几种Fe（Ⅵ）化合物的物理性质、电化学性能及稳定性研究

为深入认识高铁化合物的物理性质和电化学性能,采用化学法合成了K2FeO4、BaFeO4、SrFeO4和 K2Sr(FeO4)2等几种高铁化合物,比较研究了这几种高铁化合物的形貌、结构、在不同浓度KOH溶液中的溶解度 及其放电性能.研究结果显示,在这几种高铁化合物中,BaFeO4具有较好的电化学性能.但在实验过程中发现,除 K2FeO4外,其余几种高铁化合物均不稳定,在干燥环境中放置时会发生分解.采用量子化学从头算方法从理论上 分析了高铁化合物的稳定性变化规律.研究结果表明,高铁化合物的稳定性与阳离子对FeO42-的极化作用有很 大关系,极化作用越强,高铁化合物就越不稳定.     

Keggin结构含钒混配型杂多酸盐及其杂多蓝的极谱和热谱

本文利用极谱和循环伏安的方法研究了杂多酸盐 K3 H2 [Si V Mo2 W9O4 0 ]· 10 H2 O及其一电子杂多蓝 K4 H2 [Si V Mo2 W9O4 0 ]· 12 H2 O和杂多酸盐 K4 H3 [Si V3 W9O4 0 ]· 13H2 O及其两电子杂多蓝 K4 H5[Si V2 V W9O4 0 ]· 11H2 O的氧化还原性质 ,利用 TG- DTA曲线分析了这 4种物质的热稳定性。结果表明杂多酸盐被还原为杂多蓝后 ,氧化能力有所降低 ,但热稳定性增加。     

不同pH酸性溶液中铂电极上氢析出和二氧化碳还原的电化学研究（英文）

本文利用循环伏安法和电化学原位红外光谱的联用,研究了Pt(111)和Pt膜电极在CO_2饱和的酸性溶液中氢析出和CO_2还原的竞争.发现:(i)在pH2的溶液中,主要反应是氢析出,界面pH值随着氢析出突然增加;(ii)通过红外光谱检测,CO_(ad)是CO_2还原过程中唯一的吸附中间体;(iii)CO_(ad)生成速率随着欠电位沉积氢(UPDH)覆盖的增加而增大,并在氢析出的起始电位达到最大值;(iv)在氢析出时,CO_(ad)的减少与CO_2吸附和还原所必需的的中间产物(H_(ad))有限的可用位点和停留时间相关.     

基于紫外-可见光谱法研究叶黄素聚集体结构及其动力学

利用紫外-可见分光光度计,检测了乙醇/水溶液中,不同温度下叶黄素吸收谱,并探测了光谱随时间的变化。结果表明,在1∶1乙醇/水溶液中,高浓度和低浓度样品中,叶黄素H-聚集体随温度升高呈线性降低规律。1∶2溶液中,叶黄素聚集结构不随温度变化而变化,结构稳定。对其吸收光谱的动力学检测发现,1∶1溶液中,随着时间的推移,H-聚集体呈指数增加。分析认为,溶液中水分子的氢键是形成叶黄素聚集结构的决定因素,水分子和氢键数目的增加促使叶黄素形成稳定的H-聚集结构。     

BaFeO4在干燥环境中的分解机理

为深入了解BaFeO4在干燥环境中的稳定性及分解机理,采用恒流放电、X射线光电子能谱(XPS)、X射线衍射(XRD)、红外吸收光谱(IR)等测试手段研究了BaFeO4在不同处理方法后的放电性能和结构性质.恒流放电结果显示,BaFeO4的放电性能随着其放置时间的延长而不断降低;XPS结果证实BaFeO4样品在干燥环境中放置时会逐渐分解为低价态铁盐,并讨论了其可能分解机理.     

表面活性剂溶液粗粒化模型couette流动模拟

本文主要利用粗粒化分子动力学方法对不同浓度下表面活性剂水溶液在couette流动过程中胶束的形成、速度分布与流变性规律进行了研究。结果表明,对于相同浓度的表面活性剂溶液,随着剪切速率的增大,胶束完全动态平衡时间越来越小;而随着表面活性剂分子浓度的增加,胶束动态平衡时间也越来越小,形成胶束越来越快。在剪切速率与溶液剪切黏度关系方面,保持表面活性剂分子浓度不变情况下,随着剪切速率的增大,剪切黏度逐渐减小,呈现剪切稀化特征。     

不同pH酸性溶液中铂电极上氢析出和二氧化碳还原的电化学研究

本文利用循环伏安法和电化学原位红外光谱的联用,研究了Pt(111)和Pt膜电极在CO₂饱和的酸性溶液中氢析出和CO₂还原的竞争. 发现：(i)在pH>2的溶液中,主要反应是氢析出,界面pH值随着氢析出突然增加;(ii)通过红外光谱检测,CO_ad是CO₂还原过程中唯一的吸附中间体;(iii)CO_ad生成速率随着欠电位沉积氢(UPD-H)覆盖的增加而增大,并在氢析出的起始电位达到最大值;(iv)在氢析出时,CO_ad的减少与CO₂吸附和还原所必需的的中间产物(H_ad)有限的可用位点和停留时间相关.     

Fe-MOF电极材料的合成及电性能

通过溶剂热法合成出Fe-MOF材料并进行了XRD表征,结果显示Fe-MOF的XRD衍射峰位置和强度都与已知同类型的MOF结构相似,且没有其他晶相出现;在不同扫描速率下测得的循环伏安具有明显的还原电流峰和氧化电流峰,表现出典型的法拉第氧化还原特性;随着扫描速率的增大,比电容急速下降,Fe-MOF结构可能发生扭曲;500次循环实验结果表明,Fe-MOF比容量没有出现明显的衰减,具有良好的循环寿命.     

水杨醛氨基酸席夫碱水溶液的电子光谱研究

通过电子光谱研究了7种水杨醛氨基酸席夫碱配体Sal-aa在水溶液中的生成情况。Sal-tyr的生成浓度下限为10-5 mol·L-1,其余6种Sal-aa的生成浓度下限均为10-4 mol·L-1。除Sal-his的生成pH为9～10外,其余6种Sal-aa都是pH值增大有利于席夫碱生成。Sal-gly和Sal-tyr的生成pH下限为8,其余4种Sal-aa的pH下限为9。Sal-cys水溶液放置36 h后席夫碱浓度比新生成溶液的大,其余6种Sal-aa都是自生成后就开始缓慢分解。Sal-gly和Sal-glu水溶液的相对稳定存在时间为24 h,其余4种Sal-aa的相对稳定存在时间为48 h。本工作为探索用于放射性药物研究的水杨醛氨基酸席夫碱水溶液标记放射性核素提供了实验基础。     

Al(OH)3溶胶浓度对TC4钛合金微弧氧化膜特性的影响

利用自制多功能微弧氧化(MAO)电源,在保持电学参数和处理时间不变的条件下对TC4钛合金表面进行了MAO处理,研究了Al(OH)₃溶胶浓度对钛合金MAO膜的生长特性、微观结构、相结构和电致变色特性的影响.结果表明:随着Al(OH)₃溶胶浓度(体积分数)C的增加,膜层的生长速率由慢到快逐渐增加,膜表面微孔尺寸和粗糙度逐渐增大,而微孔密度逐渐减小;当C≤10%时,膜层由锐钛矿相TiO₂组成,而当C>10%时,膜层中开始出现金红石相TiO₂并随着C的增加其相对含量逐渐增大,并在C=40%时,膜层全部由金红石相TiO₂组成;在pH＝2.0的HCl溶液中的循环伏安测试结果表明,C≤20%制备试样的膜层颜色变化不明显,随着C的进一步增加,制备试样的膜层颜色变化逐渐明显,并在C=40%时,其着色呈蓝色且色泽均匀;该试样在循环伏安测试过程中还表现出了良好的稳定性和可逆性. 关键词： 微弧氧化 氧化膜 微观结构 电致变色     

Effect of Added Monosodium Glutamate on Characteristics of Polyamide Dope Solutions

Formic acid (FA) solutions prepared with various concentrations of polyamide 66 (PA 66) and monosodium glutamate (MSG) were evaluated in terms of properties, such as density, viscosity, and cloud point. The influence on density was insignificant, whereas the viscosity was strongly affected by the amount of PA 66 and MSG additive. The solutions were further evaluated by casting them in a flat film form and determining the demixing time in a humid atmosphere. The considered cases at lower polymer concentrations at various MSG amounts, indicated that the demixing time increased with increase in polymer concentration. The time for demixing, however, decreased for a given higher amount of polymer when the amount of additive was increased in the dope solution. Membranes were prepared at various coagulant bath temperatures. The tensile strength and degree of adsorption (DOA) of these membranes were found. The tensile strength was higher when the membranes were prepared at higher temperature. The DOA, on the other hand, was higher for the membranes formed at lower temperature.     

聚丙烯胺稳定铜纳米粒子的制备及其SERS活性研究

报道了聚丙烯胺稳定的球形和棒状铜纳米粒子的制备方法。在水溶液中空气条件下,通过水合肼还原二价铜离子到铜纳米粒子。聚丙烯胺的作用除稳定粒子防止聚集外,也可使粒子分散在水溶液中。该法的优点是在室温下,无需惰性气体保护,即可制备水溶液中分散的铜纳米粒子。紫外光谱和透射电镜监测了铜纳米粒子的生长过程。发现氢氧化钠的用量,聚丙烯胺浓度,反应时间等因素都影响到铜纳米粒子的组成,尺寸,形貌和聚集程度。氢氧化钠用量决定了制备粒子的组成成分是铜或氧化亚铜。所制备的球形铜纳米粒子表现出优良的表面增强拉曼散射活性。     

高铁酸钾制备新方法与光谱表征

以次氯酸钙为原料制备了高纯度高铁酸钾,研究内容包括:高铁酸钾的性质反应温度对产率的影响,重结晶温度对产率的影响,反应时间对产率的影响,次氯酸钙用量对产率的影响。确定了反应温度为25℃,重结晶温度为0℃,反应时间为40 min,反应所需的次氯酸钙用量为理论用量的1.2倍,产率为75%以上。利用直接分光光度法对产物纯度进行了分析,测得产物纯度达到92%以上。论文以红外光谱法、紫外分光光度法、X衍射法对产物进行表征,证明以次氯酸钙为原料制得的产物为高铁酸钾。     

Shock wave emission from laser-induced cavitation bubbles in polymer solutions

The role of extensional viscosity on the acoustic emission from laser-induced cavitation bubbles in polymer solutions and near a rigid boundary is investigated by acoustic measurements. The polymer solutions consist of a 0.5% polyacrylamide (PAM) aqueous solution with a strong elastic component and a 0.5% carboxymethylcellulose (CMC) aqueous solution with a weak elastic component. A reduction of the maximum amplitude of the shock wave pressure and a prolongation of the oscillation period of the bubble were found in the elastic PAM solution. It might be caused by an increased resistance to extensional flow which is conferred upon the liquid by the polymer additive. In both polymer solutions, however, the shock pressure decays proportionally to r⁻¹ with increasing distance r from the emission centre.     

Chemical effect of swirling jet-induced cavitation: degradation of rhodamine B in aqueous solution

The chemical effect of swirling jet-induced cavitation was investigated with the decomposing reaction of rhodamine B in aqueous solution. It was found that rhodamine B in aqueous solution can be degraded with swirling jet-induced cavitation and the degradation can be described by a pseudo-first-order kinetics. The effects of operating conditions such as pressure, temperature, initial concentration of rhodamine B, pH of water on the degradation rate of rhodamine B were discussed. It was found that the degradation rate of rhodamine B increased with increasing pressure and decreased with increasing initial concentration. It was also found that the degradation of rhodamine B was strongly dependent of temperature and pH of aqueous solution. The oxidation efficiency of swirling jet-induced cavitation for rhodamine B degradation was discussed and compared with ultrasonic cavitation. The result indicated that the swirling jet-induced cavitation is more energy efficient as compared to sonochemical cavitation.     

Calculation of the rate constant for the ultrasonic degradation of aqueous solutions of polyvinyl alcohol by viscometry

Ultrasonic degradation of polyvinyl alcohol (PVA) was carried out in aqueous solution at 25 degrees C. In this experiment, the effect of solution concentration on the rate of degradation was investigated. Kinetics of degradation was studied by viscometry method. The calculated rate constants indicate that degradation rate of PVA solutions decreases with increasing of solution concentration (C= g lit(-1)). The calculated rate constants correlated in terms of reverse concentration and relative viscosity of PVA solutions. This behavior in the rate of degradation was interpreted in terms of viscosity and concentration of polymer solution. With increasing solution concentration, viscosity increases and it causes a reduction in the cavitation efficiency thus, the rate of degradation will be decreased.     

Probing the role of hydrolytically stable, 3-aminopropyl triethoxysilane crosslinked chitosan/graphene oxide membrane towards Congo red dye adsorption

In this investigation, the practicability of utilizing 3-aminopropyl triethoxysilane (3-APTES) crosslinked chitosan (Ch)/graphene oxide (GO) membranes were explored for adsorptive removal of anionic dyes from aqueous medium. Membranes were successfully fabricated through solution casting technique. Strong interactions amongst matrix (chitosan), 3-APTES, polyvinylpyrrolidone (PVP) and GO were confirmed by Infrared spectroscopy. Thermal stability of the chitosan was improved by adding graphene oxide and results were verified via thermogravimetric (TGA) analysis. Swelling and hydrolytic results confirmed that 2 %-Ch/PVP was a stable membrane while increasing the amount of 3-APTES in the chitosan nanocomposites membrane decreased its stability in aqueous medium. The adsorption characteristics of the membranes were evaluated by the adsorption of Congo red (CR) dye from aqueous medium. The adsorbent can remove 80% of CR from aqueous medium and follows second order kinetics. This study outlines the possibility of exploring green membranes which can be easily fit in various flow systems.     

Ultrasound assisted preparation of water in oil emulsions and their application in arsenic (V) removal from water in an emulsion liquid membrane process

Water in oil emulsions are prepared by using an ultra-sonication device and used in an emulsion liquid membrane process in order to recover arsenic (V) ions from an aqueous medium. The aim of this work is the investigation of the effect of emulsifier concentration and composition, and also sonication time on the emulsion droplet size and the extraction efficiency in order to obtain stable emulsions with small droplets that favor the extraction. Results show that ultrasonic waves reduce internal droplet size which enhances the extraction of arsenic. In addition, internal droplet size is decreased initially and then increased by increasing Span 80 concentration. On the other hand, by increasing Span 80 concentration, extraction amount is increased and then decreased. Furthermore, emulsifier blends provide more stability for the emulsion. Increasing concentration of Tween 20 as a hydrophilic emulsifier up to an optimum concentration decreases internal droplet size and increases extraction amount. By increasing sonication time up to 4 min, the internal droplet size is decreased and the extraction amount is increased. If sonication time is increased further, the internal droplet size is increased and the extraction amount is decreased.     

Swelling and Gelation Time Behavior of Sulfonated Polyacrylamide/Chromium Triacetate Hydrogels

A hydrogel was prepared by crosslinking of aqueous solutions of sulfonated polyacrylamide/chromium triacetate for use in water shut-off operations in oil reservoirs. The effects of pH, salinity, retarder and temperature, as well as co-polymer and crosslinker concentration, on the gelation time were investigated. The results indicated that as temperature increased, gelation occurred more rapidly. The activation energy was measured as about 86 kJ/mol. The effects of initial pH and retarder on the gelation time were also examined. The results showed that addition of retarder and increasing of pH increased and decreased the gelation time, respectively. The increase of co-polymer concentration in solution increased the gel swelling. However, the increase of crosslinker concentration decreased the gel swelling. In the presence of electrolytes, the gel swelling decreased by about 80%. Finally, some usable practical recommendations are offered for the gelling systems in reservoirs.     

Improvement in properties of coal water slurry by combined use of new additive and ultrasonic irradiation

Coal water slurry (CWS) was prepared with a newly developed additive from naphthalene oil. The effects of ultrasonic irradiation on coal particle size distribution (PSD), adsorption behavior of additive in coal particles and the characteristics of CWS were investigated. Results showed that ultrasonic irradiation led to a higher proportion of fine coal in CWS and increased the saturated adsorption amount of additive in coal particles. In addition, the rheological behavior and static stability of CWS irradiated by ultrasonic wave were remarkably improved. The changes on viscosity of CWS containing 1% and 2% additive are qualitatively different with the increasing sonication time studied. The reason for the different effect of sonication time on CWS viscosity is presented in this study.