Water body softening material and method of making same

Abstract

The present application relates to power plant water treatment technical field, especially to a kind of water softening material and preparation method thereof, including bamboo fiber, chitosan, sodium alginate and humic acid sodium.The surface of bamboo fiber contains a large number of hydroxyl groups, the surface of sodium alginate contains a large number of carboxyl and hydroxyl groups, and the surface of chitosan contains a large number of carboxyl, hydroxyl, phenolic hydroxyl and amino groups, therefore, esterification reaction can occur between sodium alginate and bamboo fiber to convert the hydroxyl groups on the surface of bamboo fiber into ester groups, while humic acid sodium itself can be ion adsorbed and combined with the amino groups on the surface of chitosan, and at the same time, the ester groups on the surface of bamboo fiber and the amide reaction of chitosan can fully combine bamboo fiber, sodium alginate, chitosan and humic acid sodium to further improve the strength and stability of bamboo fiber, and at the same time, the adsorption, exchange, complexation and chelation capabilities of each raw material are maximally retained to effectively adsorb and reduce metal ions, ammonia nitrogen and nitrite in water.

Description

Technical Field

[0001] This invention relates to the field of power plant water treatment technology, and in particular to a water softening material and its preparation method. Background Technology

[0002] Boilers are indispensable equipment in thermal power generation. During the operation of hot water boilers, feedwater containing impurities (mainly hardness components) enters the boiler. Due to the high concentration of scale-forming components such as calcium and magnesium in the water, continuous evaporation and concentration lead to saturation, causing solid deposits to precipitate. These deposits firmly adhere to the heating surfaces, forming scale. When the calcium, magnesium, and iron scale components entering the boiler kettle adhere to the heat transfer surfaces under high heat loads, they cause heat transfer obstruction. This obstruction can lead to overheating, causing steel expansion, bending, and cracking, as well as reduced thermal efficiency. It can also cause boiler steel plates and pipes to burn out due to overheating, resulting in significant fuel waste, reduced boiler output, increased boiler maintenance, and safety hazards. Therefore, scale is often referred to as the "source of all harm" in boilers.

[0003] Descaling boilers is extremely difficult and generates wastewater. During descaling, the boiler cannot operate normally, severely impacting power generation. Therefore, the most suitable method for boiler descaling is prevention, namely, pre-treating the boiler water with softening.

[0004] Boiler water softeners can be divided into two categories: chemical softeners and ion exchange softeners. Chemical softeners primarily work by adding chemicals, such as phosphates and carbonates, which react with calcium and magnesium ions in the water to form soluble compounds, thus softening the water. This method is simple to operate and relatively inexpensive, but it may introduce new chemical substances that can negatively impact water quality. Ion exchange softeners, on the other hand, use ion exchange resins to treat the water. Exchangeable ions (such as sodium ions) in the resin exchange with calcium and magnesium ions in the water, thereby removing hardness. This method provides stable softening and has less impact on water quality, but it is more expensive and requires regular resin replacement.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a water softening material and its preparation method. The water softening material of this invention has a high capture capacity for calcium, magnesium and other ions, and can directly soften hard water during the flow process, thus having the advantages of efficient and rapid water softening.

[0007] In a first aspect, the present invention provides a water softening material, comprising the following raw materials in parts by weight:

[0008] Bamboo fiber 10-50 parts, chitosan 2-10 parts, sodium alginate 1-5 parts and sodium humate 1-5 parts.

[0009] The water softening material of this invention comprises bamboo fiber, chitosan, sodium alginate, and sodium humate. The surface of bamboo fiber contains a large number of hydroxyl groups, the surface of sodium alginate contains a large number of carboxyl and hydroxyl groups, the surface of chitosan contains a large number of hydroxyl and amino groups, and sodium humate contains a large number of carboxyl and phenolic hydroxyl groups. Therefore, using bamboo fiber as a framework, sodium alginate and bamboo fiber can undergo esterification to convert the hydroxyl groups on the surface of bamboo fiber into ester groups, significantly improving the wet strength of bamboo fiber. Humic acid itself can adsorb and bind with the amino ions on the surface of chitosan, dissolving impurities. Simultaneously, the ester groups on the surface of modified bamboo fiber react with the remaining amino groups of chitosan through amidation, fully combining bamboo fiber, sodium alginate, chitosan, and humic acid to further improve the strength and stability of bamboo fiber. At the same time, it maximizes the retention of the adsorption, exchange, complexation, and chelation capabilities of each raw material to effectively adsorb and reduce metal ions, ammonia nitrogen, and nitrite in the water.

[0010] The water softening material of this invention also includes a catalyst. Bamboo fibers and sodium alginate undergo an esterification reaction under the action of the catalyst, which significantly improves reaction efficiency, saves energy required for the reaction, and thus enhances the wet strength of the bamboo fibers, making them more suitable for use in aquatic environments. Specifically, the amount of catalyst used is 0.5-2 parts, and the catalyst includes either disodium hydrogen phosphate or sodium dihydrogen phosphate. Disodium hydrogen phosphate and sodium dihydrogen phosphate not only serve as catalysts for the reaction between the hydroxyl groups on the surface of bamboo fibers and the carboxyl groups on the surface of sodium alginate, but they are also commonly used water softeners themselves.

[0011] As a preferred embodiment of this technical solution, the water softener of the present invention further includes 0.5-2 parts of an acidic solution, wherein the acidic solution includes any one of dilute acetic acid, dilute hydrochloric acid, dilute sulfuric acid and dilute nitric acid, preferably white vinegar, which is environmentally friendly, inexpensive, readily available and easy to store.

[0012] The acidic solution is mainly used to promote the dissolution of chitosan in order to maximize the film-forming properties of chitosan and allow it to adhere to the surface of bamboo fiber, thereby improving the strength and stability of bamboo fiber. The phenolic hydroxyl groups in sodium humate serve to resist oxidation conditions in application scenarios such as light, thus extending the service life of the material.

[0013] As a preferred embodiment of this technical solution, the chitosan is preferably acid-soluble chitosan, which is weakly alkaline and has a higher purity (i.e., higher amino content) than water-soluble chitosan.

[0014] Secondly, the present invention also provides a method for preparing the above-mentioned water softening material, which should also fall within the scope of protection of the present invention, specifically including the following steps:

[0015] S1. Add the catalyst to the aqueous solution of sodium alginate, stir and dissolve it thoroughly, then add bamboo fiber, and stir and heat in sequence to obtain solution A containing bamboo fiber.

[0016] S2. Add sodium humate to the aqueous solution of chitosan, stir and mix thoroughly to obtain solution B;

[0017] S3. Mix solution A containing bamboo fiber with solution B, place them in a high-pressure reactor, and heat-dry and expand them to obtain a water softening material.

[0018] There is no restriction on the order of steps S1 and S2.

[0019] In the preparation method of this invention, firstly, a sodium alginate solution is prepared. Using bamboo fiber as a framework, under the catalysis of disodium hydrogen phosphate or sodium dihydrogen phosphate, the hydroxyl groups on the surface of bamboo fiber undergo an esterification reaction with the carboxyl groups on the surface of sodium alginate to improve the wet strength of bamboo fiber, thus obtaining solution A containing bamboo fiber. Simultaneously, an aqueous solution of acid-soluble chitosan is prepared, and then sodium humate is added to the acid-soluble chitosan aqueous solution to obtain solution B. Sodium humate itself can adsorb and bind with the amino ions in acid-soluble chitosan. Therefore, acid-soluble chitosan can retain and coat many active groups such as phenolic hydroxyl groups, quinone groups, and carboxyl groups in sodium humate, thereby retaining humic acid. The sodium adsorption, exchange, complexation, and chelation capabilities are used to effectively enhance the water softening material's ability to adsorb and reduce metal ions, ammonia nitrogen, and nitrite in the water. Finally, solution A containing bamboo fiber is mixed with solution B and placed in a high-pressure reactor for hot drying and expansion. In the first step, the ester groups on the surface of the modified bamboo fiber and the amino groups on the surface of the acid-soluble chitosan can undergo an amidation reaction, thereby firmly binding the bamboo fiber, sodium alginate, chitosan, and sodium humate through two organic reactions and a double-layer membrane. During the high-temperature hot drying and expansion process, the film-forming properties of sodium alginate and chitosan are fully utilized, resulting in a final modified bamboo fiber structure with higher strength and more stable performance.

[0020] As a preferred embodiment of this technical solution, in step S1, after adding an appropriate amount of bamboo fiber, the mixture is first stirred thoroughly to ensure that the bamboo fiber is fully dispersed in the sodium alginate solution. Then, a heating treatment is performed to promote the esterification reaction between the carboxyl groups in the sodium alginate and the hydroxyl groups on the surface of the bamboo fiber. Specifically, during the heating treatment, the temperature can be controlled at 80-120℃ and the time is 3-7 hours, preferably 5 hours at 80-120℃.

[0021] In a preferred embodiment of this technical solution, in step S2, after mixing food-grade acid-soluble chitosan with water, an appropriate amount of acidic solution is added and the mixture is stirred thoroughly for 4-8 hours to promote the dissolution of acid-soluble chitosan and obtain an aqueous solution of acid-soluble chitosan.

[0022] In a preferred embodiment of this technical solution, in step S2, after the acid-soluble chitosan is fully dissolved, sodium humate is added to the aqueous solution of the acid-soluble chitosan, and the pH is adjusted to 6.5-7.5 to obtain solution B.

[0023] In a preferred embodiment of this technical solution, in step S3, solution A containing bamboo fiber is mixed with solution B and placed into a stainless steel high-pressure reactor for hot drying and puffing. Specifically, during the hot drying and puffing process, the temperature is controlled at 160-200℃ and the time is 8-16 hours. Water vapor needs to be discharged in time during the process to obtain the water softening material.

[0024] During the high-temperature baking and puffing process, sodium alginate and acid-soluble chitosan can fully exert their film-forming properties. Therefore, under the action of the two-step organic reaction of esterification and amidation, the sodium alginate and acid-soluble chitosan double-layer film can be stably combined on the surface of bamboo fiber. After the bamboo fiber is modified by the double-layer protective film, its strength in the wet environment is significantly improved. It can be folded and deformed at will according to the application scenario. At the same time, the prepared water softening material has a three-dimensional fishing net structure and its surface is densely covered with multiple active groups, which has a high capture capacity for metal ions such as calcium and magnesium, and can effectively adsorb and reduce ammonia nitrogen and nitrite in water.

[0025] As a preferred embodiment of this technical solution, the water softening material can be recycled after being soaked and stirred in dilute acid, subjected to ultrasonic vibration, or washed. It features low treatment cost, easy operation, rapid effect, complete environmental friendliness, and unrestricted application.

[0026] The water softening material of the present invention has at least the following beneficial effects:

[0027] 1. The water softening material of the present invention comprises bamboo fiber, chitosan, sodium alginate, and sodium humate. The surface of bamboo fiber contains a large number of hydroxyl groups, the surface of sodium alginate contains a large number of carboxyl and hydroxyl groups, the surface of chitosan contains a large number of amino and hydroxyl groups, and sodium humate contains phenolic hydroxyl and carboxyl groups. Therefore, the carboxyl groups on the surface of sodium alginate and the hydroxyl groups on the surface of bamboo fiber can undergo an esterification reaction to convert the hydroxyl groups on the surface of bamboo fiber into ester groups. Sodium humate itself can adsorb and bind with the amino ions on the surface of chitosan. Therefore, during the mixing process of sodium humate and chitosan... Chitosan can firmly coat sodium humate, thus preserving the active groups such as phenolic hydroxyl groups, quinone groups, and carboxyl groups within the sodium humate to the greatest extent. At the same time, the surface of bamboo fiber modified with sodium alginate is rich in ester groups. The amidation reaction between the ester groups and chitosan can fully combine bamboo fiber, sodium alginate, chitosan, and sodium humate to further improve the strength and stability of bamboo fiber. Meanwhile, it maximizes the adsorption, exchange, complexation, and chelation capabilities of each raw material to effectively adsorb and reduce metal ions, ammonia nitrogen, and nitrite in water.

[0028] 2. The water softening material of the present invention has high wet strength, a three-dimensional fishing net structure, and a surface rich in functional groups such as phenolic hydroxyl, quinone, carboxyl, and amide groups. The finished product is similar to a fishing net and has low resistance in water. It has a high capture capacity for calcium, magnesium and other ions and can directly soften hard water during the flow process. It has the advantages of efficient and rapid water softening.

[0029] 3. The water softening material of the present invention has low purification cost, low loss and low maintenance cost, the material can be folded and deformed at will, the application scenarios are not limited, and the process is green, environmentally friendly and pollution-free.

[0030] 4. The raw materials for the water softening material of this invention are all natural and renewable substances, and the quality requirements for the four raw materials are low, and the price is inexpensive.

[0031] 5. The water softening material of the present invention can be recycled after being soaked and stirred in dilute acid, subjected to ultrasonic vibration, or washed. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is an external image of the water softening material of the present invention;

[0034] Figure 2This is a schematic diagram of the water softening material of the present invention softening water. Detailed Implementation

[0035] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0038] Example 1

[0039] S1. Weigh and prepare a 3wt% sodium alginate aqueous solution, and add 1wt% sodium dihydrogen phosphate to the sodium alginate aqueous solution. After stirring and dissolving thoroughly, add 30wt% bamboo fiber. Stir for 3 hours and then heat at 100℃ for 5 hours to obtain solution A containing bamboo fiber.

[0040] S2. Weigh and prepare a 6wt% acid-soluble chitosan aqueous solution, add 3wt% sodium humate to it, stir thoroughly for 4-8 hours, adjust the pH of the solution to neutral, and obtain solution B;

[0041] S3. Mix solution A containing bamboo fiber with solution B, place them in a stainless steel high-pressure reactor, and heat-dry and expand them at 180°C for 12 hours. During the process, water vapor is discharged in time to obtain water softening material.

[0042] There is no restriction on the order of steps S1 and S2.

[0043] Example 2

[0044] S1. Weigh and prepare a 1 wt% sodium alginate aqueous solution, and add 0.5 wt% sodium dihydrogen phosphate to the sodium alginate aqueous solution. After stirring and dissolving thoroughly, add 10 wt% bamboo fiber. Stir for 3 hours and then heat at 80°C for 7 hours to obtain solution A containing bamboo fiber.

[0045] S2. Weigh and prepare a 2wt% acid-soluble chitosan aqueous solution, add 1wt% sodium humate to it, stir thoroughly for 4-8 hours, adjust the pH of the solution to neutral, and obtain solution B;

[0046] S3. Mix solution A containing bamboo fiber with solution B, place them in a stainless steel high-pressure reactor, and heat-dry and expand them at 160°C for 16 hours. During the process, water vapor is discharged in time to obtain water softening material.

[0047] There is no restriction on the order of steps S1 and S2.

[0048] Example 3

[0049] S1. Weigh and prepare a 5wt% sodium alginate aqueous solution, and add 2wt% sodium dihydrogen phosphate to the sodium alginate aqueous solution. After stirring and dissolving thoroughly, add 50wt% bamboo fiber. Stir for 3 hours and then heat at 120℃ for 3 hours to obtain solution A containing bamboo fiber.

[0050] S2. Weigh and prepare a 10wt% acid-soluble chitosan aqueous solution, add 5wt% sodium humate to it, stir thoroughly for 4-8 hours, adjust the pH of the solution to neutral, and obtain solution B.

[0051] S3. Mix solution A containing bamboo fiber with solution B, place them in a stainless steel high-pressure reactor, and heat-dry and expand them at 200℃ for 8 hours. During the process, water vapor is discharged in time to obtain water softening material.

[0052] There is no restriction on the order of steps S1 and S2.

[0053] Example 4

[0054] S1. Weigh and prepare a 2wt% sodium alginate aqueous solution, and add 1wt% sodium dihydrogen phosphate to the sodium alginate aqueous solution. After stirring and dissolving thoroughly, add 20wt% bamboo fiber. Stir for 3 hours and then heat at 90℃ for 6 hours to obtain solution A containing bamboo fiber.

[0055] S2. Weigh and prepare a 4wt% acid-soluble chitosan aqueous solution, add 2wt% sodium humate to it, stir thoroughly for 4-8 hours, adjust the pH of the solution to neutral, and obtain solution B;

[0056] S3. Mix solution A containing bamboo fiber with solution B, place them in a stainless steel high-pressure reactor, and heat-dry and expand them at 170°C for 14 hours. During the process, water vapor is discharged in time to obtain water softening material.

[0057] There is no restriction on the order of steps S1 and S2.

[0058] Example 5

[0059] S1. Weigh and prepare a 3wt% sodium alginate aqueous solution, and add 1.5wt% sodium dihydrogen phosphate to the sodium alginate aqueous solution. After stirring and dissolving thoroughly, add 25wt% bamboo fiber. Stir for 3 hours and then heat at 100℃ for 5 hours to obtain solution A containing bamboo fiber.

[0060] S2. Weigh and prepare a 4wt% acid-soluble chitosan aqueous solution, add 3wt% sodium humate to it, stir thoroughly for 4-8 hours, adjust the pH of the solution to neutral, and obtain solution B;

[0061] S3. Mix solution A containing bamboo fiber with solution B, place them in a stainless steel high-pressure reactor, and heat-dry and expand them at 180°C for 10 hours. During the process, water vapor is discharged in time to obtain water softening material.

[0062] There is no restriction on the order of steps S1 and S2.

[0063] Example 6

[0064] S1. Weigh and prepare a 4wt% sodium alginate aqueous solution, and add 2wt% sodium dihydrogen phosphate to the sodium alginate aqueous solution. After stirring and dissolving thoroughly, add 40wt% bamboo fiber. Stir for 3 hours and then heat at 110℃ for 4 hours to obtain solution A containing bamboo fiber.

[0065] S2. Weigh and prepare an 8wt% acid-soluble chitosan aqueous solution, add 4wt% sodium humate to it, stir thoroughly for 4-8 hours, adjust the pH of the solution to neutral, and obtain solution B;

[0066] S3. Mix solution A containing bamboo fiber with solution B, place them in a stainless steel high-pressure reactor, and heat-dry and expand them at 190°C for 9 hours. During the process, water vapor is discharged in time to obtain water softening material.

[0067] There is no restriction on the order of steps S1 and S2.

[0068] Compare with Example 1

[0069] The difference from Example 1 is that sepiolite fiber is used instead of bamboo fiber in Example 1;

[0070] The other steps and parameters are basically the same as in Example 1.

[0071] Compare with Example 2

[0072] The difference from Example 1 is that activated carbon fiber is used instead of bamboo fiber in Example 1;

[0073] The other steps and parameters are basically the same as in Example 1.

[0074] Compare with Example 3

[0075] The difference from Example 1 is that water-soluble chitosan is used instead of acid-soluble chitosan in Example 1;

[0076] The other steps and parameters are basically the same as in Example 1.

[0077] Compare with Example 4

[0078] The difference from Example 1 is that sodium carboxymethyl cellulose is used instead of sodium alginate in Example 1;

[0079] The other steps and parameters are basically the same as in Example 1.

[0080] Compare with Example 5

[0081] The difference from Example 1 is that: after mixing solution A containing bamboo fiber with solution B, the mixture is heated at 180°C for 8 hours to prepare a water softening material;

[0082] The other steps and parameters are basically the same as in Example 1.

[0083] Experimental Example 1

[0084] Figure 1 The image shows the appearance of the water softening material of this invention. As can be seen from the image, the finished water softening material resembles a fishing net and has low resistance in water.

[0085] like Figure 2 As shown, a homemade water softening device is constructed using two 1cm inner diameter PE hoses. One end of one hose is inserted into the water to be softened, and the other end is connected to the inlet of a self-priming pump. One end of the other hose is connected to the outlet of the self-priming pump, and the other end is filled with the softening material. A collection bucket can be attached to the end of the hose. The performance of the water softening material is evaluated by testing the quality of the water before and after purification.

[0086] Table 1. Water quality test results before and after water softening in Example 1

[0087] Testing items Pretreatment concentration (ppm) Post-treatment concentration (ppm) Softening efficiency % calcium ions 200 3.84 98.08 magnesium ions 150 2.93 98.04 lead ions 200 0.21 99.90 Cadmium ions 200 3.91 98.05 Chromium ions 200 5.78 97.11 Mercury ions 50 2.12 95.76 copper ions 200 3.81 98.10

[0088] Table 2. Water quality test results before and after water softening in Comparative Example 1.

[0089] Testing items Pretreatment concentration (ppm) Post-treatment concentration (ppm) Softening efficiency % calcium ions 200 25.2 87.40 magnesium ions 150 18.99 87.34 lead ions 200 22.2 88.90 Cadmium ions 200 26.98 86.51 Chromium ions 200 29.28 85.36 Mercury ions 50 13.79 72.42 copper ions 200 25.9 87.05

[0090] Table 3. Water quality test results before and after water softening in Comparative Example 2.

[0091] Testing items Pretreatment concentration (ppm) Post-treatment concentration (ppm) Softening efficiency % calcium ions 200 24.2 87.90 magnesium ions 150 18.89 87.41 lead ions 200 21.9 89.05 Cadmium ions 200 25.12 87.44 Chromium ions 200 26.98 86.51 Mercury ions 50 10.32 79.36 copper ions 200 24.02 87.99

[0092] Table 4. Water quality test results before and after softening in Comparative Example 3.

[0093]

[0094]

[0095] Table 5. Water quality test results before and after water softening in Comparative Example 4.

[0096] Testing items Pretreatment concentration (ppm) Post-treatment concentration (ppm) Softening efficiency % calcium ions 200 49.5 75.25 magnesium ions 150 34.83 76.78 lead ions 200 35.72 82.14 Cadmium ions 200 35.74 82.13 Chromium ions 200 39.34 80.33 Mercury ions 50 20.62 58.76 copper ions 200 34.32 82.84

[0097] Table 6. Water quality test results before and after softening in Comparative Example 5.

[0098] Testing items Pretreatment concentration (ppm) Post-treatment concentration (ppm) Softening efficiency % calcium ions 200 5.96 97.02 magnesium ions 150 5.03 96.65 lead ions 200 0.75 99.62 Cadmium ions 200 6.07 96.96 Chromium ions 200 7.89 96.06 Mercury ions 50 5.21 89.58 copper ions 200 5.92 97.04

[0099] As shown in Tables 1-6, the water softening material of the present invention can effectively adsorb and reduce the concentration of calcium and magnesium ions in water, as well as common heavy metal ions such as lead, cadmium, chromium, mercury and copper, while also having excellent treatment effects on ammonia nitrogen and nitrite.

[0100] However, in Comparative Example 1, sepiolite fiber was used instead of bamboo fiber in this invention. Although the surface of sepiolite fiber also has abundant hydroxyl groups, it is a silicate mineral and has poor cross-linking with sodium alginate / chitosan. The effective components are easily desorbed, resulting in the water softening material prepared in Comparative Example 1 having a poor water softening effect.

[0101] In Comparative Example 2, activated carbon fiber was used instead of bamboo fiber in Example 1. Although the surface of activated carbon fiber contains abundant carboxyl, phenolic hydroxyl, and carbonyl groups, its inherent properties make it difficult to promote the interaction with sodium alginate / chitosan. Furthermore, the active ingredients are easily desorbed in water. Therefore, the water softening material prepared from activated carbon fiber has a poor water softening effect. It should be further noted that the bamboo fiber selected in this invention cannot be replaced by any other fiber.

[0102] In Comparative Example 3, water-soluble chitosan was used instead of acid-soluble chitosan in Example 1. Water-soluble chitosan loses a large number of amino groups after modification, resulting in a lack of effective amino groups compared to acid-soluble chitosan. Therefore, the water softening material prepared in this way has slightly worse water softening performance than that of Example 1.

[0103] In Comparative Example 4, sodium carboxymethyl cellulose was used instead of sodium alginate in Example 1. Similarly, although sodium carboxymethyl cellulose has abundant carboxyl functional groups on its surface, it has the disadvantage of insufficient viscosity. Its effective components desorb, which is visible to the naked eye. Therefore, the water softening material prepared in this way has a poor water softening effect.

[0104] In Comparative Example 5, although solution A containing bamboo fiber was mixed with solution B and subjected to high-temperature heat treatment, it did not pass through a high-pressure reactor and immediately vent water vapor. This means that the surface of the modified bamboo fiber was not made more porous. This demonstrates that the expansion and water vapor extraction optimizes the shaping of the modified bamboo fiber, which to some extent reduces the resistance of the water softening material to the reaction in water and indirectly improves its adsorption, exchange, complexation, and chelation capabilities.

[0105] Experimental Example 2

[0106] The water softening material from Example 1, which had already undergone water softening, was soaked in low-concentration white vinegar for approximately 0.5 hours and shaken. Following the method described in the experimental example, the effectiveness of recycling and reusing the water softening material was tested. The test results are shown in Table 7.

[0107] Table 7 Test Results

[0108] Testing items Pretreatment concentration (ppm) Post-treatment concentration (ppm) Softening efficiency % calcium ions 200 4.48 97.76 magnesium ions 150 5.97 96.02 lead ions 200 2.58 98.71 Cadmium ions 200 7.96 96.02 Chromium ions 200 13.84 93.08 Mercury ions 50 2.67 94.67 copper ions 200 5.58 97.21

[0109] Experimental Example 2

[0110] The water softening material from Experiment 1, which had already undergone water softening, was treated again with the same dilute acid and then placed in an ultrasonic oscillator at an appropriate frequency for 3 hours. Following the method described in Experiment 1, the recycling and reuse effect of the water softening material was tested. The test results are shown in Table 8.

[0111] Table 8 Test Results

[0112] Testing items Pretreatment concentration (ppm) Post-treatment concentration (ppm) Softening efficiency % calcium ions 200 4.43 97.79 magnesium ions 150 5.93 96.05 lead ions 200 2.21 98.90 Cadmium ions 200 6.54 96.73 Chromium ions 200 11.32 94.34 Mercury ions 50 2.54 94.92 copper ions 200 5.45 97.28

[0113] As shown in Tables 7-8, the water softening material prepared by this invention can be reused after being soaked and stirred in dilute acid and then washed by ultrasonic vibration, and the softening effect is barely close to the initial effect.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water softening material, characterized in that, The ingredients include the following parts by weight: Bamboo fiber 10-50 parts, chitosan 2-10 parts, sodium alginate 1-5 parts and sodium humate 1-5 parts; The method for preparing the water softening material includes the following steps: S1. Add the catalyst to the aqueous solution of sodium alginate, stir and dissolve it thoroughly, then add bamboo fiber, and stir and heat it in sequence. The hydroxyl groups on the surface of bamboo fiber react with the carboxyl groups on the surface of sodium alginate to obtain solution A containing bamboo fiber. S2. Add sodium humate to the aqueous solution of chitosan, stir and mix thoroughly to obtain solution B; S3. After mixing solution A containing bamboo fiber with solution B, place them in a high-pressure reactor for hot drying and expansion. The ester groups on the surface of the modified bamboo fiber and the amino groups on the surface of chitosan undergo an amidation reaction to obtain a water softening material. There is no restriction on the order of steps S1 and S2.

2. The water softening material according to claim 1, characterized in that, The catalyst is 0.5-2 parts, and the catalyst includes any one of disodium hydrogen phosphate and sodium dihydrogen phosphate.

3. The water softening material according to claim 1, characterized in that, It also includes 0.5-2 parts of an acidic solution, wherein the acidic solution includes any one of dilute acetic acid, dilute hydrochloric acid, dilute sulfuric acid and dilute nitric acid.

4. The water softening material according to claim 1, characterized in that, The chitosan is acid-soluble chitosan.

5. A method for preparing the water softening material according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Add the catalyst to the aqueous solution of sodium alginate, stir and dissolve it thoroughly, then add bamboo fiber, and stir and heat it in sequence. The hydroxyl groups on the surface of bamboo fiber react with the carboxyl groups on the surface of sodium alginate to obtain solution A containing bamboo fiber. S2. Add sodium humate to the aqueous solution of chitosan, stir and mix thoroughly to obtain solution B; S3. After mixing solution A containing bamboo fiber with solution B, place them in a high-pressure reactor for hot drying and expansion. The ester groups on the surface of the modified bamboo fiber and the amino groups on the surface of chitosan undergo an amidation reaction to obtain a water softening material. There is no restriction on the order of steps S1 and S2.

6. The preparation method according to claim 5, characterized in that, In step S1, the heating treatment is performed at a temperature of 80-120℃ for 3-7 hours.

7. The preparation method according to claim 5, characterized in that, In step S2, chitosan is mixed with water, then an acidic solution is added, and the mixture is stirred thoroughly for 4-8 hours to obtain an aqueous solution of chitosan.

8. The preparation method according to claim 5, characterized in that, In step S2, sodium humate is added to the aqueous solution of chitosan, and the pH is adjusted and waited until it reaches 6.5-7.

5.

9. The preparation method according to claim 5, characterized in that, In step S3, during the hot drying and puffing process, the temperature is controlled at 160-200℃ and the time is 8-16 hours, and water vapor needs to be discharged in a timely manner during the process.

10. The preparation method according to claim 5, characterized in that, The water softening material can be recycled after being soaked and stirred in dilute acid, subjected to ultrasonic vibration, or washed.

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