Preparation method of microalgae-SiO2 bio-based nanofluid dust suppressant

Abstract

The invention provides a preparation method of a microalgae-SiO2 bio-based nanofluid dust suppressant, which comprises the following steps: (1) microalgae culture: using a BG-11 culture medium, sterilizing, cooling, inoculating microalgae, carrying out 7-day light / dark cycle culture, and finally filtering and collecting microalgae cells; (2) active component extraction: cleaning microalgae cells, and performing centrifugation, filtration and rotary evaporation treatment through ultrasonic disruption, enzymolysis and a microwave-assisted chloroform-methanol mixed extraction method to obtain microalgae active components; (3) synthesis of SiO2 nanoparticles: mixing the SiO2 precursor with deionized water, adjusting the pH value and diluting, adding microalgae active components, oscillating at a constant temperature, centrifugally separating and purifying the SiO2 nanoparticles; and (4) preparation of the nanofluid dust suppressant: mixing the SiO2 nanoparticles, the microalgae active component and the dispersing agent in water in proportion to prepare the microalgae-SiO2 bio-based nanofluid dust suppressant. The invention is expected to solve the limitation of the traditional dust suppressant, and provides a novel, efficient and environment-friendly dust suppressant preparation method.

Description

Technical Field

[0001] The invention relates to the technical field of dust suppressants, and in particular to a method for preparing a microalgae-SiO2 bio-based nanofluid dust suppressant. Background Art

[0002] In today's society, with the acceleration of industrial production and urbanization, the problem of dust pollution is becoming increasingly serious. Dust not only affects air quality, but also poses a serious threat to human health and the ecological environment. Therefore, dust control has become an important issue in the field of environmental protection and public health. Traditional dust control methods mainly include sprinkling water, covering and spraying chemical dust suppressants, but these methods have certain limitations, such as high cost, low dust removal efficiency, and possible secondary pollution. In addition, existing dust suppressants mostly use chemical synthetic materials, which not only poses a potential burden on the environment, but also may have adverse effects on human health in some cases. Therefore, it is urgent to develop a high-efficiency and environmentally friendly dust suppressant with excellent performance and non-toxicity.

[0003] As a new type of dust suppression technology, nanofluids have received extensive attention in the field of dust control in recent years. Nanofluids are usually formed by nano-sized solid particles dispersed in a liquid medium, and have unique physical and chemical properties, such as high specific surface area, good dispersibility and stability. However, existing nanofluid dust suppressants are mostly focused on the research of a single component, and their wetting, bonding and moisturizing properties are poor, which in turn limits their application effect.

[0004] As a photosynthetic organism, microalgae has the characteristics of fast growth, large biomass, and easy cultivation. It can also produce a variety of biologically active substances through its own metabolism. These active substances, such as polysaccharides and proteins, can increase the adhesion and wettability of dust, making it easier to aggregate and settle, thereby improving the dust suppression effect. Therefore, the microalgae and SiO2 nanofluids are synergistically prepared to obtain microalgae-SiO2 bio-based nanofluid dust suppressants. Not only can the biologically active substances produced by microalgae metabolism make up for the deficiencies of nanofluid dust suppressants in wettability and moisturizing properties, but also the physical and chemical properties of SiO2 nanofluids can be used to adsorb and consolidate dust particles, thereby enhancing the stability of bio-based dust suppressants. This invention is expected to solve the limitations of traditional dust suppressants and provide a new, efficient, and environmentally friendly method for preparing dust suppressants. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is to provide a method for preparing a microalgae-SiO2 bio-based nanofluid dust suppressant in view of the deficiencies in the current technology, so as to solve the technical problems of the existing dust suppressants such as high cost, poor dust suppression effect, unfriendly environment and poor biodegradability. The microalgae-SiO2 bio-based nanofluid dust suppressant of the present invention has the characteristics of good biodegradability, non-toxicity, low cost, excellent dust suppression effect, biocompatibility and safety, and multifunctionality.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] The method for preparing a microalgae-SiO2 bio-based nanofluid dust suppressant is characterized by comprising the following steps:

[0010] (1) Microalgae cultivation

[0011] Prepare BG-11 culture medium according to the growth requirements of the selected microalgae, sterilize the BG-11 culture medium in a high-pressure steam sterilizer at 120°C for 30 minutes and return it to room temperature, inject 100 ml of the culture medium into 250 ml conical flasks, inoculate the selected microalgae, put them into a photobioreactor, and carry out light / dark continuous culture for a certain period of time under certain temperature, light, pH, fixed carbon source and air conditions, and filter and collect the microalgae cells after the culture is completed;

[0012] (2) Extraction of active ingredients from microalgae

[0013] The microalgae collected by filtration in step (1) are pretreated by washing the microalgae cells with deionized water to remove the culture medium residue and impurities; the washed microalgae are crushed by ultrasonic wave to release the active components in the cells, and the crushed microalgae cells are subjected to enzymatic hydrolysis for a certain time at a certain temperature, pH value and enzyme concentration; the enzymatically hydrolyzed microalgae cells are then mixed with a mixed solution of chloroform and methanol, and subjected to microwave extraction, wherein microwave heating can accelerate the solvent penetration and the release of the active components; the mixture after microwave extraction is centrifuged to obtain a supernatant and algae residue, the supernatant is filtered by filter paper to remove the residual solid particles, and the solvent is evaporated from the filtered supernatant by a rotary evaporator until the weight remains unchanged, thereby obtaining the microalgae active components;

[0014] (3) Synthesis of SiO2 nanoparticles

[0015] The SiO2 precursor is mixed with deionized water by ultrasonic oscillation for a certain period of time, diluted to an appropriate concentration, the pH value of the precursor solution is adjusted, and then the diluted SiO2 precursor solution is mixed with the microalgae active ingredient obtained in step (2) in a certain proportion, and the mixture is placed in a constant temperature oscillator and oscillated at a certain temperature and speed for a certain period of time. After the oscillation ends, SiO2 nanoparticles are centrifuged out by a high-speed centrifuge, and purified to obtain SiO2 nanoparticles;

[0016] (4) Synthesis of Nanofluid Dust Suppressants

[0017] The SiO2 nanoparticles synthesized in step (3) are mixed with the microalgae active ingredients and water in proportion, the concentrations of the nanoparticles and the microalgae active ingredients in the nanofluid are adjusted as needed, and the bio-based nanofluid dust suppressant is prepared by ultrasonic dispersion and addition of a suitable dispersant.

[0018] In the above step (1), the microalgae is green algae; the BG-11 culture medium formula includes: 1.5g / L NaNO3, 0.04g / L K2HPO4·3H2O, 0.075g / L MgSO4·7H2O, 0.036g / L CaCl2·2H2O, 0.006g / L citric acid, 0.006g / L ammonium ferric citrate, 0.001g / L ethylenediaminetetraacetic acid, 0.001g / L 2Na-Mg salt, 0.02g / L Na2CO3, 2.86μg / L H3BO4, 1.81μg / L MnCl2·4H2O, 0.222μg / L ZnSO4·7H2O, 0.391μg / L Na2MoO4·2H2O, 0.079μg / L CuSO4·5H2O, 0.0494μg / L Co(NO3)2·6H2O, and the pH of the culture medium was finally adjusted to 7.4.

[0019] In the above step (1), the photobioreactor is a light incubator; the culture temperature is optimized at 20-30°C; the light intensity is optimized at 5000-10000 lux; the pH value is optimized at pH 7.0-8.0; 10-15 ml of CO2 gas is introduced into the fixed carbon source per minute; the air refers to 2.5 liters of air per minute per liter of culture solution; and the light / darkness is 16L / 8D continuous culture.

[0020] In the above step (2), the ultrasonic crushing frequency is 20-40kHz, the power is 100-500W, and the crushing time is 5-15min; the temperature is 40-60°C; the pH is 4.5-6.0; the enzyme is one or both of cellulase and protease; the enzyme concentration is 0.1-1.5wt%, and the enzymatic hydrolysis time is 1-4h, so that the active ingredients in the microalgae cells are fully released.

[0021] In the above step (2), the solution of chloroform and methanol is 1.5-2.5:1 (V:V); the microwave power of the microwave extraction is 200-800W, the frequency is 2.45GHz, and the processing time is 15-30min; the filter paper is Whatman No.1 filter paper; the temperature of the rotary evaporator is set to 50-65°C and the rotation speed is 100rpm.

[0022] In the above step (3), the SiO2 precursor is one of a sodium silicate solution and a potassium silicate solution; the ultrasonic oscillation time is 15 to 30 minutes; the dilution concentration is 15 to 20 wt%, and the dilution helps to control the reaction rate and the uniformity of the product; the pH is adjusted to 7; the microalgae active ingredient obtained in step (2) acts as a reducing agent and stabilizer to prevent the aggregation and growth of nanoparticles; the mixing ratio of the SiO2 precursor solution to the microalgae active ingredient is 5 to 10:1 (v:m).

[0023] In the above step (3), the temperature of the constant temperature oscillator is 35-45°C, the oscillation time is 24-72h, and the oscillation speed is 180rpm; the speed of the high-speed centrifuge is 4000-8000rpm, and the centrifugation time is 10-15min; the purification treatment refers to using a rotary evaporator to evaporate the solvent of the filtered supernatant, and the temperature of the rotary evaporator is set to 50-65°C and the speed is 100rpm to remove unreacted precursors and by-products.

[0024] In the above step (4), the mixing ratio is 0.01-0.15wt%, the ultrasonic dispersion time is 4-6h, the ultrasonic power is 180-200W, the ultrasonic temperature is 30-40°C, and the dispersant is a polycaprolactone polyol-polyethyleneimine block copolymer type dispersant. Ultrasonic treatment can reduce the particle size of the nanoparticles, thereby helping to obtain better dispersibility, which will lead to improved stability and reduced viscosity of the nanofluid.

[0025] The microalgae-SiO2 bio-based nanofluid dust suppressant of the present invention is used by spraying, and the dosage is 0.1-0.5 kg / m2.

[0026] A microalgae-SiO2 bio-based nanofluid dust suppressant obtained by the above-mentioned preparation method.

[0027] (III) Beneficial effects

[0028] The present invention provides a method for preparing a microalgae-SiO2 bio-based nanofluid dust suppressant. It has at least the following beneficial effects:

[0029] (1) Environmental friendliness and biocompatibility. The microalgae-SiO2 bio-based nanofluid dust suppressant of the present invention is based on bio-based materials and has excellent biodegradability, reducing the risk of long-term pollution to the environment. At the same time, the low toxicity characteristics of microalgae and SiO2 ensure its safety to the human body and the ecosystem, and promote the sustainable development of the environment.

[0030] (2) Highly efficient dust suppression performance. The microalgae-SiO2 bio-based nanofluid dust suppressant of the present invention utilizes the special properties of nanomaterials, such as high specific surface area and strong adsorption, to more effectively adsorb and fix tiny particles in the air, thereby significantly improving the dust suppression efficiency. This nanoscale effect allows the dust suppressant to work over a wider range of particle sizes, including ultrafine dust. The synergistic effect of the microalgae active ingredients and the SiO2 nanoparticles improves the wettability and adhesion to the dust particles, making it easier for the dust suppressant to penetrate into the surface of the dust particles, forming a stable coating layer to prevent the dust from flying.

[0031] (3) Broad application prospects and multifunctionality. The microalgae-SiO2 bio-based nanofluid dust suppressant of the present invention is not only suitable for traditional places with serious dust, such as mines and construction sites, but can also be applied to various scenes such as roads, ports, and airports, providing effective solutions for dust control in different fields. At the same time, the additional functions such as antibacterial and anti-inflammatory that the active ingredients of microalgae may bring provide multifunctionality for dust suppressants. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of the preparation process of the present invention. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively by way of examples, and preferred embodiments of the present invention are given below. However, the present invention can be implemented in a variety of different forms and is not limited to the embodiments described herein. Any other implementation schemes obtained by modifying or equivalently replacing the technical scheme of the present invention without creative results are within the protection scope of the present invention.

[0034] The numerical values ​​disclosed in the embodiments of the present invention are approximate values, not definite values. When the error or experimental conditions permit, all values ​​within the error range may be included without being limited to the specific numerical values ​​disclosed in the embodiments of the present invention.

[0035] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0036] The method for synthesizing the microalgae-SiO2 bio-based nanofluid dust suppressant of the present invention is completed by the following steps:

[0037] (1) Microalgae cultivation

[0038] First, prepare BG-11 culture medium, sterilize it in a high-pressure steam sterilizer at 120°C for 30 minutes and then cool it to room temperature, inject 100 ml of the culture medium into 250 ml conical bottles, inoculate the selected microalgae, put them into a light incubator, and carry out 16L / 8D light / dark continuous culture for 7 days at 25°C, 8000 lux, pH 7.0, 10 ml of CO2 per minute, and 2.51 air per minute per liter of culture medium. After the culture is completed, filter and collect the green algae cells;

[0039] (2) Extraction of active ingredients from green algae

[0040] The green algae collected by filtration in step (1) were pretreated, and the green algae cells were washed with deionized water to remove the culture medium residue and impurities; the washed green algae were subjected to ultrasonic wave with a frequency of 30 kHz and a power of 300 W to break the green algae cell wall for 15 minutes to fully release the active ingredients in the green algae cells; the solution pH was adjusted to 5 at 50°C and a concentration of 0.15 wt% of cellulase and protease, and the broken green algae cells were enzymatically hydrolyzed for 2.5 hours; the enzymatically hydrolyzed green algae cells were then added to a mixed solution of chloroform and methanol in a volume ratio of 2:1, and microwave extraction was performed for 30 minutes at a power of 500 W and a frequency of 2.45 GHz. Microwave heating can accelerate solvent penetration and the release of active ingredients; the mixture after microwave extraction was centrifuged at 10,000 rpm for 10 minutes to obtain a supernatant and algae residue, and the supernatant and algae residue were separated using Whatman The supernatant was filtered with No.1 filter paper to remove residual solid particles, and the supernatant was subjected to repeated operation 2 to 3 times to ensure sufficient centrifugation; the solvent of the filtered supernatant was evaporated using a rotary evaporator at 100 rpm and 50°C until the weight remained unchanged, thereby obtaining the active ingredient of green algae;

[0041] (3) Synthesis of SiO2 nanoparticles

[0042] The SiO2 precursor and deionized water are ultrasonically vibrated for 30 minutes to be diluted to 15wt%, and the pH of the precursor solution is adjusted to 7, and then the diluted SiO2 precursor solution is mixed with the microalgae active ingredient obtained in step (2) at a ratio of 5:1 (v:m), and the mixture is shaken in a constant temperature shaker at 45°C and 180rpm for 48h. After the shaking, the SiO2 nanoparticles are separated by centrifugation at 6000rpm for 10 minutes in a high-speed centrifuge, and purified to obtain SiO2 nanoparticles;

[0043] (4) Synthesis of Nanofluid Dust Suppressants

[0044] The SiO2 nanoparticles synthesized in step (3) are mixed with the green algae active ingredients and water in a ratio of 0.05wt%, and the concentrations of the nanoparticles and the microalgae active ingredients in the nanofluid are adjusted as needed. The mixing ratio is 0.01-0.15wt%, the ultrasonic dispersion time is 4-6h, the ultrasonic power is 180-200W, the ultrasonic temperature is 30-40°C, and the dispersant is a polycaprolactone polyol-polyethyleneimine block copolymer type dispersant to prepare a bio-based nanofluid dust suppressant.

[0045] The BG-11 culture medium in step (1) above comprises: 1.5 g / L NaNO3, 0.04 g / L K2HPO4·3H2O, 0.075 g / L MgSO4·7H2O, 0.036 g / L CaCl2·2H2O, 0.006 g / L citric acid, 0.006 g / L ammonium ferric citrate, 0.001 g / L ethylenediaminetetraacetic acid, 0.001 g / L 2Na-Mg salt, 0.02 g / L Na2CO3, 2.86 μg / L H3BO4, 1.81 μg / L MnCl2·4H2O, 0.222 μg / L ZnSO4·7H2O, 0.391 μg / L Na2MoO4·2H2O, 0.079 μg / L CuSO4·5H2O, 0.0494μg / LCo(NO3)2·6H2O, and the medium pH was finally adjusted to 7.4.

[0046] The purification treatment described in the above step (3) refers to evaporating the solvent from the filtered supernatant using a rotary evaporator, with the temperature of the rotary evaporator set at 50-65° C. and the speed set at 100 rpm to remove unreacted precursors and by-products.

[0047] Under the above conditions, the extraction rate of microalgae active ingredients reached 73.4%, the synthesis rate of SiO2 nanoparticles reached 85.2%, and the synthesis rate of nanofluid dust suppressants reached 84.7%.

[0048] The present invention is not limited to the above-mentioned embodiments. Those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing a microalgae-SiO2 bio-based nanofluid dust suppressant, characterized in that: The steps include: (1) Microalgae cultivation Prepare BG-11 culture medium according to the growth requirements of the selected microalgae, sterilize the BG-11 culture medium in a high-pressure steam sterilizer at 120°C for 30 minutes and return it to room temperature, inject 100 ml of the culture medium into 250 ml conical flasks, inoculate the selected microalgae, put them into a photobioreactor, and carry out light / dark continuous culture under certain temperature, light, pH, fixed carbon source and air conditions for 7 days. After the culture is completed, filter and collect the microalgae cells; (2) Extraction of active ingredients from microalgae The microalgae collected by filtration in step (1) are pretreated, the microalgae cells are washed with deionized water, the microalgae cell walls are crushed by ultrasonic wave after washing, the crushed microalgae cells are subjected to enzymatic hydrolysis for a certain time at a certain temperature, pH value and enzyme concentration, and then the enzymatically hydrolyzed microalgae cells are mixed with a mixed solution of chloroform and methanol, and microwave extraction is performed, the mixture after microwave extraction is centrifuged at 10000 rpm for 10 minutes to obtain a supernatant and algae residue, the supernatant is filtered with filter paper to remove residual solid particles, the operation is repeated 2 to 3 times, and the solvent of the filtered supernatant is evaporated with a rotary evaporator until the weight is constant, thereby obtaining the microalgae active ingredient; (3) Synthesis of SiO2 nanoparticles The SiO2 precursor is mixed with deionized water by ultrasonic oscillation for a certain period of time, diluted to an appropriate concentration, the pH value of the precursor solution is adjusted, and then the diluted SiO2 precursor solution is mixed with the microalgae active ingredient obtained in step (2) in a certain proportion, and the mixture is placed in a constant temperature oscillator and oscillated at a certain temperature and speed for a certain period of time. After the oscillation ends, SiO2 nanoparticles are centrifuged out by a high-speed centrifuge, and purified to obtain SiO2 nanoparticles; (4) Synthesis of Nanofluid Dust Suppressants The SiO2 nanoparticles synthesized in step (3) are mixed with microalgae active ingredients and water in proportion, and the concentrations of the SiO2 nanoparticles and microalgae active ingredients in the nanofluid are adjusted as needed. The microalgae-SiO2 bio-based nanofluid dust suppressant is prepared by ultrasonic dispersion and addition of a suitable dispersant.

2. The preparation method according to claim 1, characterized in that: In step (1), the microalgae is green algae; the BG-11 culture medium formula includes: 1.5g / L NaNO3, 0.04g / L K2HPO4·3H2O, 0.075g / L MgSO4·7H2O, 0.036g / L CaCl2·2H2O, 0.006g / L citric acid, 0.006g / L ammonium ferric citrate, 0.001g / L ethylenediaminetetraacetic acid, 0.001g / L 2Na-Mg salt, 0.02g / L Na2CO3, 2.86μg / L H3BO4, 1.81μg / L MnCl2·4H2O, 0.222μg / L ZnSO4·7H2O, 0.391μg / L Na2MoO4·2H2O, 0.079μg / L CuSO4·5H2O, 0.0494μg / L Co(NO3)2·6H2O, and the medium pH was finally adjusted to 7.

4.

3. The preparation method according to claim 1, characterized in that: In step (1), the photobioreactor is a light incubator; the culture temperature is optimized at 20-30°C; the light intensity is optimized at 5000-10000 lux; the pH value is optimized at pH 7.0-8.0; 10-15 ml of CO2 gas is introduced into the fixed carbon source per minute; 2.5 liters of air are blown into the air per minute per liter of culture solution; and the light / dark continuous culture time is 16 / 8 h.

4. The preparation method according to claim 1, characterized in that: In step (2), the ultrasonic crushing frequency is 20-40kHz, the power is 100-500W, and the crushing time is 5-15min; the temperature is 40-60°C; the pH is 4.5-6.0; the enzyme is one or both of cellulase and protease; the enzyme concentration is 0.1-1.5wt%, and the enzymolysis time is 1-4h.

5. The preparation method according to claim 1, characterized in that: In step (2), the chloroform and methanol solution has a chloroform:methanol ratio of 1.5 to 2.5:1 (V:V); the microwave power of the microwave extraction is 200 to 800 W, the frequency is 2.45 GHz, and the processing time is 15 to 30 min; the filter paper is Whatman No.1 filter paper; the temperature of the rotary evaporator is set to 50 to 65° C. and the rotation speed is 100 rpm.

6. The preparation method according to claim 1, characterized in that: In step (3), the SiO2 precursor is one of a sodium silicate solution and a potassium silicate solution; the ultrasonic oscillation time is 15 to 30 minutes; the dilution concentration is 15 to 20 wt%; the pH is adjusted to 7; and the mixing ratio of the SiO2 precursor solution to the microalgae active ingredient is 5 to 10:

1.

7. The preparation method according to claim 1, characterized in that: In step (3), the temperature of the constant temperature oscillator is 35-45°C, the oscillation time is 24-72h, and the oscillation speed is 180rpm; the speed of the high-speed centrifuge is 4000-8000rpm, and the centrifugation time is 10-15min; the purification treatment refers to using a rotary evaporator to evaporate the solvent of the filtered supernatant, and the temperature of the rotary evaporator is set to 50-65°C and the speed is 100rpm.

8. The preparation method according to claim 1, characterized in that: In step (4), the mixing ratio is 0.01-0.15 wt %, the ultrasonic dispersion time is 4-6 h, the ultrasonic power is 180-200 W, the ultrasonic temperature is 30-40° C., and the dispersant is a polycaprolactone polyol-polyethyleneimine block copolymer type dispersant.

9. The bio-based nanofluid dust suppressant according to any one of claims 1 to 8 is used by spraying, with a dosage of 0.1 to 0.5 kg / m2.

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