乌拉草纤维素纳米晶须的制备及其在染料吸附中的应用
发布时间：2019-03-27 20:40
【摘要】：乌拉草,又称梡棥草,在中国主要分布于东北地区,因具有天然纤维成本低、来源广、可再生、可生物降解等优点而受到广泛关注。乌拉草原料丰富,化学成分与麻相似,主要含有纤维素、木质素、半纤维素、果胶等,对其进行纤维素提取的研究既可以解决废弃乌拉草对环境的影响,又可以开发其经济价值,实现木质资源的充分利用。本文以乌拉草为原料,通过双相水法成功制得乌拉草纤维,为乌拉草的脱胶技术奠定一定的理论基础;然后将制得的纤维经过机械粉碎、二甲基亚砜(DMSO)预处理和2,2,6,6-四甲基哌啶氧化物(TEMPO)氧化处理得到乌拉草纤维素纳米晶须,并初步探索了纤维素纳米晶须在染料吸附中的应用,为印染废水污染问题提供新的解决途径。本文的主要研究内容包括:(1)乌拉草的基本结构性能表征。对乌拉草进行了化学成分分析、红外光谱测试、X射线衍射测试、扫描电子显微镜测试等,结果表明乌拉草主要含有纤维素、木质素、半纤维素、果胶等成分,且纤维素含量较低,约为19.98%,木质素、半纤维素等成分含量较高;其结晶度较低,为24.12%;在扫描电子显微镜下可以观察到乌拉草表面纵向凹凸不平,横向呈波浪状,且波峰部分由大小不一的孔洞结构组成,波谷部分由实心物质组成。(2)乌拉草纤维提取工艺优化及纤维性能表征。以双相水溶液(聚乙二醇PEG-2000/无机盐溶液)为脱胶方法,制得乌拉草纤维。在脱胶过程中,木质素溶解在含有机物的一相,而纤维素则以固态形式留在无机盐溶液中,实现纤维素与木质素的分离。本文通过单因子控制变量法和正交试验法分析脱胶过程中各种试剂用量、反应时间、反应温度对纤维失重率的影响,确定最佳制备工艺。此外,对最佳提取工艺制得的乌拉草纤维进行化学成分分析、红外光谱测试、x射线衍射测试、扫描电子显微镜测试等,通过分析测试结果可知,与乌拉草原料相比,乌拉草纤维含有较多纤维素,半纤维素、木质素、水溶物等含量明显降低;结晶度显著提高,约为乌拉草原料的近一倍之多,达42%;处理后乌拉草纤维表面较为平滑,大量的杂质被去除。(3)传统碱煮法与双相水溶液法制得纤维的性能对比。为了对比传统碱煮工艺与双相水溶液煮练工艺得到的纤维性能差异,本文又对乌拉草进行传统碱煮处理,并对纤维进行了拉伸强力测试、回潮率测试、长度测试、线密度测试,分析结果表明:双相水溶液法制备的纤维在长度、细度以及拉伸性能等方面均优于传统碱煮法获得的纤维,双相水溶液在纤维脱胶方面具有潜在的应用前景。(4)乌拉草纤维素纳米晶的制备及结构表征。本文以双相水法制得的乌拉草纤维为原料,经过tempo选择性氧化处理,得到乌拉草纤维素纳米晶须,并对它进行透射电子显微镜、扫描电子显微镜、红外光谱测试、x射线衍射分析、热重分析等,得到:乌拉草纤维素纳米晶须呈短棒状,直径为20~60nm,长度为100~300nm;经过冷冻干燥处理的固态纤维素纳米晶须呈薄片状,表面为均匀分布的多孔结构,高孔隙率结构使其在声学、生物医学具有广阔的应用前景;tempo氧化处理后,与乌拉草纤维相比,纤维素纳米晶须的纤维素的含量有所提高;晶型未发生改变,仍然为纤维素Ⅰ型,结晶度为51.01%;当温度达到220℃时,纤维素纳米晶须开始降解,温度达到320℃时,纤维热裂解趋于稳定。(5)初步探索乌拉草纤维素纳米晶须在亚甲基蓝染料吸附中的应用。本文以纤维素纳米晶须沉淀/H_2O_2为吸附体系,研究分析了晶须用量、H_2O_2浓度、吸附时间、吸附温度、染料浓度对吸附反应的影响。综合实验结果表明:当温度为30℃,时间为180min,H_2O_2浓度为2.4mol/l,晶须浓度为0.06g/ml时,染料的去除率为98.76%,此时纤维素纳米晶须对染料的吸附效果最佳。因此,纤维素纳米晶须是亚甲基蓝染料的理想吸附材料之一。
[Abstract]:Ulana, also known as the herbivorous plant, is mainly distributed in the northeast of China, and is widely concerned by the advantages of low cost of natural fiber, wide source, renewable and biodegradable. The raw material is rich, the chemical composition is similar to that of the hemp, mainly contains cellulose, lignin, hemicellulose, pectin and the like, and the research on the cellulose extraction can not only solve the influence of the abandoned ulla grass on the environment, but also can develop the economic value and realize the full utilization of the wood resources. The method comprises the following steps of: taking ulla grass as a raw material, successfully preparing the ulla grass fiber by a two-phase water method, laying a theoretical foundation for the degumming technology of the ulla grass, and then mechanically crushing the prepared fiber, In this paper, the treatment of dimethyl-cellulose nanowhisker by oxidation treatment of 2,2,6,6-tetramethyl-tetramethyl-oxide (TEMPO) was carried out, and the application of the cellulose nanowhisker in the dye adsorption was studied. The new solution for the pollution of printing and dyeing wastewater was also provided. The main contents of this paper are as follows: (1) The basic structural performance of the grass is characterized. The chemical composition analysis, the infrared spectrum test, the X-ray diffraction test and the scanning electron microscope test were carried out on the ulla grass. The results showed that the ulla grass mainly contains the components of cellulose, lignin, hemicellulose, pectin and the like, and the content of the cellulose is lower, about 19.98%, and the lignin, The content of hemicellulose and other components is high; the degree of crystallinity is lower, and is 24.12%; in the scanning electron microscope, the longitudinal and uneven surface of the uralgrass surface can be observed, the lateral direction is in a wave shape, and the wave crest part is composed of a hole structure with different sizes, and the trough part is composed of solid substances. (2) Optimization of the extraction process and characterization of the fiber. A two-phase aqueous solution (polyethylene glycol PEG-2000/ inorganic salt solution) is used as the degumming method to prepare the ulla grass fiber. In the degumming process, the lignin is dissolved in one phase containing organic matters, and the cellulose is left in the inorganic salt solution in a solid state to realize the separation of the cellulose and the lignin. In this paper, the influence of various reagent dosage, reaction time and reaction temperature on the weight loss rate of the fiber is analyzed by single factor control variable method and orthogonal test method, and the optimum preparation process is determined. in addition, chemical composition analysis, infrared spectrum test, x-ray diffraction test, scanning electron microscope test, and the like are carried out on the ulla grass fiber prepared by the optimal extraction process, The content of hemicellulose, lignin, water soluble and the like is obviously reduced, the crystallinity is obviously improved, and the amount of the raw materials is about twice as much as that of the raw materials of the uralgrass, which is up to 42%, and the surface of the uralgrass fiber after treatment is relatively smooth and a large amount of impurities are removed. And (3) the traditional alkali-boiling method and the double-phase aqueous solution are used for preparing the fiber performance comparison. In order to compare the fiber performance difference between the traditional alkali-boiling process and the two-phase aqueous solution scouring process, the traditional alkali-boiling treatment was carried out on the ulla grass, and the fiber was subjected to the tensile strength test, the moisture regain test, the length test and the line density test. The results showed that: The fibers prepared by the two-phase aqueous solution method are superior to the fibers obtained by the traditional alkali cooking method in terms of length, fineness and tensile property, and the like, and the two-phase aqueous solution has potential application prospect in the aspect of fiber degumming. (4) the preparation and the structure characterization of the ulla grass cellulose nanocrystals. In this paper, the ulla grass fiber prepared by two-phase water is used as a raw material, and then is subjected to a temperature selective oxidation treatment to obtain the ulla grass cellulose nanowhisker, and a transmission electron microscope, a scanning electron microscope, an infrared spectrum test, an x-ray diffraction analysis, a thermogravimetric analysis, and the like are carried out, and the preparation method comprises the following steps of: the ulla grass cellulose nano-crystal whisker is in a short rod shape, the diameter is 20-60nm, the length is 100-300nm, the solid-state cellulose nano-crystal whisker subjected to freeze-drying treatment is in a sheet shape, the surface is a porous structure with a uniform distribution, and the high-porosity structure makes the nano-crystal whisker have wide application prospect in acoustics and biomedicine; when the temperature reaches 220 DEG C, the cellulose nanowhisker starts to degrade and the temperature reaches 320 DEG C, The thermal cracking of the fiber is stable. (5) The application of the nano-crystal whisker in the adsorption of methylene blue dye was studied. The influence of the amount of the whiskers, the concentration of H _ 2O _ 2, the adsorption time, the adsorption temperature and the concentration of the dye on the adsorption reaction was studied by using the cellulose nanowhisker precipitation/ H _ 2O _ 2 as the adsorption system. The results show that when the temperature is 30 鈩，
本文编号：2448545
[Abstract]:Ulana, also known as the herbivorous plant, is mainly distributed in the northeast of China, and is widely concerned by the advantages of low cost of natural fiber, wide source, renewable and biodegradable. The raw material is rich, the chemical composition is similar to that of the hemp, mainly contains cellulose, lignin, hemicellulose, pectin and the like, and the research on the cellulose extraction can not only solve the influence of the abandoned ulla grass on the environment, but also can develop the economic value and realize the full utilization of the wood resources. The method comprises the following steps of: taking ulla grass as a raw material, successfully preparing the ulla grass fiber by a two-phase water method, laying a theoretical foundation for the degumming technology of the ulla grass, and then mechanically crushing the prepared fiber, In this paper, the treatment of dimethyl-cellulose nanowhisker by oxidation treatment of 2,2,6,6-tetramethyl-tetramethyl-oxide (TEMPO) was carried out, and the application of the cellulose nanowhisker in the dye adsorption was studied. The new solution for the pollution of printing and dyeing wastewater was also provided. The main contents of this paper are as follows: (1) The basic structural performance of the grass is characterized. The chemical composition analysis, the infrared spectrum test, the X-ray diffraction test and the scanning electron microscope test were carried out on the ulla grass. The results showed that the ulla grass mainly contains the components of cellulose, lignin, hemicellulose, pectin and the like, and the content of the cellulose is lower, about 19.98%, and the lignin, The content of hemicellulose and other components is high; the degree of crystallinity is lower, and is 24.12%; in the scanning electron microscope, the longitudinal and uneven surface of the uralgrass surface can be observed, the lateral direction is in a wave shape, and the wave crest part is composed of a hole structure with different sizes, and the trough part is composed of solid substances. (2) Optimization of the extraction process and characterization of the fiber. A two-phase aqueous solution (polyethylene glycol PEG-2000/ inorganic salt solution) is used as the degumming method to prepare the ulla grass fiber. In the degumming process, the lignin is dissolved in one phase containing organic matters, and the cellulose is left in the inorganic salt solution in a solid state to realize the separation of the cellulose and the lignin. In this paper, the influence of various reagent dosage, reaction time and reaction temperature on the weight loss rate of the fiber is analyzed by single factor control variable method and orthogonal test method, and the optimum preparation process is determined. in addition, chemical composition analysis, infrared spectrum test, x-ray diffraction test, scanning electron microscope test, and the like are carried out on the ulla grass fiber prepared by the optimal extraction process, The content of hemicellulose, lignin, water soluble and the like is obviously reduced, the crystallinity is obviously improved, and the amount of the raw materials is about twice as much as that of the raw materials of the uralgrass, which is up to 42%, and the surface of the uralgrass fiber after treatment is relatively smooth and a large amount of impurities are removed. And (3) the traditional alkali-boiling method and the double-phase aqueous solution are used for preparing the fiber performance comparison. In order to compare the fiber performance difference between the traditional alkali-boiling process and the two-phase aqueous solution scouring process, the traditional alkali-boiling treatment was carried out on the ulla grass, and the fiber was subjected to the tensile strength test, the moisture regain test, the length test and the line density test. The results showed that: The fibers prepared by the two-phase aqueous solution method are superior to the fibers obtained by the traditional alkali cooking method in terms of length, fineness and tensile property, and the like, and the two-phase aqueous solution has potential application prospect in the aspect of fiber degumming. (4) the preparation and the structure characterization of the ulla grass cellulose nanocrystals. In this paper, the ulla grass fiber prepared by two-phase water is used as a raw material, and then is subjected to a temperature selective oxidation treatment to obtain the ulla grass cellulose nanowhisker, and a transmission electron microscope, a scanning electron microscope, an infrared spectrum test, an x-ray diffraction analysis, a thermogravimetric analysis, and the like are carried out, and the preparation method comprises the following steps of: the ulla grass cellulose nano-crystal whisker is in a short rod shape, the diameter is 20-60nm, the length is 100-300nm, the solid-state cellulose nano-crystal whisker subjected to freeze-drying treatment is in a sheet shape, the surface is a porous structure with a uniform distribution, and the high-porosity structure makes the nano-crystal whisker have wide application prospect in acoustics and biomedicine; when the temperature reaches 220 DEG C, the cellulose nanowhisker starts to degrade and the temperature reaches 320 DEG C, The thermal cracking of the fiber is stable. (5) The application of the nano-crystal whisker in the adsorption of methylene blue dye was studied. The influence of the amount of the whiskers, the concentration of H _ 2O _ 2, the adsorption time, the adsorption temperature and the concentration of the dye on the adsorption reaction was studied by using the cellulose nanowhisker precipitation/ H _ 2O _ 2 as the adsorption system. The results show that when the temperature is 30 鈩，
本文编号：2448545
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