In-situ doped nanometer calcium carbonate chitin hydrogel, and preparation method and application thereof

A nano-calcium carbonate and in-situ doping technology, which is applied in the field of material chemistry, can solve the problems of strong alkali equipment corrosion, high price, and application limitations, and achieve the effects of enhanced adsorption performance, fast desorption speed, and good dissolution effect

Active Publication Date: 2020-01-07
GUANGXI UNIV FOR NATITIES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Nevertheless, the weak mechanical properties of chitin hydrogels greatly limit their practical applications.
In recent years, through nanofilling and compounding with other synthetic polymers, the mechanical properties of chitin composite hydrogels have been improved to a certain extent, but the improvement is limited, even at the expense of the inherent properties of chitin (such as biocompatibility, biological degradability, etc.) at the expense of
In addition, because chitin is soluble in concentrated hydrochloric acid / phosphoric acid / sulfuric acid / acetic acid, insoluble in alkali and other organic solvents, and insoluble in water, its application is greatly restricted.
The solvents of chitin reported at present include: ionic liquid, lithium chloride / strong polar solvent, strong polar fluoride solvent, saturated calcium chloride / methanol and other solvents, but they are expensive, difficult to recycle, strong volatility, etc. Restricted by shortcomings, it is difficult to popularize and apply
For example, the invention patent with application number CN201310034088.4 discloses a solvent composition for dissolving chitin, which is an aqueous solution containing 2-50wt% KOH, 0-20wt% urea, 0-6wt% thiourea, 0- 10wt% LiOH, 0-20wt% NaOH, the balance is water, although it has a good dissolving effect on chitin, but the strong alkali in it often causes corrosion of equipment

Method used

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  • In-situ doped nanometer calcium carbonate chitin hydrogel, and preparation method and application thereof
  • In-situ doped nanometer calcium carbonate chitin hydrogel, and preparation method and application thereof
  • In-situ doped nanometer calcium carbonate chitin hydrogel, and preparation method and application thereof

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Experimental program
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Effect test

Embodiment 1

[0048] A preparation method of in-situ doped nano calcium carbonate chitin hydrogel, comprising the following steps:

[0049] (1) dissolving chitin: first according to 15wt%Na 2 CO 3 / 10wt%Ca(OH) 2 Prepare the solution at a ratio of 4 wt% urea to obtain 100ml of solvent, then add 2g of chitin to the solvent, stir evenly, then freeze at -40°C for 12h, then thaw, repeat 3 times to obtain a viscous mixture;

[0050] (2) Preparation of preliminary hydrogel: Stir the viscous mixture evenly, then filter to obtain the filtrate, add 7g of epichlorohydrin to the filtrate for cross-linking reaction, the reaction temperature is 0°C, and the reaction time is 1.5h, and then the The obtained solution was introduced into the mold, and placed at room temperature for 4 hours to obtain a preliminary hydrogel;

[0051] (3) Preparation of hydrogel: Soak the preliminary hydrogel at -4°C for 10 h in a mixture of ethanol / water with a volume ratio of 1:1, and then wash until neutral to obtain a hy...

Embodiment 2

[0055] A preparation method of in-situ doped nano calcium carbonate chitin hydrogel, comprising the following steps:

[0056] (1) dissolving chitin: first according to 30wt%Na 2 CO 3 / 20wt%Ca(OH) 2 Prepare the solution at a ratio of 6 wt% urea to obtain 100ml of solvent, then add 3g of chitin to the solvent, stir evenly, then freeze at -39°C for 12 hours, then thaw, repeat 4 times to obtain a viscous mixture;

[0057] (2) Preparation of preliminary hydrogel: Stir the viscous mixture evenly, then filter to obtain the filtrate, add 7.5g epichlorohydrin to the filtrate to carry out cross-linking reaction, the reaction temperature is 2°C, the reaction time is 2h, and then the The obtained solution was introduced into the mold, and placed at room temperature for 5 hours to obtain a preliminary hydrogel;

[0058] (3) Preparation of hydrogel: Soak the preliminary hydrogel at -2°C for 12 hours in a mixture of ethanol / water with a volume ratio of 3:1, and then wash until neutral to ...

Embodiment 3

[0062] A preparation method of in-situ doped nano calcium carbonate chitin hydrogel, comprising the following steps:

[0063] (1) dissolving chitin: first according to 20wt%Na 2 CO 3 / 15wt%Ca(OH) 2 Prepare the solution at a ratio of 3 wt% urea to obtain 100ml of solvent, then add 1g of chitin to the solvent, stir evenly, then freeze at -38°C for 12h, then thaw, repeat twice to obtain a viscous mixture;

[0064] (2) Preparation of preliminary hydrogel: Stir the viscous mixed solution evenly, then filter to obtain the filtrate, add 4g epichlorohydrin to the filtrate to carry out cross-linking reaction, the reaction temperature is 4°C, the reaction time is 1h, and then the obtained The solution was introduced into the mold and placed at room temperature for 3 hours to obtain a preliminary hydrogel;

[0065] (3) Preparation of hydrogel: Soak the preliminary hydrogel at 0° C. for 15 hours with a mixture of ethanol / water with a volume ratio of 5:1, and then wash until neutral to ...

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Abstract

The invention discloses an in-situ doped nanometer calcium carbonate chitin hydrogel, and a preparation method and an application thereof. The preparation method comprises the following steps: dissolving chitin in an aqueous solution of Na2CO3 / Ca(OH)2 / urea, carrying out a chemical crosslinking reaction to prepare a preliminary hydrogel, carrying out a physical crosslinking reaction to prepare a hydrogel, and freeze-drying the hydrogel to obtain the in-situ doped nanometer calcium carbonate chitin hydrogel. The aqueous solution of Na2CO3 / Ca(OH)2 / urea is used as the solvent of chitin, so that the problem of strong corrosion of an alkali / urea aqueous solvent system used as the solvent is solved, the cost is low, and the dissolving effect on chitin is good. The in-situ doped nanometer calciumcarbonate chitin hydrogel has the advantages of good mechanical properties, good adsorption property to heavy metal ions, and excellent repeated utilization rate, and is suitable for being promoted and applied in heavy metal sewage treatment.

Description

technical field [0001] The invention belongs to the field of material chemistry, and in particular relates to an in-situ doped nano-calcium carbonate chitin hydrogel and a preparation method and application thereof. Background technique [0002] With the rapid development of modern industry, a large amount of heavy metal sewage is added every day. Machinery manufacturing, chemical industry, instrumentation, semiconductor, electronics and other industries will discharge wastewater containing heavy metals. The heavy metals in wastewater are mainly copper, zinc, cadmium, Nickel, Mercury, etc. Different from organic oils in sewage, this type of heavy metal ion is a non-biodegradable substance, so it cannot be treated by degradation methods. The methods commonly used in industry include chemical precipitation and ion exchange. After the heavy metal concentration is lower than the emission standard, it can be discharged. Among them, the adsorption method is considered to be a mo...

Claims

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Application Information

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IPC IPC(8): C08J9/28C08J3/075C08L5/08C08K3/26C02F1/28C02F101/20
CPCC08J9/286C08J3/075C02F1/286C08K2003/265C08K2201/011C08J2305/08C08J2201/0482C08J2201/0484C02F2101/20
Inventor 廖安平魏雅男李媚蓝平马汉楼蓝丽红覃琴兰雄雕卢彦越廖业欣
Owner GUANGXI UNIV FOR NATITIES
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