Method for recovering waste water from a silane coupling agent production plant

Abstract

This invention discloses a wastewater recovery method for a silane coupling agent production workshop, belonging to the field of wastewater treatment technology. The wastewater recovery method for the silane coupling agent production workshop includes the following steps: Step (1): First, wastewater is discharged into a first equalization tank through a screen, and then pumped to a flotation tank for flotation to obtain pretreated wastewater; Step (2): The pretreated wastewater flows into a four-effect evaporation system by gravity to obtain concentrated wastewater, which is then pumped to a second equalization tank for cooling, flows through a coagulation sedimentation tank, and is pumped to a third equalization tank to obtain equalization tank effluent; Step (3): The equalization tank effluent enters a biological treatment unit to obtain biologically treated wastewater, which is then pumped to a fourth equalization tank containing a composite adsorbent to obtain recyclable water. This method can effectively remove pollutants from wastewater, and the recyclable water meets emission standards.

Description

Technical Field

[0001] This invention belongs to the field of wastewater recycling technology, specifically relating to a wastewater recycling method in a silane coupling agent production workshop. Background Technology

[0002] With the rapid advancement of technology and the acceleration of industrialization, silane coupling agents, as an important chemical raw material, have been widely used in surface treatment, composite material manufacturing, coatings, and adhesives. However, this widespread application is accompanied by the generation of large amounts of wastewater containing silane coupling agents and their byproducts. If this wastewater is discharged directly without effective treatment, it will cause serious environmental pollution.

[0003] Wastewater from silane coupling agent production facilities mainly contains unreacted silane compounds, alcohols, acids, and other organic substances, as well as some heavy metal ions. Silane compounds are not only highly biotoxic and difficult to degrade, but may also have long-term impacts on aquatic ecosystems. Alcohols and acids can alter the pH of water bodies, affecting the living environment of aquatic organisms. The presence of heavy metal ions poses a long-term, cumulative pollution threat to the environment. Therefore, wastewater recycling and treatment in silane coupling agent production workshops has become a crucial issue that must be addressed on the path to green industrial development.

[0004] Patent CN 104692558 B discloses a method for recycling paint wastewater and its application. The method includes the following steps: removing slag and performing primary screening on the paint wastewater; adding a dispersant to the primary screened paint wastewater to ensure uniform dispersion; adding a stabilizer to the uniformly dispersed paint wastewater to maintain a stable dispersion state; heating the stabilized paint wastewater; adding a defoamer to the heated paint wastewater; and screening the defoamed paint wastewater again. This invention offers high operability, avoiding the high operating costs and paint quality issues associated with waste paint membrane concentration and reuse equipment, as well as the problems of solid content and secondary wastewater pollution from waste paint pressure filtration extraction. However, this method is not suitable for treating wastewater generated in silane coupling agent production workshops. Summary of the Invention

[0005] The purpose of this invention is to provide a wastewater recovery method for silane coupling agent production workshops, which solves the technical problems of low pollutant removal efficiency and substandard wastewater discharge in the existing technology.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for wastewater recovery in a silane coupling agent production workshop, comprising the following steps:

[0008] Step (1): First, the wastewater from the silane coupling agent production workshop is discharged into the first equalization tank through a screen, and then the wastewater in the first equalization tank is pumped to the flotation tank for flotation to obtain pretreated wastewater.

[0009] During the above process, tiny, dense bubbles are continuously generated in the flotation tank. The floating oil in the wastewater combines with the bubbles to form a layer of scum on the surface. The scum is removed by the scum scraper that is equipped with the flotation tank, thus achieving the separation of floating oil and insoluble pollutants in the wastewater.

[0010] Step (2): The pretreated wastewater flows into the four-effect evaporation system by gravity for evaporation and desalination to obtain concentrated wastewater. The concentrated wastewater is pumped to the second equalization tank for cooling, and after flowing through the coagulation sedimentation tank, it is pumped to the third equalization tank to obtain the equalization tank effluent.

[0011] Step (3): The effluent from the equalization tank enters the biological treatment unit to obtain biologically treated wastewater. Then, the biologically treated wastewater is pumped to the fourth equalization tank containing composite adsorbent to obtain recyclable water.

[0012] Preferably, in step (1), sulfuric acid or sodium hydroxide is added to the first conditioning tank to adjust the pH to 7-7.2.

[0013] Preferably, in step (2), the four-effect evaporation system operates in a vacuum environment. The pretreated wastewater is first fed into the first evaporator, and fresh steam is simultaneously fed in to heat the pretreated wastewater. The generated secondary steam is introduced into the second evaporator, so that the evaporation temperature of the wastewater in the second evaporator is lower than that in the first evaporator. This process is repeated until the fourth evaporator is reached, resulting in concentrated wastewater.

[0014] Preferably, in step (3), the biological treatment unit contains a modified biofilm, and the method for preparing the modified biofilm includes the following steps:

[0015] Q1: Dissolve 4-azidoaniline hydrochloride in diethyl ether, then add sodium bicarbonate solution, stir under light at room temperature, then separate the diethyl ether layer, add methacrylic acid, N,N'-dicyclohexylcarboimide and 4-dimethylaminopyridine to the diethyl ether layer, stir under light, filter, extract, dry, and rotary evaporate to obtain intermediate product 1;

[0016] Q2: Add intermediate product 1, azobisisobutyronitrile and N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine to an ethanol solution, heat and stir under argon protection, and then add ethanol, centrifuge, wash, and vacuum dry to obtain intermediate product 2.

[0017] Q3: The polyethylene was washed with acetone, dried, and then treated with plasma. The treated polyethylene was then immersed in a sodium chloride solution containing intermediate product 2. After immersion, it was removed, dried, irradiated, and washed to obtain a modified biofilm.

[0018] In the above process, 4-azidoaniline hydrochloride and methacrylic acid first undergo esterification reaction under the conditions of N,N'-dicyclohexylcarboimide as condensing agent and 4-dimethylaminopyridine as catalyst to obtain intermediate product 1. Then, intermediate product 1 and N-(3-sulfopropyl)-N-methpropyleneoxyethyl-N,N-dimethylammonium betaine undergo polymerization reaction under the conditions of azobisisobutyronitrile as free radical initiator to obtain intermediate product 2. Then, polyethylene and intermediate product 2 are composited by soaking and irradiation curing to obtain modified biofilm.

[0019] Preferably, in Q1, the ratio of 4-azidoaniline hydrochloride, sodium bicarbonate solution, methacrylic acid, N,N'-dicyclohexylcarboimide, and 4-dimethylaminopyridine is (0.15-0.45)g:(10-30)mL:(0.077-0.231)mL:(0.21-0.63)g:(0.01-0.04)g, the sodium bicarbonate solution has a weight fraction of 5wt%, the stirring time is 10-15 min at room temperature under light, and the stirring time is 10-12 h under light. Extraction is first performed with 5wt% sodium bicarbonate solution, followed by extraction with deionized water.

[0020] Preferably, in Q2, the ratio of intermediate product 1, azobisisobutyronitrile, N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine, ethanol solution, and ethanol is (1-3)g:(0.004-0.012)g:(2-5)g:(2-6)mL:(5-30)mL, the volume fraction of the ethanol solution is 33vt%, the heating and stirring temperature is 55-60℃, and the time is 5-6h; in Q3, the plasma treatment process is as follows: plasma etching is performed at 80W for 40s, the concentration of sodium chloride solution is 1mol / L, the soaking time is 5-10min, the irradiation time is 40-60min, and the product is first washed with 0.1mol / L sodium chloride solution, followed by deionization washing.

[0021] Preferably, the preparation method of the composite adsorbent includes the following steps:

[0022] S1: Dissolve copper nitrate trihydrate in deionized water to obtain copper nitrate trihydrate solution. Then, sonicately dissolve trimellitic acid in anhydrous ethanol to obtain trimellitic acid solution. Add copper nitrate trihydrate solution and trimellitic acid solution to a container for mixing. After heating and reacting, a solid-liquid mixture is obtained. Centrifuge, ultrasonically clean the precipitate, and dry it to obtain intermediate product A.

[0023] S2: Polyethyleneimine and styrene-maleic anhydride copolymer were dissolved in dimethyl sulfoxide to obtain polyethyleneimine solution and styrene-maleic anhydride copolymer solution, respectively. Then, the styrene-maleic anhydride copolymer solution was added dropwise to the polyethyleneimine solution, reacted, dialyzed, freeze-dried under vacuum, and pulverized to obtain intermediate product B.

[0024] S3: Disperse intermediate product B in deionized water using ultrasound, then add intermediate product A, stir, and vacuum dry to obtain the composite adsorbent.

[0025] In the above process, intermediate product A is first prepared by a solvothermal method. Then, using polyethyleneimine and styrene-maleic anhydride copolymer as raw materials, intermediate product B is prepared by a one-step amidation reaction. Then, intermediate product B is used as a filler and doped into intermediate product A to prepare a composite adsorbent. The synthesis reaction formula of intermediate product B is as follows:

[0026]

[0027] Preferably, in step S1, the ratio of copper nitrate trihydrate, deionized water, trimesic acid, and anhydrous ethanol is (1.45-2.18)g:(20-30)mL:(0.84-1.25)g:(20-30)mL, the reaction temperature is 120-130℃, the reaction time is 20-24h, the centrifugation speed is 5000-6000rpm, the centrifugation time is 5-8min, the ultrasonic cleaning time is 3-6min, the drying temperature is 60-70℃, and the drying time is 10-12h.

[0028] Preferably, in S2, the mass ratio of polyethyleneimine to styrene-maleic anhydride copolymer is (0.5-1):(0.8-1.6), the reaction time is 22-24 h, and the dialysis process is: dialysis in deionized water using a cellulose dialysis membrane for 24 h.

[0029] Preferably, in step S3, the ratio of intermediate product B, deionized water and intermediate product A is (4-6)g:(10-20)mL:(6-9)g, the ultrasonic dispersion time is 10-15min, the stirring time is 6-8h, the vacuum drying temperature is 60-80℃, and the vacuum drying time is 10-12h.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] 1. This invention first uses 4-azidoaniline hydrochloride, methacrylic acid, N,N'-dicyclohexylcarboimide, N-(3-sulfopropyl)-N-methpropyleneoxyethyl-N,N-dimethylammonium betaine and polyethylene as raw materials to prepare a modified biofilm. Subsequently, a composite adsorbent is prepared using copper nitrate trihydrate, trimesic acid, polyethyleneimine and styrene-maleic anhydride copolymer as raw materials. The modified biofilm and composite adsorbent are then applied to wastewater treatment in a silane coupling agent production workshop, which can effectively reduce pollutant concentrations and enable the wastewater to meet discharge standards.

[0032] 2. This invention uses 4-azidoaniline hydrochloride, methacrylic acid, N,N'-dicyclohexylcarboimide, N-(3-sulfopropyl)-N-methpropyleneoxyethyl-N,N-dimethylammonium betaine, and polyethylene as raw materials to prepare a modified biofilm. When applied to wastewater treatment, this modified biofilm can effectively reduce pollutant concentrations. The structure on the surface of the modified biofilm can effectively adsorb or degrade organic pollutants in wastewater, reducing their concentration. The microorganisms on the modified biofilm degrade pollutants in the wastewater through metabolic activities, converting them into harmless or low-toxic substances. Furthermore, the obtained modified biofilm not only possesses excellent mechanical strength but also exhibits chemical corrosion resistance, allowing it to remain stable for extended periods during wastewater treatment and improving its treatment efficiency.

[0033] 3. This invention uses copper nitrate trihydrate, trimesic acid, polyethyleneimine, and styrene-maleic anhydride copolymer as raw materials to prepare a composite adsorbent. When applied to the wastewater treatment process in a silane coupling agent production workshop, it can effectively reduce the concentration of pollutants. The components in the composite adsorbent can adsorb organic pollutants in the wastewater through physical and chemical reactions, reducing their concentration in the water. The high porosity of intermediate product A can not only adsorb pollutants in the wastewater, but also serve as a carrier for intermediate product B, which has excellent hydrophilic and lipophilic properties. Through the synergistic effect of the two, the concentration of pollutants in the wastewater is greatly reduced, enabling it to meet the discharge standards. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic flowchart of the wastewater recovery method in the silane coupling agent production workshop of the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment discloses a method for preparing a modified biofilm, including the following steps:

[0039] Q1: Dissolve 0.3 g of 4-azidoaniline hydrochloride in 10 mL of diethyl ether, then add 20 mL of 5 wt% sodium bicarbonate solution, stir in the dark at room temperature for 15 min, then separate the diethyl ether layer, add 0.154 mL of methacrylic acid, 0.42 g of N,N'-dicyclohexylcarboimide and 0.025 g of 4-dimethylaminopyridine to the diethyl ether layer, stir in the dark for 12 h, filter, first extract with 5 wt% sodium bicarbonate solution, then extract with deionized water, dry, and rotary evaporate to obtain intermediate product 1;

[0040] Q2: 2g of intermediate product 1, 0.008g of azobisisobutyronitrile and 3.5g of N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine were added to 4mL of 33vt% ethanol solution. The mixture was heated and stirred at 60°C for 6h under argon protection and light protection. After stirring, 17mL of ethanol was added, the mixture was centrifuged, washed, and dried under vacuum to obtain intermediate product 2.

[0041] Q3: Wash 2g of polyethylene with 10mL of acetone, dry it, and then treat it with plasma. The plasma treatment process is as follows: treat with plasma etching at 80W for 40s, then immerse the treated polyethylene in a 1mol / L sodium chloride solution containing 0.3g of intermediate product 2 for 10min, take it out, dry it, irradiate it for 60min, wash it with 0.1mol / L sodium chloride solution, and then wash it with deionized water to obtain the modified biofilm.

[0042] This embodiment discloses a method for preparing a composite adsorbent, including the following steps:

[0043] S1: Dissolve 1.82g of copper nitrate trihydrate in 25mL of deionized water to obtain a copper nitrate trihydrate solution. Then, dissolve 0.105g of trimellitic acid in 25mL of anhydrous ethanol by sonication to obtain a trimellitic acid solution. Add the copper nitrate trihydrate solution and the trimellitic acid solution to a container and mix them. After reacting at 130℃ for 24h, a solid-liquid mixture is obtained. Centrifuge at 6000rpm for 8min, sonicate the precipitate for 6min, and dry at 70℃ for 12h to obtain intermediate product A.

[0044] S2: 0.75g of polyethyleneimine and 1.2g of styrene-maleic anhydride copolymer were dissolved in 20mL of dimethyl sulfoxide to obtain polyethyleneimine solution and styrene-maleic anhydride copolymer solution, respectively. Then, the styrene-maleic anhydride copolymer solution was added dropwise to the polyethyleneimine solution and reacted for 24h. The mixture was dialyzed in deionized water using a cellulose dialysis membrane for 24h, then freeze-dried under vacuum and pulverized to obtain intermediate product B.

[0045] S3: Disperse 5g of intermediate product B in 15mL of deionized water by ultrasonication for 10min, then add 7.5g of intermediate product A, stir for 8h, and vacuum dry at 80℃ for 12h to obtain the composite adsorbent.

[0046] See Figure 1 As shown in the figure, this embodiment discloses a wastewater recovery method in a silane coupling agent production workshop, including the following steps:

[0047] Step (1): First, the wastewater from the silane coupling agent production workshop is discharged into the first equalization tank through a screen. Sulfuric acid or sodium hydroxide is added to the first equalization tank to adjust the pH to 7. Then, the wastewater in the first equalization tank is pumped to the flotation tank for flotation to obtain pretreated wastewater.

[0048] Step (2): The pretreated wastewater flows into the four-effect evaporation system by gravity. The four-effect evaporation system operates in a vacuum environment. The pretreated wastewater is first sent into the first evaporator. Fresh steam is sent in at the same time to heat the pretreated wastewater. The generated secondary steam is introduced into the second evaporator so that the evaporation temperature of the wastewater in the second evaporator is lower than that in the first evaporator. This process is carried out in sequence to the fourth evaporator for evaporation and desalination to obtain concentrated wastewater. The concentrated wastewater is pumped to the second equalization tank for cooling. After flowing through the coagulation sedimentation tank, it is pumped to the third equalization tank to obtain the equalization tank effluent.

[0049] Step (3): The effluent from the equalization tank enters the biological treatment unit containing the modified biofilm to obtain biologically treated wastewater. Then, the biologically treated wastewater is pumped to the fourth equalization tank containing the composite adsorbent to obtain recyclable water.

[0050] Example 2

[0051] This embodiment discloses a method for preparing a modified biofilm, including the following steps:

[0052] Q1: Dissolve 0.15 g of 4-azidoaniline hydrochloride in 10 mL of diethyl ether, then add 10 mL of 5 wt% sodium bicarbonate solution, stir in the dark at room temperature for 15 min, then separate the diethyl ether layer, add 0.077 mL of methacrylic acid, 0.21 g of N,N'-dicyclohexylcarboimide and 0.01 g of 4-dimethylaminopyridine to the diethyl ether layer, stir in the dark for 12 h, filter, first extract with 5 wt% sodium bicarbonate solution, then extract with deionized water, dry, and rotary evaporate to obtain intermediate product 1;

[0053] Q2: 1g of intermediate product 1, 0.004g of azobisisobutyronitrile and 2g of N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine were added to 2mL of ethanol solution with a volume fraction of 33vt%. The mixture was heated and stirred at 60°C for 6h under argon protection and light protection. After stirring, 5mL of ethanol was added, the mixture was centrifuged, washed, and dried under vacuum to obtain intermediate product 2.

[0054] Q3: Wash 2g of polyethylene with 10mL of acetone, dry it, and then treat it with plasma. The plasma treatment process is as follows: treat with plasma etching at 80W for 40s, then immerse the treated polyethylene in a 1mol / L sodium chloride solution containing 0.3g of intermediate product 2 for 10min, take it out, dry it, irradiate it for 60min, wash it with 0.1mol / L sodium chloride solution, and then wash it with deionized water to obtain the modified biofilm.

[0055] This embodiment discloses a method for preparing a composite adsorbent, including the following steps:

[0056] S1: Dissolve 1.45g of copper nitrate trihydrate in 20mL of deionized water to obtain a copper nitrate trihydrate solution. Then, dissolve 0.084g of trimellitic acid in 30mL of anhydrous ethanol by sonication to obtain a trimellitic acid solution. Add the copper nitrate trihydrate solution and the trimellitic acid solution to a container and mix them. After reacting at 130℃ for 24h, a solid-liquid mixture is obtained. Centrifuge at 6000rpm for 8min, sonicate the precipitate for 6min, and dry at 70℃ for 12h to obtain intermediate product A.

[0057] S2: Dissolve 0.5g of polyethyleneimine and 0.8g of styrene-maleic anhydride copolymer in 20mL of dimethyl sulfoxide to obtain polyethyleneimine solution and styrene-maleic anhydride copolymer solution, respectively. Then, add the styrene-maleic anhydride copolymer solution dropwise to the polyethyleneimine solution and react for 24h. Dialyze the mixture in deionized water using a cellulose dialysis membrane for 24h, freeze-dry under vacuum, and pulverize to obtain intermediate product B.

[0058] S3: Disperse 4g of intermediate product B in 10mL of deionized water by ultrasonication for 10min, then add 6g of intermediate product A, stir for 8h, and vacuum dry at 80℃ for 12h to obtain the composite adsorbent.

[0059] See Figure 1 As shown in the figure, this embodiment discloses a wastewater recovery method in a silane coupling agent production workshop, including the following steps:

[0060] Step (1): First, the wastewater from the silane coupling agent production workshop is discharged into the first equalization tank through a screen. Sulfuric acid or sodium hydroxide is added to the first equalization tank to adjust the pH to 7. Then, the wastewater in the first equalization tank is pumped to the flotation tank for flotation to obtain pretreated wastewater.

[0061] Step (2): The pretreated wastewater flows into the four-effect evaporation system by gravity. The four-effect evaporation system operates in a vacuum environment. The pretreated wastewater is first sent into the first evaporator. Fresh steam is sent in at the same time to heat the pretreated wastewater. The generated secondary steam is introduced into the second evaporator so that the evaporation temperature of the wastewater in the second evaporator is lower than that in the first evaporator. This process is carried out in sequence to the fourth evaporator for evaporation and desalination to obtain concentrated wastewater. The concentrated wastewater is pumped to the second equalization tank for cooling. After flowing through the coagulation sedimentation tank, it is pumped to the third equalization tank to obtain the equalization tank effluent.

[0062] Step (3): The effluent from the equalization tank enters the biological treatment unit containing the modified biofilm to obtain biologically treated wastewater. Then, the biologically treated wastewater is pumped to the fourth equalization tank containing the composite adsorbent to obtain recyclable water.

[0063] Example 3

[0064] This embodiment discloses a method for preparing a modified biofilm, including the following steps:

[0065] Q1: Dissolve 0.45 g of 4-azidoaniline hydrochloride in 10 mL of diethyl ether, then add 30 mL of 5 wt% sodium bicarbonate solution, stir in the dark at room temperature for 15 min, then separate the diethyl ether layer, add 0.231 mL of methacrylic acid, 0.63 g of N,N'-dicyclohexylcarboimide and 0.04 g of 4-dimethylaminopyridine to the diethyl ether layer, stir in the dark for 12 h, filter, first extract with 5 wt% sodium bicarbonate solution, then extract with deionized water, dry, and rotary evaporate to obtain intermediate product 1;

[0066] Q2: 3g of intermediate product 1, 0.012g of azobisisobutyronitrile and 5g of N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine were added to 6mL of ethanol solution with a volume fraction of 33vt%. The mixture was heated and stirred at 60°C for 6h under argon protection and light protection. After stirring, 30mL of ethanol was added, the mixture was centrifuged, washed, and dried under vacuum to obtain intermediate product 2.

[0067] Q3: Wash 2g of polyethylene with 10mL of acetone, dry it, and then treat it with plasma. The plasma treatment process is as follows: treat with plasma etching at 80W for 40s, then immerse the treated polyethylene in a 1mol / L sodium chloride solution containing 0.3g of intermediate product 2 for 10min, take it out, dry it, irradiate it for 60min, wash it with 0.1mol / L sodium chloride solution, and then wash it with deionized water to obtain the modified biofilm.

[0068] This embodiment discloses a method for preparing a composite adsorbent, including the following steps:

[0069] S1: Dissolve 2.18g of copper nitrate trihydrate in 30mL of deionized water to obtain a copper nitrate trihydrate solution. Then, dissolve 1.25g of trimellitic acid in 20mL of anhydrous ethanol by sonication to obtain a trimellitic acid solution. Add the copper nitrate trihydrate solution and the trimellitic acid solution to a container and mix them. After reacting at 130℃ for 24h, a solid-liquid mixture is obtained. Centrifuge at 6000rpm for 8min, sonicate the precipitate for 6min, and dry at 70℃ for 12h to obtain intermediate product A.

[0070] S2: 1g of polyethyleneimine and 1.6g of styrene-maleic anhydride copolymer were dissolved in 20mL of dimethyl sulfoxide to obtain polyethyleneimine solution and styrene-maleic anhydride copolymer solution, respectively. Then, the styrene-maleic anhydride copolymer solution was added dropwise to the polyethyleneimine solution and reacted for 24h. The mixture was dialyzed in deionized water using a cellulose dialysis membrane for 24h, then freeze-dried under vacuum and pulverized to obtain intermediate product B.

[0071] S3: Disperse 6g of intermediate product B in 20mL of deionized water by ultrasonication for 10min, then add 9g of intermediate product A, stir for 8h, and vacuum dry at 80℃ for 12h to obtain the composite adsorbent.

[0072] See Figure 1 As shown in the figure, this embodiment discloses a wastewater recovery method in a silane coupling agent production workshop, including the following steps:

[0073] Step (1): First, the wastewater from the silane coupling agent production workshop is discharged into the first equalization tank through a screen. Sulfuric acid or sodium hydroxide is added to the first equalization tank to adjust the pH to 7. Then, the wastewater in the first equalization tank is pumped to the flotation tank for flotation to obtain pretreated wastewater.

[0074] Step (2): The pretreated wastewater flows into the four-effect evaporation system by gravity. The four-effect evaporation system operates in a vacuum environment. The pretreated wastewater is first sent into the first evaporator. Fresh steam is sent in at the same time to heat the pretreated wastewater. The generated secondary steam is introduced into the second evaporator so that the evaporation temperature of the wastewater in the second evaporator is lower than that in the first evaporator. This process is carried out in sequence to the fourth evaporator for evaporation and desalination to obtain concentrated wastewater. The concentrated wastewater is pumped to the second equalization tank for cooling. After flowing through the coagulation sedimentation tank, it is pumped to the third equalization tank to obtain the equalization tank effluent.

[0075] Step (3): The effluent from the equalization tank enters the biological treatment unit containing the modified biofilm to obtain biologically treated wastewater. Then, the biologically treated wastewater is pumped to the fourth equalization tank containing the composite adsorbent to obtain recyclable water.

[0076] Example 4

[0077] This embodiment discloses a method for preparing a modified biofilm, including the following steps:

[0078] Q1: Dissolve 0.25 g of 4-azidoaniline hydrochloride in 10 mL of diethyl ether, then add 15 mL of 5 wt% sodium bicarbonate solution, stir in the dark at room temperature for 15 min, then separate the diethyl ether layer, add 0.115 mL of methacrylic acid, 0.32 g of N,N'-dicyclohexylcarboimide and 0.02 g of 4-dimethylaminopyridine to the diethyl ether layer, stir in the dark for 12 h, filter, first extract with 5 wt% sodium bicarbonate solution, then extract with deionized water, dry, and rotary evaporate to obtain intermediate product 1;

[0079] Q2: 2.5g of intermediate product 1, 0.006g of azobisisobutyronitrile and 2.5g of N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine were added to 3mL of ethanol solution with a volume fraction of 33vt%. The mixture was heated and stirred at 60°C for 6h under argon protection and light protection. After stirring, 25mL of ethanol was added, the mixture was centrifuged, washed, and dried under vacuum to obtain intermediate product 2.

[0080] Q3: Wash 2g of polyethylene with 10mL of acetone, dry it, and then treat it with plasma. The plasma treatment process is as follows: treat with plasma etching at 80W for 40s, then immerse the treated polyethylene in a 1mol / L sodium chloride solution containing 0.3g of intermediate product 2 for 10min, take it out, dry it, irradiate it for 60min, wash it with 0.1mol / L sodium chloride solution, and then wash it with deionized water to obtain the modified biofilm.

[0081] This embodiment discloses a method for preparing a composite adsorbent, including the following steps:

[0082] S1: Dissolve 1.64g of copper nitrate trihydrate in 22mL of deionized water to obtain a copper nitrate trihydrate solution. Then, dissolve 0.91g of trimellitic acid in 28mL of anhydrous ethanol by sonication to obtain a trimellitic acid solution. Add the copper nitrate trihydrate solution and the trimellitic acid solution to a container and mix them. After reacting at 130℃ for 24h, a solid-liquid mixture is obtained. Centrifuge at 6000rpm for 8min, sonicate the precipitate for 6min, and dry at 70℃ for 12h to obtain intermediate product A.

[0083] S2: Dissolve 0.6g of polyethyleneimine and 1g of styrene-maleic anhydride copolymer in 20mL of dimethyl sulfoxide to obtain polyethyleneimine solution and styrene-maleic anhydride copolymer solution respectively. Then, add the styrene-maleic anhydride copolymer solution dropwise to the polyethyleneimine solution and react for 24h. Dialyze the solution in deionized water using a cellulose dialysis membrane for 24h, freeze-dry under vacuum, and pulverize to obtain intermediate product B.

[0084] S3: Disperse 4.5g of intermediate product B in 12mL of deionized water by ultrasonication for 10min, then add 8g of intermediate product A, stir for 8h, and vacuum dry at 80℃ for 12h to obtain the composite adsorbent.

[0085] See Figure 1 As shown in the figure, this embodiment discloses a wastewater recovery method in a silane coupling agent production workshop, including the following steps:

[0086] Step (1): First, the wastewater from the silane coupling agent production workshop is discharged into the first equalization tank through a screen. Sulfuric acid or sodium hydroxide is added to the first equalization tank to adjust the pH to 7. Then, the wastewater in the first equalization tank is pumped to the flotation tank for flotation to obtain pretreated wastewater.

[0087] Step (2): The pretreated wastewater flows into the four-effect evaporation system by gravity. The four-effect evaporation system operates in a vacuum environment. The pretreated wastewater is first sent into the first evaporator. Fresh steam is sent in at the same time to heat the pretreated wastewater. The generated secondary steam is introduced into the second evaporator so that the evaporation temperature of the wastewater in the second evaporator is lower than that in the first evaporator. This process is carried out in sequence to the fourth evaporator for evaporation and desalination to obtain concentrated wastewater. The concentrated wastewater is pumped to the second equalization tank for cooling. After flowing through the coagulation sedimentation tank, it is pumped to the third equalization tank to obtain the equalization tank effluent.

[0088] Step (3): The effluent from the equalization tank enters the biological treatment unit containing the modified biofilm to obtain biologically treated wastewater. Then, the biologically treated wastewater is pumped to the fourth equalization tank containing the composite adsorbent to obtain recyclable water.

[0089] Comparative Example 1

[0090] Compared with Example 1, Comparative Example 1 did not add N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine during the preparation of the modified biofilm, and all other conditions remained unchanged.

[0091] Comparative Example 2

[0092] Compared with Example 1, Comparative Example 2 did not add styrene-maleic anhydride copolymer during the preparation of the composite adsorbent, while all other conditions remained unchanged.

[0093] Comparative Example 3

[0094] Compared with Example 1, Comparative Example 3 did not add modified biofilm in the wastewater recovery method of the silane coupling agent production workshop, and all other conditions remained unchanged.

[0095] Comparative Example 4

[0096] Compared with Example 1, Comparative Example 4 did not add composite adsorbent in the wastewater recovery method of the silane coupling agent production workshop, and all other conditions remained unchanged.

[0097] Wastewater from the silane coupling agent production workshop was treated using Examples 1-4 and Comparative Examples 1-4. The concentrations of pollutants in the wastewater before and after treatment were measured. The removal rate was calculated as follows: [(C...] 前 -C 后 ) / C 前The percentage of wastewater treated was 100%, where the chemical oxygen demand (COD) was determined according to GB / T 15456-2019, the five-day biochemical oxygen demand (BOD5) was determined according to HJ 505-2009, the suspended solids (SS) were determined according to GB 11901-1989, the total nitrogen (TN) was determined according to HJ 636-2012, the total organic carbon (TOC) was determined according to GB / T 32116-2015, the methanol was determined according to DB61 / T 971-2015, and the treatment of whether the treated wastewater met the secondary discharge standard was determined according to GB 8978-1996. The test results are shown in Table 1.

[0098] Table 1

[0099]

[0100] As shown in Table 1, the test results demonstrate that the methods described in Examples 1-4 of this invention can effectively reduce the pollutant content in the wastewater from the silane coupling agent production workshop. A comparison between Comparative Example 1 and Examples 1-4 shows that adding N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine can effectively reduce the pollutant content in the wastewater from the silane coupling agent production workshop; a comparison between Comparative Example 2 and Examples 1-4 shows that adding styrene-maleic anhydride copolymer can effectively reduce the pollutant content in the wastewater from the silane coupling agent production workshop; a comparison between Comparative Example 3 and Examples 1-4 shows that adding modified biofilm can effectively reduce the pollutant content in the wastewater from the silane coupling agent production workshop; and a comparison between Comparative Example 4 and Examples 1-4 shows that adding composite adsorbent can effectively reduce the pollutant content in the wastewater from the silane coupling agent production workshop.

[0101] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0102] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for wastewater recovery in a silane coupling agent production workshop, characterized in that, Includes the following steps: Step (1): First, the wastewater from the silane coupling agent production workshop is discharged into the first equalization tank through a screen, and then the wastewater in the first equalization tank is pumped to the flotation tank for flotation to obtain pretreated wastewater. Step (2): The pretreated wastewater flows into the four-effect evaporation system by gravity for evaporation and desalination to obtain concentrated wastewater. The concentrated wastewater is pumped to the second equalization tank for cooling, and after flowing through the coagulation sedimentation tank, it is pumped to the third equalization tank to obtain the equalization tank effluent. Step (3): The effluent from the equalization tank enters the biological treatment unit to obtain biologically treated wastewater. Then, the biologically treated wastewater is pumped to the fourth equalization tank containing composite adsorbent to obtain recyclable water. The biological treatment unit contains a modified biofilm, and the method for preparing the modified biofilm includes the following steps: Q1: Dissolve 4-azidoaniline hydrochloride in diethyl ether, then add sodium bicarbonate solution, stir under light at room temperature, then separate the diethyl ether layer, add methacrylic acid, N,N'-dicyclohexylcarboimide and 4-dimethylaminopyridine to the diethyl ether layer, stir under light, filter, extract, dry, and rotary evaporate to obtain intermediate product 1; Q2: Add intermediate product 1, azobisisobutyronitrile and N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine to an ethanol solution, heat and stir under argon protection, and then add ethanol, centrifuge, wash, and vacuum dry to obtain intermediate product 2. Q3: The polyethylene was washed with acetone, dried, and then treated with plasma. The treated polyethylene was then immersed in a sodium chloride solution containing intermediate product 2. After immersion, it was taken out, dried, irradiated, and washed to obtain a modified biofilm. The preparation method of the composite adsorbent includes the following steps: S1: Dissolve copper nitrate trihydrate in deionized water to obtain copper nitrate trihydrate solution. Then, sonicately dissolve trimellitic acid in anhydrous ethanol to obtain trimellitic acid solution. Add copper nitrate trihydrate solution and trimellitic acid solution to a container for mixing. After heating and reacting, a solid-liquid mixture is obtained. Centrifuge, ultrasonically clean the precipitate, and dry it to obtain intermediate product A. S2: Polyethyleneimine and styrene-maleic anhydride copolymer were dissolved in dimethyl sulfoxide to obtain polyethyleneimine solution and styrene-maleic anhydride copolymer solution, respectively. Then, the styrene-maleic anhydride copolymer solution was added dropwise to the polyethyleneimine solution, reacted, dialyzed, freeze-dried under vacuum, and pulverized to obtain intermediate product B. S3: Disperse intermediate product B in deionized water using ultrasound, then add intermediate product A, stir, and vacuum dry to obtain the composite adsorbent.

2. The wastewater recovery method for a silane coupling agent production workshop according to claim 1, characterized in that, In step (1), sulfuric acid or sodium hydroxide is added to the first conditioning tank to adjust the pH to 7-7.

2.

3. The wastewater recovery method for a silane coupling agent production workshop according to claim 1, characterized in that, In step (2), the four-effect evaporation system operates in a vacuum environment. The pretreated wastewater is first sent into the first evaporator, and fresh steam is simultaneously sent in to heat the pretreated wastewater. The generated secondary steam is introduced into the second evaporator, so that the evaporation temperature of the wastewater in the second evaporator is lower than that in the first evaporator. This process is repeated until the fourth evaporator is reached, resulting in concentrated wastewater.

4. The wastewater recovery method for a silane coupling agent production workshop according to claim 1, characterized in that, In Q1, the ratio of 4-azidoaniline hydrochloride, sodium bicarbonate solution, methacrylic acid, N,N'-dicyclohexylcarboimide, and 4-dimethylaminopyridine is (0.15-0.45)g:(10-30)mL:(0.077-0.231)mL:(0.21-0.63)g:(0.01-0.04)g. The sodium bicarbonate solution has a weight fraction of 5wt%. The stirring time is 10-15 min at room temperature under light, and the stirring time is 10-12 h under light. Extraction is first performed with 5wt% sodium bicarbonate solution, followed by extraction with deionized water.

5. The wastewater recovery method for a silane coupling agent production workshop according to claim 1, characterized in that, In Q2, the ratio of intermediate product 1, azobisisobutyronitrile, N-(3-sulfopropyl)-N-methylpropenoxyethyl-N,N-dimethylammonium betaine, ethanol solution, and ethanol is (1-3)g:(0.004-0.012)g:(2-5)g:(2-6)mL:(5-30)mL, the volume fraction of the ethanol solution is 33vt%, the heating and stirring temperature is 55-60℃, and the time is 5-6h.

6. The wastewater recovery method for a silane coupling agent production workshop according to claim 1, characterized in that, In Q3, the plasma treatment process is as follows: plasma etching is performed at 80W for 40s, the concentration of sodium chloride solution is 1mol / L, the soaking time is 5-10min, the irradiation time is 40-60min, and the first washing is performed with 0.1mol / L sodium chloride solution, followed by deionization washing.

7. The wastewater recovery method for a silane coupling agent production workshop according to claim 1, characterized in that, In step S1, the ratio of copper nitrate trihydrate, deionized water, trimesic acid, and anhydrous ethanol is (1.45-2.18)g:(20-30)mL:(0.84-1.25)g:(20-30)mL. The reaction temperature is 120-130℃, the reaction time is 20-24h, the centrifugation speed is 5000-6000rpm, the centrifugation time is 5-8min, the ultrasonic cleaning time is 3-6min, the drying temperature is 60-70℃, and the drying time is 10-12h.

8. The wastewater recovery method for a silane coupling agent production workshop according to claim 1, characterized in that, In S2, the mass ratio of polyethyleneimine to styrene-maleic anhydride copolymer is (0.5-1):(0.8-1.6), the reaction time is 22-24 h, and the dialysis process is: dialysis in deionized water using a cellulose dialysis membrane for 24 h.

9. The wastewater recovery method for a silane coupling agent production workshop according to claim 1, characterized in that, In S3, the ratio of intermediate product B, deionized water and intermediate product A is (4-6)g:(10-20)mL:(6-9)g, the ultrasonic dispersion time is 10-15min, the stirring time is 6-8h, the vacuum drying temperature is 60-80℃, and the vacuum drying time is 10-12h.

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