纳米TiO2异相光催化降解2,6-二甲酚中间过程的UV吸收光谱和荧光光谱示踪研究

用半导体纳米材料(如TiO₂,SnO₂,CdS等)进行光降解消除污染物因其能最大限度利用太阳能和降解完全(有机质最终全部转化为CO₂,H₂O等)以及降解速率高的特点被认为是环境科学的新领域。异相光催化降解是有机物作为电子供体捕获TiO₂表面光生空穴自身被氧化降解的过程,因TiO₂价带空穴所具有强的氧化性,一般有机物都可进行光化学反应^[1]。这一过程总是以一系列的中间反应步骤所构成,中间体形成的峰形动力学曲线及其异于原初态的光谱特性对揭示光催化降解动力学过程至为重要。本文主要对2,6-二甲酚-纳米TiO₂悬浮体系光降解动态分子光谱进行示踪研究。     

铋掺杂介孔二氧化钛的制备及光催化动力学

以介孔分子筛(KIT-6)为载体,采用溶液浸渍法合成了铋(Bi)掺杂的介孔二氧化钛(TiO₂)光催化剂。利用XRD、TEM、SEM、XPS、N₂吸附-脱附法和拉曼光谱法等技术手段对材料的结构和形貌进行表征。通过紫外-可见吸收光谱法考察了催化剂对罗丹明B光催化降解效率,进一步考察了Bi的掺杂量对光催化反应速率的影响,并对光催化降解动力学进行了初步研究。结果表明,Bi掺杂的介孔TiO₂具有较窄的孔径分布(3~4 nm),而且吸收范围扩展到可见光区,其光催化活性明显高于商品TiO₂(P25)。随之Bi掺杂量的提高,反应速率常数也增大,其光催化降解罗丹明B的反应均符合准一级动力学方程。     

Li+掺杂纳米TiO2的制备及其光催化性能研究

采用溶胶-凝胶法和浸渍法制备了Li⁺掺杂纳米TiO₂光催化剂,并用XRD和TEM等技术进行了表征;用pH值漂移法测量了催化剂的零电位pH值(pHpzc).结果表明,500℃煅烧制得的催化剂均为锐钛矿相;Li⁺的掺杂抑制了TiO₂粒子的生长,提高了催化剂的分散性;催化剂的零电位pH值为6.6—8.1,其值取决于Li⁺的浓度和掺杂方式.分别以紫外光和太阳光为光源,孔雀石绿和甲基橙为降解物评价了催化剂的光催化活性;并用气相色谱测试了污染物降解产生的CO₂的含量.结果显示,对孔雀石绿的降解,浸渍法和溶胶-凝胶法掺Li⁺都能有效提高TiO₂的光催化活性,但浸渍法比溶胶-凝胶法效果更好,催化活性最高的为浸渍法制备的5%(摩尔分数)Li⁺掺杂TiO₂,其在紫外光和太阳光下的光催化活性分别比纯TiO₂提高了6—8倍和9—10倍;对甲基橙的降解,除溶胶-凝胶法制备的3%(摩尔分数)Li⁺掺杂TiO₂能稍提高光催化活性外,其它Li⁺的掺杂都不同程度降低了TiO₂的光催化活性;随污染物降解率的增加,最终降解产物CO₂的含量增加.实验结果表明,Li⁺掺杂改变了催化剂表面的电荷状态从而改变了催化剂的零电位pH值是造成催化剂降解不同污染物具有不同催化活性的主要原因.     

BiOBr/g-C3N4 S型异质结无H2O2光-自芬顿高效催化降解RhB

通过焙烧-超声混合法成功地制备了BiOBr/g-C₃N₄S型异质结复合光催化剂。采用多种表征手段对样品物理属性进行了表征,包括X射线多晶粉末衍射仪(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、紫外可见漫反射光谱(UV-Vis DRS)。研究了所制备样品有/无Fe³⁺的光-自芬顿催化/光催化降解罗丹明B(RhB)性能。通过捕获实验确定了光催化反应中的主要活性物种,提出了光-自芬顿反应的降解机理。研究结果表明,BiOBr/g-C₃N₄S型异质结能原位生成H₂O₂,添加Fe³⁺后,H₂O₂被原位活化成活性物种且光生电流和载流子分离效率获得显著提高。该光-自芬顿过程能高效降解RhB,其反应速率常数为0.208 min^-1,约为无Fe³⁺光催化反应速率常数的5.3倍,在光-自芬顿循环使用过程中表现出良好的稳定性。Fe...     

新型杂多酸盐光催化降解亚甲基蓝染料废水

以水热自组装法合成的新型杂多酸盐[PMo₈V₆O₄₂][Co(Phen)₂][Him]₂·2H₃O·3H₂O(1),通过红外光谱、拉曼光谱、紫外-可见光谱、光电子能谱和X粉末衍射等技术手段进行表征。 以此物质为催化剂光催化降解亚甲基蓝染料废水。 分别讨论催化剂投加量、亚甲基蓝废水初始浓度、废水溶液酸度(pH)对亚甲基蓝降解率的影响。 实验结果表明:催化剂投加量为50 mg/L、亚甲基蓝初始浓度为4 mg/L、模拟废水溶液的初始pH=1、降解时间220 min时,废水降解率可达到99.2%。 光催化动力学分析显示,以合成杂多酸盐为催化剂光催化降解亚甲基蓝废水降解过程满足一级动力学方程,该一级方程反应速率常数为0.0144 min^-1,拟合常数为0.9918。 另外,此催化剂还表现出较好的重复使用性能,连续使用5 次后降解率仍为92.4%。     

LaNi1-xFexO3钙钛矿型氧化物的制备与光催化降解性能

通过溶胶-凝胶法制备系列LaNi_1-xFe_xO₃（x=0.05, 0.1, 0.2, 0.4, 0.6和0.8）钙钛矿型氧化物光催化材料,采用X射线衍射进行结构表征,以甲基橙的降解率作为催化剂活性的评价指标,探究了实验条件对光催化活性的影响。结果表明,少量掺杂Fe³⁺可提高LaNiO₃的光催化活性,在所有样品中LaNi_0.95Fe_0.05O₃的光催化活性最高;当催化剂用量为1.0 g﹒L^-1时,对浓度为10 mg﹒L^-1的甲基橙溶液的光催化效果最佳,可见光照射120 min的降解率高达98.9%,5次重复使用后的降解率仍可达84.6%,具有稳定高效的重复利用性。      

铕掺杂TiO2的制备及其可见光光催化性能研究

采用溶胶-凝胶法制备了不同铕(Eu)掺杂量的TiO₂纳米颗粒(Eu-TiO₂),利用透射电镜(TEM),X射线光电子能谱(XPS),X射线衍射(XRD)及紫外可见漫反射(UV-Vis DRS)等方法对Eu-TiO₂进行了物理特性的初步表征.结果表明:与未掺杂纳米TiO₂比较,Eu-TiO₂禁带宽度变窄,具有可见光光催化活性.在可见光下(λ≥420 nm)照射下,以光催化降解染料罗丹明B(Rhodamine B,RhB)为目标反应,探讨了Eu-TiO₂不同制备条件对RhB降解光催化活性的影响,优化得到制备高活性Eu-TiO₂最佳pH为3、掺杂比例(n_Eu/n_Ti)为0.05%、煅烧温度为500 ℃.研究了可见光照射下Eu-TiO₂降解RhB和无色有机小分子水杨酸(SA)光催化反应条件及降解特性,RhB的12 h深度氧化矿化率为60.2%,SA的8 h降解率达到100%.通过跟踪测定可见光下Eu-TiO₂光催化反应过程中氧化物种的变化,研究了可见光激发Eu-TiO₂光催化反应机理,表明其光催化反应主要涉及羟基自由基(·OH)历程.     

CuO-CoO-Cr2O3-K2O催化剂的表征及其低碳醇合成反应特性和本征动力学行为考察

本工作用TPR、TPD、XRD、TEM、SEM和物理吸附方法比较系统地表征了CuO-CoO-Cr₂O₃-K₂O催化剂的单组份、双组份及三组份及热失活催化剂的还原特性,热脱附特性、物理吸附特征、物相结构及其形貌特征,同时用考察宏观反应特性与本征动力学行为方法初步探讨了CO₂+H₂,CO+H₂和CO+CO₂+H₂体系反应特性和本征动力学特性,获得以下反应能被光催化、被p-DNB部分阻止及5的生成均表明反应经历了S_RN1机理。     

Fe对NaNbO3的晶格掺杂和同步异质结改性及其光催化性能

运用溶剂热法及继之的高温晶化法制备钙钛矿结构NaNbO₃,并在此基础上同步获得了NaNbO₃晶格内Fe³⁺的掺杂和NaNbO₃晶格外α-Fe₂O₃的异质结复合.观察到了同步改性NaNbO₃对水体罗丹明B（RhB）光催化降解效率的显著提升,最适Fe含量的改性NaNbO₃对罗丹明B 1 h内的降解率可达95%,表观一级动力学速率常数为改性前NaNbO₃的近7倍.运用X射线衍射（XRD）、扫描电子显微（SEM）、X光电子能谱（XPS）、光致发光（PL）光谱、低温N₂吸附-脱附（BET法）,电子自旋共振光谱（ESR）,紫外-可见漫反射光谱（DRS）及光致电流检测等表征和测量探明改性体系的组成及结构,并表明Fe³⁺对Nb⁵⁺的掺杂取代可通过杂质能级形成、电子和空穴捕获以及溶氧吸附的促进从而有利于对罗丹明B的光催化降解;适量α-Fe₂O₃晶格外复合改性NaNbO₃可通过NaNbO₃与α-Fe₂O₃异质结间电子的跃迁和流动提高复合催化剂的光量子效率.Fe对NaNbO₃晶格内外改性促活的实质可能在于光生载流子迁移的促进和对其复合的抑制.     

可漂浮CA/TiO2/RGO光催化剂的制备及其性能探究

首先利用氧化石墨烯(GO)改性TiO₂,然后以碳酸钙-碳酸钠为造孔剂，通过海藻酸钙(CA)固载TiO₂/GO制备CA/TiO₂/GO凝胶微球，最后该微球经抗坏血酸水浴还原GO,获得可漂浮CA/TiO₂/RGO微球作光催剂；并采用FT-IR、XRD、SEM、UV-Vis DRS以及TGA等测试手段对CA/TiO₂/RGO形貌及结构进行表征分析，初步探究CA/TiO₂/RGO对氨基黑10B降解性能和机理。结果表明：于30 mg/L氨基黑10B染料溶液中，投加CA/TiO₂/RGO光催剂浓度为1.84 g/L,220 min内CA/TiO₂/RGO对氨基黑10B的降解率可达80%,降解过程符合一级反应动力学模型，其光催化降解的主要活性物种是·O₂^-,而·OH和h⁺在本降解中起到作用相对较小。     

Excess Molar Enthalpies and Excess Molar Volumes of Binary Mixtures of Benzene and Alkanols with Quinoline

Molar excess enthalpies H _m ^E have been determined over the whole composition range for mixtures of benzene, methanol, ethanol, 1-propanol, 2-propanol and 1-butanol with quinoline at 298.15 K using a Thermometric flow calorimeter. The results reflect a strong H-bond association between an alkanol and quinoline which decreases with increasing length of the alkanol chain. The small H _m ^E for (benzene+quinoline) reflects the similarity of the two molecules. This revised version was published online in August 2006 with corrections to the Cover Date.     

Cr~(3+)改性NaY分子筛的吸附脱氮性能

对Cr~(3+)离子改性NaY分子筛的实验条件进行了研究,通过XRD、FT-IR、N_2吸附-脱附等方法对改性后的CrY分子筛进行表征,确定最佳改性条件为温度40℃,Cr~(3+)浓度0.5 mol/L,改性两次。FT-IR谱图表明,CrY分子筛波数1 147 cm~(-1)处峰明显消失,且波数1 024 cm~(-1)峰与标准的NaY分子筛相比发生了蓝移现象,可以判定Cr~(3+)交换到分子筛骨架上。考察了吸附时间和温度对CrY分子筛吸附脱除模拟燃料中喹啉的影响。结果表明,吸附温度对吸附影响不大,可在室温下进行。CrY对喹啉的吸附主要为化学吸附,且吸附类型为配位吸附和π络合吸附,最佳吸附时间为30 min,吸附等温线线性回归表明,CrY分子筛对喹啉吸附动力学模型为L型和F型混合吸附。     

Reaction of benzoyl and trichloroacetyl isocyanates with quinoline

Conclusions Trichoroacetyl isocyanate under the influence of quinoline forms ditrichloroacetylcarbodiimide, which adds to the C=N bond of quinoline on the type of a 2+4-cycloaddition. Benzoyl isocyanate under the influence of quinoline forms the dimer.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.2, pp.456–458, February, 1973.     

Synthesis and Crystal Structure of 8-（2,3-Dimethoxyphenyl）-10,11,12,13- tetrahydro-9H-benzo If] cyclohepta [c] quinolie

The title compound 8-（2,3-dimethoxyphenyl）-10,11,12,13-tetrahydro-9H-benzo[f]- cyclohepta[c]quinoline （C26H25NO2, Mr = 383.47） was synthesized and characterized by IR, 1H NMR, 13C NMR and elemental analysis. The crystal belongs to triclinic, space group PI with a = 8.1490（16）, b = 9.2550（19）, c = 14.373（3） A, α = 86.96（3）,β= 89.66（3）, γ= 70.32（3）°, Z = 2, V= 1019.2（4） A3, Dc = 1.250 g.cm^-3,μ（MoKα） = 0.078 mm^-1, F（000） = 408, the final R = 0.0555 and wR = 0.1240 for 2228 observed reflections （I 〉 2σ（I））. X-ray analysis reveals that the seven-numbered ring is slightly similar to a six-numbered ring, forming the chairlike conformation. The four rings （Ⅰ, Ⅱ, Ⅲ and Ⅳ） in the benzo[f]cyclohepta[c]quinoline moiety form a screw structure.     

Study on fluorimetric properties of 1,2-dihydro-2,2,4-trimethylquinoline

The title compound, 1,2-dihydro-2,2,4-trimethylquinoline (TMQ), is a quinoline family member and is among others used to prevent the oxidative degradation of polymers. TMQ has been characterized by its fluorescence emission. In this work the effects of solvent, acidity, continuous irradiation and the influence of some interferents upon the fluorescence intensity of TMQ were investigated. Under the selected conditions (in propan-1-ol solution at λ_excitation/λ_emission = 334 nm/412 nm), the fluorescence intensity is proportional to the concentration of TMQ over the range 0.05–5 μg ml^?1 with a correlation coefficient of 0.9963. The proposed method was applied to the determination of TMQ in synthetic mixtures of polymer additives and specific rubber samples.     

Reaching for two new stable ambiphilic quinoline‐derived N‐heterocyclic carbenes at DFT level

A detailed investigation on the thermodynamic and kinetic stability of four carbenic tautomers of quinoline 1 , including quinoline‐2‐ylidene 2 , quinoline‐3‐ylidene 3 , quinoline‐4‐ylidene 4 , and 3,4‐dihydroquinoline‐4‐ylidene 5 , reveals that singlet planar six‐membered ring N‐heterocyclic carbenes (NHCs) 2 and 4 have less stability than Arduengo type NHC but seems to have enough conceivably for reaching at B3LYP/aug‐cc‐pVTZ//B3LYP/6–31+G* and B3LYP/6–311++G**//B3LYP/6–31+G* levels. All these six‐membered NHCs are extremely ambiphilic with the more nucleophilic and electrophilic characters compared to the Arduengo type one. The aromaticity of singlet 2 and 4 is a significant contributor to their stability which is confirmed through their Nucleus‐independent chemical shift(1)_zz values. Finally, among 2–5 , the normal NHC 2 is thermodynamically preferred but the remote NHC 4 is kinetically proffered over the other isomeric carbenes. The effects of different N‐ or C‐substituted NHCs of 2 are studied using appropriate isodesmic reactions. The trimethylsilyl substituent exhibits slightly larger carbene stabilization in quinoline‐derived NHCs than the pyridine analogue. © 2014 Wiley Periodicals, Inc.     

A new fluorescent probe for zinc(II): an 8-hydroxy-5-N,N-dimethylaminosulfonylquinoline-pendant 1,4,7,10-tetraazacyclododecane

A new fluorescent probe for Zn2+, namely, 8-hydroxy-5-N,N-dimethylaminosulfonylquinolin-2-ylmethyl-pendant cyclen (L8), was designed and synthesized (cyclen=1,4,7,10-tetraazacyclododecane). By potentiometric pH, 1H NMR, and UV spectroscopic titrations, the deprotonation constants pKa1-pKa6 of L(8)4 HCl were determined to be <2, <2, <2 (for amino groups of the cyclen and quinoline moieties), 7.19+/-0.05 (for 8-OH of the quinoline moiety), 10.10+/-0.05, and 11.49+/-0.05, respectively, at 25 degrees C with I=0.1 (NaNO3). The results of 1H NMR, potentiometric pH, and UV titrations, as well as single-crystal X-ray diffraction analysis, showed that L8 and Zn2+ form a 1:1 complex [Zn(H-1L8)], in which the 8-OH group of the quinoline ring of L8 is deprotonated and coordinates to Zn2+, in aqueous solution at neutral pH. On addition of one equivalent of Zn2+ and Cd2+, the fluorescence emission of L8 (5 microM) at 512 nm in aqueous solution at pH 7.4 [10 mM HEPES with I=0.1 (NaNO3)] and 25 degrees C increased by factors of 17 and 43, respectively. We found that the cyclen moiety has the unique property of quenching the fluorescence emission of the quinolinol moiety when not complexed with metal cations, but enhancing emission when complexed with Zn2+ or Cd2+. In addition, the Zn2+-L8 complex [Zn(H-1L8)] is much more thermodynamically and kinetically stable (Kd{Zn(H-1L8)}=[Zn2+]free[L8]free/[Zn(H-1L8)]=8 fM at pH 7.4) than the Zn2+ complexes of our previous Zn2+ fluorophores ([Zn(H-1L2)] and [Zn(L3)]). Furthermore, formation of [Zn(H-1L8)] is much faster than those of [Zn(H-1L2)] and [Zn(L3)]. The staining of early-stage apoptotic cells with L8 is also described.     

Increase the Degradation Efficiency of Organic Pollutants with a Radical Scavenger （Cl^-） in a Novel Photoelectrocatalytic Reactor

Photoelectrocatalytic degradation performance of quinoline in saline water was investigated using a new-designed continuous flow three-dimensional electrode-packed bed photocatalytic reactor.It is interesting to find that chloride ion has an obvious enhancement effect rather than a scavenging effect on the photoelectrocatalytic degradation of quinoline,and create a kinetic synergetic effect in the photoelectrocatalytic reactor.     

2'-硼酸基苯甲醛-7-(8-羟基-5-磺酸基)喹啉腙衍生物的合成及对Pb2+的识别

合成了2', 3'和4'-硼酸基苯甲醛-7-(8-羟基-5-磺酸基)喹啉腙衍生物(化合物1~3), 研究了硼酸基团取代位置对主体分子识别金属离子客体性能的影响, 比较了不同主体分子与Pb2+结合能力的差异. 研究结果表明, 在pH=7.0的KH2PO4-NaOH缓冲溶液中, 3种腙衍生物对Pb2+均具有选择性识别作用, 主客体分子间形成1∶1型的发光配合物. 其中邻位取代的化合物1与Pb2+的结合能力比化合物2和3强, 配合物1-Pb2+的最大发射波长为477 nm, 稳定常数为1.1×103 L/mol. 其它金属离子如Cu2+, Mn2+, Mg2+, Fe2+, Ca2+, Co2+, Ni2+, Hg2+, Cd2+和Ag+ 等对主体分子荧光光谱的影响较小. 同时, 荧光强度的变化值与Pb2+浓度在0.36~10 μmol/L范围内呈现良好的线性关系, 相关系数R=0.9976(n=16), 检出限为0.23 μmol/L. 将此方法用于环境水样中Pb2+的测定, 回收率为92%~108%.     

Bacterial Degradation of Quinoline and Derivatives—Pathways and Their Biocatalysts

A series of interesting enzymes were discovered during investigations on the degradation of quinoline by microorganisms. These include the molybdenum-containing hydroxylases that catalyze the transformation 1 → 2 and the unusual 2,4-dioxygenases that catalyze the reaction 3 → 4 . The application of the hydroxylases may even be interesting in industry, because several quinoline derivatives are used as pharmaceuticals or agrochemicals.