X射线光电子能谱法研究UV_(254nm)光催化、O_3强化UV_(254nm)光催化和真空紫外光催化降解甲醛中Pt-TiO_2薄膜的表面性质(英文)

以Pt-TiO2为光催化剂,研究了气相甲醛分别在35 h连续UV254 nm光催化、O3强化UV254 nm(O3+UV254 nm)光催化和真空紫外(UV254+185 nm)光催化中的降解效率,考察了副产物O3的去除率,采用X射线光电子能谱(XPS)法分析Pt-TiO2在不同光催化前后Pt的电子态和累积有机产物,研究纳米Pt对甲醛降解和O3去除的强化机理.连续光催化降解实验表明,以纳米Pt改性TiO2可以同时增强甲醛和O3的去除率,特别是O3的去除率可提高3.1–3.4倍.对催化剂C 1s和O 1s峰分别经分峰拟合处理后,发现Pt-TiO2上累积的含羰基和羟基的有机物含量按以下顺序减少:UV254 nm光催化O3强化UV254 nm光催化真空紫外光催化,而在连续35 h光催化降解过程中,催化剂的失活现象却按相反的方向变得越来越不明显.负载的金属Pt在O3+UV254 nm和UV254+185nm光催化过程中被氧化成PtOads和Pt4+物种,而在UV254 nm光催化过程中金属Pt未被氧化,所以推测是气相中的O3和羟基自由基参与金属Pt的氧化过程.Pt-TiO2表面高价态的Pt氧化物种可作为光生电子捕获中心,强化光生载流子的分离过程,增强Pt-TiO2的光催化活性.Pt氧化物种可作为O3分解的活化中心,使Pt-TiO2对O3的分解效率远高于纯TiO2.以XPS对比研究在三种不同光催化环境中Pt-TiO2表面性质,可以解释在UV254+185 nm光催化过程中纳米Pt对甲醛和O3同时去除的强化机理,并说明了催化剂不失活的内在原因.     

TiO2薄膜光催化臭氧化邻苯二酚

 研究了用碳黑改性的TiO2薄膜催化剂光催化氧化邻苯二酚的反应．结果表明，臭氧投加量对邻苯二酚的降解和总有机碳（TOC）的去除有重要影响，与光催化氧化（TiO2／UV／O2）、单独臭氧化（O3）和光助臭氧化（UV／O3）过程相比，邻苯二酚光催化臭氧化（TiO2／UV／O3）过程能明显增大TOC的去除率．动力学研究表明，邻苯二酚完全氧化过程遵循零级反应，TOC的降解仅取决于臭氧或氧气的浓度而与邻苯二酚的浓度无关；邻苯二酚在TiO2／UV／O3作用下完全氧化的速率常数是UV／O3作用下的1．32～1．80倍（在相同的臭氧浓度下），是TiO2／UV／O2作用下最大速率常数的2．56～5．36倍，是UV／O2作用下最大速\r\n率常数的5．47～11．4倍．     

Ru0.7Si0.3O2/Ti电极电催化氧化处理硝基苯废水

制备了Ru0.7Si0.3O2/Ti电极,并以该电极作为氧化阳极,不锈钢为阴极,电催化氧化降解废水中硝基苯。 实验结果表明,当硝基苯初始质量浓度为220 mg/L时,最佳条件为：电流密度25×10-3 A/cm2;Na2SO4作为电解质时加入量为8 g/L;溶液初始pH=2。 在此最佳条件下,硝基苯去除率大于85%,TOC去除率大于50%,表明Ru0.7Si0.3O2/Ti阳极能有效去除废水中有机污染物;对中间产物的检测结果表明,硝基苯的降解是阴阳两极协同作用的结果。     

Pr2O3/TiO2纳米粒子的制备及其US/UV协同催化降解苯酚的研究

以钛酸丁酯为原料,用溶胶-凝胶(Sol-gel)法制备了Pr2O3/TiO2纳米粒子.采用X光衍射仪对粉体的物相进行了表征.样品经500 ℃焙烧2 h后,0.5%(摩尔分数)Pr3 TiO2纳米粉末为单一的锐钛型结构.研究了US(超声波)/UV(紫外光)协同催化氧化水中苯酚的降解效果,考察了超声波声强、溶液pH值、反应温度和催化剂投加量对苯酚降解速率的影响.研究结果表明:US/UV协同催化氧化要比单独超声波或光化学处理效果显著,证实了声光联合技术具有明显的协同效应.     

铜和铝离子/UV催化臭氧降解偶氮二异丁腈废水研究

利用多相催化臭氧(O3)工艺处理偶氮二异丁腈(AIBN)废水,探讨不同催化O3体系(Cu2+、Al3+、Cu2++Al3+/UV催化O3)对AIBN废水中氰类污染物的降解特性,并对不同催化O3体系的动力学特性进行研究。结果表明,金属离子对催化O3工艺的处理效率具有明显影响,不同催化O3工艺对CN-去除作用都呈现起始去除速率较高而后减弱的特点,其中Cu2+和Al3+共同催化O3工艺的整体去除率较高,优于单独Cu2+和Al3+的催化性能。这可能是由于p H变化、金属离子与CN-配合作用、金属离子和O3作用的综合影响结果。动力学研究结果表明,不同催化O3体系降解AIBN废水中的CN-污染物的氧化反应符合准一级动力学反应,表观反应速率常数k在0.0245~0.00301 min-1之间。     

Fe(II)(EDTA)螯合物/UV催化臭氧工艺降解PAM溶液研究

研究采用Fe(II)(EDTA)螯合物/UV催化臭氧降解聚丙烯酰胺(PAM)溶液。考察Fe(II)(EDTA)螯合物/UV催化臭氧法对PAM溶液粘度、PAM去除率和可生化性的影响。研究表面活性剂对Fe(II)(EDTA)螯合物/UV催化臭氧工艺降低PAM粘度的影响,并探讨草酸对该工艺降解PAM溶液影响规律。研究结果表明,Fe(II)(EDTA)螯合物/UV催化臭氧法对PAM溶液降解效能良好,在15min内,PAM溶液粘度的可以降低57%,在120min后,PAM去除率可达75%,B/C从0.121提升到0.423。表面活性剂对Fe(II)(EDTA)螯合物/UV催化臭氧工艺降低PAM溶液粘度影响较小。草酸不利于Fe(II)(EDTA)/UV催化臭氧工艺去除PAM和降低PAM溶液粘度,这是因为草酸造成的酸性环境抑制了臭氧在水中的分解作用,从而导致草酸/Fe(II)(EDTA)/O3体系中PAM溶液的降粘效果和去除率低于Fe(II)(EDTA)/O3体系。     

SnO_2/TiO_2纳米管复合光催化剂的性能及失活再生

基于微波水热法和微乳液法合成SnO2/TiO2纳米管复合光催化剂.通过X射线衍射(XRD)、配有能量色散X射线光谱仪(EDX)的透射电镜(TEM)和电化学手段对光催化剂进行表征.以甲苯为模型污染物,考察光催化剂在紫外光(UV)和真空远紫外光(VUV)下的性能及失活再生.结果表明,SnO2/TiO2纳米管复合光催化剂形成三元异质结(锐钛矿相TiO2(A-TiO2)/金红石相TiO2(R-TiO2)、A-TiO2/SnO2和R-TiO2/SnO2异质结),促使光生电子-空穴对的有效分离,提高光催化活性.SnO2/TiO2表现出最佳的光催化性能,UV和VUV条件下的甲苯降解率均达100%,CO2生成速率(k2)均为P25的3倍左右.但由于UV光照矿化能力不足,中间产物易在催化剂表面累积.随着UV光照时间的增加,SnO2/TiO2逐渐失活,20 h后k2由138.5 mg·m-3·h-1下降到76.1 mg·m-3·h-1.利用VUV再生失活的SnO2/TiO2,过程中产生的·OH、O2-·、O(1D)、O(3P)、O3等活性物质可氧化吸附于催化剂活性位的难降解中间产物,使催化剂得以再生,12 h后k2恢复到143.6 mg·m-3·h-1.UV和VUV的协同效应使UV降解耦合VUV再生成为一种可持续的光催化降解污染物模式.     

碳酸氢钠溶液中微量 Mn2+离子催化氧化降解有机污染物

 考察了微量 Mn2+离子在 NaHCO3 溶液中催化 H2O2 氧化降解有机污染物的性能. 结果表明, NaHCO3, MnCl2 和 H2O2 浓度分别为 25, 0.1 和 100 mmol/L 时, 在 25 oC 下反应 180 min 后亚甲基蓝可完全脱色, 化学耗氧量和总有机碳去除率分别达到 44.0% 和 13.8%. 该催化体系对甲基橙、罗丹明 B 以及垃圾渗滤液等都有较好去除效果. 紫外-可见光谱分析及反应动力学测试表明, MnIV=O 是该催化体系主要活性物种.     

微波诱导Fe2O3/Al2O3催化剂催化氧化处理水中苯酚

 以γ-Al2O3为载体,采用浸渍-焙烧法制备了Fe2O3/Al2O3催化剂,并将其应用于微波诱导催化氧化处理模拟含酚废水. X射线衍射和X射线荧光光谱测试结果表明,活性组分氧化铁在催化剂中以α-Fe2O3的形式存在,其含量为3.71%. 与载体氧化铝相比,Fe2O3/Al2O3催化剂的比表面积和平均孔径及平均孔容略有降低. 对于100 mg/L的模拟含酚废水,最佳的处理工艺条件为: 微波辐照功率400 W,辐照时间5 min,催化剂加入量60 g/L,H2O2浓度600 mg/L,体系pH＞4. 在此工艺条件下,水中苯酚的去除率达97.98%. 催化剂连续使用20次后苯酚去除率仍达96.34%. 表观反应动力学研究表明,在氧化铁催化剂存在的条件下,微波诱导H2O2产生氧化性极强的羟基自由基,整个反应过程可分为微波诱导阶段和催化氧化阶段,两个阶段的氧化过程均符合一级反应动力学规律.     

金属氧化物(Fe2O3, CuO,NiO)改性对TiO2纳米管阵列光电催化活性的增强效应

采用阳极氧化法和阴极电沉积法制备了Fe2O3,CuO和NiO纳米粒子改性的高度有序的TiO2纳米管(TiO2-NT)阵列.运用场发射扫描电子显微镜(FE-SEM),透射电子显微镜(TEM),X射线衍射(XRD)和紫外-可见漫反射光谱等手段对Fe2O3/TiO2-NT、CuO/TiO2-NT和NiO/TiO2-NT复合电极进行表征.以苯酚为模拟污染物,考察复合电极的光电性能.结果表明,金属氧化物(Fe2O3,CuO,NiO)纳米粒子成功沉积在TiO2-NTs的管口、内壁和管底.金属氧化物改性复合电极的光电催化活性比未改性的TiO2-NTs提高了2倍以上.Fe2O3/TiO2-NTs在可见光区显示出最高的吸收强度.以Fe2O3/TiO2-NTs为阳极处理苯酚废水,光照120min后苯酚去除率达到96%,而未改性的TiO2-NTs的苯酚去除率只有41%.此外,Fe2O3/TiO2-NTs在生成低毒中间产物方面表现出良好的性能.较高的复合电极光电催化活性主要是由于TiO2纳米管和过渡金属氧化物纳米粒子间构筑的高界面面积异质纳米结构,有效地促进了电子转移,抑制了光生电子-空穴对的复合.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

探究“铁的锈蚀条件”实验创新设计

设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。