放射性核素在海洋环境吸附体系中的固体浓度效应

通过Ag-110m在海洋沉积物中的静态吸附-解吸实验,系统地研究了放射性核素在海洋环境吸附体系中的固体浓度效应。实验结果表明:Ag-110m在海洋沉积物中的吸附-解吸等温线趋近于线性,且随着固体浓度的升高,等温线呈下降趋势,存在固体浓度效应。解吸等温线比吸附等温线滞后,固体浓度0.1~1.0g·L~(-1)范围内,吸附滞后角(θ)随着固体浓度的增加逐渐增大,不可逆性明显增强,固体浓度改变了吸附体系的不可逆性,符合"亚稳平衡吸附理论"对固体浓度效应产生机制的预测,而固体浓度达到3.0g·L~(-1)后,吸附-解吸等温线几乎重合,体系接近可逆反应。因此对于放射性核素,存在一个区间范围使得吸附体系的不可逆程度随固体浓度的增加而增大,但是超过区间的上、下限值后,体系趋近于可逆反应。应用Freundlich-SCA表面组分活度模型,用活度代替浓度,校正实际与理想吸附体系间的偏离,将不同固体浓度下的吸附-解吸实验数据分别归入同一条吸附等温线和解吸等温线,可以用来预测其他固体浓度下的吸附-解吸平衡状态。     

硅胶的表面硫醇化改性及对水溶液中罗丹明B的固载

运用γ-巯丙基三乙氧基硅烷对硅胶表面硫醇化修饰改性,红外及拉曼光谱分析表明硅胶的表面硫醇化借助硅胶表面羟基与γ-巯丙基二乙氧基硅烷间的化学键联实现。实验条件下改性硅胶对水体罗丹明B的吸附性能明显提升,改性硅胶表面罗丹明B的吸附动力学符合准二级动力学模型,吸附等温线服从Langmuir等温线规律,由等温吸附计算得到的热力学函数变化表明吸附系自发、放热过程。吸附动力学、热力学及光谱表征均表明改性硅胶上罗丹明B的吸附主要为其在改性硅胶表面借助电价和共价键联的化学吸附。     

表面活性剂对脂肪酶活性和选择性的影响

考察了几种表面活性剂对lipaseOF粗酶和纯化酶催化拆分酮基布洛芬的影响。除吐温-80,吐温-60和壬基酚聚氧乙烯醚外,大部分表面活性剂对酶活性有抑制作用,其中只有吐温-80能显著提高酶的立体选择性。酶的活性和选择性与表面活性剂浓度有关。在表面活性剂浓度为最佳(20mg/mL吐温-80或30mg/mL壬基酚聚氧乙烯醚)时lipaseOF粗酶的活性可分别提高13和15倍。加入80mg/mL吐温-80,粗酶和纯化酶的对映体选择率(E值)分别由1.1和8.0增至6.7和>100。     

硅胶的表面硫醇化改性及对水溶液中罗丹明B的固载（英文）

运用γ-巯丙基三乙氧基硅烷对硅胶表面硫醇化修饰改性,红外及拉曼光谱分析表明硅胶的表面硫醇化借助硅胶表面羟基与γ-巯丙基二乙氧基硅烷间的化学键联实现。实验条件下改性硅胶对水体罗丹明B的吸附性能明显提升,改性硅胶表面罗丹明B的吸附动力学符合准二级动力学模型,吸附等温线服从Langmuir等温线规律,由等温吸附计算得到的热力学函数变化表明吸附系自发、放热过程。吸附动力学、热力学及光谱表征均表明改性硅胶上罗丹明B的吸附主要为其在改性硅胶表面借助电价和共价键联的化学吸附。     

表面活性剂对脂肪酶活性和选择性的影响

考察了几种表面活性剂对lipaseOF粗酶和纯化酶催化拆分酮基布洛芬的影响。除吐温-80,吐温-60和壬基酚聚氧乙烯醚外,大部分表面活性剂对酶活性有抑制作用,其中只有吐温-80能显著提高酶的立体选择性。酶的活性和选择性与表面活性剂浓度有关。在表面活性剂浓度为最佳(20mg/mL吐温-80或30mg/mL壬基酚聚氧乙烯醚)时lipaseOF粗酶的活性可分别提高13和15倍。加入80mg/mL吐温-80,粗酶和纯化酶的对映体选择率(E值)分别由1.1和8.0增至6.7和>100。     

国产硅藻土吸附尿激酶机理的研究

在常温下, 尿激酶在浙江土和吉林土表面的吸附等温线分别为V型和II型; 焙烧后两者皆转为III型。吸附等温线类型与硅藻土表面结构、孔结构、表面ζ电位有关。在400℃焙烧的硅藻土等电点值最低, 吸附量最大; 改性后, 吸附量也发生改变。本文还测定了尿激酶在硅藻土表面的吸附形态, 其吸附等温线方程符合0/(1-0)=(Kc)^1/β, 并讨论了平衡常数K和尿激酶吸附功能链段数β随温度的变化。     

吐温-60对钢在Cl2CHCOOH溶液中的缓蚀性能

通过失重法、动电位极化曲线和电化学阻抗谱(EIS)研究了非离子表面活性剂吐温-60在0.10 mol·L^-1二氯乙酸(Cl₂CHCOOH)溶液中对冷轧钢的缓蚀性能，并且采用扫描电子显微镜(SEM)、原子力显微镜(AFM)和接触角测试对冷轧钢表面的微观形貌和亲水/疏水性进行了表征分析。结果表明：20℃时100 mg·L^-1吐温-60的缓蚀率可达89.6%,6～48 h内缓蚀效果稳定；20～50℃时吐温-60在冷轧钢表面的吸附符合Langmuir吸附等温式，标准吸附Gibbs自由能为-42.92～-47.41 kJ·mol^-1,吸附过程中伴随着熵增加。动电位极化曲线表明吐温-60为“几何覆盖效应”的混合抑制型缓蚀剂；随着吐温-60浓度的增大，Nyquist图的容抗弧半径增大，电荷转移电阻增大，而界面双电层电容值下降。SEM和AFM的微观表面形貌进一步证实了吐温-60能有效减缓钢表面的腐蚀程度；缓蚀后钢表面接触角增大，表面疏水性增强，可有效屏蔽酸介质对钢表面的腐蚀。     

最大气泡压力法测表面张力等温线教学实验的试剂选择*

回顾了国内最大气泡压力法测定溶液表面张力等温线教学实验历年的设计与改进。比较了乙酸、丙酸、正丁酸、2-甲基丁酸、3-甲基丁酸、正戊酸、正己酸、甲醇、丙醇、异丙醇、正丁醇、异丁醇、乙二醇、1, 2-丙二醇、吐温20、吐温80、十二烷基硫酸钠等17种常用试剂在25 ℃下的表面张力等温线,及部分试剂在15,20,25,35 ℃下的表面张力等温线,指出正丁醇、异丙醇、丙醇是较为理想的教学实验备选试剂。     

硅烷化活性炭的吸附性质

本工作测定了25℃和35℃时硅烷化活性炭自水溶液中吸附苯甲酸和苯甲醛的等温线;计算了吸附过程的ΔGⅲ,ΔHⅲ和ΔSⅲ;用Hill-deBoer方程处理了实验结果。所得结果表明:(1)随硅烷化时间延长,苯甲酸和苯甲醛的吸附量(mol.m^-^2)明显增加;-ΔGⅲ和-ΔHⅲ略有升高,ΔSⅲ为正值;(2)吸附分子之间的相互作用很弱,吸附分子与活性炭表面间的作用随硅烷化程度增加而加大;(3)芳香化合物可能是以苯环吸附在炭表面上的。     

硅胶的表面硫醇化改性及对水溶液中罗丹明B的固载

运用γ-巯丙基三乙氧基硅烷对硅胶表面硫醇化修饰改性, 红外及拉曼光谱分析表明硅胶的表面硫醇化借助硅胶表面羟基与γ-巯丙基二乙氧基硅烷间的化学键联实现。实验条件下改性硅胶对水体罗丹明B的吸附性能明显提升, 改性硅胶表面罗丹明B的吸附动力学符合准二级动力学模型, 吸附等温线服从Langmuir等温线规律, 由等温吸附计算得到的热力学函数变化表明吸附系自发、放热过程。吸附动力学、热力学及光谱表征均表明改性硅胶上罗丹明B的吸附主要为其在改性硅胶表面借助电价和共价键联的化学吸附。     

Inhibition of cold rolled steel corrosion by Tween-20 in sulfuric acid: weight loss, electrochemical and AFM approaches

The inhibiting action of a nonionic surfactant of Tween-20 on the corrosion of cold rolled steel (CRS) in 0.5-7.0 M sulfuric acid (H(2)SO(4)) was studied by weight loss and potentiodynamic polarization methods. Atomic force microscope (AFM) provided the surface conditions. The results show that inhibition efficiency increases with the inhibitor concentration, while it decreases with the sulfuric acid concentration. The adsorption of inhibitor on the cold rolled steel surface obeys the Langmuir adsorption isotherm equation. Effect of immersion time was studied and discussed. The effect of temperature on the corrosion behavior of cold rolled steel was also studied at four temperatures ranging from 30 to 60 degrees C, the thermodynamic parameters such as adsorption heat, adsorption free energy, and adsorption entropy were calculated. The results revealed that the adsorption was physisorption mechanism. A kinetic study of cold rolled steel in uninhibited and inhibited acid was also discussed. The kinetic parameters such as apparent activation energy, pre-exponential factor, rate constant, and reaction constant were calculated for the reactions of corrosion. The inhibition effect is satisfactorily explained by both thermodynamic and kinetic models. Polarization curves show that Tween-20 is a cathodic-type inhibitor in sulfuric acid. The results obtained from weight loss and potentiodynamic polarization are in good agreement, and the Tween-20 inhibition action could also be evidenced by surface AFM images.     

Tween-20与牛血清白蛋白的相互作用

通过表面张力和等温滴定量热方法，研究了非离子表面活性剂Tween-20与牛血清白蛋白(BSA)的相互作用. 结果表明，BSA与Tween-20的相互作用较弱，当Tween-20浓度增大时，能将吸附于表面上的BSA分子取代. BSA/Tween-20混合体系的性质随温度的变化趋势与单一非离子型表面活性剂相似. BSA浓度在3.7×10^-5～11.1×10^-5 kg•L^-1范围内，Tween-20的cmc不随BSA浓度的变化而变化. 当Tween-20的含量一定时，Tween-20与BSA相互作用过程的热效应也与BSA 的浓度无关. BSA/Tween-20混合体系的热力学参数表明， BSA的存在使Tween-20的cmc减小，体系的熵变增大.     

Determination of trace glucose and forecast of human diseases by affinity adsorption solid substrate-room temperature phosphorimetry based on triticum vulgaris lectin labeled with dendrimers-porphyrin dual luminescence molecule

In this paper, 3.5-generation polyamidoamine dendrimers (3.5G-D)-porphyrin (P) dual luminescence molecule (3.5G-D-P) was developed as a new phosphorescence-labeling reagent. Meanwhile, the room temperature phosphorescence (RTP) characteristics of 3.5G-D-P and its product of labeling triticum vulgaris lectin (WGA) on the surface of polyamide membrane (PAM) were studied. Results showed that in the presence of heavy atom perturber LiAc, 3.5G-D and P of 3.5G-D-P molecule could emit strong and stable RTP on the PAM. And the Tween-80 would spike thoroughly the phosphorescence signal of 3.5G-D and P; moreover, specific affinity absorption (AA) reaction between the products (Tween-80-3.5G-D-P-WGA) of WGA labeled with Tween-80-3.5G-D-P and glucose (G) was carried out. The products of the AA reaction could keep good RTP characteristics of 3.5G-D and P dual luminescence molecule, and the DeltaI(p) was linear correlation to the content of G. According to the facts above, a new method of affinity adsorption solid substrate-room temperature phosphorimetry (AA-SS-RTP) for the determination of trace G was established, basing on WGA labeled with Tween-80-3.5G-D-P dual luminescence molecule. The detection limit of this method was 0.13fgspot(-1) (1.7x10(-12)moll(-1), 3.5G-D) and 0.14fgspot(-1) (2.2x10(-12)moll(-1), P). Determination of G in human serum using excitation/emission wavelength of either 3.5G-D or P, the result was coincided with enzyme-linked immunosorbent assay (ELISA). Not only the sensitivity and accuracy of this method were higher, but also the flexibility of AA-SS-RTP was obviously improved and the applicability was wider.     

Imitation of artificial membrane system via mobile phases with Tween-80 and cholic acid in biopartitioning micellar chromatography

The chromatographic behaviour of compounds of biomedical significance was studied using micellar mobile phases modified with polyoxyethylene (20) sorbitan monooleate (Tween-80). The influence of the surfactant within the 0.75-4% concentration range on the retention factor of model compounds was investigated. The biological surfactant cholic acid was introduced into the mobile phases in order to approach to the structure of natural membranes, viz. erythrocyte and cytoplasmatic membranes. It was found that curves of dependence of retention factor vs concentration of Tween-80 in the absence and presence of cholic acid in the mobile phase considerably diverge with one another, especially in the 2-3% concentration range of Tween-80 using C18-type support. Increasing the concentration of Tween-80 resulted in the increase of retention factors using phenyl-coated stationary phase.     

Micellization and surface properties of aqueous solutions of binary mixtures of tween-80 and bromide cetyltrimethylammonium

The physicochemical properties of solutions of mixtures of cationic (cetiltrimethylammonum bromide) and nonionic (polyoxyethylene (20) sorbitan monooleate) surfactant, i.e., Tween-80, have been studied. The critical concentration of micellization, adsorption at the interface of a mixture of surfactants solution/air, and the minimum area occupied by a surfactant molecule have been determined. It was shown that, in the whole region of ratios between surfactants, sinergic effects are observed for both micellization and for the process of adsorption at the interface of a mixture of surfactants solution/air. The results obtained have been analyzed according to the regular solution theory (RST).     

Acid-base equilibrium of anionic dyes partially bound to micelles of nonionic surfactants

The acid-base equilibria of the sulfonephthalein dyes, namely, bromothymol blue, thymol blue, and cresol red, in aqueous nonionic micellar solutions of Triton X-100, Tween-20, Tween-40, Tween-60, and Tween-80 have been investigated. The equilibrium constants of the partition of the dyes between micellar and aqueous pseudophases have been determined spectrophotometrically at fixed pH. The K(ass) increased with the surfactants in the order Tween-80相似文献   

Effects of the physicochemical properties of the emulsion formulation on the bioavailability of ethyl 2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)phenyl]propionate in rats

The effect of the physicochemical properties of the emulsion formulation on the absorption of ethyl 2-chloro-3-[4-(2-methyl-2-phenylpropyloxy)phenyl]propionate (AL-294) in rats and dogs was studied. When emulsions of different particle sizes were administered to rats, the higher the ratio of Tween-80 to the drug was, the smaller was the particle size and the higher was the absorption. When the emulsions of similar particle size (2 microns) with different Tween-80 ratios were administered to rats, no significant difference was observed in the extent of absorption. The absorption of AL-294 was correlated with the dissolution rate from the oil phase to the aqueous phase but not correlated with the amount of AL-294 solubilized by Tween-80. These results indicate that the absorption of AL-294 from emulsions depends mainly on the particle size in the gastro-intestinal fluid and that Tween-80 serves only to reduce the particle size in the emulsion.     

吐温表面活性剂囊泡对姜黄素的包载作用

本文研究了烷基链不饱和度对吐温表面活性剂囊泡包载姜黄素的影响。相比吐温-80囊泡,吐温-60囊泡的包载使姜黄素表现出更大的紫外吸收和荧光发射强度、缔合常数和DPPH自由基清除能力。核磁共振氢谱结果表明姜黄素缔合于吐温-60囊泡双分子层中的亲水头基附近,而且姜黄素的酚羟基与吐温-60的酯基产生氢键作用。在吐温-80囊泡中,双键会使吐温-80烷基链产生弯曲或折叠,导致双分子层排列更加松散、极性更高。因此,姜黄素除了与吐温-80的酯基产生氢键作用外,还能与吐温-80烷基链尾部和中部的亚甲基发生作用。     

Effect of surfactants and zeolites on simultaneous saccharification and fermentation of steam-exploded poplar biomass to ethanol

In this work, the effect of the addition of different concentrations of Tween-80 and three different zeolite-like products on enzymatic hydrolysis, ethanol fermentation, and simultaneous saccharification and fermentation (SSF) process has been investigated. The ability of these products to enhance the effectiveness of the SSF process to ethanol of steam-exploded poplar biomass using the thermotolerant strainKluyveromyces marxianus EMS-26 has been tested. Tween-80 (0.4 g/L) increased enzymatic hydrolysis yield by 20% when compared to results obtained in hydrolysis in absence of the additive. Zeolite-like products (ZESEP-56 and ZECER-56) (2.5 g/L) improved rates of conversion and ethanol yields in the fermentation of liquid fraction recovered from steam-exploded poplar. The periods required for the completion of fermentation were approx 10 h in the presence of zeolite-like products and 24 h in the absence of additives. The probable mode of action is through lowered levels of inhibitory substances because of adsorption by the additive.     

新体系催化动力学光度法测定痕量亚硝酸根

基于增敏剂吐温 - 80存在下亚硝酸根催化过氧化氢氧化中性红的反应 ,建立了测定痕量亚硝酸根的新催化动力学光度法。方法的灵敏度较常规方法提高了 2 .2倍 ,测定的线性范围为 2～ 1 0 μg/L,检出限为 2 .7× 1 0 - 10 g/m L。已用于测定水样中 NO2 - 的含量