CA2145439A1 - Process and agent for the oxidative bleaching of wood pulp and for deinking waste paper - Google Patents
Process and agent for the oxidative bleaching of wood pulp and for deinking waste paperInfo
- Publication number
- CA2145439A1 CA2145439A1 CA 2145439 CA2145439A CA2145439A1 CA 2145439 A1 CA2145439 A1 CA 2145439A1 CA 2145439 CA2145439 CA 2145439 CA 2145439 A CA2145439 A CA 2145439A CA 2145439 A1 CA2145439 A1 CA 2145439A1
- Authority
- CA
- Canada
- Prior art keywords
- waste paper
- agent
- hydrogen peroxide
- bleaching
- deinking
- 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.)
- Abandoned
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
- 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
- D21C9/1026—Other features in bleaching processes
- D21C9/1036—Use of compounds accelerating or improving the efficiency of the processes
-
- 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
- D21C5/02—Working-up waste paper
- D21C5/025—De-inking
- D21C5/027—Chemicals therefor
-
- 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
- D21C9/16—Bleaching ; Apparatus therefor with per compounds
- D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/64—Paper recycling
Abstract
The present invention provides a process for the oxidative bleaching of wood pulps and for deinking waste paper by means of hydrogen peroxide and a stabilising agent, wherein, as stabilising agent, there is used 2-oxo-2-(4-hydroxyphenyl)-acethydroximic acid chloride (N,4-dihydroxy-.alpha.-oxophenylethanimidoyl chloride) of the formula:-
Description
21~5439 The present invention is concerned with a process for the oxidative bleaching of wood pulp and for de-inking waste paper with the help of hydrogen peroxide in the presence of a stabilising agent.
For the production of paper, besides the use of native wood pulps, to an increasing extent resource is had to recycled waste paper. The reuse of waste paper as a raw material source for the production of papers with a high degree of whiteness or brightness can only take place when, on the one hand, the coloured materials contained in the waste paper are substantially removed by rinsing out (in the following called deinking) and, on the other hand, the residues of coloured rnaterial are subjected to a chemical bleaching. Both procedures can be carried out in a common or in a multi-step process. The bleaching chemicals are used in order to destroy the chromophores present in the fibre materials, i.e. the coloured materials originating from the waste paper, as well as the dissolved and undissolved components of the printing colours. The bleaching can be carried out with oxidising and/or reducing chemicals.
Many processes for deinking and bleaching are described in the literature. A preferred process is the simult-aneous deinking and bleaching with hydrogen peroxide for waste paper and wood pulp.
The combined process is carried out, for example, with an agent of the following base composition:
2145g39 -sodium hydroxide 1.0 - 1.5% referred to atro material hydrogen peroxide 0.5 - 1.5% referred to atro material sodium silicate up to 4.0% referred to atro material complexing agent 0.1 - 0.4% referred to atro material soap 0.6 - 1.0% referred to atro material waste paper/ 0.9 - 2.0% referred to atro material wood pulp By "atro material" is to be understood the amount of the air-dried mixture of waste paper and wood pulp.
The statements of percentage are percentages by weight.
In practice, as carrier medium there is essentially reused in a cyclic process the water originating from the process. The deinking process water has, in general, a temperature of 30 to 60C.
In the first step of removing the coloured material, the pH reaches a value of 9.5 - 10.5.
The separation of fibres and printing colours is promoted by the alkaline medium. Hydrogen peroxide has proved to be an ideal bleaching agent since it bleaches especially effectively in an alkaline medium by activation of the hydroperoxide anion (see equation 1).
HO2 is the important molecule for the bleaching action Equation 1:
OH
H22 - HO2 + H+
During the process, as side reactions according to the following equation 2, there occurs a spontaneous dissociation of the hydrogen peroxide in the case of 2195~3~
`~ _ the presence of heavy metal ions or in the case of the presence of the enzyme catalase, as well as decomposition of the peroxide catalysed by peroxidases.
They reduce the degree of utilisation of the amount of hydrogen peroxide used and thereby influence the bleaching action. The result is an increased require-ment of hydrogen peroxide and aqueous sodium hydroxide solution.
Equation 2:
22 ) 2 2 2 It is known to mask the damaging action of heavy metal ions by the addition of complex formers, such as ethylenediamine-tetraacetic acid, pentetic acid (DTPA), polycarboxylic acids, for example citric acid, gluconic acid, polyacrylic acid, phosphonic acids and the like. These also serve simultaneously as flotation agents in the case of deinking (cf. DE 42 04 915 Al).
As natural products, waste paper and wood pulp are nutrient media for microbiological growth. Almost all micro-organisms which occur as a natural contamin-ation on and in waste paper and wood pulp synthesise, as cell-inherent enzy~les, catalases and various peroxidases.
Micro-organisms are introduced into the deinking system by the introduction of the raw materials (waste paper and wood pulp) and by the process water. The addition of hydrogen peroxide and of other chemicals, 21~5~39 the extreme change of the pH value and the varying temperatures during the process act as stress factors on the bacteria which can lead to lysis of the bacteria.
Within the process water circulatlon, an equilibrium is adjusted between the rate of reproduction of the micro-organisms in the system, including the bacteria introduced by the introduced material and the lysing bacteria in the system. By means of the lysis of the bacteria, the enzyme-containing cell substance, which contains catalases and peroxidases, are given off into the deinking process water.
The influence of the enzyme catalase on the bleaching activity of hydrogen peroxide in the bleaching of waste paper and wood pulp is described in the literature. Thus, G. Galland and Y. Vernac, Progr. Pap.
Recycling, Vol. 2, pp. 20 - 30/1992, in their treatise concerning "Bleaching of recycled pulp", refer to - various causes for the decomposition of peroxide durin~
the bleaching process.
Besides traces of heavy metals, such as iron, manganese, copper and aluminium, the enzyme catalase is mentioned as the main cause of the decomposition of peroxide. Already in the case of catalase concentrations of 45 mg/litre, 60% of the hydrogen peroxide is decomposed within 10 minutes under the usual deinking bleaching conditions. The participation of catalase in the total rate of decomposition can be determined _ 21~5~39 by destroying the catalase by boiling and determining the rate of decomposition of the hydrogen peroxide before and after the boiling. The difference gives the proportion of catalase.
The following methods are discussed in order to eliminate the catalase:
1. The system is to be kept free of biological activity.
For the production of paper, besides the use of native wood pulps, to an increasing extent resource is had to recycled waste paper. The reuse of waste paper as a raw material source for the production of papers with a high degree of whiteness or brightness can only take place when, on the one hand, the coloured materials contained in the waste paper are substantially removed by rinsing out (in the following called deinking) and, on the other hand, the residues of coloured rnaterial are subjected to a chemical bleaching. Both procedures can be carried out in a common or in a multi-step process. The bleaching chemicals are used in order to destroy the chromophores present in the fibre materials, i.e. the coloured materials originating from the waste paper, as well as the dissolved and undissolved components of the printing colours. The bleaching can be carried out with oxidising and/or reducing chemicals.
Many processes for deinking and bleaching are described in the literature. A preferred process is the simult-aneous deinking and bleaching with hydrogen peroxide for waste paper and wood pulp.
The combined process is carried out, for example, with an agent of the following base composition:
2145g39 -sodium hydroxide 1.0 - 1.5% referred to atro material hydrogen peroxide 0.5 - 1.5% referred to atro material sodium silicate up to 4.0% referred to atro material complexing agent 0.1 - 0.4% referred to atro material soap 0.6 - 1.0% referred to atro material waste paper/ 0.9 - 2.0% referred to atro material wood pulp By "atro material" is to be understood the amount of the air-dried mixture of waste paper and wood pulp.
The statements of percentage are percentages by weight.
In practice, as carrier medium there is essentially reused in a cyclic process the water originating from the process. The deinking process water has, in general, a temperature of 30 to 60C.
In the first step of removing the coloured material, the pH reaches a value of 9.5 - 10.5.
The separation of fibres and printing colours is promoted by the alkaline medium. Hydrogen peroxide has proved to be an ideal bleaching agent since it bleaches especially effectively in an alkaline medium by activation of the hydroperoxide anion (see equation 1).
HO2 is the important molecule for the bleaching action Equation 1:
OH
H22 - HO2 + H+
During the process, as side reactions according to the following equation 2, there occurs a spontaneous dissociation of the hydrogen peroxide in the case of 2195~3~
`~ _ the presence of heavy metal ions or in the case of the presence of the enzyme catalase, as well as decomposition of the peroxide catalysed by peroxidases.
They reduce the degree of utilisation of the amount of hydrogen peroxide used and thereby influence the bleaching action. The result is an increased require-ment of hydrogen peroxide and aqueous sodium hydroxide solution.
Equation 2:
22 ) 2 2 2 It is known to mask the damaging action of heavy metal ions by the addition of complex formers, such as ethylenediamine-tetraacetic acid, pentetic acid (DTPA), polycarboxylic acids, for example citric acid, gluconic acid, polyacrylic acid, phosphonic acids and the like. These also serve simultaneously as flotation agents in the case of deinking (cf. DE 42 04 915 Al).
As natural products, waste paper and wood pulp are nutrient media for microbiological growth. Almost all micro-organisms which occur as a natural contamin-ation on and in waste paper and wood pulp synthesise, as cell-inherent enzy~les, catalases and various peroxidases.
Micro-organisms are introduced into the deinking system by the introduction of the raw materials (waste paper and wood pulp) and by the process water. The addition of hydrogen peroxide and of other chemicals, 21~5~39 the extreme change of the pH value and the varying temperatures during the process act as stress factors on the bacteria which can lead to lysis of the bacteria.
Within the process water circulatlon, an equilibrium is adjusted between the rate of reproduction of the micro-organisms in the system, including the bacteria introduced by the introduced material and the lysing bacteria in the system. By means of the lysis of the bacteria, the enzyme-containing cell substance, which contains catalases and peroxidases, are given off into the deinking process water.
The influence of the enzyme catalase on the bleaching activity of hydrogen peroxide in the bleaching of waste paper and wood pulp is described in the literature. Thus, G. Galland and Y. Vernac, Progr. Pap.
Recycling, Vol. 2, pp. 20 - 30/1992, in their treatise concerning "Bleaching of recycled pulp", refer to - various causes for the decomposition of peroxide durin~
the bleaching process.
Besides traces of heavy metals, such as iron, manganese, copper and aluminium, the enzyme catalase is mentioned as the main cause of the decomposition of peroxide. Already in the case of catalase concentrations of 45 mg/litre, 60% of the hydrogen peroxide is decomposed within 10 minutes under the usual deinking bleaching conditions. The participation of catalase in the total rate of decomposition can be determined _ 21~5~39 by destroying the catalase by boiling and determining the rate of decomposition of the hydrogen peroxide before and after the boiling. The difference gives the proportion of catalase.
The following methods are discussed in order to eliminate the catalase:
1. The system is to be kept free of biological activity.
2. The catalase is to be destroyed before the bleaching with:
heat treatment greater than 70C
sodium hypochlorite, concentration 0.3%
heat treatment greater than 70C
sodium hypochlorite, concentration 0.3%
3. acid wash (see V. Gehr et al., Das Papier, pp.
186-195/1993).
These methods are not satisfactory. To keep an open technical system free from contaminations is practically impossible since, especially with waste paper, micro-organisms are continuously introduced into the system. A heat treatment costs energy and is time-consuming and, in addition, damages the paper fibres.
The addition of hypochlorite is admittedly comparatively economic but also leads to a damaging of the fibres and to additional loading of the waste paper. The acid wash requires a separate process step and a subsequent expensive neutralisation, water-loading salts thereby again being formed.
Therefore, it is an object of the present invention to reduce the damaging influence of the 214~3~
hydrogen peroxide-decomposing catalases and peroxidases and thereby to avoid the above-mentioned disadvantages.
Thus, according to the present invention, there is provided a process for the oxidative bleaching of wood pulp and for the deinking of waste paper by means of hydrogen peroxide and a stabilising agent, wherein, as stabilising agent, there is used 2-oxo-2-(4-hydroxy-phenyl)-acethydroximic acid chloride ~N,4-dihydroxy-~-oxophenylethanimidoyl chloride) of the formula:
Cl C=N-OH
. HO ~ C
~ ~0 The stabilising agent can be used in a concent-ration of 0.002 - 2 g/kg of process water and preferably of 0.001 - 0.2 g/kg.
The stabilising agent can be added to the recycled process water.
The present invention also provides an agent for stabilising hydrogen peroxide-containing bleaching and deinking solutions for waste paper, wherein it contains 2-oxo-2-(4-hydroxyphenyl)-acethydroximic acid chloride (N,4-dihydroxy-~-oxophenylethanimidoyl chloride) as stabilising agent.
After the exclusion of the activity of the enzymes, by means of the use of 2-oxo-2-(4-hydroxy-phenyl)-acethydroximic acid chloride (hereinafter 21~5q39 called paraclox) or of mixtures containing this substance, the residual content of the hydrogen peroxide in the process is increased after the bleaching procedure. This can lead to a saving of considerable amounts of hydrogen peroxide while the bleaching actlon remains the same (whiteness, brightness) or to an increase of the degree of whiteness in the case of reduced amounts of peroxide.
The use of the stabiliser according to the present invention takes place in the bleaching deinking process, for example in the enzyme-containing inflow of the pulp water or in the pulper itself. In the case of all further bleaching processes for waste paper (after-bleaching) or wood pulp, the above-mentioned agent is added to the fibre diluting water or to the bleaching chemicals directly before the addition of the materials to be bleached.
Paraclox has previously been used in the paper industry in order to reduce the growth of slime-forming bacteria in the water circulations and in the waste water and thereby to prevent a blockage of the pipes.
It is surprising that this substance is suitable for the inactivation of free catalase andlor of peroxidase itself and not only to prevent the post-formation due to the growth of the micro-organisms.
The effectiveness of the agent used according to the present invention is shown by the following Examples.
Example 1 Measurement of the hydrogen peroxide-stabilising action of various antibacterially-actin~ molecules on the process water (deinking) of a paper factory.-The catalase test depends upon the measurement of the increase of the pressure in an airtight-closed vessel after the introduction of 0.1% hydrogen peroxide.
With increasing concentration of catalase in a sample, the pressure to be measured increases correspondingly.
The pressure is given as an electric signal in relative units (mV). The pressure increase is measured after 10 minutes.
active substance/con~Pntrationpressure in relative units (mV) ~400 ppm 2-oxo-2-(4-hyd,~y~henyl)- 0 2 ace~lydL~imic acid chloride 100 ppm 2-oxo-2-(4-hydl~y~henyl)- 0 5 acethydroximic acid chloride 10 ppm 2-oxo-2-(4-hydlu~y~henyl) 4 2 acethydroximic acid chloride 400 ppm 2,2-dibromo-3-nitrilo- > 9 0 propion ~Tn;~1~ (DBNPA) 400 ppm tetrakishydLo~y~ethyl- 9 0 phosph~n;l~ sulphate (THPS) > -400 ppm sodium m~n ~ thyldithio- 5 0 carbamate (metamsodium) 400 ppm m~n ~ thyl~n;l~ mono- > 9 0 methyl ~;th;oc~rbamate (MDTCMA) 400 ppm methylene bisthiocyanate (MBT) 6.2 comparison sample without additive9.8 (ppm = parts per million or g of substance/100 kg water) -2145~39 Example 2 Determination of the residual peroxide content after the addition of paraclox to different process water samples (deinkin~).
The measurement of the residual peroxide content took place by iodometric titration.
The initial peroxide content corresponds to 100%
(= 0.1% hydrogen peroxide (100%)!.
Process water 1 (clear filtrate) 0 min.~ 30 min. 60 min. 90 min. 120 min.
0 sample 100% 1.8% 0% 0% 0%
10 ppm paraclox 100% 55.4% 43.1% ~ 33.8% 26.9%
100 ppm paraclox 100% 9S.4% 87.7% 87.7% 86.1%
Process water 2 (drum 1) 0 min. 30 min. 60 min. 90 min. 120 min.
0 sample 100% 0% 0% 0% 0%
2 ppm paraclox 100% 3.6% 0% 0% 0%
20 ppm paraclox 100% 62.1% 56.8% 50.8% 47%
.
Example 3 Determination of the effect of paraclox on the degree of whiteness, the flotate, the ash and the residual peroxide content.
Experimental arrangement of the deinking experiment in the laboratory 214543~
Into 1 litre of water of 30dH (tap water) are introduced:
stabiliser 0.2%
waterglass 2.0%
aqueous sodium hydroxide solution 1.0%
soap 1.0%
peroxide 1.5%
and heated to 60C.
Into the pulper (2800 r.p.m.) are introduced 50 g of atro waste paper and the chemical solution is subse-quently introduced. The pulping time is 10 minutes.
After ending of the brushing out time, the paper slurry is shaken out into a glass beaker, stirred up with a lS commercially available ultrasonic disperser and the pH
value determined.
The pH value is 9.5 + 0.2. 100 ml are taken from the brushed out suspension and a sheet formed (degree of whiteness and brightness before the flotation).
The remaining fibre material is placed for 110 minutes in a waterbath with a temperature of 50C.
After the residence time, it is dispersed with a disperser for 1 minute at 10,000 r.p.m. The paper slurry is emptied into a flotation cell which is filled with water with a temperature of 50C. There is thereby adjusted a material density of 0.8% (pH value 8.5).
Air is introduced into the cell at a rate of 60 litres/
214543~
hour and the speed of stirring is 1000 r.p.m. The flotation time is 10 minutes, foam being skimmed off manually. After the flotation is ended, acidification is carried out with sulphuric acid to pH 5 and sheets 5 are formed.
The brightness and degree of whiteness are measured on the front and rear side and the average value determined.
Statement of the degree of whiteness:
R 457: reflection factor at 457 nm wavelength Y/C: standard type of light C/1931 Process water 1 was used. The statements of percentage refer to the commercial product and the residual peroxide was determined by a titration method.
before after ,flotate ash residual flotation flotation % , % peroxide 0 sample50.1 54.160.7 66.8 22.6 47.8 15.7 paraclox50.6 53.560.7 66.8 24.4 43.9 49.7 In the case of values otherwise remaining the same, the residual peroxide content shows a concentration dependency in the experimental batch.
0 sample 15.7% residual peroxide paraclox 0.02% 21.4% "
paraclox 0.04% 28.5% "
paraclox 0.08% 49.7% "
21g5939 Example 4 Determination of the influence of DTPA-containing stabiliser (heavy metal complexing) on the rate of decomposition of peroxide in comparison with the action of catalase-inhibiting substances.
As sample, there was used process water 3 and worked up analogously to Example 1. After the addition of 0.1% hydrogen peroxide (referred to 100% hydrogen peroxide), there was measured the pressure increase in relative pressure units (in mV) after 10 minutes. The measurement took place at ambient temperature.
0 sample 9.8 paraclox 400 ppm 0.2 (referred to process water volume) 15 DTPS stabiliser 2000 ppm 5.9 (referred to process water volume) Example 5 Investigation of the action of paraclox, glutaraldehyde and chlorine bleach lye on the pure enzyme catalase.
Method according to Biurett Chemicals:
phosphate buffer 0.05M, pH 7.0 (K2HP04: 8.7 g/l;
KH2P04: 6.8 g/l) enzyme catalase (No. C10 Sigma catalogue) substrate hydrogen peroxide (30%).
l. Enzyme solution (solution A):
Dissolve catalase in 0.05M phosphate buffer.
"- 214543~
Concentration: 50 sigma units per ml of buffer.
1000 ml solution A contains 50,000 sigma units 1600 units = 1 mg solid material (C10 catalase) 50,000 units = 31.25 mg of solid material (C10 catalase) The en~yme solution must be used directly.
2. Substrate solution (= solution B) Dissolve 0.1 ml 30% hydrogen peroxide in 50 ml of 0.05M
phosphate buffer (control) cr in 50 ml phosphate buffer which contains the stabiliser (substrate). Measure the absorption at 240 nm. The result must lie between 0.550 and 0.520. Possibly dilute the solution or add more hydrogen peroxide thereto.
3. Measurement 2.9 ml of solution B are placed in a quartz cuvette and subsequently mixed with 0.1 ml of solution A. The absorption at 240 nm should, at the beginning of the measurement, amount to approximately 0.450. The time needed for the decrease of the absorption at 240 nm from 0.450 to 0.400 is determined.
This time corresponds to the conversion of 3.45 ~mol hydrogen peroxide in 3 ml of sample volume.
Result:
Activity (sigma units total) = 3.45: time (minutes calculating back to active sigma units 1 sigma unit reacts 1.0 ~mol hydrogen peroxide per minute (at pH 7.0; 25C).
~ 21~5439 paraclox glutaraldehyde 0 sample 0% inhibition 0 sample 0% inhibition pOar2appmx 0% inhibition glutar- 6% inhibition 50.5 ppm paraclox 16% inhibition glutar- 9% inhibition 1 ppm aldehyde 2.5 ppm paraclox 63% inhibition glutar- 11% inhibition 2 ppm aldehyde 5 ppm Sodium hypochlorite reacts in solution B with hydrogen peroxide with decomposition before ca~alase can be added.
Example 6 Catalase-dependent action of paraclox on the stability of the hydrogen peroxide in a flotation experiment In the case of this experiment, working was analogous to Example 3 but tap water was used instead of process water. The influence of catalase (due to the substantial absence of bacteria) is thereby distinctly reduced. At the same time, in the case of this experiment, the addition of waterglass as stabiliser is omitted.
214~439 wh;tenPss flotate ash residual after peroxide flotation S 0 sample 54.6 58.. 2 16.770 46.5% 15%
paraclox 0.02% 55.4 59.8 20.7% . 50.2% 34.0%
paraclox 0.04% 55.8 60.5 18.7% 51.0% 41.0%
paraclox 0.08% 55.0 58.8 23.3% 48.4% 52.4%
The results show for paraclox a very good stabilising action on the peroxide. This action is not to be attributed exclusively to the inhibition of the catalase and depends upon a side effect which has hitherto not been elucidated.
186-195/1993).
These methods are not satisfactory. To keep an open technical system free from contaminations is practically impossible since, especially with waste paper, micro-organisms are continuously introduced into the system. A heat treatment costs energy and is time-consuming and, in addition, damages the paper fibres.
The addition of hypochlorite is admittedly comparatively economic but also leads to a damaging of the fibres and to additional loading of the waste paper. The acid wash requires a separate process step and a subsequent expensive neutralisation, water-loading salts thereby again being formed.
Therefore, it is an object of the present invention to reduce the damaging influence of the 214~3~
hydrogen peroxide-decomposing catalases and peroxidases and thereby to avoid the above-mentioned disadvantages.
Thus, according to the present invention, there is provided a process for the oxidative bleaching of wood pulp and for the deinking of waste paper by means of hydrogen peroxide and a stabilising agent, wherein, as stabilising agent, there is used 2-oxo-2-(4-hydroxy-phenyl)-acethydroximic acid chloride ~N,4-dihydroxy-~-oxophenylethanimidoyl chloride) of the formula:
Cl C=N-OH
. HO ~ C
~ ~0 The stabilising agent can be used in a concent-ration of 0.002 - 2 g/kg of process water and preferably of 0.001 - 0.2 g/kg.
The stabilising agent can be added to the recycled process water.
The present invention also provides an agent for stabilising hydrogen peroxide-containing bleaching and deinking solutions for waste paper, wherein it contains 2-oxo-2-(4-hydroxyphenyl)-acethydroximic acid chloride (N,4-dihydroxy-~-oxophenylethanimidoyl chloride) as stabilising agent.
After the exclusion of the activity of the enzymes, by means of the use of 2-oxo-2-(4-hydroxy-phenyl)-acethydroximic acid chloride (hereinafter 21~5q39 called paraclox) or of mixtures containing this substance, the residual content of the hydrogen peroxide in the process is increased after the bleaching procedure. This can lead to a saving of considerable amounts of hydrogen peroxide while the bleaching actlon remains the same (whiteness, brightness) or to an increase of the degree of whiteness in the case of reduced amounts of peroxide.
The use of the stabiliser according to the present invention takes place in the bleaching deinking process, for example in the enzyme-containing inflow of the pulp water or in the pulper itself. In the case of all further bleaching processes for waste paper (after-bleaching) or wood pulp, the above-mentioned agent is added to the fibre diluting water or to the bleaching chemicals directly before the addition of the materials to be bleached.
Paraclox has previously been used in the paper industry in order to reduce the growth of slime-forming bacteria in the water circulations and in the waste water and thereby to prevent a blockage of the pipes.
It is surprising that this substance is suitable for the inactivation of free catalase andlor of peroxidase itself and not only to prevent the post-formation due to the growth of the micro-organisms.
The effectiveness of the agent used according to the present invention is shown by the following Examples.
Example 1 Measurement of the hydrogen peroxide-stabilising action of various antibacterially-actin~ molecules on the process water (deinking) of a paper factory.-The catalase test depends upon the measurement of the increase of the pressure in an airtight-closed vessel after the introduction of 0.1% hydrogen peroxide.
With increasing concentration of catalase in a sample, the pressure to be measured increases correspondingly.
The pressure is given as an electric signal in relative units (mV). The pressure increase is measured after 10 minutes.
active substance/con~Pntrationpressure in relative units (mV) ~400 ppm 2-oxo-2-(4-hyd,~y~henyl)- 0 2 ace~lydL~imic acid chloride 100 ppm 2-oxo-2-(4-hydl~y~henyl)- 0 5 acethydroximic acid chloride 10 ppm 2-oxo-2-(4-hydlu~y~henyl) 4 2 acethydroximic acid chloride 400 ppm 2,2-dibromo-3-nitrilo- > 9 0 propion ~Tn;~1~ (DBNPA) 400 ppm tetrakishydLo~y~ethyl- 9 0 phosph~n;l~ sulphate (THPS) > -400 ppm sodium m~n ~ thyldithio- 5 0 carbamate (metamsodium) 400 ppm m~n ~ thyl~n;l~ mono- > 9 0 methyl ~;th;oc~rbamate (MDTCMA) 400 ppm methylene bisthiocyanate (MBT) 6.2 comparison sample without additive9.8 (ppm = parts per million or g of substance/100 kg water) -2145~39 Example 2 Determination of the residual peroxide content after the addition of paraclox to different process water samples (deinkin~).
The measurement of the residual peroxide content took place by iodometric titration.
The initial peroxide content corresponds to 100%
(= 0.1% hydrogen peroxide (100%)!.
Process water 1 (clear filtrate) 0 min.~ 30 min. 60 min. 90 min. 120 min.
0 sample 100% 1.8% 0% 0% 0%
10 ppm paraclox 100% 55.4% 43.1% ~ 33.8% 26.9%
100 ppm paraclox 100% 9S.4% 87.7% 87.7% 86.1%
Process water 2 (drum 1) 0 min. 30 min. 60 min. 90 min. 120 min.
0 sample 100% 0% 0% 0% 0%
2 ppm paraclox 100% 3.6% 0% 0% 0%
20 ppm paraclox 100% 62.1% 56.8% 50.8% 47%
.
Example 3 Determination of the effect of paraclox on the degree of whiteness, the flotate, the ash and the residual peroxide content.
Experimental arrangement of the deinking experiment in the laboratory 214543~
Into 1 litre of water of 30dH (tap water) are introduced:
stabiliser 0.2%
waterglass 2.0%
aqueous sodium hydroxide solution 1.0%
soap 1.0%
peroxide 1.5%
and heated to 60C.
Into the pulper (2800 r.p.m.) are introduced 50 g of atro waste paper and the chemical solution is subse-quently introduced. The pulping time is 10 minutes.
After ending of the brushing out time, the paper slurry is shaken out into a glass beaker, stirred up with a lS commercially available ultrasonic disperser and the pH
value determined.
The pH value is 9.5 + 0.2. 100 ml are taken from the brushed out suspension and a sheet formed (degree of whiteness and brightness before the flotation).
The remaining fibre material is placed for 110 minutes in a waterbath with a temperature of 50C.
After the residence time, it is dispersed with a disperser for 1 minute at 10,000 r.p.m. The paper slurry is emptied into a flotation cell which is filled with water with a temperature of 50C. There is thereby adjusted a material density of 0.8% (pH value 8.5).
Air is introduced into the cell at a rate of 60 litres/
214543~
hour and the speed of stirring is 1000 r.p.m. The flotation time is 10 minutes, foam being skimmed off manually. After the flotation is ended, acidification is carried out with sulphuric acid to pH 5 and sheets 5 are formed.
The brightness and degree of whiteness are measured on the front and rear side and the average value determined.
Statement of the degree of whiteness:
R 457: reflection factor at 457 nm wavelength Y/C: standard type of light C/1931 Process water 1 was used. The statements of percentage refer to the commercial product and the residual peroxide was determined by a titration method.
before after ,flotate ash residual flotation flotation % , % peroxide 0 sample50.1 54.160.7 66.8 22.6 47.8 15.7 paraclox50.6 53.560.7 66.8 24.4 43.9 49.7 In the case of values otherwise remaining the same, the residual peroxide content shows a concentration dependency in the experimental batch.
0 sample 15.7% residual peroxide paraclox 0.02% 21.4% "
paraclox 0.04% 28.5% "
paraclox 0.08% 49.7% "
21g5939 Example 4 Determination of the influence of DTPA-containing stabiliser (heavy metal complexing) on the rate of decomposition of peroxide in comparison with the action of catalase-inhibiting substances.
As sample, there was used process water 3 and worked up analogously to Example 1. After the addition of 0.1% hydrogen peroxide (referred to 100% hydrogen peroxide), there was measured the pressure increase in relative pressure units (in mV) after 10 minutes. The measurement took place at ambient temperature.
0 sample 9.8 paraclox 400 ppm 0.2 (referred to process water volume) 15 DTPS stabiliser 2000 ppm 5.9 (referred to process water volume) Example 5 Investigation of the action of paraclox, glutaraldehyde and chlorine bleach lye on the pure enzyme catalase.
Method according to Biurett Chemicals:
phosphate buffer 0.05M, pH 7.0 (K2HP04: 8.7 g/l;
KH2P04: 6.8 g/l) enzyme catalase (No. C10 Sigma catalogue) substrate hydrogen peroxide (30%).
l. Enzyme solution (solution A):
Dissolve catalase in 0.05M phosphate buffer.
"- 214543~
Concentration: 50 sigma units per ml of buffer.
1000 ml solution A contains 50,000 sigma units 1600 units = 1 mg solid material (C10 catalase) 50,000 units = 31.25 mg of solid material (C10 catalase) The en~yme solution must be used directly.
2. Substrate solution (= solution B) Dissolve 0.1 ml 30% hydrogen peroxide in 50 ml of 0.05M
phosphate buffer (control) cr in 50 ml phosphate buffer which contains the stabiliser (substrate). Measure the absorption at 240 nm. The result must lie between 0.550 and 0.520. Possibly dilute the solution or add more hydrogen peroxide thereto.
3. Measurement 2.9 ml of solution B are placed in a quartz cuvette and subsequently mixed with 0.1 ml of solution A. The absorption at 240 nm should, at the beginning of the measurement, amount to approximately 0.450. The time needed for the decrease of the absorption at 240 nm from 0.450 to 0.400 is determined.
This time corresponds to the conversion of 3.45 ~mol hydrogen peroxide in 3 ml of sample volume.
Result:
Activity (sigma units total) = 3.45: time (minutes calculating back to active sigma units 1 sigma unit reacts 1.0 ~mol hydrogen peroxide per minute (at pH 7.0; 25C).
~ 21~5439 paraclox glutaraldehyde 0 sample 0% inhibition 0 sample 0% inhibition pOar2appmx 0% inhibition glutar- 6% inhibition 50.5 ppm paraclox 16% inhibition glutar- 9% inhibition 1 ppm aldehyde 2.5 ppm paraclox 63% inhibition glutar- 11% inhibition 2 ppm aldehyde 5 ppm Sodium hypochlorite reacts in solution B with hydrogen peroxide with decomposition before ca~alase can be added.
Example 6 Catalase-dependent action of paraclox on the stability of the hydrogen peroxide in a flotation experiment In the case of this experiment, working was analogous to Example 3 but tap water was used instead of process water. The influence of catalase (due to the substantial absence of bacteria) is thereby distinctly reduced. At the same time, in the case of this experiment, the addition of waterglass as stabiliser is omitted.
214~439 wh;tenPss flotate ash residual after peroxide flotation S 0 sample 54.6 58.. 2 16.770 46.5% 15%
paraclox 0.02% 55.4 59.8 20.7% . 50.2% 34.0%
paraclox 0.04% 55.8 60.5 18.7% 51.0% 41.0%
paraclox 0.08% 55.0 58.8 23.3% 48.4% 52.4%
The results show for paraclox a very good stabilising action on the peroxide. This action is not to be attributed exclusively to the inhibition of the catalase and depends upon a side effect which has hitherto not been elucidated.
Claims (8)
1. Process for the oxidative bleaching of wood pulp and for deinking waste paper by means of hydrogen peroxide and a stabilising agent, wherein, as stabilising agent, there is used 2-oxo-2-(4-hydroxyphenyl)-acethydroximic acid chloride (N,4-dihydroxy-oxophenylethanimidoyl chloride) of the formula:-
2. Process according to claim 1, wherein the stabilising agent is used in a concentration of 0.002 to 2 g/kg of process water.
3. Process according to claim 2, wherein the stabilising agent is used in a concentration of 0.001 to 0.2 g/kg of process water.
4. Process according to any of the preceding claims, wherein the stabilising agent is added to the recycled process water.
5. Process according to claim 1 for the oxidative bleaching of wood pulp and for deinking waste paper, substantially as hereinbefore described and exemplified.
6. Wood pulp and waste paper, whenever treated by the process according to any of claims 1 to 5.
7. Agent for stabilising hydrogen peroxide-containing bleaching and deinking solutions for waste paper, wherein it contains 2-oxo-2-(4-hydroxyphenyl)-acethydroximic acid chloride (N,4-dihydroxy-.alpha.-phenylethanimidoyl chloride).
8. Agent according to claim 1 for stabilising hydrogen peroxide-containing bleaching and deinking solutions for waste paper, substantially as hereinbefore described and exemplified.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4410663A DE4410663C1 (en) | 1994-03-26 | 1994-03-26 | Process and compositions for the oxidative bleaching of wood pulp and for the deinking of waste paper |
| DEP4410663.7 | 1994-03-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2145439A1 true CA2145439A1 (en) | 1995-09-27 |
Family
ID=6514017
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2145439 Abandoned CA2145439A1 (en) | 1994-03-26 | 1995-03-24 | Process and agent for the oxidative bleaching of wood pulp and for deinking waste paper |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US5607544A (en) |
| JP (1) | JPH07268791A (en) |
| KR (1) | KR950032883A (en) |
| CA (1) | CA2145439A1 (en) |
| DE (1) | DE4410663C1 (en) |
| FI (1) | FI951423A (en) |
| GB (1) | GB2287724B (en) |
| NL (1) | NL9500377A (en) |
| SE (1) | SE9500928L (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6001218A (en) | 1994-06-29 | 1999-12-14 | Kimberly-Clark Worldwide, Inc. | Production of soft paper products from old newspaper |
| US6074527A (en) | 1994-06-29 | 2000-06-13 | Kimberly-Clark Worldwide, Inc. | Production of soft paper products from coarse cellulosic fibers |
| US5582681A (en) | 1994-06-29 | 1996-12-10 | Kimberly-Clark Corporation | Production of soft paper products from old newspaper |
| US6296736B1 (en) | 1997-10-30 | 2001-10-02 | Kimberly-Clark Worldwide, Inc. | Process for modifying pulp from recycled newspapers |
| US6387210B1 (en) | 1998-09-30 | 2002-05-14 | Kimberly-Clark Worldwide, Inc. | Method of making sanitary paper product from coarse fibers |
| GB0001417D0 (en) * | 2000-01-22 | 2000-03-08 | Albright & Wilson Uk Ltd | Bleaching pulp |
| AU2001275432A1 (en) * | 2000-06-08 | 2001-12-17 | Lonza Inc. | Aldehyde donors for stabilizing peroxides in papermaking applications |
| US7052614B2 (en) * | 2001-08-06 | 2006-05-30 | A.Y. Laboratories Ltd. | Control of development of biofilms in industrial process water |
| CA2514798C (en) * | 2003-02-05 | 2009-06-16 | Pulp And Paper Research Institute Of Canada | Bleaching and brightness stabilization of lignocellulosic materials with water-soluble phosphines or phosphonium compounds |
| JP2010236166A (en) * | 2009-03-31 | 2010-10-21 | Nippon Paper Industries Co Ltd | Method for producing deinked pulp |
| CN103374848B (en) * | 2012-04-28 | 2016-03-02 | 上海韬鸿化工科技有限公司 | The environmental protection method for bleaching of a kind of environmental protection bleaching liquid and natural fabric |
| CN105088854A (en) * | 2015-08-13 | 2015-11-25 | 合肥龙发包装有限公司 | Environmentally-friendly package paper |
| EP3751050A1 (en) * | 2019-06-13 | 2020-12-16 | Wöllner GmbH | Use of probiotic bacteria for inhibiting the decomposition of peroxide in the deinking of recycled fiber pulp |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USRE26009E (en) * | 1966-05-03 | Xcx cii ciijbr | ||
| US3790687A (en) * | 1970-02-24 | 1974-02-05 | Roussel Uclaf | Methods of combatting fungi and bacteria using substituted-alpha-isonitroso-acetophenones |
| LU74434A1 (en) * | 1976-02-25 | 1977-09-12 | ||
| FR2482989A1 (en) * | 1980-05-22 | 1981-11-27 | Interox | PROCESS FOR THE REGENERATION OF OLD PAPERS |
| DE3816943A1 (en) * | 1988-05-18 | 1989-11-30 | Nixdorf Computer Ag | METHOD FOR CHECKING SHEET MATERIAL |
| JPH02311404A (en) * | 1989-05-24 | 1990-12-27 | Hakutou Kagaku Kk | Germicide composition for industry |
| DE4204915C2 (en) * | 1992-02-19 | 1995-09-28 | Benckiser Knapsack Ladenburg | Process for recycling waste paper |
| GB2269191A (en) * | 1992-07-29 | 1994-02-02 | Solvay Interox Ltd | Method of treating aqueous process liquors |
-
1994
- 1994-03-26 DE DE4410663A patent/DE4410663C1/en not_active Expired - Fee Related
-
1995
- 1995-02-24 NL NL9500377A patent/NL9500377A/en active Search and Examination
- 1995-03-16 GB GB9505332A patent/GB2287724B/en not_active Expired - Fee Related
- 1995-03-16 SE SE9500928A patent/SE9500928L/en not_active Application Discontinuation
- 1995-03-17 KR KR1019950005509A patent/KR950032883A/en not_active Application Discontinuation
- 1995-03-24 CA CA 2145439 patent/CA2145439A1/en not_active Abandoned
- 1995-03-24 FI FI951423A patent/FI951423A/en unknown
- 1995-03-27 JP JP6842695A patent/JPH07268791A/en active Pending
- 1995-03-27 US US08/411,148 patent/US5607544A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE4410663C1 (en) | 1995-08-17 |
| GB9505332D0 (en) | 1995-05-03 |
| US5607544A (en) | 1997-03-04 |
| NL9500377A (en) | 1995-11-01 |
| SE9500928D0 (en) | 1995-03-16 |
| JPH07268791A (en) | 1995-10-17 |
| KR950032883A (en) | 1995-12-22 |
| GB2287724B (en) | 1997-09-17 |
| FI951423A0 (en) | 1995-03-24 |
| GB2287724A (en) | 1995-09-27 |
| SE9500928L (en) | 1995-09-27 |
| FI951423A (en) | 1995-09-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5607544A (en) | Process and agent for the oxidative bleaching of wood pulp and for deinking waste paper | |
| US4381969A (en) | Process for the regeneration of waste paper | |
| US5885412A (en) | Inhibition of hydrogen peroxide decomposing enzymes during bleaching of cellulose fibers | |
| US5618385A (en) | Method of peroxide bleaching of pulp using a peroxide decomposing inactivator | |
| US4356058A (en) | Process for the reprocessing of papers | |
| US5529660A (en) | Method of reducing fluorescence in deinked pulp by treating pulp with ozone and a bleaching agent | |
| USH479H (en) | Wood pulp bleaching process | |
| RU2066720C1 (en) | Method for processing of waste paper | |
| JPH03199477A (en) | Method for carrying out regeneration treatment of waste paper | |
| US3709779A (en) | Bleaching of mechanical pulps with hydrosulfite in the presence of an alkali metal silikate | |
| CA1333650C (en) | Peroxide bleaching method | |
| US6217706B1 (en) | Method of de-inking paper and other cellulosic materials | |
| US4244777A (en) | Bleaching stilbene yellow dyed wood pulp | |
| CA2127967A1 (en) | Method for bleaching lignocellulose-containing fibres | |
| JPH0835188A (en) | Method for deinking and bleaching waste paper | |
| JP2010236166A (en) | Method for producing deinked pulp | |
| US20050145349A1 (en) | Method of de-inking paper and other cellulosic materials | |
| JPH05148783A (en) | Method for pulping waste paper of heat-sensitive recording chart | |
| JP2005517834A (en) | Ozone treatment method for waste paper | |
| EP1031657A1 (en) | A method for bleaching secondary fibres | |
| Renders et al. | Eucepa Symposium “Recycling “95", Manchester, UK, October 1995 | |
| JPH06287879A (en) | Method for recycling colored waste paper and paper using recycled pulp of waste paper | |
| JPH062293A (en) | Quality improvement for reclaimed pulp from woodfree waste paper | |
| JPH04308292A (en) | Pulp-bleaching of deinked pulp-containing craft pulp | |
| JPH08199489A (en) | Deinking of printed old paper |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |