A renewable defoamer and its preparation method and application

Abstract

The application discloses a renewable defoaming agent and a preparation method and application thereof, and belongs to the technical field of defoaming agents. The specific steps are as follows: first, uniformly mixing chitosan, hydrogen-containing silicone oil, a solvent and a catalyst, heating and reacting, then adding vinyl silicone oil and fumed silica, and the renewable defoaming agent is obtained. The renewable defoaming agent prepared by the application has multiple functions in water treatment, can adsorb and flocculate, can control foam, has a small loss rate, a good biodegradation rate, and is environment-friendly, so that the pollution to the environment can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of defoamer technology, specifically relating to a renewable defoamer, its preparation method, and its application. Background Technology

[0002] Harmful foams are generated in industrial production processes such as latex removal, textile sizing, food fermentation, biopharmaceuticals, pesticides, coatings, petrochemicals, papermaking, and industrial cleaning. These foams can significantly reduce productivity, waste raw materials and products, and affect product quality. Therefore, defoamers are added during the production process.

[0003] Defoamers are mostly liquid compound products, mainly divided into four categories: mineral oil-based, silicone-based, polyether-based, and higher alcohol-based. Mineral oil-based defoamers typically consist of a carrier and surfactant. The carrier is a low surface tension substance whose function is to support and dilute the product; common carriers are water and fatty alcohols. Silicone-based defoamers generally include polydimethylsiloxane, etc. Silicone-based defoamers have poor solubility and exhibit rapid defoaming and good foam suppression at room temperature, but at high temperatures, they tend to separate into layers, resulting in slower defoaming and poorer foam suppression. Polyether-based defoamers include polyoxypropylene ethylene glycol ether, etc. Polyether-based defoamers are characterized by long foam suppression time, good effect, rapid defoaming speed, and good thermal stability. Higher alcohols are strongly hydrophobic and weakly hydrophilic linear molecules, making them effective defoamers in aqueous systems.

[0004] The trend towards water-based industrial production is inevitable. Whether it's water-based coatings or water-based pesticides, water-based production inevitably generates foam that can harm industrial processes, necessitating physical defoaming or chemical defoaming. Furthermore, increasingly stringent national environmental protection requirements have placed environmental sustainability demands on additives.

[0005] Chitosan, chemically known as polyglucosamine (1-4)-2-amino-BD glucose, is derived from chitin, a widely distributed natural compound, through deacetylation. Since its initial discovery by the Frenchman Rouget in 1859, this natural polymer has garnered significant attention across various industries due to its excellent biocompatibility, blood compatibility, safety, and microbial degradability. Its applications in medicine, food, chemical industry, cosmetics, water treatment, metal extraction and recovery, biochemistry, and biomedical engineering have achieved substantial progress. For patients, research reports have documented the lipid-lowering and blood glucose-lowering effects of chitosan.

[0006] Chitosan, a product of chitin deacetylation, exhibits significantly improved solubility due to the presence of abundant free ammonia in its molecular structure. It possesses unique physicochemical properties and physiological functions, showing broad application prospects in agriculture, medicine, food, cosmetics, and environmental protection. The main raw materials for chitosan preparation come from discarded shrimp and crab shells from aquatic product processing plants, and its main components are calcium carbonate, protein, and chitin (approximately 20%). The process of preparing chitosan from shrimp and crab shells is essentially a process of decalcification, protein removal, decolorization, and deacetic acid removal. Summary of the Invention

[0007] To address the aforementioned problems in the existing technology, the first technical problem to be solved by this invention is to provide a simple method for preparing a renewable defoamer, thereby obtaining a renewable defoamer. The second technical problem to be solved by this invention is to provide a renewable, biodegradable, energy-saving, and environmentally friendly defoamer. The third technical problem to be solved by this invention is to provide an application of the renewable defoamer in water treatment.

[0008] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a renewable defoamer involves first mixing chitosan, hydrogen-containing silicone oil, solvent, and catalyst evenly, heating and reacting the mixture, and then adding vinyl silicone oil and fumed silica to obtain the renewable defoamer.

[0010] The heating temperature is 100–140°C.

[0011] The hydrogen-containing silicone oil is one or more of heptamethyltrisiloxane, side-chain hydrogen-containing silicone oil, and end-chain hydrogen-containing silicone oil.

[0012] The hydrogen-containing silicone oil is preferably an end-chain hydrogen-containing silicone oil with a viscosity of 10–400 Pa·s and a hydrogen content of 0.01–0.5%; more preferably, it has a viscosity of 50–100 Pa·s and a hydrogen content of 0.05–0.3%.

[0013] The solvent is one or more of ethylene glycol monobutyl ether, toluene, and xylene.

[0014] The vinyl silicone oil is one or more of terminal vinyl silicone oil, side-chain vinyl silicone oil, and terminal-side vinyl silicone oil.

[0015] The vinyl silicone oil is preferably a vinyl-terminated silicone oil with a viscosity of 10–10000 Pa·s; more preferably, it has a viscosity of 200–1000 Pa·s.

[0016] The fumed silica produced by the fumed silica process is preferably hydrophobic silica with a specific surface area of ​​130–380 m². 2 / g; preferably, the specific surface area is 200-300m².2 / g.

[0017] The method described yields a renewable defoamer.

[0018] The application of the renewable defoamer in adsorption, flocculation and defoaming.

[0019] Beneficial effects: Compared with the prior art, the advantages of this invention are:

[0020] (1) The raw materials used in this invention are derived from the shrimp and crab shells discarded by aquatic product processing plants. This invention is energy-saving and environmentally friendly, and it utilizes waste, reducing the waste of resources. In addition, this invention has a good biodegradability rate, which greatly reduces the pollution to the environment.

[0021] (2) This invention uses chitosan as raw material, modifies it with vinyl silicone oil to obtain organosilicon, and adsorbs a small amount of fumed silica, which can improve the product effect.

[0022] (3) The defoamer prepared by the present invention has multiple functions in water treatment, including adsorption and flocculation, and foam control.

[0023] (4) Traditional defoamers are constantly consumed as the treated water is lost, while the defoamer prepared by this invention can greatly reduce the loss rate and reduce production costs. Detailed Implementation

[0024] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0025] Example 1

[0026] Preparation of renewable defoamer: 100 kg of chitosan and 30 kg of xylene solvent were mixed and heated to 85°C. After the chitosan dissolved, 15.3 kg of side-chain hydrogen-containing silicone oil with a viscosity of 50 Pa·s (0.5% hydrogen content) was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120°C for 4 hours. Then, 9.2 kg of terminal vinyl silicone oil with a viscosity of 350 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120°C for 2 hours. Finally, 1.3 kg of [amount missing] [unit missing] [surface area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [surface area ... 2 / g of hydrophobic silica was used. After the hydrophobic silica was fully adsorbed, the solvent xylene was finally removed to obtain a regenerable defoamer.

[0027] Example 2

[0028] Preparation of renewable defoamer: 100 kg of chitosan and 30 kg of xylene solvent were mixed and heated to 92°C. After the chitosan dissolved, 22.4 kg of side-chain hydrogen-containing silicone oil with a viscosity of 100 Pa·s (hydrogen content 0.18%) was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120°C for 4 hours. Then, 12.8 kg of terminal vinyl silicone oil with a viscosity of 500 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120°C for 2 hours. Finally, 1.5 kg of [amount missing] [unit missing] [surface area missing] [area ... 2 / g of hydrophobic silica was used. After the hydrophobic silica was fully adsorbed, the solvent xylene was finally removed to obtain a regenerable defoamer.

[0029] Example 3

[0030] Preparation of renewable defoamer: 100 kg of chitosan and 30 kg of xylene solvent were mixed and heated to 85°C. After the chitosan dissolved, 22.4 kg of side-chain hydrogen-containing silicone oil with a viscosity of 100 Pa·s (hydrogen content 0.18%) was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120°C for 4 hours. Then, 16.3 kg of terminal vinyl silicone oil with a viscosity of 1000 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120°C for 2 hours. Finally, 1.6 kg of [amount missing] specific surface area [area missing] was added. 2 / g of hydrophobic silica was used. After the hydrophobic silica was fully adsorbed, the solvent xylene was finally removed to obtain a regenerable defoamer.

[0031] Example 4

[0032] Preparation of renewable defoamer: 100 kg of chitosan and 30 kg of xylene solvent were mixed and heated to 92°C. After the chitosan dissolved, 23.8 kg of side-chain hydrogen-containing silicone oil with a viscosity of 100 Pa·s (hydrogen content of 0.18%) was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120°C for 4 h. Then, 14.3 kg of terminal vinyl silicone oil with a viscosity of 500 Pa·s and Karstedt platinum catalyst were added, and the mixture was reacted at 120°C for 2 h. Finally, xylene solvent was removed to obtain the renewable defoamer.

[0033] Example 5

[0034] Preparation of renewable defoamer: 100 kg of chitosan and 30 kg of xylene solvent were mixed and heated to 95°C. After the chitosan dissolved, 28.3 kg of hydrogen-terminated silicone oil with a viscosity of 350 Pa·s (0.043% hydrogen content) was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120°C for 4 hours. Then, 8.5 kg of vinyl-terminated silicone oil with a viscosity of 500 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120°C for 2 hours. Finally, 1.5 kg of defoamer with a specific surface area of ​​300 m² was added. 2 / g of hydrophobic silica was used. After the hydrophobic silica was fully adsorbed, the solvent xylene was finally removed to obtain a regenerable defoamer.

[0035] Comparative Example 1

[0036] Taking the defoamer (KZX-7410) used in the biological treatment tank of a water treatment plant as a comparison, this defoamer is an organosilicon emulsion defoamer, which has two addition methods: one is to add the defoamer once every four hours, and the other is to dilute the organosilicon emulsion defoamer and add it continuously.

[0037] The defoamer prepared by this invention is added directly to the aeration tank in one go. After about ten days when foam appears, the defoamer is added again in one go. The results are shown in Table 1 below.

[0038] Table 1 Comparison of the amount of defoaming agent used in a certain silicone emulsion and the defoamer prepared in this invention.

[0039]

[0040]

[0041] Table 1 compares the amount of defoaming agent used in a certain silicone emulsion and the defoamer prepared according to this invention. As shown in Table 1, in water treatment processes, traditional defoamers need to be continuously added as water is lost. However, the defoamer of this invention can be added once and then added again after a longer period of time. Compared with traditional defoamers, the amount of defoamer used in this embodiment is lower, more environmentally friendly and safer, and reduces the number of process steps.

[0042] Comparative Example 2

[0043] Take 200mL of wastewater that a company needs to treat and add it to a laboratory circulating bubbler. Set the temperature to 80℃ and turn on the circulating bubbler. When the foam reaches 400mL, add defoamer and record the time required for the foam to disappear as the defoaming time. Then, when the foam reaches 400mL again, record the time as the foam suppression time.

[0044] Table 2 Comparison of the amount of defoaming agent used in silicone emulsion and the defoamer prepared in this invention.

[0045]

[0046] Table 2 is a comparison table of the amount of defoaming agent used in the defoaming of silicone emulsion and the defoamer prepared in this invention. As shown in Table 2, the diffusion speed of this embodiment is not as fast as that of traditional defoamers, but the foam suppression time is greatly increased.

[0047] Comparative Example 3

[0048] Comparison of defoamers used in pesticide water suspensions:

[0049] The main production process of water-based suspension concentrates involves high-speed dispersion and milling of pesticides, adjuvants, and water. This process generates a large amount of foam, and a defoamer of 0.2% to 0.5% is always added during this process. With traditional defoamers, their effectiveness diminishes to negligible levels after milling, rendering them ineffective. However, the defoamer prepared by this invention can be filtered out during the filling process after milling and reused.

[0050] Taking 35% SC of chlorothalonil and carbendazim as examples:

[0051] Table 3 Comparison of defoaming effects between silicone emulsion and the defoamer prepared in this invention.

[0052]

[0053] Table 3 is a comparison table of defoaming effects of silicone emulsion and the defoamer prepared in this invention. As can be seen from Table 3, with the same amount of addition, the higher the density after grinding, the better the defoaming effect. The defoamer in this embodiment is better than the traditional defoamer, and the defoamer in this embodiment can be recycled.

Claims

1. A method for preparing a renewable defoamer, characterized in that, 100 kg of chitosan was mixed with 30 kg of xylene solvent and heated to 85°C. After the chitosan dissolved, 15.3 kg of hydrogen-containing side-chain silicone oil with a viscosity of 50 Pa·s and a hydrogen content of 0.5% was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120°C for 4 hours. Then, 9.2 kg of vinyl-terminated silicone oil with a viscosity of 350 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120°C for 2 hours. Finally, 1.3 kg of [amount missing] m² of [material missing] specific surface area [area missing] was added. 2 / g of hydrophobic silica was used. After the hydrophobic silica was fully adsorbed, the solvent xylene was finally removed to obtain a regenerable defoamer.

2. A method for preparing a renewable defoamer, characterized in that: 100 kg of chitosan was mixed with 30 kg of xylene solvent and heated to 92 °C. After the chitosan dissolved, 22.4 kg of side-chain hydrogen-containing silicone oil with a viscosity of 100 Pa·s and a hydrogen content of 0.18% was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120 °C for 4 h. Then, 12.8 kg of terminal vinyl silicone oil with a viscosity of 500 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120 °C for 2 h. Finally, 1.5 kg of [amount missing] [unit missing] [surface area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [area missing] [surface area ... 2 / g of hydrophobic silica was used. After the hydrophobic silica was fully adsorbed, the solvent xylene was finally removed to obtain a regenerable defoamer.

3. A method for preparing a renewable defoamer, characterized in that: 100 kg of chitosan was mixed with 30 kg of xylene solvent and heated to 85 °C. After the chitosan dissolved, 22.4 kg of side-chain hydrogen-containing silicone oil with a viscosity of 100 Pa·s and a hydrogen content of 0.18% was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120 °C for 4 h. Then, 16.3 kg of terminal vinyl silicone oil with a viscosity of 1000 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120 °C for 2 h. Finally, 1.6 kg of [amount missing] m² of [material missing] specific surface area [missing information] was added. 2 / g of hydrophobic silica was used. After the hydrophobic silica was fully adsorbed, the solvent xylene was finally removed to obtain a regenerable defoamer.

4. A method for preparing a renewable defoamer, characterized in that: 100 kg of chitosan was mixed with 30 kg of xylene solvent and heated to 92 °C. After the chitosan dissolved, 23.8 kg of side-chain hydrogen-containing silicone oil with a viscosity of 100 Pa·s and a hydrogen content of 0.18% was added, followed by the addition of tetramethylammonium hydroxide catalyst. The mixture was reacted at 120 °C for 4 h. Then, 14.3 kg of terminal vinyl silicone oil with a viscosity of 500 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120 °C for 2 h. Finally, the xylene solvent was removed to obtain a regenerable defoamer.

5. A method for preparing a renewable defoamer, characterized in that: 100 kg of chitosan was mixed with 30 kg of xylene solvent and heated to 95°C. After the chitosan dissolved, 28.3 kg of hydrogen-terminated silicone oil with a viscosity of 350 Pa·s and a hydrogen content of 0.043% was added, followed by tetramethylammonium hydroxide catalyst. The mixture was reacted at 120°C for 4 hours. Then, 8.5 kg of vinyl-terminated silicone oil with a viscosity of 500 Pa·s and a Karstedt platinum catalyst were added, and the mixture was reacted at 120°C for 2 hours. Finally, 1.5 kg of silicone oil with a specific surface area of ​​300 m² was added. 2 / g of hydrophobic silica was used. After the hydrophobic silica was fully adsorbed, the solvent xylene was finally removed to obtain a regenerable defoamer.

6. The renewable defoamer prepared by the method according to any one of claims 1 to 5.

7. The application of the renewable defoamer according to claim 6 in adsorption, flocculation and defoaming.

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