钙钛矿型LaxSr1－xNi1－yCoyO3光电催化活性研究

用甘氨酸-硝酸盐燃烧合成法, 制备La_xSr_1－xNi_1－yCo_yO₃复合氧化物的陶瓷粉末, 对钙钛矿氧化物进行了XRD结构分析. 在通氧或不通氧下测试氧还原和氧析出的循环伏安曲线. 结果表明: 该氧电极具有双功能催化特性, 但不完全可逆. 利用汞灯作为激发光源, 进行几种水溶性染料和五种混合染料光解实验, 利用紫外-可见、红外以及人工神经网络光度法研究La_xSr_1－xNi_1－yCo_yO₃的催化性能. 结果表明: La_xSr_1－xNi_1－yCo_yO₃ (x＝0.7, 0.9, 1; y＝0.3, 0.75)复合氧化物都具有较强光催化特性; La_xSr_1－xNi_1－yCo_yO₃的光催化活性高于La_xSr_1－xNiO₃, 这与B位离子(Ni^2—, Co^2－)的电子构型有关; Co^2＋的加入可使La_xSr_1－xNiO₃的光催化活性有所提高.     

空气中合成固溶体荧光粉Ba2(Zn, Mg)Si2O7:Ce3+,Eu2+,Eu3+及其发光特性

采用高温固相法在空气中合成了Ba_1.97-yZn_1-xMg_xSi₂O₇:0.03Eu,yCe³⁺系列荧光粉。分别采用X-射线衍射和荧光光谱对所合成荧光粉的物相和发光性质进行了表征。在紫外光330~360 nm激发下,固溶体荧光粉Ba_1.97-yZn_1-xMg_xSi₂O₇:0.03Eu的发射光谱在350~725 nm范围内呈现多谱峰发射,360和500 nm处有强的宽带发射属于Eu²⁺离子的4f⁶5d¹-4f⁷跃迁,590~725 nm红光区窄带谱源于Eu³⁺的⁵D₀-⁷F_J (J=1,2,3,4)跃迁,这表明,在空气气氛中,部分Eu³⁺在Ba_1.97-yZn_1-xMg_xSi₂O₇基质中被还原成了Eu²⁺;当x=0.1时,荧光粉Ba_1.97Zn_0.9Mg_0.1Si₂O₇:0.03Eu的绿色发光最强,表明Eu³⁺被还原成Eu²⁺离子的程度最大。当共掺入Ce³⁺离子后,形成Ba_1.97-yZn_0.9Mg_0.1Si₂O₇:0.03Eu,yCe³⁺荧光粉体系,其发光随着Ce³⁺离子浓度的增大由蓝绿区经白光区到达橙红区;发现名义组成为Ba_1.96Zn_0.9Mg_0.1Si₂O₇:0.01Ce³⁺,0.03Eu的荧光粉的色坐标为(0.323,0.311),接近理想白光,是一种有潜在应用价值的白光荧光粉。讨论了稀土离子在Ba₂Zn_0.9Mg_0.1Si₂O₇基质中的能量传递与发光机理。     

CeCl3-CdCl2-H2O和CeCl3-CdCl2-HCl-H2O的相平衡

测定了三元系CeCl₃-CdCl₂-H₂O (25 ℃)和四元系CeCl₃-CdCl₂-HCl(～8.4％)-H₂O(25 ℃) 的相平衡溶度数据,绘制了相应的溶度图.该三元系是由5个固相区CdCl₂&;#8226;2.5H₂O(原始盐)、CdCl₂&;#8226;H₂O(原始盐)、6CdCl₂&;#8226;CeCl₃&;#8226;14H₂O、4CdCl₂&;#8226;CeCl₃&;#8226;12H₂O、CeCl₃&;#8226;7H₂O(原始盐)组成的复杂体系.该四元系是由5个固相区CdCl₂&;#8226;H₂O(原始盐)、9CdCl₂&;#8226;CeCl₃&;#8226;19H₂O、6CdCl₂&;#8226;CeCl₃&;#8226;14H₂O、4CdCl₂&;#8226;CeCl₃&;#8226;12H₂O、CeCl₃&;#8226;7H₂O(原始盐)组成的复杂体系.其中6CdCl₂&;#8226;CeCl₃&;#8226;14H₂O在该三元系是介稳化合物.9CdCl₂&;#8226;CeCl₃&;#8226;19H₂O 、6CdCl₂&;#8226;CeCl₃&;#8226;14H₂O和4CdCl₂&;#8226;CeCl₃&;#8226;12H₂O用X射线粉末衍射及TG-DTG和DSC等方法进行了研究,并对X射线粉末衍射进行了指标化.     

纳米钙钛矿LaxSr1-xFe1-yCoyO3复合氧化物的制备和表征

用甘氨酸-硝酸盐燃烧合成法，制备La_xSr_1-xFe_1-yCo_yO₃复合氧化物的陶瓷粉末，对该钙钛矿型氧化物进行了XRD、IR、紫外漫反射光谱及循环伏安曲线分析。结果表明：该复合氧化物粉体平均晶粒为15.3～29.8 nm,为立方和正交晶系。该氧电极具有双功能催化特性，但不完全可逆。对水溶液染料进行光解实验，利用紫外-可见、人工神经网络光度法研究La_xSr_1-xFe_1-yCo_yO₃的催化性能。结果表明：CO²⁺的加入可使La_xSr_1-xFeO₃的光催化活性有所提高，B位离子(Fe³⁺，CO²⁺)改变与加入，使La_xSr_1-xFe_1-yCo_yO₃(x=0.7，0.3；y=0.3，0.9，1)光催化活性高于La_xSr_1-xFeO₃。同时，对5种染料进行紫外光解，在0.75 h，脱色率大于91%，并为动力学一级反应。     

层状O2结构锂锰氧化物Li0.60[MgxCoyMn1-x-y]O2的制备及结构表征

本文采用离子交换法分别制备了双复合锂锰氧化物Li_0.60[Mg_xMn_1-x]O₂(0.05 ≤ x ≤ 0.15)和三复合锂锰氧化物Li_0.60[Mg_xCo_yMn_1-x-y]O₂(x=0.05，0.05 ≤      

La-Ce对PbTiO3陶瓷气相扩渗生成La2Ti6O15CeTi21O38的陶瓷材料及其电性能

报道了采用气相法对PbTiO₃陶瓷扩渗La-Ce混合稀土元素的研究. 在气相扩渗过程中, La, Ce与PbTiO₃陶瓷组元发生了复杂反应,生成了稀土化合物La₂Ti₆O₁₅和CeTi₂₁O₃₈, 制备出未见报道的La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃陶瓷材料, 经测试其导电性能发生了十分显著的变化. La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃陶瓷材料的室温电阻率从2.0 ×10¹⁰ W·m下降为0.248 W·m,而且随着温度的变化, 晶粒电阻呈现明显的PTCR效应,而晶界电阻随着温度的升高,呈急剧连续降低状态,总电阻的变化规律与晶界电阻的变化相一致, 试样总电阻的PTCR效应已不存在, 近趋导体. 经XPS测试分析, 进一步证实了La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃陶瓷材料中铅、钛等元素均有变价, 因而导致了La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃陶瓷材料电阻率的降低, 测试结果还首次给出了La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃陶瓷材料中各元素结合能位置的峰值. TG-DTA热分析表明La₂Ti₆O₁₅-CeTi₂₁O₃₈-PbTiO₃陶瓷材料具有较好的高温热稳定性.     

o-ZrW1.6Mo0.4O8·H2O正交相的合成与表征

The precursor ZrW_1.6Mo_0.4O₇(OH)₂(H₂O)₂ was characterized by IR and XRD methods. δ′-ZrW_1.6Mo_0.4O₈ was prepared by careful controlling the annealing conditions from the precursor and was determined to have the formula as o-ZrW_1.6Mo_0.4O₈·H₂O by TG-DSC, IR, and XRD methods. The relation between o-ZrW_1.6Mo_0.4O₈·H₂O and o-ZrW_1.6Mo_0.4O₈ was discussed through variable temperature XRD patterns. Further more, the mechanism of the precursor dehydration was suggested.     

298.15 K Li2B4O7-MgCl2-H2O体系热力学性质的电动势法测定及离子相互作用模型的研究

测定了298.15 K下, 无液接电池Li-ISE│Li₂B₄O₇ (m_A)(aq.), MgCl₂(m_B)(aq.)│AgCl/Ag的电动势, 利用测定结果计算了Li₂B₄O₇-MgCl₂-H₂O体系离子强度在0.05～3 mol•kg^－1范围内, 不同MgCl₂离子强度分数的溶液中LiCl的平均活度系数, 并给出了其随离子强度I, B₄O₇^2－和Mg^2＋浓度的变化规律. 结合以往关于该体系和Li₂B₄O₇-LiCl-H₂O, Li₂B₄O₇-H₂O体系的等压研究结果, 用迭代和多元线性回归方法对Li^＋-Mg^2＋-Cl^－-B₄O₇^2－-H₂O体系的离子相互作用模型进行了研究. 具体方法为考虑了该体系在不同的总硼浓度范围H₃BO₃, B(OH)₄^－, B₃O₃(OH)₄^－和B₄O₅(OH)₄^2－四种含硼化合物的存在以及各硼化合物间的化学平衡, 以修正了的Pitzer渗透系数方程和活度系数方程为基础, 对该体系的等压法和电动势法研究结果进行最小二乘拟合, 拟合的标准偏差为0.0167, 用该模型计算的该体系的渗透系数、活度系数与实验值基本一致.     

Bi2WO6量子点(QDs)修饰Bi2MoO6-xF2x异质结的构筑及其催化活性增强机理

采用简单沉积-沉淀法合成了Bi₂WO₆@Bi₂MoO_6-xF_2x（BWO/BMO6-xF2x）异质结,借助XRD、XPS、TEM、SEM、EDS、UV-Vis-DRS、PC和EIS等测试技术对其组成、形貌、光吸收特性和光电化学性能等进行系统表征,并以模型污染物罗丹明B（RhB）的光催化降解作为探针反应来评价Bi₂WO₆@Bi₂MoO_6-xF_2x异质结的光催化活性增强机制。形貌分析表明,所得Bi₂MoO₆微球由大量厚度为20~50 nm的纳米片组成;FE-SEM和HR-TEM分析表明,尺寸约为10 nm的Bi₂WO₆量子点均匀沉积在Bi₂MoO_6-xF_2x微球表面,形成新颖的Bi₂WO₆@Bi₂MoO_6-xF_2x异质结;与纯Bi₂MoO₆或者Bi₂WO₆相比,1∶1Bi₂WO₆@Bi₂MoO_6-xF_2x异质结表现出更好的光催化活性和光电流性质,其对RhB光催化降解的表观速率常数分别为纯BMO和BWO的6.4和11.6倍。PC和EIS图谱分析表明,Bi₂WO₆量子点表面沉积显著提高Bi₂MoO_6-xF_2x光生电子/空穴的分离效率和迁移速率;活性物种捕获实验证明了·O₂^-和h⁺是主要的活性物种。根据实验结果,探讨了F^-掺杂和Bi₂WO₆量子点之间的协同效应对Bi₂MoO₆的光催化活性的影响机制。     

由大环配体[As4W40O140]28-与NiII形成的新型超大杂多化合物

在pH = 4.0的水溶液中, NiCl₂·6H₂O, NH₄Cl与Na₂₇[NaAs₄W₄₀O₁₄₀]·60H₂O反应, 得到了新的杂多砷钨酸盐(NH₄)₂₀[Na₂(H₂O)₂Ni(H₂O)₅{Ni(H₂O)}₂As₄W₄₀O₁₄₀]·61H₂O单晶, 用X射线单晶衍射法及元素分析确定了其结构, 晶体属三斜晶系, P¹空间群; 其晶胞参数为: a = 1.33135(18), b = 1.9722(3), c = 3.6430(5) nm, α = 78.010(2)°, β = 82.145(2)°, γ = 74.385(2)°, V = 8.978(2) nm3, Z = 2, R1 = 0.0512, wR2 = 0.0684 (I > 2σ). 在聚阴离子[Na₂(H₂O)₂Ni(H₂O)₅{Ni(H₂O)}₂As₄W₄₀O₁₄₀]^20-中, 2个Ni²⁺和2个Na⁺分占大环配体[As₄W₄₀O₁₄₀]^28-内的4个S2空位, 每个S2位提供4个O_d向金属离子配位, 2个Ni²⁺的配位数为6, 两个Na⁺的配位数分别为5和6, 另一个Ni²⁺处于环外, 与[As₄W₄₀O₁₄₀]^28-的一个端基氧(O_d)桥连成键, 其配位数为6.     

基于离子交换树脂制备多孔氧化铝球及在非水体系中分离银杏内酯

以磺酸型大孔离子交换树脂D072为模板, 设计合成了球形的多孔氧化铝, 利用XRD、SEM和氮气吸附仪对其结构进行了表征. 以这种球形多孔氧化铝作为分离材料, 考察了其在非水体系中对银杏黄酮和银杏内酯的吸附选择性, 在最佳分离条件下, 制备了纯度为58.5%, 且不含任何黄酮的银杏内酯. 利用红外光谱法证明了吸附机理为配位吸附.     

PYR树脂对甜菊糖的吸附与洗脱性能研究

系统研究了PYR型树脂对甜菊糖的吸附与洗脱性能，并与目前国内应用于甜菊糖提取分离的某些商品化吸附树脂进行了比较。结果表明，PYR树脂比其它树脂具有更优的性能，其静态吸附容量比AB—8树脂提高25％，且吸附速度快，易于洗脱再生，是一种具有工业化应用前景的新型吸附剂。     

大孔吸附树脂对银杏叶黄酮类化合物吸附及解吸的研究

本文介绍了DM－130，LSA－10和LSA－20型三种大孔吸附树脂对银杏叶黄酮类化合物的吸附性能，考察了pH值，温度，浸出液浓度等影响吸附性能的因素，结果表明DM－130型树脂对黄酮类化合物具有较好的吸附效果。     

Physico-chemical applications of liquid chromatography I. Investigation of the adsorption of cardiac glycosides from water-ethanol solutions on silanized silica

Summary Using the cardiac glycoside cymarin as the example the application of liquid chromatography for the study of adsorption from solutions and the determination of the corresponding thermodynamic characteristics was investigated. The adsorption isotherm of cymarin at small concentrations from a water-ethanol solvent on silica gel modified by dimethyldichlorosilane was measured under static conditions using analytical LC to determine the concentrations of solutions after adsorption. The values of the Henry constants were obtained by extrapolating the slope of the adsorption isotherm down to zero concentration. The specific retention volumes for different but small sample sizes of cymarin in the chromatographic column were measured, the adsorbent and the water-ethanol eluent being the same as in the static conditions. The specific retention volume for a small (zero) sample size determined by liquid chromatography experiment coincides with the Henry constant of cymarin adsorption determined in static conditions. In favourable cases liquid chromatography can be used to determine the equilibrium constants for adsorption from solution. The dependence of the Henry constants on temperature was investigated for several cardiac glycosides. The influence of the modification of the adsorbent surface on the separation of the cardiac glycosides was also studied.     

PURIFICATION OF GINKGO LEAVES EXTRACT WITH MACROPOROUS ADSORBENT BASED ON UREA-FORMALDEHYDE CONDENSED POLYMERS

I INTRODUCTIONGinkgo biloba L. is one of the important economic trees, which is widely distributed inChina. In recent years, medicinal and healthful preparations based on the extractS from ginkgoleaves have been rapidly developed for the treatment of peripheral circulatory and cerebralinsufficiencyl']. Such eXtracts contain flavonol glycosides and terpene lactones as thepharmacologically active compounds. Organic-solvent extraction is one of the earliest methodsto prepare the extracts o…     

THE SYNTHESIS AND CHARACTERIZATION OFSOME POROUS RESINS AND THEIR ADSORPTIONPROPERTY ON STEVIA GLYCOSIDES

1.INTRODUCTIONFromtheleavesofSteviaRebaudianaBertoni,asweetherbindigenoustoelevatedterrainonthebordersofBrazilandParaguay,eightsteviaglycosideshasbeenisolatedinayieldof10~15%andutilizedasahigh-sweetness,low-calorie,nonnutritionsweetener[1-3].Stevioside,rebaudiosideAandrebaudiosideCarepresentinthelargestquantitiesoftheeightsteviaglycosides.Amongthesethreeglycosides,rebaudiosideAisknownasthebestsweetenerwithrespecttotheintensityofsweetnessaswellasthequalityoftaSte,whiletheothertwomajorsw…     

Selectivity of polymer adsorbent in adsorptive separations of stevia diterpene glycosides

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Preparation of 4‐butylaniline‐bonded silica gel for the solid‐phase extraction of flavone glycosides

To extract flavone glycosides efficiently, a new extraction material based on 4‐butylaniline‐bonded silica gel was prepared using a two‐step grafting method including a ring‐opening reaction and synchronous hydrolysis. Preparation of the silica‐based material was easily achieved under mild conditions, and the material was characterized by Fourier transform infrared spectroscopy, elemental analysis, and scanning electron microscopy. The material was used in solid‐phase extraction, and the extraction can be performed in neutral conditions without regard to ionic strength. Selectivity tests of 14 compounds on the extraction cartridge showed that the material has a high affinity to flavone glycosides in contrast to octadecyl silica, and the extraction yields for four flavone glycosides were found to be >93%. Selectivity tests further reveal that the adsorption on its surface is likely attributed to multiple interactions, including hydrophobic interactions, π–π interactions, and hydrogen bonding. To explore the applicability of 4‐butylaniline‐bonded silica gel, naringin and hesperidin from Simotang oral liquid were extracted, and the extraction yields were >90%, which is distinguished from <28% on octadecyl silica cartridge.     

THE SYNTHESIS AND CHARACTERIZATION OF SOME POROUS RESINS AND THEIR ADSORPTION PROPERTY ON STEVIA GLYCOSIDES

A series of porous resins (PYR) with different content of pyridyl group were prepared,and their physical structure and adsorption properties on the stevia glycosides were studied in detail.After the selective adsorption of PYR resins,the rebaudioside A could be separated from the other components of the stevia glycosides,and a new method for obtaining pure rebaudioside A is reported.     

PURIFICATION OF GINKGO LEAVES EXTRACT WITH MACROPOROUS ADSORBENT BASED ON UREA—FORMALDEHYDE CONDENSED POLYMERS

The relationship between the adsorption properties for the active components of ginkgo leaves and the structure of the adsorbents based on urea-formaldehyde condensed polymers was investigated.The results revealed that these adsorbents showed very high adsorpton selectivity for both flavonol glycosides and terpene lactones contained in ginkgo leaves.Thus,an adsorption separation procedure for purification of ginkgo leaves extracts was developed.