Method for extracting pyrolysis liquid and preparing modified bioplastic

Abstract

The invention discloses a method for extracting pyrolysis liquid and preparing modified bioplastics, which comprises the following steps: taking sludge subjected to filter pressing in a municipal sewage treatment plant, and adding water and NaOH to obtain stirred sludge; sealing the stirred sludge, raising the temperature to reach the temperature, standing and cooling to obtain a reactant; adding a diethyl ether-petroleum ether mixed solution into the reactant, separating and extracting an upper-layer extracting solution; adding diethyl ether-petroleum ether into the subnatant from which the upper-layer liquid is extracted, separating and extracting an upper-layer extracting solution; evaporating the upper-layer extracting solution until the upper-layer extracting solution is dry to obtain crude PHA, and collecting and filtering obtained subnatant to obtain a solid substance; drying the crude PHA and the solid substance to obtain dried crude PHA and a dried solid substance, and mixing the dried crude PHA and the dried solid substance to obtain a mixture; adding gamma-glycidyl ether oxypropyl trimethoxy silane into the mixture, oscillating, and carrying out cross-linking reaction by adopting a melt blending method to obtain a finished product. The PHA in the sludge pyrohydrolysate is extracted by adopting a new extraction method, so that the performance of the prepared bioplastic is improved, and the sludge resource utilization degree is increased.

Description

Technical Field

[0001] This invention relates to the field of bioplastics, and more particularly to a method for extracting and preparing modified bioplastics from pyrolysis solutions. Background Technology

[0002] In today's society, with continuous economic development, polymer materials have brought great convenience to people's lives, and their applications are becoming increasingly widespread, with usage increasing year by year. However, discarded polymer materials have caused significant environmental pollution problems, with "white pollution" being the most prominent. Landfilling is currently the most common method for disposing of waste plastics. Numerous studies have shown that ordinary plastics buried in soil will not degrade for decades or even centuries, causing serious pollution to soil and groundwater. Furthermore, the remediation of this pollution is extremely costly and yields minimal results. Therefore, it is necessary to develop biodegradable polymer materials, which can not only reduce the environmental pollution caused by waste plastics but also save a significant amount of human, material, and financial resources. Polyhydroxyalkanoates (PHAs) are a biodegradable natural polymer material with similar physicochemical properties to synthetic plastics, as well as advantages such as good biocompatibility and degradability.

[0003] The invention patent with publication number CN102505025B discloses a method for synthesizing polyhydroxy fatty acid esters using residual sludge fermentation broth as a substrate. This method uses activated sludge anaerobic fermentation broth as a substrate to supply microorganisms for PHA synthesis, thereby increasing the yield of polyhydroxy fatty acid esters, but does not improve the extraction method of PHA from microorganisms.

[0004] The invention patent with publication number CN111349218B discloses a method for separating polyhydroxy fatty acid esters using a plate and frame filter press. However, directly using physical methods to separate polyhydroxy fatty acid esters has problems such as many impurities and difficulty in separation and purification.

[0005] Due to its low mechanical strength, poor thermal stability, difficulty in crystallization, and narrow processing window, PHA cannot be widely used. Patent CN107828227A discloses a method for preparing bioplastics by modifying wood flour using a shielding method, which increases the structural strength of the bioplastics. However, this method cannot be applied to polyhydroxyalkanoate-based bioplastics, limiting its application scope.

[0006] Hot hydrolysis of sludge is a common method for sludge reduction and disposal. During the process, large solid organic molecules break down into smaller organic molecules such as volatile fatty acids and esters, which dissolve in the liquid phase. This process also includes a large amount of bioplastic raw materials such as PHA and PHB. The remaining solids contain an increased proportion of inorganic matter, including silicon oxides and some long-chain macromolecules found in wastewater influent, such as guaiacol-sinin-p-hydroxybenzene lignin and polysaccharides. Currently, sanitary landfill is commonly used to dispose of hydrolyzed sludge, but this method suffers from low resource utilization and large land area requirements. Summary of the Invention

[0007] The purpose of this invention is to provide a method for extracting pyrolysis solutions and preparing modified bioplastics.

[0008] The innovation of this invention lies in the new method for extracting PHA from hydrolysate provided by this invention. By adding guaiac alcohol-sinol-p-hydroxybenzene lignin and polymeric polysaccharides that cannot be hydrolyzed after sludge hydrolysis, the mechanical properties and heat distortion temperature of the composite material are improved. Furthermore, by using byproducts from the hot hydrolysis process, resource consumption is reduced.

[0009] To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0010] A method for extracting and preparing modified bioplastics from pyrolysis solutions includes the following steps:

[0011] (1) Take the sludge after filter pressing from the municipal sewage treatment plant, add water and NaOH and stir evenly to obtain stirred sludge. The mass ratio of sludge, water and NaOH is 1000:1000:8~100.

[0012] (2) Add the stirred sludge from step (1) into the hydrothermal reactor, seal it, and heat it to [temperature missing].

[0013] Heat at 100–180°C, stop heating immediately after reaching the temperature, and allow to cool to obtain the reactants.

[0014] (3) Prepare a mixture of diethyl ether and petroleum ether, with a volume ratio of diethyl ether to petroleum ether of 0.5 to 2:1;

[0015] (4) Add an equal volume of diethyl ether-petroleum ether mixture to the reactants in step (2) to obtain a preliminary mixed solution;

[0016] (5) Separate the preliminary mixed solution from step (4) and extract the upper extract;

[0017] (6) Add an equal volume of diethyl ether-petroleum ether to the lower layer after the upper layer has been extracted to obtain an intermediate mixed solution. Separate the intermediate mixed solution and extract the upper extract.

[0018] (7) Repeat step (6) 3 to 5 times;

[0019] (8) Evaporate the upper extract obtained in steps (5)(6)(7) to dryness to obtain crude PHA. Collect and filter the lower liquid obtained in steps (5)(6)(7) to obtain supernatant and solid substance.

[0020] (9) After drying the crude PHA and solid material in step (8) for 24 to 30 hours, dry crude PHA and dry solid material are obtained. The dry crude PHA and dry solid material are mixed to obtain a mixture. The mass ratio of dry crude PHA to dry solid material is 1:30 to 70.

[0021] (10) Add γ-glycidyl etheroxypropyltrimethoxysilane to the mixture from step (9) and shake for 0.5–2 h. Use a melt blending method to dry the crude PHA and the dry solid material.

[0022] A cross-linking reaction occurs, ultimately yielding the final product.

[0023] Furthermore, in steps (5) and (6), a separatory funnel is used for separation, and the bottle is shaken for 1 to 5 minutes after the cap is tightly closed before separation.

[0024] Furthermore, the evaporation in step (8) is rotary evaporation or vacuum evaporation. The temperature of rotary evaporation is 30-40℃ and the rotation speed is 50-90 rpm. The temperature of vacuum evaporation is 30-40℃, the nitrogen flow rate of the nitrogen blower is 300 mL / min, and the temperature is 30-40℃.

[0025] Furthermore, a 0.45μm aqueous filter membrane is used for filtration in step (8).

[0026] Furthermore, the drying in step (9) is vacuum drying.

[0027] The beneficial effects of this invention are:

[0028] 1. This invention uses a novel raw material for PHA production—sludge pyrolysis liquid—and employs a new extraction method to extract PHA from the sludge hot hydrolysis liquid. At the same time, it utilizes the residual inorganic matter that is difficult to hydrolyze to modify PHA, thereby improving the performance of the prepared bioplastics and increasing the resource utilization rate of sludge. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0030] Example 1: A method for extracting and preparing modified bioplastics from pyrolysis solutions, comprising the following steps:

[0031] (1) Take the sludge after filter pressing from the municipal sewage treatment plant, add water and NaOH and stir evenly to obtain stirred sludge. The mass ratio of sludge, water and NaOH is 1000:1000:8.

[0032] (2) Add the stirred sludge from step (1) into the hydrothermal reactor, seal it, and heat it to 100°C. Once the temperature is reached, stop heating immediately and let it cool to obtain the reactants.

[0033] (3) Prepare a mixture of diethyl ether and petroleum ether with a volume ratio of 0.5:1.

[0034] (4) Add an equal volume of diethyl ether-petroleum ether mixture to the reactants in step (2) to obtain a preliminary mixed solution;

[0035] (5) Separate the preliminary mixed solution in step (4) and extract the upper extract. Use a separatory funnel for separation. After sealing the bottle cap, shake for 1 minute and then separate.

[0036] (6) Add an equal volume of diethyl ether-petroleum ether to the lower layer after the upper layer has been extracted to obtain an intermediate mixed solution. Separate the intermediate mixed solution and extract the upper extract. Use a separatory funnel for separation. After sealing the bottle cap tightly, shake for 1 minute before separation.

[0037] (7) Repeat step (6) 3 times;

[0038] (8) Evaporate the upper extract obtained in steps (5)(6)(7) to dryness to obtain crude PHA. Collect and filter the lower liquid obtained in steps (5)(6)(7) to obtain supernatant and solid matter. Use a 0.45μm aqueous filter membrane for filtration. Evaporation is rotary evaporation. The temperature of rotary evaporation is 30℃ and the rotation speed is 50rpm.

[0039] (9) After drying the crude PHA and solid material in step (8) for 24 hours, dry crude PHA and dry solid material are obtained. The drying is vacuum drying. The dry crude PHA and dry solid material are mixed to obtain a mixture. The mass ratio of dry crude PHA and dry solid material is 1:30.

[0040] (10) Add γ-glycidoxypropyltrimethoxysilane to the mixture from step (9) and

[0041] Shake for 0.5 hours, then use a melt blending method to react the dried crude PHA and the dried solid material.

[0042] A cross-linking reaction occurs, ultimately yielding the final product.

[0043] Example 2: A method for extracting and preparing modified bioplastics from pyrolysis solutions, comprising the following steps:

[0044] (1) Take the sludge from the municipal wastewater treatment plant after filter pressing, add water and NaOH, and stir evenly to obtain...

[0045] Stir the sludge, with the mass ratio of sludge, water and NaOH being 1000:1000:50;

[0046] (2) Add the stirred sludge from step (1) into the hydrothermal reactor, seal it, and heat it to 140°C. Once the temperature is reached, stop heating immediately and let it cool to obtain the reactants.

[0047] (3) Prepare a mixture of diethyl ether and petroleum ether with a volume ratio of 1:1.

[0048] (4) Add an equal volume of diethyl ether-petroleum ether mixture to the reactants in step (2) to obtain the initial product.

[0049] Step-by-step mixed solution;

[0050] (5) Separate the preliminary mixed solution from step (4) and extract the upper extract. During separation, use...

[0051] Use a separatory funnel, seal the bottle cap tightly, shake for 3 minutes, and then separate.

[0052] (6) Add an equal volume of diethyl ether-petroleum ether to the lower layer after the upper layer has been extracted to obtain the intermediate layer.

[0053] The mixed solution is separated, and the upper extract is extracted. The separation is performed using...

[0054] Separating funnel, after tightly sealing the bottle cap, shake for 3 minutes and then separate;

[0055] (7) Repeat step (6) 4 times;

[0056] (8) Evaporate the upper extract obtained in steps (5), (6), and (7) to dryness to obtain crude PHA. Collect and filter the lower liquid obtained in steps (5), (6), and (7) to obtain supernatant and solid matter. Use a 0.45 μm aqueous filter membrane for filtration. Evaporation is performed by rotary evaporation.

[0057] The evaporation temperature was 35℃ and the rotation speed was 70 rpm;

[0058] (9) After drying the crude PHA and solid material in step (8) for 26 hours, dry crude PHA and dry solid material are obtained. The drying is vacuum drying. The dry crude PHA and dry solid material are mixed to obtain a mixture. The mass ratio of dry crude PHA and dry solid material is 1:50.

[0059] (10) Add γ-glycidoxypropyltrimethoxysilane to the mixture from step (9) and

[0060] Shake for 1 hour, then use a melt blending method to react the dried crude PHA and the dried solid material.

[0061] The cross-linking reaction ultimately yields the final product.

[0062] Example 3: A method for extracting and preparing modified bioplastics from pyrolysis solutions, comprising the following steps:

[0063] (1) Take the sludge from the municipal wastewater treatment plant after filter pressing, add water and NaOH, and stir evenly to obtain...

[0064] Stir the sludge, with the mass ratio of sludge, water and NaOH being 1000:1000:100;

[0065] (2) Add the stirred sludge from step (1) into the hydrothermal reactor, seal it, and heat it to 180°C. Once the temperature is reached, stop heating immediately and let it cool to obtain the reactants.

[0066] (3) Prepare a mixture of diethyl ether and petroleum ether with a volume ratio of 2:1.

[0067] (4) Add an equal volume of diethyl ether-petroleum ether mixture to the reactants in step (2) to obtain the initial product.

[0068] Step-by-step mixed solution;

[0069] (5) Separate the preliminary mixed solution from step (4) and extract the upper extract. During separation, use...

[0070] Use a separatory funnel, seal the bottle tightly, shake for 5 minutes, and then separate.

[0071] (6) Add an equal volume of diethyl ether-petroleum ether to the lower layer after the upper layer has been extracted to obtain the intermediate layer.

[0072] The mixed solution is separated, and the upper extract is extracted. The separation is performed using...

[0073] Separating funnel, after tightly sealing the bottle cap, shake for 5 minutes and then separate;

[0074] (7) Repeat step (6) 5 times;

[0075] (8) Evaporate the upper extract obtained in steps (5)(6)(7) to dryness to obtain crude PHA. Collect and filter the lower liquid obtained in steps (5)(6)(7) to obtain supernatant and solid matter. Use a 0.45μm aqueous filter membrane for filtration. Evaporation is rotary evaporation. The temperature of rotary evaporation is 40℃ and the rotation speed is 90rpm.

[0076] (9) After drying the crude PHA and solid material in step (8) for 30 hours, dry crude PHA and dry solid material are obtained. The drying is vacuum drying. The dry crude PHA and dry solid material are mixed to obtain a mixture. The mass ratio of dry crude PHA and dry solid material is 1:70.

[0077] (10) Add γ-glycidyl oxypropyltrimethoxysilane to the mixture in step (9) and shake for 2 hours. Use melt blending to crosslink the dried crude PHA and the dried solid material to obtain the final product.

[0078] Example 4: Referring to Example 1, a method for extracting and preparing modified bioplastics from pyrolysis solution includes the following steps: evaporation is vacuum evaporation, the vacuum evaporation temperature is 30°C, the nitrogen flow rate of the nitrogen blower is 300 mL / min, and the temperature is 30°C.

[0079] Example 5: Referring to Example 2, a method for extracting and preparing modified bioplastics from pyrolysis solution includes the following steps: evaporation is vacuum evaporation, the vacuum evaporation temperature is 35°C, the nitrogen flow rate of the nitrogen blower is 300 mL / min, and the temperature is 35°C.

[0080] Example 6: Referring to Example 3, a method for extracting and preparing modified bioplastics from pyrolysis solution includes the following steps: evaporation is vacuum evaporation, the vacuum evaporation temperature is 40°C, the nitrogen flow rate of the nitrogen blower is 300 mL / min, and the temperature is 40°C.

[0081] Comparative Example 1: Referring to Example 1, in step (9), when mixing the dried crude PHA and the dried solid material to obtain a mixture, fly ash and cellulose (bamboo powder) were used to replace the dried solid material during mixing.

[0082] Comparative Example 2: Referring to Example 1, in step (9), when mixing the dried crude PHA and the dried solid material to obtain a mixture, cellulose (bamboo powder) was used to replace the dried solid material during mixing.

[0083] The finished products from Examples 1-3 and Comparative Examples 1 and 2 were injection molded into bioplastics to form specimens, and the mechanical properties of the formed bioplastics were measured.

[0084] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Fracture strength / MPa 170.6 325.7 223.6 30.2 50.1

[0085] The described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for extracting and preparing modified bioplastics from pyrolysis solutions, characterized in that, Includes the following steps: (1) Take the sludge after filter pressing from the municipal sewage treatment plant, add water and NaOH and stir evenly to obtain stirred sludge. The mass ratio of sludge, water and NaOH is 1000:1000:8~100. (2) Add the stirred sludge from step (1) into the hydrothermal reactor, seal it, and heat it to [temperature missing]. Heat at 100–180°C, stop heating immediately after reaching the temperature, and allow to cool to obtain the reactants. (3) Prepare a mixture of diethyl ether and petroleum ether, with a volume ratio of diethyl ether to petroleum ether of 0.5 to 2:1; (4) Add an equal volume of diethyl ether-petroleum ether mixture to the reactants in step (2) to obtain a preliminary mixed solution; (5) Separate the preliminary mixed solution from step (4) and extract the upper extract; (6) Add an equal volume of diethyl ether-petroleum ether to the lower layer after the upper layer has been extracted to obtain an intermediate mixed solution. Separate the intermediate mixed solution and extract the upper extract. (7) Repeat step (6) 3 to 5 times; (8) Evaporate the upper extract obtained in steps (5)(6)(7) to dryness to obtain crude PHA. Collect and filter the lower liquid obtained in steps (5)(6)(7) to obtain supernatant and solid substance. (9) After drying the crude PHA and solid material in step (8) for 24 to 30 hours, dry crude PHA and dry solid material are obtained. The dry crude PHA and dry solid material are mixed to obtain a mixture. The mass ratio of dry crude PHA to dry solid material is 1:30 to 70. (10) Add γ-glycidyl oxypropyltrimethoxysilane to the mixture in step (9) and shake for 0.5 to 2 hours. Use melt blending to crosslink the dried crude PHA and the dried solid material to obtain the final product.

2. The method for extracting and preparing modified bioplastics from pyrolysis solution according to claim 1, characterized in that, In steps (5) and (6), a separatory funnel is used for separation. After the bottle cap is tightly sealed, the mixture is shaken for 1 to 5 minutes before separation.

3. The method for extracting pyrolysis solution and preparing modified bioplastics according to claim 1, characterized in that, The evaporation in step (8) is either rotary evaporation or vacuum evaporation. The temperature of rotary evaporation is 30-40℃ and the rotation speed is 50-90 rpm. The temperature of vacuum evaporation is 30-40℃, the nitrogen flow rate of the nitrogen blower is 300 mL / min, and the temperature is 30-40℃.

4. The method for extracting and preparing modified bioplastics from pyrolysis solution according to claim 1, characterized in that, In step (8), a 0.45μm aqueous filter membrane is used for filtration.

5. The method for extracting and preparing modified bioplastics from pyrolysis solution according to claim 1, characterized in that, The drying in step (9) is vacuum drying.