Preparation method of color-changing calcium carbonate adsorption drying agent

Abstract

The invention provides a preparation method of a color-changing calcium carbonate adsorption drying agent, which comprises the following steps: preparing porous calcium carbonate by using artificial agglomerated stone waste residue as a raw material through high-temperature calcination by a salting-out method, coupling by using an aluminum-titanium composite coupling agent, and preparing the color-changing calcium carbonate adsorption drying agent by using cobalt chloride as a coloring agent. The average pore size of the prepared color-changing calcium carbonate adsorption drying agent is about 38nm, the color-changing calcium carbonate adsorption drying agent is of a mesoporous structure, the saturated water absorption capacity in air can reach 45.625 mg / g, and the color is changed from blue to light red after water absorption. After being dried, the product turns from light red to blue and can be repeatedly used.

Description

Technical Field

[0001] The invention relates to the technical field of porous materials, and in particular to a method for preparing a color-changing calcium carbonate adsorption desiccant for adsorbing moisture. Background Art

[0002] With the rapid development of science and technology, humans have been able to express and apply colors in many ways. Among them, the development and application of color-changing materials have brought us a refreshing "colorful" life. At present, the research on color-changing materials at home and abroad has become increasingly mature, involving various fields such as silica gel desiccant in clothes, color-changing glasses worn daily, color-changing lipstick, color-changing water cups, etc., to meet people's pursuit of beauty. The methods for preparing color-changing materials include dyeing, photochromic method, thermochromic method, and thermochromic method. Hezhou, Guangxi has the reputation of "the capital of granite" and "the capital of heavy calcium", but the waste residue generated in the production process of artificial granite contains solidified unsaturated resin and cannot be comprehensively utilized. The treatment methods are mostly open-air stacking and simple landfill, which not only wastes resources, but also causes environmental pollution. According to the composition of artificial granite waste residue, artificial granite waste residue can be used to prepare porous calcium carbonate, calcium formate, nano calcium carbonate, building composite materials and other products.

[0003] The present invention adopts artificial granite waste as raw material, prepares porous calcium carbonate by high temperature calcination through salting out method, couples with aluminum titanium composite coupling agent, and uses cobalt chloride as dyeing agent to prepare color-changing calcium carbonate adsorption desiccant. After literature search, no report on preparing color-changing calcium carbonate adsorption desiccant using artificial granite waste as raw material was found. Summary of the invention

[0004] In order to overcome the problem of recycling artificial granite waste residue, a method for preparing a color-changing calcium carbonate adsorption desiccant is provided. Artificial granite waste residue is used as a raw material, porous calcium carbonate is prepared by high-temperature calcination by a salting-out method, an aluminum-titanium composite coupling agent is used for coupling, and cobalt chloride is used as a dye to prepare a color-changing calcium carbonate adsorption desiccant. The present invention solves the technical problem by adopting the following technical solutions:

[0005] A method for preparing a color-changing calcium carbonate adsorption desiccant, characterized in that the method comprises the following steps:

[0006] a. Weigh 10g of artificial granite waste slag through a 100-mesh sieve, add 100mL 15wt% sodium chloride solution, stir and react for 4h, filter, dry, pre-calcine in a universal furnace for 0.5h, and calcine in a muffle furnace to obtain porous calcium carbonate, wherein the calcination time is 135min, the calcination temperature is 700℃, and the holding time is 3.5h;

[0007] b. CoCl 4 6H 2O is a dye, coupled with an aluminum-titanium composite coupling agent, the porous calcium carbonate prepared in step a and the aluminum-titanium composite coupling agent are placed in a three-necked flask, 2-5wt% cobalt chloride solution is added according to a solid-liquid ratio of 1:10, stirred at a temperature of 30-60°C for 1-2h, filtered and dried to obtain a color-changing calcium carbonate adsorption desiccant.

[0008] The pH value of the cobalt chloride solution is 5.5-7.5.

[0009] The dosage of the aluminum-titanium composite coupling agent is 1.1wt% of the porous calcium carbonate.

[0010] The color-changing calcium carbonate adsorption desiccant is used in a drying process for adsorbing moisture.

[0011] The beneficial effects of the present invention are:

[0012] 1. Comprehensive utilization of artificial granite waste to solve environmental problems;

[0013] 2. The average pore size of the prepared color-changing calcium carbonate adsorption desiccant is about 38nm, and it has a mesoporous structure. The saturated water absorption capacity in the air can reach 45.625mg / g. After absorbing water, the color changes from blue to light red, and the color change is obvious.

[0014] 3. The color-changing calcium carbonate adsorption desiccant changes from light red to blue after drying and can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the pore volume-pore size distribution curve of the porous calcium carbonate prepared in Example 4.

[0016] Figure 2 This is the infrared spectra of the color-changing calcium carbonate adsorption desiccant and artificial granite waste slag prepared in Example 4.

[0017] Figure 3 This is a scanning electron microscope image of artificial granite waste.

[0018] Figure 4 This is a scanning electron microscope image of porous calcium carbonate.

[0019] Figure 5 This is a scanning electron microscope image of the color-changing calcium carbonate adsorption desiccant of Example 4.

[0020] Figure 6 This is the saturated adsorption curve of the color-changing calcium carbonate adsorption desiccant prepared in Example 4 when adsorbing moisture in the air. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are further described in detail below: It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, and therefore the present invention is not limited to the embodiments described in the specific implementation manners, and any other implementation manners derived from the technical solutions of the present invention by those skilled in the art also fall within the scope of protection of the present invention.

[0022] The yellow-blue value determination process of the color-changing calcium carbonate adsorption desiccant is as follows:

[0023] The color-changing calcium carbonate adsorption desiccant sample was pressed into a sheet, and the L, a, and b values ​​were measured under the illumination of a light source with a spectral range of 400nm to 700nm under the optical geometry conditions of a colorimeter of 45 / 0 or 0 / 45. The test was repeated three times, and the average value of the b value was taken as the single test result. The b value is the yellow-blue value, which indicates that CoCl 4 The smaller the b value, the bluer it appears. 4 The more it enters the porous calcium carbonate.

[0024] Example 1

[0025] a. Weigh 10g of artificial granite waste slag through a 100-mesh sieve, add 100mL 15wt% sodium chloride solution, stir and react for 4h, filter, dry, pre-calcine in a universal furnace for 0.5h, and calcine in a muffle furnace to obtain porous calcium carbonate, wherein the calcination time is 135min, the calcination temperature is 700℃, and the holding time is 3.5h;

[0026] b. CoCl 4 6H 2 O is a dye, coupled with an aluminum-titanium composite coupling agent, the porous calcium carbonate prepared in step a and the aluminum-titanium composite coupling agent are placed in a three-necked flask, 3 wt% cobalt chloride solution is added according to a solid-liquid ratio of 1:10, stirred at 60° C. for 2 h, and a color-changing calcium carbonate adsorption desiccant is obtained after filtering and drying.

[0027] The pH value of the cobalt chloride solution is 6.5.

[0028] The dosage of the aluminum-titanium composite coupling agent is 1.1wt% of the porous calcium carbonate.

[0029] The yellow-blue value of the prepared color-changing calcium carbonate adsorption desiccant is 7. After absorbing water, the color changes from blue to pinkish red, and after drying, it changes from light red to blue.

[0030] Example 2

[0031] a. Weigh 10g of artificial granite waste slag through a 100-mesh sieve, add 100mL 15wt% sodium chloride solution, stir and react for 4h, filter, dry, pre-calcine in a universal furnace for 0.5h, and calcine in a muffle furnace to obtain porous calcium carbonate, wherein the calcination time is 135min, the calcination temperature is 700℃, and the holding time is 3.5h;

[0032] b. CoCl 4 6H 2 O is a dye, coupled with an aluminum-titanium composite coupling agent, the porous calcium carbonate prepared in step a and the aluminum-titanium composite coupling agent are placed in a three-necked flask, 4 wt% cobalt chloride solution is added according to a solid-liquid ratio of 1:10, stirred at 30° C. for 1.5 h, and a color-changing calcium carbonate adsorption desiccant is obtained after filtering and drying.

[0033] The pH value of the cobalt chloride solution is 6.5.

[0034] The dosage of the aluminum-titanium composite coupling agent is 1.1wt% of the porous calcium carbonate.

[0035] The yellow-blue value of the prepared color-changing calcium carbonate adsorption desiccant is 3. After absorbing water, the color changes from blue to pinkish red, and after drying, it changes from light red to blue.

[0036] Example 3

[0037] a. Weigh 10g of artificial granite waste slag through a 100-mesh sieve, add 100mL 15wt% sodium chloride solution, stir and react for 4h, filter, dry, pre-calcine in a universal furnace for 0.5h, and calcine in a muffle furnace to obtain porous calcium carbonate, wherein the calcination time is 135min, the calcination temperature is 700℃, and the holding time is 3.5h;

[0038] b. CoCl 4 6H 2 O is a dye, coupled with an aluminum-titanium composite coupling agent, the porous calcium carbonate prepared in step a and the aluminum-titanium composite coupling agent are placed in a three-necked flask, 3 wt% cobalt chloride solution is added according to a solid-liquid ratio of 1:10, stirred at 30° C. for 1.5 h, filtered and dried to obtain a color-changing calcium carbonate adsorption desiccant.

[0039] The pH value of the cobalt chloride solution is 7.5.

[0040] The dosage of the aluminum-titanium composite coupling agent is 1.1wt% of the porous calcium carbonate.

[0041] The yellow-blue value of the prepared color-changing calcium carbonate adsorption desiccant is 5. After absorbing water, the color changes from blue to pinkish red, and after drying, it changes from pinkish red to blue.

[0042] Example 4

[0043] a. Weigh 10g of artificial granite waste slag through a 100-mesh sieve, add 100mL 15wt% sodium chloride solution, stir and react for 4h, filter, dry, pre-calcine in a universal furnace for 0.5h, and calcine in a muffle furnace to obtain porous calcium carbonate, wherein the calcination time is 135min, the calcination temperature is 700℃, and the holding time is 3.5h;

[0044] b. CoCl 4 6H 2 O is a dye, coupled with an aluminum-titanium composite coupling agent, the porous calcium carbonate prepared in step a and the aluminum-titanium composite coupling agent are placed in a three-necked flask, 3 wt% cobalt chloride solution is added according to a solid-liquid ratio of 1:10, stirred at 30° C. for 1.5 h, filtered and dried to obtain a color-changing calcium carbonate adsorption desiccant.

[0045] The pH value of the cobalt chloride solution is 6.5.

[0046] The dosage of the aluminum-titanium composite coupling agent is 1.1wt% of the porous calcium carbonate.

[0047] The yellow-blue value of the prepared color-changing calcium carbonate adsorption desiccant is 1. After absorbing water, the color changes from blue to pinkish red, and after drying, it changes from light red to blue.

[0048] Figure 1 The pore volume-pore size distribution curve of the porous calcium carbonate prepared in Example 4 shows that the pore size ranges from 2 nm to 300 nm, with a wide distribution and an average adsorption pore size of 38.719 nm. The reason for this is that the unsaturated resin in the artificial granite waste slag volatilizes after high-temperature calcination, forming pores in the sample; and sodium chloride, as a pore-forming agent, causes a pore explosion, resulting in a surface depression to form holes.

[0049] Figure 2 This is the infrared spectrum of the color-changing calcium carbonate adsorption desiccant prepared in Example 4 and the artificial granite waste residue. It can be seen from the figure that the two have overlapping characteristic absorption peaks. The wave number is 1790cm -1 、1386cm -1 、878cm -1 、711cm -1 There is stretching vibration of CO bond, which is CO3 2- The characteristic absorption peak is obvious, which can be used to determine that artificial granite waste and discolored calcium carbonate adsorbent contain CO3 2- The product is mainly calcium carbonate, and the crystal form of calcium carbonate is calcite. The wave number of the test data is 1712cm -1 The position is the double bond in the unsaturated resin of artificial granite waste slag, while the color-changing calcium carbonate adsorption desiccant does not have this peak. Analysis shows that the unsaturated resin in the artificial granite waste slag has been volatilized during the high-temperature calcination in the muffle furnace, so there is no organic matter in the composition of the color-changing calcium carbonate adsorbent.

[0050] Figure 3 This is a scanning electron microscope image of artificial granite waste. Figure 4 This is a scanning electron microscope image of porous calcium carbonate. Figure 5 This is a scanning electron microscope image of the color-changing calcium carbonate adsorption desiccant of Example 4. Figure 3 It can be analyzed that the surface of artificial granite waste is smooth but not flat, with obvious agglomeration, tight and irregular structure, clear and smooth lines, and uneven surface. The reason for this phenomenon is that in addition to calcium carbonate, artificial granite waste also contains some unsaturated resin and impurities. Figure 4 It can be seen that the surface of porous calcium carbonate has uneven holes, and the surface becomes rough and uneven due to the holes. The main reason is that the unsaturated resin in the artificial granite waste has been volatilized during the high-temperature calcination in the muffle furnace. Due to the explosion of sodium chloride molecules, pores appear between calcium carbonate molecules; therefore, there are uneven holes on the surface, and the size of the pores is inconsistent, leaving holes and depressions on the surface of the calcium carbonate molecules, resulting in an uneven molecular surface; Figure 5 There are still many concave holes on the molecular surface of the medium-color calcium carbonate adsorption desiccant and the molecular surface is not smooth. The reason is that cobalt chloride and calcium carbonate do not react. Cobalt ions mainly exist in the pores and some are also on the surface of calcium carbonate. Since the diameter of cobalt ions is small and the pore size of calcium carbonate is large, the color-changing calcium carbonate adsorbent still has a large number of holes.

[0051] Figure 6 The saturated adsorption curve of the color-changing calcium carbonate adsorption desiccant prepared in Example 4 adsorbs moisture in the air. As can be seen from the figure, as time increases, the longer the adsorption time of the color-changing calcium carbonate adsorption desiccant is, the more moisture it adsorbs, and the color gradually changes from blue to light red until it is no longer adsorbed. The adsorbed moisture changes slowly in the first three days, and the adsorption capacity shows a sharp rise on the fourth day. The adsorption capacity is still rising slowly in the following days. After nine days of adsorption, the adsorption capacity shows a downward trend. The reason for this is that the longer the adsorption time is, the more moisture is adsorbed. When the porous pore capacity reaches saturation, the saturated adsorption capacity is 45.625 mg / g, and then it is difficult to adsorb moisture in the air, and the adsorption capacity begins to decline. The color-changing calcium carbonate adsorption desiccant gradually loses its adsorption effect and needs to be dried again for continued use.

Claims

1. A method for preparing a color-changing calcium carbonate adsorption desiccant, characterized in that: The method comprises the following steps: a. Weigh 10g of artificial granite waste slag through a 100-mesh sieve, add 100mL 15wt% sodium chloride solution, stir and react for 4h, filter, dry, pre-calcine in a universal furnace for 0.5h, and calcine in a muffle furnace to obtain porous calcium carbonate, wherein the calcination time is 135min, the calcination temperature is 700℃, and the holding time is 3.5h; b. Use CoCl4·6H2O as dyeing agent and aluminum-titanium composite coupling agent for coupling. Put the porous calcium carbonate and aluminum-titanium composite coupling agent prepared in step a into a three-necked flask, add 2-5wt% cobalt chloride solution at a solid-liquid ratio of 1:10, stir at 30-60℃ for 1-2h, filter and dry to obtain color-changing calcium carbonate adsorption desiccant.

2. The method for preparing a color-changing calcium carbonate adsorption desiccant according to claim 1, characterized in that: The pH value of the cobalt chloride solution described in step b is 5.5-7.

5.

3. The method for preparing a color-changing calcium carbonate adsorption desiccant according to claim 1, characterized in that: The amount of the aluminum-titanium composite coupling agent in step b is 1.1 wt % of the porous calcium carbonate.

4. The method for preparing a color-changing calcium carbonate adsorption desiccant according to claim 1, characterized in that: The color-changing calcium carbonate adsorption desiccant described in step b is used in the drying process of absorbing moisture. After absorbing water, the color changes from blue to pinkish red, and after drying, the color changes from pinkish red to blue.

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