CN107936197A - A kind of humic acid composite gel material and preparation method - Google Patents

Abstract

The invention discloses a humic acid composite gel material and a preparation method thereof, which belong to a polymer gel material and a preparation method thereof. The humic acid composite gel material takes the ratio of raw materials as the mass ratio, based on 100 parts of deionized water, and other raw materials include: 2.5-20 parts of sodium humate, 8-20 parts of acrylamide, 2-8 parts of sodium carboxymethyl starch 0.5-1.26 parts of sodium hydroxide, 1-5 parts of N,N'-methylenebisacrylamide, and 0.5-3 parts of ammonium persulfate. Method: Dissolve sodium humate in deionized water first to make sodium humate solution, then add acrylamide, sodium carboxymethyl starch, ammonium persulfate, N,N'-methylenebisacrylamide and NaOH solution to Sodium humate solution; Stirring, mixing, heating, gelation, drying to obtain xerogel. Advantages: The preparation process of the composite gel is relatively simple, the wet gel has better elasticity; the thermal stability is good; the composite gel has good strength, not only has a large number of microporous structures, but also has a fibrous structure interspersed with each other, and the gel structure is more stable.

Description

A kind of humic acid composite gel material and preparation method thereof

technical field

The invention relates to a polymer gel material and a preparation method, in particular to a humic acid composite gel material and a preparation method.

Background technique

China is rich in humic acid resources, with large reserves and wide distribution. It can be widely used in various fields such as agriculture, forestry, animal husbandry, petroleum, chemical industry, building materials, medicine, health, and environmental protection, such as fertilizers, pesticides, veterinary drugs, drought-resistant agents, and feed additives. ; Medicines, health care products, cosmetics; Petroleum additives, industrial water treatment agents, coal water slurry stabilizers, battery expansion agents, ceramic additives, ink additives, etc. However, because humic acid has no stable chemical composition, this leads to unstable properties of humic acid when used. With the industrial upgrading of various industries, the requirements for the stability of the production process are getting higher and higher, the application of humic acid products in industry is gradually decreasing, and the large-scale use of humic acid is mainly used as agricultural organic fertilizer at present. However, the added value of agricultural organic fertilizer is not high, and it is urgent to develop a new technology to expand the application field and improve the utilization value.

On the other hand, the research and development of new technologies for humic acid products is also changing with each passing day. A number of new humic acid utilization technologies have been announced one after another, mainly including new functional fertilizers, such as CN106032341A; fluoride ion adsorbents, such as CN104096547A; humic acid microspheres, such as CN105854828A can be used to remove cationic dyes in wastewater; superabsorbent resins, such as CN101538340A, adopt microwave polymerization method, and the residual amount of resin monomers prepared is low; and numerous water-retaining agent preparation methods, such as CN1687193A, CN1912006A, CN105176536A, CN105482048A, etc. These utilization methods mainly utilize the porosity of humic acid, which is a better adsorption and ion exchange material.

In recent years, hydrogel has developed rapidly due to its high water absorption and high water retention properties. The preparation of humic acid into hydrogel will greatly improve its adsorption performance. The research on the preparation of humic acid into hydrogel has great application prospects. The hydrogel announced by patent CN105754050A uses acrylic acid and humic acid as the main raw materials, and the product has high water absorption rate, good salt resistance and gel strength. The hydrogel disclosed in patent CN106732423A is prepared from hydroxyethyl cellulose, attapulgite, and sodium humate through a free radical method. The composite hydrogel has good swelling performance, has a porous three-dimensional network structure, and has a good Thermal stability, salt resistance and wide pH range, good adsorption effect on methylene blue dye. The hydrogel published in the patent CN105949407A is made of sodium humate and acrylamide as raw materials, through the action of crosslinking agent and initiator, and polymerized at 40-90°C. It has good temperature resistance and salt resistance, and has no pollution to the environment. .

Comparing patents CN105754050A, CN106732423A, and CN105949407A, it can be found that humic acid can be compounded with different compounds to prepare hydrogels, but in terms of the preparation process and hydrogel characteristics mentioned in the above three patents, there are mainly the following two problems : 1. The addition of humic acid is less. For example, patent CN105754050A mentions 55 to 91 parts of acrylic acid and 9 to 45 parts of humate, while in patent CN106732423A, the mass ratio of hydroxyethyl cellulose: acrylic acid: attapulgite: sodium humate is 1:4～ 10:0.2～4:0.2～2. In patent CN105949407A, the mass ratio of acrylamide monomer to sodium humate monomer is 20:1-200:1, and the amount of humic acid added is 5‰ to 5%. 2. The reaction preparation conditions are harsh. For example, the patent CN106732423A needs to be carried out under inert atmospheres such as nitrogen and argon.

Contents of the invention

The purpose of the present invention is to provide a humic acid composite gel material and its preparation method to solve the problem of too little amount of humic acid in the current humic acid preparation hydrogel technology, while not reducing the water absorption performance and physical and chemical stability.

The purpose of the present invention is achieved in this way, the technical scheme of the present invention comprises: humic acid composite gel material and the preparation method of humic acid composite gel material.

The humic acid composite gel material includes: sodium humate, acrylamide, sodium carboxymethyl starch, ammonium persulfate, N,N'-methylenebisacrylamide and NaOH solution; the raw material ratio is a mass ratio, with Based on 100 parts of deionized water, other raw materials include: 2.5-20 parts of sodium humate, 8-20 parts of acrylamide, 2-8 parts of sodium carboxymethyl starch, 0.5-1.26 parts of sodium hydroxide, N, N'— 1-5 parts of methylenebisacrylamide, 0.5-3 parts of ammonium persulfate.

The preparation method of composite gel material comprises the following steps:

a. Add sodium humate into the deionized water container at an ambient temperature of 20°C±3, and after ultrasonic vibration, the sodium humate is fully dissolved in the deionized water, and the sodium humate solution is filtered with rapid qualitative filter paper, and the sodium humate solution will not The sodium humate component dissolved in deionized water is filtered out to prepare a sodium humate solution;

b. Then add acrylamide, sodium carboxymethyl starch, N,N'-methylenebisacrylamide and ammonium persulfate to the sodium humate solution in sequence, and finally add 1.7 to 4.3 parts of pre-prepared NaOH solution, The pre-prepared NaOH solution adopts analytically pure 5.000g NaOH and deionized water to configure a sodium hydroxide standard solution with a mass fraction of 29.385%;

c. Stir at a constant temperature of 25°C for 15 minutes to fully mix the ingredients, then transfer the mixture into a washed and dried test tube, and seal it with plastic wrap;

d. Place the test tube in a heating device, raise the temperature to 60°C, and keep the temperature at 60°C for 1-5 hours; through inversion of the test tube, the condition of no obvious flow of the mixed system is used to determine the formation of the gel;

e. Take out the gel, and dry it in a blast drying oven at 60° C. to a constant weight to obtain a xerogel.

Beneficial effects, due to the adoption of the above scheme, the formula adopted in this method aims at the maximum theoretical number of hydrogen bonds, and the preparation process does not require an inert atmosphere. After the wet gel is successfully prepared, it is pressed with a glass rod, and the elasticity is very good. The humic acid composite gel shows that the composite gel has a rich microporous structure and interpenetrating fibrous structure. The gel does not decompose until 220 ° C, and the content of humic acid is increased to more than 10%, which solves the current problem of humic acid preparation. The problem of using too little humic acid in the gel technology,.

The advantages of the present invention are: the preparation process of the composite gel is relatively simple, the wet gel has better elasticity; the thermal stability is good; The structure is more stable;

1. my country’s lignite and weathered coal used to extract humic acid have huge reserves and low prices, but most of them are used for combustion to generate electricity, with low utilization value, waste of resources and easy to cause environmental pollution; use lignite or weathered coal humate Prepare composite gel materials, open up the utilization of lignite and weathered coal, and improve the utilization value.

2. The present invention uses sodium humate, acrylamide and sodium carboxymethyl starch as raw materials to prepare a new composite hydrogel, which has a network structure with abundant microporous structures interspersed with each other.

3. The amount of humic acid used in the preparation of humic acid series hydrogels is increased, and the utilization rate of sodium humate is improved.

Description of drawings

Figure 1 is a scanning electron microscope image of a humic acid composite gel.

Figure 2 is the DSC-TGA curve of the humic acid composite gel.

Fig. 3 is the infrared spectrogram of humic acid composite gel.

Detailed ways

The technical scheme of the invention includes: a humic acid composite gel material and a preparation method of the humic acid composite gel material.

The humic acid composite gel material includes: sodium humate, acrylamide, sodium carboxymethyl starch, ammonium persulfate, N,N'-methylenebisacrylamide and NaOH solution; the raw material ratio is a mass ratio, with Based on 100 parts of deionized water, other raw materials include: 2.5-20 parts of sodium humate, 8-20 parts of acrylamide, 2-8 parts of sodium carboxymethyl starch, 0.5-1.26 parts of sodium hydroxide, N, N'— 1-5 parts of methylenebisacrylamide, 0.5-3 parts of ammonium persulfate.

The preparation method of composite gel material comprises the following steps:

a. Add sodium humate into the deionized water container at an ambient temperature of 20°C±3, and after ultrasonic vibration, the sodium humate is fully dissolved in the deionized water, and the sodium humate solution is filtered with rapid qualitative filter paper, and the sodium humate solution will not The sodium humate component dissolved in deionized water is filtered out to prepare a sodium humate solution;

b. Then add acrylamide, sodium carboxymethyl starch, N,N'-methylenebisacrylamide and ammonium persulfate to the sodium humate solution in sequence, and finally add 1.7 to 4.3 parts of pre-prepared NaOH solution, The pre-prepared NaOH solution adopts analytically pure 5.000g NaOH and deionized water to configure a sodium hydroxide standard solution with a mass fraction of 29.385%;

c. Stir at a constant temperature of 25°C for 15 minutes to fully mix the ingredients, then transfer the mixture into a washed and dried test tube, and seal it with plastic wrap;

d. Place the test tube in the heating equipment, naturally raise the temperature to 60°C, and keep the temperature at 60°C for 1-5h; through inversion of the test tube, the condition of no obvious flow of the mixed system is used to determine the formation of the gel;

e. Take out the gel, and dry it in a blast drying oven at 60° C. to a constant weight to obtain a xerogel.

Figure 1 is a scanning electron microscope image of a humic acid composite gel.

It can be seen from the figure that a, b, c and d are 2000, 1500, 2000 and 1500 times scanning electron micrographs of the gel taken at 25kV, respectively. a and b are taken from the section of the gel, and c and d are taken from the surface of the gel. The composite hydrogel has abundant microporous structure and interpenetrating fibrous structure.

Figure 2 is the DSC-TGA curve of the humic acid composite gel.

It can be seen from the figure that the gel heating process is roughly divided into three stages. In the first stage, unbound moisture (adsorbed moisture and moisture in pores) and some bound moisture are removed; in the second stage, small molecular substances and some volatiles are removed; in the third stage, melting phase transition. The thermal stability of the gel is good, when the temperature is higher than 220 ° C, some substances will be degraded, and the temperature will start to melt when the temperature is above 450 ° C.

Fig. 3 is the infrared spectrogram of humic acid composite gel.

a-sodium carboxymethyl starch; b-acrylamide; c-sodium humate; d-gel;

It can be seen from the figure that the 3441cm ^-1 peak in d indicates that the gel has hydrogen bonds, and the absorption peak intensity at 2918cm ^-1 and 2849cm ^-1 is stronger than that of a-carboxymethyl starch sodium, b-acrylamide and c-sodium humate , indicating that —CH ₂ —CH ₂ — increased in the gel; in b, the C=C—H peak of acrylamide with 990～667cm ^-1 disappeared in d, indicating that acrylamide opened the C=C double bond and interacted with sodium humate Polymerization occurs; the -COO- characteristic peaks of the gel in d at 1639cm ^-1 and 1451cm ^-1 shift to high frequency compared with sodium humate in c, indicating that the formation of hydrogen bonds in the gel in d makes C=O conjugate with the aromatic system In addition, the absorption peak at 3199cm ^-1 in b-acrylamide was not found in a-gel, and the double peak of alkyl ether R—O—R’ in a-carboxymethyl starch sodium was 1162cm ^-1 and 1081cm ^{-1 present a single peak of 1112cm -1 in} the d-gel.

Example 1: At room temperature, add sodium humate to deionized water, fully dissolve through ultrasonic oscillation, and use rapid qualitative filter paper to filter the sodium humate solution to ensure that the sodium humate solution used in the experiment does not contain water-insoluble components. The filtered sodium humate solution was dried in a drying oven at 60°C and set aside.

Take 2.5 parts of sodium humate, add 100 parts of water, and fully dissolve through ultrasonic vibration; then add 8 parts of acrylamide, 2 parts of sodium carboxymethyl starch, 1.3 parts of N,N'-methylenebisacrylamide and 3 parts of ammonium persulfate Parts are added to the sodium humate solution in turn, and finally 1.7 parts of NaOH solution with a mass fraction of 29.385% are added. Stir at a constant temperature of 25°C for 15 minutes to fully mix the ingredients, then transfer the mixture into a washed and dried test tube, and seal it with plastic wrap. Place the test tube in a water bath and raise the temperature from 25°C to 60°C, and keep the temperature constant for 3h. By inverting the test tube and taking no obvious flow of the mixed system as the judging condition, determine the gel formation. The gel was taken out, and dried in a blast drying oven at 60° C. to a constant weight to obtain a xerogel.

Embodiment 2: At room temperature, add sodium humate to deionized water, fully dissolve through ultrasonic oscillation, and use rapid qualitative filter paper to filter the sodium humate solution to ensure that the sodium humate solution used in the experiment does not contain water-insoluble components. The filtered sodium humate solution was dried in a drying oven at 60°C and set aside.

Take 7.5 parts of sodium humate, add 100 parts of water, and fully dissolve through ultrasonic vibration; then add 8 parts of acrylamide, 4 parts of sodium carboxymethyl starch, 1.3 parts of N,N'-methylenebisacrylamide and 3 parts of ammonium persulfate Parts, sequentially added to the sodium humate solution, and finally added 4.3 parts of NaOH solution with a mass fraction of 29.385%. Stir at a constant temperature of 25°C for 15 minutes to fully mix the ingredients, then transfer the mixture into a washed and dried test tube, and seal it with plastic wrap. Place the test tube in a water bath and raise the temperature from 25°C to 60°C, and keep the temperature constant for 3h. By inverting the test tube and taking no obvious flow of the mixed system as the judging condition, determine the gel formation. The gel was taken out, and dried in a blast drying oven at 60° C. to a constant weight to obtain a xerogel.

Example 3: At room temperature, sodium humate was added to deionized water, fully dissolved by ultrasonic oscillation, and fast qualitative filter paper was used to filter the sodium humate solution to ensure that the sodium humate solution used in the experiment did not contain water-insoluble components. The filtered sodium humate solution was dried in a drying oven at 60°C and set aside.

Take 5 parts of sodium humate, add 100 parts of water, and fully dissolve through ultrasonic vibration; then add 8 parts of acrylamide, 8 parts of sodium carboxymethyl starch, 1.3 parts of N,N'-methylenebisacrylamide and 3 parts of ammonium persulfate Parts, sequentially added to the sodium humate solution, and finally added 3.4 parts of NaOH solution with a mass fraction of 29.385%. Stir at a constant temperature of 25°C for 15 minutes to fully mix the ingredients, then transfer the mixture into a washed and dried test tube, and seal it with plastic wrap. Place the test tube in a water bath and raise the temperature from 25°C to 60°C, and keep the temperature constant for 3h. By inverting the test tube and taking no obvious flow of the mixed system as the judging condition, determine the gel formation. The gel was taken out, and dried in a blast drying oven at 60° C. to a constant weight to obtain a xerogel.

Example 4: At room temperature, sodium humate was added to deionized water, fully dissolved by ultrasonic oscillation, and fast qualitative filter paper was used to filter the sodium humate solution to ensure that the sodium humate solution used in the experiment did not contain water-insoluble components. The filtered sodium humate solution was dried in a drying oven at 60°C and set aside.

Take 15 parts of sodium humate, add 100 parts of water, and fully dissolve through ultrasonic vibration; then add 20 parts of acrylamide, 8.0 parts of sodium carboxymethyl starch, 1.3 parts of N,N'-methylenebisacrylamide and 3 parts of ammonium persulfate Parts, sequentially added to the sodium humate solution, and finally added 4.3 parts of NaOH solution with a mass fraction of 29.385%. Stir at a constant temperature of 25°C for 15 minutes to fully mix the ingredients, then transfer the mixture into a washed and dried test tube, and seal it with plastic wrap. Place the test tube in a water bath and raise the temperature from 25°C to 60°C, and keep the temperature constant for 3h. By inverting the test tube and taking no obvious flow of the mixed system as the judging condition, determine the gel formation. The gel was taken out, and dried in a blast drying oven at 60° C. to a constant weight to obtain a xerogel.

Finally, it should be noted that: the above descriptions are only some embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still The technical solutions recorded in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (2)

1. a kind of humic acid composite gel material, it is characterized in that：Humic acid composite gel material includes：Sodium humate, acryloyl Amine, sodium carboxymethyl starch, ammonium persulfate, N, N'-methylene-bisacrylamide and NaOH solution；The raw material proportioning is matter Ratio is measured, on the basis of 100 parts of deionized water, other raw materials include：2.5 ~ 20 parts of sodium humate, 8 ~ 20 parts of acrylamide, 2 ~ 8 parts of sodium carboxymethyl starch, 0.5 ~ 1.26 part, N of sodium hydroxide, 1 ~ 5 part of N'-methylene-bisacrylamide, persulfuric acid 0.5 ~ 3 part of ammonium.

2. the preparation method of the humic acid composite gel material described in claim 1, it is characterized in that：Composite gel material preparation side Method comprises the following steps：

A. in environment temperature 20^oUnder C ± 3, sodium humate is added into deionized water container, through supersonic oscillations, humic acid Sodium fully dissolves in deionized water, sodium humate solution is filtered using fast qualitative filter paper, it is impossible to be dissolved in deionization The sodium humate component of water filters out, and is configured to sodium humate solution；

B. acrylamide, sodium carboxymethyl starch, N, N'-methylene-bisacrylamide and ammonium persulfate are added sequentially to corruption again In sodium phytate solution, 1.7 ~ 4.3 parts of NaOH solutions prepared in advance, the NaOH solution prepared in advance are eventually adding Use and analyze pure 5.000 g NaOH and deionized water configuration quality fraction as 29.385% standard solution of sodium hydroxide；

C. 15min is stirred at 25 DEG C of constant temperature, is sufficiently mixed each component, mixed liquor is then moved into clean and dried examination Guan Zhong, is sealed using preservative film；

D. test tube is placed in heating equipment, is warming up to 60^oC, the constant temperature 1-5h at 60 DEG C；It is inverted by test tube, with mixture System is decision condition without obvious flowing, determines gel-forming；

E. gel is taken out, is dried at 60 DEG C in air dry oven to constant weight, xerogel is made.