A method for improving the biodegradability of sorbic acid wastewater

Abstract

The application discloses a treatment method for improving the biodegradability of sorbic acid wastewater and belongs to the field of chemical technology. The application specifically comprises the following steps: filtering the wastewater containing sorbic acid first, distilling low-boiling-point organic matters such as ethanol in the wastewater at 100-102 DEG C, and evaporating a small amount of water at the same time; uniformly mixing aluminum silicate, oxide and a binder at a ratio of 5-10:1:5-8, vacuum-drying after suction filtration, roasting and activating after grinding into 50-100 meshes, roasting at a temperature of 200-400 DEG C for 2-4 hours, and obtaining the recyclable solid catalyst after the temperature is reduced to normal temperature; the wastewater passes through a column-tube type reactor provided with the solid catalyst, the residence time is 4-10 hours, the temperature of the wastewater is maintained at 140-160 DEG C, and the reaction pressure is 0.4-0.7 MPa; after the reaction, the wastewater is cooled, and is layered after standing; the content of sorbic acid in the upper water layer is 0.008-0.030%, and the removal rate of sorbic acid in the wastewater reaches 95-98%.

Description

Technical Field

[0001] The invention relates to a treatment method for improving the biodegradability of sorbic acid wastewater, and belongs to the field of chemical industry. Background Art

[0002] Sorbic acid is an unsaturated fatty acid with conjugated double bonds. Like naturally occurring unsaturated acids, it participates in human metabolism and is oxidized to carbon dioxide and water. It is currently the lowest metabolic toxicity preservative in industrial production. Sorbic acid is an acidic preservative with significant inhibitory effects on molds, aerobic bacteria, and yeasts. It readily binds to thiol groups in microbial enzyme systems, disrupting many important enzyme systems and achieving its antibacterial and preservative properties.

[0003] Sorbic acid production wastewater is large in volume, complex in composition, high in organic matter concentration, and poorly biodegradable. Currently, domestic treatment of sorbic acid production wastewater mostly utilizes a combined pretreatment-biological treatment process. This involves neutralization, sedimentation, flocculation, dilution, and membrane separation to remove most of the organic matter and sorbic acid in the wastewater before biochemical treatment.

[0004] Patent CN1168671C reports a method for treating and recovering washing wastewater from sorbic acid production. This method uses a resin to absorb sorbic acid from the wastewater, reducing the COD content and preparing it for subsequent biochemical treatment. Patent CN114684956A reports a membrane separation method for recovering sorbic acid from sorbic acid wastewater. Ultrafiltration and nanofiltration devices are used to separate the sorbic acid concentrate from clean water, allowing for resource utilization. These technologies all extract and separate sorbic acid from wastewater for recycling, which is somewhat cumbersome and costly. Direct biochemical treatment also presents challenges. This technology, based on the properties of sorbic acid, converts it into a water-insoluble polymer in the wastewater, eliminating the need for additional reagents and equipment and reducing treatment costs. Summary of the Invention

[0005] In the present invention, sorbic acid in wastewater self-polymerizes under the action of a catalyst and is converted into a high polymer, thereby forming a layer with water, thereby effectively reducing the content of sorbic acid in the wastewater and reducing the pressure of the wastewater entering subsequent biochemical treatment.

[0006] The present invention provides a method for treating sorbic acid wastewater, which comprises the following steps:

[0007] (1) Filtering the sorbic acid wastewater to remove tar and other insoluble substances;

[0008] (2) distilling the filtered wastewater until the top temperature reaches 98-102°C and then stopping distillation;

[0009] (3) adding a solid catalyst to the wastewater treated in step (2), with a reaction time of 4 to 10 hours, a reaction temperature of 140 to 160° C., and a pressure condition of 0.4 to 0.7 MPa, wherein the solid catalyst is an aluminum silicate and an oxide, and the oxide is one or more of titanium dioxide, silicon dioxide, and zirconium dioxide;

[0010] (4) After the reaction is completed, the pressure is released, the mixture is cooled, and the mixture is allowed to stand to obtain a wastewater treatment liquid from which sorbic acid has been removed.

[0011] In one embodiment, in step (1), the filtration is performed by using any one of porous activated carbon columns, resins, graphene, and electrosorption to remove tar and other insoluble substances before filtration.

[0012] In one embodiment, in step (2), distillation is stopped until the top temperature reaches 102°C.

[0013] In one embodiment, in step (2), the sorbic acid content in the wastewater after distillation is 0.4-0.6%.

[0014] In one embodiment, the preparation method of the solid catalyst described in step (3) is to mix aluminum silicate, oxide and binder in a ratio of 4-11:0.5-1.5:4-9, filter, roast and activate, and obtain the obtained product. The binder includes but is not limited to water; further, the ratio is 5-10:1:5-8.

[0015] In one embodiment, the oxide is selected from one or more of titanium dioxide, silicon dioxide, and zirconium dioxide.

[0016] In one embodiment, the binder is one or more of water, methanol, and methyltrimethoxysilane.

[0017] In one embodiment, the filtration is followed by grinding and sieving to obtain solid particles with a particle size of 50 to 100 meshes, which are then calcined and activated; further, the particle size is 50 meshes.

[0018] In one embodiment, the calcination activation is performed at a temperature of 200 to 400° C. for 2 to 4 hours; further, the calcination activation is performed at 400° C. for 4 hours.

[0019] In one embodiment, in step (3), the solid catalyst is prepared by stirring and uniformly mixing aluminum silicate, oxide and binder in a mass ratio of 5:1:5, filtering and grinding to obtain solid particles with a particle size of 50 mesh, calcining the solid particles at 400°C for 2h, and cooling to obtain the solid catalyst; the binder includes but is not limited to deionized water.

[0020] In one embodiment, the solid catalyst is reactivated after 2 to 4 weeks of use.

[0021] In one embodiment, in step (3), after adding the solid catalyst to the wastewater treated in step (2), the reaction conditions are controlled to be a temperature of 140 to 160° C., a pressure of 0.4 to 0.7 MPa, and a reaction time of 4 to 10 h; further, the reaction conditions are controlled to be a temperature of 160° C., a pressure of 0.7 MPa, and a reaction time of 10 h.

[0022] In one embodiment, in step (3), a solid catalyst is added to the wastewater treated in step (2), and the solid catalyst is loaded into a shell-and-tube reactor after activation.

[0023] In one embodiment, the filling height of the solid catalyst is 80% of the length of the reaction tube of the shell-and-tube reactor.

[0024] In one embodiment, the cooling in step (4) is to cool the wastewater to 25°C via a heat exchanger.

[0025] In one embodiment, in step (4), the sorbic acid content in the upper aqueous layer after standing and stratification is 0.008-0.030%.

[0026] In one embodiment, the method comprises the steps of:

[0027] (1) The sorbic acid wastewater is passed through a carbon column to remove tar and other insoluble substances therein by adsorption, and then filtered;

[0028] (2) distilling the filtered wastewater to remove most of the low-boiling-point organic matter such as ethanol in the wastewater until the top temperature reaches 102°C and the distillation is stopped;

[0029] (3) Preparation and activation of solid catalyst: Aluminum silicate and titanium dioxide are mixed with deionized water as a binder in a ratio of 5-10:1:5-8, filtered, dried and ground, and calcined at high temperature for activation;

[0030] (4) continuously passing the wastewater treated in step (2) through the activated solid catalyst for a residence time of 4 to 10 hours, a reaction temperature of 140 to 160° C., and a reaction pressure of 0.4 to 0.7 MPa;

[0031] (5) After the reaction is completed, the liquid phase is cooled to 20-25°C through a heat exchanger and allowed to stand for separation. The upper water layer is sent to the biochemical system for treatment, and the lower polymer layer is sent to incineration for treatment.

[0032] The present invention also provides application of the above treatment method in treating sorbic acid wastewater, and the removal rate of sorbic acid in the wastewater reaches 95-98%.

[0033] The present invention effectively promotes the self-polymerization conversion of sorbic acid by controlling the amount of catalyst, reaction temperature, reaction pressure and reaction time during the reaction process, and separates the sorbic acid polymer from wastewater through liquid separation treatment, further reducing the sorbic acid content in the wastewater and improving the biochemical treatment capacity.

[0034] Beneficial effects

[0035] (1) The method provided by the present invention mainly targets the chemical structure of sorbic acid. By controlling the polymerization conditions (solid catalyst prepared by aluminum silicate and titanium dioxide and binder deionized water in a ratio of 5-10:1:5-8, reaction temperature of 140-160°C, reaction time of 4-10 hours and reaction pressure of 0.4-0.7 MPa), it is converted into a high polymer under certain conditions, thereby separating it from the water layer, achieving the effect of removing sorbic acid, reducing the sorbic acid content in wastewater, and thereby improving the biodegradability of the wastewater;

[0036] (2) The sorbic acid content in the wastewater treated by the present invention is only 0.008-0.030%, and the removal rate of sorbic acid can reach 95-98%. DETAILED DESCRIPTION

[0037] The following is a specific implementation method of improving the biodegradability of sorbic acid wastewater provided by the present invention.

[0038] 1. The sorbic acid wastewater involved in the following examples is production wastewater with an initial COD of 180,000 to 200,000 mg / L and an ethanol content of 3.5 to 4%. After treatment with the present invention, the COD is 90,000 to 120,000 mg / L and the ethanol content is 0.5 to 0.8%.

[0039] 2. The detection methods / calculation formulas involved in the following embodiments:

[0040] Sorbic acid content was determined by high performance liquid chromatography

[0041] Instruments and equipment: Liquid chromatograph;

[0042] Chromatographic column: Agilent Eclipse XDB-C18;

[0043] Test steps: Weigh approximately 0.15g of sample, dissolve it in a solvent by ultrasonication, dilute with water into a 100mL volumetric flask, and filter through a 0.45μm filter before injection. Turn on the chromatograph. After all instrument operating conditions stabilize, inject the sample solution into the injection valve using a microsyringe. After all components have been discharged, analyze the results using a chromatographic workstation or integrator.

[0044] The calculation formula for sorbic acid removal rate is:

[0045]

[0046] Example 1: A treatment method for improving the biodegradability of sorbic acid wastewater

[0047] (1) The sorbic acid wastewater was filtered through a filter paper after removing tar and other insoluble substances therein by adsorption through a porous activated carbon column;

[0048] (2) The supernatant of the filtered wastewater was subjected to distillation through a distillation column until the top temperature reached 102°C to stop the distillation, so as to separate and remove most of the low-boiling-point organic substances (about 3% of which was ethanol) therein. After the distillation, the sorbic acid content in the wastewater was measured to be 0.60%;

[0049] (3) Preparation and activation of the solid catalyst:

[0050] The aluminum silicate, titanium dioxide nanopowder, and binder (deionized water) were stirred and mixed uniformly at a mass ratio of 5:1:5, and then filtered through a Buchner funnel and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2h to complete the activation and cool to room temperature;

[0051] (4) The wastewater treated in step (2) was added to a shell-and-tube reactor containing the solid catalyst prepared in step (3) after activation, and the solid catalyst was loaded to a height of 80% of the length of the reaction tube of the shell-and-tube reactor. The temperature in the shell-and-tube reactor was controlled at 140°C, the pressure was 0.4 MPa, and the wastewater residence time was 10h;

[0052] (5) After the reaction was completed, the pressure was released, the wastewater was cooled to 25°C through a heat exchanger, and then was allowed to stand and separate into layers. The sorbic acid content in the water layer was measured to be 0.018%, and the final sorbic acid removal rate was calculated to be 97.0% based on the residual sorbic acid content in the wastewater.

[0053] Example 2: A treatment method for improving the biodegradability of sorbic acid wastewater

[0054] Referring to Example 1, the only difference is that the polymerization temperature is adjusted to 160°C and the pressure is 0.7 MPa. The specific steps are as follows:

[0055] (1) The sorbic acid wastewater was filtered through a filter paper after removing tar and other insoluble substances therein by adsorption through a porous activated carbon column;

[0056] (2) The supernatant of the filtered wastewater was subjected to distillation through a distillation column until the top temperature reached 102°C to stop the distillation, so as to separate and remove most of the low-boiling-point organic substances (about 3% of which was ethanol) therein. After the distillation, the sorbic acid content in the wastewater was measured to be 0.59%;

[0057] (3) Preparation and activation of the solid catalyst:

[0058] Aluminum silicate, titanium dioxide nanopowder and binder (deionized water) were stirred and mixed in a mass ratio of 5:1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain;

[0059] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the length of the reaction tube of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 160° C., the pressure to 0.7 MPa, and the wastewater residence time to 10 h;

[0060] (5) After the reaction is completed, the pressure is released, and the wastewater is cooled to 25°C through a heat exchanger and allowed to stand for separation. The sorbic acid content in the water layer is measured to be 0.010%. The sorbic acid removal rate is finally calculated to be 98.3% based on the residual sorbic acid content in the wastewater.

[0061] Example 3: Treatment method for improving the biodegradability of sorbic acid wastewater

[0062] Referring to Example 1, the only difference is that the polymerization reaction time is adjusted to 6 hours. The specific steps are as follows:

[0063] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0064] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.59%;

[0065] (3) Preparation and activation of solid catalyst:

[0066] Aluminum silicate, titanium dioxide nanopowder and binder (deionized water) were stirred and mixed in a mass ratio of 5:1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain;

[0067] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the length of the reaction tube of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 6 h;

[0068] (5) After the reaction, the pressure was released, and the wastewater was cooled to 25°C by a heat exchanger. After standing and separating, the content of sorbic acid in the water layer was 0.025%, and the removal rate of sorbic acid was 95.8%.

[0069] Example 4: A treatment method for improving the biodegradability of sorbic acid wastewater

[0070] Referring to Example 1, the difference is only that the catalyst activation condition is adjusted to calcination at 400°C for 4h, and the specific steps are as follows:

[0071] (1) The sorbic acid wastewater was filtered by a filter paper after removing tar and other insoluble substances by a porous activated carbon column;

[0072] (2) The supernatant of the filtered wastewater was distilled by a rectifying column until the top temperature reached 102°C to stop distillation. After removing most of the low-boiling-point organic substances (about 3% of ethanol) in it, the content of sorbic acid in the wastewater after distillation was measured to be 0.55%;

[0073] (3) Preparation and activation of solid catalyst:

[0074] The aluminum silicate, titanium dioxide nano powder and binder (deionized water) were stirred and mixed uniformly at a mass ratio of 5:1:5. After suction filtration by a Buchner funnel, the solid particles with a particle size of 50 mesh were obtained by grinding and sieving. The solid particles were calcined at 400°C for 4h, and then cooled to room temperature to obtain the solid catalyst;

[0075] (4) The wastewater treated in step (2) was added to a tubular reactor containing the solid catalyst prepared in step (3) after activation (the solid catalyst was packed to a height of 80% of the length of the reaction tube of the tubular reactor). The temperature in the tubular reactor was controlled at 140°C, the pressure was 0.4MPa, and the wastewater residence time was 10h;

[0076] (5) After the reaction, the pressure was released, and the wastewater was cooled to 25°C by a heat exchanger. After standing and separating, the content of sorbic acid in the water layer was 0.022%, and the removal rate of sorbic acid was 96.0%.

[0077] Example 5: A treatment method for improving the biodegradability of sorbic acid wastewater

[0078] Referring to Example 1, the difference is only that the catalyst preparation condition is adjusted, and the specific steps are as follows:

[0079] (1) The sorbic acid wastewater was filtered by a filter paper after removing tar and other insoluble substances by a porous activated carbon column;

[0080] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.56%;

[0081] (3) Preparation and activation of solid catalyst:

[0082] Aluminum silicate, titanium dioxide nanopowder and binder (deionized water) were stirred and mixed in a mass ratio of 10:1:8, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain;

[0083] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the reaction tube length of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 10 h;

[0084] (5) After the reaction is completed, the pressure is released, and the wastewater is cooled to 25°C through a heat exchanger and allowed to stand for separation. The sorbic acid content in the water layer is measured to be 0.028%. The sorbic acid removal rate is finally calculated to be 95.0% based on the residual sorbic acid content in the wastewater.

[0085] Example 6: Treatment method for improving the biodegradability of sorbic acid wastewater

[0086] Referring to Example 1, the only difference is that the titanium dioxide in Example 1 is adjusted to zirconium dioxide. The specific steps are as follows:

[0087] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0088] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.55%;

[0089] (3) Preparation and activation of solid catalyst:

[0090] Aluminum silicate, zirconium dioxide nanopowder and binder (deionized water) were stirred and mixed in a mass ratio of 5:1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain;

[0091] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the reaction tube length of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 10 h;

[0092] (5) After the reaction is completed, the pressure is released, and the wastewater is cooled to 25°C through a heat exchanger and allowed to stand for separation. The sorbic acid content in the water layer is measured to be 0.018%. The sorbic acid removal rate is finally calculated to be 96.7% based on the residual sorbic acid content in the wastewater.

[0093] Example 7: Treatment method for improving the biodegradability of sorbic acid wastewater

[0094] Referring to Example 1, the only difference is that the titanium dioxide in Example 1 is adjusted to silicon dioxide. The specific steps are as follows:

[0095] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0096] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.56%;

[0097] (3) Preparation and activation of solid catalyst:

[0098] Aluminum silicate, zirconium dioxide nanopowder and binder (deionized water) were stirred and mixed in a mass ratio of 5:1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain;

[0099] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the reaction tube length of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 10 h;

[0100] (5) After the reaction is completed, the pressure is released, and the wastewater is cooled to 25°C through a heat exchanger and allowed to stand for separation. The sorbic acid content in the water layer is measured to be 0.018%. The sorbic acid removal rate is finally calculated to be 96.9% based on the residual sorbic acid content in the wastewater.

[0101] Comparative Example 1: Treatment method for improving the biodegradability of sorbic acid wastewater

[0102] Referring to Example 1, the only difference is that the polymerization reaction temperature is adjusted to 100° C. and the pressure is adjusted to 0.3 MPa. The specific steps are as follows:

[0103] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0104] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.55%;

[0105] (3) Preparation and activation of solid catalyst:

[0106] Aluminum silicate, titanium dioxide nanopowder and binder (deionized water) were stirred and mixed in a mass ratio of 5:1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain;

[0107] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the reaction tube length of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 100° C., the pressure to 0.3 MPa, and the wastewater residence time to 10 h;

[0108] (5) After the reaction is completed, the pressure is released, and the wastewater is cooled to 25°C through a heat exchanger and allowed to stand for separation. The sorbic acid content in the water layer is measured to be 0.46%. The sorbic acid removal rate is finally calculated to be 16.4% based on the residual sorbic acid content in the wastewater.

[0109] Comparative Example 2: Treatment method for improving the biodegradability of sorbic acid wastewater

[0110] Referring to Example 1, the only difference is that the polymerization reaction time is adjusted to 2 hours. The specific steps are as follows:

[0111] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0112] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.50%;

[0113] (3) Preparation and activation of solid catalyst:

[0114] Aluminum silicate, titanium dioxide nanopowder and binder (deionized water) were stirred and mixed in a mass ratio of 5:1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain;

[0115] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the length of the reaction tube of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 2 h;

[0116] (5) After the reaction is completed, the pressure is released, and the wastewater is cooled to 25°C through a heat exchanger and allowed to stand for separation. The sorbic acid content in the water layer is measured to be 0.28%. The sorbic acid removal rate is finally calculated to be 44.0% based on the residual sorbic acid content in the wastewater.

[0117] Comparative Example 3: Treatment method for improving the biodegradability of sorbic acid wastewater

[0118] Referring to Example 1, the only difference is that the titanium dioxide in Example 1 is adjusted to zinc oxide, and the specific steps are as follows:

[0119] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0120] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.58%;

[0121] (3) Preparation and activation of solid catalyst:

[0122] Aluminum silicate, zinc oxide and a binder (deionized water) were stirred and mixed in a mass ratio of 5:1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain the product;

[0123] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the reaction tube length of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 10 h;

[0124] (5) After the reaction is completed, the pressure is released, and the wastewater is cooled to 25°C through a heat exchanger and allowed to stand for separation. The sorbic acid content in the water layer is measured to be 0.154%. The sorbic acid removal rate is finally calculated to be 73.4% based on the residual sorbic acid content in the wastewater.

[0125] Comparative Example 4: Treatment method for improving the biodegradability of sorbic acid wastewater

[0126] Referring to Example 1, the only difference is that the aluminum silicate in Example 1 is adjusted to magnesium silicate. The specific steps are as follows:

[0127] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0128] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.58%;

[0129] (3) Preparation and activation of solid catalyst:

[0130] Magnesium silicate, zirconium dioxide nanopowder and binder (deionized water) were stirred and mixed in a mass ratio of 5:1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain;

[0131] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the reaction tube length of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 10 h;

[0132] (5) After the reaction is completed, the pressure is released and the wastewater is cooled to 25°C through a heat exchanger. The wastewater is allowed to stand for separation and the sorbic acid content in the water layer is measured to be 0.219%. The sorbic acid removal rate is finally calculated to be 62.3% based on the residual sorbic acid content in the wastewater.

[0133] Comparative Example 5: Treatment method for improving the biodegradability of sorbic acid wastewater

[0134] Referring to Example 1, the difference is that the aluminum silicate in Example 1 is omitted and only titanium dioxide is used. The specific steps are as follows:

[0135] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0136] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.56%;

[0137] (3) Preparation and activation of solid catalyst:

[0138] The zirconium dioxide nanopowder and the binder (deionized water) were stirred and mixed in a mass ratio of 1:5, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2h and cooled to room temperature to obtain the product;

[0139] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the reaction tube length of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 10 h;

[0140] (5) After the reaction is completed, the pressure is released, and the wastewater is cooled to 25°C through a heat exchanger and allowed to stand for separation. The sorbic acid content in the water layer is measured to be 0.242%. The sorbic acid removal rate is finally calculated to be 56.7% based on the residual sorbic acid content in the wastewater.

[0141] Comparative Example 6: Treatment method for improving the biodegradability of sorbic acid wastewater

[0142] Referring to Example 1, the difference is that the titanium dioxide in Example 1 is omitted and only aluminum silicate is used. The specific steps are as follows:

[0143] (1) Sorbic acid wastewater is adsorbed on a porous activated carbon column to remove tar and other insoluble substances, and then filtered with filter paper;

[0144] (2) The supernatant of the filtered wastewater was distilled through a distillation tower until the top temperature reached 102°C and the distillation was stopped to separate and remove most of the low-boiling point organic matter (including about 3% ethanol). After measurement, the sorbic acid content in the wastewater after distillation was 0.56%;

[0145] (3) Preparation and activation of solid catalyst:

[0146] Aluminum silicate and a binder (deionized water) were stirred and mixed uniformly in a mass ratio of 1:1, filtered through a Buchner funnel, and then ground and sieved into solid particles with a particle size of 50 mesh. The solid particles were calcined at 400°C for 2 hours and then cooled to room temperature to obtain the product;

[0147] (4) adding the wastewater treated in step (2) to a shell-and-tube reactor containing the activated solid catalyst prepared in step (3) (the solid catalyst filling height is 80% of the reaction tube length of the shell-and-tube reactor), controlling the temperature in the shell-and-tube reactor to 140° C., the pressure to 0.4 MPa, and the wastewater residence time to 10 h;

[0148] (5) After the reaction is completed, the pressure is released and the wastewater is cooled to 25°C through a heat exchanger. The wastewater is allowed to stand for separation and the sorbic acid content in the water layer is measured to be 0.267%. The sorbic acid removal rate is finally calculated to be 52.4% based on the residual sorbic acid content in the wastewater.

[0149] The method provided by the present invention mainly targets the chemical structure of sorbic acid. By controlling polymerization conditions (catalyst, reaction temperature, time and pressure), it is converted into a high polymer under certain conditions, thereby separating it from the water layer, achieving the effect of removing sorbic acid, reducing the sorbic acid content in wastewater, and thus improving the biodegradability of the wastewater.

[0150] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for treating sorbic acid wastewater, characterized in that, The method comprises the following steps: (1) Filter the sorbic acid wastewater to remove tar and other insoluble substances; (2) Distill the filtered wastewater until the top temperature reaches 100~102℃ and then stop distillation; (3) adding a solid catalyst to the wastewater treated in step (2), with a reaction time of 4 to 10 h, a reaction temperature of 140 to 160° C., and a pressure condition of 0.4 to 0.7 MPa, wherein the solid catalyst is an aluminum silicate and an oxide, and the oxide is one or more of titanium dioxide, silicon dioxide, and zirconium dioxide; The solid catalyst is prepared by mixing aluminum silicate, oxide, and a binder in a ratio of 5-10:1:5-8, filtering, and calcining to activate the mixture, wherein the binder is water; the calcination activation step is performed at a temperature of 200-400° C. for 2-4 hours; (4) After the reaction is completed, the pressure is released, the mixture is cooled, and the mixture is allowed to stand to obtain a wastewater treatment liquid from which sorbic acid has been removed.

2. The processing method according to claim 1, characterized in that The filtering is followed by grinding and screening to obtain solid particles with a particle size of 50-100 meshes, which are then calcined and activated.

3. The processing method according to claim 2, characterized in that The filtering step is followed by grinding and screening to obtain solid particles with a particle size of 50 meshes, which are then calcined and activated.

4. The processing method according to claim 3, characterized in that The calcination activation is performed at 400° C. for 4 h.

5. The processing method according to claim 1, characterized in that The filtration in step (1) is that the sorbic acid wastewater is adsorbed by a porous activated carbon column to remove tar and other insoluble substances therein and then filtered with filter paper.

6. The processing method according to claim 1, characterized in that In step (3), after adding the solid catalyst to the wastewater treated in step (2), the reaction conditions are controlled to be temperature 160° C., pressure 0.7 MPa, and reaction time 10 h.

7. The processing method according to claim 1, characterized in that In step (3), the solid catalyst is prepared by stirring and uniformly mixing aluminum silicate, oxide and binder in a mass ratio of 5:1:5, filtering and grinding and sieving to form solid particles with a particle size of 50 mesh, calcining the solid particles at 400°C for 2 hours, and cooling to obtain the solid catalyst; the binder is deionized water.

8. Use of the treatment method according to any one of claims 1 to 7 in treating sorbic acid wastewater, wherein the sorbic acid removal rate in the wastewater reaches 95-98%.

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