Method for reducing dibutyl phthalate

Abstract

The present application relates to the management field of phthalate esters, and in particular to a method for reducing dibutyl phthalate. The method uses a flat-plate to flat-plate electrode low-temperature plasma excitation source based on dielectric barrier discharge technology to generate low-temperature plasma to reduce dibutyl phthalate. The reduction rate of dibutyl phthalate in the method can reach about 60% or more, and the degradation effect is good, and the cytotoxicity is smaller.

Description

Technical Field

[0001] This invention relates to the field of phthalate ester remediation, and more specifically, to a method for reducing dibutyl phthalate. Background Technology

[0002] Phthalate esters (PAEs), commonly known as plasticizers, are widely used in the production and processing of plastic products to improve the flexibility and durability of plastics. PAEs account for 70% of the global plasticizer market, among which dibutyl phthalate (DBP) is one of the most widely used PAEs.

[0003] PAEs have good compatibility with plastics, but they do not form covalent bonds with the plastic matrix; instead, they are linked by hydrogen bonds or van der Waals forces. Therefore, when using plastic products, PAEs are gradually released into the environment, directly or indirectly endangering the health of organisms. Currently, PAEs have become one of the most prevalent organic pollutants globally. PAEs entering water bodies, soil, and other environmental systems, due to their persistence, high stability, bioactivity, slow biodegradability, and bioaccumulation, can accumulate in microorganisms, plants, animals, and humans through the bioaccumulation and amplification effect of the food chain, thus posing potential harm to human health and the ecological environment. Due to their widespread application, PAE pollutants have been detected in many environments, with concentrations in surface water reaching as high as 500 mg·L⁻¹.

[0004] Studies have shown that DBP can interfere with the endocrine system of humans and animals and disrupt reproductive capacity even at low concentrations; at high doses, it also has carcinogenic, teratogenic, and mutagenic effects. Therefore, six PAEs, including DBP, have been listed as priority pollutants by environmental protection organizations in many countries.

[0005] To date, there is a lack of efficient and safe methods for the effective reduction of DBP, both internationally and domestically. Existing methods for reducing and controlling PAEs mainly include abiotic and biological degradation pathways. Abiotic pathways include natural degradation through hydrolysis and photolysis, as well as accelerated degradation or adsorption and sedimentation through physical or chemical methods. Adding exogenous substances to accelerate degradation can address the slow nature of natural degradation. However, these methods may suffer from drawbacks such as slow processes, insufficient degradation, low efficiency, susceptibility to secondary pollution, and limitations on large-scale application. Therefore, research on efficient, safe, and green DBP reduction technologies is particularly important. Summary of the Invention

[0006] The purpose of this invention is to select low-temperature plasma treatment as the core technology, utilize high-pressure gas discharge to generate low-temperature plasma, and conduct experimental research on the elimination of fungal toxins, degrading the concentration of dibutyl phthalate (DBP) and reducing the toxic effects of DBP. This provides a new pathway and scientific basis for constructing efficient, safe, and green persistent pollutant reduction technologies.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0008] This invention relates to a method for reducing dibutyl phthalate, which utilizes a low-temperature plasma excitation source based on dielectric barrier discharge technology to generate low-temperature plasma to reduce dibutyl phthalate.

[0009] Optionally, in the dibutyl phthalate reduction method described above, the effective electrode area during discharge is 18 cm². 2 ~22cm 2 .

[0010] Optionally, in the dibutyl phthalate reduction method described above, the voltage amplitude of the power supply is 3kV to 8kV and the frequency is 10kHz to 50kHz during the reduction process.

[0011] Optionally, in the dibutyl phthalate reduction method described above, a glass carrier is placed on the lower electrode as a blocking medium, and the thickness of the glass carrier is 1.5 mm to 2.5 mm.

[0012] Optionally, in the dibutyl phthalate reduction method described above, the dibutyl phthalate sample is placed inside the glass carrier for reduction, and plasma is generated between the upper electrode and the sample, with an air gap of 1 mm to 3 mm.

[0013] Optionally, in the dibutyl phthalate reduction method described above, the atmosphere for generating the low-temperature plasma is any one or more of air, oxygen-containing gas, nitrogen, and rare gases.

[0014] Optionally, in the dibutyl phthalate reduction method described above, the reduction time is ≥3 min.

[0015] Optionally, in the dibutyl phthalate reduction method described above, the power supply output used for the dielectric barrier discharge is a sinusoidal voltage.

[0016] Optionally, in the dibutyl phthalate reduction method described above, the upper and lower electrodes are circular aluminum plate electrodes.

[0017] According to another aspect of the invention, the invention also relates to the application of the method described above in reducing plastic gaskets and hoses in food, food packaging materials, toys, machinery, medical blood bags and tubing, and dibutyl phthalate in soil.

[0018] Compared with existing technologies, the method provided by this invention utilizes a combination of components generated during the low-temperature plasma generation process, including ultraviolet light, high-energy charged particles, and active substances (molecules, excited-state atoms, metastable atoms, and free radicals), which can comprehensively act on DBP to reduce its toxicity. Compared with traditional detoxification technologies, it has many advantages such as better effectiveness, no need for high temperatures, environmental friendliness, high operational efficiency, no introduction of other pollutants, ease of operation, high safety, and no residue.

[0019] This invention selects low-temperature plasma treatment as the core technology, utilizing high-pressure gas discharge to generate low-temperature plasma for experimental research on DBP reduction, degradation of DBP, and reduction of DBP toxicity. This provides a novel pathway and scientific basis for constructing efficient, safe, and green DBP reduction technologies.

[0020] This method can reduce DBP by more than 60%, with good digestion effect and less cytotoxicity. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This invention illustrates the effects of DBP and DBP solution treated with low-temperature plasma on zebrafish embryo toxicity in one embodiment of the invention. Detailed Implementation

[0023] Reference will now be made to detailed embodiments of the present invention, one or more of which are described below. Each example is provided for explanation and not for limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] This invention relates to a method for reducing dibutyl phthalate, which utilizes a low-temperature plasma excitation source based on dielectric barrier discharge technology to generate low-temperature plasma to reduce dibutyl phthalate.

[0026] The state of matter generally changes from solid to liquid to gas as temperature rises; these three basic states of matter are called the three states of matter. For gaseous matter, if the temperature rises to several thousand degrees Celsius or higher, the molecules intensify their thermal motion, and the violent collisions between them cause the gas molecules to ionize. At this point, the matter becomes a mixture of free electrons and positive ions. This state of matter is called the fourth state of matter, namely the plasma state.

[0027] This invention employs a high-voltage power supply to activate plasma electrodes for micro-discharge. During the low-temperature plasma generation process, various components, including ultraviolet radiation, high-energy charged particles, and active substances (molecules, excited-state atoms, metastable atoms, and free radicals), act collectively on DBP, thereby reducing its toxicity. Compared to traditional detoxification technologies, this invention offers numerous advantages, including high effectiveness, no need for high temperatures, environmental friendliness, high operational efficiency, no introduction of other pollutants, ease of operation, high safety, and no residue.

[0028] In summary, the method provided by this invention has good application prospects.

[0029] In some embodiments, the method is carried out without the addition of an additional catalyst, such as a metal ion catalyst, like Fe or Cu ions.

[0030] In some embodiments, the effective area of ​​the electrode during discharge is 18 cm². 2 ~22cm 2 Alternatively, you can choose 19 cm. 2 20cm 2 21cm 2 20cm 2 .

[0031] In some implementations, the voltage amplitude of the power supply is 3kV to 8kV during the reduction process, but 4kV, 5kV, 6kV or 7kV can also be selected.

[0032] In some implementations, the frequency of the power supply is 10kHz to 50kHz during the reduction process, but 15, 20, 25, 30, 35, 40, or 45kHz can also be selected.

[0033] In some embodiments, a glass carrier is placed on the lower electrode as a barrier medium, and the thickness of the glass carrier is 1.5 mm to 2.5 mm.

[0034] In some embodiments, the glass carrier is a petri dish. The diameter is preferably 70mm to 90mm, and the depth is 1mm to 4mm.

[0035] In some embodiments, the dibutyl phthalate sample is placed inside the glass carrier for attenuation, and plasma is generated between the upper electrode and the sample, with an air gap of 1 mm to 3 mm, or 2 mm.

[0036] The atmosphere used to generate cryogenic plasma can be, for example, an oxygen-containing gas such as O2, H2O, NO2, nitrogen and air, or an inert gas (e.g., helium, neon, argon, krypton, xenon); or a mixture of the above gases. Oxygen-containing gases, particularly O2 and air, are preferred. The pressure can be atmospheric pressure or lower.

[0037] In some implementations, the reduction time is ≥3 min, for example 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, 15 min or more.

[0038] While low-temperature plasma technology does not require harsh operating conditions such as high temperature, high pressure, or the addition of chemical reagents, its generation under high-voltage discharge conditions results in high power consumption, thus making the cost of treating pollutants relatively high. This invention has found that when reducing DBP, if the reduction time is already approximately 3 minutes, further increasing the treatment time does not significantly enhance the reduction effect. Therefore, to improve the energy utilization rate of this invention, reduce energy consumption, and lower treatment costs, in a more preferred embodiment, the reduction time is 2 to 4 minutes, with approximately 3 minutes being the most preferred.

[0039] In some embodiments, the power supply output used for the dielectric barrier discharge is a sinusoidal voltage.

[0040] In some implementations, the upper and lower electrodes are circular aluminum plate electrodes.

[0041] In some embodiments, the electrode diameter is 60mm to 80mm and the electrode edge radius is 8mm to 12mm.

[0042] According to another aspect of the invention, the invention also relates to the application of the method described above in reducing plastic gaskets and hoses in food, food packaging materials, toys, machinery, medical blood bags and tubing, and dibutyl phthalate in soil.

[0043] The embodiments of the present invention will now be described in detail with reference to examples.

[0044] Example

[0045] The present invention provides the following experiments to verify the effect of low-temperature plasma on DBP reduction.

[0046] 1. Method:

[0047] Low-temperature plasma treatment of DBP was performed, and the reduction efficiency of the treated solution was detected by isotope dilution liquid chromatography-tandem mass spectrometry (LMS). The treated solution was then subjected to zebrafish acute embryo experiment (FET) to determine the biological effects.

[0048] 2. Materials and Reagents

[0049] Plasma generating device, DBP samples, standards, petri dishes, centrifuge tubes, sterile water, zebrafish breeding and aquaculture system (Beijing Aisheng Technology Co., Ltd.), etc.

[0050] 3. Experimental steps:

[0051] (1) Solution preparation

[0052] DBP, 1 g / ml, dissolved in ethanol to 0.5 g / ml, and then ultrasonically emulsified with 1% BSA to form a nanoemulsion, diluted with ultrapure water to 0.1 mg / ml, for use in plasma treatment;

[0053] (2) Plasma treatment

[0054] The power supply used in this method is a high-voltage, high-frequency power supply (HFHV20-1 type), which consists of two parts: a control chassis and a high-frequency transformer. The input is a 220V power frequency voltage, and the output is a sinusoidal voltage with an adjustable amplitude of 0–20kV and an adjustable frequency of 10kHz–60kHz. During the experiment, the voltage amplitude was 3–8kV and the frequency was 30kHz. The discharge electrode adopts a plate-type dielectric barrier discharge structure. The upper and lower electrodes are circular aluminum plate electrodes with a diameter of 70mm and an edge radius of 10mm, resulting in an effective electrode area of ​​approximately 19.6cm² during discharge. A glass petri dish with a diameter of 80mm, a thickness of 2mm, and a depth of 2mm is placed on top of the lower electrode as the barrier medium. After DBP preparation, 7ml is injected into the petri dish each time, generating plasma between the upper electrode and the solution surface, with a 2mm air gap. To compare the treatment effect of low-temperature plasma, the treatment time was set to 1 minute (short time), 3 minutes (medium time), and 10 minutes (long time).

[0055] (3) Verification of digestion rate

[0056] Referring to the national standard GB5009.111, the concentration of DBP before and after treatment was determined by liquid chromatography-tandem mass spectrometry to assess the reduction efficiency.

[0057] (4) Validation of biological effects

[0058] Zebrafish (Danio rerio) possess numerous advantages, including small size, in vitro fertilization, and easily observable transparent embryos, making them an ideal model organism for toxicological research. This study investigated the toxic effects of DBP on zebrafish embryos at different developmental stages. Methods: Zebrafish embryos 2 hours post-fertilization (2 hpf) were treated with DBP at concentrations of 0, 0.1, 0.3, 1.0, 3.0, and 10.0 μg / mL. Embryonic development was recorded at time points of 12, 24, 48, 72, and 96 hpf.

[0059] 4. Results

[0060] (1) Digestion rate results

[0061] The results of low-temperature plasma reduction of DBP are shown in Table 1. Low-temperature plasma treatment of DBP for 1 minute resulted in almost no degradation, while treatment for 3 minutes achieved a degradation rate of 61.3%. Treatment for 10 minutes did not show any significant reduction. The results indicate that low-temperature plasma treatment of DBP for three minutes can achieve significant degradation.

[0062] Table 1. DBP attenuation rate after low-temperature plasma treatment

[0063]

[0064] Currently, there are no effective methods for degrading DBP in the environment, either domestically or internationally. Existing research shows that the degradation of such methyl biphenyl esters (PAEs) is mainly achieved through microbial degradation, but there are still no reports on the degradation of DBP by microorganisms. Therefore, this invention is expected to fill the gap in the lack of effective methods for the degradation of DBP in the environment. The following table (Table 2) compares the low-temperature plasma treatment of DBP with the treatment methods in the prior art.

[0065] Table 2. Comparison of low-temperature plasma treatment of DBP with existing treatment methods

[0066]

[0067]

[0068] (2) Results of biological effect verification test FET results showed that DBP significantly inhibited embryonic development, causing abnormal development in zebrafish larvae, including incomplete embryo hatching, egg aggregation at 24 hpf, severe pericardial edema at 72 hpf, and developmental malformations. However, DBP at the same concentration, after plasma treatment, had less impact on the developmental morphology of zebrafish larvae, with only mild pericardial edema observed at high concentrations. (Zebrafish embryonic development status) Figure 1 The toxicity effect value (BMDL) is shown below.

[0069] Note: P-DBP is a DBP solution after low-temperature plasma treatment.

[0070] Using BMDS software and different mathematical models such as Hill, the dose-response relationship between DBP concentration and zebrafish embryonic development indicators (hatching rate) was observed. The toxic effect value of DBP on zebrafish embryonic development (lower limit of baseline dose, BMDL) was calculated. The BMDL of DBP toxicity to zebrafish embryonic development was 0.47930 ug / ml. After plasma treatment, the BMDL was 1.2779 ug / ml, indicating a decrease in toxicity to zebrafish embryos.

[0071] Table 3. Toxicity effects of DBP and DBP solution after low-temperature plasma treatment on zebrafish embryos

[0072]

[0073] References:

[0074] [1] Li Haitao, Huang Suiliang. Study on migration and transformation of phthalates in aquatic environment [J]. Environmental Pollution and Control, 2006, 28(11):853-858.

[0075] [2] Wen Qinliang. Preliminary study on chemical oxidation remediation technology for phthalate contaminated soil [D].

[0076] Nanjing Agricultural University, 2016.

[0077] [3] Daiem MMA, José Rivera-Utrilla, Raúl Ocampo-Pérez, et al. Environmental impact of phthalic acid esters and their removal from waterand sediments by different technologies-A review[J]. Journal of Environmental Management, 2012, 109 (none): 164-178.

[0078] [4]Wu ZY, Zhang XL, Wu XL, et al. Uptake of Di(2-ethylhexyl)Phthalate(DEHP) by the Plant Benincasa hispida and Its Use for Lowering DEHP Content ofIntercropped Vegetables[J]. Journal of Agricultural and Food Chemistry, 2013, 61, 5220-5225.

[0079] [5] Latorre I, Hwang S, Montalvo-Rodriguez R. Isolation and molecular identification of landfill bacteria capable of growing on di-(2-ethylhexyl)phthalate and deteriorating PVC materials [J]. Journal of Environmental Science and Health, Part A, 2012, 47(14): 2254-2262.

[0080] [6] Duan Xingchun, Yi Xiaoyun, Yang Xiaowei, et al. Isolation, identification and degradation characteristics of two dibutyl phthalate degrading bacteria [J]. Journal of Agricultural Environmental Science, 2007, 26(5):1937-1941.

[0081] [7]Wen ZD, Gao DW, Wu W M.Biodebradation and kinetic analysis of phthalates by an Arthrobwcter strain isolated from construtted wetland soil[J].Applied Microbioloby and Biotechnoloby, 2014,98(10):4683-4690.

[0082] [8]Wu

[0083]

[10] Jin Lei, Chen Yu, Yan Zhongyong, et al. Isolation, identification and degradation characteristics of H-2, a highly efficient dibutyl phthalate degrading bacterium [J]. Food Science, 2014, 35(15):202-206.

[0084] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for reducing dibutyl phthalate, characterized in that, Low-temperature plasma was generated using a planar-planar electrode low-temperature plasma excitation source based on dielectric barrier discharge technology to reduce dibutyl phthalate. The dibutyl phthalate, 1 g / mL, was dissolved in ethanol to a concentration of 0.5 g / mL, and then ultrasonically emulsified with 1% BSA to form a nanoemulsion. This nanoemulsion was then diluted with ultrapure water to a concentration of 0.1 mg / mL for plasma treatment. The effective area of ​​the electrode during discharge is 18 cm². 2 ~22cm 2 ; The power supply has a voltage amplitude of 3kV~8kV and a frequency of 30kHz; A glass carrier is placed on top of the lower electrode as a barrier medium, and the thickness of the glass carrier is 1.5mm~2.5mm; The dibutyl phthalate sample is placed in the glass carrier for reduction, and plasma is generated between the upper electrode and the sample, with an air gap of 1 mm to 3 mm. The reduction time is 3 minutes; The power supply output used for the dielectric barrier discharge is a sinusoidal voltage; The upper and lower electrodes are circular aluminum plate electrodes.

2. The method for reducing dibutyl phthalate according to claim 1, characterized in that, The atmosphere that generates low-temperature plasma is any one or more of oxygen-containing gas, nitrogen, and rare gases.

3. The method for reducing dibutyl phthalate according to claim 1, characterized in that, No additional catalyst is added during the implementation of the method.

4. The method for reducing dibutyl phthalate according to claim 1, characterized in that, The voltage amplitude of the power supply is 5kV~6kV.

5. The method for reducing dibutyl phthalate according to claim 1, characterized in that, The glass carrier is a petri dish.

6. The method for reducing dibutyl phthalate according to claim 5, characterized in that, The plate has a diameter of 70mm to 90mm and a depth of 1mm to 4mm.

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