Journal of Agro-Environmental Science, Issue 11, 2023.
Author:Yang Yi1, Peng Hua1,2,3*, Deng Kai1, Ji Xionghui1,2,3, Dai Yanjiao1, Song Min1
Unit:1.Hunan Academy of Agricultural Sciences, Hunan Provincial Institute of Agricultural Environment and Ecology;2.Key Laboratory of Agricultural Environment in the Middle Reaches of the Yangtze River Plain, Ministry of Agriculture and Rural Affairs;3.Engineering Technology Research Center for Prevention and Control of Agricultural Non-point Source Pollution in Dongting Lake Basin, Hunan Province.
Summary
The high-value utilization of agricultural waste can help alleviate resource constraints and reduce environmental pollution. Straw cellulose is the most important substance in the cell wall, which is stably nested with lignin and hemicellulose and is difficult to separate. Therefore, the separation and extraction of effective components of straw is the basis and key to realize its high-value utilization. In this paper, the microstructure, formation mechanism and physicochemical properties of fibers in straw are elaborated, various techniques for extracting cellulose are introduced, and the principles and advantages and disadvantages of cellulose separation are condensed. In view of the existing technical barriers and limitations, this paper looks forward to the research fields and development directions of straw fiber separation, extraction and purification, in order to lay a foundation for exploring efficient, green and environmentally friendly technology and realizing the high-value utilization of straw cellulose.
Conclusions and prospectsAs a multi-functional material, plant cellulose can be widely used in high-tech fields such as medicine, environmental protection, chemical industry, electronic technology, etc., to realize waste reuse and create economic value. However, based on the cellulose extraction methods explored in the past few decades, the optimal extraction scheme that can be widely used in industrial production has not yet been found under the consideration of cost, economy, environment and other factors. Therefore, this paper reviews the mechanism, advantages and disadvantages of different types of extraction technologies such as physics, chemistry and biology, in order to provide a theoretical basis for the industrial production of high-precision cellulose. Research has shown that each treatment technology has its own unique advantages, but also significant drawbacks. Currently, multi-force co-processing technology offers greater potential than single pretreatment due to its flexibility and adaptability in a wide range of materials and processing conditions. The comprehensive evaluation shows that the physicochemical pretreatment has high efficiency and short pretreatment time, and has great potential for large-scale application, but it is still necessary to reduce the cost and energy consumption of pretreatment, and eliminate the generation of secondary inhibitors. Biochemical and physicobiological pretreatment can be performed under mild conditions, but it is costly, demanding environmental conditions, and long processing times. Although most of the combined treatments can effectively improve the yield and quality of straw fiber, it is necessary to optimize the single extraction technology and study the synergistic mechanism to further improve the joint effect.
Considering that the current extraction technology is affected by many factors such as equipment conditions, cost, environment, etc., combined with the extraction characteristics of various methods and the current status of industrial level, the following suggestions are put forward:
1) The physical method should further improve the supporting facilities and equipment, increase the crushing intensity, and keep the scale of the crushed material at the micron level in order to significantly improve the extraction efficiency of subsequent treatment.
2) The chemical method should be based on the existing non-acid and non-alkali efficient green extraction technology from the perspectives of economy, environmental protection, energy conservation and emission reduction, and further increase research efforts to realize industrial production to replace acid and alkali reagents.
3) Biological methods should optimize the culture conditions of functional strains, mutagenesis breeding and even genetic engineering to optimize the screening of functional microorganisms to achieve the purpose of high efficiency and high yield.
4) The joint method should break down the technical barriers, optimize the physical, chemical and biological single extraction technology from the perspectives of economy, environmental protection and high yield, and explore the influence mechanism of the coordination mode, so as to lay a foundation for further exploring the joint extraction mode with high efficiency, high purity, low cost and green safety.
Editor: Zhang Dandan.
Proofreading |Review: Pan Shujun, Wang Nong.
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