阅读说明：本技术 一种复合生物质气凝胶光热转换材料的制备方法及其应用 (Preparation method and application of composite biomass aerogel photothermal conversion material ) 是由 苗蕾 顾宇飞 周建华 王鹏飞 于 2018-07-23 设计创作，主要内容包括：本发明公开了一种复合生物质气凝胶光热转换材料的制备方法,将废弃的生物质材料回收利用,通过碳化、研磨和过筛后与壳聚糖溶液混合制备光热转换气凝胶复合材料,制备工艺简单,成本低廉,得到的材料无毒、可降解、绿色环保,具有高效的太阳能蒸汽效率,满足当今可持续发展的要求,可用于海水淡化和污水处理,具有广泛应用前景。(The invention discloses a preparation method of a composite biomass aerogel photothermal conversion material, which is characterized in that waste biomass materials are recycled, carbonized, ground and sieved and then mixed with a chitosan solution to prepare the photothermal conversion aerogel composite material.)

1. The preparation method of the composite biomass aerogel photothermal conversion material is characterized by comprising the following steps:

1) drying the waste biomass material at 60-100 ℃, carbonizing at 300-900 ℃, grinding, and sieving with a 120-mesh sieve to obtain biomass carbon powder;

2) dissolving chitosan powder in 2 wt% acetic acid solution to prepare 1-2 wt% chitosan solution;

3) mixing the biomass carbon powder obtained in the step 1) and the chitosan solution obtained in the step 2) according to a mass ratio of 1: 10-40, mixing, and placing in a freeze dryer for freeze drying or supercritical drying for 30-40 h to prepare the biomass aerogel; and then neutralizing and curing the mixture by 0.1-0.5 mol/L ammonia water or NaOH solution, and cleaning the mixture to be neutral by using deionized water to obtain the composite biomass aerogel photothermal conversion material.

2. The method for preparing the composite biomass aerogel photothermal conversion material according to claim 1, wherein the biomass material of step 1) is selected from any one of roots, stems, leaves, seeds, fruit peels and fruits of plants.

3. The preparation method of the composite biomass aerogel photothermal conversion material according to claim 2, wherein the fruit peel is selected from any one of shaddock peel, coconut shell, banana peel and watermelon peel.

4. The preparation method of the composite biomass aerogel photothermal conversion material according to claim 1, wherein when the biomass material is selected from shaddock peel, the step 1) is: putting the waste shaddock peels into a forced air drying oven for drying at a constant temperature of 60-100 ℃, weighing 5-10 g of the dried shaddock peels, putting the weighed shaddock peels into a vacuum tube furnace, introducing nitrogen as protective gas at a flow rate of 20sccm, carbonizing the shaddock peels at a temperature of 500-900 ℃ respectively at a heating rate of 1-5 ℃/min, and preserving heat for 3-5 hours; the carbonized shaddock peels with different carbonization temperatures are ground by an agate mortar and sieved by a 120-mesh stainless steel screen.

5. The use of the composite biomass aerogel photothermal conversion material obtained in claim 1, characterized by being used for desalination of sea water and treatment of sewage.

The technical field is as follows:

the invention relates to the technical field of solar photo-thermal conversion, in particular to a preparation method and application of a composite biomass aerogel photo-thermal conversion material.

Background art:

at present, in order to solve the increasingly deficient energy crisis, people propose a sustainable development strategy, seek renewable and environment-friendly energy and focus on various forms of energy such as solar energy, wind energy, tide, geothermal heat and the like; at present, research on solar photo-thermal conversion materials becomes a hotspot, and the solar energy is converted into heat energy to locally heat water by utilizing the photo-thermal conversion materials, so that drinkable fresh water is obtained, and the method has quite considerable application prospect; the total reserve of water resources on the earth is 14 hundred million cubic kilometers, however, the reserve of fresh water resources only accounts for 2.53 percent of the total reserve, 68.7 percent of the reserve of fresh water resources belongs to solid glaciers, and is distributed in alpine, south and north polar regions which are difficult to utilize, and a part of fresh water is buried in places which are deep underground, so that the fresh water resources are difficult to exploit, and along with the continuous modernization process of human society, the precious fresh water resources are polluted, and the fresh water resources left for human are very limited, thereby restricting the survival and development of human beings.

Therefore, the research of the photothermal conversion material is very accordant with the requirement of the times, and the photothermal material researched at present mainly comprises noble metal nano particles, carbon-based nano materials, some black nano semiconductors and some high polymer materials with good absorption capacity for visible light; however, most of the photothermal conversion materials have complicated synthesis methods, high cost, and by-products and the by-products are harmful to the environment, so that the wide application of the materials is limited.

The invention content is as follows:

the invention aims to provide a preparation method of a composite biomass aerogel photothermal conversion material, which is characterized in that waste biomass materials are recycled, and the waste biomass materials are carbonized, ground and sieved and then are compounded with chitosan to prepare the composite biomass aerogel photothermal conversion material.

The invention is realized by the following technical scheme:

a preparation method of a composite biomass aerogel photothermal conversion material comprises the following steps:

1) drying the waste biomass material at 60-100 ℃, carbonizing at 300-900 ℃, grinding, and sieving with a 120-mesh sieve to obtain biomass carbon powder;

2) dissolving chitosan powder in 2 wt% acetic acid solution to prepare 1-2 wt% chitosan solution;

3) mixing the biomass carbon powder obtained in the step 1) and the chitosan solution obtained in the step 2) according to a mass ratio of 1: 10-40, mixing, and placing in a freeze dryer for freeze drying or supercritical drying for 30-40 h to prepare the biomass aerogel; and then neutralizing and curing the mixture by 0.1-0.5 mol/L ammonia water or NaOH solution, and cleaning the mixture to be neutral by using deionized water to obtain the composite biomass aerogel photothermal conversion material.

The biomass material in the step 1) is any one of pericarps such as shaddock peel, coconut shell, banana peel and watermelon peel, roots, stems, leaves, seeds and fruits of plants.

In particular, when the biomass material is selected from grapefruit peel, step 1) is preferably: putting the waste shaddock peels into a forced air drying oven for drying at a constant temperature of 60-100 ℃, weighing 5-10 g of the dried shaddock peels, putting the weighed shaddock peels into a vacuum tube furnace, introducing nitrogen as protective gas at a flow rate of 20sccm, carbonizing the shaddock peels at a temperature of 500-900 ℃ respectively at a heating rate of 1-5 ℃/min, and preserving heat for 3-5 hours; the carbonized shaddock peels with different carbonization temperatures are ground by an agate mortar and sieved by a 120-mesh (125 mu m) stainless steel screen.

The invention also protects the application of the composite biomass aerogel photothermal conversion material for seawater desalination and sewage treatment.

The invention has the following beneficial effects:

1. the invention has the advantages of low cost, wide raw materials, simple preparation process, large-scale production and hopeful industrial production.

2. The composite biomass aerogel photothermal conversion material obtained by the invention is double-layer, has good hydrophilicity, achieves a local heat collection effect by performing efficient photothermal conversion through a biomass carbon powder layer, has a disordered and porous structure on the surface, is favorable for the escape of water vapor, and has a multi-stage structure for increasing multiple scattering of light and being favorable for the absorption of light; the chitosan aerogel layer plays a role in heat insulation and ensuring sufficient water supply, and efficient water evaporation is realized.

3. The composite biomass aerogel photothermal conversion material obtained by the invention has good light absorption performance, and the sunlight absorption rate in the range of 250-2500 nm reaches more than 90%.

4. The composite biomass aerogel photothermal conversion material obtained by the invention is 1kW m^-2Under the sunlight intensity, the highest photo-thermal steam efficiency can reach 90.4 percent.

5. The composite biomass aerogel photothermal conversion material obtained by the invention can be used for sewage treatment, seawater desalination and the like.

In a word, the waste biomass material is recycled, the composite biomass aerogel photothermal conversion material is prepared by compounding the carbonized, ground and screened chitosan, the cost is low, the raw materials are wide, the preparation process is simple, large-scale production can be realized, the obtained double-layer composite biomass aerogel photothermal conversion material is non-toxic, degradable, green and environment-friendly, the hydrophilicity is good, the local heat collection effect is achieved by efficient photothermal conversion through a biomass carbon powder layer, the disordered porous structure on the surface is favorable for escape of water vapor, the multiple scattering of light is increased through the multi-stage structure, and the light absorption is facilitated; the chitosan aerogel layer plays a role in heat insulation and ensures sufficient water supply, and efficient water evaporation is realized; the sunlight absorption rate of the coating reaches more than 90 percent within the range of 250-2500 nm, and the coating is 1kW m^-2The highest photo-thermal steam efficiency can reach 90.4% under the sunlight intensity, the requirement of the current sustainable development is met, and the solar energy-saving solar water heater can be used for sewage treatment and seawater desalination and has wide application prospect.

Description of the drawings:

FIG. 1 is a scanning electron microscope image of the microstructure of the composite biomass aerogel photothermal conversion material obtained in example 1;

fig. 2 is a graph of an ultraviolet/visible/near-infrared absorption spectrum of the composite biomass aerogel photothermal conversion material obtained in example 1;

FIG. 3 is a scanning electron microscope image of the microstructure of the composite biomass aerogel photothermal conversion material obtained in example 2;

fig. 4 is a graph of the ultraviolet/visible/near-infrared absorption spectrum of the composite biomass aerogel photothermal conversion material obtained in example 2;

FIG. 5 is a scanning electron microscope image of the microstructure of the composite biomass aerogel photothermal conversion material obtained in example 3;

fig. 6 is a graph of the ultraviolet/visible/near-infrared absorption spectrum of the composite biomass aerogel photothermal conversion material obtained in example 3;

FIG. 7 is a scanning electron microscope image of the microstructure of the composite biomass aerogel photothermal conversion material obtained in example 4;

fig. 8 is a graph of the ultraviolet/visible/near-infrared absorption spectrum of the composite biomass aerogel photothermal conversion material obtained in example 4;

FIG. 9 is a schematic cross-sectional view of the homemade steam test facility of example 5;

wherein, 1, a polyethylene foam layer, 2, a water storage container, 3, dust-free fiber paper, 4 and a groove;

FIG. 10 shows that the composite biomass aerogel photothermal conversion material obtained in example 6 and example 3 is at 1kWm^-2Under the light intensity, a 3.5 wt% NaCl solution is used for simulating a seawater desalination evaporation rate diagram.

The specific implementation mode is as follows:

the following is a further description of the invention and is not intended to be limiting.