CN113321231B - Method for preparing calcite by herbaceous plant induction - Google Patents

Abstract

The invention relates to a method for preparing calcite by inducing herbaceous plants, and belongs to the technical field of calcite synthesis. The method for preparing calcite by inducing herbaceous plants comprises the following steps: dispersing powder of herbaceous plants in water, reacting for 6-12 h at 200-220 ℃, and carrying out solid-liquid separation to obtain a carbon quantum dot solution, wherein the concentration of the carbon quantum dot solution is 20-25 g/L; mixing the carbon quantum dot solution and a soluble calcium salt solution to obtain a mixed solution, adding a soluble carbonate solution at a rate of 4-5 mL/min to react for 1.9-2.2 h, filtering, washing and drying to obtain calcite; wherein the herbaceous plant is at least one of alligator alternanthera or alligator alternanthera; the pH value of the carbon quantum dot solution is 6.9-10.35. According to the invention, the utilization value of the calcite is improved by using the invasive plants to prepare the calcite. The SEM picture of the calcite prepared by the method shows that the calcite has a flower-shaped structure with square petals and is high in purity.

Description

Method for preparing calcite by induction of herbs

technical field

The invention relates to a method for preparing calcite by induction of herbs, and belongs to the technical field of calcite synthesis.

Background technique

Calcite is a calcium carbonate mineral. Calcite has a variety of crystal shapes. You can get many square fragments by hitting calcite, hence the name Fangjie. The color of calcite varies depending on the impurities contained in it, such as light yellow, light red, brown-black, etc. when it contains iron and manganese, but generally it is mostly white or colorless. Colorless and transparent calcite is also called ice island stone. Such calcite has a wonderful feature, that is, through it, objects can be seen as double images. Therefore, iceland stone is an important optical material. Calcite has many uses in production and life. We know that limestone can form karst caves, and the stalactites and stalagmites in the caves are actually composed of calcite.

The main components of the travertine landscape also include calcite. Since groundwater contains high levels of HCO ₃ ^- , Ca ²⁺ and CO ₂ , when it is exposed to the surface, the partial pressure of CO ₂ in the environment suddenly decreases, resulting in CO ₂ in the water. Escape into the atmosphere, thereby forming _CaCO3 deposits, which are travertines. The landscape with calcareous as the main body is a treasure of nature and has huge humanistic value, scientific research value and economic value. The travertine scenic spots such as Jiuzhaigou and Huanglonggou attract a large number of tourists every year and become one of the local economic lifelines. However, the natural travertine landscape has degraded and damaged phenomena such as cracking, collapse, dissolution, and blackening. Min Shijie, Dang Zheng, Peng Qixuan, et al. Research on the preparation and application of travertine landscape restoration materials [J]. Nonmetallic Minerals, 2020(4): 4-7. The preparation method of travertine blocks using waste travertine as raw material is disclosed , after primary crushing of waste travertine to remove impurities, use jaw crusher and ball mill to crush and sieve it and save it, add a certain amount of travertine growth promoter and travertine enhancer in proportion to make a mixture, stir After homogenization, it was transferred to a mold, pressed and molded under a pressure of 30 MPa using a powder tablet machine, and then cured under CO ₂ conditions for 28 days for travertine landscape restoration. However, the preparation process is complicated, the cost is high, the preparation time is long, and the production efficiency is low.

In conclusion, it is very important to develop a new method for artificial preparation of calcite.

Zhang Daqin, Jia Zhigang, et al. Mineralization of polymorphic calcium carbonate particles induced by carbon quantum dots and its formation mechanism [J]. Chinese Journal of Inorganic Chemistry, 2020, 36(8): 1557-1566. A carbon quantum dot-induced polymorphic calcium carbonate particle is disclosed. The method for mineralization of calcium carbonate particles, the main steps of which are heat treatment with citric acid to prepare carbon quantum dots, and then induced to prepare calcium carbonate, but the cost of citric acid is high.

Invasive plants have a very strong growth ability, such as wildfires, which will overwhelm the original plants and destroy the diversity of the local ecosystem. After the successful invasion of most alien species, their growth is difficult to control. By suppressing or displacing native species, monodominant populations are formed, endangering the ecology of native species, and ultimately leading to the reduction of biodiversity. Invasive plants have low utilization value and are mainly removed by hand weeding or herbicides. Discarding the weeds after manual weeding is costly, and herbicides have a great impact on the environment. Therefore, improving its utilization value will not only help to reduce its harm to the environment, but also bring economic benefits.

At present, the composition of invasive plants is complex, and there is no technology that can use invasive plants to prepare pure calcite.

SUMMARY OF THE INVENTION

The first problem to be solved by the present invention is to provide a method for preparing calcite by induction of herbs.

In order to solve the first technical problem of the present invention, the method for preparing calcite by induction of the herb comprises:

a. Preparation of carbon quantum dots: Disperse the powder of herbs in water, react at 200-220 °C for 6-12 hours, and separate solid-liquid to obtain a carbon quantum dot solution, the concentration of which is 20-25 g/L;

b. Preparation of calcite: mix the carbon quantum dot solution with the soluble calcium salt solution to obtain a mixed solution, then add the soluble carbonate solution at a rate of 4 to 5 mL/min, react for 1.9 to 2.2 hours, filter and wash , drying to obtain calcite;

Wherein, the herbal plant is at least one of Radix japonica or Heliconia; the pH of the carbon quantum dot solution is 6.9-10.35.

The reaction temperature in step a will affect the reaction result, and the reaction temperature is preferably 200-220°C.

In a specific embodiment, the powder particle size of the herb is below 60 mesh; the preparation method of the herb powder is preferably drying the collected herb, washing with ethanol and deionized water, drying, grinding , sieved for use.

In a specific embodiment, according to step a, the powder of the herb is dispersed in water, and the reaction is carried out at 210° C. for 12 hours.

In a specific embodiment, the concentration of the carbon quantum dot solution is 22.5 g/L.

In a specific embodiment, the soluble calcium salt is at least one of CaCl ₂ , CaBr ₂ or Ca(NO ₃ ) ₂ , preferably CaCl ₂ ; the soluble carbonate Na ₂ CO At least one of ₃ or K ₂ CO ₃ , preferably Na ₂ CO ₃ .

In a specific embodiment, the concentration of the soluble calcium salt solution is 0.05-0.2 mol/L, preferably 0.1 mol/L; the concentration of the soluble carbonate solution is 0.05-0.2 mol/L L, preferably 0.1 mol/L.

In a specific embodiment, the volume ratio of the carbon quantum dot solution, the soluble calcium salt solution, and the soluble carbonate solution is: 6.75-81:10-40:10-40.

In a specific embodiment, the volume ratio of the carbon quantum dot solution, the soluble calcium salt solution, and the soluble carbonate solution is 9:20:20.

In a specific embodiment, the temperature of the reaction in step b is 25-29 °C, preferably 25 °C; the reaction time is preferably 2 h; preferably, the reaction in step b is also stirred at the same time, and the stirring The speed is 480～660r/min.

The second technical problem to be solved by the present invention is to provide a kind of calcite prepared by induction of herbs.

In order to solve the second technical problem of the present invention, the calcite prepared by the induction of herbs is prepared by the above-mentioned method for preparing calcite by induction of herbs, and the calcite is a flower pattern with a layered petal structure. Preferably, the petals are square.

Beneficial effects:

(1) Using the method of the present invention to prepare calcite with invasive plants can improve its utilization value.

(2) The SEM image of the calcite prepared by the method of the present invention shows that it has a flower-shaped structure with square petals, and the purity is high.

Description of drawings

The SEM image of Fig. 1 embodiment 1;

The SEM image of Fig. 2 embodiment 2;

The SEM image of Fig. 3 embodiment 4;

Figure 4 is the SEM image of Comparative Example 1;

Fig. 5 SEM image of comparative example 16;

Fig. 6 SEM image of comparative example 17;

Fig. 7 is the SEM image of comparative example 18;

Fig. 8 is the SEM image of comparative example 21;

The calcium carbonate product infrared image of Fig. 9 embodiment and part comparative example;

Fig. 10 is the TG test chart of the calcium carbonate product of embodiment 1, 4, comparative example 25 and travertine;

Fig. 11 is the calcium carbonate product XRD pattern of embodiment 1 and 2 and comparative examples 1-5;

Fig. 12 is the calcium carbonate product XRD figure of comparative example 6-9;

Fig. 13 is the calcium carbonate product XRD pattern of comparative example 10-13;

Fig. 14 is the calcium carbonate product XRD pattern of embodiment 3-7 and comparative example 22-25;

The calcium carbonate product XRD pattern of Fig. 15 embodiment 1 and comparative examples 18-21;

Fig. 16 is the calcium carbonate product XRD pattern of embodiment 1 and comparative examples 14-17;

FIG. 17 is a fluorescence image of the carbon quantum dots of the examples and some comparative examples under excitation at 455 nm.

Detailed ways

In order to solve the first technical problem of the present invention, the method for preparing calcite by induction of the herb comprises:

a. Preparation of carbon quantum dots: Disperse the powder of herbs in water, react at 200-220 °C for 6-12 hours, and separate solid-liquid to obtain a carbon quantum dot solution, the concentration of which is 20-25 g/L;

b. Preparation of calcite: mix the carbon quantum dot solution with the soluble calcium salt solution to obtain a mixed solution, then add the soluble carbonate solution at a rate of 4 to 5 mL/min, react for 1.9 to 2.2 hours, filter and wash , drying to obtain calcite;

Wherein, the herbal plant is at least one of Radix japonica or Heliconia; the pH of the carbon quantum dot solution is 6.9-10.35.

The reaction temperature in step a will affect the reaction result, and the reaction temperature is preferably 200-220°C.

In a specific embodiment, the powder particle size of the herb is below 60 mesh; the preparation method of the herb powder is preferably drying the collected herb, washing with ethanol and deionized water, drying, grinding , sieved for use.

In a specific embodiment, according to step a, the powder of the herb is dispersed in water, and the reaction is carried out at 210° C. for 12 hours.

In a specific embodiment, the concentration of the carbon quantum dot solution is 22.5 g/L.

In a specific embodiment, the soluble calcium salt is at least one of CaCl ₂ , CaBr ₂ or Ca(NO ₃ ) ₂ , preferably CaCl ₂ ; the soluble carbonate Na ₂ CO At least one of ₃ or K ₂ CO ₃ , preferably Na ₂ CO ₃ .

In a specific embodiment, the concentration of the soluble calcium salt solution is 0.05-0.2 mol/L, preferably 0.1 mol/L; the concentration of the soluble carbonate solution is 0.05-0.2 mol/L L, preferably 0.1 mol/L.

In a specific embodiment, the volume ratio of the carbon quantum dot solution, the soluble calcium salt solution, and the soluble carbonate solution is: 6.75-81:10-40:10-40.

In a specific embodiment, the volume ratio of the carbon quantum dot solution, the soluble calcium salt solution, and the soluble carbonate solution is 9:20:20.

In a specific embodiment, the temperature of the reaction in step b is 25-29 °C, preferably 25 °C; the reaction time is preferably 2 h; preferably, the reaction in step b is also stirred at the same time, and the stirring The speed is 480～660r/min.

In order to solve the second technical problem of the present invention, the calcite prepared by the induction of herbs is prepared by the above-mentioned method for preparing calcite by induction of herbs, and the calcite is a flower pattern with a layered petal structure. Preferably, the petals are square.

The specific embodiments of the present invention will be further described below with reference to the examples, but the present invention is not limited to the scope of the described examples.

Example 1

Cleaning of glass instruments such as reaction kettles and beakers: After preliminary brushing of the inner liner of the reaction kettle, etc. with a test tube brush, add ethanol to it, and ultrasonically clean it with an ultrasonic cleaner for 15 minutes. After taking it out, rinse it with deionized water, and dry it at 70 °C for later use. .

Preparation of carbon quantum dots: After drying the collected C. japonica, wash with ethanol and deionized water, and dry at 70°C. Grind the dried C. japonica with a mortar, pass through a 60-mesh sieve, and weigh. 0.9g of the hollow lotus seed grass powder passed through a 60-mesh sieve was placed in a beaker, 40mL of ultrapure water was added to it, stirred with a glass rod, and then dispersed by ultrasonic for 5min. , and after suction filtration, the obtained carbon quantum dot solution is sealed and stored. It was named CDs-0.9, and the pH was adjusted to 7.35 for use.

Preparation of calcium carbonate: prepare 20 mL of 0.1 mol/L CaCl ₂ and Na ₂ CO ₃ solutions in a beaker with deionized water, respectively, add 9 mL of CDs-0.9 solution to the CaCl ₂ solution, stir and mix well, and then use a constant Press the separatory funnel to add 20 mL of Na ₂ CO ₃ solution to the mixture at a rate of 4.2 mL/min, and stir at room temperature (25° C.) at 550 r/min for 2 h to complete the mineralization. After the reaction, the product was collected by filtration, washed several times with ultrapure water, and dried in an oven at 100°C. The prepared samples were stored and labeled in a sealed bag.

Example 2

The same as in Example 1, the only difference is that the herb is used as the herb.

Examples 3-7

Same as Example 1, the only difference is that the pH is adjusted to: 6.9, 8.35, 8.85, 9.85, 10.35, respectively.

Comparative Examples 1-13

Same as Example 1, the only difference is that the herbs are respectively water hyacinth, lantana, Echinacea, centipede grass, wood vinegar, corn stalk, rape stalk, wheat stalk, rice stalk, four kinds of humus: four kinds of humus. The humus was collected from four locations in Chengdu University of Technology. No. 1 was the mixed deciduous humus of Acacia japonica and T. cogongrass. Chicory mixed with humus. Wood vinegar liquid is a reddish-brown liquid obtained by condensation and separation of the steam-gas mixture derived from biomass such as wood after dry distillation in dry distillation equipment. The existing technology can be used to make or buy commercially available wood vinegar liquid. In this experiment, the commercially available wood vinegar liquid produced by Shandong Tairan New Energy Co., Ltd. was purchased.

Comparative Examples 14-17

The same as Example 1, the only difference is that 0g, 0.3g, 0.6g, 1.2g of Hollow lotus seed grass powder are weighed respectively.

Comparative Example 18-21

Same as Example 1, the only difference is that the mineralization was completed by moderate stirring at room temperature (25°C) for 0.5h, 1h, 4h and 6h respectively.

Comparative Example 22-25

Same as Example 1, the only difference is that the pH is adjusted to: 4.90, 5.35, 5.9, 6.35, respectively.

The carbon quantum dots prepared in Examples 1-7 and Comparative Examples 1-25, and the final calcium carbonate product were subjected to fluorescence detection, infrared detection, TG test, and SEM detection.

It can be seen from XRD diagrams 11-16 that the product prepared by the method of the present invention is calcite, and comparative examples 1-24 are mixtures of mixed calcite and vaterite.

It can be seen from SEM Figures 1-8 that the structures of the products prepared by some examples of the present invention are flower patterns with square petals, and the structures of the comparative examples are mixed.

It can be seen from the infrared image of Fig. 9 that the products prepared by the embodiment of the present invention have absorption peaks of calcite at 711cm ^-1 , 875cm ^-1 , 1420cm ^-1 , and other comparative examples have stronger absorption peaks at 1087cm- ¹ and 745cm ^-1 . The absorption peak, the sample has vaterite, and some comparative examples have absorption peak at 1455～1490cm ^-1 , the sample contains amorphous calcium carbonate.

TG test: TG test was carried out at 0~900°C (heating rate 20°C/min) under a _N2 atmosphere of 100mL/min. From the TG analysis, it can be seen that the temperature range of calcium carbonate decomposition into CaO and _CO2 ranges from 560 °C to 830 °C, and the temperature range of water evaporation in ACC particles is 35 °C to 330 °C. See Figure 10 for details.

It can be seen from Fig. 17 that the emission of carbon quantum dots of the plane grass and water hyacinth and the hollow lotus seed grass is similar. Other plants deviate greatly from the lotus seed grass.

Claims (19)

1. A method for preparing calcite by herbal induction, the method comprising:

a. preparing the carbon quantum dots: dispersing powder of herbaceous plants in water, reacting for 6-12 h at 200-220 ℃, and carrying out solid-liquid separation to obtain a carbon quantum dot solution, wherein the concentration of the carbon quantum dot solution is 20-25 g/L;

b. preparing calcite: mixing the carbon quantum dot solution and a soluble calcium salt solution to obtain a mixed solution, adding a soluble carbonate solution at a rate of 4-5 mL/min to react for 1.9-2.2 h, filtering, washing and drying to obtain calcite;

wherein the herbaceous plant is at least one of alligator alternanthera or aeroponicum praeparatum; the pH value of the carbon quantum dot solution is 6.9-10.35.

2. The method for the induced production of calcite according to claim 1, wherein the herbaceous plant has a powder size of 60 mesh or less.

3. The method for preparing calcite induced by herbs according to claim 2 wherein the powder of herbs is prepared by drying the collected herbs, washing with ethanol and deionized water, drying, grinding, and sieving.

4. The method for preparing calcite by induction from herbaceous plants as claimed in claim 1, wherein the powder of herbaceous plants is dispersed in water at 210 ℃ for 12h in step a.

5. The method for the induction preparation of calcite according to claim 1 or 2, characterized in that the concentration of the carbon quantum dots solution is 22.5 g/L.

6. The method for the induced production of calcite by herbaceous plants as claimed in claim 1 or 2, characterized in that the soluble calcium salt is CaCl ₂ 、CaBr ₂ Or Ca (NO) ₃ ) ₂ At least one of; the soluble carbonate Na ₂ CO ₃ Or K ₂ CO ₃ At least one of (1).

7. The method of induced preparation of calcite by herbaceous plants as claimed in claim 6, wherein the soluble calcium salt is CaCl ₂ 。

8. The method for the induced production of calcite by herbaceous plants as claimed in claim 6, characterized in that the soluble carbonate is Na ₂ CO ₃ 。

9. The method for the herbaceous plant induced preparation of calcite according to claim 1 or 2, wherein the concentration of the soluble calcium salt solution is 0.05-0.2 mol/L; the concentration of the soluble carbonate solution is 0.05-0.2 mol/L.

10. The method for the induced production of calcite according to claim 9, wherein the soluble calcium salt solution has a concentration of 0.1 mol/L.

11. The method for the induced production of calcite according to claim 9, characterized in that the concentration of the soluble carbonate solution is 0.1 mol/L.

12. The method for preparing calcite by induction from herbaceous plants according to claim 9, wherein the volume ratio of the carbon quantum dot solution, the soluble calcium salt solution and the soluble carbonate solution is as follows: 6.75-81: 10-40.

13. The method for the induced preparation of calcite according to claim 12, wherein the volume ratio of the carbon quantum dot solution, the soluble calcium salt solution and the soluble carbonate solution is 9:20: 20.

14. The method for preparing calcite by induction from herbaceous plants as claimed in claim 1 or 2, wherein the temperature of the reaction in step b is 25-29 ℃.

15. The process for the induced preparation of calcite according to claim 14, wherein the temperature of the reaction in step b is 25 ℃.

16. The process for the induced production of calcite according to claim 14, characterized in that the reaction time in step b is 2 h.

17. The method for preparing calcite by induction from herbaceous plants as claimed in claim 14, wherein the reaction in step b is carried out with stirring at 480-660 r/min.

18. Herbal plant-induced calcite, which is prepared by the method for preparing calcite through herbal plant induction according to any one of claims 1-17, wherein the calcite is flower-shaped with a layered petal structure.

19. Calcite produced by induction from an herbaceous plant as claimed in claim 18, wherein said petals are square.

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