CN111676723A - Microwave-hot alkali pretreatment assisted wood delignification method - Google Patents

Microwave-hot alkali pretreatment assisted wood delignification method Download PDF

Info

Publication number
CN111676723A
CN111676723A CN202010553990.7A CN202010553990A CN111676723A CN 111676723 A CN111676723 A CN 111676723A CN 202010553990 A CN202010553990 A CN 202010553990A CN 111676723 A CN111676723 A CN 111676723A
Authority
CN
China
Prior art keywords
wood
delignification
solution
microwave
treatment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010553990.7A
Other languages
Chinese (zh)
Inventor
林涛
王忠祥
殷学风
范晶
张能
王俊
张聪
魏潇瑶
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shaanxi University of Science and Technology
Original Assignee
Shaanxi University of Science and Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shaanxi University of Science and Technology filed Critical Shaanxi University of Science and Technology
Priority to CN202010553990.7A priority Critical patent/CN111676723A/en
Publication of CN111676723A publication Critical patent/CN111676723A/en
Pending legal-status Critical Current

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
    • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
    • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
    • B27K5/003—Treating of wood not provided for in groups B27K1/00, B27K3/00 by using electromagnetic radiation or mechanical waves
    • B27K5/0055—Radio-waves, e.g. microwaves
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/02—Pretreatment of the raw materials by chemical or physical means
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/02—Pretreatment of the raw materials by chemical or physical means
    • D21B1/021—Pretreatment of the raw materials by chemical or physical means by chemical means
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor

Abstract

A microwave-hot alkali pretreatment method for assisting wood delignification comprises the following steps: 1) wood chip pretreatment: adjusting the water content of the prepared wood chips to 60-100% by alkali liquor; then carrying out microwave treatment; 2) the pretreated wood chips are washed to be neutral by deionized water and then are placed in NaClO2In the solution, the pH of the solution is adjusted by glacial acetic acid, and then the solution is heated for delignification treatment. The invention can accelerate the delignification treatment time of the wood and improve the treatment efficiency by pretreating the wood with the microwave-alkali liquor.

Description

Microwave-hot alkali pretreatment assisted wood delignification method
Technical Field
The invention relates to a pulping and papermaking technology, in particular to a pretreatment method for wood delignification.
Background
The wood is a rich, environment-friendly and renewable green structural material, the functional material prepared by taking the wood as a base material meets the requirement of sustainable development, delignified wood is mostly taken as a base plate in a plurality of functional materials, but the delignification time required by the existing wood delignification process is long, and the efficiency is low. The existing delignification process is to place wood chips in sodium chlorite with the mass fraction of 2-5%, add glacial acetic acid to adjust the pH value to 4-5, and treat the wood chips for 12 hours at about 90 ℃. The delignification process does not carry out pretreatment before the delignification of the wood chips, so that the permeability of the liquid medicine of the wood chips is poor, and therefore, in order to achieve a more ideal delignification effect, the delignification time is longer, and the long delignification time is unfavorable for maintaining the structural integrity of the wood chips.
How to shorten the delignification time of the wood and improve the delignification efficiency is one of the problems to be solved urgently in the preparation process of the functional material taking the delignified wood as a substrate.
Disclosure of Invention
The invention aims to provide a wood delignification treatment method, which realizes the shortening of the treatment time and treatment efficiency of wood delignification by adding wood pretreatment before the delignification treatment method.
In order to achieve the purpose, the technical scheme provided by the invention is a method for assisting wood delignification by microwave-hot alkali pretreatment, which comprises the following steps:
1) wood chip pretreatment: adjusting the water content of the prepared wood chips to 60-100% by 5-9 wt% NaOH solution; then carrying out microwave treatment, wherein the microwave power is 400-600 w, and the microwave treatment lasts for 60-120 s;
2) the pretreated wood chips are washed to be neutral by deionized water and then are placed into 3 to 7 weight percent of NaClO2In the solution, the pH value of the solution is adjusted to 3-5 by glacial acetic acid, and then the solution is heated in a water bath at 70-90 ℃ to carry out delignification treatment.
And washing the delignified wood chips with deionized water to be neutral and then drying.
The invention carries out microwave-alkali liquor pretreatment on the wood before delignification treatment, combines a physical and chemical pretreatment method, and carries out swelling on the wood through alkali liquor and OH through OH-Can make part of lignin macromolecular structure break down, directly remove part of lignin, make the ester bond inside the timber take place saponification reaction, improve timber porosity, OH in addition-Can generate new negative oxygen ions to activate lignin, so that the lyophilic property of the lignin is enhanced, and the subsequent delignification can be rapidly and efficiently carried out;
microwave quickly vaporizes water molecules at various parts of the wood with certain water content to form vapor pressure, when the vapor pressure is large enough, partial weak tissues or parenchyma cells (such as ray cells of the parenchyma) of the wood are cracked to form micro cracks, and further a water migration channel is opened, so that the porosity of the wood is improved, and the permeability of liquid medicine is improved conveniently during subsequent delignification.
Therefore, the wood is pretreated by the microwave-alkali liquor, the wood delignification treatment time can be shortened, and the delignification efficiency is improved.
Detailed Description
According to the technical scheme, the wood delignification treatment method comprises the following specific steps:
1) wood chip pretreatment: adjusting the water content of the prepared wood chips to 60-100% by alkali liquor; then microwave treatment is carried out;
2) the pretreated wood chips are washed to be neutral by deionized water and then are placed in NaClO2In the solution, after the pH value of the solution is adjusted by glacial acetic acid, heating is carried out to carry out delignification treatment;
3) the delignified chips are washed to neutrality by deionized water and then dried.
The acid-insoluble lignin (Clarsen lignin) content of the delignified chips is measured by referring to the national standard GB/T2677.8-1994, and the porosity and whiteness of the delignified chips are detected.
The delignification treatment is described in detail for a better illustration and understanding of the treatment.
Example one
Wood pretreatment:
1) taking fast-growing poplar wood chips with the specification of 30mm multiplied by 2mm as a raw material, and adjusting the water content of the wood chips to 80 percent by using 6 weight percent NaOH solution in a constant-temperature constant-humidity box;
2) adjusting the power of a microwave oven to 500w, and placing the wood with the water content of 80% in the microwave oven for 120s to obtain pretreated wood;
delignification treatment:
3) after the pretreated wood is washed to be neutral by deionized water, the wood is placed in 5 wt% NaClO2In the solution, adjusting the pH value of the solution to 4 by using glacial acetic acid; will be placed in NaClO2Heating the wood in the solution in a constant-temperature water bath at 90 ℃ for 2 hours, and performing delignification treatment to obtain delignified wood;
4) the delignified wood is washed to be neutral by deionized water and then dried.
Example two
Wood pretreatment:
1) taking fast-growing poplar wood chips with the specification of 30mm multiplied by 2mm as a raw material, and adjusting the water content of the wood chips to be 60% by using 5 wt% of NaOH solution in a constant-temperature constant-humidity box;
2) adjusting the power of a microwave oven to 600w, and placing the wood with the water content of 60% in the microwave oven for 120s to obtain pretreated wood;
delignification treatment:
3) after the pretreated wood is washed to be neutral by deionized water, the wood is placed in 3 wt% NaClO2In the solution, adjusting the pH value of the solution to 4 by using glacial acetic acid; will be placed in NaClO2Heating the wood in the solution in a constant-temperature water bath at 70 ℃ for 2 hours, and performing delignification treatment to obtain delignified wood;
4) the delignified wood is washed to be neutral by deionized water and then dried.
EXAMPLE III
Wood pretreatment:
1) taking fast-growing poplar wood chips with the specification of 30mm multiplied by 2mm as a raw material, and adjusting the water content of the wood chips to be 100 percent by using 9 weight percent NaOH solution in a constant-temperature constant-humidity box;
2) adjusting the power of a microwave oven to 600w, and placing the wood with the water content of 100% in the microwave oven for 120s to obtain pretreated wood;
delignification treatment:
3) after the pretreated wood is washed to be neutral by deionized water, the wood is placed in 7 wt% NaClO2In the solution, adjusting the pH value of the solution to 3 by using glacial acetic acid; will be placed in NaClO2Heating the wood in the solution in a constant-temperature water bath at 90 ℃ for 2 hours, and performing delignification treatment to obtain delignified wood;
4) the delignified wood is washed to be neutral by deionized water and then dried.
Example four
Wood pretreatment:
1) taking fast-growing poplar wood chips with the specification of 30mm multiplied by 2mm as a raw material, and adjusting the water content of the wood chips to 70% by using 5 wt% of NaOH solution in a constant-temperature constant-humidity box;
2) adjusting the power of a microwave oven to 500w, and placing the wood with the water content of 70% in the microwave oven for 60s to obtain pretreated wood;
delignification treatment:
3) after the pretreated wood is washed to be neutral by deionized water, the wood is placed in 5 wt% NaClO2In the solution, adjusting the pH value of the solution to 5 by using glacial acetic acid; will be placed in NaClO2Heating the wood in the solution in a constant-temperature water bath at 70 ℃ for 2 hours, and performing delignification treatment to obtain delignified wood;
4) the delignified wood is washed to be neutral by deionized water and then dried.
EXAMPLE five
Wood pretreatment:
1) taking fast-growing poplar wood chips with the specification of 30mm multiplied by 2mm as a raw material, and adjusting the water content of the wood chips to 80% by using 7 wt% of NaOH solution in a constant-temperature constant-humidity box;
2) adjusting the power of a microwave oven to 600w, and placing the wood with the water content of 80% in the microwave oven for 60 days to obtain pretreated wood;
delignification treatment:
3) after the pretreated wood is washed to be neutral by deionized water, the wood is placed in 6 wt% NaClO2In the solution, adjusting the pH value of the solution to 3 by using glacial acetic acid;will be placed in NaClO2Heating the wood in the solution in a constant-temperature water bath at 70 ℃ for 2 hours, and performing delignification treatment to obtain delignified wood;
4) the delignified wood is washed to be neutral by deionized water and then dried.
The effect of NaOH mainly divide into two aspects, and the first is plays the swelling effect to the timber cell, improves timber's internal surface area, lets the pore of part jam in the timber opened, makes the porosity of timber increase, improves the permeation rate of liquid medicine when being favorable to follow-up delignification. Second is OH-Can make part of lignin macromolecular structure break down, directly remove part of lignin, make the ester bond inside the timber take place saponification reaction, improve timber porosity, OH in addition-Can generate new negative oxygen ions to activate lignin, so that the lyophilic property of the lignin is enhanced, and the subsequent delignification can be rapidly and efficiently carried out.
The microwave has the function of penetrating into the wood by utilizing the good heating uniformity of the microwave in the wood delignification, so that water molecules at each position of the wood with certain water content are quickly vaporized, vapor pressure is formed in the vaporization process of the water molecules, when the vapor pressure is large enough, partial weak tissues or parenchyma cells (such as ray cells of a thin wall) of the wood are broken to form micro cracks, and further, a water migration channel is opened, the porosity of the wood is improved, and the permeability of a liquid medicine is improved conveniently during the subsequent delignification.
The microwave-thermokalite wood pretreatment is a physical and chemical pretreatment method, NaOH is added in the microwave treatment process, and the water content of the wood is adjusted by the NaOH. The microwave-hot alkali pretreatment combines the swelling effect during NaOH pretreatment with the delignification effect and the physical pore opening effect of microwave treatment. Quickens the delignification treatment efficiency of the wood and shortens the delignification time.
The method for measuring the lignin content of the delignified wood treated in the above way is carried out by referring to the national standard GB/T2677.8-1994, and comprises the following specific steps:
1) crushing the delignified wood chips by using a miniature plant sample crusher to obtain wood chips, and then controlling the size of the wood chips by using 40-mesh and 60-mesh sieves;
2) putting weighed sawdust into a beaker, adding 15mL of 72% concentrated sulfuric acid, and keeping the temperature at 18-20 ℃ for about 2 hours, and stirring the mixture when the temperature is not constant;
3) the content in the beaker is completely transferred into a 1000mL conical flask under the rinsing of deionized water, the deionized water is added until the total volume is 560mL, and the conical flask is placed on a furnace to be boiled for 4h (the volume of the solution is kept unchanged in the whole process);
4) the solution was filtered through a G2 glass filter (dried and weighed) and washed with hot distilled water until the wash solution was no longer cloudy with a few drops of 10% barium chloride and was not acidic as checked by pH paper;
5) putting the filtered G2 glass filter into a 105 ℃ oven, and drying to constant weight;
6) and taking the G2 glass filter dried to constant weight out of the oven and weighing, wherein the difference of the mass of the G2 glass filter obtained in two times is the mass of the acid-insoluble lignin, and the mass of the acid-insoluble lignin is divided by the mass of the raw material wood chips to obtain the content of the acid-insoluble lignin.
The whiteness is measured by a whiteness instrument YQ-Z-48A, the front side and the back side of each wood chip are measured, and the average value is calculated to obtain the whiteness of the wood chips.
The porosity of the wood was measured using a mercury intrusion gauge.
The measured lignin removal rate of the wood is as high as about 90%, the porosity increase rate can reach about 172%, and the whiteness increase rate can reach about 75%.
The invention has the beneficial effects that: the microwave-hot alkali pretreatment of wood combines the swelling effect during NaOH pretreatment and the delignification effect and the physical pore opening effect of microwave treatment, and the synergistic effect of the swelling effect and the delignification effect greatly promotes the subsequent delignification treatment. The method is simple to operate, has good delignification effect, can shorten the delignification time of 12 hours required in the prior delignification process to 2 hours, has the advantages of short delignification time, high efficiency, low energy consumption and low pollution, is an efficient and rapid wood delignification method, greatly improves the porosity of the wood chips on the premise of ensuring the complete structure of the wood chips after the delignification by the method, and is an ideal method for preparing the delignified wood substrate.

Claims (6)

1. A microwave-hot alkali pretreatment method for assisting wood delignification comprises the following steps:
1) wood chip pretreatment: adjusting the water content of the prepared wood chips to 60-100% by alkali liquor; then carrying out microwave treatment;
2) the pretreated wood chips are washed to be neutral by deionized water and then are placed in NaClO2In the solution, the pH of the solution is adjusted by glacial acetic acid, and then the solution is heated for delignification treatment.
2. The method according to claim 1, characterized in that the lye in step 1) is a 5 wt% to 9 wt% NaOH solution.
3. The method according to claim 1, wherein the microwave power in step 1) is 400 w-600 w, and the microwave treatment is carried out for 60-120 s.
4. The method of claim 1, wherein in step 2), the NaClO is added2The concentration of the solution is 3 wt% -7 wt%.
5. The method according to claim 1, wherein the pH of the mixture in step 2) is adjusted to 3 to 5 with glacial acetic acid.
6. The method according to claim 1, wherein in step 2), the heating is performed by heating in a water bath at 70-90 ℃.
CN202010553990.7A 2020-06-17 2020-06-17 Microwave-hot alkali pretreatment assisted wood delignification method Pending CN111676723A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010553990.7A CN111676723A (en) 2020-06-17 2020-06-17 Microwave-hot alkali pretreatment assisted wood delignification method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010553990.7A CN111676723A (en) 2020-06-17 2020-06-17 Microwave-hot alkali pretreatment assisted wood delignification method

Publications (1)

Publication Number Publication Date
CN111676723A true CN111676723A (en) 2020-09-18

Family

ID=72455312

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010553990.7A Pending CN111676723A (en) 2020-06-17 2020-06-17 Microwave-hot alkali pretreatment assisted wood delignification method

Country Status (1)

Country Link
CN (1) CN111676723A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112339049A (en) * 2020-10-27 2021-02-09 阜南县明强柳编工艺品有限公司 Treatment method for improving grain strength of willow board
CN112624781A (en) * 2020-11-23 2021-04-09 南京林业大学 Composite material based on lignocellulose and bacterial cellulose and preparation method and application thereof
CN113771166A (en) * 2021-09-29 2021-12-10 东北林业大学 Preparation method of switchable energy-consumption-free refrigeration and heating heat management wood

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101532263A (en) * 2009-04-10 2009-09-16 天津商业大学 Method for irradiating NaClO-bleached wheat straw pulp on a microwave
CN102304186A (en) * 2011-09-21 2012-01-04 张根林 Method for preparing carboxymethylcellulose sodium from cotton stalks by utilizing microwave technique
CN103103844A (en) * 2013-01-16 2013-05-15 天津理工大学 Sodium hydroxide wheat straw normal-pressure pulping method using microwave radiation
CN103924469A (en) * 2014-04-30 2014-07-16 中国石油集团东北炼化工程有限公司吉林设计院 Method for removing lignin
CN105507049A (en) * 2015-12-18 2016-04-20 吉林大学 Method for extracting cellulose out of mung bean skin
CN106283795A (en) * 2016-11-08 2017-01-04 福建农林大学 A kind of method separating hemicellulose and cellulose

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101532263A (en) * 2009-04-10 2009-09-16 天津商业大学 Method for irradiating NaClO-bleached wheat straw pulp on a microwave
CN102304186A (en) * 2011-09-21 2012-01-04 张根林 Method for preparing carboxymethylcellulose sodium from cotton stalks by utilizing microwave technique
CN103103844A (en) * 2013-01-16 2013-05-15 天津理工大学 Sodium hydroxide wheat straw normal-pressure pulping method using microwave radiation
CN103924469A (en) * 2014-04-30 2014-07-16 中国石油集团东北炼化工程有限公司吉林设计院 Method for removing lignin
CN105507049A (en) * 2015-12-18 2016-04-20 吉林大学 Method for extracting cellulose out of mung bean skin
CN106283795A (en) * 2016-11-08 2017-01-04 福建农林大学 A kind of method separating hemicellulose and cellulose

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112339049A (en) * 2020-10-27 2021-02-09 阜南县明强柳编工艺品有限公司 Treatment method for improving grain strength of willow board
CN112624781A (en) * 2020-11-23 2021-04-09 南京林业大学 Composite material based on lignocellulose and bacterial cellulose and preparation method and application thereof
CN112624781B (en) * 2020-11-23 2022-04-19 南京林业大学 Composite material based on lignocellulose and bacterial cellulose and preparation method and application thereof
CN113771166A (en) * 2021-09-29 2021-12-10 东北林业大学 Preparation method of switchable energy-consumption-free refrigeration and heating heat management wood

Similar Documents

Publication Publication Date Title
CN111676723A (en) Microwave-hot alkali pretreatment assisted wood delignification method
CN101855368B (en) Process for preparing a sugar product
CN104005247B (en) A kind of microwave cooperating prepares the method for bagasse bleached pulp
CN101148782B (en) Hemp-like bast fibre flash explosion-high temperature boiling combination degumming technique
Yuan et al. Effect of alkaline pre-extraction of hemicelluloses and silica on kraft pulping of bamboo (Neosinocalamus affinis Keng)
CN103147356B (en) Abrasive steel paperboard and manufacturing process thereof
CN105908562A (en) Method for producing translucent paper through beating enzymes
Lu et al. Combining hydrothermal-alkaline/oxygen pretreatment of reed with PEG 6,000-assisted enzyme hydrolysis promote bioethanol fermentation and reduce enzyme loading
CN108729285A (en) A kind of method of the puffing extraction bagasse hemicellulose of microwave-
CN107227643A (en) A kind of method that hydroxyl radical free radical agent for capturing improves oxygen alkali pulping effect
US3694309A (en) Lignin-preserving bleaching of cellulose pulp
CN102191707B (en) Low temperature rapid pulping process of reed
CN105058546B (en) A kind of enzymatic treatment environmental protection deal board
CN114851323B (en) Preparation method of high-strength flexible transparent bamboo material
CN110904710A (en) Bamboo pulp preparation process
Resalati et al. Effect of hot-water and mild alkaline extraction on soda-AQ pulping of wheat straw
CN110328727A (en) A kind of transparent timber and the application of the method and its preparation preparing transparent timber using organic solvent
US2999783A (en) Process for simultaneous production of high alpha-pulp with furfural from latifoliate tree materials
CN107476103A (en) A kind of method of cellulose in wood fibre pulpboard using ionic liquid extract
Cheng et al. Hot water extraction of corn stover: Hemicellulose fractionation and its effect on subsequent soda-AQ pulping
Zhu et al. Microwave-assisted Formic Acid/Cold Caustic Extraction for Separation of Cellulose and Hemicellulose from Biomass.
CN104911939A (en) Low-liquor ratio bamboo material neutral sulfite cooking method
CN106592321B (en) The method that a kind of biochemical process ECF bleached kraft pulps of Fast growth poplar prepare paper base material
Li et al. Optimization of pretreatment and alkaline cooking of wheat straw on its pulpability using response surface methodology
CN110629576A (en) Method for preparing dissolving pulp by completely chlorine-free bleaching of poplar sulfate pulp

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20200918