Biological enzymes or washing paper industry 'original sin'

"Bio-refining can recycle various components of non-wood fiber raw materials, especially the high-value utilization of hemicellulose and lignin." Dai Hongqi told reporters.

Lignin accounts for about 20%-40% of the composition of non-wood fiber raw materials, and traditional pulping is to remove lignin and obtain pulp fibers used as raw materials for paper making. Lignin is a polymer with a three-dimensional network structure connected by benzene propane units through ether bonds and carbon-carbon bonds. Depending on the type of plant fiber raw materials, the aromatic monomer composed of lignin has the function of gaining and losing electrons, can absorb ultraviolet rays, and is also a potential energy storage material.

In the past, the value of lignin has not been well developed and utilized, and the traditional practice of pulp mills is to recover heat energy by burning it. Dai Hongqi introduced that in recent years, based on the special function of lignin phenol hydroxyl aromatic monomer, researchers have replaced phenol with lignin as a green adhesive, energy storage electrolyte/energy storage electrode material, anti-ultraviolet film material and so on.

Another technology direction that is currently favored is high yield chemical mechanical pulp technology. This technology can not only alleviate the bottleneck of the shortage of papermaking fiber raw materials in China, but also has the advantages of low difficulty and low cost in wastewater treatment.

"This technology abandons the idea of extracting the hemicellulose and lignin left over from cellulose in the past, but uses all the wood fiber components as pulp for paper." Dai Hongqi introduced that the high yield chemical mechanical pulp is mainly based on mechanical methods, supplemented by a small amount of biological enzymes and chemical additives, so that the process of pulping wastewater treatment is greatly simplified and the cost is reduced, which can not only replace a large number of imported commercial wood pulp and waste paper raw materials, but also eliminate the huge air pollution problem caused by crop straw incineration.

Dai Hongqi revealed that the paper industry has implemented many scientific research projects and conducted pilot projects in individual enterprises to use wheat grass biological pulping to make household paper, wrapping paper and so on.

Biological enzymes may promote the green transformation of the paper industry

In fact, under the dual pressure of cost and environment, the paper industry is also eager to transform from a major polluter to a model of energy conservation and emission reduction.

In making the paper industry with high pollution and high energy consumption "correct", biological enzyme preparations are playing an increasingly important role.

Dai Hongqi said that biological enzymes have the characteristics of specificity and efficiency. At present, the technical research of the application of biological enzymes in the paper industry is mainly focused on grinding, deinking, bleaching and removing adhesives in the paper making process.

For example, biological enzymes can be used to modify the cell wall of the slurry fiber, so that the fiber can accelerate the moistening and soft, promote the effect of grinding, reduce the energy consumption of grinding, and improve the strength of paper. Studies have shown that bioenzymes can reduce the energy consumption per ton of mill pulp by 41.4%.

In addition, when the paper industry recycles a large amount of waste paper, it needs to be deinked.

The traditional deinking method is to use chemicals, at the appropriate temperature and mechanical action, to separate the ink particles from the fiber, and then use flotation, washing or a combination of the two methods to remove the stripped ink particles from the pulp. Enzymatic deinking is the use of enzymes to treat waste paper, and assisted by flotation or washing, and a combination of both processes, so as to remove ink.

Bleaching is also an important step in the papermaking process. The use of enzyme preparations can play a "biological aid bleaching" effect, reduce the amount of chlorine-containing bleaching chemicals, thereby reducing the discharge of adsorbable organic halides in bleaching wastewater, and reduce environmental pollution.

However, the application of biological enzymes in the paper industry is not smooth sailing.

Dai Hongqi said that the research and development of biological enzyme technology has made some achievements, but there are still bottlenecks in application. So far, there are no real biological pulping plants in the world. The reason is that there are a series of technical difficulties in the application of biological enzymes to complex and large-scale pulping production.

"In addition, pretreatment of raw materials by biological enzymes takes a long time, and manufacturers need efficiency to ensure continuous production, so they prefer to use more efficient physical or chemical pretreatment methods." Dai Hongqi said that some enzyme preparations themselves also have problems such as high cost, limited types, greater impact by temperature and acid and alkaline environment, and low effect. Therefore, at this stage, the application of biological enzyme technology is still auxiliary and can not play a leading role.