution; after reacting for 1 h, the loading substance of the molecular sieve can be obtained.

[0038] (3) Preparation of the molecular sieve

[0039] Disperse 0.6 g of the support in 30 ml of deionized water by ultrasonic waves and add it to a three-necked flask; after reacting in a 60 °C water bath for 4 h, filter the precipitate and wash it several times with deionized water and ethanol to remove any possible residual reactants; dry the product at 60 °C for 12 h to obtain the molecular sieve.

[0040] Example 2:

[0041] This example provides a preparation method of a molecular sieve for adsorbing formaldehyde, in which the mass ratio of Pt, Cu, and Co is Pt (0 wt%) : Cu (1 wt%) : Co (1 wt%). The preparation method is as follows:

[0042] (1) Preparation of the support of the molecular sieve

[0043] First, dissolve 0.6 g of KMnO4 in 15 ml of deionized water, then transfer the KMnO4 aqueous solution to an autoclave. Under stirring, add 21.0 ml of a sulfuric acid-free aqueous solution containing 0.9 g of MnSO4·3H2O dropwise to the KMnO4 aqueous solution. Subsequently, seal the autoclave and maintain it at 120 °C for 12 h. After cooling to room temperature, a black product is obtained. Finally, centrifuge the black product, wash it with deionized water and ethanol, and dry it at 60 °C for 12 h to obtain the support of the molecular sieve.

[0044] (2) Preparation of the loading substance of the molecular sieve

[0045] Dissolve 0.8 g of PVP and 0.2 g of sodium citrate in 100 ml of deionized water and transfer it to a three-necked flask; stir vigorously in a water bath at 80 °C, and add 12 ml of an aqueous solution containing 0.019 g of copper acetate dropwise to the mixture solution; after stirring for another 5 minutes, add 5 ml of an aqueous solution containing 0.018 g of cobalt nitrate dropwise to the mixture solution; after reacting for 1 h, the supported material of the molecular sieve can be prepared.

[0046] (3) Prepare the molecular sieve

[0047] Disperse 0.6 g of the carrier in 50 ml of deionized water by ultrasonic wave and add it to a three-necked flask; after reacting in a water bath at 80 °C for 4 h, filter the precipitate and wash it several times with deionized water and ethanol to remove any possible residual reactants; dry the product at 60 °C for 12 h to obtain the molecular sieve.

[0048] Example 3:

[0049] This example provides a preparation method of a molecular sieve for adsorbing formaldehyde, where the mass ratio of Pt, Cu, and Co is Pt(2 wt%):Cu(0 wt%):Co(1 wt%), and its preparation method is as follows:

[0050] (1) Prepare the carrier of the molecular sieve

[0051] First, dissolve 0.55 g of KMnO4 in 10 ml of deionized water, then transfer the KMnO4 aqueous solution to an autoclave, and while stirring, add 21.0 ml of a concentrated sulfuric acid aqueous solution containing 0.8 g of MnSO4·3H2O dropwise to the KMnO4 aqueous solution. Subsequently, seal the autoclave and keep it at 120 °C for 12 h. After cooling to room temperature, a black product is obtained. Finally, centrifuge the black product, wash it with deionized water and ethanol, and dry it at 60 °C for 12 h to obtain the carrier of the molecular sieve.

[0052] (2) Prepare the supported material of the molecular sieve

[0053] Dissolve 0.75 g of PVP and 0.16 g of sodium citrate in 100 ml of deionized water and transfer it to a three-necked flask; stir vigorously in a water bath at 80 °C, and add 0.6 ml of an aqueous solution of chloroplatinic acid (H2PtCl6·36H2O) (20 mg / mL) dropwise; after stirring for another 5 minutes, add 10 ml of an aqueous solution containing 0.15 g of ascorbic acid dropwise to the mixture solution; after stirring for another 5 minutes, add 5 ml of an aqueous solution containing 0.018 g of cobalt nitrate dropwise to the mixture solution; after reacting for 1 h, the supported material of the molecular sieve can be prepared.

[0054] (3) Prepare the molecular sieve

[0055] Disperse 0.6 g of the carrier in 50 mL of deionized water by ultrasonic waves and add it to a three-necked flask; after reacting in a water bath at 80 °C for 4 hours, filter the precipitate and wash it several times with deionized water and ethanol to remove any possible residual reactants; dry the product at 60 °C for 12 hours to obtain the molecular sieve.

[0056] Example 4:

[0057] This example provides a method for preparing a molecular sieve for adsorbing formaldehyde, where the mass ratio of Pt, Cu, and Co is Pt(2 wt%) : Cu(1 wt%) : Co(0 wt%), and its preparation method is as follows:

[0058] (1) Prepare the carrier of the molecular sieve

[0059] First, dissolve 0.55 g of KMnO4 in 10 ml of deionized water, then transfer the KMnO4 aqueous solution to an autoclave. While stirring, add 21.0 ml of a concentrated sulfuric acid aqueous solution containing 0.8 g of MnSO4·3H2O dropwise to the KMnO4 aqueous solution. Subsequently, seal the autoclave and maintain it at 120 °C for 12 h. After cooling to room temperature, obtain a black product. Finally, centrifuge the black product, wash it with deionized water and ethanol, and dry it at 60 °C for 12 h to obtain the carrier of the molecular sieve;

[0060] (2) Prepare the loading of the molecular sieve

[0061] Dissolve 0.75 g of PVP and 0.16 g of sodium citrate in 100 ml of deionized water and transfer it to a three-necked flask; stir vigorously in a water bath at 80 °C and add 0.6 ml of an aqueous solution of chloroplatinic acid (H2PtCl6·36H2O) (20 mg / mL) dropwise; after stirring for another 5 minutes, add 10 ml of an aqueous solution containing 0.15 g of ascorbic acid dropwise to the mixture solution; after reacting for 1 h, obtain the loading of the molecular sieve;

[0062] (3) Prepare the molecular sieve

[0063] Disperse 0.6 g of the carrier in 50 mL of deionized water by ultrasonic waves and add it to a three-necked flask; after reacting in a water bath at 80 °C for 4 hours, filter the precipitate and wash it several times with deionized water and ethanol to remove any possible residual reactants; dry the product at 60 °C for 12 hours to obtain the molecular sieve.

[0064] Example 5:

[0065] This embodiment provides a preparation method of a molecular sieve for adsorbing formaldehyde, wherein the mass ratio of Pt, Cu, and Co is Pt(2wt%): Cu(1wt%): Co(1wt%), and its preparation method is as follows:

[0066] (1) Prepare the carrier of the molecular sieve

[0067] First, dissolve 0.55 g of KMnO4 in 10 ml of deionized water, then transfer the KMnO4 aqueous solution to an autoclave. Under stirring, add 21.0 ml of a concentrated sulfuric acid aqueous solution containing 0.8 g of MnSO4·3H2O dropwise to the KMnO4 aqueous solution. Subsequently, seal the autoclave and keep it at 120 °C for 12 h. After cooling to room temperature, a black product is obtained. Finally, centrifuge the black product, wash it with deionized water and ethanol, and dry it at 60 °C for 12 h to obtain the carrier of the molecular sieve;

[0068] (2) Prepare the loading substance of the molecular sieve

[0069] Dissolve 0.75 g of PVP and 0.16 g of sodium citrate in 100 ml of deionized water and transfer it to a three-necked flask; stir vigorously in an 80 °C water bath and add 0.6 ml of an aqueous solution of chloroplatinic acid (H2PtCl6·36H2O) (20 mg / mL) dropwise; after stirring for another 5 minutes, add 10 ml of an aqueous solution containing 0.15 g of ascorbic acid dropwise to the mixture solution; after stirring for another 5 minutes, add 10 ml of an aqueous solution containing 0.03 g of copper acetate dropwise to the mixture solution; after stirring for another 5 minutes, add 5 ml of an aqueous solution containing 0.05 g of cobalt nitrate dropwise to the mixture solution; after reacting for 1 h, the loading substance of the molecular sieve can be obtained;

[0070] (3) Prepare the molecular sieve

[0071] Disperse 0.6 g of the carrier in 50 ml of deionized water by ultrasonic wave and add it to a three-necked flask; after reacting in an 80 °C water bath for 4 h, filter the precipitate, wash it several times with deionized water and ethanol to remove any possible residual reactants, and dry the product at 60 °C for 12 h to obtain the molecular sieve.

[0072] Example 6:

[0073] This embodiment provides a preparation method of a molecular sieve for adsorbing formaldehyde, wherein the mass ratio of Pt, Cu, and Co is Pt(0wt%): Cu(0wt%): Co(0wt%), and its preparation method is as follows:

[0074] (1) Prepare the carrier of the molecular sieve

[0075] First, dissolve 0.55 g of KMnO4 in 10 ml of deionized water, then transfer the KMnO4 aqueous solution to an autoclave. Under stirring, add 21.0 ml of a concentrated sulfuric acid anhydrous solution containing 0.8 g of MnSO4·3H2O dropwise to the KMnO4 aqueous solution. Subsequently, seal the autoclave and maintain it at 120 °C for 12 h. After cooling to room temperature, a black product is obtained. Finally, centrifuge the black product, wash it with deionized water and ethanol, and dry it at 60 °C for 12 h to obtain the carrier of the molecular sieve.

[0076] (2) Preparation of the loading of the molecular sieve

[0077] Dissolve 0.75 g of PVP and 0.16 g of sodium citrate in 100 ml of deionized water and transfer it to a three-necked flask; stir vigorously in an 80 °C water bath and add 0.6 ml of deionized water dropwise; after stirring for another 5 minutes, add 10 ml of deionized water dropwise to the mixture solution; after stirring for another 5 minutes, add 5 ml of deionized water dropwise to the mixture solution; after reacting for 1 h, the loading of the molecular sieve can be obtained.

[0078] (3) Preparation of the molecular sieve

[0079] Disperse 0.6 g of the carrier in 50 ml of deionized water by ultrasonic waves and add it to a three-necked flask; after reacting in an 80 °C water bath for 4 h, filter the precipitate and wash it several times with deionized water and ethanol to remove any possible residual reactants; dry the product at 60 °C for 12 h to obtain the molecular sieve.

[0080] Detection Example 1:

[0081] Apply the molecular sieves prepared in Examples 1-6 to the treatment of formaldehyde-containing wastewater respectively. The specific method is as follows:

[0082] Add the molecular sieves prepared in Examples 1-6 to the formaldehyde-containing wastewater at a rate of 15 g / L respectively, then add dilute hydrochloric acid to adjust the pH of the mixed solution to pH = 4, adjust the reaction temperature to 20 - 100 °C, and react for 7 h; before and after the reaction, use the acetylacetone spectrophotometric method to measure the concentration of formaldehyde in the wastewater respectively. The formaldehyde conversion rate calculation formula is: Formaldehyde conversion rate (%) = (c0 - c) / c0 × 100%; where c0 is the concentration of formaldehyde in the solution before the reaction (mg / L); c is the concentration of formaldehyde after the reaction ends (mg / L). The test results are as Figure 1 shown.

[0083] Detection Example 2:

[0084] Conduct 5 repeated experiments on the molecular sieve prepared in Example 5. The specific method is as follows:

[0085] Add 100 mL of 100 mg / L formaldehyde and 100 mL of 100 mg / L glucose solution into the conical flask respectively, that is, the mass ratio of formaldehyde to glucose is 1:1. Put the molecular sieve loaded with Pt, Cu, and Co with a mass ratio of 2:1:1 prepared in Example 5 into the above conical flask. The dosage of the molecular sieve is 15 g / L, adjust the solution pH = 4, place it in a constant temperature oscillator at 65 °C for reaction, take samples every hour within six hours, measure the concentration of glucose, and the test results are as Figure 2 shown.

[0086] Table 1 shows the mass ratios of Pt, Cu, and Co respectively loaded on the molecular sieves prepared in Examples 1-6.

[0087] Table 1

[0088] Experimental Example Content of Pt (wt%) Content of Cu (wt%) Content of Co (wt%) Example 1 2 0 0 Example 2 0 1 1 Example 3 2 0 1 Example 4 2 1 0 Example 5 2 1 1 Example 6 0 0 0

[0089] When the molecular sieves prepared in Examples 1-6 are used to treat the wastewater containing formaldehyde, the treatment ability of formaldehyde is as Figure 1 shown. It can be seen from the figure that the molecular sieves prepared in Examples 1-5 are loaded with different contents of Pt, Cu, and Co. When treating the wastewater containing formaldehyde, the conversion rate of formaldehyde first increases with the increase of temperature, and after reaching the highest point, it tends to be stable. When the molecular sieve prepared in Example 5 is used to treat the wastewater containing formaldehyde, the conversion rate of formaldehyde reaches the highest point at 70 °C, and the conversion rate of formaldehyde reaches 99%, and the effect of decomposing formaldehyde is remarkable.

[0090] The molecular sieve prepared in Example 6 is not loaded with Pt, Cu, and Co. When treating the wastewater containing formaldehyde, the conversion rate of formaldehyde does not change with the increase of temperature. Until the temperature rises to 60 °C, the conversion rate of formaldehyde begins to increase slowly, and the conversion rate of formaldehyde is only 20% at 100 °C. The overall conversion rate is lower than that of the molecular sieves prepared in Examples 1-5.

[0091] From Figure 2 it can be seen that the five repeated experiments show that the conversion rate of glucose first increases and then tends to be stable with time. The highest value of the glucose conversion rate is about 4%, which proves that the molecular sieve prepared in Example 5 will not degrade glucose.

[0092] In summary, a molecular sieve for adsorbing formaldehyde of the present invention has a remarkable effect on treating formaldehyde in wastewater, can reach the maximum value of the formaldehyde decomposition rate at a relatively low temperature, and has high selectivity while effectively degrading formaldehyde and will not catalytically degrade carbon sources such as glucose, which can significantly reduce the usage amount of chemical agents, thereby achieving the purpose of cost reduction and carbon source retention, and has high industrial application value.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

[0094] In addition, those skilled in the art can understand that although some of the embodiments herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present invention and forms different embodiments. For example, in the claims above, any one of the claimed embodiments can be used in any combination. The information disclosed in this background art section is only intended to deepen the understanding of the general background art of the present invention, and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art already known to those skilled in the art.

Claims

1. A method for the application of a molecular sieve in adsorbing formaldehyde, characterized in that, The method includes the following steps: Put the molecular sieve into the formaldehyde-containing wastewater according to the amount of the formaldehyde-containing wastewater, then add dilute hydrochloric acid to the wastewater to adjust the pH, and then adjust the reaction temperature. React for 6 - 7 h to achieve the purpose of adsorbing formaldehyde in the wastewater; the reaction temperature is 55°C - 75°C; The preparation method of the molecular sieve includes the following steps: (1) Prepare the carrier of the molecular sieve First, dissolve 0.4 - 0.6 g of KMnO4 in 10 - 15 mL of deionized water, then transfer the KMnO4 aqueous solution to an autoclave. Under stirring, add 20.0 - 21.0 mL of a concentrated sulfuric acid anhydrous solution containing 0.8 - 0.9 g of MnSO4∙3H2O dropwise to the KMnO4 aqueous solution; Subsequently, seal the autoclave and keep it at 100°C - 120°C for 8 h - 12 h. After cooling to room temperature, obtain a black product. Finally, centrifuge, wash, and dry the black product to obtain the carrier of the molecular sieve; (2) Prepare the loading of the molecular sieve First, dissolve 0.6 - 0.8 g of PVP and 0.1 - 0.2 g of sodium citrate in 80 mL - 100 mL of deionized water and transfer it to a three-necked flask; Then stir in a water bath at 60°C - 80°C, and then add 0.5 - 1.0 mL of an aqueous solution of chloroplatinic acid dropwise to the reaction system. After stirring for 4 - 6 min, add 8 mL - 10 mL of an aqueous solution containing 0.1 - 0.2 g of ascorbic acid dropwise to the reaction system and stir for 4 - 8 min; Then add 10 mL - 12 mL of an aqueous solution containing 0.01 - 0.03 g of copper acetate dropwise to the reaction system. After stirring for 5 - 7 min, add 4 mL - 6 mL of an aqueous solution containing 0.01 - 0.05 g of cobalt nitrate dropwise to the reaction system. After reacting for 1 - 1.5 h, the loading of the molecular sieve can be prepared; (3) Prepare the molecular sieve First, disperse the carrier prepared in step (1) in 30 mL - 50 mL of deionized water by ultrasonic wave, then add the mixed solution to the three-necked flask in step (2) and mix it evenly with the loading prepared in step (2). Subsequently, react in a water bath at 60°C - 80°C for 4 - 6 h; After the reaction, filter to obtain a precipitate, then wash the precipitate, and finally dry it at 60°C - 80°C for 12 h - 15 h to obtain the molecular sieve.

2. The method according to claim 1, characterized in that The drying temperature in step (1) is 50°C - 70°C, and the drying time is 8 h - 12 h.

3. The method according to claim 1, wherein The cleaning solvents in step (1) and step (3) are deionized water and ethanol.

4. The method according to claim 1, wherein The concentration of the aqueous solution of chloroplatinic acid in step (2) is 20 mg / mL - 25 mg / mL.

5. The method according to claim 1, characterized in that, The dosage of the molecular sieve is 12 g / L - 20 g / L.

6. The method according to claim 1, wherein The pH is 3.5 - 4.5.

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