CN1594729A

CN1594729A - Biological enzyme deinking method for waste paper

Info

Publication number: CN1594729A
Application number: CNA2004100262890A
Authority: CN
Inventors: 赵文娟; 马齐; 徐升运; 张红艳
Original assignee: INSTITUTE OF ENZYME TECHNOLOGY OF SHANXI ACADEMY OF SCIENCES
Current assignee: INSTITUTE OF ENZYME TECHNOLOGY OF SHANXI ACADEMY OF SCIENCES
Priority date: 2004-07-02
Filing date: 2004-07-02
Publication date: 2005-03-16
Anticipated expiration: 2024-07-02
Also published as: CN1240900C

Abstract

Provided is a biological enzyme deinking method for waste paper, in which flotation applies polyoxyethylene alkyl ether as flotation auxiliary, deinking process applies compound enzyme as deinking agent. The method improves the white content of the regenerated pulp by chemistry method, which is enhanced to 5-8% higher, and the COD value of the discharged sewage reduced more than 60%. The paper pulp filtration performance is further increased and the strength is similar, thus it can meet requirement of making different papers.

Description

The enzymatic deinking method of waste paper

Technical field

The invention belongs to the improvement of the deinking technology in the pulping and paper-making, relate to the applied technical field of biotechnology in pulping and paper-making.

Background technology

Traditional deinking technology is to adopt alkali electroless deinking method at present, and its maximum worn-out end is that sewage effluent COD (COD value) is high, seriously polluted, and the secondary stock that reclaims is of poor quality, does not reach instructions for use.In recent years, along with paper technology, printing-ink technology rapid development, chemistry deinking method has run into an insurmountable difficult problem again: account for wastepaper its used printing ink of untouchable waste paper (xerography and laser stamping paper) more than 80% and select for use special thermoplasticity synthetic resin to do to be connected material, after solidifying, because the crosslinked firm three-dimensional-structure that becomes takes place, alkali resistance increases greatly, and traditional alkaline process deinking process works hardly to them.

Later 1980s, utilize biology enzyme to carry out the attention that the deinking technology has caused people.Because the unicity and the technological problems of selected enzyme preparation make its financial cost and secondary stock quality all not reach desirable requirement.T.W.Jeffries, et al, Tappi J., 1994,77 (4): 173-179 has reported the enzyme process Deinking Technology of xerography and laser stamping paper, the regenerated paper pulp cleanliness factor that its simple hemicellulase deinking obtains is not high.Chinese patent discloses " utilizing the bioanalysis deinking to make waste paper regenerated process " (application number: CN97101654), this method adopts the mixed enzyme of cellulase and hemicellulase to handle waste paper, make the whiteness of regenerated paper pulp improve 21.2% (old newspaper) and 2.9% (old wastepaper) respectively, but it is unexposed in this patent document to enzyme dosage, and selected enzyme preparation still need add surfactant when deinking office waste paper, and this will certainly increase the COD value of sewage effluent.(application number: CN99120426) disclose " a kind of production method that makes deinking with enzyme process ", it adopts single crude cellulase to handle waste newsprint to Chinese patent, and is very limited for disclosing of concrete technology and treatment effect in the literary composition.

Summary of the invention

The purpose of this invention is to provide a kind of more effectively waste paper enzymatic deinking method, make handle waste paper after resulting regenerated paper pulp cleanliness factor higher, reach the requirement of all kinds paper of manufacturing paper with pulp, and the COD value of sewage effluent is lower.

The step that the deinking process for waste paper that the present invention proposes includes repulping of waste paper, deinking, flotation, copies paper; Its characteristics are: the waste paper behind the size degradation is carried out the flotation first time, and condition is to starch dense 0.5～2.0% (W/V), flotation aid employing polyoxyethylene alkyl ether, flotation 5～15min under the room temperature; Add complex enzyme then and carry out deinking, condition is, starch dense 8～18%, 40～60 ℃ of temperature, PH5.0～8.0, stirring reaction 30～60min; Add that water adjustment slurry is dense to carry out the flotation second time, condition is again, starches densely 0.5～1.5%, and polyoxyethylene alkyl ether is as flotation aid, and flotation 5～15min under the room temperature copies paper then.

Complex enzyme of the present invention forms by cellulase, lipase, amylase and laccase are composite.Wherein cellulase has complete cellulose enzyme system, includes inscribe glucuroide, circumscribed glucuroide and beta-glucosidase, and its overall enzyme is applied flexibly CMCase and represented.Various enzymes have close pH scope and reaction temperature in the complex enzyme, the enzyme amount of applying flexibly of various enzymes can be adjusted within the specific limits according to the difference of waste paper composition, cellulose enzyme activity 50～200 μ/g oven dry stock wherein, lipase enzyme 80～250 μ alive/g oven dry stock, amylase enzyme 100～300 μ alive/g oven dry stock, laccase activity 100～300 μ/g oven dry stock.The complex enzyme that the present invention adds when the deinking step is a liquid enzymes; The flotation aid polyoxyethylene alkyl ether that adopts in flotation step is a non-ionic surface active agent, and its consumption is 0.1～0.5% (W/W) of oven dry stock weight.

The present invention compared with prior art improves three: 1. exclusive " two floating one take off " technological process.Add the flotation operation again one before the deinking in " repulping of waste paper-deinking-flotation " technological process of generally adopting at present, become " repulping of waste paper-flotation-deinking-flotation " technological process.2. biology enzyme is by the composite complex enzyme that forms of cellulase, lipase, amylase and laccase, increased the kind of effective enzyme, the consumption of each enzyme component realized on the basis of using quantitatively, and can adjust accordingly according to the variation of wastepaper as raw material within the specific limits.3. adopt high underflow (8～18%) deinking, enzyme reaction concentration height, the catalytic efficiency height need not add chemicals and surfactant.4. select for use efficient non-ionic surface active agent as flotation aid during flotation, efficient height, low-consuming, flotation time can shorten in the 15min.

The mechanism of action of the present invention's used complex enzyme in deinking is: cellulase and amylase mainly act on paper fiber and various starch based sizing agent, so that fiber is loose with combining of printing ink, both are easy to separate; Lipase mainly acts on the connection material in the printing-ink, makes it can be separated into fine particle, so that flotation is removed; Laccase mainly plays pigment decolouring and discoloration.Four kinds of both efficient substrates that acted on separately of enzyme preparation act synergistically again single-mindedly each other, under the condition of not adding chemicals and surfactant, reach efficient deinking purpose, and greatly reduce the COD value of sewage effluent.

The invention has the advantages that: 1. increase a flotation before deinking, the printing ink ion that dissociates in the time of making size degradation is at first removed, and adheres to again on the paper fiber avoiding, and causes and redyes, and increases the enzyme dosage of postorder.2. use complex enzyme as deinking agent, not only efficient single-minded but also have mutual synergy, printing ink to remove fully, need not add chemicals and surfactant.3. adopt high underflow during deinking, make the concentration of substrate height of enzyme effect, catalytic condition is optimized, and efficient improves, and has reduced quantity of wastewater effluent effectively.4. the polyoxyethylene alkyl ether of Cai Yonging is as flotation aid, be liquid dosage form, compare with the solid dosage forms fatty acid soaps class of prior art, do not need heat tracing equipment, use under the room temperature more convenient, the flotation efficiency height, consumption only needs half of fatty acid soaps class, flotation time is short, and not limited by hardness of water, has further reduced the COD value of sewage effluent.By as can be seen above, application of the present invention has good effect, improves percentage than the whiteness of chemical method recycled pulp and has exceeded 5～8 percentage points, and cleanliness factor improves, and dirt count descends, and the COD value of sewage effluent has reduced more than 60%; With (application number: CN97101654) patent is compared, and whiteness improves percentage and exceeded 4～5 percentage points; Pulp Drainage Properties further improves and intensity is close, can satisfy the needs of the various paper of manufacturing paper with pulp.

The specific embodiment

Below with example enforcement of the present invention is described further.

Various enzyme preparations in the enzyme process deinking are all thought rice ferment Co., Ltd available from Shanghai, and the work of cellulase (liquid dosage form) CMCase enzyme is 1050 μ/ml, adopt acetic acid-sodium-acetate buffer preparation enzyme liquid; The work of amylase (solid dosage forms) enzyme is 3000 μ/g,, adopt acetic acid-sodium-acetate buffer preparation enzyme liquid; The work of lipase (solid dosage forms) enzyme is 20000 μ/g, adopts potassium dihydrogen phosphate-sodium hydrogen phosphate buffer solution preparation enzyme liquid; The work of laccase (liquid dosage form) enzyme is 500 μ/ml, adopts sodium tartrate buffer solution preparation enzyme liquid.

Example 1: complex enzyme is handled old and useless newspaper

Old and useless newspaper adjustment behind size degradation slurry is dense to 1.5%, the polyoxyethylene alkyl ether of adding oven dry stock weight 0.2%, room temperature flotation 8min; Then paper pulp is concentrated to 10%, transfers PH to 5.5,50 ℃ of temperature, add complex enzyme enzyme liquid, cellulase amount 50 μ/g oven dry stock wherein, amylase amount 100 μ/g oven dry stock, lipase amount 100 μ/g oven dry stock, laccase amount 100 μ/g oven dry stock, stirring reaction 40min; It is dense to 1.5% that reaction finishes back thin up slurry, adds the polyoxyethylene alkyl ether of oven dry stock weight 0.5%, and room temperature flotation 14min copies paper then, the results are shown in following table.

	Whiteness (%ISO)	Whiteness improves percentage (%)	????CODcr ????(mg·L ^-1)
	Whiteness (%ISO)	Whiteness improves percentage (%)	????CODcr ????(mg·L ^-1)	Blank (directly copying sheet after the making beating)	????41.8
Chemistry deinking slurry	????48.9	????17.0	????426	Blank (directly copying sheet after the making beating)	????41.8
Chemistry deinking slurry	????48.9	????17.0	????426	Complex enzyme deinking slurry	????52.4	????25.4	????135

Wherein, the drug dosage of chemical deinking (being the weight ratio of every gram oven dry stock): NaOH 1.0%; Na ₂SiO ₃2.5%; H ₂O ₂1.5%

Example 2: complex enzyme is handled the waste and old paper in the office that contains 80% above xerography and laser printing

Slurry is dense to 2% with regulating behind the waste and old paper in the office size degradation, adds 0.2% polyoxyethylene alkyl ether, room temperature flotation 6min; Then paper pulp is concentrated to 18%, transfers PH to 7,55 ℃ of temperature, add complex enzyme enzyme liquid: cellulase amount 150 μ/g oven dry stock wherein, amylase amount 300 μ/g oven dry stock, lipase amount 200 μ/g oven dry stock, laccase amount 250 μ/g oven dry stock, stirring reaction 60min; , it is dense to 1.5% that reaction finishes back thin up slurry, adds the polyoxyethylene alkyl ether of oven dry stock weight 0.5%, and room temperature flotation 15min copies paper then, the results are shown in following table.

	Whiteness (%ISO)	Whiteness raising rate (%)	Dirt count (mm ²/m ²)	????CODcr ????(mg·L ^-1)
	Whiteness (%ISO)	Whiteness raising rate (%)	Dirt count (mm ²/m ²)	????CODcr ????(mg·L ^-1)	Contrast (replacing enzyme liquid) with distilled water	????81.6		????19.2
Chemistry deinking slurry	????83.7	????2.57	????17.8	????475	Contrast (replacing enzyme liquid) with distilled water	????81.6		????19.2
Chemistry deinking slurry	????83.7	????2.57	????17.8	????475	Complex enzyme deinking slurry	????88.3	????8.21	????10.6	????153

Wherein: the drug dosage of chemical deinking (being the weight ratio of every gram oven dry stock): NaOH 1.5%;

Na ₂SiO ₃3.5%; Ethylenediamine tetra-acetic acid 0.2%; H ₂O ₂2.0%.

Claims

1, a kind of enzymatic deinking method of waste paper, adopt repulping of waste paper is arranged, deinking, flotation, the step of copying paper; It is characterized in that: the waste paper behind the size degradation is carried out the flotation first time, and condition is to starch dense 0.5～2..0%, flotation aid employing polyoxyethylene alkyl ether, flotation 5～15min under the room temperature; Add complex enzyme then and carry out deinking, condition is, starch dense 8～18%, 40～60 ℃ of temperature, PH5.0～8.0, stirring reaction 30～60min; Add that water adjustment slurry is dense to carry out the flotation second time, condition is again, starches densely 0.5～2.0%, and polyoxyethylene alkyl ether is as flotation aid, and flotation 5～15min under the room temperature copies paper then.

2, de-inking method according to claim 1 is characterized in that: described complex enzyme is a liquid enzymes; The enzyme amount of applying flexibly of its various enzymes is cellulose enzyme activity 50～200 μ/g oven dry stock, lipase enzyme 80～250 μ alive/g oven dry stock, amylase enzyme 100～300 μ alive/g oven dry stock, laccase activity 100～300 μ/g oven dry stock.

3, de-inking method according to claim 1 is characterized in that: the consumption of described flotation aid polyoxyethylene alkyl ether is the 0.1-0.5% of oven dry stock weight.