Span80-Tween-菜油-水乳化体系中最佳HLB值与乳化剂总用量的关系

将失水山梨醇单油酸酯 ( Span80 )分别和四种聚氧乙烯 ( 2 0 )失水山梨醇酯 ( Tween2 0 ,Tween40 ,Tween6 0 ,Tween80 )按各种比例复配 ,在不同乳化剂总用量下乳化固定比例菜油—水体系 ,用分散相的相对体积分布来评价乳状液的稳定性 ,研究乳化剂总用量对最佳 HLB值的影响。实验发现 :Span80 - Tween2 0体系在较高总用量下在较宽 HLB值范围内均能获得较稳定乳状液 ;Span80 - Tween40、Span80 - Tween6 0和 Span80 - Tween80体系则随乳化剂用量增大而最佳 HL B值范围变窄 ,且有一个最佳乳化剂总用量 ,乳化剂总用量过高时乳状液稳定性反而下降 ;随乳化剂总用量增大 ,Span80 - Tween2 0和 Span80 - Tween6 0体系的最佳 HL B值均发生右移。文中对各种不同实验现象作出了较统一的解释。     

生物柴油-柴油混合燃料的理化及排放特性研究

对生物柴油-柴油混合燃料的表面张力、运动黏度、抗磨性、氧化稳定性以及碳烟排放等特性进行了测试和研究.结果表明,生物柴油-柴油混合燃料的表面张力随生物柴油含量的增加呈抛物线趋势变化,并随温度升高呈幂函数曲线下降.生物柴油的磨斑直径小于柴油,最大卡咬极限压力大于柴油.生物柴油的质量分数为40％-70％,混合燃料的氧化稳定性...     

表面活性剂HLB值与渣油乳化体系分散性及电学性质的关系研究

为了研究表面活性剂亲水亲油平衡值（HLB值）与渣油乳化体系分散性和电学性质的关系,采用粒径和粒径分布相结合的方法来评价乳化体系的分散性,利用电导率值的变化来反应体系电学性质的差异,以表面活性剂B和A复合成实验用渣油乳化分散剂来分散渣油加氢裂化水溶性盐,考察了表面活性剂HLB值对渣油包盐水体系的分散性和电学性质的影响。结果表明,随表面活性剂HLB值从小到大的变化,不同水溶性盐在同种油中的分散性和电学性质不同,同种盐在不同油中的变化也存在着差异。乳化体系的分散性及电学性质随着HLB值的增加呈非线性变化。     

大豆磷脂的HLB值测定和乳化力的研究

建立了测定大豆混合磷脂的HLB值的方法。并做出了不同温度下HLB值的标准曲线。利用此曲线测定了不同PC含量的磷脂的HLB值，PC含量为25．6％～69．9％，其HLB值在7～10之间。研究了不同PC含量的大豆混合磷脂的乳化能力。     

千金子油理化性质及其脂肪酸和挥发油成分分析

对千金子油理化性质进行了系统的分析测试,并利用气相色谱法分析了千金子油脂肪酸及千金子挥发油,结果表明,千金子油中油酸含量最高占78.158%,其次是软脂酸、硬脂酸,分别为8.513%和5.523%;千金子挥发油中油酸、亚油酸和油酸-2-丙三醇酯含量较高,分别为17.747%,15.852%和13.196%.     

生物质热解制备木醋液及其性质研究

对杉木屑、棉杆、竹屑三种生物质热解制得的木醋液产率、基本理化性质及其有机成分进行了分析研究。结果表明,三种生物质原料在350℃下热解制得的粗木醋液、精制木醋液产率相差不大,相同条件下氯化钾浸渍处理后的杉木屑热解所得的粗木醋液、精制木醋液的产率有所降低。三种原料制得的精制木醋液的理化性质不同,杉木屑木醋液的pH值最小,密度最大,竹屑和棉杆木醋液的有机酸含量相对较高。采用GC-MS对精制木醋液中的有机成分进行了分析,结果表明,杉木屑木醋液中的主要组分为酸类、酚类和酮类化合物,棉杆和竹屑木醋液中的主要组分除这三类有机物质外,还含有相对含量较高的醇类化合物。酸类和酚类化合物在三种木醋液中的相对含量依次是竹屑 >棉杆 >木屑;酮类的相对含量依次是木屑 >棉杆 >竹屑。氯化钾处理后的木屑热解所得的木醋液中主要组分酚类和酮类化合物的相对含量有所降低,酸类化合物的相对含量增加,主要表现为乙酸相对含量的增加。与杉木屑木醋液相比,KCl处理后的杉木屑木醋液中的醇类化合物相对含量增加了1倍左右。     

粉煤灰理化性质及改土增产效应研究

研究了粉煤灰的理化性质及改土增产效应。结果表明，粉煤灰颗粒以物理性砂粒为主，含有Ｓｉ、Ｆｅ、Ｐ、Ｋ、Ｃａ、Ｍｇ、Ｚｎ、Ｃｕ、Ｍｏ、Ｂ等作物营养元素；施用粉煤灰能提高土壤物理性砂粒含量，增加土壤孔隙度，降低容量，对粘重土壤具有良好的改土效应。     

成都市城市绿地土壤理化性质研究

对成都市绿地土壤的理化性质进行了研究,并与郊区的土壤作了比较.结果显示,该市绿地土壤的pH明显高于市郊,而有机质含量和总硫含量则低于市郊.     

蛹虫草超氧化物歧化酶理化性质的研究

超氧化物歧化酶[Superoxide d ismutase,SOD,(EC.1.15.1.1)]是广泛存在于生物体内的超氧阴离子自由基(·O2-)的天然清除剂,在机体保护方面起重要作用。在对SOD进行的一系列研究中,发现SOD的存在与生物体抗衰老、抗肿瘤、营养状况、免疫性疾病、炎症及辐射防护[1]有关。许多动植     

垃圾焚烧飞灰浸出特性及理化性质研究

文章研究了福建某垃圾焚烧厂飞灰的化学、矿物学特征以及不同处理工艺对飞灰中重金属脱除效率的影响.结果表明:垃圾焚烧飞灰表面结构复杂,比表面积较小,而飞灰中的碱性氯化物和金属化合物对酸洗处理过程中的浸出效率有明显影响.飞灰中的金属浸出效率与其性质和形态有关.水洗处理可造成飞灰中组成物质和化合物形态的变化,并显著去除飞灰中水...     

The influence of main emulsion components on the physicochemical properties of soursop beverage emulsions: A mixture design approach

The physicochemical properties of soursop beverage emulsion were investigated using mixture design. Results indicated that the regression models were significantly fitted for all response variables studied, except creaming index at 10°C. Interactions between biopolymers and oil phase had the most significant effect on creaming stability; however, modified starch played a much prominent role in maintaining the cloudiness and average droplet size. Meanwhile, WPI contributed significantly to the conductivity of the emulsions. The optimum condition resulted in desirable physicochemical properties could be achieved using 8.70% (w/w) modified starch, 1.02% (w/w) WPI, 10.11% (w/w) flavor oil, and 76.57% (w/w) water.     

生物质快速热解油水相溶液超声乳化特性

使用生物油水相溶液与0# 柴油乳化,筛选了四种常用乳化剂和一种助乳化剂进行复配乳化实验,考察了复配乳化剂型号、乳化剂用量、超声作用时间对乳化效果的影响。结果表明,六种乳化液超过30d不破乳,与0# 柴油相比,密度和热值相差不大,含水量3%以下,黏度增大约40%,pH值降低一半。因素分析法表明,水相溶液与柴油质量比和不同的水相溶液对乳化效果影响较大。探讨了乳化机理,认为生物油水相溶液中水、醛、酸、酮等极性组分化合物稳定地被乳化剂包裹在W/O型乳化液液滴中,生物油水相溶液中少量的乙酸乙酯、芳香类化合物等则增溶于非离子乳化剂胶束中。热力学分析表明,超声乳化作用比静置作用具有更大的熵增,乳化液更趋于稳定平衡状态。     

Influence of the HLB parameter of surfactants on the dispersion properties of brine in residue

In order to study the relationship between the hydrophilic–lipophilic balance of surfactants and the dispersion properties of brine in residue, using droplet size and droplet distribution analytical method were determined on emulsions prepared with emulsifier blends of varying hydrophilic–lipophilic balance (HLB) values the required HLB values of emulsion. The objective of this study was to investigate the effect of HLB on the dispersion properties of brine in residue. The type of emulsion was prepared using emulsifiers with various hydrophilic–lipophilic balance values. The droplet size and droplet distribution varied widely among emulsions containing emulsifiers with different HLB values. The results obtained in this study indicate that the different systems of residue/brine need different HLB values. The HLB value of the emulsion with the least dispersion ratio or the least average droplet diameter was taken as the system of residue/brine required HLB the required HLB values of (NH₄)₆Mo₇O₂₄·4H₂O, Co(NO₃)₂, NiSO₄, Ni(NO₃)₂ and FeSO₄. The results showed that the values of HLB were determined as different system of emulsion.     

生物油/乙醇混合燃料燃烧性能研究

在空气气氛下采用热失重技术研究生物油及其与乙醇混合燃料的燃烧性能,利用Achar微分法和Coats-Redfern积分法结合的方式进行动力学分析,并对热解焦炭的物化特性进行了测量。结果表明,生物油及其与乙醇混合燃料的燃烧可分为三个阶段,即轻组分挥发、重组分裂解和焦炭燃烧;随着升温速率的升高,生物油的挥发性能和燃烧性能提高;随着乙醇质量分数的增加,挥发段和焦炭燃烧段的活化能都呈先减小后增大的趋势;混合燃料中乙醇质量分数不宜超过26%,否则其燃烧段的活化能增大,且热解焦炭所含有机官能团强度变弱,燃烧性能反而变差。     

固体酸改质生物油的研究

利用乙酸和乙醇生成乙酸乙酯的酯化反应为模型反应,筛选得到催化活性最好的固体酸催化剂40％SiO2/TiO2SO42－。 在一定的反应条件下,添加固体酸催化剂和溶剂,生物油的品质得到提高,热值提高了50.7％,运动黏度降低到原来的10％,密度降低了22.6％。生物油改质前后的GC MS分析表明,固体酸可以将生物油中含有的有机羧酸转化为酯类,如甲酸酯、乙酸酯等,使生物油中的羧酸组分发生了催化酯化反应,改善了生物油的品质,生物油物理化学性能得到明显的提高。3A分子筛对生物油的脱水作用不显著,对酸性、密度、黏度等方面影响较小。     

Effect of emulsifier HLB and stabilizer addition on the physical stability of thyme essential oil emulsions

The objective of this work was to formulate and to further improve the stability of emulsions based on thyme essential oil. Several nonionic surfactants of different nature and with different hydrophilic?lipophilic balance (HLB) values were investigated. The surfactant with optimal HLB found for the thyme essential oil was Appyclean 6548 (HLB: 9-9.5). Afterwards, stabilizing biopolymers were added in order to improve emulsion stability. Properties of emulsions were evaluated in terms of droplet size and physical stability. Thyme essential oil/W emulsions formulated with a new biodegradable emulsifier (alkyl polypentoside) and welan gum as stabilizer were obtained with high shelf-life.     

Correlations between topological features and physicochemical properties of molecules

The article reviews in brief, thede novo group additivity approach and, at length, the different topological approaches to obtain predictive and internally consistent correlations between various properties and structural features of molecules. The stress has mainly been on the molecular connectivity method. A new rational scheme for nomenclature of connectivity indices of different orders and types is introduced. The concept of the perturbation connectivity parameter developed by us recently has been applied to obtain correlations for molar refraction, boiling point, molar volume, heat of atomisation, heat of combustion, heat of vaporisation, magnetic susceptibility and critical constants of alkanes, alcohols and alkylbenzenes. A comparative study of various approaches reveals that the present perturbation topological approach has an edge over other similar methods.     

Pore structure and adsorption properties of stone active carbons prepared by physicochemical and chemical activation methods

Active carbons (ACs) with diverse microporous and developed mesoporous structures were prepared by chemical and phisochemical activation methods from walnut shells, fruit stones, and grape seeds. The surface chemistry was studied by chemical titration and spectroscopy in the IR, UV, visible, and near IR regions. The ACs prepared by chemical activation contain carboxyl and phosphate groups, which impart acidic properties to the surface. Basic functional groups are mainly formed on the ACs prepared by physicochemical activation. The AC surface has a complicated chemical composition, which results in high adsorpion activity. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 744–748, May, 2006.     

Salinity and pH as factors affecting the passive sampling and extraction of pharmaceuticals from water

Passive sampling is an attractive technique for the long‐term monitoring of pharmaceuticals in the water environment. The reliability of the received results depends on the properly performed calibration, namely the determination of analyte sampling rates. This step can be the source of a systematic error, as the sampling rate values are dependent on the water donor phase parameters. This is especially important for pharmaceuticals, since their chemical characteristics and ionic form change with pH. In this study, the cross‐effect of pH (3, 7, and 9) and salinity (0, 7, and 35 practical salinity unit, using artificial sea water) on the passive sampling of 21 pharmaceuticals (antiparasitics, beta‐blockers, non‐steroidal anti‐inflammatory drugs, sulfonamides) was tested. The primarily determined parameter was the sampling rate. In addition, the extraction efficiency, partitioning coefficient, and the concentration of the analytes on the sorbent were calculated. Generally, for the non‐steroidal anti‐inflammatory drugs, beta‐blockers, and antiparasitics, the change both in pH and salinity had a negligible impact on the mentioned experimental parameters. In contrast, the extraction of sulfonamides was impacted by both pH and salinity, while lipophilicity was not a decisive parameter.     

Alteration of the physicochemical properties of catalysts based on aqueous solutions of Mo-V-P heteropoly acids in redox processes

Selective catalytic oxidation of various organic substrates with O₂ in the presence of aqueous solutions of Mo-V-P heteropoly acids (HPA) is carried out via two stages in separate reactors. In stage (1), a substrate is oxidized into a desired product while HPA is reduced. The reduced form of HPA is oxidized with O₂ in stage (2). A set of the physicochemical properties of the homogeneous catalyst has been found to alter continuously during these redox processes. Using a solution of the modified high-vanadium HPA (H₁₂P₃Mo₁₈V₇O₈₅), we demonstrate that the density, viscosity, and pH of this solution reach their maxima after reaction (1) and attain their minima after reaction (2). On the contrary, the redox potential of the solution is minimum after reaction (1), and maximum after reaction (2). All alterations of the physicochemical properties of the catalyst are found to be completely reversible.