Novel corrosion-resistant slow-release product for urine wastewater and preparation method thereof

Abstract

The invention belongs to the technical field of urine wastewater treatment, and particularly discloses a novel corrosion-resistant slow-release product for urine wastewater and a preparation method of the novel corrosion-resistant slow-release product. Sucrose, isomaltitol, a Kathon solution, citric acid, sorbic acid, benzoic acid and sodium benzoate are used as main raw materials to prepare a sustained-release product. The slow-release product has the effects of preventing corrosion and odor of urine. The slow-release block can effectively inhibit hydrolysis of urea in urine wastewater, and has good corrosion-resistant and odor-resistant effects; the hardness is higher, and powder is not easy to crack after long-time storage; the dissolvability is good, the toxicity is low and the environment-friendly effect is realized. The method is simple in preparation process flow, high in repeatability, low in equipment requirement, low in production cost and easy for industrial batch production.

Description

Technical Field

[0001] The present invention belongs to the technical field of urine wastewater treatment, and particularly relates to a novel slow-release product for anti-corrosion of urine wastewater and a preparation method thereof. Background Art

[0002] In the process of urine resource utilization and urine collection, the traditional method adopts the non-water flushing toilet technology. This technology has high requirements for the environment. Moreover, due to the existence of urease, urea in urine is hydrolyzed to release volatile ammonia and carbon dioxide, resulting in nitrogen loss and at the same time generating a pungent ammonia smell. Urea is a stable compound. In an aqueous medium at room temperature, the half-life of uncatalyzed decomposition is 3.6 years. The hydrolysis rate of urea depends on the content of urease, and the content of urease is affected by pH value and temperature. Research shows that both high pH and high temperature can cause an increase in urease, thus accelerating urea hydrolysis. So far, various strategies for preventing urea hydrolysis have been explored, including adding acid or alkali, adding urease inhibitors, and electrochemical treatment. Although these methods have been proven effective, they all have their own limitations. The optimal activity range of bacterial urease is between pH 6.8 - 8.7, so a pH value less than 4 or greater than 12 can effectively inhibit urea hydrolysis.

[0003] Currently, urine anti-corrosion is mainly achieved by adding artificial camphor balls to urinals or adding a certain proportion of Kathon preservative solution to urine collection buckets. Artificial camphor balls can prevent moths, mildew, and deodorize. Its main component is 1,4-dichlorobenzene. Kathon preservative is an excellent broad-spectrum bactericide, which has a good inhibitory effect on yeasts, fungi, Gram-positive bacteria, heterotrophic bacteria, algae, etc., and is widely used in bactericidal and anti-corrosion treatments. Its main components are a mixture of 2-methyl-4-isothiazolin-3-one (MI) and 2-methyl-5-chloro-4-isothiazolin-3-one (CMI) and a little magnesium chloride and magnesium nitrate as stabilizers. However, in practical applications, relying solely on camphor balls cannot achieve urine anti-corrosion, and the Kathon preservative has problems such as untimely dosing and inability to act on pipe bends, which will reduce the bactericidal effect of Kathon. Some researchers mixed artificial camphor powder, Kathon solution, and citric acid solution in a certain proportion, and utilized the characteristic that synthetic camphor powder is easy to solidify at room temperature to convert the Kathon liquid and citric acid solution into solids, while playing a slow-release role, prolonging the anti-corrosion and deodorization time of Kathon and synthetic camphor, and increasing their effect. However, this method is not suitable for mass production because camphor is easy to solidify, has poor plasticity, and the production process is slow, and it is only suitable for small-scale production. Summary of the Invention

[0004] The object of the present invention is to provide a synthesis method of a novel slow-release block with low cost, easy operation, mass producibility, and bactericidal and deodorizing functions. Aiming at the problems that the Kathon preservative cannot act on the urine at the pipe bend during use, there are problems such as untimely addition, insufficient addition or excessive addition, and the artificial synthetic camphor balls cannot play a bactericidal role, and the previous slow-release products have low plasticity and cannot be used on a large scale. The present invention mixes sucrose, isomaltitol, Kathon solution, citric acid, sorbic acid, benzoic acid, sodium benzoate, and camphor balls in a certain proportion. Using sucrose and isomaltitol as carriers, they dissolve at high temperature and solidify when cooled to room temperature. Using Kathon, sorbic acid, and sodium benzoate as preservatives, using citric acid as a bactericide to remove scale on the inner wall of the pipe, and using benzoic acid as a plasticizer, finally obtaining a novel slow-release product, which plays a slow-release role, prolongs the anti-corrosion and deodorization time of synthetic camphor and Kathon, etc., and increases its effect of inhibiting urea hydrolysis.

[0005] To solve the technical problems in the above background, the present invention proposes a novel slow-release product for urine wastewater anti-corrosion. In terms of mass concentration, it mainly includes the following components: sucrose 4.73%-11.29%, isomaltitol 30.71%-56.31%, Kathon 10.16%-11.94%, citric acid 3.69%-6.76%, sodium benzoate 4.10%-5.18%, water 15.09%-40.95%;

[0006] And camphor balls, which are directly added to the mold in advance in units of grains;

[0007] The purity of the sucrose is 95%;

[0008] The isomaltitol is food grade, with a purity of 95% and a sweetness of 50%-60% of sucrose;

[0009] The Kathon is a mixture of 2-methyl-4-isothiazolin-3-one (MI) and 2-methyl-5-chloro-4-isothiazolin-3-one (CMI);

[0010] The purity of the citric acid is 99.5%;

[0011] The purity of sodium benzoate is 98%;

[0012] The camphor balls are artificial synthetic camphor balls, and their main components are one or a mixture of 1,4-dichlorobenzene or natural camphor powder.

[0013] Furthermore, it also contains sorbic acid, with a content ≤0.04% in terms of mass concentration, and the purity of sorbic acid is 99%.

[0014] Furthermore, it also contains benzoic acid, with a content ≤0.04% in terms of mass concentration, and the purity of benzoic acid is 99%.

[0015] The novel sustained-release product is a sustained-release block with a weight of 20 - 50 g, a diameter of 4.9 cm - 5.7 cm, and a thickness of 1.2 cm - 2.8 cm.

[0016] Another technical solution proposed by the present invention is a preparation method of a novel sustained-release product for urine wastewater anti-corrosion, comprising the following steps:

[0017] (1) First, weigh sodium benzoate, dissolve it in water to prepare a sodium benzoate solution, and add camphor balls into the mold in units of grains;

[0018] (2) Add water to the reactor and preheat it to 170 ± 10 °C;

[0019] (3) Weigh sucrose, isomaltulose, and citric acid in proportion and add them to the reactor in sequence;

[0020] (4) Add the sodium benzoate solution dissolved in step (1) to the reactor and stir;

[0021] (5) Continuously heat, and when the color of the system turns brown, add Kathon;

[0022] (6) When the color of the system turns brownish green, stop heating;

[0023] (7) When the color of the system turns brownish yellow, stop stirring, pour it into the mold, and cool it to form;

[0024] The mass ratio of the sucrose to the isomaltulose is 1:4 - 1:15;

[0025] The purity of the sucrose is 95%;

[0026] The isomaltulose is food grade with a purity of 95%.

[0027] The heating temperature in step (5) is 150 - 170 °C.

[0028] The mass ratio of the sucrose to the isomaltulose is 1:6 - 1:12.

[0029] Furthermore, the main components include, by mass concentration: sucrose 4.73% - 11.29%, isomaltulose 30.71% - 56.31%, Kathon 10.16% - 11.94%, citric acid 3.69% - 6.76%, sodium benzoate 4.10% - 5.18%, and water 15.09% - 40.95%.

[0030] Sorbic acid is added in step (3) with a content ≤ 0.04% by mass concentration.

[0031] Benzoic acid is added in step (3) with a content ≤ 0.04% by mass concentration.

[0032] Compared with traditional methods, this new type of sustained-release product has the following advantages: Sucrose is highly soluble in water, odorless, and has strong plasticity; Isomalt is odorless, not easily hydrolyzed, and has low viscosity. Mixing sucrose and isomalt in a certain proportion gives play to their respective advantages and overcomes the problems existing in previous sustained-release products. Citric acid can quickly remove scale on the inner wall of the pipeline and sterilize, specifically shown as:

[0033] 1. Prolong the time for the anti-corrosion and anti-odor effects of synthetic camphor, Kathon, etc., and increase its effect of inhibiting urea hydrolysis;

[0034] 2. Effectively target urine at the pipeline bends and play a role in sterilization and anti-corrosion;

[0035] 3. Low cost, easy to operate, can be mass-produced, and has high industrial value.

[0036] 4. Adding sorbic acid enables highly efficient, safe anti-corrosion and preservation; Benzoic acid is mainly used for plasticization and sterilization. Description of the Drawings

[0037] Figure 1 is the process flow chart of the new type of sustained-release product;

[0038] Figure 2 is the physical diagram of the sustained-release product: a and b are the vertical and horizontal angle views of the sustained-release block respectively;

[0039] Figure 3 is the physical diagram of the mold;

[0040] Figure 4 is the physical diagram of the reactor;

[0041] Figure 5 is the physical diagram of the color change of the sustained-release block in Example 3: where the time starts and ends with the heating time;

[0042] Figure 6 is the physical diagram of the sustained-release block inhibiting urine corrosion in Example 3: from left to right are the original urine, urine with the sustained-release block placed for seven days, and urine with freezing and placed for seven days.

[0043] Figure 7 is the statistical chart of (a) the dissolution rate (uM) of Kathon, (b) the mass reduction rate (%) of the sustained-release block, and (c) the inhibition efficiency (%) of ammonia nitrogen in each example. Detailed Embodiments

[0044] The following further clarifies the present invention in combination with examples and drawings. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. After reading the present invention, various equivalent modifications made by those skilled in the art to the present invention fall within the scope defined by the appended claims of this application.

[0045] The sucrose, isomaltitol, Kathon solution, citric acid, sorbic acid, benzoic acid, sodium benzoate, and camphor balls used in the present invention are all commercially available products. The diameter of the mold is 5 cm - 5.8 cm, and the height is 2.3 cm - 3.3 cm

[0046] The present invention will be further described below through specific embodiments and drawings:

[0047] Example 1

[0048] Proportion of the sustained-release block material:

[0049] 20 mL of Kathon, 20 g of citric acid, 200 g of camphor balls, 1 g of sorbic acid, 1 g of benzoic acid;

[0050] Operating steps:

[0051] (1) Take 20 mL of Kathon in a glass reagent bottle, heat it at 160 °C for 30 min, and evaporate to about 3 mL;

[0052] (2) Add 20 g of citric acid, 200 g of camphor balls, 1 g of sorbic acid, and 1 g of benzoic acid, heat at 180 °C for about 10 min, stir until the camphor completely melts;

[0053] (3) Pour the above solution into the mold, cool to room temperature, and demold to obtain the sustained-release product of the mixture of camphor balls and Kathon, and store it in a sealed bag.

[0054] Testing of the release rate of the sustained-release block, mass change of the sustained-release block, and pH:

[0055] In order to measure the release rate of the effective bactericidal component Kathon preservative in the sustained-release block, an experiment of rinsing the sustained-release block with urine during actual use was simulated, and the effective concentration of Kathon in the rinsing solution was tested using a high-performance liquid chromatograph. Since the composition of urine is complex, the use of real urine cannot accurately monitor the effective concentration of Kathon by a high-performance liquid chromatograph. Therefore, in this experiment, deionized water was used instead of urine to rinse the sustained-release block and then test the effective concentration of Kathon released. First, place the sustained-release block in a conical funnel, and place a beaker under the funnel. Slowly pour 1 L of deionized water from a height of 1 m to rinse the sustained-release block. The rinsing time lasts about 60 s, and rinse three times continuously. Then, use a high-performance liquid chromatograph to measure the concentrations of Kathon, sorbic acid, and benzoic acid in the rinsing solution after rinsing. Weigh the sustained-release block before and after being rinsed with a balance, and measure the pH of the sustained-release block before and after being rinsed with a pH meter. The test results are shown in Table 1:

[0056]

[0057] Table 1

[0058] It can be seen from Table 1 that the dissolution rate of Kathon in the eluent is low, and a good anti-corrosion effect cannot be achieved.

[0059] Example 2

[0060] Proportion of slow-release block material:

[0061] In a 20 g sucrose system, there are 20 g of sucrose; 5 mL of Kathon; 1.8 g of citric acid; 2 g of sodium benzoate; 0.02 g of sorbic acid; 0.02 g of benzoic acid; directly heat to a temperature of 200 °C;

[0062] Operation steps:

[0063] Directly heat the sucrose in an oil bath for 1 h (200 °C), then add 125 mL of Kathon, 45 g of citric acid, 50 g of sodium benzoate, 0.5 g of sorbic acid, and 0.5 g of benzoic acid, and continuously stir. Pour it into a mold, place a camphor ball in the middle of each mold, cool and form, and demold to obtain the slow-release block. It was found during the stirring process that the last added components could not be evenly dissolved, and the formed slow-release block was also layered, and the later added components were distributed in the top layer.

[0064] Testing of the release rate, mass change of the slow-release block, and pH:

[0065] Measure the release rates of the effective bactericidal components Kathon, sorbic acid, and benzoic acid in the slow-release block. The measurement method is the same as that in Example 1. Weigh the slow-release block before and after being washed with a balance, and measure the pH of the slow-release block before and after being washed with a pH meter. The test results are as

[0066] shown in Table 2:

[0067]

[0068] Table 2

[0069] It can be seen from Table 2 that using sucrose as the carrier, the dissolution rate of Kathon in the eluent is low, and a good anti-corrosion effect cannot be achieved. Moreover, the change rate of the slow-release block is extremely fast, and it is difficult to be utilized for a long time.

[0070] Example 3

[0071] Proportion of slow-release block material:

[0072] In a 20 g isomaltitol system, there are 20 g of isomaltitol; 15 mL of Kathon; 1.8 g of citric acid; 0.02 g of sorbic acid; 0.02 g of benzoic acid; directly heat to a temperature of 100 - 160 °C;

[0073] Operation steps:

[0074] First, add water to an iron pot and directly heat it to boiling. Then add 500 g of isomaltitol, 375 mL of Kathon, 45 g of citric acid, 0.5 g of sorbic acid, and 0.5 g of benzoic acid, and continuously stir. Since the amount of Kathon is three times that of the original this time, the time to reach the previous optimum is also extended to about 50 min. At this time, pour it into a mold, place a camphor ball in the middle of each mold, cool and form, and then demold to obtain the sustained-release block.

[0075] Testing of the release rate, mass change and pH of the sustained-release block:

[0076] Determine the release rates of the effective bactericidal components Kathon, sorbic acid, and benzoic acid in the sustained-release block. The determination method is the same as that in Example 1. Weigh the weight of the sustained-release block before and after being washed with a balance, and measure the pH of the sustained-release block before and after being washed with a pH meter. The test results are as

[0077] shown in Table 3:

[0078]

[0079] Table 3

[0080] It can be seen from Table 3 that using isomaltitol as the carrier, the dissolution rate of Kathon in the eluent is relatively low.

[0081] Example 4

[0082] Proportion of the sustained-release block material:

[0083] In a 20 g system, sucrose:isomaltitol = 1:1, that is, 10 g of sucrose and 10 g of isomaltitol; 5 mL of Kathon; 1.8 g of citric acid; 2 g of sodium benzoate, 0.02 g of sorbic acid; 0.02 g of benzoic acid; moisten with a small amount of water, and control the temperature at 130 - 140 °C;

[0084] Operating steps:

[0085] Add 10 g of sucrose, 10 g of isomaltitol, 5 mL of Kathon, 1.8 g of citric acid, 2 g of sodium benzoate, 0.02 g of sorbic acid, and 0.02 g of benzoic acid to a 250 mL glass bottle, moisten with a small amount of water, boil for half an hour at 130 - 140 °C, and continuously stir. The system will change from the original light blue color to caramel color. When the sugar becomes sticky, pour it into a mold at this time, place a camphor ball in the middle of each mold, cool and form, and then demold to obtain the sustained-release block.

[0086] Testing of the release rate, mass change and pH of the sustained-release block:

[0087] Determine the release rates of the effective bactericidal components Kathon, sorbic acid, and benzoic acid in the sustained-release block. The determination method is the same as that in Example 1. Weigh the weight of the sustained-release block before and after being washed with a balance, and measure the pH of the sustained-release block before and after being washed with a pH meter. The test results are as

[0088] As shown in Table 4:

[0089]

[0090] Table 4

[0091] It can be obtained from Table 4 that when sucrose and isomaltulose are combined in a ratio of 1:1, the dissolution rate of Kathon in the eluent is relatively high, and the effect is improved compared with before. However, the change rate of the sustained-release block is extremely fast, and it is difficult to utilize for a long time.

[0092] Example 5

[0093] Proportion of sustained-release block material:

[0094] Sucrose: 5 kg, isomaltulose 20 kg, sucrose:isomaltulose = 1:4, citric acid 1.8 kg, sodium benzoate 2 kg, Kathon 4.5 kg, water 11 kg;

[0095] Operation steps:

[0096] (1) First, dissolve 2 kg of sodium benzoate in 5 kg of water and stir to make it dissolve in the system faster to prevent it from agglomerating. Add 1 camphor ball to each mold;

[0097] (2) Add 6 kg of water (total 11 kg of water) to the reactor, start heating, and set the temperature to 170 °C;

[0098] (3) Add 5 kg of sucrose, 20 kg of isomaltulose, 1.8 kg of citric acid, and the sodium benzoate solution dissolved in step (1) in sequence, and start stirring;

[0099] (4) Keep heating at 160 °C. After 1 h, when the color of the system turns brown, add 4.5 kg of Kathon;

[0100] (5) When the color of the system turns brownish green, stop heating;

[0101] (6) When the color of the system turns brownish yellow, stop stirring, take out of the pot, and pour into the mold;

[0102] Sustained-release rate of the sustained-release block, change in the quality of the sustained-release block, and pH test:

[0103] Measure the release rates of the effective bactericidal components Kathon and benzoic acid in the sustained-release block. The measurement method is the same as that in Example 1. Weigh the sustained-release block before and after being washed with a balance, and measure the pH of the sustained-release block before and after being washed with a pH meter. The test results are shown in Table 5:

[0104]

[0105] Table 5

[0106] It can be seen from Table 5 that the colors of the eluent and the sustained-release block are both dark brown; the color is relatively dark, and the dissolution rate of Kathon is relatively high, but at the same time, the dissolution rate of the sustained-release block is too fast.

[0107] Example 6

[0108] Proportion of the sustained-release block material:

[0109] Sucrose: 4.2 kg, isomaltitol 25 kg, sucrose: isomaltitol = 1:6, citric acid 2.1 kg, sodium benzoate 2.3 kg, Kathon 5.3 kg, water 12 kg;

[0110] Operation steps:

[0111] (1) First, dissolve 2.3 kg of sodium benzoate in 5 kg of water with stirring to make it dissolve into the system faster and prevent it from coagulating into lumps, and add 1 camphor ball to each mold;

[0112] (2) Add 7 kg of water (total 12 kg of water) to the reactor, start heating, and set the temperature to 170 °C;

[0113] (3) Add 4.2 kg of sucrose, 25 kg of isomaltitol, 2.1 kg of citric acid, and the sodium benzoate solution dissolved in step (1) in sequence, and start stirring;

[0114] (4) Keep heating at 170 °C. After 1 h, when the color of the system turns brown, add 5.3 kg of Kathon;

[0115] (5) When the color of the system turns brownish green, stop heating;

[0116] (6) When the color of the system turns brownish yellow, stop stirring, take out of the pot, and pour into molds;

[0117] Sustained-release rate of the sustained-release block, change in weight of the sustained-release block, and pH test:

[0118] Measure the release rates of the effective bactericidal components Kathon and benzoic acid in the sustained-release blocks with different color depths. The measurement method is the same as that in Example 1. Weigh the weight of the sustained-release block before and after being washed with a balance, and measure the pH of the sustained-release block before and after being washed with a pH meter. The test results are shown in Tables 6 and 7:

[0119]

[0120] Table 6

[0121]

[0122] Table 7

[0123] It can be seen from Tables 6 and 7 that the darker the color, the higher the dissolution rate of Kathon. Compared with before, when the proportion of sucrose is reduced, the dissolution rate of Kathon decreases accordingly.

[0124] Example 7

[0125] Proportion of the sustained-release block material:

[0126] Sucrose: 2.1 kg, isomaltitol 25 kg, sucrose: isomaltitol = 1:12, citric acid 3 kg, sodium benzoate 2.3 kg, Kathon 5.3 kg, water 6.7 kg;

[0127] Operation steps:

[0128] (1) First, dissolve 2.3 kg of sodium benzoate in 5 kg of water by stirring to enable it to blend into the system faster and prevent it from agglomerating. Add 1 camphor ball to each mold;

[0129] (2) Add 2.7 kg of water (total water is 6.7 kg) to the reactor, start heating, and set the temperature to 170 °C;

[0130] (3) Add 2.1 kg of sucrose, 25 kg of isomaltitol, 3 kg of citric acid, and the sodium benzoate solution dissolved in step (1) in sequence, and start stirring;

[0131] (4) Keep heating at 150 °C. After 1 h, when the color of the system turns brown, add 5.3 kg of Kathon;

[0132] (5) When the color of the system turns brownish green, stop heating;

[0133] (6) When the color of the system turns brownish yellow, stop stirring, take out of the pot, and pour into the mold;

[0134] Testing of the release rate of the sustained-release block, weight change of the sustained-release block, and pH:

[0135] Measure the release rates of the effective bactericidal components Kathon and benzoic acid in the sustained-release blocks with different color shades. The measurement method is the same as that in Example 1. Weigh the sustained-release block before and after being washed with a balance, and measure the pH of the sustained-release block before and after being washed with a pH meter. The test results are shown in Tables 8 and 9:

[0136]

[0137] Table 8

[0138]

[0139] Table 9

[0140] Figure 2 For the color change of the sustained-release block during the production process, from Tables 8, 9 and Figure 2It can be concluded that the darker the color, the higher the dissolution rate of Kathon, but at the same time, the faster the dissolution rate of the sustained-release block. The difference in the color of the sustained-release blocks between Table 8 and Table 9 lies in the demolding time. Antiseptic test of the sustained-release block on urine:

[0141] In Table 10, it is found that the reduction ranges of ammonia nitrogen in the urine with the added sustained-release block are all smaller than those by the freezing method. Especially in Example 7, the ammonia nitrogen in the urine is reduced by 11%, while by the freezing method, the ammonia nitrogen is reduced by 18.6%, indicating that the sustained-release block can inhibit urea hydrolysis.

[0142]

[0143] Table 10

[0144] As Figure 6 shown, from the figure of the sustained-release block in Example 7 inhibiting urine corrosion, it can be seen that compared with the original urine, the color of the urine in the group with the added sustained-release block changes little after seven days, while the color of the urine in the frozen group changes significantly, indicating that the sustained-release block has an antiseptic effect on urine, that is, it inhibits urea hydrolysis.

[0145] From Figure 7 it can be seen that the dissolution rate of Kathon with sucrose:isomaltulose = 1:4 is the highest, but its sustained-release block reduces too fast to meet the usage requirements. The inhibitory effect on urea with sucrose:isomaltulose = 1:1 is the best, but its sustained-release block also reduces too fast and cannot meet the usage requirements either. Isomaltulose determines the reduction rate of the sustained-release block. Compared with sucrose, it is not easily hydrolyzed. When sucrose:isomaltulose = 1:12, the reduction rate of the sustained-release block reaches the lowest. When sucrose:isomaltulose = 1:1, the inhibitory effect on urea is the best. Considering the factors of the dissolution rate (uM) of Kathon, the mass reduction rate of the sustained-release block, and the inhibitory efficiency on ammonia nitrogen, when sucrose:isomaltulose = 1:12, it can not only ensure the dissolution concentration of Kathon, achieve the purpose of well inhibiting urea hydrolysis, but also extend the utilization time of the sustained-release block, which is the best solution. Continuing to increase the concentration of isomaltulose will reduce the dissolution concentration of Kathon and affect the inhibitory effect on urea.

Claims

1. A novel slow-release product for urine wastewater anti-corrosion, characterized in that, By mass concentration, it mainly includes the following components: Sucrose 4.73% - 11.29%, isomaltitol 30.71% - 56.31%, Kathon 10.16% - 11.94%, citric acid 3.69% - 6.76%, sodium benzoate 4.10% - 5.18%, water 15.09% - 40.95%; And camphor balls, which are directly added to the mold in advance in units of grains; The purity of the sucrose is 95%; The isomaltitol is food grade, with a purity of 95% and a sweetness of 50% - 60% of sucrose; The Kathon is a mixture of 2-methyl-4-isothiazolin-3-one (MI) and 2-methyl-5-chloro-4-isothiazolin-3-one (CMI); The purity of the citric acid is 99.5%; The purity of sodium benzoate is 98%; The camphor balls are synthetic camphor balls, and their main components are one or a mixture of 1,4-dichlorobenzene or natural camphor powder.

2. The novel slow-release urine and wastewater anti-corrosion product according to claim 1, characterized in that, It also contains sorbic acid, with a content ≤ 0.04% by mass concentration, and the purity of sorbic acid is 99%.

3. The novel slow-release product for urine wastewater anti-corrosion according to claim 1, characterized in that, It also contains benzoic acid, with a content ≤ 0.04% by mass concentration, and the purity of benzoic acid is 99%.

4. The preparation method of the novel slow-release product for urine wastewater anti-corrosion according to claim 1, characterized in that, The new slow-release product is a slow-release block, with a weight of 20 - 50 g, a diameter of 4.9 cm - 5.7 cm, and a thickness of 1.2 cm - 2.8 cm.

5. The preparation method of the novel slow-release product for urine wastewater anti-corrosion according to any one of claims 1 to 4, characterized in that, It includes the following steps: (1) First, weigh sodium benzoate, dissolve it in water to prepare a sodium benzoate solution, and add camphor balls to the mold in units of grains; (2) Add water to the reactor and preheat it to 170 ± 10 °C; (3) Weigh sucrose, isomaltitol, and citric acid in proportion and add them to the reactor in sequence; (4) Add the sodium benzoate solution dissolved in step (1) to the reactor and stir; (5) Keep heating, and when the color of the system turns brown, add Kathon; (6) When the color of the system turns brownish green, stop heating; (7) When the color of the system turns brownish yellow, stop stirring, pour it into the mold, and cool it to form; The mass ratio of sucrose to isomaltitol = 1:4 - 1:15; The purity of the sucrose is 95%; The isomaltitol is food grade, with a purity of 95%.

6. The preparation method of the novel slow-release product for urine wastewater anti-corrosion according to claim 5, characterized in that, The heating temperature in step (5) is 150 - 170 °C.

7. The preparation method of the novel slow-release product for urine wastewater anti-corrosion according to claim 5, characterized in that, The mass ratio of sucrose to isomaltitol = 1:6 - 1:

12.

8. The preparation method of the novel slow-release product for urine wastewater anti-corrosion according to claim 5, characterized in that, By mass concentration, the main components include: sucrose 4.73% - 11.29%, isomaltitol 30.71% - 56.31%, Kathon 10.16% - 11.94%, citric acid 3.69% - 6.76%, sodium benzoate 4.10% - 5.18%, water 15.09% - 40.95%.

9. The preparation method of the novel slow-release product for urine wastewater anti-corrosion according to claim 5, characterized in that, Sorbic acid is added in step (3), with a content ≤ 0.04% by mass concentration.

10. The preparation method of the novel slow-release product for urine wastewater anti-corrosion according to claim 5, characterized in that, Benzoic acid is added in step (3), with a content ≤ 0.04% by mass concentration.

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