Composition for circulating water treatment as well as preparation method and application thereof

Abstract

The invention discloses a composition for circulating water treatment and a preparation method and application thereof.The composition for circulating water treatment is prepared from, by mass, 5-10 parts of quaternized chitosan, 5-10 parts of anionic corrosion inhibitor and 1-1.5 parts of plant polyphenol. The composition disclosed by the invention is completely free of phosphorus and environment-sensitive substances and is environment-friendly, and a ternary system effectively improves the corrosion resistance and the scale inhibition performance of the circulating water treatment composition through the synergistic effect of the quaternized chitosan, the anionic corrosion inhibitor and the plant polyphenol.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a composition for treating circulating water, and a preparation method and application thereof. BACKGROUND

[0002] The main challenges faced by circulating cooling water during operation include corrosion, fouling and microbial growth. Among them, microorganisms are mainly controlled by bactericides. Corrosion and fouling are two key problems that are interrelated and have opposite trends, and mastering the balance between the two is crucial to solving these problems. Therefore, composite agents are usually used to control corrosion and fouling, and there is a synergistic effect between the components in these agents, which can more effectively play a role in corrosion and scale inhibition.

[0003] At present, the composite agents commonly used in circulating water treatment are mainly organic phosphonic acid as the main corrosion inhibitor, and phosphate needs to be added to enhance the corrosion inhibition effect when the water quality is corrosive. Even if zinc salt which can quickly form a precipitate film is used, due to its soft and easily damaged film, it still needs to be used in combination with phosphorus-containing agents. However, due to the discharge of phosphorus which can cause water eutrophication, the use of high-phosphorus agent formulations is increasingly restricted. Therefore, the development of low-phosphorus or non-phosphorus corrosion and scale inhibition formulations has become an important direction for water treatment agent research and development. Before the start of the circulating cooling water system, the system needs to be cleaned and pre-filmed. Pre-filming refers to the process of adding a pre-filming agent to the system to generate a protective film with corrosion resistance on the clean metal surface through physical and chemical action. The pre-filming scheme can be divided into two categories: one is a special formula pre-filming scheme, which has no direct relationship between its composition and the composition of the formula after daily operation, and after pre-filming, the system needs to be replaced by increasing the amount of water replacement, which is more complicated to operate and manage. At present, the special formula pre-filming scheme widely used in China is mainly a composite formula of polyphosphate and zinc salt. Although the pre-filming effect is good, the dosage of the agent is large, and the phosphorus and zinc content in the waste water after pre-filming is high, which has potential pollution risk to the environment water body. The other is a pre-filming scheme with high concentration, which is characterized by a close relationship between the composition of the pre-filming formula and the composition of the normal operation formula. After pre-filming is completed, the pre-filming agent is naturally replaced during operation, and only a low concentration of corrosion inhibitor is needed during normal operation to maintain and repair the protective film, which is relatively simple in operation and management.

[0004] Therefore, it is necessary to provide a low-phosphorus and high-efficiency corrosion and scale inhibition solution. SUMMARY

[0005] Therefore, the present application provides a composition for treating circulating water, and a preparation method and application thereof, to solve the problem of how to improve the corrosion and scale inhibition performance of the composition for treating circulating water.

[0006] To achieve the above technical purposes, the following technical solutions are adopted in the present application. In a first aspect, the present application provides a composition for circulating water treatment, comprising the following components in mass fraction: 5-10 parts of quaternary ammonium chitosan, 5-10 parts of anionic corrosion inhibitor, 1-1.5 parts of plant polyphenol.

[0007] Preferably, the plant polyphenol is tannic acid.

[0008] Preferably, the anionic corrosion inhibitor comprises molybdate and / or silicate.

[0009] Preferably, the molybdate is sodium molybdate, and the silicate is sodium silicate.

[0010] In a second aspect, the present application provides a preparation method of the composition for circulating water treatment, comprising the following steps: S1. Under stirring, drop an aqueous solution of the anionic corrosion inhibitor into a dilute acid solution of quaternary ammonium chitosan, mix uniformly, then add an aqueous solution of plant polyphenol, and perform self-assembly reaction to obtain a self-assembly composite solution; S2. Perform spray drying on the self-assembly composite solution to obtain the composition for circulating water treatment.

[0011] Preferably, the stirring speed is 8000-10000 rpm.

[0012] Preferably, the inlet temperature of the spray drying is 160-180℃, and the outlet temperature is 80-90℃.

[0013] Preferably, the temperature of the self-assembly reaction is 30-60℃.

[0014] In a third aspect, the present application provides an application of the composition for circulating water treatment as a metal pre-film agent.

[0015] In a fourth aspect, the present application provides a circulating water treatment method, comprising adding the composition for circulating water treatment into circulating water, so that the concentration of the composition in the circulating water is 20-100 mg / L.

[0016] The present application has the following beneficial effects: The composition of the present application is completely free of phosphorus and environmentally sensitive substances, and is environmentally friendly. The ternary system of the present application effectively improves the corrosion and scale inhibition performance of the circulating water treatment composition through the synergistic effect of quaternary ammonium chitosan, anionic corrosion inhibitor and plant polyphenol. Quaternary ammonium chitosan provides good dispersibility and stability, the anionic corrosion inhibitor forms a protective film, and the plant polyphenol enhances the durability and erosion resistance of the film. Each component self-assembles into a unified network structure through electrostatic attraction, hydrogen bonding and coordination, significantly improving the corrosion and scale inhibition performance, forming a dense and firm protective film, and being able to adapt to different water quality conditions. DETAILED DESCRIPTION

[0017] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0018] The present application provides a composition for circulating water treatment, comprising the following components in mass fraction: 5-10 parts of quaternary ammonium chitosan, 5-10 parts of anionic corrosion inhibitor, 1-1.5 parts of plant polyphenol.

[0019] In the present application, the quaternary ammonium chitosan has positive points, and the anionic corrosion inhibitor has negative points, which are combined by electrostatic attraction, and the plant polyphenol is combined with the quaternary ammonium chitosan and the anionic corrosion inhibitor by hydrogen bond, and finally a nanoscale composite colloidal particle is formed, which is embedded with the anionic corrosion inhibitor and the plant polyphenol and stably dispersed in water. By optimizing the amount of components, the positive and negative charges and the hydrogen bond effect are balanced to the best, the film compactness and stability are solved, and the corrosion and scale inhibition performance is improved.

[0020] The composition of the present application is completely free of phosphorus and environmentally sensitive substances, and is environmentally friendly. The components are not simply mixed, but are self-assembled into a unified network structure by electrostatic attraction, hydrogen bond and coordination effect, which can significantly improve the corrosion and scale inhibition performance, form a dense and firm protective film, and adapt to different water quality conditions.

[0021] In some embodiments, the plant polyphenol is tannic acid.

[0022] In some embodiments, the anionic corrosion inhibitor includes molybdate and / or silicate.

[0023] In some embodiments, the molybdate is sodium molybdate, and the silicate is sodium silicate.

[0024] The present application provides a preparation method of a composition for circulating water treatment, comprising the following steps: S1. Under stirring, the aqueous solution of the anionic corrosion inhibitor is added dropwise into the dilute acid solution of the quaternary ammonium chitosan, and after uniform mixing, the aqueous solution of the plant polyphenol is added, and a self-assembly reaction is carried out to obtain a self-assembly composite liquid; S2. The self-assembly composite liquid is subjected to spray drying to obtain a microspherical powder, which is the composition for circulating water treatment.

[0025] The present application realizes the formation of the self-assembly network structure and solves the problems by orderly adding dropwise and spray drying, and compared with direct mixing, the corrosion resistance and scale inhibition effect of the present application are good.

[0026] In some embodiments, the stirring speed is 8000-10000 rpm.

[0027] In some embodiments, the inlet temperature of the spray drying is 160-180°C, and the outlet temperature is 80-90°C.

[0028] In this embodiment, the drying conditions are defined to ensure the microspheres are formed and the active components are not destroyed, which is beneficial to the improvement of the corrosion and scale inhibition performance.

[0029] In some embodiments, the temperature of the self-assembly reaction is 30-60°C.

[0030] The application provides an application of a circulating water treatment composition as a metal pre-film agent.

[0031] The application provides a circulating water treatment method, which comprises adding the circulating water treatment composition into the circulating water, so that the concentration of the circulating water treatment composition in the circulating water is 20-100 mg / L.

[0032] The present solution is further described below through specific embodiments.

[0033] Embodiment 1 A circulating water treatment composition comprises the following components: 5 g of quaternary ammonium chitosan, 5 g of anionic corrosion inhibitor, and 1 g of plant polyphenol.

[0034] The preparation method of the circulating water treatment composition is as follows: S11. Raw material preparation: 5 g of quaternary ammonium chitosan (QC) is dissolved in 1000 mL of 1% acetic acid solution to obtain a dilute acid solution of quaternary ammonium chitosan; 2.5 g of sodium molybdate and 2.5 g of sodium silicate are dissolved in 100 mL of deionized water to obtain an aqueous solution of anionic corrosion inhibitor; and 1 g of tannic acid (TA) is dissolved in 20 mL of deionized water to obtain an aqueous solution of plant polyphenol; S12. Under high-speed shearing stirring at 10000 rpm, the aqueous solution of anionic corrosion inhibitor is added dropwise into the dilute acid solution of quaternary ammonium chitosan at 35°C, and after the addition is completed, the stirring is continued for 10 minutes; the aqueous solution of plant polyphenol is added dropwise into the above mixture, and after the addition is completed, the stirring is continued for 30 minutes to obtain a self-assembly composite solution; S2. The self-assembly composite solution is subjected to spray drying (inlet temperature 170°C, outlet temperature 85°C), and a microspherical powder is collected to obtain the circulating water treatment composition.

[0035] Embodiment 2 A circulating water treatment composition comprises the following components: 10 g of quaternary ammonium chitosan, 5 g of anionic corrosion inhibitor, and 1 g of plant polyphenol.

[0036] The preparation method of the circulating water treatment composition is as follows: S11. Raw material preparation, 10 g of quaternary ammonium chitosan (QC) was dissolved in 1000 mL of 1% acetic acid solution to obtain a dilute acid solution of quaternary ammonium chitosan; 2.5 g of sodium molybdate and 2.5 g of sodium silicate were dissolved in 100 mL of deionized water to obtain an aqueous solution of anionic corrosion inhibitor; 1 g of tannic acid (TA) was dissolved in 20 mL of deionized water to obtain a plant polyphenol aqueous solution; S12. Under high-speed shearing stirring at 10000 rpm, the aqueous solution of anionic corrosion inhibitor was added dropwise to the dilute acid solution of quaternary ammonium chitosan at 35°C, and stirring was continued for 10 minutes after the addition was completed. Keep stirring, add the plant polyphenol aqueous solution to the above mixture, continue stirring for 30 minutes after the addition is completed, to obtain a self-assembled composite solution; S2. The self-assembled composite solution was spray dried (import temperature 170°C, export temperature 85°C), and the microspherical powder was collected to obtain a circulating water treatment composition.

[0037] Example 3 A circulating water treatment composition includes the following components: 5 g of quaternary ammonium chitosan, 10 g of anionic corrosion inhibitor, 1 g of plant polyphenol.

[0038] The preparation method of the circulating water treatment composition is as follows: S11. Raw material preparation, 10 g of quaternary ammonium chitosan (QC) was dissolved in 1000 mL of 1% acetic acid solution to obtain a dilute acid solution of quaternary ammonium chitosan; 2.5 g of sodium molybdate and 2.5 g of sodium silicate were dissolved in 100 mL of deionized water to obtain an aqueous solution of anionic corrosion inhibitor; 1 g of tannic acid (TA) was dissolved in 20 mL of deionized water to obtain a plant polyphenol aqueous solution; S12. Under high-speed shearing stirring at 10000 rpm, the aqueous solution of anionic corrosion inhibitor was added dropwise to the dilute acid solution of quaternary ammonium chitosan at 35°C, and stirring was continued for 10 minutes after the addition was completed. Keep stirring, add the plant polyphenol aqueous solution to the above mixture, continue stirring for 30 minutes after the addition is completed, to obtain a self-assembled composite solution; S2. The self-assembled composite solution was spray dried (import temperature 170°C, export temperature 85°C), and the microspherical powder was collected to obtain a circulating water treatment composition.

[0039] Example 4 A circulating water treatment composition includes the following components: 5 g of quaternary ammonium chitosan, 10 g of anionic corrosion inhibitor, 1 g of plant polyphenol.

[0040] The preparation method of the circulating water treatment composition is as follows: S11. Raw material preparation, 5 g of quaternary ammonium chitosan (QC) was dissolved in 1000 mL of 1% acetic acid solution to obtain a dilute acid solution of quaternary ammonium chitosan; 2.5 g of sodium molybdate and 2.5 g of sodium silicate were dissolved in 100 mL of deionized water to obtain an aqueous solution of anionic corrosion inhibitor; 1.5 g of tannic acid (TA) was dissolved in 20 mL of deionized water to obtain a plant polyphenol aqueous solution; S12. Under high-speed shearing stirring at 10000 rpm, the aqueous solution of anionic corrosion inhibitor was added dropwise to the dilute acid solution of quaternary ammonium chitosan at 35°C, and stirring was continued for 10 minutes after the addition was completed. Keep stirring, add the plant polyphenol aqueous solution to the above mixture, continue stirring for 30 minutes after the addition is completed, to obtain a self-assembled composite solution; S2. The self-assembled composite solution was spray dried (import temperature 170°C, export temperature 85°C), and the microspherical powder was collected to obtain a circulating water treatment composition.

[0041] Comparative Example 1 A composition comprising the following components: 10 g of quaternary ammonium chitosan, 1 g of plant polyphenol.

[0042] The preparation method of the circulating water treatment composition is as follows: S11. Raw material preparation, 5 g of quaternary ammonium chitosan (QC) was dissolved in 1000 mL of 1% acetic acid solution to obtain a dilute acid solution of quaternary ammonium chitosan; 2.5 g of sodium molybdate and 2.5 g of sodium silicate were dissolved in 100 mL of deionized water to obtain an aqueous solution of anionic corrosion inhibitor; 1.5 g of tannic acid (TA) was dissolved in 20 mL of deionized water to obtain a plant polyphenol aqueous solution; S12. Under high-speed shearing stirring at 10000 rpm, the aqueous solution of anionic corrosion inhibitor was added dropwise to the dilute acid solution of quaternary ammonium chitosan at 35°C, and stirring was continued for 10 minutes after the addition was completed. Keep stirring, add the plant polyphenol aqueous solution to the above mixture, continue stirring for 30 minutes after the addition is completed, to obtain a self-assembled composite solution; S2. The self-assembled composite solution was spray dried (import temperature 170°C, export temperature 85°C), and the microspherical powder was collected to obtain a circulating water treatment composition.

[0043] Comparative Example 2 A circulating water treatment composition comprising the following components: 10 g of anionic corrosion inhibitor, 1 g of plant polyphenol.

[0044] The preparation method of the circulating water treatment composition is as follows: S11. Raw material preparation, 5 g of quaternary ammonium chitosan (QC) was dissolved in 1000 mL of 1% acetic acid solution to obtain a dilute acid solution of quaternary ammonium chitosan; 2.5 g of sodium molybdate and 2.5 g of sodium silicate were dissolved in 100 mL of deionized water to obtain an aqueous solution of anionic corrosion inhibitor; 1.5 g of tannic acid (TA) was dissolved in 20 mL of deionized water to obtain a plant polyphenol aqueous solution; S12. The plant polyphenol aqueous solution was added dropwise into the anionic corrosion inhibitor aqueous solution under high-speed shearing stirring at 10000 rpm at 35°C, and stirring was continued for 30 minutes after the dropwise addition was completed to obtain a self-assembled composite solution. S2. The self-assembled composite solution was subjected to spray drying (inlet temperature 170°C, outlet temperature 85°C), and a microspherical powder was collected to obtain a circulating water treatment composition.

[0045] Comparative Example 3 A circulating water treatment composition comprising the following components: 5.5 g of quaternary ammonium chitosan, 5.5 g of an anionic corrosion inhibitor.

[0046] The preparation method of the circulating water treatment composition is as follows: S11. Preparation of raw materials, 5.5 g of quaternary ammonium chitosan (QC) was dissolved in 1000 mL of 1% acetic acid solution to obtain a dilute acid solution of quaternary ammonium chitosan; 2.75 g of sodium molybdate and 2.75 g of sodium silicate were dissolved in 100 mL of deionized water to obtain an anionic corrosion inhibitor aqueous solution; S12. The anionic corrosion inhibitor aqueous solution was added dropwise into the dilute acid solution of quaternary ammonium chitosan under high-speed shearing stirring at 10000 rpm at 35°C, and stirring was continued for 10 minutes after the dropwise addition was completed to obtain a composite solution. S2. The composite solution was subjected to spray drying (inlet temperature 170°C, outlet temperature 85°C), and a microspherical powder was collected to obtain a circulating water treatment composition.

[0047] Testing and evaluation The circulating water treatment compositions obtained in different examples and comparative examples were subjected to performance testing. The corrosion inhibition performance was tested in accordance with GB / T18175-2014 “Determination of Inhibition Performance of Water Treatment Agent by Rotating Hanging Piece Method”, wherein the pre-film conditions were 50 mg / L of the agent, room temperature, 24 h, and the running conditions were 25 mg / L of the agent, 45±1°C, 72 h. The test piece was 20# carbon steel. The scale inhibition performance was tested in accordance with GB / T16632-2019 “Determination of Scale Inhibition Performance of Water Treatment Agent by Calcium Carbonate Deposition Method”, wherein the agent concentration was 25 mg / L. The results are shown in Table 1.

[0048] Table 1. Test results

[0049] The above data prove that the scheme of the present application has low corrosion rate and high scale inhibition rate; Comparative Example 1 lacks inorganic corrosion inhibitor, and the corrosion inhibition performance decreases sharply, proving that molybdate / silicate is crucial for forming a firm passivation protective film; Comparative Example 2 has failed corrosion inhibition performance, and the product has poor physical state; Comparative Example 3 lacks plant polyphenol tannic acid, and the scale inhibition performance decreases significantly, and the corrosion inhibition performance is not as good as that of the ternary system.

[0050] The above merely provides the preferred embodiment of the present application, and the protection scope of the present application is not limited thereto. Any modification or replacement within the technical range disclosed by the present application should be covered within the protection scope of the present application.

Claims

1. A composition for treating circulating water, characterized by comprising: The composition comprises the following components in parts by mass: 5-10 parts of quaternary ammonium chitosan, 5-10 parts of anionic corrosion inhibitor, 1-1.5 parts of plant polyphenol.

2. The composition for treating circulating water according to claim 1, wherein The plant polyphenol is tannic acid.

3. The composition for treating circulating water according to claim 1, wherein The anionic corrosion inhibitor comprises molybdate and / or silicate.

4. The composition for treating circulating water according to claim 3, wherein The molybdate is sodium molybdate, and the silicate is sodium silicate.

5. A process for the preparation of a composition for the treatment of circulating water as claimed in any one of claims 1 to 4, characterized in that, The method comprises the following steps: Under stirring, an aqueous solution of the anionic corrosion inhibitor is added dropwise into a dilute acid solution of the quaternary ammonium chitosan, and after uniform mixing, an aqueous solution of the plant polyphenol is added to perform a self-assembly reaction to obtain a self-assembly composite solution; The self-assembly composite solution is subjected to spray drying to obtain the composition for treating circulating water.

6. The production method according to claim 5, wherein The rotation speed of the stirring is 8000-10000 rpm.

7. The preparation method according to claim 5, characterized in that, The inlet temperature of the spray drying is 160-180℃, and the outlet temperature is 80-90℃.

8. The preparation method according to claim 5, characterized in that, The temperature of the self-assembly reaction is 30-60℃.

9. Use of the composition for treating circulating water according to any one of claims 1-4 as a metal pre-film agent.

10. A method of treating circulating water, characterized by, The method comprises adding the composition for treating circulating water according to any one of claims 1-4 into circulating water to make the concentration of the composition in the circulating water 20-100 mg / L.

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