Surface tension studies of lauryl sulfobetaine - β-cyclodextrin and dodecyltrimethylammonium bromide - β-cyclodextrin inclusion complexes in aqueous solution

1999 ◽  
Vol 77 (7) ◽  
pp. 1208-1213 ◽  
Author(s):  
S Göktürk ◽  
M Mahramanlloglu ◽  
M Tunçay
Keyword(s):  
Surface Tension ◽  
Complex Formation ◽  
Inorganic Compounds ◽  
Binding Constants ◽  
Polar Group ◽  
Dodecyltrimethylammonium Bromide ◽  
Adsorption Model ◽  
Langmuir Adsorption ◽  
Polar Groups ◽  
Concentration Curves

β-Cyclodextrin (β-CD) is a cyclic oligosaccaride with an apolar cavity that shows a certain degree of selectivity in binding organic and inorganic compounds. Lauryl sulfobetaine (LSB) and dodecyltrimethylammonium bromide (DTAB), having the same hydrophobic and different polar groups are used in order to compare the influence of the polar group on complex formation with β-CD. The surface tension increased as β-CD is added to premicellar region of amphoteric (LSB) and cationic surfactant (DTAB) solutions. The relation between the surface tension and surfactant concentration can be expressed by the Szyszkowski equation, which combines the Langmuir adsorption model and the Gibbs equation. Binding constants were determined from the effect of added β-CD on the surface tension vs. concentration curves for LSB and DTAB aqueous solutions.Key words: β-cyclodextrin, surfactant, surface tension method, complex formation, binding constant.

scholarly journals A Study on Solubilization of Poorly Soluble Drugs by Cyclodextrins and Micelles: Complexation and Binding Characteristics of Sulfamethoxazole and Trimethoprim

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Sinem Göktürk ◽  
Elif Çalışkan ◽  
R. Yeşim Talman ◽  
Umran Var
Keyword(s):  
Surface Tension ◽  
Complex Formation ◽  
Sodium Dodecyl ◽  
Binding Constants ◽  
Phase Solubility ◽  
Poorly Soluble Drugs ◽  
Binding Characteristics ◽  
Sds Micelles ◽  
Poorly Soluble ◽  
Triton X

The present study is focused on the characterization of solubilization of poorly soluble drugs, that is, sulfamethoxazole (SMX) and trimethoprim (TMP) by cyclodextrins (α-, β-, and γ-CDs) and anionic surfactant sodium dodecyl sulfate (SDS). The phase solubility diagrams drawn from UV spectral measurements are of theALtype and indicate an enhancement of SMX and TMP solubility in the presence of CDs. Complex formation tendency of TMP with CDs followed the order: γ-CD > β-CD > α-C. However, the complex formation constant values, for SMX-CD system yielded the different affinity and follow the order: β-CD > γ-CD > α-CD. With taking into consideration of solubilization capacity of SDS micelles, it has been found that the solubility enhancement of TMP is much higher than that of SMX in the presence of SDS micelles. The binding constants of SMX and TMP obtained from the Benesi-Hildebrand equation are also confirmed by the estimated surface properties of SDS, employing the surface tension measurements. In order to elucidate the solubilization characteristics the surface tension measurements were also performed for nonionic surfactant Triton X-100. Polarity of the microenvironment and probable location of SMX and TMP were also discussed in the presence of various organic solvents.

scholarly journals Self-assembly of sodium dodecylsulfate and dodecyltrimethylammonium bromide mixed surfactants with dyes in aqueous mixtures

2019 ◽  
Vol 6 (3) ◽  
pp. 181979 ◽  
Author(s):  
K. M. Sachin ◽  
Sameer A. Karpe ◽  
Man Singh ◽  
Ajaya Bhattarai
Keyword(s):  
Surface Tension ◽  
Self Assembly ◽  
Sodium Dodecylsulfate ◽  
Critical Micellar Concentration ◽  
Aqueous System ◽  
Mixed Surfactants ◽  
Dodecyltrimethylammonium Bromide ◽  
Aqueous Mixtures ◽  
Krafft Temperature ◽  
Vis Spectroscopy

The micellar property of mixed surfactant systems, cationic (dodecyltrimethylammonium bromide, DTAB) and anionic (sodium dodecylsulfate, SDS) surfactants with variable molar ratios in aqueous system has been reported by using surface tension and conductivity measurements at T = 293.15, 298.15 and 303.15 K. DTAB concentrations are varied from 1.0 × 10 −4 to 3 × 10 −4 mol l −1 in 1.0 × 10 −2 mol l −1 SDS solution while the SDS concentration is varied from 1.0 × 10 −3 to 1.5 × 10 −2 mol l −1 in approximately 5.0 × 10 −3 mol l −1 DTAB, so that such concentrations of DTAB-SDS (DTAB-rich) and SDS-DTAB (SDS-rich) solutions were chosen 3 : 1 ratio. The critical micellar concentration, as well as surface and thermodynamic properties for DTAB-rich and SDS-rich solutions, were evaluated by the surface tension ( γ ) and conductivity ( κ ) methods. The pseudo phase separation model was coupled with the dissociated Margules model for synergism. The Krafft temperature behaviour and optical analysis of mixed surfactants are studied using conductivity and UV–Vis spectroscopy, respectively. The dispersibility and stability of DTAB-rich and SDS-rich solutions with and without dyes (2.5 × 10 −5 mol l −1 of methyl orange and methylene blue) are carried out by using UV–Vis spectroscopy and dynamic light scattering.

scholarly journals Aerosol hygroscopicity at high (99 to 100%) relative humidities

2009 ◽  
Vol 9 (4) ◽  
pp. 15595-15640 ◽  
Author(s):  
C. R. Ruehl ◽  
P. Y. Chuang ◽  
A. Nenes
Keyword(s):  
Surface Tension ◽  
Inorganic Compounds ◽  
Droplet Diameter ◽  
Pure Water ◽  
Sodium Dodecyl ◽  
Bulk Solution ◽  
Active Compounds ◽  
Surface Active ◽  
Surface Active Compounds ◽  
Aerosol Hygroscopicity

Abstract. The hygroscopicity of an aerosol largely determines its influence on climate and, for smaller particles, atmospheric lifetime. While much aerosol hygroscopicity data is available at lower relative humidities (RH) and under cloud formation conditions (RH>100%), relatively little data is available at high RH (99.2 to 99.9%). We measured the size of droplets at high RH that had formed on particles composed of one of seven compounds with dry diameters between 0.1 and 0.5 μm, and calculated the hygroscopicity of these compounds. We use a parameterization of the Kelvin term, in addition to a standard parameterization (κ) of the Raoult term, to express the hygroscopicity of surface-active compounds. For inorganic compounds, hygroscopicity could reliably be predicted using water activity data and assuming a surface tension of pure water. In contrast, most organics exhibited a slight to mild increase in hygroscopicity with droplet diameter. This trend was strongest for sodium dodecyl sulfate (SDS), the most surface-active compound studied. The results suggest that partitioning of surface-active compounds away from the bulk solution, which reduces hygroscopicity, dominates any increases in hygroscopicity due to reduced surface tension. This is opposite to what is typically assumed for soluble surfactants. Furthermore, we saw no evidence that micellization limits SDS activity in micron-sized solution droplets, as observed in macroscopic solutions. These results suggest that while the high-RH hygroscopicity of inorganic compounds can be reliably predicted using readily available data, surface-activity parameters obtained from macroscopic solutions with organic solutes may be inappropriate for calculations of the hygroscopicity of micron-sized droplets.

scholarly journals The Effect of Deposition Time on the Surface Coverage of Sublimation Deposited Solid-Phase Glycine and Proline Molecules Measured by Scanning Tunneling Microscopy

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2962
Author(s):  
Young-Sang Youn
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Room Temperature ◽  
Deposition Time ◽  
Surface Coverage ◽  
Solid Phase ◽  
Scanning Tunneling ◽  
Adsorption Model ◽  
Tunneling Microscopy ◽  
Langmuir Adsorption ◽  
Stm Images

The effect of deposition time on the surface coverage of sublimation deposited solid-phase glycine and proline molecules onto a Ge(100) surface was studied at room temperature using scanning tunneling microscopy (STM). The STM images obtained at various coverages of glycine and proline adsorbed on the Ge(100) surface showed that (i) the adsorption rate for both molecules gradually decreased with increasing deposition time, obeying the Langmuir adsorption model, and (ii) the coverage of glycine on the Ge(100) surface is higher than that of proline under the same deposition conditions, which may be due to the differences in their molecular weight or molecular sticking probability.

scholarly journals Determination of the absolute CH4 adsorption using simplified local density theory and comparison with the modified Langmuir adsorption model

RSC Advances ◽  
2018 ◽  
Vol 8 (72) ◽  
pp. 41509-41516
Author(s):  
Yeyu Zhang ◽  
Shaonan Zhang ◽  
Zhicheng Wang ◽  
Hucheng Deng ◽  
Minghui Qi ◽  
...  
Keyword(s):  
Shale Gas ◽  
Local Density ◽  
Gas Storage ◽  
Adsorption Model ◽  
Gas Reservoirs ◽  
Methane Recovery ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Ch4 Adsorption

Accurately determining the adsorbed amount of CH4 on shale is significant for understanding the mechanisms of shale gas storage and shale methane recovery from shale gas reservoirs.

Kinetic and spectrophotometric studies of binding of iron(III) by glutathione

1976 ◽  
Vol 54 (20) ◽  
pp. 3192-3199 ◽  
Author(s):  
Tahir R. Khan ◽  
Cooper H. Langford
Keyword(s):  
Complex Formation ◽  
Kinetic Method ◽  
Binding Constants ◽  
Chelating Agent ◽  
Formation Reaction ◽  
Spectrophotometric Data ◽  
Natural Water Chemistry ◽  
Kinetics Of ◽  
Sulfur Containing

In this report, determination of unbound aquo iron species is accomplished by a kinetic method involving reaction with sulfosalicylic acid (SSA) on a time scale which is very short with respect to reaction of SSA with the glutathione complexes of iron. The data are used to calculate conditional binding constants for Fe(III) to glutathione. Binding constants in 0.1 M ionic strength media were obtained between pH 1 and 2.4 by the kinetic method, and near pH = 3 by spectrophotometry and by examination of the ratio of rate of complex formation and dissociation. The conditional binding 'constant' between pH 1 and 3 is represented as pK = −1.96 – 0.50pH. This is consistent with the importance of reactions involving only very limited proton release. Spectrophotometric data show that the —OH group on Fe(OH)2+ is lost on glutathione complexing. Kinetics of the complex formation reaction between aquo iron(III) species and glutathione are slower than rates of reaction of iron(III) with simple ligands.The glutathione system is regarded as a model system important to natural water chemistry because it is a widely distributed biological sulfur-containing chelating agent.

scholarly journals Sodium hydroxide modified rice husk for enhanced removal of copper ions

2018 ◽  
Vol 78 (7) ◽  
pp. 1615-1623 ◽  
Author(s):  
N. Priyantha ◽  
H. K. W. Sandamali ◽  
T. P. K. Kulasooriya
Keyword(s):  
Heavy Metal ◽  
Adsorption Capacity ◽  
Rice Husk ◽  
Copper Ions ◽  
Maximum Adsorption Capacity ◽  
Adsorption Model ◽  
Natural Form ◽  
Langmuir Adsorption ◽  
Pseudo Second Order ◽  
Heavy Metal Adsorbent

Abstract Although rice husk (RH) is a readily available, natural, heavy metal adsorbent, adsorption capacity in its natural form is insufficient for certain heavy metal ions. In this context, the study is based on enhancement of the adsorption capacity of RH for Cu(II). NaOH modified rice husk (SRH) shows higher extent of removal for Cu(II) ions than that of heated rice husk (HRH) and HNO3 modified rice husk (NRH). The extent of removal of SRH is increased with the concentration of NaOH, and the optimum NaOH concentration is 0.2 mol dm−3, used to modify rice husk for further studies. The surface area of SRH is 215 m2 g−1, which is twice as much as that of HRH according to previous studies. The sorption of Cu(II) on SRH obeys the Langmuir adsorption model, leading to the maximum adsorption capacity of 1.19 × 104 mg kg−1. Kinetics studies show that the interaction of Cu(II) with SRH obeys pseudo second order kinetics. The X-ray fluorescence spectroscopy confirms the adsorption of Cu(II) on SRH, while desorption studies confirm that Cu(II) adsorbed on SRH does not leach it back to water under normal conditions.

Inclusion complexation involving sugar-containing species: β-cyclodextrin and sugar surfactants

2004 ◽  
Vol 82 (1) ◽  
pp. 45-49 ◽  
Author(s):  
Vincent C Reinsborough ◽  
Vanessa C Stephenson
Keyword(s):  
Surface Tension ◽  
Critical Micelle Concentration ◽  
Inclusion Complex ◽  
Computer Modeling ◽  
Inclusion Complexation ◽  
Binding Constants ◽  
Guest Molecules ◽  
Sugar Moiety ◽  
G 12 ◽  
Concentration Surface

Surface tension, proton NMR, and computer modeling studies were undertaken in nonionic alkylpolyglycoside (APG) solutions containing β-cyclodextrin (β-CD) with a view to characterize the inclusion complexes formed and to determine if the sugar entities of the host and guest molecules played a significant role in the process. The APGs investigated were four glucopyranosides (octyl G8, decyl G10, dodecyl G12, tetradecyl G14) and two maltosides (decyl M10, dodecyl M12). Critical micelle concentrations (CMC) were obtained in the surfactant–β-CD systems, which in all cases increased with increasing β-CD concentration. The 1:1 APG–β-CD inclusion complex was principally formed with binding constants of 425 (mol L–1)–1 for the G12 complex, 340 (mol L–1)–1 for the G10 complex, and 125 (mol L–1)–1 for the M12 complex. The preferred configuration of the G-12–β-CD complex has the surfactant tail coiled in the CD cavity with the surfactant sugar moiety sealing off the narrower opening of the CD torus.Key words: alkylpolyglycoside, β-cyclodextrin, NMR, critical micelle concentration, surface tension.

Investigation of Ultrasonic Effects in Cotton Dyeing Processing

2013 ◽  
Vol 787 ◽  
pp. 138-142 ◽  
Author(s):  
De Shuai Sun ◽  
Long Fang ◽  
Tao Liu
Keyword(s):  
Cotton Fiber ◽  
Ultrasound Irradiation ◽  
Cotton Fabrics ◽  
Dye Uptake ◽  
Adsorption Model ◽  
Langmuir Adsorption ◽  
Langmuir Adsorption Model ◽  
Dyeing Process ◽  
Direct Dye ◽  
Ultrasound Dyeing

Ultrasound can promote the dye-uptake in the dyeing process. The effects of ultrasound on the fiber, dye and dyeing system were investigated by dyeing cotton fabrics with a direct dye. The dye exhaustion exceeded 80% in 30 minutes with the assistant of ultrasound. Langmuir adsorption model could descript the ultrasound dyeing process of direct dye. The area of fiber accessibility of cotton fiber increased 1.68 times under the action of ultrasound. The absorbance of direct dye solution increased remarkably in the first 10 minutes of ultrasound irradiation. Ultrasound accelerated the diffusion of dye on cotton fiber, and then the diffusion coefficient increased 46 times

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