KR19980025354A - Deinking Method of Wasteland by Alkalophilic Wood Degrading Enzyme - Google Patents

Abstract

(Purpose) Usually, the papermaking process uses water of pH 9 ~ 11, which eliminates the trouble of replacing the water of the papermaking process in order to desorb with acidic enzymes, and the fiber of the highland is not rigid and is used in the acidic region. An object of the present invention is to provide a method for decontamination that significantly reduces the amount of decontamination aid.

(Composition) Alkaline wood degrading enzyme is added in alkaline water of waste paper of the waste paper to remove ink particles to desorb the waste paper.

Description

Deinking Method of Wasteland by Alkalophilic Wood Degrading Enzyme

The present invention relates to a method for preparing a paper pulp for papermaking by removing ink from newspaper papers and woody paper waste paper using alkalophilic wood degrading enzyme secreted by basidiomycetes.

De-inking is a process of removing dirt and foreign substances mainly on ink from printed paper, that is, newspaper, magazine, copy paper, and the like, and regenerating the original paper pulp.

The chemicals used in the conventional deinking process include caustic soda, sodium silicate, metal ion chelating agents, and foamable foams that float with air to the surface of the pulp slurry while cleaning and dispersing ink particles desorbed from hydrogen peroxide and pulp fibers. Surfactant and the like.

Typical surfactants include sodium and potassium salts of linear fatty acids, chain alkylbenzenesulfonates, olefin sulfonates, aliphatic alcohols, alkyl phenols, fatty acid ethylene oxide or propylene oxide adducts.

The problem that occurs when these surfactants are used in the deinking process is the poor degradability of the surfactant in the trouble and drainage treatment due to the excessive bubbles generated in the piping or paper making process for the transfer of pulp in the deinking and papermaking process. The burden of wastewater treatment can be pointed out.

In particular, in the defrosting process due to flotation, ink is used to make large particles of mass, and a collecting agent is used to attach them to the bubble surface.The problem of the flotation process using fatty acid collecting agent is a raw material transportation line and papermaking in the post process. Pitch and scale adhesion in a process are mentioned.

In addition, hydrogen peroxide is treated to improve the whiteness of the recycled pulp. At this time, a large amount of caustic soda and sodium silicate are added together with hydrogen peroxide. However, newspaper and white paper generated by the advancement of modern printing and copying technologies are printed by Xerox, laser, offset, ink jet, etc., and it is very difficult to reproduce by the conventional method. In order to solve this problem, deinking methods using commercial enzymes as a relatively new technique have been studied and introduced into some processes.

However, the above-mentioned enzymes are acidic enzymes centered on general acidic cellulase, and it is pointed out that the optimum pH is weakly acidic of 5-7, which makes it difficult to introduce them into the deinking process. In other words, since the normal papermaking process is operated as water of pH 9 ~ 10, the water of the papermaking process needs to be replaced in order to use the enzyme. In addition, since the highland fiber is stiffened in the acidic water, a lot of power is used in the high island sea island. Consumed.

Also, in papermaking from recycled pulp, fillers such as calcium carbonate should be added to increase the paper's opacity, smoothness, printability, etc., but since they are easily dissolved in acid, they may be used for deinking by acid cellulose. Since a large amount of filler must be added, the cost burden is increased.

It can be degreased with enzyme even at pH 9-10, and the papermaking process uses water of pH 9-10. In order to degrease with acidic enzyme, the trouble of replacing the water of papermaking process is eliminated. It is an object of the present invention to solve the problem that power consumption is not stiff and consumes a lot of sea islands, and to provide a deoiling method that significantly reduces the amount of deinking aid used in an acidic region.

In order to solve the above problems, it is characterized by removing the ink particles by the addition of alkaline alkaline wood degrading enzyme in alkaline water of the paper stock of the high land.

Best Mode for Carrying Out the Invention

The deinking method according to the present invention does not require a large amount of alkali, sodium silicate, and hydrogen peroxide, such as a deinking method by a chemical such as a conventional surfactant, and replaces water or other papermaking in the papermaking process as in the method of acidic cellulase. It is an advanced method that can solve problems such as decomposition of additives (for example, calcium carbonate) required for.

In other words, it is a deinking method that can improve the disadvantages of chemical deodorization method and biological (conventional commercial enzyme) deinking method and take advantage of both processes.

The method of the present invention is described in detail below.

Production of Alkaline Enzymes

Optimal strains were evaluated by examining the growth status and enzyme protein secretion capacity of 12 species with different carbon source, nitrogen source and trace element adjusted to pH 9 from 40 strains of wild mushrooms collected from the wild and strain storage organs. Was selected. The selected strains were incubated for 5 days in a liquid medium containing a woody carbon source, followed by centrifugation, and the supernatant was concentrated and used as an alkalophilic wood degrading enzyme solution.

The crude enzyme solution obtained by the above method exhibited high activity in the optimum reaction temperature of 50 ° C. and the optimum pH in the range of pH 5 and pH 9 as shown in FIG. 1. This indicates that the enzyme secreted by the strain contains two kinds of wood lyases that act in acidic and alkaline conditions.

The enzyme activity of the crude enzyme solution at pH 9 was 0.1 U / mg.protein of CMCase, 0.3U / mg.protein of Fpase, and 0.3U / mg.protein of xylanase.

Figure 1. Degradation Activity of CMC by pH of Coenzyme Solution

Newspaper or woodfree paper is dissolved in a conventional pulper (concentration 4-8%) by adjusting the water temperature from room temperature to 60 ° C and pH 7-11 with dilute NaOH solution.

The addition of enzyme quantifies the protein concentration in the crude enzyme solution and adds it as 0.05-1% to the dry weight of used paper as a protein.

Compared with the conventional method of caustic soda and surfactant and the method of acidic cellulase, when desalination by addition of the enzyme above pH 9, the time of decoction by the swelling of the fiber by alkali and the biological action of the enzyme Can be shortened and the peeling of ink particles is promoted. In particular, it can be confirmed that the detachment of the ink particles embedded in the paper waste paper is promoted. In addition, according to the present method, even if the amount of all kinds of deinking aids used in the alkaline region is drastically reduced, the same effects as in the conventional method can be obtained, thereby solving the secondary problem caused by the chemical agent. In addition, the problem of the deinking process by acidic cellulase, that is, in the water exchange or sea island process. It can solve the problem of consuming a lot of energy and can obtain mechanically better quality recycled pulp for papermaking.

Example

While preferred embodiments of this invention have been described by way of example, structural changes and other examples can of course be carried out without departing from any of the spirit or scope of the invention.

Example 1

The silence of a newspaper notice

After tearing the devotion paper by hand about 2 × 2cm, mix it well and make it as high supporting material to make 4% of paper stock, and fill it with water of 50 ℃ adjusted to pH 9 with NaOH solution, and then give 0.5% of alkalinity to high paper weight. It was immersed for 10 minutes by the addition of wood degrading enzyme solution, and then desalted for 5 minutes. After digestion, the waste paper slurry was diluted to 1% to remove airborne ink particles while injecting air on a floater. The whiteness and mechanical strength of the recycled pulp fibers obtained by the flotation process were measured. The results are shown in Table 1.

Example 2

It carried out similarly to Example 1 except having changed this to pH 10 instead of pH9 in Example 1.

Example 3

In Example 1, it carried out similarly to Example 1 except having set it to pH 11 instead of pH9.

Comparative Example 1

In order to compare with conventional chemical deinking method, devoted paper was torn and mixed to about 2cm × 2cm to make paper stock 4%, 1.0% NaOH, 0.3% H ₂ O ₂ , 3% Sodium silicate (water glass) and 0.8% ZERFAx MT-90 (fatty acid soap) were added, and the same procedure as in Example 1 was carried out.

Comparative Example 2

In Example 1, instead of pH 9, it was replaced with cellosoft (Novo) instead of alkaline wood degrading enzyme, and 10 minutes of sea islands (5 minutes of sea islands were not completely desolated because The process was carried out in the same manner as in Example 1 except that the solution was completely removed.

Comparative Example 3

Comparative Example 2 was carried out in the same manner as in Comparative Example 1 except that Pergalase (Novo) was substituted for Cellulsoft.

As can be seen from Table 1, the pulp desorbed by the present method exhibits the highest whiteness at pH 10, which is almost comparable to desalination by acidic cellulase for 10 minutes in acidic water. At the same time, NaOH consumed to adjust the pH to 10 is about 0.3% of the pulp weight, and the effect of alkaline wood degrading enzymes can reach the inside of the high fat fiber by the swelling effect of NaOH without affecting the sulfur change of the pulp. It seems to be.

Table 1. Comparison of Properties of Pulp Recycled by the Method of the Present Invention and the Conventional Method

Sea Island Time (minutes) brightness(%) Tensile Coefficient (Nm / g) Rupture factor (kpa · ㎡ / g) Example 1 (pH 9) Example 2 (pH 10) Example 3 (pH 11) Comparative Example 1 Comparative Example 2 (pH 7.0) Comparative Example 3 (pH 7.0) 5 5 5 5 10 10 48.3 49.2 46.0 45.4 49.5 49.0 29.3 30.1 29.7 29.8 28.6 28.8 2.9 3.0 2.8 2.8 2.7 2.7

On the other hand, it was confirmed that the fatty acid soap caused the yellowness of the fiber by 1% NaOH, resulting in a decrease in whiteness, and the acidic cellulase, which had a longer time-consuming defect in the high island sea island.

Example 4

Quilting of Great White Hill

The copy paper copied by laser printing was processed in the same manner as in Example 1. In the case of algae highland, the sea island time was 20 minutes. As can be seen from Table 2, it can be seen that the method according to the present invention produces much improved recycled pulp in comparison with the conventional method in terms of the whiteness, the number of remaining ink and the strength of recycled waste paper pulp.

Table 2. Property comparison of pulp recycled by the method of the present invention and the conventional method

brightness(%) Dirt (water / area) Tensile Coefficient (Nm / g) Example 2 (pH 10) Comparative Example 1 Comparative Example 3 83.2 79.0 80.3 840 2930 1827 34.6 28.4 30.5

Dealing with alkalescent enzymes does not require replacement of water in the removal process, and because the fibers of the highland are not rigid, less power consumption is required, and the amount of deinking aids used in the alkaline region is significantly reduced.

Claims (4)

A method for denitrifying and reclaiming waste paper by alkaline alkaline wood degrading enzyme, characterized by adding an alkaline alkaline wood degrading enzyme to remove ink particles in alkaline water of a waste paper. The method for denitrification of highland by alkalescent wood degrading enzymes according to claim 1, wherein the ink mushroom is a cellulase or xylase that is cultured and secreted on a pH 9 medium. The method for denitrification of waste paper by alkalophilic wood degrading enzyme according to claim 1 or 2, characterized in that a alkaline alkaline wood degrading enzyme is added in the range of 0.05% to 2% based on the dry weight of the waste paper. The method of claim 1, wherein the alkaline water has a pH range of 8 to 10.