Preparation method and application of phenolic oil-based phase separation phenolic aerogel

Abstract

The invention discloses a preparation method and application of phenolic oil-based phase separation phenolic aerogel, and belongs to the field of high-value utilization of coal tar. The preparation method of the phase separation phenolic aerogel comprises the following steps: by taking melamine foam as a framework, carbolic oil, phenols and aldehydes as raw materials, mixing organic matters with different polarities as a solvent and acid as a catalyst, carrying out solvothermal reaction to obtain phase separation phenolic organogel; and drying in vacuum to obtain the phase separation phenolic aerogel. The phase separation phenolic aerogel with adjustable porosity and connectivity is obtained by adjusting the polarity and proportion of a mixed solvent, and the aerogel can be used for solar driven interface water evaporation. The phenolic aerogel with high connectivity is prepared by replacing phenols with the carbolic oil, so that the cost of raw materials is reduced, the utilization value of the carbolic oil is improved, meanwhile, the operation is simple, complex freeze drying and template pore adjustment are not needed, and the method has a good application prospect of solar-driven interface water evaporation.

Description

Technical Field

[0001] The invention belongs to the field of high-value utilization of coal tar, and specifically relates to a preparation method and application of phenol oil-based phase-separated phenolic aerogel. Background Art

[0002] Phenol oil is a complex mixture, mainly derived from byproducts of coal pyrolysis / coking process, rich in phenolic compounds and other aromatic harmful substances. At present, the separation and purification of phenolic compounds is the main method, but the process is complicated and produces a large amount of wastewater. Therefore, it is urgent to develop high-value and low-carbon utilization technologies for phenol oil. It can not only reduce environmental pollution, but also reduce resource waste and improve economic benefits.

[0003] Although about 70% of the earth's surface is covered by water, only about 3% of it is fresh water, and a large part of this fresh water (about 87%) is frozen in glaciers and ice caps and is difficult to use. Therefore, the fresh water resources on the earth that can be directly used by humans are very limited, and the growth of population and economic activities will further aggravate the global water shortage. In order to solve this world problem, seawater desalination is one of the most effective methods. At present, seawater desalination technology mainly includes multi-stage flash evaporation and reverse osmosis, but these methods have problems of high energy consumption, large investment or difficulty in scale. Therefore, solar-driven interfacial water evaporation technology with the advantages of high energy efficiency and zero carbon emissions has attracted widespread attention. Among them, aerogel is widely used in solar-driven interfacial water evaporation due to its advantages such as high porosity, low thermal conductivity and low density.

[0004] Among them, the preparation of phenolic aerogels requires a large amount of phenol, which is costly. Therefore, it is of great significance to find a substitute for phenol. Given that phenol oil is rich in a variety of phenolic compounds, it is expected to replace phenol to prepare phenolic aerogels. Moreover, phenolic oil substitution can enhance photothermal performance without the need to add expensive light absorbers, further reducing costs. In addition, the connectivity of the pores has a great influence on the water evaporation performance of the aerogel, and the development of highly connected phenolic oil-based phase-separated phenolic aerogels is of great significance. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation method and application of phenol oil-based phase-separated phenolic aerogel, using cheap phenol oil to replace part of the petrochemical raw material phenol to synthesize phase-separated phenolic aerogel with high photothermal conversion performance and fast water escape, providing a new way for the high-value utilization of phenol oil and aerogel pore modulation, and at the same time, the aerogel can be used in solar-driven interfacial water evaporation and achieve good results.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a phenol oil-based phase-separated phenolic aerogel comprises the following steps:

[0008] 1) adding phenols and phenol oil into a mixed solvent, stirring until dissolved, to obtain a mixed solution;

[0009] 2) placing melamine foam into the above solution, and then adding aldehydes and acids to obtain a mixed sol;

[0010] 3) subjecting the mixed sol to a solvothermal reaction to obtain a phase-separated phenol oil-based phenolic organic gel;

[0011] 4) washing the phenolic organic gel with ethanol and then vacuum drying to obtain a phase-separated phenol oil-based phenolic organic aerogel.

[0012] Furthermore, the mixed solvent in step (1) is a mixture of two selected from methanol, ethanol, isopropanol, n-butanol, isobutanol, and acetone, and the volume ratio of the two is 0:1-1:0; the phenol is one of phenol, o-cresol, m-cresol, p-cresol, p-ethylphenol, and resorcinol; and the mass ratio of the phenol oil to the phenol is 1:9-1:1.

[0013] Furthermore, in step (2), the aldehyde is one or two of formaldehyde, paraformaldehyde, and furfural; and the acid is one of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, and oxalic acid.

[0014] Furthermore, the ratio of phenol, mixed solvent, aldehyde and acid in steps (1) and (2) is 0.8-1.44 g: 10-50 mL: 1.5-8.5 mL: 0.5-2.5 mL.

[0015] Furthermore, in step (3), the solvent thermal reaction temperature is 80-160°C and the time is 6-36h.

[0016] It should be further explained that based on the differences in solvent polarity and the solubility of phenolic resin in different solvents, by adjusting the type and proportion of solvents, a phenol oil-based phase-separated phenolic aerogel with interconnected pores can be obtained to achieve high porosity and high connectivity.

[0017] Another object of the present invention is to provide an application of the phenol oil-based phase-separated phenolic aerogel obtained by the above preparation method in solar-driven interfacial water evaporation.

[0018] Beneficial effects of the present invention:

[0019] 1. The method for preparing the phenol oil-based phase-separated phenolic aerogel with high connectivity is simple and does not require complicated freeze drying and templates.

[0020] 2. The present invention prepares phase-separated phenolic aerogel by replacing part of phenol with phenol oil to enhance the photothermal performance without the need to add additional light absorbers.

[0021] 3. The present invention uses melamine foam as a skeleton and a mixture of two organic substances of different polarities as a solvent to prepare phenol oil-based phase-separated phenolic aerogel, thereby enhancing the mechanical properties of the phenolic aerogel.

[0022] 4. Phenol oil is mainly used as a raw material for extracting phenol in industrial production. The process is complicated, the purification is difficult, and it pollutes the environment. The present invention replaces part of phenols with phenol oil to prepare phenolic aerogel, which not only improves the utilization value of phenolic oil, but also replaces photothermal materials, reduces the cost of raw materials, and improves the solar-driven water evaporation performance of conventional phenolic aerogel, thus having good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] Figure 1 This is a physical photo of the aerogel in Example 1 of the present invention.

[0025] Figure 2 Optical microscope photographs of aerogels in Examples 1-5 of the present invention: (a) CPA-et, (b) CPA-buty, (c) CPA-isop, (d) CPA-et+buty and (e) CPA-et+isop.

[0026] Figure 3 1 is the stress-strain curve of the aerogel in Examples 2-4 of the present invention.

[0027] Figure 4 It is the saturated water content and water transmission rate of the aerogel in Examples 1-5 of the present invention.

[0028] Figure 5 The solar-driven water evaporation performance of the aerogels in Examples 1-5 of the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Embodiment 1

[0031] 1.12 g of phenol and 0.48 g of phenol oil (phenol substitution rate of 30%) were weighed, added to 30 mL of organic solvent (ethanol / n-butanol = 1:1), and stirred until dissolved to obtain a mixed solution; melamine foam (diameter 3.5 cm, height 4 cm) was placed in the above solution, and then 5 mL of formaldehyde (35 wt %) and 1.5 mL of hydrochloric acid (37 wt %) were added to obtain a mixed sol; the above mixed sol was subjected to a solvothermal reaction at 120° C. for 12 h to obtain a phenol oil-based phase-separated phenolic organic gel; the above phenolic organic gel was washed with ethanol until the washing liquid was colorless, and then vacuum dried to obtain a phenol oil-based phase-separated phenolic organic aerogel (CPA-et+buty, Figure 1 ). Density is 0.061g / cm 3 , the phenolic resin balls are unevenly distributed ( Figure 2 ). When the strain is 90%, the compressive strength is 1.63MPa ( Figure 3 ). The saturated water content is 13g·g -1 , water transmission rate is 0.082g·min -1 ( Figure 4 ). Under 1 times the sunlight, the water evaporation rate is 2.09 kg·m -2 h -1 ( Figure 5 ), which is 4.5 times that of pure water.

[0032] Embodiment 2

[0033] Weigh 0.8g of m-cresol and 0.8g of phenol oil (m-cresol substitution rate is 50%), add them to 30mL of ethanol, stir until dissolved, and obtain a mixed solution; put melamine foam (diameter 3.5cm, height 4cm) into the above solution, and then add 5mL of formaldehyde (35wt%) and 1.5mL of hydrochloric acid (37wt%) to obtain a mixed sol; the above mixed sol is subjected to solvent thermal reaction at 140°C for 12h to obtain a phenol oil-based phenolic organic gel; wash the phenolic organic gel with ethanol until the washing liquid is colorless, and then vacuum dry to obtain a phenol oil-based phenolic organic aerogel (CPA-et). The density is 0.060g / cm 3 , the number of phenolic resin balls is small and evenly distributed ( Figure 2 ). When the strain is 90%, the compressive strength is 0.57MPa ( Figure 3 ). Saturated water content is 12g·g -1 , water transmission rate is 0.066g·min -1 ( Figure 4 ). Under 1 times the sunlight, the water evaporation rate is 1.81 kg·m -2 h -1 ( Figure 5 ), which is 3.9 times that of pure water, but significantly lower than that of phenol oil-based phase-separated phenolic aerogel.

[0034] Embodiment 3

[0035] Weigh 1.12g phenol and 0.48g phenol oil (phenol replacement rate is 30%), add them to 30mL n-butanol, stir until dissolved, and obtain a mixed solution; put melamine foam (diameter 3.5cm, height 4cm) into the above solution, and then add 5mL formaldehyde (35wt%) and 1.5mL hydrochloric acid (37wt%) to obtain a mixed sol; the above mixed sol is subjected to solvent thermal reaction at 120℃ for 12h to obtain a phenol oil-based phenolic organic gel; wash the above phenolic organic gel with ethanol until the washing liquid is colorless, and then vacuum dry to obtain a phenol oil-based phenolic organic aerogel (CPA-buty). The density is 0.064g / cm 3 . The number of phenolic resin balls is large and evenly distributed ( Figure 2 ). When the strain is 90%, the compressive strength is 0.43MPa ( Figure 3 ). The saturated water content is 11g·g -1 , water transmission rate is 0.048g·min -1 ( Figure 4 ). Under 1 times the sunlight, the water evaporation rate is 1.71 kg·m -2 h -1 ( Figure 5 ), which is 3.7 times that of pure water.

[0036] Embodiment 4

[0037] Weigh 1.12g phenol and 0.48g phenol oil (phenol replacement rate 30%), add to 30mL isopropanol, stir until dissolved, and obtain a mixed solution; put melamine foam (diameter 3.5cm, height 4cm) into the above solution, then add 8mL formaldehyde (35wt%) and 1.5mL hydrochloric acid (37wt%) to obtain a mixed sol; the above mixed sol is subjected to solvent thermal reaction at 100℃ for 12h to obtain a phenol oil-based phenolic organic gel; wash the above phenolic organic gel with ethanol until the washing liquid is colorless, and then vacuum dry to obtain a phenol oil-based phenolic organic aerogel (CPA-isop). The density is 0.063g / cm 3 , the number of phenolic resin balls is large and evenly distributed ( Figure 2 ). When the strain is 90%, the compressive strength is 0.14MPa ( Figure 3 ). The saturated water content is 11g·g -1 , water transmission rate is 0.058g·min -1 ( Figure 4 ). Under 1 times the sunlight, the water evaporation rate is 1.76 kg·m -2 h -1 ( Figure 5 ).

[0038] Embodiment 5

[0039] Weigh 1.12g phenol and 0.48g phenol oil (phenol substitution rate is 10%), add them to 40mL organic solvent (ethanol / isopropanol = 1:1), stir until dissolved, and obtain a mixed solution; put melamine foam (diameter 3.5cm, height 5cm) into the above solution, and then add 5mL formaldehyde (35wt%) and 2mL hydrochloric acid (37wt%) to obtain a mixed sol; the above mixed sol is subjected to solvent thermal reaction at 120℃ for 18h to obtain a phenol oil-based phase-separated phenolic organic gel; wash the above phenolic organic gel with ethanol until the washing liquid is colorless, and then vacuum dry to obtain a phenol oil-based phase-separated phenolic organic aerogel (CPA-et+isop). The density is 0.043g / cm 3 , the phenolic resin balls are unevenly distributed ( Figure 2 ). When the strain is 90%, the compressive strength is 4.3MPa ( Figure 3 ). The saturated water content is 13g·g -1 , water transmission rate is 0.078g·min -1 ( Figure 4 ). Under 1 times the sunlight, the water evaporation rate is 2.01kg·m -2 h -1 ( Figure 5 ).

[0040] The above specific implementation method part specifically introduces the analytical method involved in the present invention. It should be noted that the above introduction is only to help those skilled in the art better understand the method and ideas of the present invention, rather than limiting the relevant content. Without departing from the principle of the present invention, those skilled in the art may also make appropriate adjustments or modifications to the present invention, and the above adjustments and modifications shall also fall within the scope of protection of the present invention.

Claims

1. A method for preparing a phenol oil-based phase-separated phenolic aerogel, characterized in that: The following steps are involved: 1) adding phenols and phenol oil into a mixed solvent, stirring until dissolved, to obtain a mixed solution; 2) placing melamine foam into the above solution, and then adding aldehydes and acids to obtain a mixed sol; 3) subjecting the mixed sol to a solvothermal reaction to obtain a phase-separated phenol oil-based phenolic organic gel; 4) washing the phenolic organic gel with ethanol and then vacuum drying to obtain a phase-separated phenol oil-based phenolic organic aerogel.

2. The method for preparing a phenol oil-based phase separation phenolic aerogel according to claim 1, characterized in that: The mixed solvent in step (1) is a mixture of two selected from methanol, ethanol, isopropanol, n-butanol, isobutanol, and acetone, and the volume ratio of the two is 0:1-1:0; the phenol is one of phenol, o-cresol, m-cresol, p-cresol, p-ethylphenol, and resorcinol; and the mass ratio of the phenol oil to the phenol is 1:9-1:

1.

3. The method for preparing a phenol oil-based phase separation phenolic aerogel according to claim 1, characterized in that: In step (2), the aldehyde is one or two of formaldehyde, paraformaldehyde and furfural; and the acid is one of hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid and oxalic acid.

4. The method for preparing a phenol oil-based phase separation phenolic aerogel according to claim 1, characterized in that: The ratio of phenol, mixed solvent, aldehyde and acid in steps (1) and (2) is 0.8-1.44 g:10-50 mL:1.5-8.5 mL:0.5-2.5 mL.

5. The method for preparing a phenol oil-based phase separation phenolic aerogel according to claim 1, characterized in that: In step (3), the solvent thermal reaction temperature is 80-160°C and the time is 6-36h.

6. Application of the phenol oil-based phase-separated phenolic aerogel obtained according to the preparation method according to any one of claims 1 to 5 in solar-driven interfacial water evaporation.

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