CN100593599C

CN100593599C - Method for extracting cellulose from straw

Info

Publication number: CN100593599C
Application number: CN200710063423A
Authority: CN
Inventors: 黄勇; 于慧; 刘瑞刚
Original assignee: Institute of Chemistry CAS
Current assignee: Institute of Chemistry CAS
Priority date: 2007-01-31
Filing date: 2007-01-31
Publication date: 2010-03-10
Anticipated expiration: 2027-01-31
Also published as: CN101235604A

Abstract

The invention relates to a method for abstracting cellulose from non-woody plants fiber raw materials such as straws and the like and in particular relates to a method for removing silicon and ligninto abstract the cellulose from the straws. The invention can simultaneously remove the silicon, the lignin and the like from the straws and can obtain the cellulose through processing organic solvent,inorganic alkaline solution, oxidizing solution and the like.

Description

From stalk, extract cellulosic method

Invention field

The present invention relates to a kind of cellulosic method and cellulose of gained thus of from nonwood plant fiber sources such as stalk, extracting.Specifically, the present invention relates to by from stalk, removing the cellulosic method of silicon and lignin extraction simultaneously.

Background technology

Because the ecological balance wrecks; desertification is serious day by day; requirement to environmental protection and sustainable development is more and more higher; crop residues such as straw plant such as straw, rice straw is as new native cellulose source and the alternative materials that is used for paper industry fiber timber; be easy to get owing to it is very inexpensive, just receiving increasing the concern and research.

Compare with timber, contain the higher silicon composition of relative amount in the stalk plant.Be generally with Mechanical Method and remove silicon for from the higher stalk class material of silicone content, extracting cellulose in the prior art, carry out with the method for alkali lye boiling then, this method power consumption and pollute (cellulose science, noble and unsullied, Tang Liegui volume, 1996, the 18 pages).And this method has very most silicon and residues on the cellulose fibre in pulping process, can not effectively remove delignification simultaneously.The cellulosic quality that a large amount of residual influences of lignin is extracted.Correspondingly, gained paper toughness is not enough and be difficult to bleaching when being used for papermaking, can only produce low-qualityer paper.And reclaim the black liquor that comprises a large amount of silicate consumes energy very much.In addition, have report only to use hydrogen peroxide progressively to extract cellulosic method, but its reaction condition is complicated and have relatively high expectations (Sun etc., Industrial Crops ﹠amp; Products, 2000,12:p71).

So, need seek a kind of method in this area, make also to go out delignification when from stalk fibrid, removing silicon under the condition of simple reaction, thereby obtain comparatively pure cellulose in gentleness.

Summary of the invention

The object of the present invention is to provide a kind of silicon of from stalk class nonwood plant fiber sources, removing also to remove delignification simultaneously, thereby extract cellulosic method.

Employed term " nonwood plant " refers to the non-ligno-cellulosic materials that derives from xylophyta among the present invention, comprises remaining stalk of crops annual or perennial grass class and annual harvesting such as straw, rice straw, cornstalk etc.

Of the present inventionly extract cellulosic method can remove silicon in the stalk and lignin etc. simultaneously from stalk, this method may further comprise the steps:

(1) under the reflux temperature of employed organic solvent, the stalk raw material is handled to extract the wax on stalk raw material surface with suitable organic solvent;

(2) the stalk raw material that step (1) was handled leach, with concentration is the stalk raw material that the inorganic alkaline solution soaking of 3～6wt% leaches, soak time is 10～20 hours, removes the non-cellulose materials such as silicon, hemicellulose and pectin in the stalk raw material; The stalk raw material are filtered and dehydration;

(3) at room temperature, the stalk raw material that step (2) is obtained are that 4～6 oxidizing solution is bleached processing with the pH value, to remove lignin wherein and further to remove wherein other non-cellulose composition;

(4) the stalk raw material that step (3) was handled are soaked in the processing of spending the night in 3～6wt% inorganic alkali solution, and further to remove the non-cellulose component in the material, water is rinsed well and be dry afterwards, obtains the comparatively pure cellulose of white.

Wherein, before step (1) is handled the stalk raw material, at first raw material are carried out mechanical separation, remove the tubercle part of the stalk that contains a large amount of silicon, gained internode part can use the grinding mode of any routine to pulverize.

In step (1), used organic solvent should be easy to combine with wax and have volatility, and it is acetone, ethanol, toluene, chloroform or their any mixture.Extracting mode is extraction process preferably, wherein advantageously temperature is controlled at the reflux temperature of this organic solvent or ORGANIC SOLVENT MIXTURES.

In step (2), the gained material is filtered well known to a person skilled in the art mode, be preferably suction filtration.Then will leach thing and immerse in the inorganic alkali lye to remove non-cellulose materials such as silicon, hemicellulose and pectin, can add proper amount of surfactant for example lauryl sodium sulfate remove efficient with increase.And then with filtration of material and dehydration.Reclaim filtrate, the suitable inorganic acid of adding neutralizes and makes the silicon precipitation in filtrate, and with its isolated by filtration, facilitates the use regenerant.

In step (3), will at room temperature carry out oxidation bleaching to remove lignin wherein and further to remove wherein other non-cellulose composition with oxidizing solution through the material of abovementioned steps.Used oxidizing solution can be selected from sodium chlorite solution or H ₂O ₂Solution etc., its concentration can be 0.3～5wt%, and the pH value is preferably 4.5～5.5.

In step (4), products therefrom at room temperature further is soaked in the inorganic alkali solution spends the night, further to remove the non-cellulose component in the material, water is rinsed well and is dry afterwards, obtains the comparatively pure cellulose of white.

Described stalk raw material are agricultural crop straw, herbaceous plant or their any mixture.

Described agricultural crop straw is selected from one or more the mixture in straw, wheat straw, maize straw, soybean stalk, cotton stalk, the sweet potato vine etc.

Described herbaceous plant is selected from one or more the mixture in the grass bits on reed, reed reed, awns bar, bamboo, lawn etc.

Described inorganic base is potassium hydroxide, NaOH and their mixture.Inorganic concentration of lye is preferably 4～5wt%, more preferably 5wt%.

In above-mentioned steps, the amount of used liquid surpasses solid fully with liquid levels and is as the criterion.Except as otherwise noted, percentage described in the present invention is weight ratio.

A little less than the characteristic peak of silicon is reduced to very in the spectrogram of the product before and after the demonstration of x-ray photoelectron power spectrum is handled, illustrate and handle its amount of back seldom.The FTIR spectrogram mainly demonstrates the cellulose characteristic absorption peak, and more weak lignin and hemicellulose characteristic absorption peak relatively only arranged.

Description of drawings

Fig. 1. the FTIR spectrogram of the embodiment of the invention 1 products therefrom.

The x-ray photoelectron power spectrum full scan figure of wheat stalk before Fig. 2 a. embodiment of the invention 1 is handled.

Fig. 2 b. embodiment of the invention 1 is handled the x-ray photoelectron power spectrum full scan figure of back wheat stalk.

The specific embodiment

Below by concrete but and non-restrictive example the present invention exemplarily is elaborated.

Embodiment 1.

It is the mixed solution backflow extracting 24 hours of 1: 1 toluene and ethanol with the 200ml volume ratio that 20g wheat stalk (removing the tubercle part of the stalk that contains a large amount of silicon) after pulverizing is put into Soxhlet extractor, be 5% KOH solution soaking gained extract product 12 hours with 180ml concentration then, gentle agitation in this process.Then, reclaim filtrate, and the product water that leaches is washed 3 times gained sample suction filtration, and then suction filtration and dehydration.It is that 0.4% sodium chlorite solution soaked 6 hours that products therefrom is put into 150ml concentration, and the pH value of regulating the solution of putting into sample is about 5.0, during gentle agitation.The suction filtration products therefrom continues to put into the processing of 5%KOH solution and spends the night then, leaches the solid in the solution.It is neutral that water fully washes to the pH value, and with products therefrom intensive drying in baking oven, obtains about 8g product.

As shown in Figure 1, the FTIR spectrum has mainly shown cellulosic characteristic absorption peak (1160cm ^-1, 1098cm ^-1, 900cm ^-1), lignin (1595cm ^-1And 1510cm ^-1) and hemicellulose (1735cm ^-1) characteristic peak relatively a little less than, illustrate that the method according to this invention has obtained comparatively pure cellulose.

Shown in Fig. 2 a and Fig. 2 b, the X-ray photoelectron spectroscopic analysis data of products therefrom show that wherein the content of the Si that represents with atomic percent drops to 0.329% by 5.019%, and wherein carbon ratio 0/C becomes 0.6986 by 0.2289, and the increase of this ratio is directly proportional with the increase of content of cellulose.

Claims

1. one kind is extracted cellulosic method from stalk, it is characterized in that this method can be removed silicon and the lignin in the stalk simultaneously, may further comprise the steps:

(1) under the reflux temperature of employed organic solvent, adopts organic solvent to carry out extracting to the stalk raw material and extract processing;

(2) the stalk raw material that step (1) was handled leach, and soak the stalk raw material that leach with inorganic alkali solution; The stalk raw material are filtered and dehydration;

(3) the stalk raw material that step (2) is obtained are that 4～6 oxidizing solution is bleached processing with the pH value;

(4) the stalk raw material that step (3) was handled are soaked in the processing of spending the night in the inorganic alkali solution, and water is rinsed well and be dry afterwards, obtains cellulose;

Described organic solvent is acetone, ethanol, toluene, chloroform or their any mixture;

The concentration of described inorganic alkali solution is 3～6wt%; Inorganic base is potassium hydroxide, NaOH or their mixture;

Described oxidizing solution is selected from sodium chlorite solution or H ₂O ₂Solution;

Described stalk is the internode part of stalk.

2. method according to claim 1 is characterized in that: the concentration of described inorganic alkali solution is 4～5wt%.

3. method according to claim 1 is characterized in that: the pH value of described oxidizing solution is 4.5～5.5.

4. method according to claim 1 is characterized in that: described stalk is the herbaceous plant after pulverizing.

5. method according to claim 4 is characterized in that: described herbaceous plant is an agricultural crop straw.