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。     

Characterization of polypyrrole films electrosynthesized onto titanium in the presence of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)

Films of polypyrrole (PPy) were successfully electrosynthesized onto titanium in neutral and alkaline solutions of sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol OT or AOT) by potentiodynamic, galvanostatic and potentiostatic techniques. Results of the characterization of the films by cyclic voltammetry, scanning electron microscopy (SEM) and adhesion measurements are presented. It was found that the AOT molecule remains entrapped within the polymer matrix. The initial growth of the polymer produces electroactive toroidal deposits whereas for electropolymerization of longer duration the typical globular structure is developed. Adherence to Ti increases with deposition time and this result is interpreted as a consequence of the growth of a composite PPy/Ti oxide.     

O/W型微乳液对槲皮素增溶作用的研究

考察了吐温-80/正丁醇/丁酸乙酯/水微乳液体系对水难溶性药物槲皮素的增溶作用。结果表明,槲皮素在以丁酸乙酯为油相的微乳液和其相应的胶束溶液中溶解度明显增大。同时随着载药微乳液浓度的增加,微乳液的粒径有增大趋势;而随着放置时间的延长,粒径有减小的趋势。在对载药微乳液稳定性的考察中发现,载药微乳液在室温和低温下放置比较稳定,其外观性状和药物含量均没有明显变化。     

The factors affecting the backward-transfer of Bovine Serum Albumin (BSA) from sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micellar solutions

The factors affecting the back-extraction efficiency of Bovine Serum Albumin (BSA, 65kDa, pI 4.9) solubilized in an AOT reverse micellar solution, prepared by the injection method, to an excess aqueous phase were investigated. In particular, effects of pH, the type of salt and its concentration in the excess aqueous phase were examined. Furthermore, by comparing CD spectra of the back-extracted BSA with the feed BSA, the structural changes of the protein during the extraction process were determined. The addition of 1:1 salt such as KCl or NaCl to the aqueous phase resulted in a 100% recovery of the protein to the aqueous phase at a pH higher than its isoelectric point pI. This high efficiency of the back-extraction might be due to the change in the interactions between the protein and micellar aggregates driven by the added salt. For 1 : 2 salts like MgCl₂ or CaCl₂, BSA was back extracted with lower than 20% extraction efficiency. Maximum efficiencies were achieved at about pH=7 and pH=8 for monovalent and divalent salts, respectively. From the C D spectra of back-extracted BSA, it was observed that denaturation of BSA was not significant during the extraction process.     

Effect of additives on the adsorption of sodium bis(2-ethyl hexyl sulfosuccinate) at the air-water interface studied by equilibrium and dynamic surface tension measurements

Using equilibrium and dynamic surface tension measurements, we have studied the effect of the addition of poly(sodium 4-styrenesulfonate) (PSS), sodium chloride, and 1,4,7,10,13,16-hexaoxyacyclooctadecane (18-crown-6) on the surface properties of sodium bis(2-ethyl hexyl sulfosuccinate) (AOT). The addition of PSS or NaCl weakly increases the maximum packing of AOT, whereas the presence of 18-crown-6 slightly decreases the maximum surface coverage. The surfactant adsorption kinetics on the interface is a diffusion-controlled process. The two asymptotic solutions at long times and at short times to the classic Ward Tordai equation were used to fit dynamic results. At long times there is evidence of the existence of an electrostatic barrier at high surfactant concentration when using pure AOT and AOT mixed with PSS. In binary mixtures of AOT with sodium chloride or 18-crown-6, the electrostatic barrier is not observed over the surfactant concentration range studied.     

季铵盐体系金的萃取与反萃

在碱性条件下研究了十六烷基三甲基溴化铵(CTAB)微乳液体系萃取KAu(CN)2. 实验考察了水相金浓度、反萃液中卤素离子、NH4SCN及羟乙基硫醚浓度对金萃取和反萃的影响及有机相中水含量与金萃取的关系. 结果表明：CTAB/己醇/庚烷微乳液体系可将绝大部分金从水相萃取到有机相;随着萃入金的增加,有机相水含量减少. 卤素离子的反萃能力顺序为：KI>KBr>KCl;高KI浓度(>2.0 mol/L)可将有机相中绝大部分(94%)的金反萃出来. 羟乙基硫醚及NH4SCN也是金的良好反萃剂,两者混合可以降低反萃液粘度,又可以减小NH4SCN浓度,而保持较高的金反萃率.     

Design of a super-hydrophilic/super-oleophobic g-C3N4/Ti(OH)4/PFOA nanocomposite coated mesh as a smart nanofilter with robust anti-fouling properties for separation of oil and water emulsions

The design and development of efficient approaches for water–oil separation have had widespread interest. This study aimed to synthesize nanocomposites based on Ti(OH)₄ and g-C₃N₄ nanosheets (CN-NS) to show experimentally that the inclusion of Ti(OH)₄ nanoparticles of 9.2 nm size into CN-NS leads to an improved oil-water separation efficiency and anti-fouling performance. So, a novel, reusable, and recyclable super-hydrophilic/underwater super-oleophobic CN-NS/Ti(OH)₄ nanocomposite-coated stainless steel mesh was developed to separate oil-in-water emulsions. Super-wettability was obtained in the CN-NS/Ti(OH)₄ nanocomposite with WCA = 0° and UOCA = 154°, respectively, showing significant super-hydrophilicity and underwater super-oleophobicity. Surface hydrophilicity increased after anchoring Ti(OH)₄ on the CN-NS surface, resulting from oxygen-containing functional groups and consequently making defects on the mesh surface. Enhanced underwater oleophobicity of nanocomposite coated mesh is attributed to its higher surface roughness, which is a result of its micro-nano meter and mesoporous hierarchical structure. Moreover, the self-cleaning property of the as-prepared mesh was demonstrated by visible light irradiation on the contaminated mesh. In addition, perfluorooctanoic acid (PFOA) reduced energy in CN-NS/Ti(OH)₄/PFOA mesh, resulting in a super-hydrophilic/super-oleophobic mesh. The CN-NS/Ti(OH)₄/PFOA nanocomposite-coated filter was observed to separate water from a 1 wt% water-in-oil emulsion at 0.2 bar pressure with a filtration flux of 317.2 L m⁻² h⁻¹ and 95% separation efficiency.     

AgBr/Zn3(OH)2V2O7·2H2O可见光催化降解亚甲基蓝溶液

采用水热和沉淀两步合成法制备AgBr/Zn₃(OH)₂V₂O₇·2H₂O催化剂,研究其在可见光下降解亚甲基蓝溶液的性能,并考察催化剂用量、亚甲基蓝溶液初始浓度、pH值以及盐浓度对光催化性能的影响,评价AgBr/Zn₃(OH)₂V₂O₇·2H₂O催化剂的重复使用性能。结果表明,在前驱液pH为10、120 ℃水热10 h、Ag与Br物质的量比为0.20条件下制备的复合催化剂在可见光下反应120 min后,1.0 g·L^-1的催化剂对10 mg·L^-1的亚甲基蓝溶液脱色率达到85.2%。NaCl对亚甲基蓝的降解起抑制作用,Na₂SO₄对亚甲基蓝的降解起促进作用。催化剂重复使用4次后,光照120 min后的亚甲基蓝溶液脱色率可达66.4%。催化剂对不同初始浓度亚甲基蓝溶液的光催化降解符合一级动力学模型。     

Preparation of W1/O/W2 emulsions and droplet size distribution measurements by pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) technique

Multiple emulsions of W₁/O/W₂ type are of major interest in life sciences, offering possibilities for the encapsulation of water‐soluble active agents. In food science, they are also applied for fat reduction. The droplet size distributions of the inner and outer emulsions are of main importance as they influence the rheological and sensorial properties, the release kinetics, as well as the structural and microbial stability. However, the determination of the inner and outer droplet size distributions is a major challenge, as conventional measurement techniques cannot be applied. Pulsed‐field gradient nuclear magnetic resonance (PFG‐NMR) is well known as a non‐destructive tool for droplet size determination, especially in simple emulsions. In this work, double emulsions of the W₁/O/W₂ type were prepared with polyglycerol‐polyricinoleate (PGPR) and polyoxyethylen‐20‐sorbitan monolaurate (Tween 20) as emulsifiers by means of rotor‐stator emulsification machines. PFG‐NMR was applied for measurements of the inner phase (W₁) droplet size distribution as well as for the characterization of the O phase. The W₁ values were compared with results from laser light diffraction of simple emulsions (W₁/O type) and were found to be consistent within the experimental errors, if restricted diffusion in the outer water phase (W₂) and additional effects are considered.     

Degradation of benzene,toluene ethylbenzene and p‐xylene (BTEX) in aqueous solutions using UV/H2O2 system

The homogeneous degradation of benzene (B), toluene (T), ethylbenzene (E) and p‐xylene (X) (BTEX) was studied in aqueous solutions, at pH 3.0, of hydrogen peroxide (5.8 mM ) under UV irradiation in a photoreactor equipped with a 300 nm lamp of light intensity 3.5 × 10^?5 Ein L^?1 min^?1. BTEX was substantially degraded by the H₂O₂/UV system, with >90% disappearing in 10 min of irradiation. The decomposition of BTEX was studied either as single or as multi‐component systems. The effects of irradiation time, amounts of H₂O₂ in molar ratios, rate of degradation and competition between components were thoroughly examined. It can be stated that the rate of BTEX degradation in mixture was higher than those for the individual components due to external effects of the absorption of UV light by the mixture, and their effects on enhancing the formation of OH^? radicals. The appropriate figure of merit, the electrical energy per mass (EE/M), was estimated at various molar ratios and it was confirmed that the best value was the one depicted for p‐xylene (0.065 kWh kg^?1). A theoretical model for the degradation pathway was proposed. Copyright © 2004 Society of Chemical Industry     

Effect of dye auxiliaries on the kinetics of advanced oxidation UV/H2O2 of Acid Orange 7 (AO7)

BACKGROUND: The effect of four dye‐auxiliary chemicals, typically employed in acid dyeing, on the performance of UV/H₂O₂ decolouration of the model non‐biodegradable dye C.I. Acid Orange 7 (AO7) was investigated. The initial concentration of AO7 was 0.150 g L^?1, while the concentration of the auxiliary compounds (NaCl, Na₂SO₄, Na₂CO₃ and CH₃COOH) was varied in the range 1–10 g L^?1. RESULTS: The negative influence of the presence of the dye‐auxiliary compounds studied on the decolouration rate of AO7 decreased in the following order: CH₃COOH > Na₂SO₄ > NaCl > Na₂CO₃. Results were quantified in terms of the observed kinetic rate constant, k_obs (s^?1), of AO7 decolouration as a function of dye auxiliary chemical concentration. The decolouration rate of AO7 decreased as the concentration of dye‐auxiliary compound increased in the range 1–5 g L^?1, while higher concentrations had a minor effect. Upon addition of 5 g L^?1 of CH₃COOH, NaCl and Na₂SO₄, the kinetic rate constant decreased by 39%, 30% and 12%, respectively. CONCLUSIONS: It was concluded that the presence of NaCl, Na₂SO₄ and above all of CH₃COOH should be considered in the design of the treatment of real dye‐bath effluents by UV/H₂O₂. Copyright © 2008 Society of Chemical Industry     

Fe2+协同H2O2/O3氧化降解水中邻苯二甲酸二甲酯

采用Fe2+协同H2O2/O3氧化处理水中的邻苯二甲酸二甲酯(DMP),研究表明Fe2+的存在消除了H2O2对O3的抑制作用,并使H2O2/O3对DMP的去除率大幅提高了31.75％.DMP质量浓度为50 mg/L、初始pH为10、H2O2投加量为0.049 mol/L、O3投加量为1.82 g/h、Fe2+投加量为0...     

Evolution of magnetic order in multiferroic Pb(Fe2/3W1/3)O3-BiFeO3 solid solution

Multiferroic materials have attracted much interest in the last decade due to both the intriguing fundamental science and the potential applications in spintronics and magnetoelectric data storage devices. In this work, we have investigated and discussed the evolution of the magnetic properties of the multiferroic (1-x)Pb(Fe_2/3 W_1/3)O₃-xBiFeO₃ solid solution ((1-x)PFW-xBFO, x = 0, 0.025, 0.05, 0.075, 0.1 and 0.15). The magnetic phase diagram is established based on the magnetic measurement results, which reveals six magnetically ordered states on the PFW-rich side of the solid solution. The origins of the complex evolution of magnetic order in the PFW-BFO solid solution are discussed from the point view of the variations in both the –Fe–O–Fe– and –Fe–O–W–O–Fe– superexchange routes, which are intimately related to the ratio of magnetic Fe³⁺ ion concentration on the B-site and the changes in the local structural order/disorder and chemical homogeneities. Combining the magnetic phase diagram with the relaxor characteristic phase diagram of the (1-x)PFW-xBFO system, a striking feature is found that the ergodic relaxor (ER) state and the weakly ferromagnetic phase coexist in the composition range of 0.025 ≤ x ≤ 0.1 between the freezing temperature T_f and the Burns temperature T_B.     

H6P2M09W9O62/Zn(BDC)(Bipy)0.5复合材料催化合成3,4-二氢嘧啶-2(H)酮衍生物

采用水热法分别合成杂多酸H6P2Mo9W9O62及有机金属骨架Zn(BDC) (Bipy)0.5,使用浸渍法合成H6P2Mo9W9O62/Zn(BDC) (Bipy)05复合材料,用该复合材料催化醛、乙酰乙酸乙酯和尿素通过Biginelli反应,乙醇作溶剂,合成6种3,4-二氢嘧啶-2(H)酮衍生物.通过IR、1HNMR、13CNMR确定其结构,通过m.p.确定其纯度.实验结果表明:固定醛用量为0.04 mol,n(醛)∶n(乙酰乙酸乙酯)∶n(尿素)=1∶1.4∶1.5,2.0 wt％ H6P2Mo9W9O62/Zn(BDC)(Bipy)0.5,反应温度为105℃,反应时间为60 min时,产物收率为40.1％～91.5％.     

Catalytic activities of Co(Ni)Mo/TiO2–Al2O3 catalysts in gasoil and thiophene HDS and pyridine HDN: effect of the TiO2–Al2O3 composition

The effect of the TiO₂–Al₂O₃ mixed oxide support composition on the hydrodesulfurization (HDS) of gasoil and the simultaneous HDS and hydrodenitrogenation (HDN) of gasoil+pyridine was studied over two series of CoMo and NiMo catalysts. The intrinsic activities for gasoil HDS and pyridine HDN were significantly increased by increasing the amount of TiO₂ into the support, and particularly over rich- and pure-TiO₂-based catalysts. It is suggested that the increase in activity be due to an improvement in reducing and sulfiding of molybdena over TiO₂. The inhibiting effect of pyridine on gasoil HDS was found to be similar for all the catalysts, i.e., was independent of the support composition. The ranking of the catalysts for the gasoil HDS test differed from that obtained for the thiophene test at different hydrogen pressures. In the case of gasoil HDS, the activity increases with TiO₂ content and large differences are observed between the catalysts supported on pure Al₂O₃ and pure TiO₂. In contrast, in the case of the thiophene test, the pure Al₂O₃-based catalyst appeared relatively more active than the catalysts supported on mixed oxides. Also, in the thiophene test the difference in intrinsic activity between the pure Al₂O₃-based catalyst appeared relatively more active than the catalysts supported on mixed oxides. Also in the thiophene test, the difference in intrinsic activity between the pure Al₂O₃- and pure TiO₂-based catalysts is relatively small and dependent on the H₂ pressure used. Such differences in activity trend among the gasoil and the thiophene tests are due to a different sensitivity of the catalysts (by different support or promoter) to the experimental conditions used. The results of the effect of the H₂ partial pressure on the thiophene HDS, and on the effect of H₂S concentration on gasoil HDS demonstrate the importance of these parameters, in addition to the nature of the reactant, to perform an adequate catalyst ranking.     

电感耦合等离子发射光谱法测定Pt/Al_2O_3催化剂中的Pt

用电感耦合等离子发射光谱法测定了Al2O3基催化剂中的Pt,考察了基体及所用试剂对Pt测定的影响,发现Al2O3基体、硫酸等对Pt测定均有负干扰,应在标准溶液与基体匹配的情况下进行测定。该方法的检出限为Pt0.10mg/L;样品的加标回收率96%以上。     

Coke study on MgO-promoted Ni/Al2O3 catalyst in combined H2O and CO2 reforming of methane for gas to liquid (GTL) process

MgO-promoted Ni/Al₂O₃ catalysts have been investigated with respect to catalytic activity and coke formation in combined steam and carbon dioxide reforming of methane (CSCRM) to develop a highly active and stable catalyst for gas to liquid (GTL) processes. Ni/Al₂O₃ catalysts were promoted through varying the MgO content by the incipient wetness method. X-ray diffraction (XRD), BET surface area, H₂-temperature programmed reduction (TPR), H₂-chemisorption and CO₂-temperature programmed desorption (TPD) were used to observe the characteristics of the prepared catalysts. The coke formation and amount in used catalysts were examined by SEM and TGA, respectively. H₂/CO ratio of 2 was achieved in CSCRM by controlling the feed H₂O/CO₂ ratio. The catalysts prepared with 20 wt.% MgO exhibit the highest catalytic performance and have high coke resistance in CSCRM. MgO promotion forms MgAl₂O₄ spinel phase, which is stable at high temperatures and effectively prevents coke formation by increasing the CO₂ adsorption due to the increase in base strength on the surface of catalyst.     

Graft copolymerization of 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid onto carboxymethylcellulose (sodium salt) by H2O2/Fe+2 redox pair

The effect of the reaction conditions on the grafting parameters during grafting of 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid onto sodium carboxymethylcellulose using H₂O₂/Fe⁺² redox pair are studied at 30°C. The grafting ratio, add on, and conversion initially increase with the H₂O₂ concentration in the range of (10.0–15.0) × 10^?2 mol dm^?3. Thereafter, these parameters decrease with the H₂O₂ concentration. The grafting ratio, add on, and conversion increase when increasing the ferrous ion concentration from (0.5 to 4.0) × 10^?2 mol dm^?3 and decrease with a further increase in the concentration. It is observed that the grafting ratio and add on increase with the monomer concentration, whereas the conversion decrease. The hydrogen ions seem to be facilitating the grafting reaction up to a certain concentration and after this concentration seem to be retarding the process. The grafting ratio, add on, and conversion decrease with the sodium carboxymethylcellulose concentration. When increasing the time period from 60 to 90 min, the grafting parameters increase but decrease thereafter. Similarly, when increasing the temperature from 25 to 30°C, the grafting parameters increase and decrease thereafter. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4819–4825, 2006     

Double perovskite Pr2−xBixSr2O6 (x = 0.533) in ketonization of 1-butanol: Effect of water vapor addition

An effective ketonization of 1-butanol mixed with water vapor over the catalyst Pr_1.467Bi_0.533Sr₂O_5.928 of monoclinically distorted perovskite structure is reported. The catalyst is characteristic of 1.2 at.% of oxygen vacancies, supposed to act as active centers of Lewis type, and of a high oxidative ability reflected by large change in the catalyst's effective valence factor (V-3). The ketonization performed without water addition is accompanied with total carbonization of 1-butanol, caused by the catalyst's oxygen, the latter easily releasable beginning from low temperatures. This negative effect is practically removable if the process is performed under the presence of water vapor. It is also found that water addition influences the formation of C₃H₇–CHO aldehyde and of C₃H₇–CO–C₃H₇ ketone. Nevertheless, water addition leads to a steady destruction of the catalyst's crystal structure because of CO₂, appearing in course of the WGSR process, and of its subsequent reaction with the structure component SrO to SrCO₃. The catalyst is found easily reproducible by its re-oxidation in air at 850–900 °C.