Composite functional oxygen scavenging resin and preparation method thereof

Abstract

The application discloses a kind of composite functional oxygen removal resin and preparation method thereof, belong to ion exchange resin technical field, crosslinking polystyrene chloromethylation ball is generated oxygen removal resin by post-crosslinking reaction, amination reaction, functional group modification, oxygen removal resin production process is by post-crosslinking reaction: dry chlorine ball swelling, catalyst catalyzes post-crosslinking, cleaning;Amination reaction: trimethylamine quaternization, cleaning;Functional group modification: reduction group load modification, washing and other processes are composed of.This application provides a kind of preparation method of composite functional oxygen removal resin, the oxygen removal resin prepared has good oxygen removal and regeneration performance, can be applied in boiler make-up water oxygen removal technology, solve the deficiencies of various oxygen removal technologies in the prior art, process is tedious, and the problems of poor oxygen removal performance and low oxygen removal capacity of commercially available oxygen removal resin, can be used for the treatment of dissolved oxygen in water in nuclear industry, electric power, petrochemical industry, metallurgy, biological medicine and other industries.

Description

Technical Field

[0001] This invention relates to the field of ion exchange resin technology, and more specifically to a composite functional oxygen-removing resin and its preparation method. Background Technology

[0002] Currently, softened water and demineralized water are used as boiler feedwater in my country's industrial boilers, leading to significant dissolved oxygen corrosion problems. Because oxygen corrosion is a slow process, some enterprises do not prioritize deoxygenation. Furthermore, due to a lack of effective deoxygenation technology, 50% of my country's industrial boilers are not equipped with deaerators. This results in a one-third reduction in the average lifespan of industrial boilers, causing substantial economic losses to enterprises and the nation. Traditional deoxygenation technologies used domestically include thermal deoxygenation, desorption deoxygenation, sponge iron deoxygenation (filtration deoxygenation), vacuum deoxygenation, chemical dosing deoxygenation, and membrane separation deoxygenation. These technologies all have limitations; some are energy-intensive, and others introduce harmful impurities into the water after deoxygenation, causing secondary corrosion. This makes it difficult to widely adopt traditional deoxygenation methods for industrial boilers.

[0003] Deoxygenation technology is based on chemical and physicochemical principles. For industrial boiler feedwater deoxygenation, aside from special cases where thermal deoxygenation (power plant deoxygenation) and vacuum deoxygenation (seawater deoxygenation) are retained, chemical deoxygenation technology primarily uses redox resins, while physicochemical deoxygenation technology mainly uses membrane separation. Chemical deoxygenation transforms free oxygen molecules into metal oxides or non-metal oxides. Oxygen reacts with metal elements to form metal oxides, such as dissolved oxygen in water reacting with sponge iron to form ferrous hydroxide and ferric hydroxide. Dissolved oxygen reacts with non-metal elements to form non-metal oxides, such as reacting with carbon to form carbon dioxide, and reacting with low-valence sulfides to form high-valence sulfides, such as dissolved oxygen reacting with sodium sulfite to form sodium sulfate. Dissolved oxygen reacts with elemental hydrogen to form water. Among these chemical elements, hydrogen is the most ideal, as the oxidation product is water, and no byproducts are produced during the reaction. Therefore, researchers in this field are dedicated to studying redox resin deoxygenation.

[0004] The key to redox resin deoxygenation technology lies in synthesizing a redox resin suitable for industrial applications, capable of providing a large number of reducing groups, such as inexpensive active hydrogen, organic hydrogen functional groups, or inorganic functional groups. If prepared using appropriate methods, the rapid reaction between oxygen in the water and the hydrogen or other reducing groups loaded on the deoxygenation resin can be enhanced, thereby removing more dissolved oxygen from the water and ensuring that the dissolved oxygen level in the effluent reaches the ppb level. Therefore, increasing the specific surface area of ​​the resin to accelerate the redox reaction, and providing more hydrogen or reducing groups, can promote a more thorough redox reaction, significantly improving deoxygenation efficiency, ensuring water quality while reducing operating costs, and saving energy.

[0005] The reducing agent loaded on the resin can react with dissolved oxygen in water in the form of triplet diradical oxygen [·OO·], reducing dissolved oxygen in water to below 50 μg / L. The reaction formula is as follows:

[0006] R-SO3+·OO·→R-SO4+SO4 2-

[0007] HO-R-OH+·OO·→R-OH+H2O Summary of the Invention

[0008] This invention provides a method for preparing a composite functional deoxygenating resin. The prepared deoxygenating resin has good deoxygenation and regeneration performance and can be applied to boiler feedwater deoxygenation technology. It solves the shortcomings of various existing deoxygenation technologies, such as cumbersome processes, poor deoxygenation performance and low deoxygenation capacity of commercially available deoxygenating resins. It can be used for the treatment of dissolved oxygen in water in industries such as nuclear industry, power, petrochemical, metallurgy, and biomedicine.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A composite functional oxygen-removing resin, characterized in that it comprises the following raw materials:

[0011]

[0012]

[0013] The cross-linked polystyrene chloromethylated spheres have a cross-linking degree of 6.5% and a chlorine content of 17.5%.

[0014] Another objective of this invention is to provide a method for preparing a composite functional oxygen-removing resin, comprising the following steps:

[0015] (1) Weighing

[0016] Weigh out each raw material in the above-mentioned composite functional oxygen-removing resin and set aside.

[0017] (2) Post-crosslinking reaction of crosslinked polystyrene chloromethylated spheres

[0018] Cross-linked polystyrene chloromethylated spheres and dichloroethane were added sequentially to the reactor. The mixture expanded under stirring. After stirring was stopped, anhydrous ferric chloride was added. After stabilization, the temperature was raised to react. Then, the mixture was distilled, washed with 30wt% concentrated hydrochloric acid, washed with water, and filtered to obtain the post-cross-linked resin for later use.

[0019] (3) Amination reaction

[0020] The post-crosslinking resin, 30wt% sodium hydroxide aqueous solution, and water were added to the reactor in sequence. The pH was adjusted once, the temperature was raised and 30wt% trimethylamine aqueous solution was added. After reacting for a period of time, the temperature was lowered and the material was discharged. 30wt% hydrochloric acid was added dropwise to adjust the pH a second time. After stabilization, the material was discharged and cooled to room temperature. The obtained resin was diluted, filtered, and washed to obtain amination resin balls for later use.

[0021] (4) Functional group modification

[0022] The amination resin balls were pretreated with acid and alkali and cleaned. The resin was then loaded with reducing groups such as 12wt% hydroquinone aqueous solution and 5wt% sodium sulfite aqueous solution. After washing, the deoxygenated resin was obtained.

[0023] Furthermore, the stabilization time in step (2) is 0.5 to 1 hour; the heating reaction is carried out at 60-85°C for 2-6 hours.

[0024] Furthermore, in step (3), the first pH adjustment is to adjust the pH to 10-12; the heating is to raise the temperature to 50-70℃; the reaction time cooling is to react for 8-12 hours and then cool down to 40℃; the second pH adjustment is to adjust the pH to 2; and the stabilization time is 2 hours.

[0025] Further, step (4) specifically includes the following steps: The amination resin balls are pretreated twice with 5wt% sulfuric acid solution, deionized water, 8wt% sodium hydroxide aqueous solution, and deionized water. They are then washed three times with 80 parts of hot water at 60℃ for 2-3 hours each time. After dynamic treatment with 8wt% sodium hydroxide aqueous solution to form the OH form, the balls are washed with deionized water until the effluent conductivity is ≤5μs / cm. Then, they are sequentially subjected to 5wt% sodium sulfite aqueous solution, deionized water, 12wt% hydroquinone aqueous solution, and deionized water for loading modification with reducing groups. Finally, the balls are washed with deionized water until the effluent conductivity is ≤5μs / cm to obtain the deoxygenated resin.

[0026] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. Increase the redox reaction rate by increasing the specific surface area of ​​the resin;

[0028] 2. Increasing the loading of more reducing groups can promote a more thorough redox reaction, thereby significantly improving the deoxygenation efficiency and solving the problem of increasing the working exchange capacity;

[0029] 3. By increasing the specific surface area and loading more reducing groups, the problem of lower dissolved oxygen removal in the effluent quality is solved, meeting the lower dissolved oxygen requirements of special water quality.

[0030] 4. It has excellent deoxygenation and regeneration performance, ensuring water quality while reducing operating costs and saving energy. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the synthesis process of the composite functional oxygen-removing resin of the present invention.

[0033] Figure 2 This is a schematic diagram of the synthesis reaction of the composite functional oxygen-removing resin of the present invention.

[0034] Figure 3 This is a schematic diagram of the synthetic structure of the composite functional oxygen-removing resin of the present invention. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] The following composite functional oxygen-removing resins were tested according to GB / T 11992-2008 "Determination of exchange capacity of chloride-type strong basic anion exchange resins".

[0037] Example 1

[0038] (1) Post-crosslinking reaction of crosslinked polystyrene chloromethylated spheres

[0039] Weigh out the required amounts according to weight, add 10 parts of cross-linked polystyrene chloromethylated balls and 50 parts of dichloroethane to the reactor in sequence, expand under stirring, stop stirring, add 1.5 parts of anhydrous ferric chloride, stabilize for 0.5 h, raise the temperature to 85℃, react for 6 h, raise the temperature to 100℃ and distill to recover dichloroethane for 12 h, wash the obtained filter balls with 90 parts of 30% hydrochloric acid aqueous solution and 300 parts of deionized water respectively to obtain post-cross-linked resin balls;

[0040] (2) Amination reaction

[0041] Weigh out the cross-linked resin balls obtained in (1) and 25 parts of sodium hydroxide aqueous solution with a mass fraction of 30% in sequence into the reactor, adjust the pH to 12, raise the temperature to 60°C, add 25 parts of trimethylamine with a mass fraction of 30%, react for 10 h, cool down to 40°C, drain the mother liquor, wash with 300 parts of deionized water, add 10 parts of hydrochloric acid with a mass fraction of 30% to adjust the pH to 2, stabilize for 2 h, discharge the material, cool to room temperature, wash the obtained filter balls with 300 parts of deionized water to obtain amination resin balls;

[0042] (3) Functional group modification

[0043] Weigh out the required amounts according to weight, and place the amination resin balls in a solution containing 5% sulfuric acid for 4 hours, 200 parts of deionized water for 5 hours, 40 parts of 8% sodium hydroxide solution for 4 hours, and 400 parts of deionized water for 10 hours. Repeat this pretreatment twice. Wash with 80 parts of 60℃ hot water three times, each time for 2-3 hours. Dynamically treat with 420 parts of 8% sodium hydroxide solution to form the OH form, and wash with 450 parts of deionized water until the effluent conductivity is ≤5μs / cm. The resin is then sequentially treated with 90 parts of 5% sodium sulfite solution, washed with 500 parts of deionized water, treated with 50 parts of 12% hydroquinone solution, and washed with 500 parts of deionized water to complete the loading modification of the reducing groups. Finally, wash with 500 parts of deionized water until the effluent conductivity is ≤5μs / cm to obtain the deoxygenating resin.

[0044] The cross-linked polystyrene chloromethylated spheres have a cross-linking degree of 6.5% and a chlorine content of 17.5%.

[0045] The composite functional oxygen-scavenging resin obtained above has an exchange capacity of 2.55 mmol / g for the chloride form and a specific surface area of ​​593 m² for the sulfite form. 2 / g, with an influent oxygen content of 8mg / L, an effluent dissolved oxygen content ≤0.05mg / L, and a dissolved oxygen saturation adsorption capacity of 8630mg / L.

[0046] Example 2

[0047] (1) Post-crosslinking reaction of crosslinked polystyrene chloromethylated spheres

[0048] Weigh out the required amounts according to weight, add 15 parts of cross-linked polystyrene chloromethylated balls and 40 parts of dichloroethane to the reactor in sequence, expand under stirring, stop stirring, add 1.5 parts of anhydrous ferric chloride, stabilize for 0.5 h, raise the temperature to 70℃, react for 4 h, raise the temperature to 100℃ and distill to recover dichloroethane for 12 h, wash the obtained filter balls with 100 parts of 30% hydrochloric acid aqueous solution and 400 parts of deionized water respectively to obtain post-cross-linked resin balls;

[0049] (2) Amination reaction

[0050] Weigh out the cross-linked resin balls obtained in (1) and 25 parts of sodium hydroxide aqueous solution with a mass fraction of 30% in sequence into the reactor, adjust the pH to 12, raise the temperature to 60°C, add 25 parts of trimethylamine with a mass fraction of 30%, react for 10 h, cool down to 40°C, drain the mother liquor, wash with 300 parts of deionized water, add 10 parts of hydrochloric acid aqueous solution with a mass fraction of 30% to adjust the pH to 2, stabilize for 2 h, discharge the material, cool to room temperature, wash the obtained filter balls with 300 parts of deionized water to obtain amination resin balls;

[0051] (3) Functional group modification

[0052] Weigh out the required amounts according to weight. Place the amination resin balls in a solution containing 40 parts by weight of 5% sulfuric acid for 4 hours, then in 200 parts by weight of deionized water for 5 hours, then in 40 parts by weight of 8% sodium hydroxide solution for 4 hours, and finally in 400 parts by weight of deionized water for 10 hours. Repeat this pretreatment process twice. Wash three times with 80 parts of hot water at 60℃, each time for 2-3 hours. Dynamically treat with 400 parts by weight of 8% sodium hydroxide solution to form the OH form, and then wash with 400 parts by weight of deionized water until the effluent conductivity is ≤5 μS / cm. The resin is then sequentially treated with 80 parts by weight of 5% sodium sulfite solution, washed with 400 parts by weight of deionized water, treated with 40 parts by weight of 12% hydroquinone solution, and washed with 400 parts by weight of deionized water. The reducing groups are then loaded and modified, and the resin is washed with 400 parts by weight of deionized water until the effluent conductivity is ≤5 μS / cm, yielding the deoxygenating resin.

[0053] The cross-linked polystyrene chloromethylated spheres have a cross-linking degree of 6.5% and a chlorine content of 17.5%.

[0054] The composite functional oxygen-scavenging resin obtained above has an exchange capacity of 3.05 mmol / g for the chloride form and a specific surface area of ​​453 m² for the sulfite form. 2 / g, with an influent oxygen content of 8mg / L, an effluent dissolved oxygen content ≤0.05mg / L, and a dissolved oxygen saturation adsorption capacity of 8200mg / L.

[0055] Example 3

[0056] (1) Post-crosslinking reaction of crosslinked polystyrene chloromethylated spheres

[0057] Weigh out the required amounts according to weight, add 10 parts of cross-linked polystyrene chloromethylated balls and 40 parts of dichloroethane to the reactor in sequence, expand under stirring, stop stirring, add 2 parts of anhydrous ferric chloride, stabilize for 0.5 h, raise the temperature to 62℃, react for 2 h, raise the temperature to 100℃ and distill to recover dichloroethane for 12 h, wash the obtained filter balls with 90 parts of 30% hydrochloric acid aqueous solution and 300 parts of deionized water respectively to obtain post-cross-linked resin balls;

[0058] (2) Amination reaction

[0059] Weigh out the cross-linked resin balls obtained in (1) and 30 parts of sodium hydroxide aqueous solution with a mass fraction of 30% in sequence into the reactor, adjust the pH to 12, raise the temperature to 60°C, add 30 parts of trimethylamine with a mass fraction of 30%, react for 10 hours, cool down to 40°C, drain the mother liquor, wash with 300 parts of deionized water, add 10 parts of hydrochloric acid with a mass fraction of 30% to adjust the pH to 2, stabilize for 2 hours, discharge the material, cool to room temperature, wash the obtained filter balls with 300 parts of deionized water to obtain amination resin balls;

[0060] (3) Functional group modification

[0061] Weigh out the required amounts according to weight. Place the amination resin balls in a solution containing 40 parts by weight of 5% sulfuric acid for 4 hours, then in 200 parts by weight of deionized water for 5 hours, then in 40 parts by weight of 8% sodium hydroxide solution for 4 hours, and finally in 400 parts by weight of deionized water for 10 hours. Repeat this pretreatment process twice. Wash three times with 80 parts of hot water at 60℃, each time for 2-3 hours. Dynamically treat with 400 parts by weight of 8% sodium hydroxide solution to form the OH form, and then wash with 400 parts by weight of deionized water until the effluent conductivity is ≤5 μS / cm. The resin is then sequentially treated with 80 parts by weight of 5% sodium sulfite solution, washed with 400 parts by weight of deionized water, treated with 40 parts by weight of 12% hydroquinone solution, and washed with 400 parts by weight of deionized water. The reducing groups are then loaded and modified, and the resin is washed with 400 parts by weight of deionized water until the effluent conductivity is ≤5 μS / cm, yielding the deoxygenating resin.

[0062] The cross-linked polystyrene chloromethylated spheres have a cross-linking degree of 6.5% and a chlorine content of 17.5%.

[0063] The composite functional oxygen-scavenging resin obtained above has an exchange capacity of 3.32 mmol / g for the chloride form and a specific surface area of ​​393 m² for the sulfite form. 2 / g, with an influent oxygen content of 8mg / L, an effluent dissolved oxygen content ≤0.05mg / L, and a dissolved oxygen saturation adsorption capacity of 8638mg / L.

[0064] Example 4

[0065] (1) Post-crosslinking reaction of crosslinked polystyrene chloromethylated spheres

[0066] Weigh out the required amounts according to weight, add 12 parts of cross-linked polystyrene chloromethylated balls and 40 parts of dichloroethane to the reactor in sequence, expand under stirring, stop stirring, add 1.5 parts of anhydrous ferric chloride, stabilize for 0.5 h, raise the temperature to 62℃, react for 2 h, raise the temperature to 100℃ and distill to recover dichloroethane for 12 h, wash the obtained filter balls with 95 parts of 30% hydrochloric acid aqueous solution and 300 parts of deionized water respectively to obtain post-cross-linked resin balls;

[0067] (2) Amination reaction

[0068] Weigh out the cross-linked resin balls obtained in (1) and 28 parts of sodium hydroxide aqueous solution with a mass fraction of 30% in sequence into the reactor, adjust the pH to 12, raise the temperature to 60°C, add 28 parts of trimethylamine with a mass fraction of 30%, react for 10 h, cool down to 40°C, drain the mother liquor, wash with 300 parts of deionized water, add 10 parts of hydrochloric acid with a mass fraction of 30% to adjust the pH to 2, stabilize for 2 h, discharge the material, cool to room temperature, wash the obtained filter balls with 300 parts of deionized water to obtain amination resin balls;

[0069] (3) Functional group modification

[0070] Weigh out the required amounts according to weight. Place the amination resin balls in a solution containing 45 parts by weight of 5% sulfuric acid for 4 hours, then in 200 parts by weight of deionized water for 5 hours, then in 40 parts by weight of 8% sodium hydroxide solution for 4 hours, and finally in 400 parts by weight of deionized water for 10 hours. Repeat this pretreatment twice. Wash three times with 80 parts of hot water at 60℃, each time for 2-3 hours. Dynamically treat with 400 parts by weight of 8% sodium hydroxide solution to form the OH form, and wash with 400 parts by weight of deionized water until the effluent conductivity is ≤5 μS / cm. The resin is then sequentially treated with 100 parts by weight of 5% sodium sulfite solution, washed with 400 parts by weight of deionized water, treated with 120 parts by weight of 12% hydroquinone solution, and washed with 400 parts by weight of deionized water. The reducing groups are then loaded and modified, and the resin is washed with 400 parts by weight of deionized water until the effluent conductivity is ≤5 μS / cm, yielding the deoxygenating resin.

[0071] The cross-linked polystyrene chloromethylated spheres have a cross-linking degree of 6.5% and a chlorine content of 17.5%.

[0072] The composite functional oxygen-scavenging resin obtained above has an exchange capacity of 3.05 mmol / g for the chloride form and a specific surface area of ​​401 m² for the sulfite form. 2 / g, with an influent oxygen content of 8mg / L, an effluent dissolved oxygen content ≤0.05mg / L, and a dissolved oxygen saturation adsorption capacity of 8320mg / L.

[0073] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0074] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a composite functional oxygen-removing resin, characterized in that, The composite functional oxygen-removing resin comprises the following raw materials in parts by weight: 10-15 parts of cross-linked polystyrene chloromethylated spheres; 40-50 parts of dichloroethane; 1.5-2 parts of anhydrous ferric chloride; 25-30 parts of 30wt% trimethylamine aqueous solution; 5-30 parts of 30wt% sodium hydroxide aqueous solution; 100-120 parts of 30wt% hydrochloric acid aqueous solution; 40-500 parts of 8wt% sodium hydroxide aqueous solution; 40-50 parts of 12wt% hydroquinone aqueous solution; 80-90 parts of 5wt% sodium sulfite aqueous solution; 40-45 parts of 5wt% sulfuric acid solution; 2000-3000 parts of deionized water; The cross-linked polystyrene chloromethylated spheres have a cross-linking degree of 6.5% and a chlorine content of 17.5%. The preparation method includes the following steps: (1) Weighing Weigh each raw material in the composite functional oxygen-removing resin and set aside for later use; (2) Post-crosslinking reaction of crosslinked polystyrene chloromethylated spheres Cross-linked polystyrene chloromethylated spheres and dichloroethane were added sequentially to the reactor. The mixture expanded under stirring. After stirring was stopped, anhydrous ferric chloride was added. After stabilization, the temperature was raised to react. Then, the mixture was distilled, washed with 30wt% hydrochloric acid aqueous solution, washed with water, and filtered to obtain the post-cross-linked resin for later use. (3) Amination reaction Post-crosslinking resin, 30wt% sodium hydroxide aqueous solution, and deionized water were added to the reactor in sequence. The pH was adjusted once, the temperature was raised and 30wt% trimethylamine aqueous solution was added. After reacting for a period of time, the temperature was lowered and the material was discharged. 30wt% hydrochloric acid aqueous solution was added dropwise to adjust the pH a second time. After stabilization, the material was discharged and cooled to room temperature. The obtained resin was washed to obtain amination resin balls for later use. (4) Functional group modification The amination resin balls were pretreated with acid and alkali and cleaned. The resin was then loaded with reducing groups by adding 12wt% hydroquinone aqueous solution and 5wt% sodium sulfite aqueous solution. After washing, the deoxygenated resin was obtained.

2. The method for preparing a composite functional oxygen-removing resin according to claim 1, characterized in that, The stabilization time in step (2) is 0.5~1h; the heating reaction is carried out at 60-85℃ for 2-6h.

3. The method for preparing a composite functional oxygen-removing resin according to claim 1, characterized in that, In step (3), the first pH adjustment is to adjust the pH to 10-12; the heating is to raise the temperature to 50-70℃; the cooling after a period of reaction is to react for 8-12 hours and then cool down to 40℃; the second pH adjustment is to adjust the pH to 2; and the stabilization time is 2 hours.

4. The method for preparing a composite functional oxygen-removing resin according to claim 1, characterized in that, Step (4) specifically includes the following steps: the amination resin balls are treated with 5wt% sulfuric acid solution, washed with deionized water, treated with 8wt% sodium hydroxide aqueous solution, and washed with deionized water. This pretreatment is repeated twice. 80 parts are washed with 60℃ deionized water three times, each time for 2-3 hours. The balls are dynamically treated with 8wt% sodium hydroxide aqueous solution to form the OH form. Then, they are washed with deionized water until the effluent conductivity is ≤5μs / cm. Then, they are treated with 5wt% sodium sulfite aqueous solution, washed with deionized water, treated with 12wt% hydroquinone aqueous solution, and washed with deionized water. The reducing groups are loaded and modified. Finally, the balls are washed with deionized water until the effluent conductivity is ≤5μs / cm to obtain the deoxygenated resin.

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