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接枝羧基纤维素在重金属废水治理中的应用研究 总被引:3,自引:0,他引:3
采用羧甲基纤维素接枝聚丙烯合成重金属捕集剂,研究了对多种重金属废水的静态吸附和动态吸附性能,探讨了介质pH对其吸附性能的影响。 相似文献
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We prepared spherical microcapsules modified by carboxymethyl cellulose(CMC) with urea-formaldehyde(UF) resin as a shell material with a two-step process by in situ polymerization, and characterized the microcosmic features, chemical structure, and thermal performance of the microcapsules by SEM, FTIR, DSC, and TGA. We studied the effects of different experimental parameters of curing p H, the amounts of the emulsifier and emulsion speed. The CMC-UF microcapsules had good heat resistance and stability. The enthalpy of CMC-UF microcapsules reached 50.33 J g-1. Therefore, CMC-UF resin can be used as a potential wall material of phase change materials. 相似文献
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在氧化镁载体上浸渍醋酸钙后烧结制备了CaO/MgO复合固体碱催化剂,所制固体碱催化剂的表面碱度与催化剂制备条件有关:当CaO/MgO比值为0.08、在700℃下煅烧时间24 h时制得的催化剂表面碱度可达到30.2 mmol/g.以该固体碱催化剂催化木质素中醚键断裂反应,测试结果表明木质素降解产物重均相对分子质量(Mw)可从3000降低至800以下,羟值由200 mg/g增加至480 mg/g左右.FT-IR表征结果表明降解产物中醚键含量明显减少,羟基含量增多. 相似文献
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在氧化镁载体上浸渍醋酸钙后烧结制备了CaO/MgO复合固体碱催化剂,所制固体碱催化剂的表面碱度与催化剂制备条件有关:当CaO/MgO比值为0.08、在700℃下煅烧时间24 h时制得的催化剂表面碱度可达到30.2 mmol/g。以该固体碱催化剂催化木质素中醚键断裂反应,测试结果表明木质素降解产物重均相对分子质量(Mw)可从3 000降低至800以下,羟值由200 mg/g增加至480 mg/g左右。FT-IR表征结果表明降解产物中醚键含量明显减少,羟基含量增多。 相似文献
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Summary We describe a way of fragmenting the lignocellulose material in furze (Ulex europæus) stems by chemical means. The process separates the three principal components in the stem: cellulose, hemicelluloses and lignin, by the joint action of a mixture of dilute hydrochloric acid to hydrolyse the hemicelluloses, and phenol, to dissolve the lignin. The effects of the process variables on the yield have been studied. The fractions obtained have been characterized and methods for their use are proposed. 相似文献
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Summary In an X-ray diffraction investigation, the recrystallization behavior of ball-milled Chinese southern pine wood was found to differ from that of cellulose. The crystallinity of lignocellulose milled for a very long time and recrystallized by wetting in water did not decrease with increasing milling time as was the case with milled cellulose. In addition, it appeared that the presence of lignin tended to restrict the amorphous cellulose produced by milling from recrystallizing into Cellulose II, whereas it had no influence on the recrystallization into Cellulose I. These results were discussed in the context of the mechanism of the conversion of Cellulose I to Cellulose II. 相似文献
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As one of the major components of plant cell walls, lignin structural features are closely related with taxonomical and genetic
classification of plants. In this study, the structural features of lignin of Abies beshanzuensis were investigated. Abies firma, which is genetically the closest species to A. beshanzuensis, Cryptomeria japonica, a typical gymnosperm tree species, and Phyllostachys pubescens (bamboo), which includes p-hydroxyphenyl nuclei in arylglycerol-β-aryl intermonomer linkages, were also analyzed to compare lignin features with those
of A. beshanzuensis. The lignin content of A. beshanzuensis (39.2%) was significantly higher than that of A. firma (33.7%). The high value may be due to the adaptation of A. beshanzuensis to environmental stresses in surviving the Riss glacial period. Alkaline nitrobenzene oxidation, ozonation, acidolysis, and
1H nuclear magnetic resonance spectra showed that the structural features of lignin of A. beshanzuensis were similar to those of A. firma, which is genetically the closest species of A. beshanzuensis. The results of this study suggest that A. firma would be a suitable mother tree species for grafting A. beshanzuensis on the basis of their lignin characteristics. 相似文献
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毛白杨木材乙二醇醇解过程中木质素结构的FT-IR、1H NMR分析 总被引:1,自引:0,他引:1
为探讨木材乙二醇醇解过程中木质素结构的变化机理,以毛白杨磨木木质素(MWL)为研究对象,采用红外光谱和核磁共振等手段对醇解前后的木质素结构变化进行了分析.发现毛白杨木质素属于典型的愈创木基-紫丁香基型(GS型)木质素,G/S比值为1.37.醇解过程中木质素单元间β-O-4连接键大量断开,共轭羰基减少,甲基芳基醚键部分断开,产物中发现了大量新的酚羟基结构.醇解产生的低分子组分有芳香醚类、脂肪醚类、酚类、芳香酸类、不饱和酮类等物质.木质素大分子断裂的同时也有缩合反应发生. 相似文献
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棉秆木质素的光谱分析 总被引:4,自引:1,他引:3
采用球磨方法分离并提纯出棉秆全秆磨木木质素(MWL)和棉秆秆芯MWL.采用紫外光谱和红外光谱对上述分离出的木质素进行分析.并用 13 C NMR 作了进一步分析研究.从分析结果看出:棉秆木质素属于愈疮木基-紫丁香-对羟苯基(GSH)型.棉秆秆皮和秆芯木质素结构不同,在秆皮中存在较多的紫丁香基结构单元和少量的对羟苯基结构,而秆芯中以紫丁香基结构单元和愈疮木基结构单元为主. 相似文献
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以黄孢原毛平革菌基因组DNA为模板,克隆Lip-2基因片段,结合序列测定和生物信息学方法对扩增序列进行分析,结果证实所获得的序列与GenBank中已经登陆的Lip-H8基因具有高度的同源性,其N-端也具有真核生物分泌型信号肽序列.Lip-2基因序列的获得为下一步将其构建到酵母表达载体中进行蛋白质表达奠定了基础. 相似文献
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研究了碱法制浆副产物麦草碱木质素的磺化产品磺化碱木质素(SWSL)作为混凝土减水剂使用的性能,掺量(相时于水泥的质量分数,下同)为0.25%时,掺SWSL的混凝土减水率达13.5%,较掺木质素磺酸钙(CLS)的(10.2%)高,混凝土3天和7天龄期抗压强度比仅为113%和105%,较掺CLS的(134%和125%)低.SWSL在水泥浆碱性溶液中具有较好起泡性和泡沫稳定性,有较高的减水率,但泡径较粗且分布不均匀,最大泡径为2 mm,导致硬化砂浆密度减小,孔径小于0.01 mm的气孔比例相对较少,孔径在0.01~0.05 mm范围的较多,抗压强度下降.SWSL的磺化度为1.1 mmol/g,重均相对分子质量(MW)为4 424,较木钙(11 370)低.较低的磺化度使SWSL的分散性能比木钙差. 相似文献
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Trochodendron aralioides Sieb. et Zucc. and Chloranthus glaber (Thunb.) Makino [Sarcandra globra (Thunb.) Nakai] belong to primitive angiosperms, and are characterized by the absence of vessels. Ephedra sinica Stapf, which is classified in the gymnosperms, contains vessel elements and fiber together with tracheids. Podocarpus macrophyllus (Thunb. Ex Murray) D. Don var. macrophyllus is reported to give a weak positive Mäule test, although it is classified as a gymnosperm. Podocarpus macrophyllus gave only vanillin on alkaline nitrobenzene oxidation, while E. sinica, T. aralioides, and C. glaber gave both vanillin and syringaldehyde. The molar ratio of syringyl to guaiacyl nuclei (S/V ratio) of C. glaber was significantly low (S/V = 0.08) in comparison with the value for T. aralioides (S/V = 1.56). The erythro form is the predominant diasteromeric form of β-O-4 intermonomer linkages of T. aralioides and E. sinica [molar ratio of erythro to threo forms (E/T ratio): 1.93 and 1.67, respectively]; however, P. macrophyllus and C. glaber lignins, of which S/V ratios were 0 and 0.08, gave approximately equal amounts of erythro and threo forms (E/T ratio: 1.01 and 1.14). Results from 1H NMR spectroscopy agree well with S/V ratios of alkaline nitrobenzene oxidation and E/T ratios of ozonation products. In conclusion differences in guaiacyl lignin and guaiacyl-syringyl lignin do not exactly reflect taxonomical differences, as reported in previous articles. It was found that guaiacyl-syringyl lignin is not necessarily linked to the presence of vessels. 相似文献
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木质素生物降解与生物制浆的研究现状分析 总被引:11,自引:0,他引:11
综述了木质素生物降解与生物制浆的研究现状 ,包括木质素降解代谢产物和降解途径与机制的研究、参与木质素降解的酶及其作用机制的研究、木腐菌对木材和木质素降解能力的研究以及高效降解木质素的生物制浆用优异菌株的筛选。对木质素生物降解与生物制浆的研究进行了展望。结果表明 :生物制浆由于既节省能源又有环境友好的特性而具有毋庸置疑的应用前景 ,在我国加强木质素生物降解和生物制浆的研究是势在必行的 ,这对于保护环境 ,缓解能源危机以及制浆造纸业的可持续发展都具有重要的意义。 相似文献
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在介绍木质素结构的基础上 ,从降解木质素的菌种及主要酶、产酶的条件 ,分析了真菌降解木质素的研究现状 ,介绍了真菌降解木质素及其酶的应用 ,并提出了存在的问题及发展方向 相似文献
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竹材预水解过程木质素迁移行为研究 总被引:1,自引:0,他引:1
通过分析竹片在预水解过程中的表面形貌及化学组成变化,研究木质素在竹材水解过程中的迁移行为。结果表明,在竹片预水解过程中,竹片内部的木质素类物质会逐渐迁移至竹片的表层和表面。竹片表层物质的FT-IR图显示,木质素特征峰随着水解程度的提高不断增强,而半纤维素特征峰则逐渐消失;竹片表层物质的XPS图显示,水解至120 min时表层物质的C1(C—C/C—H)含量较竹原料显著增加,从24.0%上升至45.5%,C2(C—O)含量明显减小,从35.5%下降至24.3%,O/C从0.43降低至0.34;水解20 min时表层木质素含量略低于竹片平均木质素含量,超过20 min后表层木质素含量均高于竹片平均木质素含量,而且其差值逐渐上升,水解120 min时,表层木质素为43.3%,竹片平均木质素为26.5%。 相似文献