A silicone composite solid defoaming agent for space station water treatment and a preparation method thereof

Abstract

The application discloses a kind of space station water treatment with organic silicon composite solid defoamer and preparation method thereof, it is related to defoamer technical field.The space station water treatment with organic silicon composite solid defoamer includes the following weight parts of raw materials: polydimethylsiloxane 25-35 parts, water-soluble silicone oil 5-10 parts, white carbon black 10-15 parts, emulsifier 3-5 parts, dispersing agent 3-4 parts, carrier 25-35 parts.The intermediate 1 is generated by the reaction of 1H,1H-perfluorohexylamine and epichlorohydrin, the intermediate 1 is reacted with dodecylamine to generate intermediate 2, and the emulsifier is obtained by the reaction of intermediate 2 and amino-polyethylene glycol-carboxyl.The space station water treatment with organic silicon composite solid defoamer prepared by the application has excellent defoaming, bubble suppressing performance and good water dispersibility.

Description

Technical Field

[0001] This invention relates to the field of defoamer technology, specifically to an organosilicon composite solid defoamer for water treatment in space stations and its preparation method. Background Technology

[0002] As a closed-space life support system for astronauts' long-term stays, the manned space station relies heavily on water recycling for survival and mission continuity. Wastewater such as urine and condensate requires multi-step purification processes (e.g., distillation, membrane separation, adsorption) for efficient water recovery. However, these processes are prone to generating significant foam due to mechanical agitation, gas release (e.g., ammonia, carbon dioxide), and high organic concentrations (e.g., urea, protein). In microgravity, the lack of a gravity-driven natural foam breakage mechanism leads to serious problems such as decreased water treatment efficiency, water quality safety risks, and wasted space resources. Therefore, the space station water treatment system places higher demands on the defoaming and foam-suppressing performance of defoamers, requiring more efficient agents. Currently, traditional solid defoamers often use a mixture of single organosilicon compounds and inert carriers, resulting in uneven dispersion, rapid release of active ingredients, and weak resistance to extreme environments. Furthermore, commonly used liquid defoamers tend to float and stratify under microgravity, making uniform dispersion difficult and limiting their application in the space station environment.

[0003] Chinese invention patent CN103028275A discloses a method for preparing a solid silicone defoamer. This solid defoamer is a compound defoamer composed of various silicone defoaming actives, emulsifying agents, surface modifiers, and a carrier. The silicone defoaming actives include methyl silicone oil, polyether-modified silicone oil, dimethylsiloxane hydrolysate, and silica. The emulsifying agent is a nonionic surfactant, selected from one or more of alkylphenol polyoxyethylene ether, polyoxyethylene ether, and fatty alcohol polyoxyethylene ether. The surface modifiers are triethanolamine and n-octanol. The carrier is sodium carbonate or sodium bicarbonate. This solid defoamer exhibits good defoaming and foam-suppressing properties, but its water dispersibility is still insufficient. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide an organosilicon composite solid defoamer for water treatment in space stations and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An organosilicon composite solid defoamer for water treatment in space stations comprises the following raw materials in parts by weight:

[0007] 25-35 parts of polydimethylsiloxane, 5-10 parts of water-soluble silicone oil, 10-15 parts of silica, 3-5 parts of emulsifier, 3-4 parts of dispersant, and 25-35 parts of carrier;

[0008] The emulsifier is prepared by the following method:

[0009] S1: 1H,1H-perfluorohexylamine reacts with epichlorohydrin to produce intermediate 1; the reaction equation is shown below:

[0010]

[0011] S2: Intermediate 1 reacts with dodecylamine to form intermediate 2; the reaction equation is shown below:

[0012]

[0013] S3: Intermediate 2 reacts with amino-polyethylene glycol-carboxyl groups to form an emulsifier; the reaction equation is shown below.

[0014]

[0015] In step S1, the molar ratio of 1H,1H-perfluorohexylamine to epichlorohydrin is 1:(1.1-1.2).

[0016] In step S2, the molar ratio of intermediate 1 to dodecylamine is 1:(1.1-1.3).

[0017] In step S3, the mass ratio of intermediate 2 to amino-polyethylene glycol-carboxyl group is 1:(4.1-4.8).

[0018] The dispersant is prepared by the following method:

[0019] N1: Tricarboxylic acid reacts with 3-glycidyl etheroxypropyltriethoxysilane to give intermediate A; the reaction equation is shown below.

[0020]

[0021] N2: Intermediate A reacts with 4'-carboxybenzo-15-crown 5-ether to yield a dispersant; the reaction equation is shown below.

[0022]

[0023] In step N1, the molar ratio of the tricarboxylic acid to 3-glycidyl etheroxypropyltriethoxysilane is 1:(3.1-3.2).

[0024] In step N2, the molar ratio of intermediate A to 4'-carboxybenzo-15-crown 5-ether is 1:(3.1-3.2).

[0025] The reaction temperature in step N1 is 55-65℃, and the reaction time is 4-6h.

[0026] The reaction temperature for step N2 is 25-30℃, and the reaction time is 7-9h.

[0027] The silica is a hydrophobic silica.

[0028] The carrier is diatomaceous earth.

[0029] A method for preparing an organosilicon composite solid defoamer for water treatment in a space station includes the following steps:

[0030] (1) Weigh out the following by weight: 25-35 parts of polydimethylsiloxane, 5-10 parts of water-soluble silicone oil, 10-15 parts of silica, 3-5 parts of emulsifier, 3-4 parts of dispersant, and 25-35 parts of carrier;

[0031] (2) Add polydimethylsiloxane, water-soluble silicone oil and fumed silica to a mixer, heat and stir to mix, cool down and add emulsifier and dispersant, stir and mix, add carrier and stir to mix to obtain a mixture, and dry, crush and sieve the mixture to obtain organosilicon composite solid defoamer for space station water treatment.

[0032] Due to the adoption of the above technical solutions, the beneficial effects of the present invention include:

[0033] The organosilicon composite solid defoamer prepared by this invention exhibits excellent defoaming and foam-suppressing properties, as well as good water dispersion stability. The emulsifier added to the solid defoamer achieves a hydrophilic-hydrophobic balance through the hydrophilic long-chain, long alkyl chain, and fluorocarbon chain hydrophobic structure of polyethylene glycol, enhancing the excellent defoaming and foam-suppressing performance in microgravity environments. The dispersant added to the solid defoamer has a multi-branched structure, forming a three-dimensional barrier on the surface of the defoamer particles, inhibiting random particle collision and aggregation. The siloxane unit can form chemical / physical adsorption with the hydrophobic core of polydimethylsiloxane in the defoamer through Si-O bonds. The macrocyclic structure of the crown ether can capture electrolyte ions in water, forming an ion hydration layer, achieving bidirectional stability of particle anchoring and aqueous phase dispersion. This avoids pipeline blockage caused by particle sedimentation or floating, and can adapt to the high-salt environment of urine processors. It can achieve dispersion-release-defoaming under microgravity conditions, and has significant application value in space station water treatment. Detailed Implementation

[0034] The following description, in conjunction with specific embodiments, provides further details, but the present invention is not limited to these embodiments.

[0035] Example 1: Preparation of emulsifier:

[0036] S1: Under nitrogen protection, 0.1 mol of 1H,1H-perfluorohexylamine, 0.11 mol of epichlorohydrin, and 6 mmol of tetrabutylammonium bromide were added to 200 ml of DMF. The mixture was stirred and stirred until homogeneous. The reaction was carried out at 80 °C for 5 h. The temperature was lowered to 65 °C, and 8 g of 20 wt% sodium hydroxide solution was slowly added dropwise over 30 min. The mixture was then cooled to room temperature and the reaction was continued for 12 h. The mixture was then distilled under reduced pressure at 80 °C for 2 h. 200 ml of ice water was added to precipitate the solid. The solid was filtered, washed with deionized water (3 × 100 ml), and dried under vacuum at 70 °C for 10 h to obtain intermediate 1. Its 1H NMR data are as follows: 1 H NMR (300 MHz, DMSO- d 6)) δ 4.56 (t, J = 0.6 Hz, 1H), 3.61 (s, 1H), 3.57(dd, J = 3.0, 0.5 Hz, 2H), 2.99-2.82 (m, 2H), 2.81-2.65 (m, 2H);

[0037] S2: Under nitrogen protection, 0.11 mol of dodecylamine was added to 300 ml of toluene and stirred until homogeneous. Then, 0.1 mol of intermediate 1 was added in three batches (20 min apart), followed by 0.1 mol of triethylamine. The mixture was heated to 80 °C and reacted for 6 h. After cooling to room temperature, the mixture was washed with saturated sodium chloride solution (3 × 100 ml), dried over 20 g of anhydrous sodium sulfate, filtered, rotary evaporated at 70 °C for 2 h, and then vacuum dried at 70 °C for 5 h to obtain intermediate 2. Its 1H NMR data are as follows: 1 H NMR (300 MHz, DMSO- d 6) δ 4.51 (d, J = 5.0 Hz,1H), 4.27 (t, J = 0.6 Hz, 1H), 3.66 (d, J = 5.0 Hz, 1H), 3.53 (d, J = 1.3 Hz,2H), 2.74-2.62 (m, 6H), 2.62-2.59 (m, 1H), 1.55-1.38 (m, 2H), 1.35-1.24 (m,18H), 0.89 (s, 3H);

[0038] S3: Under nitrogen protection, add 10g of intermediate 2, 41g of amino-polyethylene glycol-carboxyl (number average molecular weight of 2000) and 0.5g of p-toluenesulfonic acid to 300ml of toluene, stir and mix well, heat to 100℃, and react for 12h (during which water produced in the reaction is separated by a water separator), cool to room temperature, adjust the pH to neutral with saturated sodium bicarbonate solution, separate the layers, distill under reduced pressure at 60℃ for 3h, add 400ml of n-hexane and stir to precipitate the precipitate, filter, and dry under vacuum at 60℃ for 12h to obtain the emulsifier.

[0039] Example 2: Preparation of emulsifier:

[0040] S1: Under nitrogen protection, 0.1 mol of 1H,1H-perfluorohexylamine, 0.115 mol of epichlorohydrin and 6 mmol of tetrabutylammonium bromide were added to 200 ml of DMF. The mixture was stirred and stirred until homogeneous. The reaction was carried out at 85 °C for 4 h. The temperature was lowered to 65 °C, and 8 g of 20 wt% sodium hydroxide solution was slowly added dropwise over 30 min. The mixture was cooled to room temperature and the reaction was continued for 12 h. The mixture was then distilled under reduced pressure at 80 °C for 2 h. 200 ml of ice water was added to precipitate the solid. The solid was filtered, washed with deionized water (3 × 100 ml), and dried under vacuum at 70 °C for 10 h to obtain intermediate 1.

[0041] S2: Under nitrogen protection, 0.12 mol of dodecylamine was added to 300 ml of toluene and stirred until well mixed. 0.1 mol of intermediate 1 was added in 3 batches (20 min apart). 0.1 mol of triethylamine was added, and the mixture was heated to 80 °C and reacted for 6 h. After cooling to room temperature, the mixture was washed with saturated sodium chloride solution (3 × 100 ml), dried with 20 g of anhydrous sodium sulfate, filtered, rotary evaporated at 70 °C for 2 h, and vacuum dried at 70 °C for 5 h to obtain intermediate 2.

[0042] S3: Under nitrogen protection, add 10g of intermediate 2, 44g of amino-polyethylene glycol-carboxyl (number average molecular weight of 2000) and 0.5g of p-toluenesulfonic acid to 300ml of toluene, stir and mix well, heat to 105℃, and react for 11h (during which water produced in the reaction is separated by a water separator), cool to room temperature, adjust the pH to neutral with saturated sodium bicarbonate solution, separate the layers, distill under reduced pressure at 60℃ for 3h, add 400ml of n-hexane and stir to precipitate the precipitate, filter, and dry under vacuum at 60℃ for 12h to obtain the emulsifier.

[0043] Example 3: Preparation of emulsifier:

[0044] S1: Under nitrogen protection, 0.1 mol of 1H,1H-perfluorohexylamine, 0.12 mol of epichlorohydrin and 6 mmol of tetrabutylammonium bromide were added to 200 ml of DMF. The mixture was stirred and stirred until homogeneous. The reaction was carried out at 90 °C for 3 h. The temperature was lowered to 65 °C, and 8 g of 20 wt% sodium hydroxide solution was slowly added dropwise over 30 min. The mixture was cooled to room temperature and the reaction was continued for 12 h. The mixture was then distilled under reduced pressure at 80 °C for 2 h. 200 ml of ice water was added to precipitate the solid. The solid was filtered, washed with deionized water (3 × 100 ml), and dried under vacuum at 70 °C for 10 h to obtain intermediate 1.

[0045] S2: Under nitrogen protection, 0.13 mol of dodecylamine was added to 300 ml of toluene and stirred until well mixed. 0.1 mol of intermediate 1 was added in 3 batches (20 min apart). 0.1 mol of triethylamine was added, and the mixture was heated to 85 °C and reacted for 6 h. After cooling to room temperature, the mixture was washed with saturated sodium chloride solution (3 × 100 ml), dried with 20 g of anhydrous sodium sulfate, filtered, rotary evaporated at 70 °C for 2 h, and vacuum dried at 70 °C for 5 h to obtain intermediate 2.

[0046] S3: Under nitrogen protection, add 10g of intermediate 2, 48g of amino-polyethylene glycol-carboxyl (number average molecular weight of 2000) and 0.5g of p-toluenesulfonic acid to 300ml of toluene, stir and mix well, heat to 110℃, and react for 10h (during which water produced by the reaction is separated by a water separator), cool to room temperature, adjust the pH to neutral with saturated sodium bicarbonate solution, separate the layers, distill under reduced pressure at 60℃ for 3h, add 400ml of n-hexane and stir to precipitate the precipitate, filter, and dry under vacuum at 60℃ for 12h to obtain the emulsifier.

[0047] Example 4: Preparation of dispersant:

[0048] N1: Under nitrogen protection, 0.1 mol of tricarboxylic acid was added to 100 mL of anhydrous toluene and stirred until well mixed. Then, 400 mL of anhydrous toluene solution containing 0.31 mol of 3-glycidyl etheroxypropyltriethoxysilane was slowly added dropwise over 1 hour. Next, 0.305 mol of triethylamine was added, and the mixture was heated to 55 °C and reacted for 6 hours. After cooling to room temperature, the mixture was distilled under reduced pressure at 70 °C for 2 hours. 600 mL of anhydrous n-hexane was added and stirred to precipitate the precipitate. The precipitate was filtered, washed with cold anhydrous n-hexane (3 × 100 mL), and dried under vacuum at 60 °C for 8 hours to obtain intermediate A. Its 1H NMR data are as follows: 1 H NMR (300 MHz, DMSO- d 6) δ 5.09 (d, J = 5.0 Hz, 3H), 4.17-4.00 (m, 6H), 3.89 (t, J = 4.9 Hz, 3H), 3.59 (d, J = 2.0 Hz, 18H), 3.58-3.37 (m, 12H), 3.36 (s, 1H), 2.82-2.51 (m, 4H), 1.69 (s, 6H), 1.28 (d, J =12.4 Hz, 6H), 1.20 (s, 27H);

[0049] N2: Under nitrogen protection, 600 ml of anhydrous DMF and 0.31 mol of 4'-carboxybenzo-15-crown 5-ether were stirred and mixed. Then, 0.31 mol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.31 mol of... N-hydroxysuccinimide and 0.31 mol of triethylamine were mixed and added in five equal batches (5 min apart) to a DMF solution of 4'-carboxybenzo-15-crown 5-ether. The mixture was activated by stirring in an ice bath for 45 min. 0.1 mol of intermediate A was added to 500 mL of anhydrous DMF and stirred until homogeneous. The activated 4'-carboxybenzo-15-crown 5-ether DMF solution was slowly added dropwise over 1 h. The reaction was carried out at 25 °C for 9 h, followed by vacuum distillation at 70 °C for 3 h. 2000 mL of anhydrous cold diethyl ether was added to precipitate the precipitate. The precipitate was filtered, washed with anhydrous diethyl ether (3 × 100 mL), and dried under vacuum at 60 °C for 8 h to obtain the dispersant. Its 1H NMR data are as follows: 1 H NMR (300 MHz, DMSO- d 6) δ 7.65 (dd, J = 7.5, 2.0 Hz, 3H), 7.34 (d, J = 2.0 Hz, 3H), 6.89 (d, J = 7.5 Hz, 3H), 4.95 (d, J = 3.7 Hz, 3H), 4.38-4.27 (m, 6H), 4.17 (d, J = 1.0 Hz, 12H), 3.84-3.67 (m, 18H), 3.66-3.55(m, 42H), 3.50 (d, J = 10.0 Hz, 6H), 3.35 (s, 1H), 2.77 (d, J = 12.4 Hz, 4H),1.69 (s, 6H), 1.28 (d, J = 12.4 Hz, 6H), 1.20 (s, 27H).

[0050] Example 5: Preparation of dispersant:

[0051] N1: Under nitrogen protection, 0.1 mol of tricarboxylic acid was added to 100 ml of anhydrous toluene and stirred until well mixed. Then, 400 ml of anhydrous toluene solution containing 0.315 mol of 3-glycidyl etheroxypropyltriethoxysilane was slowly added dropwise over 1 hour. 0.305 mol of triethylamine was added, and the mixture was heated to 60 °C and reacted for 5 hours. The mixture was then cooled to room temperature and distilled under reduced pressure at 70 °C for 2 hours. 600 ml of anhydrous n-hexane was added and stirred to precipitate the precipitate. The precipitate was filtered, washed with cold anhydrous n-hexane (3 × 100 ml), and dried under vacuum at 60 °C for 8 hours to obtain intermediate A.

[0052] Under nitrogen protection, 600 ml of anhydrous DMF and 0.315 mol of 4'-carboxybenzo-15-crown 5-ether were stirred and mixed thoroughly. Then, 0.315 mol of 1-ethyl-(3-dimethylaminopropyl)carbonyldiimide hydrochloride and 0.315 mol of... N-hydroxysuccinimide and 0.315 mol triethylamine were mixed and added in 5 equal batches (5 min apart) to a DMF solution of 4'-carboxybenzo-15-crown 5-ether. The mixture was stirred and activated in an ice bath for 45 min. 0.1 mol intermediate A was added to 500 ml of anhydrous DMF and stirred until well mixed. The activated 4'-carboxybenzo-15-crown 5-ether DMF solution was slowly added dropwise over 1 h. The mixture was reacted at 25 °C for 8 h, then distilled under reduced pressure at 70 °C for 3 h. 2000 ml of anhydrous cold diethyl ether was added to precipitate the precipitate. The precipitate was filtered, washed with anhydrous diethyl ether (3 × 100 ml), and dried under vacuum at 60 °C for 8 h to obtain the dispersant.

[0053] Example 6: Preparation of dispersant:

[0054] N1: Under nitrogen protection, 0.1 mol of tricarboxylic acid was added to 100 ml of anhydrous toluene and stirred until well mixed. Then, 400 ml of anhydrous toluene solution containing 0.32 mol of 3-glycidyl etheroxypropyltriethoxysilane was slowly added dropwise over 1 hour. 0.305 mol of triethylamine was added, and the mixture was heated to 65 °C and reacted for 4 hours. The mixture was then cooled to room temperature and distilled under reduced pressure at 70 °C for 2 hours. 600 ml of anhydrous n-hexane was added and stirred to precipitate the precipitate. The precipitate was filtered, washed with cold anhydrous n-hexane (3 × 100 ml), and dried under vacuum at 60 °C for 8 hours to obtain intermediate A.

[0055] N2: Under nitrogen protection, 600 ml of anhydrous DMF and 0.32 mol of 4'-carboxybenzo-15-crown 5-ether were stirred and mixed thoroughly. Then, 0.32 mol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.32 mol of... N-hydroxysuccinimide and 0.32 mol triethylamine were mixed and added in 5 equal batches (5 min apart) to a DMF solution of 4'-carboxybenzo-15-crown 5-ether. The mixture was stirred and activated in an ice bath for 45 min. 0.1 mol intermediate A was added to 500 ml of anhydrous DMF and stirred until well mixed. The activated 4'-carboxybenzo-15-crown 5-ether DMF solution was slowly added dropwise over 1 h. The mixture was reacted at 30 °C for 7 h and then distilled under reduced pressure at 70 °C for 3 h. 2000 ml of anhydrous cold diethyl ether was added to precipitate the precipitate. The precipitate was filtered, washed with anhydrous diethyl ether (3 × 100 ml), and dried under vacuum at 60 °C for 8 h to obtain the dispersant.

[0056] Example 7: Preparation of Organosilicon Composite Solid Defoamer for Space Station Water Treatment:

[0057] (1) Weigh the following by weight: 25g of polydimethylsiloxane, 5g of water-soluble silicone oil, 10g of silica (hydrophobic silica), 3g of emulsifier (prepared in Example 1), 3g of dispersant (prepared in Example 4), and 25g of carrier (diatomaceous earth);

[0058] (2) Add polydimethylsiloxane, water-soluble silicone oil and silica to a mixer, heat to 120°C, stir at 500 rpm for 3 hours, cool to 40°C, add emulsifier and dispersant, stir for 2 hours, add carrier, stir and mix for 60 minutes to obtain a mixture, dry the mixture in a vacuum drying oven at 60°C for 3 hours, put it into a pulverizer, pulverize at 500 rpm for 20 minutes, pass through an 80-mesh sieve to obtain an organosilicon composite solid defoamer for space station water treatment.

[0059] Example 8: Preparation of organosilicon composite solid defoamer for space station water treatment:

[0060] (1) Weigh the following by weight: 30g of polydimethylsiloxane, 8g of water-soluble silicone oil, 12g of silica (hydrophobic silica), 4g of emulsifier (prepared in Example 2), 3.5g of dispersant (prepared in Example 5), and 30g of carrier (diatomaceous earth);

[0061] (2) Add polydimethylsiloxane, water-soluble silicone oil and fumed silica to a mixer, heat to 135°C, stir at 500 rpm for 2.5 h, cool to 50°C, add emulsifier and dispersant, stir for 1.5 h, add carrier, stir and mix for 45 min to obtain a mixture, dry the mixture in a vacuum drying oven at 60°C for 3 h, put it into a pulverizer, pulverize at 500 rpm for 20 min, pass through an 80 mesh sieve to obtain an organosilicon composite solid defoamer for space station water treatment.

[0062] Example 9: Preparation of Organosilicon Composite Solid Defoamer for Space Station Water Treatment:

[0063] (1) Weigh the following by weight: 35g of polydimethylsiloxane, 10g of water-soluble silicone oil, 15g of silica (hydrophobic silica), 5g of emulsifier (prepared in Example 3), 4g of dispersant (prepared in Example 6), and 35g of carrier (diatomaceous earth);

[0064] (2) Add polydimethylsiloxane, water-soluble silicone oil and silica to a mixer, heat to 150°C, stir at 500 rpm for 2 hours, cool to 60°C, add emulsifier and dispersant, stir for 1 hour, add carrier, stir and mix for 30 minutes to obtain a mixture, dry the mixture in a vacuum drying oven at 60°C for 3 hours, put it into a pulverizer, pulverize at 500 rpm for 20 minutes, pass through an 80-mesh sieve to obtain an organosilicon composite solid defoamer for space station water treatment.

[0065] Comparative Example 1

[0066] The raw material composition and preparation method of the organosilicon composite solid defoamer for space station water treatment are basically the same as those in Example 8, except that the emulsifier is replaced with an equal weight of emulsifier prepared by the following method:

[0067] The preparation method of the emulsifier is basically the same as that in Example 2, except that 1H,1H-perfluorohexylamine in step S1 is replaced with an equimolar amount of 2,2,3,3,4,4,4-heptafluorobutylamine.

[0068] Comparative Example 2

[0069] The raw material composition and preparation method of the organosilicon composite solid defoamer for space station water treatment are basically the same as those in Example 8, except that the emulsifier is replaced with an equal weight of emulsifier prepared by the following method:

[0070] The preparation method of the emulsifier is basically the same as that in Example 2, except that the dodecylamine in step S2 is replaced with an equimolar amount of 1-aminopentane.

[0071] Comparative Example 3

[0072] The raw material composition and preparation method of the organosilicon composite solid defoamer for space station water treatment are basically the same as those in Example 8, except that the emulsifier is replaced with an equal weight of emulsifier prepared by the following method:

[0073] The preparation method of the emulsifier is basically the same as that in Example 2, except that the amino-polyethylene glycol-carboxyl group in step S3 is replaced with 22g of amino-polyethylene glycol-carboxyl group with a number average molecular weight of 1000.

[0074] Comparative Example 4

[0075] The raw material composition and preparation method of the organosilicon composite solid defoamer for space station water treatment are basically the same as those in Example 8, except that the dispersant is replaced with an equal weight of dispersant prepared by the following method:

[0076] N1: Under nitrogen protection, 0.1 mol of propylene dicarboxylic acid was added to 100 ml of anhydrous toluene and stirred until well mixed. Then, 400 ml of anhydrous toluene solution containing 0.215 mol of 3-glycidyl etheroxypropyltriethoxysilane was slowly added dropwise over 30 min. 0.205 mol of triethylamine was added, and the mixture was heated to 60 °C and reacted for 5 h. After cooling to room temperature, the mixture was distilled under reduced pressure at 70 °C for 2 h. 600 ml of anhydrous n-hexane was added and stirred to precipitate the precipitate. The precipitate was filtered, washed with cold anhydrous n-hexane (3 × 100 ml), and dried under vacuum at 60 °C for 8 h to obtain the intermediate.

[0077] Under nitrogen protection, 600 ml of anhydrous DMF and 0.22 mol of 4'-carboxybenzo-15-crown 5-ether were stirred and mixed. 0.22 mol of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, 0.22 mol of N-hydroxysuccinimide, and 0.22 mol of triethylamine were mixed and added in 5 equal batches (5 min apart) to the DMF solution of 4'-carboxybenzo-15-crown 5-ether. The mixture was stirred and activated in an ice bath for 45 min. 0.1 mol of the intermediate was added to 500 ml of anhydrous DMF and stirred and mixed. The activated 4'-carboxybenzo-15-crown 5-ether DMF solution was slowly added dropwise over 1 h. The reaction was carried out at 25 °C for 8 h, followed by vacuum distillation at 70 °C for 3 h. 2000 ml of anhydrous cold diethyl ether was added to precipitate the precipitate. The precipitate was filtered, washed with anhydrous diethyl ether (3 × 100 ml), and dried under vacuum at 60 °C for 8 h to obtain the dispersant.

[0078] Comparative Example 5

[0079] The raw material composition and preparation method of the organosilicon composite solid defoamer for space station water treatment are basically the same as those in Example 8, except that the dispersant is replaced with an equal weight of dispersant prepared by the following method:

[0080] The preparation method of the dispersant is basically the same as that in Example 5, except that the 4'-carboxybenzo-15-crown 5-ether in step N2 is replaced with an equimolar amount of 4'-carboxybenzo-12-crown-4.

[0081] The polydimethylsiloxane used in the embodiments and comparative examples of this application has a number-average molecular weight of 115,000 Da; the water-soluble silicone oil is Cosmethicone. ® SF-939 is produced by Guangdong Biaomei Silicon Fluorine New Materials Co., Ltd.; the hydrophobic silica is model BT-386, produced by Shouguang Dinghao Chemical Materials Co., Ltd.; the diatomaceous earth is model TS509, with an average particle size of 30.5μm, produced by Qingdao Shengtai Silicon Industry Co., Ltd.

[0082] The defoaming, foam suppression and water dispersibility of the organosilicon composite solid defoamers for space station water treatment prepared in Examples 7-9 and Comparative Examples 1-5 were tested, and the test results are shown in Table 1.

[0083] Defoaming performance test: First, prepare 100 ml of a 1% sodium dodecylbenzenesulfonate aqueous solution, then pour it into a 500 ml graduated cylinder and bubble it with nitrogen gas until the 500 mark is reached. At this point, add 20 mg of solid defoamer and record the time required for the bubbles to completely disappear. Each sample is tested three times, and the average value is taken as the final defoaming time.

[0084] Defoaming performance test: First, prepare 100 ml of a 1% sodium dodecylbenzenesulfonate aqueous solution, then pour it into a 500 ml graduated cylinder and add 20 mg of defoamer. Next, purge with nitrogen gas at a flow rate of 2 L / min and record the time it takes for the bubbles to reach the 500 mark. Each sample was tested three times, and the average value was taken as the final defoaming time.

[0085] Water dispersibility test: Weigh 50g of water into a 500ml sealed bottle, add 5g of solid defoamer, seal the bottle, and place it in an ultrasonic oscillator (frequency 20kHz) for ultrasonic dispersion. Record the time it takes for the defoamer to be completely dispersed in the water (without turbidity). Each sample is tested 3 times, and the average value is taken.

[0086] Table 1

[0087]

[0088] As can be seen from Table 1, the organosilicon composite solid defoamers for space station water treatment prepared in Examples 7-9 of this application have excellent defoaming and foam-suppressing properties and good water dispersibility.

[0089] The organosilicon composite solid defoamers prepared in Examples 7-9 exhibit excellent defoaming and foam-suppressing properties because the emulsifiers prepared in these examples simultaneously contain hydrophilic long chains, long alkyl chains, and hydrophobic fluorocarbon chains of polyethylene glycol. The synergistic effect of the hydrophilic and hydrophobic structures enhances the defoaming and foam-suppressing capabilities of the solid defoamer. In contrast, the emulsifier prepared in Comparative Example 1 using 2,2,3,3,4,4,4-heptafluorobutylamine has fewer fluorocarbon chains, resulting in a higher surface tension and thus a weakened defoaming and foam-suppressing ability. The emulsifier prepared in Comparative Example 2 has shorter hydrophobic alkyl chains than the examples, which cannot effectively embed into the polydimethylsiloxane molecular chain, weakening the hydrophobic anchoring effect. The emulsifier prepared in Comparative Example 3 has shorter hydrophilic polyethylene glycol chains than the examples, resulting in reduced flexibility and a relatively higher surface tension, leading to a decrease in defoaming and foam-suppressing capabilities.

[0090] The organosilicon composite solid defoamers prepared in Examples 7-9 exhibit excellent water dispersibility, primarily due to the multi-branched structure of the dispersants. This structure forms a three-dimensional barrier on the surface of the defoamer particles, inhibiting random collisions and aggregation. Furthermore, the crown ether macrocyclic structure in the dispersant captures electrolyte ions in water, forming an ion-hydrated layer. This prevents flocculation caused by charge shielding of the dispersant under high-salt conditions, achieving stable dispersion in the aqueous phase. In contrast, the dispersant prepared in Comparative Example 4 has fewer branched chains than the examples, resulting in a weaker three-dimensional barrier effect on the defoamer particle surface. Additionally, the reduced number of siloxane units weakens the adsorption effect with the hydrophobic core of polydimethylsiloxane, leading to a decrease in the water dispersibility of the solid defoamer. In Comparative Example 5, 4'-carboxybenzo-15-crown 5-ether was replaced with 4'-carboxybenzo-12-crown-4. The crown ether cyclic structure is smaller than in the examples, resulting in a relatively weaker ability to capture electrolyte ions in water, thus leading to poorer water dispersibility of the solid defoamer compared to the examples.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A silicone composite solid antifoam agent for water treatment of a space station, characterized by comprising: The raw materials include the following weight parts: 25-35 parts of polydimethylsiloxane, 5-10 parts of water-soluble silicone oil, 10-15 parts of white carbon black, 3-5 parts of emulsifier, 3-4 parts of dispersant, and 25-35 parts of carrier; The emulsifier is prepared by the following method: S1: 1H, 1H-perfluorohexylamine reacts with epichlorohydrin to form intermediate 1, S2: intermediate 1 reacts with dodecylamine to form intermediate 2, S3: intermediate 2 reacts with amino-polyethylene glycol-carboxyl to form the emulsifier; The dispersant is prepared by the following method: N1: tricarballylic acid reacts with 3-glycidyl ether oxypropyl triethoxysilane to obtain intermediate A, N2: intermediate A reacts with 4'-carboxybenzo-15-crown-5-ether to obtain the dispersant.

2. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, In step S1, the molar ratio of 1H, 1H-perfluorohexylamine to epichlorohydrin is 1:(1.1-1.2).

3. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, In step S2, the molar ratio of intermediate 1 to dodecylamine is 1:(1.1-1.3).

4. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, In step S3, the mass ratio of intermediate 2 to amino-polyethylene glycol-carboxyl is 1:(4.1-4.8).

5. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, In step N1, the molar ratio of tricarballylic acid to 3-glycidyl ether oxypropyl triethoxysilane is 1:(3.1-3.2).

6. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, In step N2, the molar ratio of intermediate A to 4'-carboxybenzo-15-crown-5-ether is 1:(3.1-3.2).

7. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, The reaction temperature of step N1 is 55-65°C, and the reaction time is 4-6h.

8. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, The reaction temperature of step N2 is 25-30°C, and the reaction time is 7-9h.

9. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, The white carbon black is hydrophobic white carbon black.

10. The silicone composite solid defoamer for water treatment in space station according to claim 1, characterized in that, The carrier is diatomite.

11. A method for producing the silicone composite solid defoamer for water treatment of a space station according to any one of claims 1 to 10, characterized by, The method includes the following steps: (1) weighing by weight parts: 25-35 parts of polydimethylsiloxane, 5-10 parts of water-soluble silicone oil, 10-15 parts of white carbon black, 3-5 parts of emulsifier, 3-4 parts of dispersant, and 25-35 parts of carrier; (2) polydimethylsiloxane, water-soluble silicone oil and white carbon black are added to a mixer, heated and stirred to mix, cooled, then emulsifier, dispersant are added, stirred and mixed, carrier is added and stirred to mix to obtain a mixture, the mixture is dried, crushed, sieved to obtain an organic silicone composite solid defoaming agent for space station water treatment.

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