PRODUCTION OF SEMI-FINISHED CELLULOSE FROM LOCAL RAW MATERIALS: THE EXAMPLE OF Typha angustifolia L. AND Phragmites communis Trin. PLANTS

ABSTRACT

The article presents the results of an experiment on obtaining semi-finished cellulose from local raw materials - Typha angustifolia L. (narrow-leaved reed) and Phragmites communis Trin. (common reed). Currently, in the paper industry of Uzbekistan, mainly wood-based raw materials are imported, but the prospects for using annual plants widely distributed in the country are high. In the research process, dried and crushed plant samples were first subjected to thermochemical treatment in a 7% nitric acid solution, and then in a 5% sodium hydroxide solution. The resulting semi-finished cellulose was bleached using H₂O₂ and NaOH solutions. According to the results, the cellulose yield from Phragmites communis Trin. was 30%, and from Typha angustifolia L. - 25%. The quality, whiteness and recyclability of the obtained cellulose indicated its potential for use as an effective raw material in the production of paper and other fibrous products. At the same time, the acidic method has more economical and environmental advantages in terms of energy consumption, and in the future it will become an important import-substituting technology in our country.

АННОТАЦИЯ

В статье представлены результаты эксперимента по получению целлюлозного полуфабриката из местного сырья - Typha angustifolia L. (тростника узколистного) и Phragmites communis Trin. (тростника обыкновенного). В настоящее время в бумажной промышленности Узбекистана в основном импортируется древесное сырье, однако перспективы использования широко распространенных в стране однолетних растений высоки. В процессе исследований высушенные и измельченные образцы растений сначала подвергались термохимической обработке в 7% растворе азотной кислоты, а затем в 5% растворе гидроксида натрия. Полученный целлюлозный полуфабрикат отбеливался с использованием растворов H₂O₂ и NaOH. Согласно результатам выход целлюлозы из Phragmites communis Trin. составил 30%, а из Typha angustifolia L. - 25%. Качество, белизна и возможность вторичной переработки полученной целлюлозы свидетельствовали о ее потенциальной возможности использования в качестве эффективного сырья в производстве бумаги и других волокнистых изделий. При этом кислотный метод имеет больше экономических и экологических преимуществ с точки зрения энергопотребления, и в перспективе станет важной импортозамещающей технологией в нашей стране.

Keywords: Typha angustifolia L., Phragmites communis Trin., semi-finished cellulose, annual plants, nitric acid cooking, sodium hydroxide, H₂O₂, paper production, energy-saving technology, local raw materials

Ключевые слова: Typha angustifolia L., Phragmites communis Trin., целлюлозный полуфабрикат, однолетние растения, азотнокислая варка, гидроксид натрия, H₂O₂, производство бумаги, энергосберегающие технологии, местное сырье

Introduction

The production of cellulose and paper products from annual plants is an important technological and environmental direction in modern pulp and paper industries. In recent decades, many countries have introduced innovative cellulose production technologies based on non-wood raw materials, which allow for the efficient use of renewable resources and reduce dependence on imported wood-based materials. Countries such as China and India have achieved significant results by applying acidic, alkaline, and sulfate pulping methods to process annual plants. As a result, these two countries now account for about 77% of the world’s cellulose production from annual plants, with China alone meeting 50% of its paper demand through non-wood raw materials. This demonstrates the wide potential of such technologies in achieving sustainable and energy-efficient production.

In Uzbekistan, a large quantity of agricultural residues and annual plants — including cotton stalks, rice straw, wheat straw, Typha angustifolia L., and Phragmites communis Trin. — are generated every year. However, the country’s paper industry still relies mainly on imported wood-based cellulose, and local technological processes for cellulose production from annual plants have not yet been fully developed. Globally, the share of fibrous semi-finished products obtained from annual plants is distributed as follows: straw – 44%, bagasse – 18%, reed – 25%, bamboo – 13%, and other plants – 11%. These data confirm that annual plants can serve as valuable renewable raw materials for the cellulose and paper industries when processed using appropriate technologies. For instance, in China, reeds are treated with nitric acid at 160 °C for 5–6 hours, producing up to 50–53% of unbleached cellulose, which is subsequently bleached in three stages and used in writing and printing paper production.

Therefore, the development of technological methods for obtaining semi-finished cellulose from local raw materials is of great scientific and practical importance for Uzbekistan. The main purpose of this research is to study the technology of producing semi-finished cellulose from Typha angustifolia L. and Phragmites communis Trin. using the acid-alkaline pulping method, to determine the yield, whiteness, and quality parameters, and to evaluate their potential as alternative raw materials in domestic paper production. The results of this study are expected to support the introduction of energy-saving, environmentally friendly, and import-substituting technologies in the pulp and paper industry of Uzbekistan, contributing to sustainable resource utilization and the development of a circular bioeconomy.

Method

The research aimed to develop an efficient method for obtaining semi-finished cellulose from local annual plants — Typha angustifolia L. and Phragmites communis Trin. — using an acid–alkali pulping process. The methodology was designed based on comparative analysis of traditional industrial pulping techniques and laboratory-scale adaptation to local raw materials.

Among various industrial pulping processes, such as the sulfate, alkaline, and sulfite methods, the acid–alkali (HNO₃–NaOH) approach was selected for this study due to its lower energy consumption, reduced environmental impact, and simplicity in laboratory implementation. Nitric acid treatment effectively breaks down lignin and hemicellulose, while subsequent alkaline treatment (NaOH) removes residual non-cellulosic components and enhances fiber purity. This two-step process provides a balance between cellulose yield and fiber quality, making it suitable for non-woody raw materials commonly found in Uzbekistan.

Samples of Typha angustifolia L. and Phragmites communis Trin. were collected during the winter season from natural reedbeds in the Namangan region. The stems were cleaned, dried, and ground using a laboratory mill. Particles sized 5–10 mm were separated using a sieve for uniformity of treatment. The pre-treated raw material was cooked in a 7% aqueous solution of nitric acid (HNO₃) at 70–80 °C for 3 hours. This stage primarily degraded lignin and facilitated the release of cellulose fibers. After acid treatment, the material was thoroughly washed with running water until the pH reached neutral values (pH 6–7), and then dried at 80 °C for 4 hours. The dried material was treated in a 5% sodium hydroxide (NaOH) solution at 70–80 °C for 2 hours to remove remaining hemicelluloses and impurities. The resulting semi-finished cellulose was bleached using hydrogen peroxide (H₂O₂) and sodium hydroxide (NaOH) solutions to improve whiteness and fiber brightness.

Throughout all stages, the mass of the samples was measured using a precision analytical balance with an accuracy of ±0.01 g. Mass measurements were taken after each treatment step to evaluate cellulose yield and mass loss dynamics. The results were used to calculate cellulose recovery efficiency and compare the two plant species.

Table 1.

Cellulose extraction efficiency of raw materials

The cellulose yield (%) was calculated based on the ratio of the dry mass of bleached cellulose to the initial raw material mass. All measurements were repeated three times, and average values were used to minimize experimental error. The uncertainty of the results was within 0.5%, corresponding to the measurement precision of the analytical equipment.

This methodological framework allowed reliable assessment of the technological feasibility of producing semi-finished cellulose from Typha angustifolia L. and Phragmites communis Trin., and provided a scientific basis for further optimization of acid–alkali pulping for local plant materials.

Results and Discussion

We measured the sample mass at each stage of cellulose extraction to assess the material loss and overall yield for both Typha angustifolia L. and Phragmites communis Trin. As shown in Table 1, the cellulose yield from Phragmites communis Trin. reached 30%, while that from Typha angustifolia L. was 25%. These values are slightly lower than some reported in previous studies, which may be attributed to differences in plant composition, growing conditions, and reaction time.

Despite the slightly lower yield, the nitric acid–alkali method demonstrated several advantages. Compared to conventional sulfate and soda pulping, the process required less energy and shorter treatment duration. Furthermore, the cellulose obtained exhibited high whiteness and uniform fiber morphology, indicating a higher potential for producing writing and printing papers.

Microscopic observations revealed that nitric acid treatment effectively degraded lignin bonds, facilitating the separation of cellulose fibers. The subsequent alkaline treatment removed hemicellulose residues and enhanced fiber flexibility. The bleaching step further improved color uniformity and purity, resulting in semi-finished cellulose suitable for refining into high-grade paper pulp.

Figure 1. Changes in cellulose extraction from Typha angustifolia L. a) The stem of the yam plant, b) The crushed stem of the yam plant, c) The state after cooking in HNO3, d) The state after cooking in Ishqo, f) The appearance after bleaching

These findings confirm that both Typha angustifolia L. and Phragmites communis Trin. can serve as promising alternative raw materials for cellulose production in Uzbekistan. The developed nitric acid–alkali technology offers a cost-effective, energy-saving, and environmentally friendly approach, supporting import substitution and sustainable use of local plant resources.

Figure 2. Changes in cellulose production from Phragmites communis Trin. a) The stem of a reed plant, b) A sample of crushed reed, c) Reed cooked in nitric acid, d) After cooking in alkali, f) After bleaching.

Conclusion

The conducted research demonstrates that local plant species Typha angustifolia L. (narrowleaf cattail) and Phragmites communis Trin. (common reed) are viable and efficient sources of semi-finished cellulose. The modified nitric acid–alkali pulping method used in this study enabled the isolation of high-quality cellulose with satisfactory yield and whiteness.

The stepwise analysis showed that during acid and alkali treatment, lignin and hemicellulose were effectively removed, leading to purified cellulose fibers. The cellulose yield obtained was 30% for Phragmites communis and 25% for Typha angustifolia. These results indicate that both plants can serve as promising alternative raw materials for the domestic pulp and paper industry.

The use of local annual plants instead of wood resources has important economic and environmental benefits. It reduces deforestation pressure, promotes the utilization of renewable biomass, and contributes to sustainable resource management in Uzbekistan. Moreover, the nitric acid–alkali method is less energy-intensive and environmentally safer compared to traditional sulfate or soda pulping technologies.

In summary, the study confirms that Typha angustifolia L. and Phragmites communis Trin. can be effectively processed into semi-finished cellulose suitable for further paper production. Future research should focus on optimizing bleaching parameters, improving fiber strength, and scaling up the process for industrial application.

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