Compound enzyme preparation for waste paper deinking, enzymatic deinking method and application

Abstract

The invention belongs to the technical field of waste paper pulp deinking, and particularly relates to a compound enzyme preparation for waste paper deinking, an enzymatic deinking method and application. The compound enzyme preparation provided by the invention comprises lipase, cellulase, amylase and xylanase, can generate an excellent deinking effect at a lower dosage, and is especially suitable for deinking waste newspaper. The enzymatic deinking method provided by the invention comprises the steps of pulping, enzyme treatment and flotation, does not need to use a large amount of chemicals, and can effectively reduce wastewater discharge in production engineering compared with chemical treatment. By utilizing the compound enzyme preparation and the enzymatic deinking method, the problem of sewage treatment in conventional chemical deinking can be solved, the problems that when waste newspaper is treated by enzymatic deinking, the using amount of enzyme and a surfactant is large, an enzyme activator needs to be added or other paper needs to be added and the like can be solved, and the compound enzyme preparation and the enzymatic deinking method have a good application prospect in waste newspaper deinking.

Description

Technical Field

[0001] The invention belongs to the technical field of waste paper pulp deinking, and in particular relates to a composite enzyme preparation for waste paper deinking and an enzymatic deinking method and application. Background Art

[0003] Recycling waste paper can significantly reduce tree felling, save raw materials and water resources, and reduce environmental pollution caused by waste paper landfill and incineration. It is an important measure to protect the environment and promote sustainable development.

[0004] One of the key links in the recycling of waste paper is to deink the waste paper. The current method for deinking waste paper is mainly chemical deinking. Chemical deinking requires the use of a large amount of chemicals, which will cause serious environmental pollution and increase the difficulty and cost of wastewater treatment; it may also produce harmful by-products, posing a potential threat to the ecological environment. Therefore, environmentally friendly enzymatic deinking has become a hot spot and main development direction in the research of waste paper deinking. As an emerging waste paper deinking technology, enzymatic deinking can not only increase the whiteness of deinked pulp, improve the pulp yield, and reduce the ash content compared with traditional chemical deinking, but also improve the physical properties of waste paper pulp by utilizing the modification effect of enzymes on fibers. In addition, the BOD and COD in the wastewater generated during enzymatic deinking are much lower than those of traditional chemical methods, which reduces the cost of subsequent wastewater treatment and meets people's requirements for environmental protection.

[0005] However, compared with office printing paper, which has a higher whiteness and a lower effective residual ink concentration (ERIC), waste newspapers have a higher ink content. It is difficult to achieve the ideal deinking effect by using the method for ordinary printing paper to deink waste newspapers. In addition, a large amount of enzyme preparations need to be consumed, or waste newspapers need to be deinked together with high-whiteness, low-ERIC papers such as office printing paper, or enzyme activators and more surfactants need to be added. The high processing cost undoubtedly restricts the application of enzymatic deinking in waste newspaper deinking. Summary of the invention

[0006] In view of the above problems, the present invention provides a composite enzyme preparation for waste paper deinking, an enzymatic deinking method and application. The composite enzyme preparation and the enzymatic deinking method can effectively deink waste paper, especially waste newspapers, improve the whiteness of the obtained pulp, and significantly reduce ERIC. The treatment process does not require the use of a large amount of chemicals, thereby solving the problem of environmental pollution caused by the use of a large amount of chemicals in the chemical deinking method. The amount of enzyme and surfactant used is small, and no enzyme activator needs to be added, which is convenient for wide application in the deinking of waste newspapers.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme: A first aspect of the present invention provides a composite enzyme preparation for waste paper deinking, the composite enzyme preparation comprising lipase, cellulase, amylase and xylanase.

[0008] The composite enzyme preparation can destroy the pulp fiber structure, thereby causing the ink spots on the fiber surface to fall off as the fibers depolymerize, and the various enzymes have a synergistic effect, so that an excellent deinking effect can be produced at a lower dosage. Experiments have shown that the effect of deinking waste newspapers using the composite enzyme preparation of the present invention is significantly better than the chemical deinking effect and the deinking effect of using a single enzyme. In addition, deinking using the composite enzyme preparation does not require the use of a large amount of chemicals, is very environmentally friendly, and reduces the pressure and cost of environmental protection.

[0009] Preferably, the enzyme activity ratio of the lipase, cellulase, amylase and xylanase is (0.5-1.5): (1-3): (0.5-1.5): (1-3).

[0010] More preferably, the enzyme activity ratio of the lipase, cellulase, amylase and xylanase is 0.5:2:1.5:1; or, the enzyme activity ratio of the lipase, cellulase, amylase and xylanase is 1.5:2:1.5:2.

[0011] The second aspect of the present invention provides an enzymatic deinking method for waste paper deinking, which specifically comprises the following steps: S1. Soaking waste paper in a Tween 80 aqueous solution, then diluting, crushing and pulping, filtering water, and obtaining waste paper pulp; S2, using the composite enzyme preparation to perform enzyme treatment on the waste paper pulp; S3, flotation and filtration to obtain deinked pulp.

[0012] Preferably, the mass concentration of the waste paper in the Tween 80 aqueous solution is 15% to 20% w / w. Further preferably, the mass concentration of the waste paper in the Tween 80 aqueous solution is 15% w / w.

[0013] Preferably, the mass of Tween in the Tween 80 aqueous solution is 0.05% of the mass of the waste paper.

[0014] Preferably, the waste paper is immersed in the Tween 80 aqueous solution in a 40±2° C. water bath for 10 to 20 min. A further preferred immersion time is 10 min.

[0015] Preferably, the dilution is: adding warm water at 40±2°C until the concentration of the waste paper is reduced to 3% to 4.5% w / w. Further preferably, adding warm water at 40±2°C until the concentration of the waste paper is reduced to 4.5% w / w.

[0016] Optionally, a high-concentration hydraulic pulper may be used for the pulverization and pulping, and the pulping is performed at a constant temperature of 40±2° C. until there is no flaky solid. Optionally, the pulping time may be selected to be 20 min, which pulping time can obtain a uniform liquid pulp without flaky solid.

[0017] Preferably, the dosage of the composite enzyme preparation in S2 is: based on the dry pulp (ODP) in the waste paper pulp, the dosage of the lipase is 0.5~1.5 U per gram of dry pulp, the dosage of the cellulase is 1~3 U, the dosage of the amylase is 0.5~1.5 U, and the dosage of the xylanase is 1~3 U.

[0018] More preferably, the amount of the lipase per gram of dry pulp is 0.5 U, the amount of the cellulase is 2 U, the amount of the amylase is 1.5 U, and the amount of the xylanase is 1 U; or, the amount of the lipase per gram of dry pulp is 1.5 U, the amount of the cellulase is 2 U, the amount of the amylase is 1.5 U, and the amount of the xylanase is 2 U.

[0019] Preferably, the operation of the enzyme treatment in S2 is: after adding the composite enzyme preparation, the pulp concentration (concentration based on dry pulp) is adjusted to 8%~12% with 0.1 mol / L sodium phosphate buffer solution, and treated at 50±2°C for 15~60 min. Further preferably, after adding the composite enzyme preparation, the pulp concentration (concentration based on dry pulp) is adjusted to 10% with 0.1 mol / L sodium phosphate buffer solution, and treated at 50±2°C for 60 min. Optionally, during the enzyme treatment process, the pulp is mixed once every 15 minutes by kneading, stirring, etc., so that the enzyme and pulp are mixed more fully.

[0020] Preferably, the flotation conditions in S3 are to add water to adjust the slurry concentration to 1%, and flotate at 40±2°C for 5 to 15 minutes, more preferably 10 minutes.

[0021] The third aspect of the present invention provides the use of the above-mentioned composite enzyme preparation in deinking of waste newspapers.

[0022] A fourth aspect of the present invention provides application of the enzymatic deinking method in deinking waste newspapers.

[0023] The beneficial effects of the present invention are as follows: deinking waste paper using the composite enzyme preparation and deinking method of the present invention can improve the whiteness of the obtained pulp and reduce ERIC, and the deinking process does not require the use of any other chemicals except a small amount of Tween, thereby solving the problem of water pollution in deinking using conventional chemical methods. In addition, since the various enzymes in the composite enzyme preparation of the present invention have a synergistic effect, the composite enzyme preparation and deinking method of the present invention can produce excellent deinking effects when the dosage of enzymes and surfactants is low, enzyme activators are not used, and office paper does not need to be added. The composite enzyme preparation and deinking method are particularly suitable for deinking waste newspapers, and can not only increase the whiteness of the obtained pulp to more than 65% ISO, but also reduce ERIC to less than 104 ppm, and can be widely used in deinking waste newspapers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The whiteness of the deinked pulp obtained in Example 12 to Example 22 and the comparative example in Test Example 1 of the present invention; Figure 2 is the effective residual ink concentration (ERIC) of the deinked pulp obtained in Examples 12 to 22 and the comparative example in Test Example 1 of the present invention; Figure 3 The Fourier transform infrared spectra of the deinked pulp obtained in Example 12, Example 13 and the comparative example in Test Example 2 of the present invention are shown; Figure 4 These are scanning electron microscope photographs of the deinked pulp obtained in Example 12 (Figure a), Example 13 (Figure b), and Comparative Example (Figure c) in Test Example 2 of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work fall within the scope of protection of the present invention.

[0026] Waste paper deinking is one of the key links in the recycling of waste paper. The current waste paper deinking method is mainly chemical deinking, which has problems such as environmental pollution due to the use of a large amount of chemicals. Enzymatic deinking can avoid the use of a large amount of chemicals, but when it is applied to the deinking of waste newspapers with low whiteness and high ERIC, it needs to consume a large amount of enzyme preparations, or it is necessary to deink the waste newspapers together with paper with high whiteness and low ERIC such as office printing paper, or it is necessary to add enzyme activators and more surfactants, which has many restrictions and high processing costs.

[0027] To address this problem, an embodiment of the present invention provides a composite enzyme preparation for waste paper deinking, which includes lipase, cellulase, amylase and xylanase. The composite enzyme preparation can produce excellent deinking effect at a relatively low dosage, is suitable for waste newspaper deinking, has low surfactant requirements, does not require enzyme activators, and does not require the addition of other papers, and has good application prospects in waste paper deinking, especially in waste newspaper deinking.

[0028] The embodiment of the present invention also provides an enzymatic deinking method for deinking waste paper.

[0029] The embodiment of the present invention also provides the use of the composite enzyme preparation and the enzymatic deinking method in deinking waste newspapers.

[0030] The scheme of the present invention is described below through specific embodiments.

[0031] Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art; the materials, reagents, etc. used in the following examples can be obtained from commercial channels.

[0032] Example 1 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 1.5:2:1.5:2.

[0033] Example 2 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 0.5:2:1.5:1.

[0034] Example 3 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 0.5:1:0.5:1.

[0035] Example 4 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 0.5:2:1:3.

[0036] Example 5 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 0.5:3:1.5:2.

[0037] Example 6 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 1:3:0.5:3.

[0038] Example 7 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 1:1:1:2.

[0039] Example 8 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 1:2:1.5:1.

[0040] Example 9 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 1.5:2:0.5:2.

[0041] Example 10 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 1.5:3:1:1.

[0042] Embodiment 11 This embodiment provides a composite enzyme preparation for waste paper deinking, which is composed of lipase, cellulase, amylase and xylanase, and the enzyme activity ratio of lipase, cellulase, amylase and xylanase is 1.5:1:1.5:3.

[0043] Embodiment 12 to Embodiment 22 Embodiments 12 to 22 provide an enzymatic deinking method for deinking waste newspapers, the specific steps of which are: (1) Pulping The waste newspaper sample was immersed in an aqueous solution containing 0.0075% (w / w) Tween-80 at a concentration of 15% (w / w), placed in a water bath at 40±2℃ for 10 min, and then 40℃ warm water was added to reduce the concentration of the waste newspaper to 4.5% w / w, and then added to a high-consistency hydraulic pulper for pulping. The pulping was carried out at a constant temperature of 40±2℃ for 20 min, and the water was filtered to obtain waste paper pulp.

[0044] (2) Enzyme treatment The above waste paper pulp was placed in a sealed bag, and the composite enzyme preparations in Examples 1 to 11 were added respectively. The addition amounts of lipase, cellulase, amylase and xylanase in each example are shown in Table 1. Then the pulp concentration was adjusted to 10% with 0.1 mol / L sodium phosphate buffer solution, and reacted in a constant temperature water bath at 50±2°C for 60 min, during which the pulp was manually kneaded every 15 min.

[0045] (3) Flotation The waste paper pulp after enzyme treatment was floated in a laboratory flotation tank. The flotation conditions were as follows: the pulp concentration was adjusted to 1% by heating water, the temperature was 40±2℃, and the flotation time was 10 min. After the pulp after flotation was filtered, the deinked pulp was obtained. The deinked pulp was sealed and stored at 4℃.

[0046] Table 1 The amount of enzymes added in Examples 12 to 22

[0047] Comparative Example 1 This comparative example provides a chemical deinking method for deinking waste newspapers, and the specific steps are as follows: (1) Pulping: Same as Example 12.

[0048] (2) Chemical treatment Place the above waste paper pulp in a sealed bag, add Tween-80 (0.05%), sodium hydroxide (2%), H2O2 (1%), DTPA (0.5%) and sodium silicate (2.5%) solutions, then adjust the pulp concentration to 5% with water, and react in a constant temperature water bath at 50°C for 15 minutes (since the solution contains alkali, too long a reaction time may cause the pulp to turn black).

[0049] (3) Flotation: Same as Example 12.

[0050] Comparative Example 2 This comparative example provides an enzymatic deinking method for deinking waste newspapers, and the specific steps are as follows: (1) Pulping: Same as Example 12.

[0051] (2) Enzyme treatment The above waste paper pulp was placed in a sealed bag, 2 U / g ODP lipase was added, and then the pulp concentration was adjusted to 10% with 0.1 mol / L sodium phosphate buffer solution. The pulp was reacted in a constant temperature water bath at 50±2℃ for 60 min, during which it was manually kneaded every 15 min.

[0052] (3) Flotation: Same as Example 12.

[0053] Comparative Example 3 This comparative example provides an enzymatic deinking method for deinking waste newspapers, and the specific steps are as follows: (1) Pulping: Same as Example 12.

[0054] (2) Enzyme treatment The above waste paper pulp was placed in a sealed bag, 4 U / g ODP cellulase was added, and then the pulp concentration was adjusted to 10% with 0.1 mol / L sodium phosphate buffer solution. The pulp was reacted in a constant temperature water bath at 50±2℃ for 60 min, during which it was manually kneaded every 15 min.

[0055] (3) Flotation: Same as Example 12.

[0056] Comparative Example 4 This comparative example provides an enzymatic deinking method for deinking waste newspapers, and the specific steps are as follows: (1) Pulping: Same as Example 12.

[0057] (2) Enzyme treatment The above waste paper pulp was placed in a sealed bag, 2 U / g ODP amylase was added, and then the pulp concentration was adjusted to 10% with 0.1 mol / L sodium phosphate buffer solution. The pulp was reacted in a constant temperature water bath at 50±2℃ for 60 min, during which it was manually kneaded every 15 min.

[0058] (3) Flotation: Same as Example 12.

[0059] Comparative Example 5 This comparative example provides an enzymatic deinking method for deinking waste newspapers, and the specific steps are as follows: (1) Pulping: Same as Example 12.

[0060] (2) Enzyme treatment The above waste paper pulp was placed in a sealed bag, 4 U / g ODP xylanase was added, and then the pulp concentration was adjusted to 10% with 0.1 mol / L sodium phosphate buffer solution. The pulp was reacted in a constant temperature water bath at 50±2℃ for 60 min, during which it was manually kneaded every 15 min.

[0061] (3) Flotation: Same as Example 12.

[0062] Test Example 1 The whiteness and ERIC of the deinked pulp obtained in Examples 12 to 22 and Comparative Examples 1 to 5 were measured: the deinked pulp was sheeted with a standard sheeter, with a basis weight of 60 g / m 2 The whiteness and ERIC of the hand-coated sheets were measured using a whiteness meter in accordance with national standards GB / T22880-2008 and GB / T 20216-2016. The results are shown in Table 2. Figure 1, Figure 2 shown.

[0063] Table 2 Whiteness and ERIC of deinked pulp obtained from Examples 12 to 22

[0064] From the above results, it can be seen that the whiteness of the pulp after chemical deinking is significantly lower than that of each embodiment, and compared with the embodiments with lower whiteness, the ERIC of the pulp after chemical deinking is higher, indicating that the deinking effect of waste newspaper using the composite enzyme preparation of the present invention is significantly better than that of chemical deinking. Moreover, in the deinking process, deinking using the composite enzyme preparation does not require the use of chemical reagents, which is very environmentally friendly.

[0065] Compared with the comparative example using a single enzyme, the deinked pulp obtained in each example has higher brightness and lower ERIC. In particular, in Example 14, when the total amount of enzyme is only 3 U / g ODP, the brightness is significantly higher than that of comparative examples 2 to 5 and the ERIC is significantly lower than that of comparative examples 2 to 5, indicating that the enzymes have a synergistic effect in improving the brightness of pulp and reducing ERIC.

[0066] Test Example 2 The deinked pulp obtained in Example 12, Example 13 and the comparative example was subjected to infrared spectroscopy analysis and scanning electron microscope analysis.

[0067] (1) Infrared spectroscopy analysis of deinked pulp The deinked pulp was evenly dispersed in water and freeze-dried. The dried sample was mixed and ground with potassium bromide at a mass ratio of 1:100, and then pressed into a transparent sheet and placed in a spectrometer for scanning analysis. The scanning wave number was set to 4000-400 cm -1 , resolution 4 cm -1 The results are shown in Table 3 and Figure 3 shown.

[0068] Table 3 Structural attribution of infrared spectral absorption peaks and absorbance of deinked pulps treated by different methods

[0069] The lignin and hemicellulose of the fiber contain a large number of chromophores and auxochromes. 3424~3427cm -1 The strong absorption band is the stretching vibration area of ​​-OH. Compared with the chemical deinking method, the absorbance of the deinked pulp treated in Example 12 and Example 13 is weakened to varying degrees, indicating that some color-enhancing groups such as alcohol hydroxyl and phenolic hydroxyl have changed during the deinking process. 2905~2907cm -1The positions represent different forms of phenolic hydroxyl stretching vibrations. The absorbance of the deinked pulp treated in Examples 12 and 13 decreased significantly, with that in Example 12 being lower. 1626~1629cm -1 Conjugated carbonyl, 1508cm -1 The absorption intensity of the benzene rings is also weakened after deinking, indicating that the number of these two main chromophores changes after deinking. Xylanase can remove lignin, and the synergistic effect between enzyme preparations amplifies this effect, so the absorption intensity of the deinked pulp treated in Example 12 and Example 13 is lower. The reduction of these chromophores and auxochromes is also the main reason for the increase in the whiteness of the deinked pulp. The absorption intensity of the benzene ring in Example 12 is lower, and the absorption intensity of the conjugated carbonyl in Example 13 is lower. 1426cm -1 The vibration at 1376~1379cm represents the methoxy absorption peak. -1 The absorption peak at 896 cm is caused by the CH bending vibration of cellulose and hemicellulose. -1 The absorption peaks at are the vibrations of hemicellulose anomeric carbon (C1). The absorption intensities of the deinked pulps treated in Examples 12 and 13 are reduced, which is most likely caused by the degradation and dissolution of lignin. The absorption intensities of the deinked pulps treated in Examples 12 and 13 are similar in the above three locations. Based on the values ​​of the infrared spectrum absorption peaks of the deinked pulps, the fiber pyrolysis degree of the deinked pulp treated in Example 12 is greater than that of the deinked pulp treated in Example 13, but the effects of their deinking treatments are better than those of chemical deinked pulps.

[0070] (2) Scanning electron microscopy analysis of deinked pulp De-inked pulp was dispersed in deionized water at a concentration of 2% w / w, and an appropriate amount was freeze-dried. A small amount of sample was clamped on the conductive glue with tweezers, sprayed with gold for 60 s and cycled 3 times, and then placed in an observation room for scanning test, with the test voltage set to 5 kV. The results are shown in Figure 2. Figure 4 shown.

[0071] The three groups of deinked pulp fibers had rough surfaces with peeling and breaking, and a certain degree of dissociation occurred, exposing the internal structure. The degree of dissociation of the deinked pulp treated in Example 12 and Example 13 was greater than that of the chemical deinked pulp. The fiber structure of the deinked pulp treated in Example 12 was the most severely damaged, which was consistent with the FTIR results. Its internal structure was also partially depolymerized, which may be caused by the enzymatic hydrolysis of xylanase, indicating that the ink spots on the fiber surface will also fall off as the fiber depolymerizes.

[0072] Embodiment 23 This embodiment discloses an enzymatic deinking method for deinking waste newspapers, and the specific steps are as follows: (1) Pulping The waste newspaper sample was immersed in an aqueous solution containing 0.01% (w / w) Tween-80 at a concentration of 20% (w / w), and placed in a water bath at 40±2℃ for 20 min. Then, 42℃ warm water was added to reduce the concentration of the waste newspaper to 3.5% w / w. The waste newspaper was then added to a high-consistency hydraulic pulper for pulping. The pulping was carried out at a constant temperature of 40±2℃ for 20 min, and the water was filtered to obtain waste paper pulp.

[0073] (2) Enzyme treatment The waste paper pulp was placed in a sealed bag, and the composite enzyme preparation of Example 1 was added, with the dosage of lipase being 1.5 U, cellulase being 2 U, amylase being 1.5 U, and xylanase being 2 U per gram of dry pulp. The pulp concentration was then adjusted to 8% with 0.1 mol / L sodium phosphate buffer solution, and reacted in a constant temperature water bath at 50±2°C for 15 minutes.

[0074] (3) Flotation The waste paper pulp after enzyme treatment was floated in a laboratory flotation tank. The flotation conditions were as follows: the pulp concentration was adjusted to 1% by heating water, the temperature was 40±2℃, and the flotation time was 5 min. After the pulp after flotation was filtered, the deinked pulp was obtained. The deinked pulp was sealed and stored at 4℃.

[0075] Embodiment 24 This embodiment discloses an enzymatic deinking method for deinking waste newspapers, and the specific steps are as follows: (1) Pulping The waste newspaper sample was immersed in an aqueous solution containing 0.0075% (w / w) Tween-80 at a concentration of 15% (w / w), placed in a water bath at 40±2℃ for 15 min, and then 38℃ warm water was added to reduce the concentration of the waste newspaper to 3% w / w, and then added to a high-consistency hydraulic pulper for pulping, and pulping was carried out at a constant temperature of 40±2℃ for 20 min, and the water was filtered to obtain waste paper pulp.

[0076] (2) Enzyme treatment The waste paper pulp was placed in a sealed bag, and the composite enzyme preparation of Example 2 was added respectively, with the dosage of lipase being 0.5 U, cellulase being 2 U, amylase being 1.5 U, and xylanase being 1 U per gram of dry pulp. The pulp concentration was then adjusted to 10% with 0.1 mol / L sodium phosphate buffer solution, and reacted in a constant temperature water bath at 50±2°C for 45 min, during which the pulp was manually kneaded every 5 min.

[0077] (3) Flotation The waste paper pulp after enzyme treatment was floated in a laboratory flotation tank. The flotation conditions were as follows: the pulp concentration was adjusted to 1% by heating water, the temperature was 40±2℃, and the flotation time was 15 min. After the pulp after flotation was filtered, the deinked pulp was obtained. The deinked pulp was sealed and stored at 4℃.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite enzyme preparation for deinking waste paper, characterized in that: Includes lipase, cellulase, amylase and xylanase.

2. The complex enzyme preparation according to claim 1, characterized in that The enzyme activity ratio of the lipase, cellulase, amylase and xylanase is (0.5~1.5) : (1~3) : (0.5~1.5) : (1~3).

3. The complex enzyme preparation according to claim 1 or 2, characterized in that: The enzyme activity ratio of the lipase, cellulase, amylase and xylanase is 0.5﹕2﹕1.5﹕1; or, the enzyme activity ratio of the lipase, cellulase, amylase and xylanase is 1.5﹕2﹕1.5﹕2.

4. An enzymatic deinking method for deinking waste paper, characterized in that: The specific steps include: S1, soaking the waste paper in a Tween 80 aqueous solution, then diluting, crushing and pulping, filtering water, and obtaining waste paper pulp; S2. Performing enzyme treatment on the waste paper pulp using the composite enzyme preparation according to any one of claims 1 to 3; S3, flotation and filtration to obtain deinked pulp.

5. The enzymatic deinking method according to claim 4, characterized in that: The mass concentration of the waste paper in the Tween 80 aqueous solution is 15% to 20% w / w; and / or The mass of Tween in the Tween 80 aqueous solution is 0.05% of the mass of the waste paper; and / or The waste paper is immersed in the Tween 80 aqueous solution in a water bath at 40±2° C. for 10 to 20 min; and / or The dilution is: adding warm water at 40±2°C until the concentration of the waste paper is reduced to 3% to 4.5% w / w; and / or The pulverizing and pulping is carried out using a high-concentration hydraulic pulper, and the pulping is carried out at a constant temperature of 40±2° C. until there is no flaky solid.

6. The enzymatic deinking method according to claim 5, characterized in that: The mass concentration of the waste paper in the Tween 80 aqueous solution is 10% w / w; and / or The waste paper is immersed in the Tween 80 aqueous solution in a water bath at 40±2° C. for 10 min; and / or The dilution is as follows: adding warm water at 40±2° C. until the concentration of the waste paper is reduced to 4.5% w / w.

7. The enzymatic deinking method according to claim 4, characterized in that: The dosage of the composite enzyme preparation in S2 is: based on the dry pulp in the waste paper pulp, the dosage of the lipase is 0.5-1.5 U per gram of dry pulp, the dosage of the cellulase is 1-3 U, the dosage of the amylase is 0.5-1.5 U, and the dosage of the xylanase is 1-3 U; and / or The operation of the enzyme treatment in S2 is: after adding the composite enzyme preparation, adjusting the slurry concentration to 8% to 12% with 0.1 mol / L sodium phosphate buffer solution, and treating at 50±2°C for 15 to 60 min; and / or The flotation conditions described in S3 are to add water to adjust the slurry concentration to 1%, and to flotate at 40±2°C for 5~15 min.

8. The enzymatic deinking method according to claim 7, characterized in that: The amount of the lipase per gram of dry pulp is 0.5 U, the amount of the cellulase is 2 U, the amount of the amylase is 1.5 U, and the amount of the xylanase is 1 U; or, the amount of the lipase per gram of dry pulp is 1.5 U, the amount of the cellulase is 2 U, the amount of the amylase is 1.5 U, and the amount of the xylanase is 2 U; and / or The operation of the enzyme treatment in S2 is: after adding the composite enzyme preparation, adjusting the slurry concentration to 10% with 0.1 mol / L sodium phosphate buffer solution, and treating at 50±2°C for 60 min; and / or Float in S3 at 40±2℃ for 10 min.

9. Use of the composite enzyme preparation according to any one of claims 1 to 3 in deinking of waste newspapers.

10. Use of the enzymatic deinking method according to any one of claims 4 to 8 in deinking waste newspapers.

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