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Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

 Федеральный исследовательский центр «Красноярский научный центр Сибирского отделения Российской академии наук»

Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

Krasnoyarsk scientists have learned how to produce cellulose without harm to the environment

20 April 2020 г.

Красноярские ученые научились получать целлюлозу без вреда для окружающей среды
Scientists of the Federal Research Center KSC SB RAS have developed a new method for producing microfibrillated cellulose, which is necessary for the production of biodegradable materials, medical implants and aerogels. The proposed method is less energy-consuming and more environmentally-friendly, as compared to the traditional technologies, due to a one-stage process of producing high-quality pulp. The results of the study are published in the journal “Chemistry of Plant Raw Material”.

When harvesting and processing wood, a huge amount of waste is generated in the form of sawdust, wood chips and shavings which require recycling. A promising area for the use of wood waste is its chemical processing into cellulose and new functional materials, including microfibrillated cellulose. In recent years, interest in such cellulose has markedly increased. Due to its unique properties – light weight, high porosity, non-toxicity, biocompatibility and biodegradability, cellulose is in demand in the production of aerogels, biocomposites, biodegradable materials, medical implants, as well as in the creation of reinforced composite materials based on polymers.

Traditionally, cellulose is obtained by continuous mechanical grinding of a solution of cellulose fibers using high pressure homogenizers, which leads to a uniform state of cellulose. Then, using grinding machines and autoclaves, the final product is obtained. The growing demand for microfibrillated product is restrained due to the main unresolved problem - high energy costs for its production.

Krasnoyarsk chemists have developed a new economical and more environmentally-friendly method of producing cellulose, which includes four main stages: lignin removal from wood chips in an acetic acid-water medium in the presence of a sulfuric acid catalyst, acid hydrolysis, ultrasonic treatment and freeze drying of cellulose.

“The key point in obtaining microcellulose from wood is the process of its delignification, that is, removal of lignin from wood. Traditional methods use hazardous sulfur and chlorine delignifying reagents, high pressure and high water consumption. We suggest a new method for producing cellulose using such “green” oxidizing agents as hydrogen peroxide and oxygen, ” emphasizes one of the authors of the study, Olga Yatsenkova, Candidate of Chemical Sciences, senior researcher at the Institute of Chemistry and Chemical Technology KSC SB RAS.

The scientists are planning to further integrate the process of wood delignification with the preliminary pretreatment of feedstock in order to isolate hemicelluloses for maximum use of valuable chemical products from wood biomass. They are also planning to use environmentally friendly solid acid catalysts at the stage of cellulose hydrolysis instead of corrosive sulfuric acid since the former can be reused.