An environmental oil removal treatment agent and a method for preparing the same

Abstract

The present application relates to water pollution treatment technology, especially to an environmental oil removal treatment agent and a preparation method thereof; the preparation method comprises the following steps: modifying chitosan to be lipophilic; co-modifying the lipophilic chitosan with long-chain alkyl to obtain lipophilic chitosan; adding a photoinitiator and carbon powder to the lipophilic chitosan in a weight ratio of 1:0.05-0.1:1, and stirring uniformly to obtain the environmental oil removal treatment agent; modifying the lipophilic chitosan to obtain lipophilic chitosan, dissolving the lipophilic chitosan in an oil-water mixture, and then using light of a specific spectrum to promote the lipophilic chitosan to crosslink in the oil-water mixture and capture oil droplets, so that a hydrophobic gel-like flocculate is finally formed and water is squeezed out, and the oil is convenient to filter or precipitate.

Description

Technical Field

[0001] This invention relates to water pollution control technology, and in particular to an environmental oil removal agent and its preparation method. Background Technology

[0002] Organic wastewater has a significant impact on the human living environment, and various industries are seeking an environmentally friendly method to effectively treat it. For example, Chinese patent CN108569754A discloses an environmentally friendly wastewater treatment agent and its application method, comprising 0.005–0.3% polysaccharide-metal ion catalyst, 0.1–0.6% hydrogen peroxide, and the remainder being an aqueous solution with a pH of 1–14. The polysaccharide-metal ion catalyst is composed of polysaccharides and metal ion salts. This treatment agent is based on natural polysaccharides, which are widely available, simple to synthesize, and inexpensive, and exhibits good treatment effects under both acidic and alkaline conditions.

[0003] Hydrogen peroxide is a conventional oxidant used to generate hydroxyl radicals, thereby treating organic matter in wastewater. Polysaccharide-metal ion catalysts, on the other hand, utilize polysaccharides to complex metal ions, allowing the metal ions to remain stable within the complex without losing their catalytic activity.

[0004] The existing technology has shortcomings: it requires the addition of metal salts, which may cause secondary pollution. In particular, the aforementioned technical solutions describe the use of chromium salts, which can easily lead to heavy metal pollution. Summary of the Invention

[0005] To address the shortcomings of existing technologies, one objective of this invention is to provide a method for preparing an environmental degreasing agent; another objective is to provide the environmental degreasing agent; and a third objective is to provide a method for using the environmental degreasing agent.

[0006] One of the objectives of this invention is achieved through the following technical solution:

[0007] A method for preparing an environmental degreasing agent includes the following steps:

[0008] Step 1: Lipophilic modification of chitosan;

[0009] Step 2: Long-chain alkyl co-modification yields lipophilic chitosan;

[0010] Step 3: Add the lipophilic chitosan to the photoinitiator and carbon powder at a weight ratio of 1:0.05-0.1:1, and stir evenly to obtain the environmental degreasing agent.

[0011] Specifically, the chitosan lipophilic modification method is as follows:

[0012] 1) Dissolve 1g of chitosan in 100mL of 1% acetic acid solution (pH approximately 5.0) and stir until transparent;

[0013] 2) Add 0.5 molar amounts of methacrylic anhydride (MA) based on the amino content of chitosan, and react at 25°C for 24 hours to obtain the reaction solution;

[0014] 3) Dialyze the reaction solution against deionized water for 3 days (put the reaction solution into a dialysis bag and seal it, then immerse the dialysis bag in a large amount of deionized water, using the concentration difference to drive small molecule impurities to diffuse from the inside of the dialysis bag into the water), and freeze-dry the reaction solution to obtain CSMA white solid.

[0015] Furthermore, the dialysis bag used in the dialysis has a molecular weight cutoff (MWCO) of 8 kDa, which means the molecular weight cutoff is 8 kDa.

[0016] Specifically, the long-chain alkyl co-modification method:

[0017] 1) Dissolve CSMA white solid in 20 mL of anhydrous dimethyl sulfoxide (DMSO), and add 1.5 molar amounts of triethylamine (TEA) based on CSMA.

[0018] 2) Add 0.25 molar amounts of stearoyl chloride based on the amino content of chitosan, and react at 60°C for 12 hours under a nitrogen atmosphere;

[0019] 3) Pour the reaction solution into cold ethanol to precipitate, centrifuge to collect the solid, wash three times to remove unreacted reagents, freeze-dry into powder to obtain lipophilic chitosan.

[0020] Specifically, the carbon powder is replaced with a metal salt, namely copper sulfate pentahydrate (CuSO4·5H2O) powder. It is known that copper sulfate pentahydrate is relatively stable under normal conditions, which is beneficial for storage. This embodiment is a high-catalytic activity case.

[0021] Specifically, the photoinitiator is Irgacure 2959.

[0022] Specifically, the stirring method is to stir at 30-60 r / min in an environment of 2-5℃. This is to avoid the photoinitiator from being deactivated due to high temperature.

[0023] The second objective of this invention is achieved through the following technical solution:

[0024] An environmental degreasing agent prepared using the above method.

[0025] The third objective of this invention is achieved through the following technical solution:

[0026] The method of using the environmental oil removal agent (suitable for treating oily wastewater) includes the following steps:

[0027] Step 1: Mix the environmental degreasing agent and citric acid at a weight ratio of 9:1 to obtain a mixture;

[0028] Step 2: Mix the mixture with the wastewater to be treated at a weight ratio of 2:1000 and then disperse it to form micron-sized oil droplets (for example, disperse it for 2 minutes at 10000 r / min using an emulsifier) ​​to obtain mixed wastewater;

[0029] Step 3: Introduce the mixed wastewater into a 0.3cm deep tank and irradiate it with 365nm UV light. UV irradiation parameters: 50mW / cm 2 3-5 minutes;

[0030] Step four: Filter or allow natural sedimentation to separate the flocculent material from the water.

[0031] Another method of using the environmental oil removal agent (suitable for treating wastewater containing algae) includes the following steps:

[0032] An environmental degreasing agent and citric acid were mixed at a weight ratio of 9:1 to obtain a mixture. This mixture was then mixed with deionized water at a weight ratio of 1:100. The mixture was introduced into a water tank with a depth of 0.3 cm and irradiated with 365 nm UV light. The UV irradiation parameters were 50 mW / cm². 2 After 3-5 minutes, flocculent material is obtained. The flocculent material is then mixed with an equal weight of 3% hydrogen peroxide and added to the algae-polluted water body.

[0033] The beneficial effects of this invention are as follows: A lipophilic chitosan is obtained through modification. This lipophilic chitosan is dissolved in an oil-water mixture, and then irradiation with a specific spectrum of light promotes cross-linking of the chitosan in the oil-water mixture, capturing oil droplets and ultimately forming a hydrophobic gel-like flocculant. Water is then squeezed out, facilitating filtration or oil precipitation. Furthermore, this invention also confirms that the flocculant, when mixed with hydrogen peroxide, also possesses the ability to treat algae pollution. An unexpected discovery was made: this catalytic method still has a certain inhibitory effect on algae even after hydrogen peroxide is depleted. Detailed Implementation

[0034] The following is a further explanation with reference to specific implementation methods:

[0035] Example 1

[0036] Preparation of environmental degreasing agents:

[0037] Step 1: Lipophilic modification of chitosan;

[0038] 1) Dissolve 1g of chitosan in 100mL of 1% acetic acid solution and stir until transparent;

[0039] 2) Add 0.5 molar amounts of methacrylic anhydride based on the amino content of chitosan, and react at 25°C for 24 hours to obtain the reaction solution;

[0040] 3) Dialyze the reaction solution (MWCO = 8 kDa) against deionized water for 3 days, and freeze-dry the reaction solution to obtain CSMA white solid.

[0041] Step 2: Long-chain alkyl co-modification yields lipophilic chitosan;

[0042] 1) Dissolve CSMA white solid in 20 mL of anhydrous dimethyl sulfoxide, and add 1.5 molar amounts of triethylamine based on CSMA.

[0043] 2) Add 0.25 molar amounts of stearoyl chloride based on the amino content of chitosan, and react at 60°C for 12 hours under a nitrogen atmosphere;

[0044] 3) Pour the reaction solution into cold ethanol to precipitate, centrifuge to collect the solid, wash three times to remove unreacted reagents, freeze-dry to obtain lipophilic chitosan;

[0045] Step 3: Add lipophilic chitosan to Irgacure 2959 and charcoal powder (the charcoal powder is obtained by carbonizing and crushing rice husks and passing them through a 100-mesh sieve, the same below) at a weight ratio of 1:0.05:1, and stir evenly at 30 r / min in an environment of 2℃ to obtain an environmental degreasing agent.

[0046] Example 2

[0047] Preparation of environmental degreasing agents:

[0048] Step 1: Lipophilic modification of chitosan;

[0049] 1) Dissolve 1g of chitosan in 100mL of 1% acetic acid solution and stir until transparent;

[0050] 2) Add 0.5 molar amounts of methacrylic anhydride based on the amino content of chitosan, and react at 25°C for 24 hours to obtain the reaction solution;

[0051] 3) Dialyze the reaction solution (MWCO = 8 kDa) against deionized water for 3 days, and freeze-dry the reaction solution to obtain CSMA white solid.

[0052] Step 2: Long-chain alkyl co-modification yields lipophilic chitosan;

[0053] 1) Dissolve CSMA white solid in 20 mL of anhydrous dimethyl sulfoxide, and add 1.5 molar amounts of triethylamine based on CSMA.

[0054] 2) Add 0.25 molar amounts of stearoyl chloride based on the amino content of chitosan, and react at 60°C for 12 hours under a nitrogen atmosphere;

[0055] 3) Pour the reaction solution into cold ethanol to precipitate, centrifuge to collect the solid, wash three times to remove unreacted reagents, freeze-dry to obtain lipophilic chitosan;

[0056] Step 3: Add lipophilic chitosan to Irgacure 2959 and charcoal powder at a weight ratio of 1:0.08:1, and stir evenly at 60 r / min in an environment of 5℃ to obtain an environmental degreasing agent.

[0057] Example 3

[0058] Preparation of environmental degreasing agents:

[0059] Step 1: Lipophilic modification of chitosan;

[0060] 1) Dissolve 1g of chitosan in 100mL of 1% acetic acid solution and stir until transparent;

[0061] 2) Add 0.5 molar amounts of methacrylic anhydride based on the amino content of chitosan, and react at 25°C for 24 hours to obtain the reaction solution;

[0062] 3) Dialyze the reaction solution (MWCO = 8 kDa) against deionized water for 3 days, and freeze-dry the reaction solution to obtain CSMA white solid.

[0063] Step 2: Long-chain alkyl co-modification yields lipophilic chitosan;

[0064] 1) Dissolve CSMA white solid in 20 mL of anhydrous dimethyl sulfoxide, and add 1.5 molar amounts of triethylamine based on CSMA.

[0065] 2) Add 0.25 molar amounts of stearoyl chloride based on the amino content of chitosan, and react at 60°C for 12 hours under a nitrogen atmosphere;

[0066] 3) Pour the reaction solution into cold ethanol to precipitate, centrifuge to collect the solid, wash three times to remove unreacted reagents, freeze-dry to obtain lipophilic chitosan;

[0067] Step 3: Add lipophilic chitosan to Irgacure 2959 and charcoal powder at a weight ratio of 1:0.07:1, and stir evenly at 40 r / min in an environment of 3℃ to obtain an environmental degreasing agent.

[0068] Example 4

[0069] In step three, lipophilic chitosan is added to Irgacure 2959 and copper sulfate pentahydrate (CuSO4·5H2O) powder at a weight ratio of 1:0.07:1, and stirred evenly at 40 r / min in an environment of 3°C to obtain an environmental degreasing agent. The remaining steps are the same as in Example 3.

[0070] Example 5

[0071] Step 1: Mix the environmental degreasing agent obtained in Example 3 with citric acid at a weight ratio of 9:1 to obtain a mixture;

[0072] Step 2: Mix the mixture with the wastewater to be treated (soybean oil suspension, oil content 1000 mg / L, simulating the oil content of wastewater from the catering industry) at a weight ratio of 2:1000 and then disperse it to form micron-sized oil droplets (dispersed for 2 minutes at 10000 r / min using an emulsifier) ​​to obtain mixed wastewater;

[0073] Step 3: Introduce the mixed wastewater into a 0.3cm deep tank and irradiate it with 365nm UV light. UV irradiation parameters: 50mW / cm 2 3 minutes;

[0074] Step four involves filtering and separating the flocculants and water, and determining the oil content in the water (using the method HJ 637-2018) to be 114 mg / L. Although the technical effect is insufficient to reduce the oil content of kitchen wastewater to a level suitable for safe discharge, the oil content has been significantly reduced and is close to the first-class standard (100 mg / L), thus this technical solution has practical significance.

[0075] Example 6

[0076] 2 mg of the environmental degreasing agent obtained in Example 3 was mixed with citric acid at a weight ratio of 9:1 to obtain a mixture. The mixture was then mixed with deionized water at a weight ratio of 1:100, introduced into a water tank with a depth of 0.3 cm, and irradiated with 365 nm UV light. The UV irradiation parameters were 50 mW / cm². 2 After 3 minutes, flocculent material was obtained.

[0077] The flocculant (used directly after filtration, without drying) was mixed with an equal weight of 3% hydrogen peroxide. 50 mL of this mixture was then added to 450 mL of a green algae culture medium with a chlorophyll α concentration of 30 μg / L (simulating eutrophic green algae pollution in water; the culture medium was "Aquatic No. 4" medium, and the green algae were cultured until the chlorophyll α concentration reached 30 μg / L). After 12 hours, the chlorophyll α concentration in the green algae culture medium was measured using the method specified in HJ 897-2017 (the same applies below), and the concentration was 9 μg / L. This demonstrates that the present invention possesses strong catalytic decomposition capabilities even without the use of metal salt catalysts. Furthermore, it can be inferred that the environmental oil removal agent of the present invention can be used in situations involving mixed oil and algae pollution. First, the environmental oil removal agent captures the oil and generates flocculants, which are then used to catalyze the decomposition of algae by hydrogen peroxide.

[0078] Example 7

[0079] The environmental degreasing agent is from Example 4, and the remaining steps are as described in Example 6.

[0080] After 6 hours, the chlorophyll α concentration in the green algae culture medium was measured to be 7 μg / L. The experimental data with added metal salt showed no substantial difference in efficacy against that of Comparative Example 6 (without added metal salt) in decomposing algae; both could treat eutrophic algae-infested wastewater to a safe range (<10 μg / L), further verifying that the present invention achieves near-existing effects even without added metal salt. However, it should be noted that the decomposition time without metal salt was 12 hours, while the decomposition efficiency of Example 7, containing metal salt, was significantly improved.

[0081] Comparative Example 1

[0082] The flocculent obtained in Example 6 was mixed with an equal weight of 3% hydrogen peroxide, and 50 mL was allowed to stand for 1 hour. Then, 5 g of cysteine ​​was added and allowed to stand for another 1 hour. Finally, 450 mL of green algae culture medium was added. The chlorophyll α concentration of the green algae culture medium was 10 μg / L before the experiment. After incubation at 30℃ for 24 hours, the chlorophyll α concentration was measured. The concentration was 12 μg / L.

[0083] Comparative Example 2

[0084] Add 5g of cysteine ​​to 3% hydrogen peroxide (equal in weight to the flocculant obtained in Example 6) and let stand for 1 hour. Then, add the flocculant obtained in Example 5 and 450mL of green algae culture medium. The chlorophyll α concentration of the green algae culture medium was 10μg / L before the experiment. After incubation at 30℃ for 24 hours, the chlorophyll α concentration was measured. The concentration was 20μg / L.

[0085] Cysteine ​​is known to react rapidly with hydrogen peroxide, thus consuming the hydrogen peroxide. Furthermore, cysteine ​​is not toxic to green algae. However, in Comparative Example 1, even after the hydrogen peroxide was consumed, the algal proliferation rate was still significantly lower than in Comparative Example 2. Since the components and proportions used in Comparative Examples 1 and 2 were the same, only the order of addition differed, it can be inferred that the flocculant reacted with hydrogen peroxide to produce a product that inhibits algal proliferation.

[0086] Explanation of the source of raw materials in the examples and comparative examples:

[0087] The charcoal powder was homemade, while the other reagents and raw materials were purchased through conventional commercial channels. Among them, the degree of deacetylation of chitosan was ≥90%, and the molecular weight was 50kDa.

[0088] The embodiments and descriptions above are merely illustrative of the principles and preferred embodiments of the present invention. Various changes and modifications may be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for preparing an environmental degreasing agent, characterized in that, Includes the following steps: Step 1: Lipophilic modification of chitosan; Step 2: Long-chain alkyl co-modification yields lipophilic chitosan; Step 3: Add the lipophilic chitosan to the photoinitiator and carbon powder at a weight ratio of 1:0.05-0.1:1, and stir evenly to obtain the environmental degreasing agent; The chitosan lipophilic modification method: 1) Dissolve 1g of chitosan in 100mL of 1% acetic acid solution and stir until transparent; 2) Add 0.5 molar amounts of methacrylic anhydride based on the amino content of chitosan, and react at 25°C for 24 hours to obtain the reaction solution; 3) The reaction solution was placed into a dialysis bag and sealed. The dialysis bag was then immersed in a large amount of deionized water for 3 days. Small molecule impurities were driven to diffuse from the inside of the dialysis bag into the water by the concentration difference. The reaction solution was then removed and freeze-dried to obtain CSMA white solid. The dialysis bag used in the dialysis had a MWCO of 8 kDa. The long-chain alkyl co-modification method: 1) Dissolve CSMA white solid in 20 mL of anhydrous dimethyl sulfoxide, and add 1.5 molar amounts of triethylamine based on CSMA. 2) Add 0.25 molar amounts of stearoyl chloride based on the amino content of chitosan, and react at 60°C for 12 hours under a nitrogen atmosphere; 3) Pour the reaction solution into cold ethanol to precipitate, centrifuge to collect the solid, wash three times to remove unreacted reagents, freeze-dry into powder to obtain lipophilic chitosan.

2. The method for preparing the environmental degreasing agent according to claim 1, characterized in that, The carbon powder is replaced with a metal salt, namely copper sulfate pentahydrate powder.

3. The method for preparing the environmental degreasing agent according to claim 1, characterized in that, The photoinitiator is Irgacure 2959.

4. The method for preparing the environmental degreasing agent according to claim 1, characterized in that, The stirring method is stirring at 30-60 r / min in an environment of 2-5℃.

5. An environmental degreasing agent obtained by the preparation method of the environmental degreasing agent as described in claim 1.

6. A method for treating oily wastewater, characterized in that, Includes the following steps: Step 1: Mix the environmental degreasing agent as described in claim 5 with citric acid at a weight ratio of 9:1 to obtain a mixture; Step 2: Mix the mixture with the wastewater to be treated at a weight ratio of 2:1000 and then disperse the mixture to form micron-sized oil droplets, thus obtaining mixed wastewater; Step 3: Introduce the mixed wastewater into a water tank with a depth of 0.3 cm and irradiate it with 365 nm UV light. UV irradiation parameters: 50 mW / cm², 3-5 min. Step four: Filter or allow natural sedimentation to separate the flocculent material from the water.

7. A method for treating wastewater containing aquatic algae, characterized in that, Includes the following steps: The environmental oil removal agent as described in claim 5 is mixed with citric acid at a weight ratio of 9:1 to obtain a mixture. The mixture is then mixed with deionized water at a weight ratio of 1:

100. The mixture is introduced into a water tank with a depth of 0.3 cm and irradiated with 365 nm UV light. The UV irradiation parameters are 50 mW / cm² for 3-5 min to obtain flocculants. The flocculants are then mixed with an equal weight of 3% hydrogen peroxide and added to algae-polluted water bodies.