A thermosensitive photothermal pollen adsorbent and its preparation method

Abstract

This invention provides a thermosensitive photothermal pollen adsorbent and its preparation method. The raw materials for preparing the adsorbent include: pollen, N-isopropylacrylamide, pyrrole, lithium chloride, N-isopropylacrylamide polymerization initiator I and pyrrole polymerization initiator II. The N-isopropylacrylamide is grafted onto the pollen surface through polymerization to form grafted pollen, and the pyrrole is loaded onto the grafted pollen surface through polymerization. The thermosensitive photothermal pollen adsorbent and its preparation method of this invention have the advantages of high adsorption, low-temperature regeneration performance at 40-50℃, good photothermal conversion ability, and economy.

Description

Technical Field

[0001] This invention relates to the field of adsorption water extraction technology, specifically to a thermosensitive photothermal pollen adsorbent and its preparation method. Background Technology

[0002] Freshwater resources, like air, are essential for human survival. With rapid global economic development and explosive population growth, the demand for freshwater resources has increased dramatically. Furthermore, in many parts of the world, insufficient awareness of water conservation has led to severe waste and pollution of freshwater resources, making already scarce freshwater resources even more limited. The atmosphere contains a vast amount of water, approximately 12.9 × 10³ km³. 3 This is approximately six times the total amount of water in rivers on Earth. Therefore, obtaining water by absorbing water from the air can compensate for the shortage of freshwater resources and is of great significance for alleviating global water shortages.

[0003] Adsorption / absorption-based air-to-water extraction uses hygroscopic adsorbents / absorbents to capture water vapor molecules in the air and store them in the absorbent material. After a period of time, the adsorbent / absorbent is regenerated by heating, causing the water vapor to be released again. After condensation, fresh water is obtained. Because the partial pressure of water vapor in the atmosphere is low, direct cooling requires a relatively low condensation temperature. However, after the adsorption-desorption process, the partial pressure of water vapor in the desorbed humid air is greatly increased. Therefore, the adsorption / absorption system essentially increases the partial pressure of water vapor in the air, i.e., increases the dew point. Compared with direct cooling water extraction, at the same condensation temperature, adsorption / absorption-based water extraction consumes less energy, has higher water extraction efficiency, and a wider range of applications, showing great promise for future applications.

[0004] Currently, commonly used water vapor adsorbents include zeolites, silica gel, metal-organic frameworks, and hygroscopic salts. In practice, adsorbent powder is typically stacked to form an adsorption bed for water extraction. Therefore, the key to adsorption / absorption air extraction technology lies in the characteristics of the adsorbent used in the system. A review of existing technologies reveals that hygroscopic composite materials, such as porous materials + salt, polymers + salt, and polymers + polymers, are frequently used in adsorption air extraction systems. Among these, porous materials + salt and polymers + salt composites exhibit high adsorption performance but require higher regeneration heat source temperatures. While polymers + polymers composites possess both high adsorption performance and low-temperature desorption capabilities, their economic efficiency and photothermal conversion performance are poor. These shortcomings significantly limit the development and widespread adoption of adsorption air extraction technology.

[0005] Therefore, providing an air-to-water adsorbent that simultaneously possesses high adsorption performance, low-temperature desorption performance, good photo-thermal conversion, and economic efficiency is one of the technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0006] To address the shortcomings of composite adsorbents used in adsorption-type air-to-water systems, this invention designs a thermosensitive photothermal pollen adsorbent and its preparation method, providing adsorption-type air-to-water systems with a composite adsorbent that combines high-efficiency adsorption, rapid desorption, good photo-thermal conversion capability, and economic efficiency.

[0007] To address the aforementioned problems, this invention discloses a thermosensitive photothermal pollen adsorbent. The raw materials for preparing the adsorbent include: pollen, N-isopropylacrylamide, pyrrole, lithium chloride, N-isopropylacrylamide polymerization initiator I and pyrrole polymerization initiator II. The N-isopropylacrylamide is polymerized and grafted onto the pollen surface to form grafted pollen, and the pyrrole is loaded onto the grafted pollen surface through a polymerization reaction.

[0008] Furthermore, initiator I is an azo initiator, and initiator II is an inorganic peroxide initiator.

[0009] Furthermore, the pollen is rapeseed pollen.

[0010] A method for preparing a thermosensitive photothermal pollen adsorbent, the method comprising the steps of:

[0011] S1, pollen is dispersed in a hydrochloric acid solution with a concentration of 1.5 mol / L to 3 mol / L, and stirred for 6 to 14 hours to form dispersion 1;

[0012] S2, the dispersion 1 is subjected to solid-liquid separation and washing to obtain pretreated pollen particles, and then the pretreated pollen particles are dispersed in an organic solvent to form dispersion 2.

[0013] S3, N-isopropylacrylamide and initiator I are dissolved in dispersion 2 and mixed to form a reaction solution. The graft polymerization reaction is carried out under nitrogen protection, stirring and constant temperature water bath conditions.

[0014] S4. After the graft polymerization reaction is completed, the reaction solution is filtered and washed, and then the obtained solid product is dispersed in an aqueous solution of pyrrole to form dispersion 3.

[0015] S5, Initiator II is dispersed in water to form dispersion 4;

[0016] S6, Lithium chloride is added to the acidic solution to form dispersion 5;

[0017] S7, Dispersion 3 and dispersion 4 are alternately dripped into dispersion 5, and the mixture is stirred and polymerized at a certain temperature for 6h to 14h.

[0018] S8. After filtering and washing the reaction product obtained in step S7, place it in a vacuum drying oven for drying to obtain a thermosensitive photothermal pollen adsorbent.

[0019] Furthermore, in step S1, the mass ratio of rapeseed pollen to hydrochloric acid solution in dispersion 1 is 1:80 to 1:150.

[0020] Furthermore, in step S3, the reaction solution is composed of the following components in mass percentage: 8%–15% N-isopropylacrylamide, 0.5%–1.5% initiator I, 3%–8% pretreated pollen grains, and the remainder is organic solvent. The graft polymerization reaction conditions are: constant temperature water bath temperature of 60℃–80℃, reaction time of 6h–8h, and nitrogen protection throughout the process.

[0021] Furthermore, the mass ratio of initiator II in step S5 to pyrrole in step S4 is 0.2:1 to 0.4:1.

[0022] Furthermore, in step S6, the acidic solution is a hydrochloric acid solution with a concentration of 1 mol / L to 2 mol / L, and the mass percentage of lithium chloride in the dispersion 5 is 5% to 40%.

[0023] Furthermore, in step S7, the polymerization reaction temperature is 15℃~35℃, and the polymerization reaction is stirred throughout.

[0024] Furthermore, in step S8, the drying temperature is 40℃~60℃, the vacuum degree is 0.3Mpa~0.7Mpa, and the drying time is 2h~6h.

[0025] The thermosensitive photothermal pollen adsorbent described in this application has high adsorption performance, low temperature desorption performance, good photo-thermal conversion and economy. When used for air water collection, it can significantly improve the working efficiency of air water collection systems and reduce working energy consumption and costs. Attached Figure Description

[0026] Figure 1 The results of the adsorption performance test of the adsorbent in Test Example 1 of this invention;

[0027] Figure 2 The results of the desorption performance test of the adsorbent in Test Example 2 of this invention;

[0028] Figure 3 Photograph of the sample used for testing the photo-thermal conversion capability as described in Test Example 3 of this invention;

[0029] Figure 4 This is a photograph of the sample during the light-to-heat conversion capability test process described in Test Example 3 of the present invention (illumination time 15 minutes);

[0030] Figure 5 The photograph shows the sample during the light-to-heat conversion capability test process described in Test Example 3 of this invention (illumination time 30 minutes);

[0031] Figure 6 The results are the light-to-heat conversion capacity test results of the thermosensitive photothermal pollen adsorbent described in Test Example 3 of the present invention. Detailed Implementation

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] A thermosensitive photothermal pollen adsorbent, wherein the raw materials for preparing the adsorbent include: pollen, N-isopropylacrylamide (NIPAM), pyrrole, lithium chloride, N-isopropylacrylamide polymerization initiator I and pyrrole polymerization initiator II, wherein the N-isopropylacrylamide is polymerized and grafted onto the pollen surface to form grafted pollen, and the pyrrole is polymerized and loaded onto the grafted pollen surface, that is, the grafted pollen is pollen particles with surface-grafted polyN-isopropylacrylamide, and the thermosensitive photothermal pollen adsorbent is grafted pollen with surface-polymerized polypyrrole.

[0034] Preferably, the thermosensitive photothermal pollen adsorbent is grafted pollen containing chlorinated polypyrrole and surface polymerized.

[0035] In the thermosensitive photothermal pollen adsorbent described in this application, the phase transition temperature of poly-N-isopropylacrylamide (PNIPAM) is 30-35°C. Therefore, by grafting poly-N-isopropylacrylamide (PNIPAM) onto the pollen surface, the adsorbent can be regenerated at low temperatures, such as at 40°C. At the same time, the chlorinated polypyrrole polymerized on the grafted pollen surface enables the adsorbent to possess both high adsorption capacity and excellent photothermal conversion ability. Furthermore, the pollen used in this application avoids the problem of liquid leakage and has the advantages of being naturally sourced and inexpensive.

[0036] Furthermore, initiator I is an azo initiator, and initiator II is an inorganic peroxide initiator.

[0037] As some embodiments of this application, the initiator I is one or more of azobisisobutyronitrile (AIBN), azobisisoheptanenitrile (ABVN), dimethyl azobisisobutyrate (AIBME), etc.

[0038] As some embodiments of this application, the initiator II is an inorganic persulfate, such as one or more of potassium persulfate, ammonium sulfate, etc.

[0039] Preferably, initiator I is azobisisobutyronitrile (AIBN), and initiator II is ammonium persulfate.

[0040] Furthermore, the pollen is rapeseed pollen, which is widely available, inexpensive, and readily available, thus improving the economic efficiency of the adsorbent described in this application and reducing the difficulty of its acquisition and preparation.

[0041] Furthermore, this application also provides a method for preparing a thermosensitive photothermal pollen adsorbent, the method comprising the steps of:

[0042] S1, pollen is dispersed in a hydrochloric acid solution with a concentration of 1.5 mol / L to 3 mol / L, and stirred for 6 to 14 hours to form dispersion 1;

[0043] S2, the dispersion 1 is subjected to solid-liquid separation and washing to obtain pretreated pollen particles, and then the pretreated pollen particles are dispersed in an organic solvent to form dispersion 2.

[0044] S3, N-isopropylacrylamide and initiator I are dissolved in dispersion 2 and mixed to form a reaction solution. The graft polymerization reaction is carried out under nitrogen protection, stirring and constant temperature water bath conditions.

[0045] S4. After the graft polymerization reaction is completed, the reaction solution is filtered and washed, and then the obtained solid product is dispersed in an aqueous solution of pyrrole to form dispersion 3.

[0046] S5, Initiator II is dispersed in water to form dispersion 4;

[0047] S6, Lithium chloride is added to the acidic solution to form dispersion 5;

[0048] S7, Dispersion 3 and dispersion 4 are alternately dripped into dispersion 5, and the mixture is stirred and polymerized at a certain temperature for 6h to 14h.

[0049] S8. After filtering and washing the reaction product obtained in step S7, place it in a vacuum drying oven for drying to obtain a thermosensitive photothermal pollen adsorbent.

[0050] Furthermore, in step S1, the mass ratio of pollen to hydrochloric acid solution in the dispersion 1 is 1:80 to 1:150.

[0051] In addition, it is important to note that the concentration of the hydrochloric acid solution must be strictly controlled within a specified range. If the concentration of the hydrochloric acid solution is too low, it will not be able to clean the impurities in the pollen, affecting the polymer-pollen composite and ultimately the performance of the adsorbent. If the concentration of the hydrochloric acid solution is too high, it will easily damage the pollen skeleton, affecting the pollen's loading on the polymer and the morphology of the adsorbent.

[0052] As some embodiments of this application, in step S1, the stirring time after dispersing pollen in hydrochloric acid solution can be adjusted according to the concentration of hydrochloric acid solution. Generally, the higher the concentration of hydrochloric acid solution, the shorter the stirring time.

[0053] As some embodiments of this application, in step S2, the organic solvent is one or more of methanol, ethanol, acetone, carbon tetrachloride, tetrahydrofuran, etc.

[0054] Preferably, in step S2, the organic solvent is anhydrous ethanol.

[0055] Furthermore, in step S3, the reaction solution is composed of the following components in mass percentage: 8%–15% N-isopropylacrylamide, 0.5%–1.5% initiator I, 3%–8% pretreated pollen grains, and the remainder is organic solvent. The graft polymerization reaction conditions are: constant temperature water bath temperature of 60℃–80℃, reaction time of 6h–8h, and nitrogen protection throughout the reaction.

[0056] As some embodiments of this application, in step S3, the reaction solution is composed of the following components by mass percentage: 8% N-isopropylacrylamide, 0.5% initiator I, 3% pretreated pollen grains, and the balance being an organic solvent. The graft polymerization reaction conditions are: constant temperature water bath temperature of 60°C, reaction time of 8 hours, and nitrogen protection throughout the reaction.

[0057] As some embodiments of this application, in step S3, the reaction solution is composed of the following components by mass percentage: 15% N-isopropylacrylamide, 1.5% initiator I, 8% pretreated pollen grains, and the balance being an organic solvent. The graft polymerization reaction conditions are: constant temperature water bath temperature of 80°C, reaction time of 7 hours, and nitrogen protection throughout the reaction.

[0058] As some embodiments of this application, in step S3, the reaction solution is composed of the following components by mass percentage: 12% N-isopropylacrylamide, 1% initiator I, 6% pretreated pollen grains, and the balance being an organic solvent. The graft polymerization reaction conditions are: constant temperature water bath temperature of 68°C, reaction time of 6.5 h, and nitrogen protection throughout the reaction.

[0059] Furthermore, in step S4, the volume percentage of pyrrole to water in the aqueous solution of pyrrole is 0.5 to 2:10.

[0060] Furthermore, in step S4, after the graft polymerization reaction is completed, the reaction solution is filtered and washed, and then the obtained solid product is dispersed in an aqueous solution of pyrrole to form a dispersion 3 with a solid product mass percentage of 30-70%.

[0061] Preferably, the mass ratio of initiator II in step S5 to pyrrole in step S4 is 0.2:1 to 0.4:1.

[0062] Preferably, in step S5, the mass percentage of initiator II in dispersion 4 is 1% to 2%.

[0063] Preferably, in step S5, deionized water is used to prepare the dispersion 4.

[0064] Furthermore, in step S6, the acidic solution is a hydrochloric acid solution with a concentration of 1 mol / L to 2 mol / L, and the mass percentage of lithium chloride in the dispersion 5 is 5% to 40%, such as 5%, 10%, 25%, 35%, and 40%.

[0065] Preferably, in step S6, the mass percentage of lithium chloride in the dispersion 5 is 10% to 30%. The saturated solubility of lithium chloride at room temperature is approximately 45 wt%. In this application, when the mass percentage of lithium chloride is 5% to 40%, the resulting adsorbent exhibits good hygroscopic properties. However, when the mass percentage of lithium chloride in the dispersion 5 exceeds 30%, the adsorbent easily absorbs excessive moisture, and occasionally, salt solution overflows.

[0066] Furthermore, the volume ratio of dispersion 5 to dispersion 4 is 3:1 to 5:1. In step S6, the amount of lithium chloride used will affect the performance of the adsorbent. Exceeding the given range of lithium chloride usage will cause the adsorbent to fail.

[0067] Furthermore, in step S7, dispersion 3 and dispersion 4 are alternately dripped into dispersion 5 within 1 to 3 hours, the polymerization reaction temperature is 15°C to 35°C, the polymerization reaction time is 6 hours to 14 hours, and the polymerization reaction is stirred throughout.

[0068] As some embodiments of this application, in step S7, the polymerization reaction temperature is 15°C, the polymerization reaction time is 14h, and the polymerization reaction is stirred throughout.

[0069] As some embodiments of this application, in step S7, the polymerization reaction temperature is 25°C, the polymerization reaction time is 8 hours, and the polymerization reaction is stirred throughout.

[0070] As some embodiments of this application, in step S7, the polymerization reaction temperature is 35°C, the polymerization reaction time is 6 hours, and the polymerization reaction is stirred throughout.

[0071] Furthermore, in step S8, the drying temperature is 40℃~60℃, the vacuum degree is 0.3Mpa~0.7Mpa, and the drying time is 2h~6h.

[0072] As some embodiments of this application, in step S8, the drying temperature is 50°C, the vacuum degree is 0.5 MPa, and the drying time is 4 hours.

[0073] As some embodiments of this application, in addition to being used for air-to-water extraction, the thermosensitive photothermal pollen adsorbent described in this application can also be used in the fields of moisture absorption and heat preservation, moisture absorption and heat storage, and moisture absorption and refrigeration.

[0074] The following specific examples illustrate the thermosensitive photothermal pollen adsorbent and its preparation method described in this application:

[0075] Example 1

[0076] (1) Disperse 3g of rapeseed pollen in 240g of 2mol / L hydrochloric acid and stir for 12h to form dispersion 1;

[0077] (2) Centrifuge and wash dispersion 1, and disperse the separated solids in 100 ml of anhydrous ethanol to form dispersion 2;

[0078] (3) Dissolve 0.075 mol (8.49 g) of N-isopropylacrylamide and 0.00475 mol (0.615 g) of azobisisobutyronitrile in dispersion 2 and mix them to form a reaction solution. Then react for 7 h under nitrogen protection, magnetic stirring and constant temperature water bath at 73 °C.

[0079] (4) After filtering and washing the reaction solution, disperse the solid product in 11 ml of pyrrole aqueous solution (pyrrole:deionized water volume ratio is 1:10) to form dispersion 3;

[0080] (5) Disperse 0.228g of ammonium persulfate into 20ml of deionized water to form dispersion 4;

[0081] (6) Add 10g of lithium chloride to 90ml of 1.5mol / L dilute hydrochloric acid to form dispersion 5;

[0082] (7) Dispersion 3 and dispersion 4 were alternately dripped into dispersion 5 over 1 hour to carry out the polymerization reaction. The polymerization reaction was carried out by stirring at room temperature (25°C) for 12 hours.

[0083] (8) After centrifuging, filtering and washing the reactants, place them in a vacuum drying oven and dry them at 50°C and 0.5 MPa for 4 hours to obtain the thermosensitive photothermal pollen adsorbent.

[0084] Example 2

[0085] (1) Disperse 6g of rapeseed pollen in 600g of 3mol / L hydrochloric acid and stir for 6h to form dispersion 1;

[0086] (2) Centrifuge and wash dispersion 1, and disperse the separated solids in 100 ml of anhydrous ethanol to form dispersion 2;

[0087] (3) Dissolve 0.115 mol (13 g) of N-isopropylacrylamide and 0.00512 mol (0.84 g) of azobisisobutyronitrile in dispersion 2 and mix them to form a reaction solution. Then react for 7 h under nitrogen protection, magnetic stirring and constant temperature water bath at 73 °C.

[0088] (4) After filtering and washing the reaction solution, disperse the solid product in 11 ml of pyrrole aqueous solution (pyrrole:deionized water volume ratio is 1:10) to form dispersion 3;

[0089] (5) Disperse 0.342g of ammonium persulfate into 20ml of deionized water to form dispersion 4;

[0090] (6) Add 20g of lithium chloride to 80ml of 1.5mol / L dilute hydrochloric acid to form dispersion 5;

[0091] (7) Dispersion 3 and dispersion 4 were alternately dripped into dispersion 5 over 2 hours to carry out the polymerization reaction. The polymerization reaction was carried out by stirring at room temperature (25°C) for 12 hours.

[0092] (8) After centrifuging, filtering and washing the reactants, place them in a vacuum drying oven and dry them at 55°C and 0.6 MPa for 3.5 h to obtain the thermosensitive photothermal pollen adsorbent.

[0093] Example 3

[0094] (1) Disperse 5g of rapeseed pollen in 750g of 2mol / L hydrochloric acid and stir for 8h to form dispersion 1;

[0095] (2) Centrifuge and wash dispersion 1, and disperse the separated solids in 100 ml of anhydrous ethanol to form dispersion 2;

[0096] (3) Dissolve 0.106 mol (12 g) of N-isopropylacrylamide and 0.00475 mol (0.78 g) of azobisisobutyronitrile in dispersion 2 and mix them to form a reaction solution. Then react for 7 h under nitrogen protection, magnetic stirring and constant temperature water bath at 73 °C.

[0097] (4) After filtering and washing the reaction solution, disperse the solid product in 11 ml of pyrrole aqueous solution (pyrrole:deionized water volume ratio is 1:10) to form dispersion 3;

[0098] (5) Disperse 0.248g of ammonium persulfate into 20ml of deionized water to form dispersion 4;

[0099] (6) Add 30g of lithium chloride to 70ml of 1.5mol / L dilute hydrochloric acid to form dispersion 5;

[0100] (7) Dispersion 3 and dispersion 4 were alternately dripped into dispersion 5 over 3 hours to carry out the polymerization reaction. The polymerization reaction was carried out by stirring at room temperature (25°C) for 12 hours.

[0101] (8) Centrifuge, filter and wash the reactants, and dry the final product in a vacuum drying oven at 60°C and 0.7 MPa for 4 hours to obtain the thermosensitive photothermal pollen adsorbent.

[0102] The performance of the adsorbents obtained in Examples 1-3 above was tested through experimental examples, as detailed below:

[0103] Among them, the adsorbent sample obtained in Example 1 is numbered Sample-10%wt, the adsorbent sample obtained in Example 2 is numbered Sample-20%wt, and the adsorbent sample obtained in Example 3 is numbered Sample-30%wt.

[0104] Experimental Example 1: Adsorption Performance Testing

[0105] The relative humidity and temperature conditions during the adsorption performance testing were precisely controlled by a constant temperature and humidity chamber. Before the adsorption experiment began, the adsorbent samples obtained in Examples 1-3, the commercially available lithium chloride-silica gel composite adsorbent, and the commercially available pure silica gel adsorbent were dried in an 80°C oven for 4 hours to obtain the mass of each sample before water absorption in the dry state. Afterwards, the dried samples were placed together in the constant temperature and humidity chamber for the adsorption performance testing. During the experiment, the adsorption temperature of the constant temperature and humidity chamber was set at 20°C, and the relative humidity was 70% RH. The adsorption lasted for 8 hours. The adsorbent samples obtained in Examples 1-3 and the commercially available lithium chloride-silica gel composite adsorbent were nearly saturated at 6 hours, and adsorption continued for 6 hours. The commercially available pure silica gel adsorbent adsorbed for 8 hours. During the adsorption process, the mass of each adsorbent after water absorption was weighed at certain time intervals using an electronic balance, and the amount of water vapor adsorbed by the adsorbent, i.e., the water absorption rate, was calculated. Water absorption rate = (m... 吸水后 -m 吸水前 ) / m 吸水前 ×100%, test results are shown in […]. Figure 1 .

[0106] Adsorption performance tests revealed that the average saturated water vapor adsorption capacity of the adsorbents in Examples 1-3 was 0.790 g / g, the saturated water vapor adsorption capacity of the silica-lithium chloride composite adsorbent was 0.368 g / g, and the saturated water vapor adsorption capacity of the pure silica adsorbent was 0.181 g / g. It can be seen that the adsorption performance of the adsorbent described in this application is improved by approximately 2 times and 4 times compared with the latter two, respectively.

[0107] Test Example 2: Desorption Performance Testing

[0108] The relative humidity and temperature conditions in the desorption performance test were precisely controlled by another constant temperature and humidity chamber, with the desorption conditions set at 40℃ and 10% RH. To ensure the accuracy of the test data, two constant temperature and humidity chambers were used in the test. Before starting the desorption performance test, the adsorbent samples obtained in Examples 1 and 2, the commercially available lithium chloride-silica gel composite adsorbent, and the commercially available pure silica gel adsorbent were placed in a constant temperature and humidity chamber at 20℃ and 70% RH for 6 hours for adsorption. The mass of each adsorbent sample after water absorption was weighed and used as the initial weight of each sample. Then, they were immediately placed in another constant temperature and humidity chamber that had been pre-set to the desorption conditions to begin the desorption performance test.

[0109] During the desorption performance test, the real-time mass of each adsorbent sample was weighed at certain time intervals using an electronic balance. The mass value obtained by subtracting the initial weight of each sample from the actual mass is the amount of water remaining in the adsorbent. The change in water absorption rate of each sample over time was then calculated. Figure 2 .

[0110] exist Figure 2 In the comparison of the experimental results obtained in Example 1 with those of commercially available silica-lithium chloride composite adsorbent and commercially available silica adsorbent, it can be found that the water content of Example 1, silica-lithium chloride composite adsorbent and pure silica adsorbent at the initial desorption time is 0.707 g / g, 0.279 g / g and 0.148 g / g, respectively. Under desorption conditions of 40℃ & 10%RH, after desorption for 0.5h and 1h, the residual water content in the adsorbent of the sample in Example 1 was 0.203g / g and 0.144g / g, respectively, accounting for 29% and 20% of the initial water content of desorption. At the corresponding desorption times, the residual water content of the silica-lithium chloride composite adsorbent was 0.187g / g and 0.157g / g, respectively, accounting for 67% and 56% of the initial water content of desorption. At the corresponding desorption times, the residual water content of the commercially available silica adsorbent was 0.042g / g and 0.025g / g, respectively, accounting for 28% and 17% of the initial water content of desorption.

[0111] Therefore, it can be seen that, within the same desorption time, the desorption rate and desorption amount of the adsorbent obtained in Example 1 are better than those of the silica-lithium chloride composite adsorbent and the pure silica adsorbent; although the desorption rate of the adsorbent in Example 1 is inferior to that of silica, its desorption amount is much greater than that of silica.

[0112] Test Example 3: Light-to-Heat Conversion Capability Test

[0113] The photo-thermal conversion capacity was measured by placing the sample material under sunlight. Specifically, the adsorbent sample obtained in Example 1 was first smoothly coated onto an aluminum sheet to obtain the sample (labeled AS). A photograph of the sample is shown below. Figure 3 The prepared sample was then placed in a constant temperature and humidity chamber at 20℃ and 85% RH for 6 hours for adsorption, and then placed under sunlight. The water vapor adsorption capacity of the adsorbent in the sample was weighed and calculated to be 1.251 g / g. After irradiation for 15 min and 30 min, the temperature of the aluminum sheet in the sample reached 60.2℃ and 62.8℃ respectively, as measured by infrared spectroscopy. (See details...) Figure 4 and Figure 5 .

[0114] During the photo-thermal conversion capability test, the remaining water content and aluminum sheet temperature of the sample were measured at certain time intervals after different illumination times, and the results were obtained. Figure 6 .according to Figure 6 It can be seen that after 5 hours of light exposure, the remaining water content of the sample can reach 0.093 g / g, indicating that the sample can achieve rapid desorption under light exposure.

[0115] In summary, the thermosensitive photothermal pollen adsorbent described in this application has the following characteristics:

[0116] First, the thermosensitive photothermal pollen adsorbent described in this application has excellent hygroscopic properties, which can be improved by 3 to 6 times and 2 to 4 times compared with silica gel adsorbent and silica gel-lithium chloride composite adsorbent, respectively.

[0117] Secondly, the thermosensitive photothermal pollen adsorbent described in this application can achieve low-temperature regeneration and can be fully desorbed within 40-50℃. It can utilize low-grade heat energy such as industrial waste heat to achieve desorption.

[0118] Third, the thermosensitive photothermal pollen adsorbent described in this application has excellent light-to-heat conversion capability. Under normal sunlight intensity, the temperature of the adsorbent itself can reach 50-70℃, thereby achieving solar regeneration.

[0119] Fourth, compared with other types of composite adsorbents, the thermosensitive photothermal pollen adsorbent described in this application uses ordinary rapeseed pollen as the material base, which is natural and inexpensive, making it more economical and environmentally friendly.

[0120] In summary, the thermosensitive photothermal pollen adsorbent described in this application has the advantages of high adsorption, low-temperature regeneration performance at 40-50℃, good photo-thermal conversion capability, and economy.

[0121] While the present invention has been disclosed above, it is not limited thereto. In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A thermosensitive photothermal pollen adsorbent, characterized in that, The raw materials for preparing the adsorbent include: pollen, N-isopropylacrylamide, pyrrole, lithium chloride, N-isopropylacrylamide polymerization initiator I and pyrrole polymerization initiator II. The N-isopropylacrylamide is polymerized and grafted onto the surface of the pollen to form grafted pollen, and the pyrrole is loaded onto the surface of the grafted pollen through a polymerization reaction. The preparation method of the thermosensitive photothermal pollen adsorbent includes the following steps: S1, pollen is dispersed in a hydrochloric acid solution with a concentration of 1.5 mol / L to 3 mol / L, and stirred for 6 to 14 hours to form dispersion 1; S2, the dispersion 1 is subjected to solid-liquid separation and washing to obtain pretreated pollen particles, and then the pretreated pollen particles are dispersed in an organic solvent to form dispersion 2. S3, N-isopropylacrylamide and initiator I are dissolved in dispersion 2 and mixed to form a reaction solution. The graft polymerization reaction is carried out under nitrogen protection, stirring and constant temperature water bath conditions. S4. After the graft polymerization reaction is completed, the reaction solution is filtered and washed, and then the obtained solid product is dispersed in an aqueous solution of pyrrole to form dispersion 3. S5, Initiator II is dispersed in water to form dispersion 4; S6, Lithium chloride is added to the acidic solution to form dispersion 5; S7, Dispersion 3 and dispersion 4 are alternately dripped into dispersion 5, and the mixture is stirred and polymerized at a certain temperature for 6h to 14h. S8. After filtering and washing the reaction product obtained in step S7, place it in a vacuum drying oven for drying to obtain a thermosensitive photothermal pollen adsorbent.

2. The thermosensitive photothermal pollen adsorbent according to claim 1, characterized in that, Initiator I is an azo initiator, and initiator II is an inorganic peroxide initiator.

3. The thermosensitive photothermal pollen adsorbent according to claim 1, characterized in that, The pollen in question is rapeseed pollen.

4. A method for preparing a thermosensitive photothermal pollen adsorbent, characterized in that, The preparation method is used to prepare the thermosensitive photothermal pollen adsorbent according to any one of claims 1 to 3. In step S1, the mass ratio of rapeseed pollen to hydrochloric acid solution in the dispersion 1 is 1:80 to 1:

150.

5. The preparation method of the thermosensitive photothermal pollen adsorbent according to claim 4, characterized in that, In step S3, the reaction solution consists of the following components by mass percentage: 8%–15% N-isopropylacrylamide, 0.5%–1.5% initiator I, 3%–8% pretreated pollen grains, and the remainder is organic solvent. The graft polymerization reaction conditions are: constant temperature water bath temperature of 60℃–80℃, reaction time of 6h–8h, and nitrogen protection throughout the process.

6. The preparation method of the thermosensitive photothermal pollen adsorbent according to claim 4, characterized in that, The mass ratio of initiator II in step S5 to pyrrole in step S4 is 0.2:1 to 0.4:

1.

7. The method for preparing the thermosensitive photothermal pollen adsorbent according to claim 4, characterized in that, In step S6, the acidic solution is a hydrochloric acid solution with a concentration of 1 mol / L to 2 mol / L, and the mass percentage of lithium chloride in the dispersion 5 is 5% to 40%.

8. The method for preparing the thermosensitive photothermal pollen adsorbent according to claim 4, characterized in that, In step S7, the polymerization reaction temperature is 15℃~35℃, and the polymerization reaction is stirred throughout.

9. The method for preparing the thermosensitive photothermal pollen adsorbent according to claim 4, characterized in that, In step S8, the drying temperature is 40℃~60℃, the vacuum degree is 0.3Mpa~0.7Mpa, and the drying time is 2h~6h.

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