W／O微乳液制备纳米粒子的研究

介绍了微乳液的制备方法、微观结构模型和形成理论;介绍了W／O型微乳液在制备纳米粒子方面的应用,并对微乳液法制备纳米粒子的方法、原理、影响因素以及纳米粒子的表征方法进行了重点介绍。     

反相微乳液制备AgCl/PMMA复合胶乳及其抗菌性能

以聚乙二醇辛基苯基醚(OP)为表面活性剂,甲基丙烯酸甲酯(MMA)为油相构筑的反相微乳液合成纳米Ag Cl粒子,然后通过微乳液聚合制备Ag Cl/PMMA复合胶乳。利用紫外-可见吸收光谱(UV-vis)和透射电镜(TEM)研究微乳液中表面活性剂浓度(cop)、水相中盐浓度(csalt)对纳米Ag Cl粒子的形成及形貌影响,结果发现合成的Ag Cl粒子近似球状,粒径在5 nm左右;在反相微乳液中随cop、csalt的增加,形成的纳米Ag Cl粒子数增多、平均粒径有所减小。Ag Cl/PMMA复合胶乳对大肠杆菌表现出明显的抗菌活性。通过反相微乳液及其聚合技术制备包含有纳米Ag Cl的复合胶乳,方法简便、易于放大,所制备的Ag Cl/PMMA复合胶乳作为抗菌剂具有良好的应用前景。     

反相微乳液法制备纳米TiO2

以CTAB/正丁醇/正庚烷/NH.3H2O和CTAB/正丁醇/正庚烷/TiCl4反相双微乳液方式制备纳米TiO2,且采用SEM和FI-IR等分析手段对纳米TiO2的粒径、物相等方面进行分析。结果表明,在CTAB6.83g,正丁醇8.54mL,正庚烷30mL,2.4mo.lL-1的NH.3H2O6mL,0.6mo.lL-1的TiCl43mL的条件下,可以制备纳米TiO2。     

电导率法研究W/O微乳液中Pd纳米微粒的化学破乳负载

利用水-Tween-80-Span-80-环己烷微乳液合成了粒径为5~10 nm、高度分散的Pd纳米微粒. 结果表明,随着破乳剂用量的增大,含Pd微乳液与破乳剂的混合体系依次呈现微乳液、分层、胶体或微乳液体系. 破乳剂的亲水性与分子结构是影响破乳行为的主要参数. 利用混合物体系分层与再均相的临界区域,在微乳液浸渍a-Al2O3载体的同时,使其中的Pd纳米微粒破乳沉积,实现了Pd在载体表面的均匀负载. TEM及XPS分析表明,Pd的微粒粒径为10~20 nm, 以单质形态结合于载体表面.     

Isotope effect of H2/D2 and H2O/D2O for the PROX reaction of CO on the FeOx/Pt/TiO2 catalyst

The oxidation reaction of CO with O₂ on the FeOx/Pt/TiO₂ catalyst is markedly enhanced by H₂ and/or H₂O, but no such enhancement occurs on the Pt/TiO₂ catalyst. Isotope effects were studied by H₂/D₂ and H₂O/D₂O on the FeOx/Pt/TiO₂ catalyst, and almost the same magnitude of isotope effect of ca. 1.4 was observed for the enhancement of the CO conversion by H₂/D₂ as well as by H₂O/D₂O at 60 °C. This result suggests that the oxidation of CO with O₂ via such intermediates as formate or bicarbonate in the presence of H₂O, in which H₂O or D₂O acts as a molecular catalyst to promote the oxidation of CO as described below.      

Characterization of metal (Ba, Al, Si, V, and W)-incorporated TiO2 and toluene photodecomposition in the presence of H2O

This study focused on toluene photodecomposition in the presence of H₂O over metal (Ba, Al, Si, V, and W)-incorporated TiO₂. The nanometer-sized, metal-TiO₂ photocatalyst samples, including Ba²⁺, Al³⁺, Si⁴⁺, V⁵⁺, and W⁶⁺ ions, were prepared by using the solvothermal method. The X-ray photoelectron spectroscopy (XPS) results showed that the Ti-OH peak, which indicates hydrophilicity, increased with increasing Al and Si ion components but decreased with increasing Ba, V, and W ion components. The contact angles were distributed over the range of 0–10° on almost all films (200-nm thick) after irradiation for 2 h, and in particular approached 0° on the Al-TiO₂ and Si-TiO₂ nanometer-sized films after just 30 min. The toluene (100 ppm) photodecomposition in the continuous system increased in the order of Al-TiO₂>Si-TiO₂>pure TiO₂>W-TiO₂>Ba-TiO₂>V-TiO₂, and the maximum toluene conversion rate achieved was 45% over Al-TiO₂ film after 120 min. The toluene conversion remarkably increased; however, over all photocatalysts, with H₂O addition during the toluene photo-decomposed reaction, and in particular, the conversion reached up to 90% after 120 min over Al-TiO₂ and Si-TiO₂ with increased hydrophilicity. After photoreaction for 24 h, minimal carbon was deposited on the photocatalyst under both reaction conditions, with and without H₂O addition, although the deposited carbon amounts were smaller for the former. These results confirmed that the hydrophilicity of the photocatalyst had a greater effect on toluene decomposition, while the photocatalytic deactivation could be retarded by H₂O supplementation during toluene decomposition.     

A Convenient Synthesis of Some Coumarin Derivatives Using SnCl2 · 2H2O as Catalyst

Some substituted coumarins have been synthesized by von-Pechmann condensation using SnCl₂ · 2H₂O (10 mol %) as catalyst in ethanolic medium. The reactions are simple, easy in handling and environmentally benign.     

Design,Synthesis and Evaluation of Novel Molecular Hybrids between Antiglaucoma Drugs and H2S Donors

Glaucoma is a group of eye diseases consisting of optic nerve damage with corresponding loss of field vision and blindness. Hydrogen sulfide (H₂S) is a gaseous neurotransmitter implicated in various pathophysiological processes. It is involved in the pathological mechanism of glaucomatous neuropathy and exerts promising effects in the treatment of this disease. In this work, we designed and synthetized new molecular hybrids between antiglaucoma drugs and H₂S donors to combine the pharmacological effect of both moieties, providing a heightened therapy. Brinzolamide, betaxolol and brimonidine were linked to different H₂S donors. The H₂S-releasing properties of the new compounds were evaluated in a phosphate buffer solution by the amperometric approach, and evaluated in human primary corneal epithelial cells (HCEs) by spectrofluorometric measurements. Experimental data showed that compounds 1c, 1d and 3d were the hybrids with the best properties, characterized by a significant and long-lasting production of the gasotransmitter both in the aqueous solution (in the presence of L-cysteine) and in the intracellular environment. Because, to date, the donation of H₂S by antiglaucoma H₂S donor hybrids using non-immortalized corneal cells has never been reported, these results pave the way to further investigation of the potential efficacy of the newly synthesized compounds.     

胰岛素W/O型微乳液的制备及体外释药性能

制备了包封胰岛素(INS)的Tween 80-Span 80/乙醇/丁酸乙酯/水体系的W/O型微乳液。以最大增溶水量为指标,选择了合适的微乳液组分包封INS。考察了温度、盐度和pH对微乳液区域的影响。电导率法区分了微乳液的O/W、W/O和B.C.区域。动态光散射测定了微乳液的粒径和多分散度。125I同位素示踪法测定了INS微乳液体外释放效果。结果表明,微乳体系在水/乙醇(质量比为1.8∶1)的质量分数小于41%时形成W/O型微乳液,温度、盐度升高和pH降低使微乳区稍有减小。微乳液粒径和多分散度分别为35~45 nm和0.29~0.37。pH的降低对微乳液粒径影响不大,而药物的加入使微乳液粒径略有减小。载药微乳液粒径在制备3 d后突降,以后的27 d内保持在37 nm左右。该载药微乳液在7.5 h后进入缓释阶段,40 h时INS的释放率为66.20%。     

Reduction of lean NOx by ethanol over Ag/Al2O3 catalysts in the presence of H2O and SO2

The reduction of lean NOx using ethanol in simulated diesel engine exhaust was carried out over Ag/Al₂O₃ catalysts in the presence of H₂O and SO₂. The Ag/Al₂O₃ catalysts are highly active for the reduction of lean NOx by ethanol but the reaction is accompanied by side reactions to form CH₃CHO, CO along with small amounts of hydrocarbons (C₃H₆, C₂H₄, C₂H₂ and CH₄) and nitrogen compounds such as NH₃ and N₂O. The presence of H₂O enhances the NOx reduction while SO₂ suppresses the reduction. The presence of SO₂ along with H₂O suppresses the formation of acetaldehyde and NH₃. By infrared spectroscopy, it was revealed that the reactivity of NCO species formed in the course of the reaction was greatly enhanced in the presence of H₂O. The NCO species readily reacts with NO in the presence of O₂ and H₂O at room temperature, being converted to N₂ and CO₂ (CO). Addition of SO₂ suppresses the formation of NCO species and lowers the reactivity of the NCO species. However, the reduction of NOx is still kept at high conversion levels in the presence of H₂O and SO₂ over the present catalysts. About 80% of NOx in the simulated diesel engine exhaust was removed at 743 K. This revised version was published online in July 2006 with corrections to the Cover Date.     

Decolorization and Modeling of Synthetic Wastewater Using O3 and H2O2/O3 Processes

This research deals with the decolorization of synthetic wastewater, prepared with the acid 1:2 metal-complex textile dye C.I. Acid Blue 193, using the ozonation (O₃) and H₂O₂/O₃ processes. To minimize the number of experiments, they were performed using the 2^k factorial design. Five influential parameters were examined: initial dye concentration, ozone flow rate, initial pH value, decolorization time and H₂O₂ addition. The decolorization efficiency was 95% in 20 minutes (pH = 7; O₃ flow rate of 2 g/L.h) and a higher increase in the toxicity after the ozonation process (39%) indicates the formation of carcinogenic by-products. According to the variance test analysis, the initial dye concentration, the ozone flow rate, the initial pH value and the decolorization time and their first- and second-order interactions are significant, while the H₂O₂ addition was not important with respect to the discussed range. With the help of these significant factors a regression model was constructed and the adequacy of the model was checked. The obtained regression polynomial was used to model the relation between the absorbance and the influential parameters by fitting the response surface. This response surface may be used to predict the absorbance result from a set of influential parameters, or it can be rearranged in such a way as to predict the set of process decolorization parameters necessary to reduce the absorbance of wastewater with the given initial dye concentration, below the prescribed limit. It is also shown that the 2^k factorial design can be suitable for predicting the operating expenses of the ozonation.     

Effective Coke Removal in Methane to Benzene (MTB) Reaction on Mo/HZSM-5 Catalyst by H2 and H2O Co-addition to Methane

The catalytic dehydro-aromatization reaction over Mo/HZSM-5 catalyst was drastically stabilized by the co-addition of 5.4% H₂ and 1.8% H₂O to methane feed at 750 °C, 0.3 MPa and methane space velocity of 3000 mL g⁻¹ h⁻¹, suppressing the coke formation effectively, compared with single hydrogen or steam addition.     

Pressure-Swing Adsorption Separation of H2S from CO2 with Molecular Sieves 4A, 5A,and 13X

The separation of bulk quantities of H₂S from CO₂ was investigated through a series of pressure-swing adsorption experiments utilizing 4A, 5A, and 13X molecular sieves. High selectivity of H₂S over CO₂ was encountered for all sieves, particularly for the 13X and 5A. Practically pure CO₂ was produced in the adsorption stage with fresh 5A and 13X sieves, at high product recovery rates. Efficient H₂S purification was obtained with fresh 5A and regenerated 4A zeolites. The experimental results were in line with theoretical predictions of the literature.     

Reduction of Biocide-Polluted Wastewater Using O3 and H2O2/O3 Oxidation Processes

The objective of the presented study was to test various oxidation processes with the aim being to reduce the concentration and toxicity of biocide wastewater from a Slovenian phytopharmaceutical factory. Laboratory-scale experiments employing two AOP processes – ozonation (O₃) and peroxone (H₂O₂/O₃) – were applied to reduce the concentration of the active components involved, i.e., methylisothiazolone (MI), chloromethylisothiazolone (CMI) and dichloromethylisothiazolone (DCMI). The reduction of the biocide wastewater load for the performed oxidation processes was evaluated using ecological parameters. The H₂O₂/O₃ oxidation procedure using an O₃ flow rate of 1g/L h, at a pH value of 10 and with the addition of 5 ml of H₂O₂ (0.3 M) proved to be the most effective treatment. The toxicity of the biocide-load wastewater with an initial EC₅₀ = 0.38%, decreased to EC₅₀ (24h) >100% and EC₅₀ (48h) = 76%.     

Complexes in the Photocatalytic Reaction of CO(2) and H(2)O: Theoretical Studies

Complexes (H(2)O/CO(2), e-(H(2)O/CO(2)) and h(+)-(H(2)O/CO(2))) in the reaction system of CO(2) photoreduction with H(2)O were researched by B3LYP and MP2 methods along with natural bond orbital (NBO) analysis. Geometries of these complexes were optimized and frequencies analysis performed. H(2)O/CO(2) captured photo-induced electron and hole produced e-(H(2)O/CO(2)) and h(+)-(H(2)O/CO(2)), respectively. The results revealed that CO(2) and H(2)O molecules could be activated by the photo-induced electrons and holes, and each of these complexes possessed two isomers. Due to the effect of photo-induced electrons, the bond length of C=O and H-O were lengthened, while H-O bonds were shortened, influenced by holes. The infrared (IR) adsorption frequencies of these complexes were different from that of CO(2) and H(2)O, which might be attributed to the synergistic effect and which could not be captured experimentally.     

Synthesis and photocatalytic properties of H2La2Ti3O10/TiO2 intercalated nanomaterial

H₂La₂Ti₃O₁₀/ TiO₂ intercalated nanomaterial was fabricated by successive intercalation reactions of H₂La₂Ti₃O₁₀ with n-C₆H₁₃NH₂/C₂H₅OH mixed solution and acid TiO₂ sol, followed by irradiating with a high-pressure mercury lamp. The intercalated materials possess a gallery height of 0.46 nm and a specific surface area of 31.58 m²·g⁻¹, which indicate the formation of a porous material. H₂La₂Ti₃O₁₀/TiO₂ shows photocatalytic activity for the decomposition of organic dye under irradiation with visible light and the activity of TiO₂ intercalated material was superior to the unsupported one.     

Significant enhancement of the oxidation of CO by H2 and/or H2O on a FeO x /Pt/TiO2 catalyst

Oxidation of CO on the FeO _x /Pt/TiO₂ catalyst is markedly enhanced by H₂ and/or H₂O at 60 °C, but no such enhancement is observed on the Pt/TiO₂ catalyst, but shift reaction (CO + H₂O → H₂ + CO₂) does not occur on the FeO _x /Pt/TiO₂ catalyst at 60 °C. DRIFT-IR spectroscopy reveals that the fraction of bridge bonded CO increases while that of linearly bonded CO decreases on the FeO _x loaded Pt/TiO₂ catalyst. The in-situ DRIFT IR spectra proved that the bridged CO is more reactive than the linearly bonded CO with respect to O₂, and the reaction of the bridge-bonded CO with O₂ as well as of the linearly bonded CO is markedly enhanced by adding H₂ to a flow of CO + O₂. From these results, we deduced that the promoting effect of H₂ and/or H₂O is responsible for the preferential oxidation (PROX) reaction of CO on the FeO _x /Pt/TiO₂ catalyst, and a following new mechanism via the hydroxyl carbonyl or bicarbonate intermediate is proposed for the oxidation of CO in the presence of H₂O.      

The intermolecular interaction studies in the complexes of isothiocyanic acid (HNCS) and its derivatives with H2S: a computational study

The computational investigations are carried out on the complexes of isothiocyanic acid (HNCS) and its derivatives with H₂S through MP2/aug-cc-PVTZ//MP2/aug-cc-PVDZ level. Five, four, three and four structures are located on the potential energy surface of the HNCS?H₂S, HSCN? H₂S, HCNS? H₂S and HSNC?H₂S heterodimers, respectively. The calculated results reveal that the most stable heterodimers among all heterodimers obtained for the HNCS?H₂S, HSCN?H₂S, HCNS?H₂S and HSNC?H₂S systems belong to HSCN?H₂S system. Therefore, HSCN?H₂S system has a key role in the atmosphere.     

Effects of O3, O3/H2O2 and Coagulation on Natural Organic Matter and Arsenic Removal from Typical Northern Serbia Source Water

The objectives of this study were to investigate the effects of ozone and the O₃/H₂O₂ process on FeCl₃ coagulation efficiency for the removal of the high content of natural organic matter (NOM) and arsenic (As) from groundwater (DOC = 9.27 ± 0.92 mg/L; 51.7 ± 16.4 µg As/L). Arsenic and NOM removal mechanisms during coagulation/flocculation are well investigated. However, data concerning arsenic removal in the presence of NOM, which is the subject of this article, are still insufficient. Laboratory and pilot plant test results have shown that the competition of NOM and As for adsorption sites on the coagulant surface have great influence on coagulation/flocculation efficiency for their removal. With both oxidation pre-treatments, arsenic content after the coagulation process was less than 2.0 µg/L in treated water. Application of ozone has a lower influence on coagulation efficacy in terms of DOC reduction, compared to the O₃/H₂O₂ process with the same ozone dose.     

Activation of a Au/TiO2 Catalyst by Loading a Large Amount of Fe–Oxide: Oxidation of CO Enhanced by H2 and H2O

Catalytic activity of a 1 wt% Au/TiO₂ catalyst is markedly improved by loading a large amount of FeO_x, on which the oxidation of CO in excess H₂ is selectively promoted at temperature lower than 60 °C. Oxidation of CO with O₂ on the FeO_x/Au/TiO₂ catalyst is markedly enhanced by H₂, and H₂O moisture also enhances the oxidation of CO but its effect is not so large as the promotion by H₂. We deduced that activation of Au/TiO₂ catalyst by loading FeO_x is not caused by the size effect of Au particles but a new reaction path via hydroxyl carbonyl intermediate is responsible for the superior activity of the FeO_x/Au/TiO₂ catalyst.