Water treatment method after spraying rust prevention of holder
By combining modified activated carbon and modified chitosan, the problem of removing impurities and metal ions from wastewater after cage spraying for rust prevention was solved, achieving efficient utilization of water resources and rust inhibitors and reducing production costs.
Patent Information
- Application Number
- CN202511994003.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-03-10
AI Technical Summary
Existing technologies are insufficient to effectively remove particulate impurities and metal ions from wastewater after rust prevention spraying of cages, while maintaining the stability and utilization rate of water-based rust inhibitors, resulting in waste of water resources and rust inhibitors.
A combined treatment method using modified activated carbon and modified chitosan was adopted. Through pH adjustment, adsorption by modified activated carbon, and complexation by modified chitosan, particulate impurities and metal ions in wastewater were removed, respectively, while maintaining the activity and stability of the rust inhibitor and improving its retention rate in the treated water.
It significantly reduces the content of suspended solids and metal ion concentration in wastewater, improves the utilization rate of water resources and rust inhibitors, and reduces production costs.
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Abstract
Description
Technical Field
[0001] This application relates to a water treatment method after rust prevention spraying of a cage, belonging to the field of industrial wastewater treatment technology. Background Technology
[0002] In the bearing manufacturing industry, the cage, as a crucial component that isolates and guides the rolling elements, directly impacts the bearing's assembly accuracy and service life due to its rust protection. Spray rust prevention, due to its high efficiency and uniform protection, has become an important rust prevention treatment method in the later stages of cage processing. This process uses high-pressure spray equipment to evenly cover the cage surface with a rust inhibitor solution, forming a dense protective film that blocks oxygen and moisture from contacting the metal substrate, thereby inhibiting rust formation. However, during the spraying process, some rust inhibitor cannot completely adhere to the cage surface, resulting in rust-inhibiting wastewater that is washed away with the sprayed water.
[0003] Currently, rust inhibitors for cages are mainly divided into two categories: water-based and oil-based. Among them, water-based rust inhibitors are more widely used due to their superior environmental friendliness, ease of cleaning, and better suitability for subsequent wastewater reuse treatment. Their components usually include organic acids, amines, alcohols, surfactants, corrosion inhibitors, etc. The presence of surfactants and emulsifiers enhances the dispersion stability of rust inhibitors in water. Although this increases the difficulty of separation, it also provides a basis for their stable retention in water.
[0004] Traditional treatment methods mainly include coagulation-flotation and biological treatment. Coagulation-flotation removes impurities from wastewater by adding demulsifiers to break up the emulsion system, but it can also damage the active ingredients of rust inhibitors, affecting the reuse of treated water. Biological treatment, on the other hand, suffers from unstable treatment results because some components of rust inhibitors in wastewater are biodegradable and, combined with heavy metal ions, inhibit microbial activity. It cannot effectively retain rust inhibitors and also fails to meet the water quality requirements for wastewater reuse.
[0005] Therefore, there is an urgent need for a water treatment method that can reduce the content of particulate impurities and metal ions in wastewater, reduce the loss of water-based rust inhibitors, increase the amount of rust inhibitors in the treated water, and improve the utilization rate of water resources. Summary of the Invention
[0006] To address the aforementioned issues, a water treatment method is provided for the post-spray rust prevention of retainers. This method removes metal ions and particulate impurities from the wastewater, minimizing its impact on the water-based rust inhibitor system. It maximizes the retention of the water-based rust inhibitor in the treated water, allowing the treated water to be reused in the water-based rust inhibitor spraying process. This improves water resource utilization, reduces the amount of water-based rust inhibitor used, and consequently lowers production costs.
[0007] One aspect of this application provides a water treatment method for a cage after spraying rust prevention, comprising the following steps: (1) Add pH adjuster to the wastewater generated after spraying rust inhibitor to adjust the pH, and then perform a pressure filter to remove larger impurities in the wastewater. (2) The wastewater treated in step (1) is transported to the wastewater tank. The modified activated carbon is mixed with water to obtain the modified activated carbon mixture, which is then loaded into the medicine tank. The modified activated carbon mixture and the wastewater are then transported to the stirring tank respectively and stirred for 40-60 minutes. The modified activated carbon is obtained by modifying N-(2-aminoethyl)-3-aminopropyltriethoxysilane with trimethyl mercaptophosphate. (3) After the water treated in step (2) is filtered twice, it is then treated with modified chitosan and transported to a sedimentation tank. Sodium hypochlorite is added and the water is left to stand in the sedimentation tank for 1-1.5 hours to obtain the treated water. The modified chitosan is obtained by modification with salicylic acid and trihydroxybenzoic acid.
[0008] By adjusting the pH of wastewater, two things can be achieved: first, to maintain the stable activity of rust inhibitors and reduce the loss of active ingredients; second, to promote the aggregation and agglomeration of large particles such as metal scraps and iron oxide scale, so that large particles can be quickly and completely separated from the water through pressure filtration, thereby improving the impurity retention rate of the pressure filtration process, significantly reducing the suspended solids content in wastewater, and at the same time, adjusting the pH can also stabilize the rust inhibitors in the wastewater and improve their utilization rate.
[0009] Modified activated carbon can adsorb smaller-sized metal ions or colloidal suspended solids in wastewater, further reducing the content of impurities in wastewater and improving the wastewater treatment effect. Modified activated carbon contains amino and thiol groups, which form complexes with metal ions such as iron and aluminum in wastewater, improving the removal rate of metal ions. The various active groups contained in modified activated carbon do not have a significant destructive effect on the emulsion system of water-based rust inhibitors.
[0010] The wastewater was then filtered using modified chitosan. Salicylic acid contains hydroxyoxime and phenolic hydroxyl groups. The N and O atoms of the hydroxyoxime group have a positive effect on Fe. 2+ Fe 3+ It has a strong complexing effect, which can complex with metal ions and reduce the content of metal ions in wastewater. At the same time, salicylic acid does not affect the emulsion system of the rust inhibitor, so that the emulsion rust inhibitor can exist stably in the treated water and is easy to reuse.
[0011] Trihydroxybenzoic acid contains a catechol group and a carboxyl group; the two hydroxyl O atoms of the catechol pair with Al. 3+ It has strong chelating ability and effectively adsorbs Al in wastewater. 3+It reduces the content of metal ions in wastewater, and trihydroxybenzoic acid does not have a significant destructive effect on the emulsion system of rust inhibitors, allowing the rust inhibitors to remain stable in the treated wastewater.
[0012] Optionally, the stirring speed in the mixing tank in step (2) is 50-60 r / min.
[0013] At this stirring speed, the modified activated carbon can adsorb smaller particles of impurities in the wastewater. If the stirring speed is too fast, the modified activated carbon will not be able to adsorb smaller particles in time, resulting in unsatisfactory wastewater treatment. If the stirring speed is too slow, it will not only affect the wastewater treatment effect, but also prolong the wastewater treatment time.
[0014] Optionally, the amount of modified activated carbon added is 50-60 g / m³. 3 .
[0015] At this dosage, modified activated carbon can adsorb and complex impurity particles in wastewater with good effect. However, if the dosage of modified activated carbon is too large, it will not significantly improve the removal of impurities, but will instead increase production costs and burden the enterprise. If the dosage of modified activated carbon is too small, its effect on removing impurities from wastewater will be unsatisfactory.
[0016] Optionally, the modified activated carbon is prepared as follows: A1: Add activated carbon to an acidic solution, soak, filter and dry to obtain activated carbon; A2: Disperse the activated carbon in a solvent, then add N-(2-aminoethyl)-3-aminopropyltriethoxysilane, and stir at 60-70℃ for 2-3 hours to obtain activated carbon A; A3: Activated carbon A is dispersed in a solvent, then trimethyl mercaptophosphate is added and mixed evenly, and finally dried to obtain modified activated carbon.
[0017] When activated carbon is oxidized in an acidic solution, active groups such as hydroxyl and carboxyl groups are generated on its surface. These active groups react with N-(2-aminoethyl)-3-aminopropyltriethoxysilane to introduce amino groups. The amino groups can complex with pollutants such as heavy metal ions in the water, thereby removing them from the wastewater. At the same time, the surface stability of the activated carbon is improved, reducing the loss of activated carbon during water treatment and allowing the modified activated carbon to maintain high adsorption performance during use.
[0018] In addition, modified activated carbon contains thiol groups, which have a strong affinity for heavy metal ions and can form stable sulfide chelates. Even if the concentration of metal ions in wastewater is low, it can still complex the impurities of metal ions, further reducing the content of heavy metal ions in wastewater. Activated carbon also has a decolorizing effect, which can clarify the treated wastewater, make it easier to recycle and reuse, and improve the utilization rate of water resources.
[0019] Optionally, the mass ratio of the activated carbon to N-(2-aminoethyl)-3-aminopropyltriethoxysilane is 1:(0.5-0.7).
[0020] At this ratio, N-(2-aminoethyl)-3-aminopropyltriethoxysilane can react with the hydroxyl groups on activated carbon, introducing amino groups onto the activated carbon. This allows the amino groups to be evenly dispersed in the wastewater along with the activated carbon, thus achieving uniform dispersion of the amino groups in the wastewater. This enables the activated carbon to not only have an adsorption function but also to remove heavy metal ions that are difficult to remove from the wastewater by forming complexes with the introduced amino groups.
[0021] Optionally, the mass ratio of the functionalized activated carbon to trimethyl mercaptophosphate is 1:(0.3-0.4).
[0022] At this ratio, functionalized activated carbon and trimethyl mercaptophosphate can work synergistically. The functionalized activated carbon adsorbs colloidal impurities, while the thiol groups in trimethyl mercaptophosphate complex metal ions. Together, they improve the wastewater treatment effect.
[0023] Optionally, the amount of sodium hypochlorite added is 0.05-0.1 wt‰.
[0024] At this dosage, sodium hypochlorite hydrolyzes to produce a suitable amount of hypochlorous acid. Hypochlorous acid molecules are small and uncharged, allowing them to penetrate the interiors of bacteria, fungi, and other microorganisms, disrupting their enzyme systems and nucleic acid structures. This effectively kills harmful bacteria in wastewater caused by environmental microorganisms or skeleton metal impurities. Simultaneously, this dosage does not oxidize or destroy the active ingredients in the rust inhibitor, preventing the formation of biofilms and blockages in the spray pipes when using treated water, and ensuring that the effectiveness of the rust inhibitor in the treated water is not significantly affected.
[0025] Optionally, the pH is adjusted to 6.5-7.5 in step (1).
[0026] At this pH level, firstly, the activity of the rust inhibitor is maintained and the loss of active ingredients is reduced; secondly, it promotes the agglomeration and aggregation of large particles of impurities such as metal shavings and iron oxide.
[0027] Optionally, the modified chitosan is prepared as follows: S1: Dissolve chitosan in dilute acetic acid solution and stir until completely dissolved to obtain chitosan solution.
[0028] S2: Add salicylic acid hydroxamic acid to a solvent, add a dehydrating agent to activate the carboxyl group, and adjust the pH to 5.5-6.5 to obtain an activated salicylic acid hydroxamic acid solution; S3: Add the activated salicylic acid hydroxamic acid solution dropwise into the chitosan solution, stir the reaction at 40-60℃ for 6-8 hours, and dry to obtain intermediate A; S4: Dissolve intermediate A in an organic solvent, add trihydroxybenzoic acid and a crosslinking agent, and then treat at 50-60℃ for 4-6 hours to obtain modified chitosan.
[0029] The amino groups on chitosan undergo an amidation reaction with the carboxyl groups on activated salicylic acid, grafting the hydroxyoxime groups onto chitosan and enhancing its chelation of metal ions in wastewater. Subsequently, under the action of a crosslinking agent, the three phenolic hydroxyl groups of trihydroxybenzoic acid can serve as crosslinking points, forming a three-dimensional network structure with the chitosan molecular chain through hydrogen bonds and covalent bonds. This results in a porous network, increasing the specific surface area of the modified chitosan and making the complexation sites more easily accessible to metal ions, thereby improving the complexation rate.
[0030] Optionally, the chitosan solution has a mass fraction of 2% to 5%.
[0031] At this mass fraction, chitosan molecular chains are fully extended in the solution, and the amino and hydroxyl active sites are better exposed. If the concentration is below 2%, the chitosan molecules are too sparse, the probability of collision with salicylic acid and trihydroxybenzoic acid is reduced, the reaction rate is slow, and the grafting rate or cross-linking degree is low. If the concentration is above 5%, the chitosan molecular chains are prone to entanglement and aggregation, the active sites are encapsulated, and it is difficult for salicylic acid and trihydroxybenzoic acid to contact chitosan evenly, resulting in uneven product performance.
[0032] Optionally, the molar ratio of chitosan to salicylic acid is 1:(0.4-0.8).
[0033] At this ratio, salicylic acid can react with the active amino groups on the surface of chitosan. The system contains less free salicylic acid, resulting in higher product purity. However, if the amount of salicylic acid is too high, the hydroxyoxime and carboxyl groups in the molecule may react with the amino groups of multiple chitosan molecular chains simultaneously, leading to excessive cross-linking and affecting subsequent reactions and applications.
[0034] Optionally, the molar ratio of chitosan to trihydroxybenzoic acid is 1:(0.9-1.1).
[0035] Under this ratio, some chitosan amino groups participate in the amidation cross-linking reaction to form a porous network structure, which filters impurities in the water. At the same time, the modified chitosan also contains a large number of free amino and hydroxyl groups, and some unreacted phenolic hydroxyl and carboxyl groups of trihydroxybenzoic acid are retained, which can better complex or chelate metal ions in wastewater and reduce the metal ion content in the treated water.
[0036] Optionally, the activator in step S2 includes one of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide.
[0037] Optionally, the crosslinking agent in step S4 includes one of formaldehyde, glutaraldehyde, and succinaldehyde.
[0038] The beneficial effects of this application include, but are not limited to: 1. The water treatment method after spraying rust prevention of the retainer according to this application allows the water-based rust inhibitor to be retained in the treated water to the greatest extent. The treated water can be used in the rust prevention spraying process by supplementing some water-based rust inhibitor, thereby improving the utilization rate of water resources and water-based rust inhibitor and reducing production costs.
[0039] 2. According to the water treatment method for rust prevention after spraying the retainer as described in this application, the modified chitosan incorporates hydroxy oxime groups, phenolic hydroxyl groups, and carboxyl groups, which can effectively chelate metal ions in wastewater, thereby effectively removing Al from the wastewater. 3+ Fe 2+ Fe 3+ The rapid adsorption and removal of heavy metal ions reduces the content of heavy metal ions in wastewater and improves the quality of wastewater treatment.
[0040] 3. According to the water treatment method after spray rust prevention of the retainer in this application, the modified activated carbon contains thiol and amino groups. The thiol and amino groups have a strong affinity for heavy metal ions and work synergistically with modified chitosan to reduce the metal ion content in the wastewater, so that the treated wastewater can be used in the spray rust prevention process, thereby improving the utilization rate of water resources and water-based rust inhibitors. Detailed Implementation
[0041] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0042] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.
[0043] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.
[0044] The filter press model used in this application is not specifically limited, as long as it can achieve the filtration of wastewater. In the following embodiments and comparative examples of this application, the feed pressure of the filter press for both primary and secondary filtration is 8 kg / cm². 2 The pressing pressure is 12 kg / cm². 2 The blowing pressure is 12 kg / cm². 2 The air permeability of the filter cloth is 30 L / m. 2 / s, and the pressing time is 5 minutes.
[0045] The CAS number for activated carbon is 7440-44-0; the CAS number for diatomaceous earth is 61790-53-2; the CAS number for N-(2-aminoethyl)-3-aminopropyltriethoxysilane is 5089-72-5; the CAS number for trimethyl mercaptophosphate is 152-18-1; and the chelating resin model is SL851.
[0046] In this application, the modified chitosan treatment involves loading modified chitosan into an ion exchanger and passing the wastewater after secondary pressure filtration through the ion exchanger containing modified chitosan.
[0047] Example 1 This embodiment relates to a water treatment method after spraying a cage for rust prevention, including the following steps: (1) The pH of the wastewater generated after spraying the rust inhibitor was measured to be 10.2. 10% dilute hydrochloric acid was added to the wastewater to adjust the pH to 7.5. Then, the wastewater was filtered once by a filter press to remove larger particles of impurities. (2) The treated wastewater from step (1) is transported to a wastewater tank. Modified activated carbon is mixed with 10 times the amount of water to obtain a modified activated carbon mixture, which is then loaded into a chemical solution tank. The modified activated carbon mixture and wastewater are then transported to a mixing tank respectively, and the amount of modified activated carbon added is controlled to be 50 g / m³. 3 Then, stir in the mixing tank at a stirring speed of 60 r / min for 40 min; The modified activated carbon is prepared as follows: A1: Add activated carbon to 5 times the amount of 60wt% nitric acid solution, soak for 3 hours, filter and dry to obtain activated carbon; A2: Disperse the activated carbon in 3 times the amount of anhydrous ethanol, then add N-(2-aminoethyl)-3-aminopropyltriethoxysilane. The mass ratio of activated carbon to N-(2-aminoethyl)-3-aminopropyltriethoxysilane is 1:0.5. Stir at 60°C for 3 hours to obtain activated carbon A. A3: Activated carbon A is dispersed in anhydrous ethanol, then trimethyl mercaptophosphate is added and mixed evenly. The mass ratio of activated carbon A to trimethyl mercaptophosphate is 1:0.3. Finally, modified activated carbon is obtained by drying. (3) After the water treated in step (2) is filtered twice by a filter press, it is then treated with modified chitosan and transported to a sedimentation tank. 0.05 wt‰ sodium hypochlorite is added, and the water is left to stand in the sedimentation tank for 1 hour to obtain the treated water. The preparation method of the modified chitosan is as follows: S1: Dissolve chitosan in 5 times the amount of a 5% (w / w) dilute acetic acid solution and stir until completely dissolved to obtain a 5% (w / w) chitosan solution.
[0048] S2: Add salicylic acid to 2 times the volume of anhydrous ethanol, adjust the pH to 5.5, add 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride to activate the carboxyl group, the amount of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride added is 1.1 equivalents of the carboxyl group in salicylic acid, to obtain an activated salicylic acid solution; S3: Add the activated salicylic acid hydroxamic acid solution dropwise to the chitosan solution. The molar ratio of chitosan to salicylic acid hydroxamic acid is 1:0.4. Stir the reaction at 40°C for 8 hours. After drying, intermediate A is obtained. S4: Dissolve intermediate A in anhydrous ethanol, add trihydroxybenzoic acid and glutaraldehyde, the molar ratio of chitosan to trihydroxybenzoic acid is 1:0.9, the amount of glutaraldehyde added is 2% of the total system mass, and then treat at 50℃ for 6h to obtain modified chitosan.
[0049] Example 2 This embodiment relates to a water treatment method after spraying a cage for rust prevention, including the following steps: (1) The pH of the wastewater generated after spraying the rust inhibitor was measured to be 10.6. 10% dilute hydrochloric acid was added to the wastewater to adjust the pH to 6.5. Then, the wastewater was filtered once by a filter press to remove larger impurities in the wastewater. (2) The treated wastewater from step (1) is transported to a wastewater tank. Modified activated carbon is mixed with 10 times the amount of water to obtain a modified activated carbon mixture, which is then loaded into a chemical solution tank. The modified activated carbon mixture and wastewater are then transported to a mixing tank respectively, and the amount of modified activated carbon added is controlled to be 60 g / m³. 3 Then, stir in a mixing tank at a stirring speed of 50 r / min for 60 min; The modified activated carbon is prepared as follows: A1: Add activated carbon to 5 times the amount of 60wt% nitric acid solution, soak for 3 hours, filter and dry to obtain activated carbon; A2: Disperse the activated carbon in 3 times the amount of anhydrous ethanol, then add N-(2-aminoethyl)-3-aminopropyltriethoxysilane. The mass ratio of activated carbon to N-(2-aminoethyl)-3-aminopropyltriethoxysilane is 1:0.7. Stir at 70°C for 2 hours to obtain activated carbon A. A3: Activated carbon A is dispersed in anhydrous ethanol, then trimethyl mercaptophosphate is added and mixed evenly. The mass ratio of activated carbon A to trimethyl mercaptophosphate is 1:0.4. Finally, the modified activated carbon is obtained by drying. (3) After the water treated in step (2) is filtered twice by a filter press, it is then treated with modified chitosan and transported to a sedimentation tank. 0.1 wt‰ sodium hypochlorite is added, and the water is left to stand in the sedimentation tank for 1.5 h to obtain the treated water. The preparation method of the modified chitosan is as follows: S1: Dissolve chitosan in twice the amount of a 5% (w / w) dilute acetic acid solution and stir until completely dissolved to obtain a 2% (w / w) chitosan solution.
[0050] S2: Add salicylic acid hydroxamic acid to 2 times the amount of anhydrous ethanol, adjust the pH to 6.5, add N-hydroxysuccinimide, the amount of N-hydroxysuccinimide added is 1.1 equivalents of the carboxyl group in salicylic acid, to obtain an activated salicylic acid hydroxamic acid solution; S3: Add the activated salicylic acid hydroxamic acid solution dropwise to the chitosan solution. The molar ratio of chitosan to salicylic acid hydroxamic acid is 1:0.8. Stir the reaction at 60°C for 6 hours and dry to obtain intermediate A. S4: Dissolve intermediate A in anhydrous ethanol, add trihydroxybenzoic acid and formaldehyde, the molar ratio of chitosan to trihydroxybenzoic acid is 1:1.1, the amount of formaldehyde added is 2% of the total system mass, and then treat at 60℃ for 4h to obtain modified chitosan.
[0051] Example 3 This embodiment relates to a water treatment method after spraying a cage for rust prevention, including the following steps: (1) The pH of the wastewater generated after spraying the rust inhibitor was measured to be 10.1. 10% dilute hydrochloric acid was added to the wastewater to adjust the pH to 6. Then, the wastewater was filtered once by a filter press to remove larger impurities. (2) The treated wastewater from step (1) is transported to a wastewater tank. Modified activated carbon is mixed with 10 times the amount of water to obtain a modified activated carbon mixture, which is then loaded into a chemical solution tank. The modified activated carbon mixture and wastewater are then transported to a mixing tank respectively, and the amount of modified activated carbon added is controlled to be 55 g / m³. 3 Then, stir in the mixing tank at a stirring speed of 45 r / min for 50 min; The modified activated carbon is prepared as follows: A1: Add activated carbon to 5 times the amount of 60wt% nitric acid solution, soak for 3 hours, filter and dry to obtain activated carbon; A2: Disperse the activated carbon in 3 times the amount of anhydrous ethanol, then add N-(2-aminoethyl)-3-aminopropyltriethoxysilane. The mass ratio of activated carbon to N-(2-aminoethyl)-3-aminopropyltriethoxysilane is 1:0.6. Stir at 65°C for 2.5 h to obtain activated carbon A. A3: Activated carbon A is dispersed in anhydrous ethanol, and then trimethyl mercaptophosphate is added and mixed evenly. The mass ratio of activated carbon A to trimethyl mercaptophosphate is 1:0.35. Finally, the modified activated carbon is obtained by drying. (3) After the water treated in step (2) is filtered twice by a filter press, it is then treated with modified chitosan and transported to a sedimentation tank. 0.08 wt‰ sodium hypochlorite is added, and the water is left to stand in the sedimentation tank for 1.5 h to obtain the treated water. The preparation method of the modified chitosan is as follows: S1: Dissolve chitosan in 4 times the amount of a 5% dilute acetic acid solution and stir until completely dissolved to obtain a 4% chitosan solution.
[0052] S2: Add salicylic acid hydroxamic acid to 2 times the amount of anhydrous ethanol, adjust the pH to 6, add N-hydroxysuccinimide, the amount of N-hydroxysuccinimide added is 1.1 equivalents of the carboxyl group in salicylic acid, to obtain an activated salicylic acid hydroxamic acid solution; S3: Add the activated salicylic acid hydroxamic acid solution dropwise to the chitosan solution. The molar ratio of chitosan to salicylic acid hydroxamic acid is 1:0.6. Stir the reaction at 55°C for 7 hours. After drying, intermediate A is obtained. S4: Dissolve intermediate A in anhydrous ethanol, add trihydroxybenzoic acid and succinaldehyde, the molar ratio of chitosan to trihydroxybenzoic acid is 1:1, the amount of succinaldehyde added is 2% of the total system mass, and then treat at 55℃ for 5h to obtain modified chitosan.
[0053] Example 4 The difference between this embodiment and embodiment 3 is that the stirring speed in the stirring tank in step (2) is 20 r / min, and the rest is the same as in embodiment 3.
[0054] Example 5 The difference between this embodiment and Embodiment 3 is that the amount of modified activated carbon added is 10 g / m³. 3 The rest is the same as in Example 3.
[0055] Example 6 The difference between this embodiment and Example 3 is that the modified activated carbon is prepared by directly mixing activated carbon, N-(2-aminoethyl)-3-aminopropyltriethoxysilane and trimethylmercaptophosphate, while the rest is the same as in Example 3.
[0056] Example 7 The difference between this embodiment and Embodiment 3 is that the modified chitosan is prepared by directly mixing chitosan, salicylic acid and trihydroxybenzoic acid, while the rest is the same as in Embodiment 3.
[0057] Example 8 The difference between this embodiment and embodiment 3 is that the molar ratio of chitosan to salicylic acid in step S3 is 1:1.2, while the rest is the same as in embodiment 3.
[0058] Example 9 The difference between this embodiment and embodiment 3 is that the molar ratio of chitosan to trihydroxybenzoic acid in step S3 is 1:0.2, while the rest is the same as in embodiment 3.
[0059] Comparative Example 1 The difference between this comparative example and Example 3 is that no modified activated carbon is added, and step (2) is not performed; otherwise, it is the same as Example 3.
[0060] Comparative Example 2 The difference between this comparative example and Example 3 is that the modified activated carbon in step (2) is replaced with activated carbon, while the rest is the same as in Example 3.
[0061] Comparative Example 3 The difference between this comparative example and Example 3 is that the modified chitosan in step (3) is replaced with chitosan, and the rest is the same as in Example 3.
[0062] Comparative Example 4 The difference between this comparative example and Example 3 is that the modified chitosan in step (3) is replaced with chelating resin, while the rest is the same as in Example 3.
[0063] Comparative Example 5 The difference between this comparative example and Example 3 is that the modified chitosan preparation method in step (3) does not perform the operation of step S4, and the modified chitosan in step (3) is replaced with intermediate A obtained in step S3. The rest is the same as Example 3.
[0064] Comparative Example 6 The difference between this comparative example and Example 3 is that the salicylic acid in steps S2 and S3 of the modified chitosan preparation process in step (3) is replaced with acetic acid, while the rest is the same as in Example 3.
[0065] Test Example 1 1) COD value test: The test method refers to HJ / T399-2007; 2) Suspended solids content test: The test method is based on GB / T11901-1989; the specific test results are shown in Table 1.
[0066] Table 1
[0067] Test Example 2 (1) Stability test: 2 wt% of Tairunte 660D water-based rust inhibitor was added to the water treated in Examples 1-9 and Comparative Examples 1-6 to obtain spray liquid. The above spray liquid was placed at 60°C for 36 hours and visually inspected for stratification. If stratification occurred, it indicated that it was unstable. If no stratification occurred, it indicated that it was stable. (2) Damp heat test: Referring to the method in GB / T2361, 2 wt% of Tairunte 660D water-based rust inhibitor was added to the water obtained in Examples 1-9 and Comparative Examples 1-6 to obtain spray solution. The control spray solution was obtained by adding 4 wt% of Tairunte 660D water-based rust inhibitor to natural water. Then, the above spray solution was sprayed onto different 60*80*1mm retainer test pieces. The retainer test pieces were then suspended in a test piece rack. The temperature at the suspension point was 40℃ and the humidity inside the chamber was above 95%. The damp heat rust prevention performance test was carried out. The test was checked every 12 hours until rust appeared on the retainer test piece. The time of rust appearance was recorded. (3) Salt spray rust prevention test: Referring to the method in SH / T0081, 2 wt% of Tairunte 660D water-based rust inhibitor was added to the water obtained in Examples 1-9 and Comparative Examples 1-6 to obtain spray solutions. The blank control spray solution was obtained by adding 4 wt% of Tairunte 660D water-based rust inhibitor to tap water. Then, the above spray solutions were sprayed onto test pieces of the same material with different 60*80*1mm retainers. The test pieces were placed on the test piece placement rack in a salt spray chamber with a test salt solution concentration of 5%, a hanging temperature of 35℃, and an air saturation temperature of 50℃ to conduct salt spray rust prevention performance tests. The test pieces were checked every 8 hours until rust appeared on the test pieces. The time of rust appearance was recorded. The specific data are shown in Table 2.
[0068] Table 2
[0069] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.
Claims
1. A method for treating water after a cage spray anti-rust process, characterized in that, It comprises the following steps: (1) adding a pH regulator to the sewage produced after spraying the rust inhibitor, adjusting the pH, and then performing primary pressure filtration to remove larger impurities in the sewage; (2) conveying the treated sewage in step (1) to a sewage tank, mixing modified activated carbon with water to obtain a modified activated carbon mixture, and loading the mixture into a liquid tank, and then conveying the modified activated carbon mixture and the sewage to a stirring tank, and stirring in the stirring tank for 40-60 min; (3) conveying the water treated in step (2) through secondary pressure filtration and then through modified chitosan treatment to a sedimentation tank, adding sodium hypochlorite, and standing in the sedimentation tank for 1-1.5 h to obtain treated water; the modified chitosan is obtained by modifying salicylhydroxamic acid and trihydroxybenzoic acid.
2. The cage spray rust-preventive post-water treatment method according to claim 1, characterized by The stirring speed in the stirring tank in step (2) is 50-60 r / min.
3. The cage spray rust-preventive post-water treatment method according to claim 1, characterized by The modified activated carbon is added in an amount of 50-60 g / m 3 .
4. The cage spray rust-preventive post-water treatment method according to claim 3, characterized by The preparation method of the modified activated carbon is as follows: A1: adding activated carbon to an acidic solution, soaking, filtering and drying to obtain activated activated carbon; A2: dispersing the activated activated carbon in a solvent, then adding N-(2-aminoethyl)-3-aminopropyl triethoxysilane thereto, stirring at 60-70°C for 2-3 h to obtain activated carbon A; A3: dispersing activated carbon A in a solvent, then adding trimethyl mercaptophosphate and stirring uniformly, and finally drying to obtain modified activated carbon.
5. The cage spray rust-preventive post-water treatment method according to claim 1, characterized by The addition amount of sodium hypochlorite is 0.05-0.1 wt‰.
6. The cage spray rust-proofing post-water treatment method according to claim 1, characterized by, The pH in step (1) is adjusted to 6.5-7.
5.
7. The cage spray rust-preventive post-water treatment method according to claim 1, characterized by The preparation method of the modified chitosan is as follows: S1: dissolving chitosan in a dilute acetic acid solution, stirring until completely dissolved to obtain a chitosan solution. S2: adding salicylhydroxamic acid to a solvent, activating the carboxyl group by adding a dehydrating agent, and adjusting the pH to 5.5-6.5 to obtain an activated salicylhydroxamic acid solution; S3: dropping the activated salicylhydroxamic acid solution into the chitosan solution, stirring at 40-60°C for 6-8 h, and drying to obtain intermediate A; S4: dissolving intermediate A in an organic solvent, adding trihydroxybenzoic acid and a crosslinking agent, and then treating at 50-60°C for 4-6 h to obtain modified chitosan.
8. The cage spray rust-preventive post-water treatment method according to claim 7, characterized by The mass fraction of the chitosan solution is 2%-5%.
9. The cage spray rust-preventive post-water treatment method according to claim 7, characterized by The molar ratio of chitosan to salicylhydroxamic acid is 1:(0.4-0.8).
10. The cage spray rust-preventive post-water treatment method according to claim 7, characterized by The molar ratio of chitosan to trihydroxybenzoic acid is 1:(0.9-1.1).