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高效液相色谱法测定菌群降解纤维素产物中的糖、有机酸和醇 总被引:1,自引:0,他引:1
采用硫酸除钙和调节pH的样品预处理方法,利用高效液相色谱对菌群降解纤维素发酵液中的糖、有机酸和醇3类物质进行分析,待测组分与培养基成分能够得到有效分离。从菌群降解纤维素发酵液中检出纤维二糖、葡萄糖、乙醇、丁醇、甘油、乙酸与丁酸并进行了定量分析,7种组分的检出限范围为0.10~2.00 mg/L,线性相关系数均大于0.9996,线性范围为0.020~1.000 g/L,回收率为85.41%~115.60%,相对标准偏差(RSD)为0.22%~4.62%(n=6)。该方法准确可靠,可实现对菌群降解纤维素发酵液中糖、醇和有机酸的同时准确测定。 相似文献
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用溶胶-凝胶法制备Ce-Mn储氧材料,并于该储氧材料上分别负载光催化剂TiO2 和贵金属Pt制备出Pt-TiO2/CeO2-MnO2复合催化剂. 用X射线衍射、 X射线能谱分析、程序升温还原和漫反射紫外-可见光谱等技术对复合催化剂进行了表征,并以光热催化降解气相苯评价了复合催化剂的活性. 结果表明, Mn分别进入到TiO2和CeO2的晶格中形成固溶体; Pt均匀分散在复合催化剂表面; Ce-Mn储氧材料在250 ℃下具有较好的储氧性能; 复合催化剂对紫外及可见光的吸收较强; 1.6%Pt-40%TiO2/CeO2-MnO2复合催化剂的活性较高,光热催化10 h时,苯降解率可达94.5%. 相似文献
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沸石分子筛吸附和催化降解亚硝胺 总被引:9,自引:0,他引:9
综述了近年来国内外在使用沸石和介孔分子筛吸附和催化分解以及检测亚硝胺方面的新进展.亚硝胺属于强致癌物,是吸烟导致癌症的重要原因.本文剖析了沸石对亚硝胺的选择性吸附以及大体积亚硝胺在小微孔沸石上的"嵌入式"吸附模式,探讨了沸石在气相和液相中吸附挥发性亚硝胺的规律和影响因素;研究了介孔分子筛材料对于催化降解烟草特有亚硝胺的高活性,阐述了修饰金属氧化物对于提高沸石吸附或催化分解亚硝胺能力的促进作用,并展望消除亚硝胺污染功能新材料的发展方向. 相似文献
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ZnO-SnO2纳米复合氧化物光催化剂催化降解对硝基苯胺 总被引:12,自引:0,他引:12
采用共沉淀法合成了n(Zn)/n(Sn)=2的ZnO-SnO2纳米复合氧化物光催化剂,并采用X射线衍射(XRD)、紫外-可见(UV-Vis)漫反射吸收光谱、透射电子显微镜(TEM)和N2物理吸附等方法对在500~1300 ℃焙烧不同时间制得的ZnO-SnO2纳米复合氧化物的物相组成、光吸收性能、晶粒尺寸、颗粒大小、比表面积和孔体积进行了表征. 以对硝基苯胺为模型化合物,对ZnO-SnO2复合氧化物的光催化活性进行了评价,考察了催化剂焙烧温度和焙烧时间对其催化活性的影响. 结果表明,在700 ℃焙烧2 h制得的ZnO-SnO2纳米复合氧化物具有最高的光催化活性. 相似文献
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以无机铁盐和邻苯二胺为基础原料,经铁基螯合前驱体热解反应,制备出Fe-N-C复合催化剂.经扫描电镜观察,带有折褶的碳微纳米片相互交迭,形成银耳状的三维自支撑结构.氮气吸脱附测试表明此结构富含微孔和介孔,比表面积可达290 m2/g.通过X射线衍射(XRD)确证石墨化C和多晶Fe3C作为催化剂主相存在, X射线光电子能谱(XPS)进一步揭示N原子主要以石墨N和吡啶N形式掺杂到C骨架中.电化学测试表明银耳状Fe-N-C复合催化剂在碱性条件下催化氧还原反应为四电子过程,其催化活性可媲美商业Pt/C催化剂.经过2000次氧还原测试后,催化极限电流衰减小于5%,并且半波电势仅负移5 mV(商业Pt/C催化剂负移35 mV),表现出优异的氧还原催化稳定性. 相似文献
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基于具有"反应器颗粒技术(RGT)"特征的Ziegler-Natta/茂金属复合催化剂(MgCl2/TiCl4/racEt(Ind)2ZrCl2),以三乙基铝(AlEt3,TEA)和烷基铝氧烷(MAO)分别作为Ti和Zr 2种催化剂组分的助催化剂,利用TEA对茂金属Zr中心在丙烯均聚反应中的阻聚作用,以及乙烯对"失活"中心的活性复原,实现了复合催化剂中茂金属Zr中心在聚丙烯催化合金(丙烯均聚+乙烯/丙烯共聚)过程中的"可逆失活".基于这种方法,以MgCl2/TiCl4/rac-Et(Ind)2ZrCl2为催化剂,TEA/MAO为助催化剂,通过一步法(催化剂和助催化剂一次加入)制备了新型聚丙烯催化合金,聚丙烯基体(PP)选择性地由Ti金属中心生成,而乙丙共聚物(EPR)则有相当大的比例由茂金属Zr中心生成.与完全由Ziegler-Natta催化剂所产生的聚丙烯催化合金相比,新型合金中的EPR共聚序列结构更加无规,同时EPR保持在PP基体中均匀分散. 相似文献
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Ismail Marzuki Ruzkiah Asaf Mudian Paena Admi Athirah Khairun Nisaa Rasheed Ahmad Mudyawati Kamaruddin 《Molecules (Basel, Switzerland)》2021,26(22)
Every petroleum-processing plant produces sewage sludge containing several types of polycyclic aromatic hydrocarbons (PAHs). The degradation of PAHs via physical, biological, and chemical methods is not yet efficient. Among biological methods, the use of marine sponge symbiont bacteria is considered an alternative and promising approach in the degradation of and reduction in PAHs. This study aimed to explore the potential performance of a consortium of sponge symbiont bacteria in degrading anthracene and pyrene. Three bacterial species (Bacillus pumilus strain GLB197, Pseudomonas stutzeri strain SLG510A3-8, and Acinetobacter calcoaceticus strain SLCDA 976) were mixed to form the consortium. The interaction between the bacterial consortium suspension and PAH components was measured at 5 day intervals for 25 days. The biodegradation performance of bacteria on PAH samples was determined on the basis of five biodegradation parameters. The analysis results showed a decrease in the concentration of anthracene (21.89%) and pyrene (7.71%), equivalent to a ratio of 3:1, followed by a decrease in the abundance of anthracene (60.30%) and pyrene (27.52%), equivalent to a ratio of 2:1. The level of pyrene degradation was lower than that of the anthracene due to fact that pyrene is more toxic and has a more stable molecular structure, which hinders its metabolism by bacterial cells. The products from the biodegradation of the two PAHs are alcohols, aldehydes, carboxylic acids, and a small proportion of aromatic hydrocarbon components. 相似文献
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人血红蛋白及其三硝基甲苯加合物的高效液相色谱分离 总被引:1,自引:0,他引:1
介绍了采用反相大孔径C4柱分离血红蛋白(Hb)的新的高效液相色谱(HPLC)条件,流动相采用乙腈-水-三氟乙酸,在梯度洗脱方式下,对Hb中的血色素(heme)、α-和β-链以及未解离的球蛋白进行了分离,速度快且洗脱完全,并用于三硝基甲苯(TNT)-Hb加合物的分离。结果在体外实验发现了TNT-Hb加合物的形成,其水平为204pmol/mgHb。 相似文献
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《Analytical letters》2012,45(10):675-681
Abstract The characteristic p.m.r. signal at τ 8.4–8.6 given by the CH3-C group of a pyruvic acid ketal (1-carboxyethylidene derivative)may be used to demonstrate the presence of such a substituent in polysaccharides. Similar signals are given when the pyruvic acid ketal is methylated or reduced. The method is convenient for monitoring purification procedures and chemical transformations of polysaccharides such as are involved in structural studies. In certain cases the molar ratio of pyruvic acid may be estimated. 相似文献
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Chen Li Zheng-Xi Zhou Xiao-Qiang Jia Yu Chen Jiao Liu Jian-Ping Wen 《Applied biochemistry and biotechnology》2013,171(7):1715-1725
A highly efficient oil-degrading bacteria JZX-01 was isolated from the oil-contaminated soil of the seacoast near the Boxi Offshore Oil Field of China. Morphological, physiological, and 16S rDNA gene sequence analyses indicated that JZX-01 was assigned to the genus Rhodococcus sp. This strain decomposed 65.27?±?5.63 % of the crude oil in 9 days. Gas chromatography–mass spectrometry analysis showed that even the long-chain hydrocarbons (C31–C38) and branched alkanes (pristine and phytane), which were regarded as the stubborn ones, could be degraded. Further study showed that the bacteria still has good oil degradation ability at low temperatures as well as under high salt conditions. Moreover, JZX-01 was found to have a biosurfactant-producing capacity, which significantly favors the surface tension reduction and crude oil degradation. The promising isolated strain Rhodococcus sp. JZX-01 could be further used for the bioremediation of oil-polluted soil or seawater in a wide range of temperatures and high salt conditions. 相似文献
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Dan LIU Gu YUAN 《中国化学快报》2005,16(10):1330-1332
DNA-photocleavage agents have generated considerable attention in chemistry,biology and medicine1,2,because their DNA-cleavage activities can be easily controlled by photoirradiation.In the past decade,several DNA-cleavage agents have been successfully attached to polyamide3,4,to obtain new conjugates with higher and specific DNA-cleavage activities.Most of them contain only one photocleavage group to induce single-strand breaks,and the conjugates inducing double-strand breaks have been ra… 相似文献
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Our work emphasized on synthesizing and characterizing neutral mononuclear copper(II) complexes with second generation fluoroquinolone drug ciprofloxacin (CFL) and some bipyridine derivatives (An) of type [Cu(CFL)(An)Cl] · 2H2O. The DNA binding free energies were evaluated by studying the effect of salt concentrations on DNA binding. DNA interactions were investigated by using DNA melting temperature studies, viscosity measurements, absorption titration, and gel electrophoresis experiments. Also superoxide dismutase (SOD)‐like activity (IC50 values) and antibacterial activity of metal complexes were studied. To validate the proper mechanistic pathway for plasmid DNA cleavage, gel electrophoresis experiments were carried out in presence of radical scavenging agents. The bactericidal activity of metal complexes was evaluated in terms of colony forming unit. 相似文献
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Reactions of [Ru]Cl ([Ru]={Cp(PPh3)2Ru}; Cp=cyclopentadienyl) with three alkynyl compounds, 1 , 5 , and 8 , each containing a cyclobutyl group, are explored. For 1 , the reaction gives the vinylidene complex 2 , with a cyclobutylidene group, through dehydration at CδH and CγOH. With an additional methylene group, compound 5 reacts with [Ru]Cl to afford the cyclic oxacarbene complex 6 . The reaction proceeds via a vinylidene intermediate followed by an intramolecular cyclization reaction through nucleophilic addition of the hydroxy group onto Cα of the vinylidene ligand. Deprotonation of 2 with NaOMe produces the acetylide complex 3 and alkylations of 3 by allyl iodide, methyl iodide, and ethyl iodoacetate generate 4 a – c , respectively, each with a stable cyclobutyl group. Dehydration of 1 is catalyzed by the cationic ruthenium acetonitrile complex at 70 °C to form the 1,3‐enyne 7 . The epoxidation reaction of the double bond of 7 yields oxirane 8 . Ring expansion of the cyclobutyl group of 8 is readily induced by the acidic salt NH4PF6 to afford the 2‐ethynyl‐substituted cyclopentanone 9 . The same ring expansion is also seen in the reaction of [Ru]Cl with 8 in CH2Cl2, affording the vinylidene complex 10 , which can also be obtained from 9 and [Ru]Cl. However, in MeOH, the same reaction of [Ru]Cl with 8 affords the bicyclic oxacarbene complex 12 a through an additional cyclization reaction. Transformation of 10 into 12 a is readily achieved in MeOH/HBF4, but, in MeOH alone, acetylide complex 11 is produced from 10 . In the absence of MeOH, cyclization of 10 , induced by HBF4, is followed by fluorination to afford complex 13 . Crystal structures of 6 and 12 a ′ were determined by single‐crystal diffraction analysis. 相似文献
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Jones AM Liu G Lorion MM Patterson S Lebl T Slawin AM Westwood NJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(20):5714-5718
Oxidative cleavage of internal double bonds in polycyclic systems can give access to compounds containing medium- to large-sized rings. In this example, the nine- and ten-membered ring containing compounds that resulted from the mCPBA-mediated (mCPBA=meta-chloroperoxybenzoic acid) oxidative cleavage reaction were shown to exhibit atropisomerism. The reaction of the polycyclic system with catalytic amounts of ruthenium tetraoxide followed by diol cleavage achieved the same synthetic goal. Use of the Nishiyama-Beller ruthenium-based catalysts enabled the synthesis of optically-enriched samples, providing the first example of an atropselective oxidative cleavage reaction. 相似文献