Efficient defoaming agent for water treatment and preparation method thereof
By introducing dodecyl groups into silicone oil and surface modification of nanosilicon dioxide, combined with organic bentonite, the problem of insufficient foam suppression and durability of silicone defoaming agent in harsh environments is solved, and efficient and long-lasting defoaming performance is achieved, which is suitable for sewage treatment.
Patent Information
- Application Number
- CN202510388865.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2025-06-27
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing silicone defoaming agents are insufficient in harsh environments such as high temperature and extreme pH, and are prone to failure, which limits their application in sewage treatment processes.
The nanosilica is surface modified by introducing dodecyl groups into the silicone oil and using end-hydroxy polydimethylsiloxane and end-hydroxy silicone block polyether, combined with organic bentonite as a stabilizer to form a synergistic defoaming agent.
It significantly improves the foam suppression performance and durability of the defoaming agent, and can maintain stable performance under harsh conditions such as high temperature and extreme pH. It is suitable for the sewage treatment industry.
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Abstract
Description
Technical Field
[0001] The present application relates to the technical field of defoamers, and more specifically, to a high-efficiency defoamer for water treatment and a preparation method thereof. Background Art
[0002] Industrial wastewater and municipal domestic sewage are enriched with a large number of pollutants. These pollutants not only cause water eutrophication but also generate a large amount of persistent foam during the sewage treatment process. Such foam will occupy the effective space of the reactor or sedimentation tank, resulting in a significant reduction in sewage treatment efficiency. Based on the above situation, the development of efficient defoaming technology is of crucial significance for ensuring the stable operation of the water treatment system and the compliance of the effluent quality.
[0003] The mainstream defoamers in the current water treatment field include many types such as silicone defoamers, polyether defoamers, mineral oil defoamers, fatty alcohol defoamers, etc. Silicone defoamers play an important role among them. Silicone defoamers are mainly composed of polydimethylsiloxane (silicone oil) and are often formulated into emulsions or solutions with emulsifiers, solvents, etc. Under normal conditions, they have the advantages of stable chemical properties, wide application range, low volatility, non-toxicity, etc. In recent years, new silicone defoamer products have emerged in an endless stream. On the one hand, the new products have optimized the traditional process and further reduced the particle size of the defoamer. On the other hand, they have also adopted the method of compounding silicone defoamers with other additives to meet the requirements of different application scenarios.
[0004] Regarding the above technical solutions, the inventor believes that although certain progress has been made in the development of silicone defoamers, the foam suppression persistence of silicone defoamers is insufficient, and they are prone to failure in harsh environments such as high temperature and extreme pH, resulting in limited application in the sewage treatment process. Summary of the Invention
[0005] In the related art, the foam suppression persistence of silicone defoamers is insufficient, and they are prone to failure in harsh environments such as high temperature and extreme pH. In order to improve this defect, the present application provides a high-efficiency defoamer for water treatment and a preparation method thereof.
[0006] In the first aspect, the present application provides a high-efficiency defoamer for water treatment, adopting the following technical solution:
[0007] An efficient defoamer for water treatment, comprising the following components in parts by weight: 80 - 82 parts of white oil, 8 - 10 parts of silicone paste, 5 - 6 parts of emulsifier, 2.5 - 3.5 parts of polypropylene glycol, 0.8 - 1.2 parts of stabilizer; the silicone paste is compounded by silicone oil and modified silica, the side chain group of the silicone oil includes dodecyl, the modified silica is formed by dehydration condensation of a terminal hydroxyl compound and nano-silica, and the terminal hydroxyl compound includes terminal hydroxyl polydimethylsiloxane and terminal hydroxyl organosilicon block polyether; the stabilizer includes organic bentonite.
[0008] By adopting the above technical solution, in this application, dodecyl is introduced as a side chain group into the silicone oil, and nano-silica is surface-modified with terminal hydroxyl polydimethylsiloxane and terminal hydroxyl organosilicon block polyether to obtain modified silica, and bentonite is also added as a stabilizer. The dodecyl side chain can enhance the affinity between the silicone oil and the white oil, endow the white oil with good antifoaming property, and improve the defoaming and foam suppression performance of the defoamer. The polymer segments on the surface of the modified silica are intertwined with each other to form a macromolecular configuration with a spatial network structure. These macromolecular configurations make the modified silica not easy to agglomerate, and can expand the bubble volume in the foaming system, which is conducive to the rapid disappearance of foam. At the same time, these macromolecular configurations dissolve slowly in the foam system and have a certain foam suppression effect. The particles of organic bentonite can be dispersed into layered bentonite flakes under the action of high-speed shearing. These flakes can form hydrogen bonds with the modified silica, thereby forming a stable three-dimensional network structure in the foaming system, which is conducive to the stable suspension of the modified silica. Organic bentonite also has good thickening effect, can endow the foaming system with good thixotropy, increase the viscosity of the whole system, and prevent the agglomeration and sedimentation of the modified silica particles. Under the synergistic action of the above components, the defoamer of this application can have good defoaming and foam suppression performance, have remarkable defoaming persistence, and is not easy to fail even under harsh conditions such as high temperature and extreme pH, and has broad application prospects in the sewage treatment industry.
[0009] Preferably, the terminal hydroxyl organosilicon block polyether is prepared according to the following method:
[0010] Add terminal hydrogen silicone oil and allyl polyoxyethylene ether to the reaction kettle, stir and heat up to the reaction temperature. After the temperature is stable, dropwise add chloroplatinic acid catalyst into the system, and obtain terminal hydroxyl organosilicon block polyether after heat preservation reaction.
[0011] By adopting the above technical solution, the present application selects terminal hydrogen silicone oil and allyl polyoxyethylene ether as reactants, and under the catalysis of chloroplatinic acid, the hydrosilylation reaction occurs between the two, grafting the polyoxyethylene ether segment onto the silicone oil molecule to obtain terminal hydroxyl silicone block polyether. The terminal hydroxyl silicone block polyether can undergo dehydration condensation with the silanol groups on the surface of nano-silica, and can introduce polymer segments onto the surface of nano-silica, thereby obtaining modified silica.
[0012] Preferably, the reaction temperature is 118 - 123 °C.
[0013] By adopting the above technical solution, the present application optimizes the range of the reaction temperature. Within the above range, the reaction activity of the silicon-hydrogen bond is relatively high, and the reaction is relatively stable. On the one hand, it is beneficial to the full reaction of terminal hydrogen silicone oil and allyl polyoxyethylene ether, and on the other hand, it can also reduce the accumulation of by-products, thus contributing to the smooth preparation of modified silica.
[0014] Preferably, the molar ratio of the terminal hydrogen silicone oil to the allyl polyoxyethylene ether is 1:(2.25 - 2.35).
[0015] By adopting the above technical solution, the present application optimizes the proportion range of the terminal hydrogen silicone oil and the allyl polyoxyethylene ether. Within the above ratio range, after the allyl polyoxyethylene ether undergoes isomerization reaction to generate allyl glycidyl ether that is difficult to continue reacting, the remaining allyl polyoxyethylene ether can still fully react with the terminal hydrogen silicone oil, effectively controlling the influence caused by the isomerization reaction. By controlling the ratio of the reactants, the silicon-hydrogen bond in the reaction system is not easily left over, thereby reducing the influence of the isomerization product on the product stability and contributing to the smooth preparation of modified silica.
[0016] Preferably, the holding time of the reaction is 3 - 4 h.
[0017] By adopting the above technical solution, the present application optimizes the holding time range of the reaction. Within the above range, the silicon-hydrogen bond can fully participate in the reaction, thereby obtaining a terminal hydroxyl silicone block polyether with a more ideal composition, contributing to the smooth preparation of modified silica.
[0018] Preferably, the modified silica is prepared according to the following method:
[0019] (1) Add nano-silica into hexanol for ultrasonic dispersion, and then mix the obtained mixture with a terminal hydroxyl compound to obtain a raw material liquid for standby; add dibutyltin dilaurate into hexanol for ultrasonic dispersion to obtain a catalytic liquid;
[0020] (2) Mix the catalytic liquid with the raw material liquid, keep the mixture at a constant temperature for reaction, perform suction filtration after the reaction ends, wash and dry the filter cake to obtain modified silica.
[0021] By adopting the above technical solution, in the present application, under the catalytic action of dibutyltin dilaurate, nano-silica reacts with the terminal hydroxyl compound, introducing a polymer chain segment onto the surface of nano-silica, thereby obtaining modified silica.
[0022] Preferably, the silicone oil is prepared according to the following method:
[0023] Add the unsaturated monomer into the reaction vessel, introduce nitrogen to remove moisture under heating conditions, then add a platinum catalyst and a hydrogen-containing silicone oil, carry out heat preservation and stirring, and then raise the temperature for reaction. After the reaction ends, silicone oil is obtained; the unsaturated monomer includes dodecene.
[0024] By adopting the above technical solution, in the present application, a hydrosilylation reaction is carried out under the action of a platinum catalyst. Using dodecene as a reactant, a dodecyl group is introduced into the silicone oil molecule, and a silicone oil with a dodecyl group in the side chain group is obtained.
[0025] Preferably, the unsaturated monomer further includes an unsaturated fatty acid.
[0026] By adopting the above technical solution, the present application further preferably uses an unsaturated fatty acid as the unsaturated monomer. After participating in the hydrosilylation reaction, the unsaturated fatty acid can introduce carboxyl groups into the silicone oil molecule. These carboxyl groups can form hydrogen bonds with the modified silica and organic bentonite, thereby strengthening the three-dimensional network structure in the system, being beneficial to the stable suspension of the modified silica, and improving the defoaming persistence of the defoamer.
[0027] Preferably, the stabilizer further includes modified lignosulfonate, and the modified lignosulfonate is prepared according to the following method:
[0028] Stir and mix sodium lignosulfonate and sodium hydroxide solution, add aqueous chloroacetic acid solution to the mixture, then raise the temperature and continue stirring for reaction, add epichlorohydrin, and continue stirring for reaction under heating conditions. After the reaction ends, cool the obtained product to room temperature, perform suction filtration to obtain a filter cake, wash and dry the filter cake, and obtain modified lignosulfonate after grinding.
[0029] By adopting the above technical solution, the present application uses sodium lignosulfonate as a raw material, first modifies it with chloroacetic acid, and then crosslinks it with epichlorohydrin to obtain modified lignosulfonate. The carboxyl groups and sulfonic acid groups in the modified lignosulfonate can quickly adsorb onto the surface of the foam liquid film, and the rigid skeleton of the crosslinked structure can quickly spread on the liquid film surface to form a discontinuous interface. The aromatic ring of lignin and the hydrophobic regions in the crosslinked network can cooperate with the modified silica to pierce the liquid film, accelerate the drainage and rupture of the liquid film, inhibit the retention of gas and the regeneration of foam, thereby improving the defoaming and foam-inhibiting performance of the defoamer.
[0030] In a second aspect, the present application provides a preparation method for a highly efficient defoamer for water treatment, adopting the following technical solution.
[0031] A preparation method for a highly efficient defoamer for water treatment includes the following steps:
[0032] (1) Mix white oil, silicone paste, emulsifier, and polypropylene glycol, stir and heat them, and then keep them warm to obtain a pre-dispersed liquid for standby;
[0033] (2) Add a stabilizer to the pre-dispersed liquid and homogenize it to obtain a highly efficient defoamer for water treatment.
[0034] By adopting the above technical solution, the present application first pre-disperses the components except the stabilizer, and then adds the stabilizer for homogenization to obtain a highly efficient defoamer for water treatment.
[0035] In summary, the present application has the following beneficial effects:
[0036] 1. The present application introduces dodecyl as a side chain group into silicone oil, uses hydroxyl-terminated polydimethylsiloxane and hydroxyl-terminated organosilicon block polyether to modify the surface of nano-silica to obtain modified silica, and also adds bentonite as a stabilizer. Under the synergistic action of the above components, the defoamer of the present application can have good defoaming and foam-inhibiting performance, and has remarkable defoaming persistence. Even under harsh conditions such as high temperature and extreme pH, it is not easy to fail, and has broad application prospects in the sewage treatment industry.
[0037] 2. The present application introduces carboxyl groups into silicone oil molecules through unsaturated fatty acids. These carboxyl groups can form hydrogen bonds with modified silica and organic bentonite, thereby strengthening the three-dimensional network structure in the system, facilitating the stable suspension of modified silica, and improving the defoaming persistence of the defoamer.
[0038] 3. The present application prepared modified lignosulfonate. The carboxyl groups and sulfonic acid groups in the modified lignosulfonate can be rapidly adsorbed onto the surface of the foam liquid film, and the rigid framework of the cross-linked structure can rapidly spread on the liquid film surface to form a discontinuous interface. The aromatic rings of lignin and the hydrophobic regions in the cross-linked network can cooperate with the modified silica to pierce the liquid film, accelerating the drainage and rupture of the liquid film, inhibiting the retention of gas and the regeneration of foam, thereby improving the defoaming and foam suppression performance of the defoamer. Detailed Embodiments
[0039] The present application will be further described in detail below with reference to Examples, Preparation Examples and Comparative Examples. The raw materials involved in the present application can all be obtained commercially.
[0040] Preparation Example of Modified Silica
[0041] The following takes Preparation Example 1 as an example for illustration.
[0042] Preparation Example 1
[0043] In this preparation example, the hydroxyl-terminated compound is composed of hydroxyl-terminated polydimethylsiloxane and hydroxyl-terminated organosilicon block polyether. The hydroxyl-terminated organosilicon block polyether is prepared according to the following method:
[0044] Hydrogen-terminated silicone oil (the hydrogen in the Si-H group accounts for 0.08% of the total weight of the hydrogen-containing silicone oil) and allyl polyoxyethylene ether (average molecular weight is 500) with a molar ratio of 1:2 were added to the reaction kettle, and the temperature was raised to 115 °C with stirring. After the temperature was stabilized, chloroplatinic acid catalyst was added dropwise to the system at a dosage of 2 g / kg (based on the total weight of the reactants), and the reaction was carried out at a constant temperature for 2.5 h to obtain the hydroxyl-terminated organosilicon block polyether.
[0045] In this preparation example, the modified silica was prepared according to the following method:
[0046] (1) 300 g of nano-silica was added to 2500 mL of hexanol and ultrasonically dispersed for 20 min, and then the obtained mixture was mixed with 150 g of the hydroxyl-terminated compound and stirred at a rate of 200 r / min for 24 h to obtain a raw material liquid for standby; 8 g of dibutyltin dilaurate was added to 1000 mL of hexanol and ultrasonically dispersed to obtain a catalytic liquid;
[0047] (2) The catalytic liquid and the raw material liquid were mixed and stirred for 30 min, during which the reaction was carried out at a constant temperature. After the reaction was completed, suction filtration was carried out, and the filter cake was washed and dried to obtain the modified silica.
[0048] Preparation Example 2
[0049] The difference between this preparation example and Preparation Example 1 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the reaction temperature is 118 °C.
[0050] Preparation Example 3
[0051] The difference between this preparation example and Preparation Example 1 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the reaction temperature is 121 °C.
[0052] Preparation Example 4
[0053] The difference between this preparation example and Preparation Example 1 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the reaction temperature is 123 °C.
[0054] Preparation Example 5
[0055] The difference between this preparation example and Preparation Example 4 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the weight ratio of the hydrogen-terminated silicone oil to the allyl polyoxyethylene ether is 1:2.25.
[0056] Preparation Example 6
[0057] The difference between this preparation example and Preparation Example 4 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the weight ratio of the hydrogen-terminated silicone oil to the allyl polyoxyethylene ether is 1:2.30.
[0058] Preparation Example 7
[0059] The difference between this preparation example and Preparation Example 4 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the weight ratio of the hydrogen-terminated silicone oil to the allyl polyoxyethylene ether is 1:2.35.
[0060] Preparation Example 8
[0061] The difference between this preparation example and Preparation Example 4 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the reaction time is 3 h.
[0062] Preparation Example 9
[0063] The difference between this preparation example and Preparation Example 4 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the reaction time is 3.5 h.
[0064] Preparation Example 10
[0065] The difference between this preparation example and Preparation Example 4 is that in the method for preparing the hydroxyl-terminated organosilicon block polyether, the reaction time is 4 h.
[0066] Preparation Example of Silicone Oil
[0067] Taking Preparation Example 11 as an example, it is illustrated as follows.
[0068] Preparation Example 11
[0069] In this preparation example, the unsaturated monomer is dodecene, the molar ratio of the hydrogen atoms of the Si-H bond in the hydrogen-containing silicone oil to the double bond in the unsaturated monomer is 1:1.2, the catalyst is platinum catalyst PT-5000, and the catalyst dosage is 3.5 ppm.
[0070] In this preparation example, the silicone oil is prepared according to the following method:
[0071] Add the unsaturated monomer into the reaction vessel, purge the moisture by introducing nitrogen under the heating condition of 90 °C, then add the platinum catalyst and the hydrogen-containing silicone oil (hydrogen content 0.18%), after 1 h of heat preservation and stirring, raise the temperature to 120 °C and continue the reaction for 2 h, and obtain the silicone oil after the reaction ends.
[0072] Preparation Example 12
[0073] The difference between this preparation example and Preparation Example 11 is that the unsaturated monomer is a mixture of dodecene and oleic acid in a weight ratio of 8:1.
[0074] Preparation Example of Modified Lignosulfonate
[0075] The following takes Preparation Example 13 as an example for illustration.
[0076] Preparation Example 13
[0077] In this preparation example, the modified lignosulfonate is prepared according to the following method:
[0078] Stir and mix 4 g of sodium lignosulfonate and 8 mL of sodium hydroxide solution with a concentration of 2 mol / L, add 3 mL of aqueous solution of chloroacetic acid with a concentration of 20 wt% to the mixture, then raise the temperature to 55 °C and continue stirring and reacting for 3 h, cool down to 50 °C and add 6 mL of epichlorohydrin, continue stirring and reacting for 6 h under the heating condition of 55 °C, after the reaction ends, cool the obtained product to room temperature, filter by suction to obtain a filter cake, wash the filter cake with water and dry it, and pass through a 200-mesh sieve after grinding to obtain the modified lignosulfonate.
[0079] Examples
[0080] Examples 1-5
[0081] The following takes Example 1 as an example for illustration.
[0082] Example 1
[0083] In this example, the white oil is 26# white oil, the silicone paste is compounded from the silicone oil of Preparation Example 11 and the modified silica of Preparation Example 1 in a weight ratio of 19:1, the emulsifier is a mixture of Span 80 and Tween 80 in a weight ratio of 5:1, the polypropylene glycol is PPG800, and the stabilizer is organic bentonite SD-1.
[0084] This embodiment provides a highly efficient defoamer for water treatment, which comprises the following components in parts by weight: 80 g of white oil, 8 g of silicone paste, 5 g of emulsifier, 2.5 g of polypropylene glycol, and 0.8 g of stabilizer;
[0085] This embodiment provides a preparation method of a highly efficient defoamer for water treatment, which comprises the following steps:
[0086] (1) Mix white oil, silicone paste, emulsifier and polypropylene glycol, stir and heat at a rate of 450 r / min under the condition of oil bath heating at 110 °C for 15 min, and then keep warm to obtain a pre-dispersed liquid for standby;
[0087] (2) Add a stabilizer to the pre-dispersed liquid, and homogenize it at 14000 rpm for 5 min to obtain a highly efficient defoamer for water treatment.
[0088] As shown in Table 1, the main difference between Examples 1-5 lies in the different raw material ratios of the defoamer.
[0089] Table 1 Raw material ratios of the defoamer
[0090] Sample Example 1 Example 2 Example 3 Example 4 Example 5 White oil / g 80 80.5 81 81.5 82 Silicone paste / g 8 8.5 9 9.5 10 Emulsifier / g 5 5.2 5.5 5.8 6 Polypropylene glycol / g 2.5 2.8 3 3.2 3.5 Stabilizer / g 0.8 0.9 1.0 1.1 1.2
[0091] Examples 5-14
[0092] As shown in Table 2, the difference between Examples 5-14 is that the preparation examples of modified silica are different.
[0093] Table 2 Preparation examples of modified silica
[0094] Sample Preparation Example Example 5 Preparation Example 1 Example 6 Preparation Example 2 Example 7 Preparation Example 3 Example 8 Preparation Example 4 Example 9 Preparation Example 5 Example 10 Preparation Example 6 Example 11 Preparation Example 7 Example 12 Preparation Example 8 Example 13 Preparation Example 9 Example 14 Preparation Example 10
[0095] Example 15
[0096] The difference between this example and Example 14 is that the silicone oil is prepared according to the method of Preparation Example 12.
[0097] Example 16
[0098] The difference between this example and Example 15 is that the stabilizer further includes modified lignosulfonate, and the weight ratio of modified lignosulfonate to organic bentonite is 1:3. The modified lignosulfonate is prepared according to the method of Preparation Example 13.
[0099] Comparative example
[0100] Comparative example 1
[0101] This comparative example selects the Datian AT-140 silicone defoamer with a solid content of 10% as a control.
[0102] Comparative example 2
[0103] The difference between this comparative example and Example 1 is that the components of the silicone defoamer do not include a stabilizer.
[0104] Comparative Example 3
[0105] The difference between this comparative example and Example 1 is that the silicone oil is replaced with dimethyl silicone oil (Dow Corning PMX-200).
[0106] Comparative Example 4
[0107] The difference between this comparative example and Example 1 is that the modified silica is replaced with fumed nano-silica (HB-620).
[0108] Performance testing method
[0109] Paper-making chemical sewage was selected as the test object. Before the formal test, the blank foaming time of the paper-making chemical sewage was first tested, and the result was 15 s.
[0110] 600 mL of sewage was added to the circulating bubbling pump and heated to 75 °C. The circulating pump was turned on. When the foam height reached 300 mL, 0.2 mL of defoamer (composition) was added, and the timing was started. The foam height was recorded according to the time. When the foam reached 300 mL again, the timing was stopped. The measured time was recorded as the foam suppression time T. Based on the T of Comparative Example 1, the ratio between the T values of each example and comparative example and the T value of Comparative Example 1 was calculated. This ratio was recorded as the relative foam suppression time, and the lowest value of the foam height measured after adding the defoamer (composition) was recorded as the lowest foam height. The test results of the relative foam suppression time and the lowest foam height are shown in Table 3.
[0111] Table 3 Detection results
[0112]
[0113] Combined with Examples 1-5 and Comparative Example 1 and Table 3, it can be seen that the foam suppression time measured in Examples 1-5 is nearly twice that of Comparative Example 1, and the lowest foam height is significantly smaller than that of Comparative Example 1. This is because the dodecyl side chain in the silicone oil molecule endows the white oil with good anti-foaming properties. The polymer chain segments on the surface of the modified silica reduce the agglomeration phenomenon, promote the rapid disappearance of the foam, and have a certain foam suppression effect. The layered bentonite flakes generated by the organobentonite are associated with the modified silica through hydrogen bonds. At the same time, the organobentonite also plays a certain thickening role, preventing the agglomeration and sedimentation of the modified silica particles. Under the synergistic effect of the above components, the defoamer of the present application can have good defoaming and foam suppression performance and remarkable defoaming persistence.
[0114] Combined with Example 1 and Comparative Example 2 and with reference to Table 3, it can be seen that the defoaming time of Comparative Example 2 is shorter, and the height of the lowest point of the foam is larger. This is because in Comparative Example 2, organophilic bentonite cannot hinder the agglomeration and sedimentation of modified silica, resulting in a certain impact on the defoaming and antifoaming performance.
[0115] Combined with Example 1 and Comparative Example 3 and with reference to Table 3, it can be seen that the defoaming time of Comparative Example 3 is shorter, and the height of the lowest point of the foam is larger. This is because the silicone oil molecules in Comparative Example 3 lack long-chain alkyl groups, so the compatibility between silicone oil and white oil is poor, and the ideal antifoaming performance cannot be exerted. Therefore, the overall defoaming and antifoaming performance of the defoamer is poor.
[0116] Combined with Example 1 and Comparative Example 4 and with reference to Table 3, it can be seen that the defoaming time of Comparative Example 4 is shorter, and the height of the lowest point of the foam is larger. This is because the surface of the fumed silica in Comparative Example 4 lacks organic segments and cannot effectively hinder particle agglomeration, resulting in a greater impact on the overall defoaming and antifoaming performance of the defoamer.
[0117] Combined with Examples 5 - 14 and with reference to Table 3, it can be seen that in the method for preparing terminal hydroxyl silicone block polyether, when the reaction temperature is 118 - 123 °C, the molar ratio of terminal hydrogen silicone oil to allyl polyoxyethylene ether is 1:(2.25 - 2.35), and the holding reaction time is 3 - 4 h, since the hydrosilylation reaction can proceed sufficiently and is less interfered by isomerization products, the prepared terminal hydroxyl silicone block polyether can fully modify the silica, thereby improving the overall defoaming and antifoaming performance of the defoamer.
[0118] Combined with Example 14 and Example 15 and with reference to Table 3, it can be seen that the defoaming time measured in Example 15 is longer. This is because after unsaturated fatty acids participate in the hydrosilylation reaction, carboxyl groups can be introduced into the silicone oil molecules. These carboxyl groups can form hydrogen bonds with modified silica and organophilic bentonite, thereby strengthening the three-dimensional network structure in the system, facilitating the stable suspension of modified silica, and improving the defoaming persistence of the defoamer.
[0119] Combined with Example 15 and Example 16 and with reference to Table 3, it can be seen that the defoaming time measured in Example 16 is longer, and the height of the lowest point of the foam is smaller. This is because the carboxyl groups and sulfonic acid groups in the modified lignosulfonate can quickly adsorb onto the surface of the foam liquid film, and the rigid skeleton of the cross-linked structure can quickly spread on the liquid film surface to form a discontinuous interface. The aromatic rings of lignin and the hydrophobic regions in the cross-linked network can cooperate with the modified silica to pierce the liquid film, accelerating the drainage and rupture of the liquid film, inhibiting the retention of gas and the regeneration of foam, thereby improving the defoaming and antifoaming performance of the defoamer.
[0120] The above embodiments are merely explanations of the present application and not limitations thereof. After reading this specification, those skilled in the art may make modifications to the embodiments of the present application that do not contribute creatively, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.
Claims
1. A high-efficiency defoamer for water treatment, characterized in that: The invention comprises the following components in parts by weight: 80-82 parts of white oil, 8-10 parts of silicone paste, 5-6 parts of emulsifier, 2.5-3.5 parts of polypropylene glycol and 0.8-1.2 parts of stabilizer; the silicone paste is compounded by silicone oil and modified silicon dioxide, the side chain group of the silicone oil comprises dodecyl group, the modified silicon dioxide is formed by dehydration condensation of terminal hydroxyl compound and nano silicon dioxide, the terminal hydroxyl compound comprises terminal hydroxyl polydimethylsiloxane and terminal hydroxyl organosilicon block polyether; the stabilizer comprises organic bentonite.
2. The high-efficiency defoamer for water treatment according to claim 1, characterized in that The hydroxyl-terminated organosilicon block polyether is prepared according to the following method: Add terminal hydrogen silicone oil and allyl polyoxyethylene ether into the reaction kettle, stir and heat to the reaction temperature, after the temperature is stable, add chloroplatinic acid catalyst dropwise into the system, and obtain terminal hydroxyl silicone block polyether after heat preservation reaction.
3. The high-efficiency defoamer for water treatment according to claim 2, characterized in that: The reaction temperature is 118-123°C.
4. The high-efficiency defoamer for water treatment according to claim 3, characterized in that: The molar ratio of the terminal hydrogen silicone oil to the allyl polyoxyethylene ether is 1:(2.25-2.35).
5. The high-efficiency defoamer for water treatment according to claim 4, characterized in that: The insulation reaction time is 3-4h.
6. The high-efficiency defoamer for water treatment according to claim 2, characterized in that: The modified silicon dioxide is prepared according to the following method: (1) adding nano-silicon dioxide to hexanol for ultrasonic dispersion, and then mixing the obtained mixture with a terminal hydroxyl compound to obtain a raw material liquid for standby use; adding dibutyltin dilaurate to hexanol for ultrasonic dispersion to obtain a catalyst liquid; (2) The catalyst liquid and the raw material liquid are mixed and then kept warm for reaction. After the reaction is completed, the mixture is filtered and the filter cake is washed and dried to obtain modified silica.
7. The high-efficiency defoamer for water treatment according to claim 1, characterized in that: The silicone oil is prepared as follows: The unsaturated monomer is added into a reaction container, nitrogen is introduced under heating conditions to drive out moisture, and then a platinum catalyst and hydrogen-containing silicone oil are added. After heat preservation and stirring, the temperature is raised to react, and silicone oil is obtained after the reaction is completed; the unsaturated monomer includes dodecene.
8. The high-efficiency defoamer for water treatment according to claim 7, characterized in that: The unsaturated monomers also include unsaturated fatty acids.
9. The high-efficiency defoamer for water treatment according to claim 8, characterized in that: The stabilizer also includes modified lignin sulfonate, and the modified lignin sulfonate is prepared according to the following method: Sodium lignin sulfonate and sodium hydroxide solution are stirred and mixed, chloroacetic acid aqueous solution is added to the mixture, then the temperature is increased and stirring reaction is continued, epichlorohydrin is added, stirring reaction is continued under heating conditions, after the reaction is completed, the obtained product is cooled to room temperature, filtered to obtain a filter cake, the filter cake is washed and dried, and ground to obtain modified lignin sulfonate.
10. The method for preparing a high-efficiency defoaming agent for water treatment according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) white oil, silicone paste, emulsifier and polypropylene glycol are mixed, stirred and heated, and then kept warm to obtain a pre-dispersed liquid for later use; (2) Add a stabilizer to the pre-dispersion liquid and obtain a high-efficiency defoaming agent for water treatment after homogenization.