基于电化学方法研究猪粪堆肥过程溶解性有机物电子转移能力演变规律

堆肥水溶性有机物(Dissolved organic matter,DOM)是堆肥有机质中最活跃的部分,而具有氧化还原能力的官能团使得DOM能够作为电子穿梭体促进微生物与电子受体间的电子传递。本研究提取了8个不同阶段堆肥样品的DOM,利用电化学方法,以2,2'-联氮双(3-乙基苯并噻唑啉-6-磺胺)二铵盐(ABTS)和敌草快农药(DQ)作为介导剂,工作电压设为0.61 V/~-0.49 V,分别测定电子供给能力(Electron donating capacity,EDC)和电子接受能力(Electron accepting capacity,EAC)。同时结合三维荧光光谱、红外光谱和元素分析等方法阐明DOM结构组分变化,并探讨其变化对电子转移能力的影响。结果表明,堆肥DOM的EDC从堆肥1 d的16.850μmol e~-/(g C)增加至43 d的22.077μmol e~-/(g C),EAC从堆肥1 d的1.866μmol e~-/(g C)降至43 d的1.779μmol e~-/(g C)。三维荧光光谱分析结果表明,在堆肥过程中类腐殖质组分含量逐渐增多,类蛋白组分逐渐减少,表明堆肥过程类腐殖质组分的形成对DOM的ETC起重要的贡献作用。红外光谱显示堆肥过程中DOM含量较高的羟基和羧基变化不显著,对电子转移能力无明显贡献。元素分析结果表明,DOM中氧元素含量随着堆肥进行而增加,含硫基团是电子转移能力的贡献基团。     

堆肥过程不同分子量水溶性有机物电子转移能力的演变及影响因素

利用超滤技术、电化学方法和光谱技术, 以堆肥水溶性有机物的不同分子量(MW)组分为研究对象, 分析在堆肥过程中不同分子量水溶性有机物(DOM)的组成特征、结构演变和电子转移能力变化的影响因素.结果表明, 类蛋白物质主要存在于堆肥前期的DOM(MW<1 kDa)中, 随着堆肥的进行, 类蛋白物质不断降解, 类富里酸物质持续合成, 堆肥后期类蛋白物质被完全降解, 类富里酸物质成为DOM(MW<1 kDa)主要的荧光组分.类腐殖物质是DOM(MW=1～3 kDa)、DOM(MW=3～5 kDa)和DOM(MW>5 kDa)的主要荧光组分, 堆肥过程中类腐殖质物质在3种不同分子量组分的变化各不相同, 但是堆肥后期类腐殖质物质在3个不同分子量组分的含量均高于堆肥初期. 堆肥过程中DOM(MW<1 kDa)的电子供给能力(EDC)呈降低趋势, 而电子接受能力(EAC)呈升高趋势; DOM(MW>5 kDa)的EDC在堆肥过程中呈上升趋势, 而EAC则无明显的变化规律.DOM(MW=1～3 kDa)和DOM(MW=3～5 kDa)的EDC和EAC在整个堆肥过程无明显变化规律.不同分子量组分堆肥DOM 的EAC受控于堆肥过程木质素降解产物的含量, 而其EDC变化与荧光参数和紫外参数无明显关系.     

石墨炭负载单原子铁催化剂非均相还原NO的微观作用机理：DFT研究

基于密度泛函理论和经典过渡态理论,探究了石墨炭负载单原子Fe催化剂(Fe/G)异相还原NO的微观机理,并对催化剂失活原因进行分析。结果表明,基于E-R机理,NO还原反应依次经历了N₂O形成与释放、N₂形成与释放四个阶段。而基于L-H机理,NO还原反应主要经历了N₂形成与释放两个阶段。在E-R机理作用下,NO分子以N,O-down结构吸附在Fe原子上发生的NO还原反应的控速步骤能垒值仅为15.5 kJ/mol,小于其余路径控速步骤能垒值。由能垒角度分析,Fe原子上残留的活性氧被还原的能垒值高于NO还原生成N₂的能垒值。NO分解后残留在Fe原子表面的活性氧抑制了NO的吸附与还原,Fe原子活性位的缺失导致催化剂的失活,单原子Fe的存在促进了NO还原反应的进行。由动力学角度分析,随着反应温度的升高,NO还原速率较活性氧转移速率提升更为显著。     

垃圾填埋初期水溶性有机物电子转移能力特征研究

为了阐明填埋垃圾初期水溶性有机物( DOM)电子转移能力的演变规律及影响因素,采集不同深度填埋垃圾并提取DOM,以希瓦氏菌MR-1和柠檬酸铁( FeCut)分别作为电子供体和电子受体,测定DOM的电子供给能力( EDC)、电子接受能力( EAC)和电子穿梭能力( ESC),采用光谱分析技术对电子转移能力的3种影响因素进行解析。结果表明,DOM中类腐殖质物质和类蛋白物质既能够作为电子供体传递出自身携带的电子,又可以作为电子受体接受微生物供给的电子。随着垃圾填埋的进行,DOM的电子供给能力和电子接受能力均先升高后降低,而电子穿梭能力持续增强。类蛋白物质是填埋初期 DOM 的主要成分,其含量决定DOM的电子供给能力和电子接受能力的演变。随着填埋时间的延长,类蛋白物质的降解是DOM的电子接受能力和电子供给能力降低的主要原因。 DOM反复氧化还原过程中光谱特征和参数变化规律显示DOM的电子穿梭能力主要源于DOM中类腐殖质物质。在填埋垃圾降解和腐殖化过程中,DOM中类腐殖质物质不断合成,致使其电子穿梭能力不断增强。     

Au／Fe2O3／Al2O3催化剂上丙烯选择催化还原NO

以浸渍法制备的Fe2O3/γ-Al2O3为载体,采用均相沉积沉淀方法制备了Au/Fe2O3/Al2O3催化剂.该催化剂在丙烯选择催化还原NO反应中显示出很好的低温催化活性,300℃时NO被选择还原为N2的转化率可达43%,而在Au/Al2O3催化剂上,NO的转化率仅为21%.水蒸气的加入对催化剂活性的影响较小.X射线衍射结果表明,Au和Fe2O3高度分散在Al2O3载体上.吸附氢气的程序升温还原结果表明,Au与Fe2O3之间存在着强相互作用,Au的存在促进了Fe2O3的还原,Au和Fe2O3之间的协同作用可能是Au/Fe2O3/Al2O3催化剂在丙烯选择还原NO反应中具有较高低温催化活性的原因之一.     

不同亲水性探针分子在金电极上硫醇自组装跨膜动力学研究

采用扫描电化学显微镜测定了不同亲水性氧化还原电对在硫醇修饰的金电极表面上的异相电子转移速率常数. 分别选择铁氰化钾[K3Fe(CN)6]和N,N,N',N'-四甲基-1,4苯二胺(TMPD)作为氧化还原探针,根据得到的反馈曲线拟合出异相电子转移速率常数. 比较这些速率常数可以看出, 修饰层对疏水性的TMPD分子显示出更好的穿透性. 通过一个简单的模型可以解释TMPD的穿透过程, 在TMPD电子隧穿的前后存在着单层膜和水溶液间的快速平衡, 而隧穿作为决速步骤, 其表观速率常数也比K3Fe(CN)6的大. 通过计算得到TMPD的隧穿因子β为1.2/CH2.     

AOT微乳液中通过水化电子产额调控合成BaSO_4纳米纤维

通过γ-辐照含有K2S2O8和BaCl2的二(2-乙基己基)琥珀酸酯磺酸钠(AOT)反相微乳液,将S2O82-通过辐射还原实现了SO42-的原位缓释,从而成功制备出BaSO4纳米纤维单晶,并进一步制得多层次的纳米纤维束结构.在此基础上,通过改变水与表面活性剂物质的量之比(ω值)、改变钡盐阴离子和在微乳液连续相添加芳香化合物等手段来调节水化电子(e-aq)产额,控制微乳液水池中S2O82-的还原和SO42-的缓释速率,成功实现了对BaSO4纳米粒子形貌的调控:随着ω值的增加或剂量率的增加,e-aq产额增加,从而加快了SO42-的释放,不利于BaSO4纳米纤维的生成;采用Ba(NO3)2为钡源时,NO3-能有效地降低e-aq产额和S2O82-的还原速率,因而在较高的剂量率和较高ω值下能得到BaSO4纳米纤维;在微乳液油相中加入甲苯来捕获油相中过量电子(e-oil),降低e-aq产额,从而在较高的剂量率下得到BaSO4纳米纤维.研究结果表明:通过e-aq产额调控纳米粒子形貌的机理在BaSO4纳米粒子的制备中得到很好体现.     

磁性光催化剂BiVO_4/Fe_3O_4降解亚甲基蓝的研究

本文用超声法将磁基体Fe3O4与BiVO4复合,制备了易于固液分离的磁性可见光催化剂BiVO4/Fe3O4,采用X射线衍射(XRD)、透射电子显微镜(TEM)等手段对样品的结构和形貌进行表征。以亚甲基蓝为降解对象,考察了BiVO4/Fe3O4的可见光催化活性,并研究了光催化体系中光催化剂用量、亚甲基蓝初始浓度、溶液的pH值、电子受体的存在对光催化过程的影响。结果表明,催化剂的最佳用量为2.0g/L,亚甲基蓝最佳初始浓度为10mg/L,溶液的最佳pH值为11,加入电子受体K2S2O8时,亚甲基蓝几乎完全降解。催化剂回收后连续使用3次,降解率仍然大于80%。     

Ru-Fe二元金属纳米粒子对氧还原的电催化性能

在1,6-己二醇溶剂中,以Ru3(CO)12和Fe3(CO)12为原料,采用低温回流方法合成了Ru-Fe纳米粒子催化剂。利用扫描电镜(SEM)、X射线衍射仪(XRD)和电化学技术表征了催化剂的物理特征和电催化性能.催化剂粉末以六方结构的Rux簇为主相,呈现出高度均匀而聚集的纳米颗粒特征.在0.5mol/L H2SO4溶液中,Ru-Fe催化剂对氧还原反应(ORR)的电催化活性高于Rux,主要归因于d电子从Ru原子到Fe原子的转移过程.     

负载型铁系钙钛矿催化剂的研究

钙钛矿型复合氧化物是还原烟气中 SO2 的有效催化剂 .对于钙钛矿催化剂的负载化已有过研究报道 [1,2 ] ,但仅限于活性盐溶液对载体或载体改性后的直接浸渍 ,效果并不很好 .本文用溶胶 -凝胶法制备了负载型 Fe系钙钛矿催化剂 ,取得了良好效果 .1　实验部分1 .1　催化剂制备和表征　将工业载体 γ- Al2 O3 破碎筛分为 40～ 6 0目 ,在 6 0 0℃下煅烧 3 h进行活化处理 ,而后分别采用以下 3种方法制备 :(1 )配制适当浓度的 La(NO3 ) 3 和 Fe(NO3 ) 3 溶液 ,用n(La3 + )∶ n(Fe3 + ) =1∶ 1的混合溶液直接对 γ- Al2 O3 浸渍 ,过滤后于 1 2 …     

碳笼氧化物的结构和谱学性质

碳笼氧化物对碳笼的官能团化研究具有重要意义，因而激起了人们广泛的研究兴趣。本文对碳笼氧化物C₆₀O_n、C₇₀O_n、C₇₆O_n、C₇₈O_n及C₈₀O_n的结构、电子光谱、红外光谱及核磁共振谱的研究进展进行综合评述。介绍了国内外近十几年来众多研究小组的工作，并结合作者本人在此方面的理论研究成果，进一步探索碳笼氧化物的结构特点以及光谱性质的规律性。在对C₆₀及C₇₀氧化物研究结果与实验符合的基础上，预测高碳笼氧化物的结构和光谱。     

Syntheses and spectral properties of longwave absorbing and fluorescing substrates for the direct and continuous kinetic assay of carboxylesterases,phosphatases, and sulfatases

Syntheses, absorption and fluorescence properties for a series of new enzyme substrates are described, which are derived from 7-hydroxycoumarins possessing electron-withdrawing substituents in position 3. The new substrates are advantageous over existing ones in that they exhibit longwave absorption and fluorescence maxima as well as largeStokes' shifts. In addition, theirpK _a values, which are usually between 6.0 and 7.0, allow the direct and continuous kinetic assay of hydrolases such as esterases, phosphatases, and sulfatases.

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Synthesen und spektrale Eigenschaften langwellig absorbierender und fluoreszierender Substrate für die direkte und kontinuierliche kinetische Bestimmung von Carboxylesterasen, Phosphatasen und Sulfatasen

Zusammenfassung Die Synthesen und Absorptions- sowie Fluoreszenzspektren einer Reihe neuer Enzymsubstrate werden beschrieben, welche von 7-Hydroxycumarinen mit elektronenziehenden Substituenten in 3-Stellung abgeleitet sind. Die neuen Substrate bieten gegenüber bisherigen den Vorteil langwelliger Absorptions- und Fluoreszenzmaxima sowie großerStokes-Verschiebungen. Die niedrigenpK _s -Werte, welche zwischen 6 und 7 liegen, erlauben weiters eine direkte und kontinuierliche kinetische Bestimmung von Hydrolasen vom Typ der Esterasen, Phosphatasen und Sulfatasen.

     

Diffuse reflection FTIR spectral database of dyes and pigments

24 pigments commonly used in art have been characterized by diffuse reflection infrared spectroscopy (DR). All of the compounds have also been characterized by means of infrared absorption spectroscopy to demonstrate the reliability of the DR technique. This is the first record of the use of this technique as an analytical tool in conservation science, and the results appear to be promising for the identification of unknown pigments used on historical and artwork artifacts. Although the DR technique used here is not nondestructive, it can still be usefully applied to the analysis of artwork since it requires only a very small quantity of sample for analysis.     

Synthesis and structural studies of complexes of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with substituted chalcones

Complexes of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with 3-(2-pyridyl)-1-(2-hydroxy phenyl)-2-propen-1-one (PHPO), 3-(1-naphthyl)-1-(2-hydroxy phenyl)-2-propen-1-one (NHPO) and 3-(3,4-dimethoxy phenyl)-1-(2-hydroxy phenyl)-2-propen-1-one (DMPHPO) have been synthesized and characterized by analytical, conductivity, thermal, magnetic, infrared, electronic and electron spin resonance data. Based on analytical data the stoichiometry of the complexes has been found to be 1 : 2. The conductivity data show that all these complexes are non-electrolytes. The infrared spectral data indicate that the ligand PHPO acts as uninegative tridentately towards Co(II) and Ni(II) and bidentately with Cu(II), Zn(II) and Cd(II). Ligands like NHPO and DMPHPO act as uninegative bidentately with all the metal ions. The electronic spectral data suggest that all the Co(II) complexes and Ni(II) of PHPO complex are octahedral and all the Cu(II) and Ni(II) of NHPO and DMPHPO complex are square-planar. The complex of Zn(II) and Cd(II) are tetrahedral. ESR parameters of Cu(II) complexes have been calculated and relevant conclusions have been drawn with respect to the nature of bonds present in them.     

The synthesis and characterization of norbornylsilasesquioxanes

Norbornene reacts with trichlorosilane to generate norbornyltrichlorosilane in high yield. The slow hydrolysis of norbornyltrichlorosilane in acetone yields incompletely condensed norbornyl-silasesquioxanes. The compound C₄₂H₇₀O₁₁Si₆ can be isolated from this reaction. On the basis of elemental analyses, ¹H, ¹³C and ²⁹Si NMR, mass spectroscopy, infrared spectroscopy, and crystallographic analysis, C₄₂H₇₀O₁₁Si₆ is formulated as [(C₇H₁₁)₆Si₆O₇(OH)₄], with the Si₆O₇ framework being composed of two perpendicular Si₄O₄ planes sharing an edge. [(C₇H₁₁)₆Si₆O₇(OH)₄] is a putative model of vicinal [Si(OH)]₂ sites on the surface of partially dehydroxylated silica.     

The fluorescence of ellagic acid and its borax complex

The absorption and fluorescence properties of the plant phenol ellagic acid have been studied in alcohol and aqueous solutions. Fluorescence is weak in all kinds of solvents, but is greatly enhanced by addition of borax. The resulting complex emits much more intensely in methanol than in water solution. UV and fluorescence data reveal that the complex formed in methanol is different from the complex formed in aqueous solution. The enormous fluorescence enhancement of ellagic acid by borax offers a simple method for the visualization and quantification of the potent anti-mutagen ellagic acid as well as a fluorimetric method for the determination of boron.The IUPAC name for ellagic acid is 2,3,7,8-tetra-hydroxy[1]benzopyrano[5,4,3—c,d,e][1]-benzopyran-5,10-dione.     

L-谷氨酸桥连的卟啉二联体配体及其铜配合物的合成、表征和性质研究

合成了未见报道的L-谷氨酸桥连的卟啉二联体配体及其铜的金属配合物, 并用红外光谱, 电子吸收光谱, 核磁氢谱, 元素分析和质谱等对化合物的结构加以确认, 研究了配体和金属配合物的CD, 拉曼光谱和荧光光谱的变化. 结果显示在配体中没有出现劈裂的Cotton效应, 而铜配合物中出现了劈裂的正负Cotton效应, 配体的荧光强度强于铜配合物的荧光强度, 在拉曼光谱中, 由于卟啉分子平面的对称性由D_2h变为D_4h群及其铜离子d轨道的电子效应, 在卟啉配体和铜配合物之间的拉曼光谱有很大差别.     

四(对-硝基苯基)卟啉配合物的红外和拉曼光谱

本文研究了四(对-硝基苯基)卟啉及其Cr(Ⅲ)、Mn(Ⅲ)、Fe(Ⅲ)、Co(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Zn(Ⅱ)配合物的3500～220cm~(-1)的红外光谱和1700～100cm~(-1)的拉曼光谱.谱带归属表明,～250cm~(-1)谱带是M—N伸缩振动和卟啉环变形振动的复合振动.金属敏感带出现在～1600、～1582、～1547、～1284、～1190、～355和～245cm~(-1)处,其中二价金属配合物金属敏感带频率按Ni>Co>Cu>Zn顺序递减.用金属半径和d_x~2 y~2电子排斥作用解释了金属敏感带变化规律.     

Synthesis and Reactions of Polynuclear Heterocycles: Azolothienopyrimidines and Thienothiazolopyrimidines

We prepared a thieno[2,3-d]pyrimidine compound fused with a thiazolo ring to produce biologicaly active compounds. In a one-step reaction, 2-arylmethylene derivative (3) was prepared via the reaction of a ternary mixture of 2-thioxo-1,2,3,4-tetrahydrocyclohepteno[4,5]thieno[2,3-d]pyrimi-dine-4-one (2), cloroacetic acid, and a proper aldehyde. The reaction of 2 with 3-chloropent-2,4-dione in ethanolic potassium hydroxide yielded the S-acetylacetone derivative 4e. The latter compound reacted with hydrazine hydrate and phenyl hydrazine to give 2-pyrazolthio derivatives 8a,b, respectively. Compound 4e also underwent cyclization on boiling with acetic anhydride/pyridine solution to form 2-acetyl-3-methyl thiazolo[3,2-a]cyclohepteno[4,5]thieno[2,3-d] pyrimidine-5-one (9). To support the structure 9, it gave a characteristic reaction for the 2-acetyl group. The 2-methylthio derivatives 4a underwent further alkylation at N₃ to give 6a,b. The purpose of the synthesis of thienopyrimidine derivatives is due to high biological activities. The 4-oxo-thienopyrimidine derivatives acted as inhibitors of adenosine kinase, platelet aggregation, antilukemia, and anticancer activities.     

Preparation and investigation of the crystals formed in the buckminsterfullerene-tetraselenotetracene-carbon disulfide system

Crystals containing up to 30 wt. % CS₂, according to the data of IR and X-ray photoelectron spectroscopy, were isolated from the C₆₀-TSeT-CS₂ (TSeT is tetraselenotetracene) system. The unusually high concentration of carbon disulfide results in the complete sublimation of the crystals at a relatively high temperature (520 °C). The electron energy loss spectra of the crystals obtained were measured and analyzed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 845–848, May, 1995.This work was financially supported by the Russian Foundation for Basic Research (Projects No. 93-03-18002, 93-03-18705, and 93-03-5650).