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

Abstract

The present invention provides a method for preparing a microalgae-SiO2 bio-based nanofluid dust suppressant, comprising the following steps: (1) microalgae cultivation: using BG-11 culture medium, sterilizing and cooling, inoculating microalgae, carrying out 7-day light / dark cycle cultivation, and finally filtering and collecting microalgae cells; (2) active ingredient extraction: washing the microalgae cells, and extracting the microalgae active ingredients through ultrasonic crushing, enzymatic hydrolysis and microwave-assisted chloroform-methanol mixed extraction, centrifugation, filtration and rotary evaporation; (3) SiO2 nanoparticle synthesis: mixing a SiO2 precursor with deionized water, adjusting the pH and diluting, adding the microalgae active ingredients and shaking at a constant temperature, centrifuging and purifying the SiO2 nanoparticles; (4) nanofluid dust suppressant preparation: mixing SiO2 nanoparticles, microalgae active ingredients and a dispersant in water in proportion to prepare a microalgae-SiO2 bio-based nanofluid dust suppressant. The invention is expected to address the limitations of traditional dust suppressants and provide a new, efficient and environmentally friendly method for preparing dust suppressants.

Description

Technical Field

[0001] The present 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 prevention and control has become an important issue in the fields of environmental protection and public health. Traditional dust prevention and 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, there is an urgent need to develop a high-performance, non-toxic and harmless, high-efficiency and environmentally friendly dust suppressant.

[0003] Nanofluids, a novel dust suppression technology, have garnered widespread attention in the dust control field in recent years. Nanofluids, typically composed of nanometer-sized solid particles dispersed in a liquid medium, possess unique physicochemical properties, such as high surface area, excellent dispersibility, and stability. However, existing nanofluid dust suppressants have primarily focused on single components, resulting in poor wetting, bonding, and moisture retention properties, which in turn limits their effectiveness.

[0004] As a photosynthetic organism, microalgae has the characteristics of fast growth, large biomass, and easy cultivation. In addition, they can produce a variety of bioactive substances through their 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, by synergizing microalgae with SiO2 nanofluids to prepare microalgae-SiO2 bio-based nanofluid dust suppressants, not only can the bioactive substances produced by microalgae metabolism compensate 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 address 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 problems solved

[0006] The present invention addresses the shortcomings of current technologies by providing a method for preparing a microalgae-SiO2 bio-based nanofluid dust suppressant. This method addresses the high cost, poor dust suppression effectiveness, environmental unfriendliness, and poor biodegradability of existing dust suppressants. The microalgae-SiO2 bio-based nanofluid dust suppressant of the present invention exhibits good biodegradability, is non-toxic, low-cost, has excellent dust suppression effectiveness, is biocompatible and safe, and is multifunctional.

[0007] (2) Technical solution

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

[0009] The preparation method of 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 then cool it to room temperature. Pour 100 ml of the culture medium into 250 ml conical flasks, inoculate the selected microalgae, and place them in a photobioreactor. Continuous light / dark culture is carried out for a certain period of time under certain temperature, light, pH, fixed carbon source, and air conditions. After the culture is completed, the microalgae cells are filtered and collected.

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

[0013] The microalgae collected by filtration in step (1) are pretreated, and the microalgae cells are washed with deionized water to remove culture medium residues and impurities; the washed microalgae are subjected to ultrasonic wave to break the microalgae cell walls to release the active components in the cells, and the broken 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, where microwave heating can accelerate solvent penetration and active component release; the mixture after microwave extraction is centrifuged to obtain a supernatant and algae residue, the supernatant is filtered with filter paper to remove residual solid particles, and the solvent is evaporated from the filtered supernatant using 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 ultrasonically shaken and mixed with deionized water for a certain period of time, diluted to an appropriate concentration, and the pH value of the precursor solution is adjusted. 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 shaker and shaken at a certain temperature and speed for a certain period of time. After the shaking is completed, the 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 an appropriate 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 / LCaCl2·2H2O, 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 / LCuSO4·5H2O, 0.0494μg / L Co(NO3)2·6H2O, and the final pH of the culture medium was 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 is 2.5 liters of air per minute per liter of culture solution; and the light / dark ratio is 16 L / 8 D continuous culture.

[0020] In the above step (2), the ultrasonic crushing frequency is 20-40 kHz, the power is 100-500 W, and the crushing time is 5-15 minutes; 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 0.1-1.5 wt%, and the enzymatic hydrolysis time is 1-4 hours, so that the active ingredients in the microalgae cells are fully released.

[0021] In the above step (2), the chloroform and methanol solution 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 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 prepared 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 constant temperature oscillator temperature is 35-45°C, the oscillation time is 24-72h, and the oscillation speed is 180rpm; the high-speed centrifuge speed is 4000-8000rpm, and the centrifugation time is 10-15min; the purification treatment refers to using a rotary evaporator to evaporate the solvent from the filtered supernatant, and the rotary evaporator temperature 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 to 0.15 wt %, the ultrasonic dispersion time is 4 to 6 h, the ultrasonic power is 180 to 200 W, the ultrasonic temperature is 30 to 40° C., and the dispersant is a polycaprolactam polyol-polyethyleneimine block copolymer 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, with a dosage of 0.1 to 0.5 kg / m2.

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

[0027] (3) 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 environmental pollution. At the same time, the low toxicity of microalgae and SiO2 ensures its safety for humans and ecosystems, promoting sustainable environmental development.

[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 dust suppression efficiency. This nanoscale effect enables the dust suppressant to work in a wider range of particle sizes, including ultrafine dust. The synergistic effect of the microalgae active ingredients and SiO2 nanoparticles improves the wettability and adhesion to dust particles, making it easier for the dust suppressant to penetrate the surface of the dust particles, forming a stable coating layer to prevent 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 dust-prone locations such as mines and construction sites, but can also be applied to various scenarios 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 effects that the microalgae active ingredients may bring provide the dust suppressant with multifunctionality. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0033] To facilitate understanding of the present invention, the present invention will be described more fully below through examples, with preferred embodiments of the present invention provided 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 embodiments obtained by modifying or equivalently replacing the technical solution of the present invention without inventive results are within the scope of protection of the present invention.

[0034] The numerical values ​​disclosed in the embodiments of the present invention are approximate values, not definite values. Where errors 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 the medium in a high-pressure steam autoclave at 120°C for 30 minutes and allow it to cool to room temperature. Pour 100 ml of the culture medium into 250 ml conical flasks, inoculate the selected microalgae, and place the flasks in a light incubator. Cultivate the culture medium continuously under a light / dark cycle of 16 L / 8 D at 25°C, 8000 lux, pH 7.0, with 10 ml of CO2 per minute and 2.5 liters of air per minute per liter of culture medium for 7 days. After the incubation period, collect the green algae cells by filtration.

[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 pH of the solution 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 using No. 1 filter paper to remove residual solid particles, and the supernatant was centrifuged 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 the green algae.

[0041] (3) Synthesis of SiO2 nanoparticles

[0042] The SiO2 precursor and deionized water were ultrasonically vibrated for 30 minutes to be diluted to 15wt%, and the pH of the precursor solution was adjusted to 7. The diluted SiO2 precursor solution was then mixed with the microalgae active ingredient obtained in step (2) at a ratio of 5:1 (v:m). The mixture was shaken in a constant temperature shaker at 45°C and 180 rpm for 48 hours. After the shaking, the mixture was centrifuged in a high-speed centrifuge at 6000 rpm for 10 minutes to separate the SiO2 nanoparticles, and then 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 dispersant to prepare a bio-based nanofluid dust suppressant.

[0045] The BG-11 culture medium in step (1) above includes: 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 final pH of the culture medium was adjusted to 7.4.

[0046] The purification treatment described in the above step (3) refers to evaporating the solvent of the filtered supernatant using a rotary evaporator, with the rotary evaporator temperature set at 50-65° C. and the rotation 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 embodiments. Those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to these 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 medium according to the growth requirements of the selected microalgae, sterilize the medium in a high-pressure steam sterilizer at 120°C for 30 minutes, and then cool to room temperature. Pour 100 ml of the medium into 250 ml conical flasks, inoculate the selected microalgae, and place them in a photobioreactor. Continuous light / dark culture is carried out under certain temperature, light, pH, fixed carbon source, and air conditions for 7 days. After the culture is completed, the microalgae cells are filtered and collected. (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, the crushed microalgae cells are enzymatically hydrolyzed 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, microwave extracted, and 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 remains unchanged, thereby obtaining the microalgae active ingredient; (3) Synthesis of SiO2 nanoparticles The SiO2 precursor is ultrasonically shaken and mixed with deionized water for a certain period of time, diluted to an appropriate concentration, and the pH value of the precursor solution is adjusted. 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 shaker and shaken at a certain temperature and speed for a certain period of time. After the shaking is completed, the 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 the 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 an appropriate 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 / LCaCl2·2H2O, 0.006g / L citric acid, 0.006g / L ammonium ferric citrate, 0.001g / L ethylenediaminetetraacetic acid, 0.001g / L2Na-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 final pH of the culture medium was 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 culture medium per minute; and the light / dark continuous culture time is 16 / 8 hours.

4. The preparation method according to claim 1, characterized in that In step (2), the ultrasonic crushing frequency is 20-40 kHz, the power is 100-500 W, and the crushing time is 5-15 min; 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 0.1-1.5 wt%, and the enzymatic hydrolysis time is 1-4 h.

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 constant temperature oscillator temperature is 35-45°C, the oscillation time is 24-72h, and the oscillation speed is 180rpm; the high-speed centrifuge speed is 4000-8000rpm, and the centrifugation time is 10-15min; the purification treatment refers to using a rotary evaporator to evaporate the solvent from the filtered supernatant, and the rotary evaporator temperature 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 polycaprolactam polyol-polyethyleneimine block copolymer 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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