CN108611898B - A kind of method and application of preparing carboxymethyl fiber by water-borne method - Google Patents

Abstract

The invention discloses a method for preparing carboxymethyl fiber by using a water medium method and application thereof, which comprises the steps of dissolving an etherifying agent in water, uniformly mixing plant fibers, soaking at 30-70 ℃ for 1-6 hours to ensure that the etherifying agent is fully contacted with the plant fibers, wherein the mass ratio of the plant fibers to the etherifying agent is 1 (0.1-2), 0.1-2g of the etherifying agent is dissolved in L water of every 3-10m, then dissolving alkali in water to form an alkali solution, adding the alkali solution into the soaked material, carrying out etherification reaction for 1-6 hours at the etherification temperature of 30-90 ℃, wherein the mass ratio of the plant fibers to the alkali is 1 (0.1-2), 0.1-2g of the alkali is dissolved in L water of every 3-10m, and finally washing the reacted product to the pH value of 6-8 to obtain the carboxymethyl fiber.

Description

A kind of method and application of preparing carboxymethyl fiber by water-borne method

technical field

The invention relates to the field of heavy metal ion adsorption, in particular to a method for preparing carboxymethyl fibers by a water-borne method and application thereof.

Background technique

With the rapid development of modern economy and society, the amount of urban domestic sewage, industrial and agricultural wastewater and various mining wastewater continues to increase, and the problem of heavy metal ion pollution in water is becoming more and more serious. Among the methods for treating heavy metal ions in wastewater, adsorption method has been widely studied and applied due to its low cost, good effect and strong operability. After the solid adsorbent adsorbs the heavy metal ions in the water body, it is easy to achieve separation from the water body through simple solid-liquid filtration, so as to achieve the purpose of purifying water quality. For example: activated carbon, modified polyacrylonitrile fiber, etc. However, these commonly used adsorbents have some deficiencies in the use process. For example, activated carbon is used as an adsorbent material, which is generally made into a thicker filter layer, so that the water body can achieve the adsorption of heavy metal ions through the activated carbon filter layer. When it is used for a period of time, the filter layer needs to be replaced, which takes a long time and requires a lot of work, and the activated carbon is relatively expensive, which is not conducive to the reduction of production costs. When using modified polyacrylonitrile fibers, modified polyvinyl alcohol fibers, etc. for heavy metal ion adsorption, the heavy metal ion adsorbents of these fibers can be directly added to the water body, and after the heavy metal ions are adsorbed, pumped to the inclined screen for filtration. At the same time of continuous work, solid-liquid separation is realized, but these fibers are all synthetic fibers, which have poor biodegradability and are prone to secondary pollution.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the existing heavy metal ion adsorption materials, the present invention provides a method for preparing carboxymethyl fibers by using a water-borne method and application thereof. While realizing the carboxylation of plant fibers, the etherification substitution degree of the plant fibers is controlled to retain its carboxymethyl fibers. Fiber morphology, making it suitable for the adsorption treatment of heavy metal ions. In making full use of the advantages of fiber-based heavy metal ion adsorption materials, the greening of adsorption materials is realized.

To achieve the above object, the present invention adopts the following technical solutions:

A method for preparing carboxymethyl fiber by a water-borne method, comprising the following steps:

1) Raw material impregnation

Dissolve the etherifying agent in water, mix it evenly with the plant fibers, and soak it at 30-70°C for 1-6 hours to fully contact the etherifying agent with the plant fibers. The mass ratio of the plant fibers and the etherifying agent is 1: (0.1-2), and dissolve 0.1-2g etherifying agent into every 3-10mL water;

2) Etherification

The alkali is first dissolved in water to form an alkali solution, and the alkali solution is added to the impregnated material. At an etherification temperature of 30-90 ° C, the etherification reaction is carried out for 1-6 hours, and the mass ratio of the plant fiber to the alkali is 1 : (0.1-2), and dissolve 0.1-2g of alkali into every 3-10mL of water;

3) Washing

The product after the reaction in step 2) is washed to a pH value of 6-8 to obtain carboxymethyl cellulose.

Further, the plant fiber is softwood fiber, hardwood fiber, wheat straw fiber or bamboo fiber.

Further, the etherifying agent is sodium chloroacetate or chloroacetic acid.

Further, the alkali is sodium hydroxide, potassium hydroxide or lithium hydroxide.

Further, the aspect ratio of the prepared carboxymethyl fibers is (100-15):1.

Further, the degree of substitution of the prepared carboxymethyl fibers is 0.02-0.3.

Application of carboxymethyl cellulose in the adsorption of heavy metal ions.

Further, the heavy metal ion is Zn ²⁺ .

Compared with the prior art, the present invention has the following beneficial technical effects:

While realizing the carboxylation of plant fibers, the invention retains the fiber shape by controlling the degree of etherification substitution of the plant fibers, and the hydroxyl groups on the cellulose are replaced by carboxyl groups during the etherification process, thereby increasing the negative charge on the surface of the fibers, which is beneficial to It has electrostatic adsorption with positively charged heavy metal ions. At the same time, due to the large steric hindrance and good water solubility of the carboxyl group, the pore size and water retention value of the fiber increase, and the van der Waals force between the fiber and the heavy metal ions is enhanced. , which is more conducive to the physical adsorption between fibers and heavy metal ions, and in the adsorption test, when the substitution degree of carboxymethyl fibers reaches 0.28, the adsorption amount of Zn ²⁺ reaches 25.64 mg/g. Therefore, it can be used for the adsorption treatment of heavy metal ions, and on the basis of making full use of the advantages of fiber-based heavy metal ion adsorption materials, the greening of the adsorption materials can be realized.

Detailed ways

Embodiments of the present invention are described in further detail below:

A method for preparing carboxymethyl fiber by a water-borne method, comprising the following steps:

1) Raw material impregnation

Dissolve the etherifying agent in water, mix it evenly with the plant fibers, and soak it at 30-70°C for 1-6 hours to fully contact the etherifying agent with the plant fibers. The mass ratio of the plant fibers and the etherifying agent is 1: (0.1-2), and dissolve 0.1-2g etherifying agent into every 3-10mL water;

The plant fiber is one of softwood fiber, hardwood fiber, wheat straw fiber and bamboo fiber, and the etherifying agent is sodium chloroacetate or chloroacetic acid.

2) Etherification

The alkali is first dissolved in water to form an alkali solution, and the alkali solution is added to the impregnated material. At an etherification temperature of 30-90 ° C, the etherification reaction is carried out for 1-6 hours, and the mass ratio of the plant fiber to the alkali is 1 : (0.1-2), and dissolve 0.1-2g of alkali into every 3-10mL of water;

The alkali is sodium hydroxide, potassium hydroxide or lithium hydroxide.

3) Washing

Washing the reaction product in step 2) to a pH value of 6-8, to obtain carboxymethyl fiber; the aspect ratio of the prepared carboxymethyl fiber is (100-15): 1, and the degree of substitution is 0.02-0.3 .

Below in conjunction with embodiment, the present invention is described in further detail:

Example 1

Weigh 10g of softwood fiber and put it in a beaker, dissolve 1g of sodium chloroacetate in 30ml of water, mix the two evenly, and soak at 30°C for 6 hours to fully contact the sodium chloroacetate solution with the softwood fiber.

Weigh 1g of sodium hydroxide and dissolve it in 30ml of water, add it to the impregnated material, stir to mix evenly, etherify at 90°C for 1h, and wash with water to pH 7 after the reaction to obtain the product. The degree of substitution of the product was 0.08, and the adsorption capacity of Zn ²⁺ was 8.10 mg/g.

Example 2

Weigh 10g of hardwood fiber and put it in a beaker, dissolve 20g of chloroacetic acid in 100ml of water, mix the two evenly, and soak at 70°C for 1 hour to fully contact the chloroacetic acid solution with the hardwood fiber.

Weigh 5g of potassium hydroxide and dissolve it in 60ml of water, add it to the impregnated material, stir to mix evenly, etherify at 30°C for 6h, and wash with water to pH 6 after the reaction to obtain the product. The degree of substitution of the product was 0.18, and the adsorption capacity of Zn ²⁺ was 15.08 mg/g.

Example 3

Weigh 10g of wheatgrass fiber into a beaker, dissolve 12.5g of sodium chloroacetate in 80ml of water, mix the two evenly, and soak at 60°C for 3 hours to fully contact the sodium chloroacetate solution with the wheatgrass fiber.

Weigh 20g of lithium hydroxide and dissolve it in 100ml of water, add it to the impregnated material, stir to make it evenly mixed, etherify at 80°C for 2h, and wash with water to pH 7 after the reaction to obtain the product. The degree of substitution of the product was 0.21, and the adsorption capacity of Zn ²⁺ was 16.96 mg/g.

Example 4

Weigh 10g of bamboo fiber and put it in a beaker, dissolve 12.5g of sodium chloroacetate in 100ml of water, mix the two evenly, and soak at 50°C for 3 hours to fully contact the sodium chloroacetate solution with the bamboo fiber.

Weigh 7.5g of lithium hydroxide and dissolve it in 80ml of water, add it to the impregnated material, stir to make it evenly mixed, etherify for 4h at 80°C, and wash with water to pH 8 after the reaction to obtain the product. The degree of substitution of the product was 0.28, and the adsorption capacity of Zn ²⁺ was 25.64 mg/g.

Claims (4)

1. a method utilizing water-borne method to prepare carboxymethyl fiber, is characterized in that, comprises the following steps: 1) Raw material impregnation Dissolve the etherifying agent in water, mix it evenly with the plant fibers, and soak it at 30-70°C for 1-6 hours to fully contact the etherifying agent with the plant fibers. The mass ratio of the plant fibers and the etherifying agent is 1: (0.1-2), and dissolve 0.1-2g of etherifying agent in every 3-10 mL of water, and the etherifying agent is sodium chloroacetate or chloroacetic acid; 2) Etherification The alkali is first dissolved in water to form an alkali solution, and the alkali solution is added to the impregnated material. At an etherification temperature of 30-90 ° C, the etherification reaction is carried out for 1-6 hours, and the mass ratio of the plant fiber to the alkali is 1 : (0.1-2), and dissolve 0.1-2g of alkali into every 3-10mL of water; 3) Washing Step 2) The product after the reaction is washed with water to a pH value of 6-8, that is, water-insoluble carboxymethyl fibers are obtained, and the prepared carboxymethyl fibers have an aspect ratio of (100-15): 1, and replace the Degree is 0.02-0.3. 2. a kind of method utilizing water-borne method to prepare carboxymethyl fiber according to claim 1, is characterized in that, described plant fiber is softwood fiber, hardwood fiber, wheat straw fiber or bamboo fiber. 3. a kind of method utilizing water-borne method to prepare carboxymethyl fiber according to claim 1, is characterized in that, described alkali is sodium hydroxide, potassium hydroxide or lithium hydroxide. 4. The application of the carboxymethyl fiber prepared by the method according to any one of claims 1-3 in heavy metal ion adsorption, wherein the heavy metal ion is Zn ²⁺ .