Preparation method and application of ion absorption gel for water treatment

Abstract

The invention discloses a preparation method and application of ion absorption gel for water treatment, and belongs to the field of circulating water. According to the cleaning and scale inhibiting hydrogel containing the glycyrrhizic acid natural component, the low-concentration calcium ion absorption effect of the ion absorption hydrogel prepared from glycyrrhizic acid reaches 31.8%, and the high-concentration calcium ion absorption effect of the ion absorption hydrogel prepared from glycyrrhizic acid reaches 40%; and the ion absorption hydrogel can be kept stable for a long time under the conditions of low salt concentration and high salt concentration. On the basis that the raw materials are environmentally friendly, the scale inhibitor has excellent metal ion adsorption capacity and stability, and powerful support is provided for improving the performance of the scale inhibitor and reducing adverse effects on the environment.

Description

Technical Field

[0001] The invention relates to a preparation method and application of ion absorption gel for water treatment, belonging to the field of circulating water. Background Art

[0002] With the development of the economy and society, various industries have developed rapidly. The suspended solids and microorganisms in the resulting industrial wastewater also have adverse effects on human health and cooling water systems. These interrelated problems can be divided into four categories: scaling, corrosion, biofouling (sludge and sludge), and microbial growth and accumulation. Control of these four problems is necessary to maintain the good operation of the system. For this reason, the development of a clean and efficient anti-scaling hydrogel has always been the focus of attention in the field of water system applications.

[0003] Antiscalants are a chemical substance or a mixture of several chemical substances that can prevent or inhibit the formation of scale. The main function of antiscalants is to inhibit scale. Antiscaling: by chelating metal ions in water, it prevents them from combining with anions in water to form scale. These antiscalants have good antiscaling and corrosion inhibition capabilities, which help to effectively reduce scaling and damage to equipment during circulating water operation.

[0004] However, traditional scale inhibitors have some defects. For example, many traditional scale and corrosion inhibitors contain phosphorus. These phosphorus compounds can serve as a nutrient source for microorganisms, causing the growth of water microorganisms, leading to eutrophication of water bodies, and further exacerbating microbial corrosion of pipe networks; copolymer scale inhibitors are difficult to be degraded by microorganisms, and long-term accumulation will also cause water pollution and endanger human health. In recent years, the environmental protection of clean scale inhibitors has gradually attracted people's attention. Polymeric clean scale inhibitors have shown obvious advantages in many fields such as industrial production due to their environmental protection, high efficiency, biodegradability, synergistic effect, cost reduction, strong adaptability and continuous innovative research and development direction.

[0005] At the same time, there are also certain problems in the use of polymeric antiscalants. Many polymeric antiscalant products contain non-cleaning monomers, which may cause environmental pollution when used; when developing new environmentally friendly antiscalants and corrosion inhibitors, the need to maintain high efficiency will inevitably lead to high prices; in order to ensure that there is no secondary pollution to the water body, it is necessary to ensure that the antiscalant products used have high-quality stability, which has become a difficult problem that is still difficult to solve.

[0006] Therefore, the preparation of an efficient and stable polymeric cleaning inhibitor is an important goal to be overcome in this field. This will not only help to increase the production capacity of factories with water systems, but also reduce the adverse effects on freshwater and marine environments, and achieve a virtuous cycle of industrial water use and environmental protection. Summary of the invention

[0007] In order to solve the problems of low sustainability, environmental impact and cost of traditional polymer scale inhibitors, the present invention provides a clean scale inhibitor hydrogel containing natural organic acid ingredients. With its rich metal chelating ability and stability, it becomes an innovative solution to overcome the above problems and provides strong support for improving the performance of corrosion inhibitors and reducing adverse effects on the environment.

[0008] The first object of the present invention is to provide a method for preparing an ion-absorbing hydrogel, comprising the steps of:

[0009] (1) dissolving methacrylic acid in an organic acid solution, adding a cross-linking agent N,N-methylenebisacrylamide, mixing, and heating to obtain a mixed solution;

[0010] In the mixed solution, the mass ratio of methacrylic acid, organic acid and cross-linking agent is 8-10 g: 0.1-0.9 g: 0.01-0.1 g;

[0011] (2) adding potassium persulfate as an initiator to the mixed solution, mixing and stirring, and drying to obtain an ion absorbing hydrogel.

[0012] In one embodiment, the organic acid in step (1) comprises one of glycyrrhizic acid, ursolic acid, asiatic acid, oleanolic acid, hawthorn acid and betulinic acid;

[0013] Preferably, the organic acid is glycyrrhizic acid.

[0014] In one embodiment, the heating treatment in step (1) is performed by heating to 32-35°C and maintaining for 1.5-2 hours, then cooling to 20-25°C and maintaining for 3.5-4 hours, and the cycle is repeated 1-2 times.

[0015] In one embodiment, the heating treatment in step (1) is to raise the temperature to 35°C and maintain it for 2 hours, then lower the temperature to 25°C and maintain it for 4 hours, and the cycle is repeated 1 to 2 times.

[0016] In one embodiment, the drying in step (2) is performed at 55-60°C for 4-5 hours, and then the temperature is raised to 75-80°C for 1-2 hours.

[0017] In one embodiment, the drying in step (2) is performed at 55-60° C. for 4 hours, and then the temperature is increased to 80° C. for 1-2 hours.

[0018] The second object of the present invention is to provide an ion-absorbing hydrogel prepared by any of the above methods.

[0019] The third object of the present invention is to provide the use of any of the above methods or the above ion-absorbing hydrogels in the preparation of scale-inhibiting water treatment materials.

[0020] The fourth object of the present invention is to provide an antiscalant, which comprises the above-mentioned ion-absorbing hydrogel or is prepared from the above-mentioned ion-absorbing hydrogel.

[0021] A fifth object of the present invention is to provide a method for simultaneously improving the calcium ion adsorption effect and stability of the ion-absorbing hydrogel, the method comprising the steps of:

[0022] (1) dissolving methacrylic acid in an organic acid solution, adding a cross-linking agent N,N-methylenebisacrylamide, mixing and stirring to obtain a mixed solution;

[0023] In the mixed solution, the mass ratio of methacrylic acid, organic acid and cross-linking agent is 8-10 g: 0.1-0.9 g: 0.01-0.1 g;

[0024] (2) adding potassium persulfate as an initiator to the mixed solution, mixing and stirring, and drying to obtain an ion absorbing hydrogel.

[0025] In one embodiment, the organic acid in step (1) comprises one of glycyrrhizic acid, ursolic acid, asiatic acid, oleanolic acid, hawthorn acid and betulinic acid;

[0026] Preferably, the organic acid is glycyrrhizic acid.

[0027] In one embodiment, the heating treatment in step (1) is performed by heating to 32-35°C and maintaining for 1.5-2 hours, then cooling to 20-25°C and maintaining for 3.5-4 hours, and the cycle is repeated 1-2 times.

[0028] In one embodiment, the heating treatment in step (1) is to raise the temperature to 35°C and maintain it for 2 hours, then lower the temperature to 25°C and maintain it for 4 hours, and the cycle is repeated 1 to 2 times.

[0029] In one embodiment, the drying in step (2) is performed at 55-60°C for 4-5 hours, and then the temperature is raised to 75-80°C for 1-2 hours.

[0030] In one embodiment, the drying in step (2) is performed at 55-60° C. for 4 hours, and then the temperature is increased to 80° C. for 1-2 hours.

[0031] Beneficial Effects of the Invention

[0032] The present invention provides a cleaning and scale-inhibiting hydrogel containing natural organic acid ingredients, which has rich metal chelating ability and stability, specifically:

[0033] (1) The ion absorption hydrogel prepared by glycyrrhizic acid in the present invention has an absorption effect of 31.8% for low concentration (1-10 mg / L) calcium ions and an absorption effect of 40% for high concentration (1-10 g / L) calcium ions;

[0034] (2) The ion-absorbing hydrogel prepared by glycyrrhizic acid in the present invention can maintain long-term stability under low salt concentration (10 mg / L) and high salt concentration (10 g / L). BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The Fourier transform infrared spectrum of the ion absorption hydrogel prepared in Example 1;

[0036] Figure 2 The Ca content of the ion-absorbing hydrogel prepared in Example 1 after being placed at ultra-low concentration for three days 2+ Absorption of Ca (25°C); Sample numbers 1 to 5 correspond to Ca (1, 3, 5, 7, 10 mg / L) after three days of exposure. 2+ absorption of

[0037] Figure 3 The Ca content of the ion-absorbing hydrogel prepared in Example 1 after being placed under ultra-high concentration for three days 2+ The absorption of samples No. 1 to 5 respectively correspond to the absorption of samples No. 1, No. 3, No. 5, No. 7, No. 10 after three days of exposure to 1, 3, 5, 7, and 10 g / L of Ca 2+ absorption of

[0038] Figure 4 This is a photo of the appearance of the dry glycyrrhizic acid-ion absorption hydrogel prepared in Example 1;

[0039] Figure 5 High concentration of Ca 2+ at 10 g / L 2+ The appearance stability of the ion-absorbing hydrogel prepared in Example 1 after being immersed in the solution for one week;

[0040] Figure 6 For high concentrations of Ca at 10 g / L 2+ The appearance stability of the ion-absorbing hydrogel prepared in Example 1 after being immersed in the solution for one month;

[0041] Figure 7 Appearance stability of the ion-absorbing hydrogel prepared in Example 1 after being immersed in deionized water for one month. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0043] The invention provides a methacrylic acid polymer cleaning scale inhibitor (i.e. ion absorption hydrogel). The methacrylic acid polymer cleaning scale inhibitor is prepared from methacrylic acid, organic acid, N,N methylenebisacrylamide and an initiator.

[0044] Among them, organic acids include glycyrrhizic acid, ursolic acid, asiatic acid, oleanolic acid, hawthorn acid, and betulinic acid;

[0045] Preferably, the organic acid is glycyrrhizic acid.

[0046] When the ion-absorbing hydrogel is prepared with glycyrrhizic acid, methacrylic acid, N,N-methylenebisacrylamide and an initiator, the groups of the following formula (1) and formula (2) are linked to each other through covalent bonds.

[0047]

[0048] Since glycyrrhizic acid has a large steric hindrance, the prepared hydrogel has a porous structure, which can ensure that the calcium and magnesium ions in the water that cause scale formation can be efficiently absorbed and chelated on the chelating sites of the hydrogel. At the same time, because the polymerization of methacrylic acid hydrogel is a covalent bond link, it has excellent stability and no sol phenomenon occurs in water for a long time, which is very suitable for industrial production and other fields.

[0049] The raw materials used in the examples are:

[0050] Glycyrrhizic acid was purchased from: Aladdin, CAS: 1405-86-3;

[0051] Ursolic acid was purchased from: Aladdin, CAS: 77-52-1;

[0052] Centella asiatica was purchased from: Aladdin, CAS: 464-92-6;

[0053] Oleanolic acid was purchased from: Aladdin, CAS: 508-02-1;

[0054] Maslinic acid was purchased from: Aladdin, CAS: 4373-41-5;

[0055] Betulinic acid was purchased from: MacLean, CAS: 472-15-1;

[0056] Citric acid was purchased from: Aladdin, CAS: 77-92-9;

[0057] Maleic acid was purchased from: Aladdin, CAS: 110-16-7;

[0058] Methacrylic acid was purchased from: Aladdin, CAS: 79-41-4;

[0059] N,N-methylenebisacrylamide was purchased from: Aladdin, CAS: 110-26-9;

[0060] Potassium persulfate was purchased from Aladdin, CAS: 7727-21-1.

[0061] Test method:

[0062] Fourier transform infrared spectroscopy:

[0063] Dry the hydrogel and grind the dried solid sample into powder together with KBr; complete the instrument debugging, turn on the instrument according to the instructions, calibrate the light source and detector, measure the system delay time, and set the scanning parameters; then place the sample in the sample chamber in the infrared beam; then perform a baseline measurement to calibrate the instrument; then record the sample spectrum and record the absorption by scanning infrared light of different wave numbers; analyze the data after collection to identify the characteristic peaks and fingerprint areas, and determine the structure of the compound in combination with other data.

[0064] Example 1: Preparation of ion-absorbing hydrogel using glycyrrhizic acid

[0065] 1. A method for preparing an ion-absorbing hydrogel, comprising the steps of:

[0066] (1) 8 g of methacrylic acid was dissolved in 15 mL of a 0.0067 g / mL glycyrrhizic acid solution, and 0.01 g of a cross-linking agent N,N-methylenebisacrylamide was added and mixed. The mixture was heated and cooled at 25°C to 35°C, maintained at 35°C for 2 h, and then cooled to 25°C and maintained for 4 h. The mixture was cycled 1 to 2 times and stirred thoroughly to obtain a mixed solution.

[0067] (2) 0.01 g of initiator KPS (potassium persulfate) was added to the mixed solution, and the mixture was stirred at room temperature for 1 h. The mixture was placed in an oven at 60 °C for 4 h, and then heated to 80 °C for further drying for 2 h to prepare 7 g of ion-absorbing hydrogel.

[0068] Infrared spectra of ion-absorbing hydrogels Figure 1 shown. Figure 1 3436.4cm appears in -1 The stretching vibration absorption peak and 1385.5cm -1 The bending vibration peak at 1650cm -1 ~1700cm -1 There is no absorption peak in the interval, indicating that there is no free carbon-carbon double bond, that is, the ion-absorbing hydrogel is successfully cross-linked.

[0069] 2. Ion absorption hydrogel performance test

[0070] (1) Calcium ion absorption effect at low concentration

[0071] The ion-absorbing hydrogel (7.32 g) prepared in 1 was placed in Ca 2+ The Ca content in aqueous solution was detected three days before and after the solution was tested at concentrations of 1, 3, 5, 7, and 10 mg / L. 2+ The results are as follows: Figure 2As shown, the results show that after being placed in the hydrogel, the Ca 2+ The concentration decreased significantly. On the 7th day, Ca 2+ The concentrations decreased by 50%, 66.7%, 50%, 40% and 40% respectively.

[0072] (2) Calcium ion absorption effect at high concentration

[0073] The ion-absorbing hydrogel (7.32 g) prepared in 1 was placed in Ca 2+ The Ca content in aqueous solution was detected three days before and after the solution was tested at concentrations of 1, 3, 5, 7, and 10 g / L. 2+ The results are as follows: Figure 3 As shown in the figure, the results show that after the ion absorption hydrogel is placed, the Ca 2+ The concentration decreased significantly. On the 7th day, Ca 2+ The concentrations decreased by 60%, 68%, 54%, 40% and 44% respectively.

[0074] (3) Stability under high salt conditions

[0075] The ion-absorbing hydrogel (7.32 g) prepared in 1 was placed in a Ca 2+ The stability of the ion-absorbing hydrogel under high salt concentration conditions was tested by soaking it in a solution with a concentration of 10 g / L for one month. Figure 4 , Figure 5 , Figure 6 As shown, the results indicate that the ion-absorbing hydrogel can remain stable for a long time in high-concentration salt solutions.

[0076] (4) Water absorption and swelling stability

[0077] The ion-absorbing hydrogel (7.32 g) prepared in step 1 was immersed in deionized water for one month to test the water absorption and swelling stability of the ion-absorbing hydrogel in deionized water. Figure 7 As shown, the results indicate that the ion-absorbing hydrogel can remain stable for a long time under deionized water conditions.

[0078] The above results show that the ion-absorbing hydrogel prepared in Example 1 can maintain long-term stability under deionized water and high-salt conditions, and can have good particle absorption effects under low-salt and high-salt conditions.

[0079] Example 2: Preparation of ion-absorbing hydrogel using ursolic acid

[0080] On the basis of Example 1, glycyrrhizic acid was replaced by ursolic acid, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0081] Example 3: Preparation of ion-absorbing hydrogel using asiatic acid

[0082] On the basis of Example 1, glycyrrhizic acid was replaced with asiatic acid, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0083] Example 4: Preparation of ion-absorbing hydrogel using oleanolic acid

[0084] On the basis of Example 1, glycyrrhizic acid was replaced by oleanolic acid, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0085] Example 5: Preparation of ion-absorbing hydrogel using hawthorn acid

[0086] On the basis of Example 1, glycyrrhizic acid was replaced by maslinic acid, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0087] Example 6: Preparation of ion-absorbing hydrogel using betulinic acid

[0088] On the basis of Example 1, glycyrrhizic acid was replaced by betulinic acid, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0089] Example 7: Preparation of ion-absorbing hydrogel using linolenic acid

[0090] On the basis of Example 1, glycyrrhizic acid was replaced by linolenic acid, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0091] Comparative Example 1: Preparation of ion-absorbing hydrogel using small molecule organic acid

[0092] On the basis of Example 1, glycyrrhizic acid was replaced by citric acid, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0093] Comparative Example 2: Preparation of ion-absorbing hydrogel using small molecule organic acid

[0094] On the basis of Example 1, glycyrrhizic acid was replaced by maleic acid, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0095] Comparative Example 3: No glycyrrhizic acid added

[0096] On the basis of Example 1, glycyrrhizic acid was not added, and the remaining steps were consistent with Example 1 to prepare the ion absorption hydrogel.

[0097] Comparative Example 4: Changing the timing of adding glycyrrhizic acid

[0098] The preparation sequence of the ion absorbing hydrogel is changed to include the steps of:

[0099] (1) 8 g of methacrylic acid and 0.1 g of a cross-linking agent, N,N-methylenebisacrylamide, were mixed and dissolved in 15 mL of a 0.006 g / mL glycyrrhizic acid solution, and the mixture was heated and cooled at 25° C. to 35° C. (the mixture was heated to 35° C. and maintained for 2 h, then cooled to 25° C. and maintained for 4 h, and the mixture was cycled 1 to 2 times) and stirred to obtain a mixed solution;

[0100] (2) 0.01 g of initiator KPS (potassium persulfate) was added to the mixed solution, and the mixture was stirred at room temperature for 1 h. The mixture was placed in an oven at 60 °C for 4 h, and then heated to 80 °C for further drying for 2 h to prepare 8.1 g of ion-absorbing hydrogel.

[0101] Comparative Example 5: Changing the timing of adding glycyrrhizic acid

[0102] The preparation sequence of the ion absorbing hydrogel is changed to include the steps of:

[0103] (1) 8 g of methacrylic acid and 0.1 g of a cross-linking agent, N,N-methylenebisacrylamide, were mixed, and the mixture was heated and cooled in a cycle from 25°C to 35°C (after heating to 35°C for 2 hours, the mixture was cooled to 25°C for 4 hours, and the mixture was cycled 1 to 2 times), stirred thoroughly, and then dissolved in 15 mL of a 0.006 g / mL glycyrrhizic acid solution to obtain a mixed solution;

[0104] (2) 0.01 g of initiator KPS (potassium persulfate) was added to the mixed solution, and the mixture was stirred at room temperature for 1 h. The mixture was placed in an oven at 60 °C for 4 h, and then heated to 80 °C for further drying for 2 h to prepare 8 g of ion-absorbing hydrogel.

[0105] Comparative Example 6: Changing the amount of glycyrrhizic acid added

[0106] On the basis of Example 1, the concentration of glycyrrhizic acid was changed to 0.9 g / mL (too high concentration), and the remaining steps were consistent with Example 1 to prepare the ion-absorbing hydrogel.

[0107] Comparative Example 7: Changing the amount of glycyrrhizic acid added

[0108] On the basis of Example 1, the concentration of glycyrrhizic acid was changed to 0.001 g / mL (the concentration was too low), and the remaining steps were consistent with Example 1 to prepare the ion-absorbing hydrogel.

[0109] Example 7: Ion absorption hydrogel performance test

[0110] The ion absorption hydrogels prepared in Examples 1 to 6 and Comparative Examples 1 to 6 were tested for Ca 2+ Absorption capacity (i.e., detection of residual Ca in the environment) 2+ The results are shown in Table 1.

[0111] Table 1 Ca under high and low salt concentrations 2+ Absorption capacity

[0112]

[0113]

[0114] Comparing Examples 1 to 6 and Comparative Examples 1 to 7, it can be seen that the organic acids selected in the Examples have better adsorption effects on calcium ions than the Comparative Examples. Among them, glycyrrhizic acid has excellent Ca absorption compared with ursolic acid, asiatic acid, oleanolic acid, hawthorn acid, betulinic acid and linolenic acid. 2+ Ion absorption capacity; at the same time, the preparation order and parameters also have a great influence on the calcium ion absorption performance of ion-absorbing hydrogel.

[0115] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing an ion-absorbing hydrogel, characterized in that: Includes steps: (1) dissolving methacrylic acid in an organic acid solution, adding a cross-linking agent N,N-methylenebisacrylamide, mixing, and heating to obtain a mixed solution; In the mixed solution, the mass ratio of methacrylic acid, organic acid and cross-linking agent is 8-10 g: 0.1-0.9 g: 0.01-0.1 g; (2) adding potassium persulfate as an initiator to the mixed solution, mixing and stirring, and drying to obtain an ion absorbing hydrogel.

2. The method according to claim 1, characterized in that In step (1), the organic acid comprises one of glycyrrhizic acid, ursolic acid, asiatic acid, oleanolic acid, hawthorn acid and betulinic acid; Preferably, the organic acid is glycyrrhizic acid.

3. The method according to claim 1, characterized in that: The heating treatment in step (1) is to raise the temperature to 32-35°C and maintain it for 1.5-2h, then lower the temperature to 20-25°C and maintain it for 3.5-4h, and repeat it 1-2 times.

4. The method according to claim 1, characterized in that: In step (2), the drying is performed at 55-60° C. for 4-5 hours, and then the temperature is raised to 75-80° C. for 1-2 hours.

5. The ion-absorbing hydrogel prepared by the method according to any one of claims 1 to 4.

6. Use of the method according to any one of claims 1 to 4 or the ion-absorbing hydrogel according to claim 5 in the preparation of scale-inhibiting water treatment materials.

7. A scale inhibitor, characterized in that: The scale inhibitor comprises the ion-absorbing hydrogel according to claim 5, or is prepared from the ion-absorbing hydrogel according to claim 5.

8. A method for simultaneously improving the calcium ion adsorption effect and stability of an ion-absorbing hydrogel, characterized in that: The method comprises the steps of: (1) dissolving methacrylic acid in an organic acid solution, adding a cross-linking agent N,N-methylenebisacrylamide, mixing and stirring to obtain a mixed solution; In the mixed solution, the mass ratio of methacrylic acid, organic acid and cross-linking agent is 8-10 g: 0.1-0.9 g: 0.01-0.1 g; (2) adding potassium persulfate as an initiator to the mixed solution, mixing and stirring, and drying to obtain an ion absorbing hydrogel.

9. The method according to claim 8, characterized in that In step (1), the organic acid comprises one of glycyrrhizic acid, ursolic acid, asiatic acid, oleanolic acid, hawthorn acid and betulinic acid; Preferably, the organic acid is glycyrrhizic acid.

10. The method according to claim 8, characterized in that In step (1), the heating treatment is to raise the temperature to 32-35°C and maintain it for 1.5-2 hours, then lower the temperature to 20-25°C and maintain it for 3.5-4 hours, and repeat it 1-2 times; In step (2), the drying is performed at 55-60° C. for 4-5 hours, and then the temperature is raised to 75-80° C. for 1-2 hours.

Images