scholarly journals Interactions of short chain phenylalkanoic acids within ionic surfactant micelles in aqueous media

2012 ◽  
Vol 77 (2) ◽  
pp. 201-210 ◽  
Author(s):  
Kashif Naeem ◽  
Syed Shah ◽  
Bushra Naseem ◽  
Syed Shah
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Alkyl Chain ◽  
Aqueous Media ◽  
Sodium Dodecyl ◽  
Standard Free Energy ◽  
Bulk Water ◽  
Uv Spectra ◽  
Ionic Surfactant ◽  
Standard Free Energy Change ◽  
Surfactant Micelles

% SDS KR nema Solubilization and interactions of phenylalkanoic acids induced by cationic surfactant, cetyltrimethylammonium bromide (CTAB) and an anionic surfactant, sodium dodecyl sulfate (SDS) was investigated spectrophotometrically at 25.0?C. The UV spectra of the additives (acids) were measured with and without surfactant above and below critical micelle concentration (cmc) of the surfactant. The presence of alkyl chain in phenylalkanoic acids is responsible for hydrophobic interaction resulting in shift of the spectra towards longer wavelength (red shift). The value of partition coefficient (Kx) between the bulk water and surfactant micelles and in turn standard free energy change of solubilization (?Gp?) were also estimated by measuring the differential absorbance (?A) of the additives in micellar solutions.

Interaction of Porphyrins with Cetyltrimethylammonium Bromide Micelles in Methylene Chloride

1998 ◽  
Vol 02 (04) ◽  
pp. 345-351 ◽  
Author(s):  
NILKAMAL BAG ◽  
ARUNA DHATHATHREYAN ◽  
ASIT BARAN MANDAL ◽  
TIRUMALACHARI RAMASAMI
Keyword(s):  
Free Energy ◽  
Cetyltrimethylammonium Bromide ◽  
Methylene Chloride ◽  
Aggregation Number ◽  
Film Formation ◽  
Cetylpyridinium Chloride ◽  
Standard Free Energy ◽  
Micelle Formation ◽  
Standard Free Energy Change ◽  
Biphasic Model

The formation of micelles of cetyltrimethylammonium bromide (CTAB) in CH 2 Cl 2 solution has been reported for the first time. The critical micelle concentrations (cmc) of CTAB in CH 2 Cl 2 solution were determined using conductivity and fluorescence techniques in both the absence and presence of 1,3,5,7-tetramethyl-2,4,6,8-tetra(2,4,6-triisopropylphenyl)porphyrin (TMTIP). The cmc values obtained by conductivity and fluorescence methods were found to be 75 and 78 mM, respectively. The aggregation numbers (N) of CTAB and porphyrin–CTAB in CH 2 Cl 2 solution were determined using pyrene and N-cetylpyridinium chloride (CPC) as the fluoroprobe and quencher, respectively. The N of CTAB in CH 2 Cl 2 solution was also determined using the porphyrin (in lieu of pyrene) as the fluoroprobe and CPC as the quencher. The N of CTAB obtained by these probes was found to be 134 ± 3 and 140 ± 5, respectively. This suggests that the porphyrin could be used as an excellent fluoroprobe for determination of the aggregation number of CTAB micelles. The results of both cmc and aggregation number suggest that the micelle formation of CTAB in CH 2 Cl 2 solution is favored in the presence of the porphyrin. The standard free energy change for micelle formation of CTAB in CH 2 Cl 2 solution was calculated using a biphasic model. The standard free energy transfer [Formula: see text] of CTAB micelles from CH 2 Cl 2 to porphyrin environment has been found to be −1.0 kJ mol−1 at 25 °C, suggesting that the above transfer is difficult. However, the reverse situation, i.e. binding of the porphyrin to CTAB micelles, is more probable. The Langmuir–Blodgett (LB) film formation of the porphyrin and metalloporphyrins ( Fe , Co , Cu , Zn ) has also been studied and the UV-vis spectra of these films have been analyzed.

Succinyl Coenzyme A Synthetase of Pig Heart: Studies of the Subunit Structure and of Phosphoenzyme Formation

1972 ◽  
Vol 50 (7) ◽  
pp. 719-724 ◽  
Author(s):  
E. R. Brownie ◽  
W. A. Bridger
Keyword(s):  
Coenzyme A ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Standard Free Energy ◽  
Subunit Structure ◽  
Standard Free Energy Change ◽  
Molecular Weights ◽  
Similarities And Differences ◽  
Bacterial Sources ◽  
Succinyl Coenzyme A Synthetase

Succinyl coenzyme A synthetase from pig heart (molecular weight approximately 75 000) gives rise to two species of subunits when subjected to polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The molecular weights of the constituent subunits are estimated to be about 42 500 and 34 500, suggesting that the enzyme is a dimer. The presence of saturating concentrations of guanosine 5′-triphosphate (GTP) results in the formation of one phosphohistidine residue per molecule of enzyme; the site of phosphorylation is in the smaller subunit. The standard free energy change for phosphorylation of the enzyme by GTP is approximately −400 cal/mol. The results point to both interesting similarities and differences in succinyl-CoA synthetases isolated from mammalian and bacterial sources.

Concentrate of surfactant-based draw solutions in forward osmosis by ultrafiltration and nanofiltration

2015 ◽  
Vol 15 (5) ◽  
pp. 1133-1139
Author(s):  
Hau Thi Nguyen ◽  
Nguyen Cong Nguyen ◽  
Shiao-Shing Chen ◽  
Shu-Ying Wu
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Sodium Dodecyl ◽  
Forward Osmosis ◽  
Ionic Surfactant ◽  
Solute Retention ◽  
Draw Solution ◽  
Molecular Weight Cutoff ◽  
Overall Performance ◽  
Uf Membranes ◽  
First Time

The exploration of coupling surfactants with highly charged phosphate as novel draw solutions for forward osmosis (FO) to minimize salt leakage and enhance draw solute recovery at low energy is presented for the first time. In this work, anionic (sodium dodecyl sulfate (SDS)), cationic (cetyltrimethylammonium bromide) and non-ionic (polyethylene glycol tert-octylphenyl ether, TX-100) surfactants were used to couple with Na3PO4 for enlarging draw solution particle size that could improve the solute retention. Three kinds of nanofiltration (NF) membranes (HL, DL and TS80 with molecular weight cutoff (MWCO) of 100–500) and three kinds of ultrafiltration (UF) membranes (GE, GH and GK with MWCO of 1,000–3,000) were used to evaluate the draw solution recovery. The formed second layer, micelles, MWCO and charged valent were determined to be the dominant mechanisms for diluted draw solution recovery. The results show that coupling non-ionic surfactant with 0.02 M Na3PO4 can be regenerated with recoveries as high as 60% and 96% when using UF-GE and NF-TS80, respectively. The overall performance demonstrates that coupling surfactant with highly charged phosphate is promising as draw solutes for application to FO.

scholarly journals CONTINUUM ELECTROSTATICS INVESTIGATION OF IONIC MICELLES USING ATOMISTIC MODELS

2021 ◽  
Vol 87 (6) ◽  
pp. 55-69
Author(s):  
Vladimir Farafonov ◽  
Alexander Lebed ◽  
Nikolay Mchedlov-Petrossyan
Keyword(s):  
Electrostatic Potential ◽  
Sodium Dodecyl ◽  
Theoretical Models ◽  
Ionic Surfactant ◽  
Surfactant Micelle ◽  
Surfactant Micelles ◽  
Atomistic Models ◽  
Ionic Micelles ◽  
Poisson Boltzmann ◽  
Poisson Boltzmann Equation

The key parameter related to the structure of the electric double layer of ionic surfactant micelles – electrostatic potential – is considered. A brief overview of experimental methods and theoretical models for estimating electrostatic potential- is given. The calculating method for the electrostatic potential based on a numerical solution of the Poisson-Boltzmann equation using an atomistic model of anionic surfactant micelle - is proposed. The parameters necessary for the construction of atomistic models - are obtained from molecular dynamic modeling.  The electrostatic potentials for the micelles of sodium dodecyl sulfate and cetyltrimethylammonium bromide at different ionic strengths - were calculated by this method. The results are discussed in comparison with the values calculated in the simplified model, the Ohshima – Healy – White equation.

scholarly journals Inhibition of Escherichia coli O157:H7 and Salmonella enterica Isolates on Spinach Leaf Surfaces Using Eugenol-Loaded Surfactant Micelles

Foods ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 575
Author(s):  
Songsirin Ruengvisesh ◽  
Chris R. Kerth ◽  
T. Matthew Taylor
Keyword(s):  
Escherichia Coli ◽  
Salmonella Enterica ◽  
Limit Of Detection ◽  
Sodium Dodecyl ◽  
Microbial Pathogens ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
Surfactant Micelles ◽  
Leaf Surfaces ◽  
Spinach Leaf

Spinach and other leafy green vegetables have been linked to foodborne disease outbreaks of Escherichia coli O157:H7 and Salmonella enterica around the globe. In this study, the antimicrobial activities of surfactant micelles formed from the anionic surfactant sodium dodecyl sulfate (SDS), SDS micelle-loaded eugenol (1.0% eugenol), 1.0% free eugenol, 200 ppm free chlorine, and sterile water were tested against the human pathogens E. coli O157:H7 and Salmonella Saintpaul, and naturally occurring microorganisms, on spinach leaf surfaces during storage at 5 °C over 10 days. Spinach samples were immersed in antimicrobial treatment solution for 2.0 min at 25 °C, after which treatment solutions were drained off and samples were either subjected to analysis or prepared for refrigerated storage. Whereas empty SDS micelles produced moderate reductions in counts of both pathogens (2.1–3.2 log10 CFU/cm2), free and micelle-entrapped eugenol treatments reduced pathogens by >5.0 log10 CFU/cm2 to below the limit of detection (<0.5 log10 CFU/cm2). Micelle-loaded eugenol produced the greatest numerical reductions in naturally contaminating aerobic bacteria, Enterobacteriaceae, and fungi, though these reductions did not differ statistically from reductions achieved by un-encapsulated eugenol and 200 ppm chlorine. Micelles-loaded eugenol could be used as a novel antimicrobial technology to decontaminate fresh spinach from microbial pathogens.

scholarly journals The Removal of Methylene Blue Dye from Aqueous Solutions Using Activated and Non-Activated Bentonites

2003 ◽  
Vol 21 (5) ◽  
pp. 451-462 ◽  
Author(s):  
Sameer Al-Asheh ◽  
Fawzi Banat ◽  
Leena Abu-Aitah
Keyword(s):  
Methylene Blue ◽  
Ph Value ◽  
Sodium Dodecyl ◽  
Freundlich Isotherm ◽  
Blue Dye ◽  
Batch Adsorption ◽  
Ionic Surfactant ◽  
Methylene Blue Dye ◽  
X Ray Diffraction ◽  
Initial Ph

An improvement in the adsorption capacity of naturally available bentonite towards water pollutants such as Methylene Blue dye (MBD) is certainly needed. For this purpose, sodium bentonite was activated by two methods: (1) treatment with sodium dodecyl sulphate (SDS) as an ionic surfactant and (2) thermal treatment in an oven operated at 850°C. Batch adsorption tests were carried out on removing MBD from aqueous solution using the above-mentioned bentonites. It was found that the effectiveness of bentonites towards MBD removal was in the following order: thermal-bentonite > SDS-bentonite > natural bentonite. X-Ray diffraction analysis showed that an increase in the microscopic bentonite platelets on treatment with SDS was the reason behind the higher uptake of MBD. An increase in sorbent concentration or initial pH value of the solutions resulted in a greater removal of MBD from the solution. An increase in temperature led to an increase in MBD uptake by the bentonites studied in this work. The Freundlich isotherm model was employed and found to represent the experimental data well.

scholarly journals Analysis of Some Biogenic Amines by Micellar Liquid Chromatography

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Irena Malinowska ◽  
Katarzyna E. Stępnik
Keyword(s):  
Liquid Chromatography ◽  
Sodium Dodecyl Sulfate ◽  
Biogenic Amines ◽  
Physicochemical Parameters ◽  
Mobile Phase ◽  
Sodium Dodecyl ◽  
Micellar Liquid Chromatography ◽  
Ionic Surfactant ◽  
Mobile Phases ◽  
Dodecyl Sulfate

Micellar liquid chromatography (MLC) with the use of high performance liquid chromatography (HPLC) was used to determine some physicochemical parameters of six biogenic amines: adrenaline, dopamine, octopamine, histamine, 2-phenylethylamine, and tyramine. In this paper, an influence of surfactant’s concentration and pH of the micellar mobile phase on the retention of the tested substances was examined. To determine the influence of surfactant’s concentration on the retention of the tested amines, buffered solutions (at pH 7.4) of ionic surfactant—sodium dodecyl sulfate SDS (at different concentrations) with acetonitrile as an organic modifier (0.8/0.2 v/v) were used as the micellar mobile phases. To determine the influence of pH of the micellar mobile phase on the retention, mobile phases contained buffered solutions (at different pH values) of sodium dodecyl sulfate SDS (at 0.1 M) with acetonitrile (0.8/0.2 v/v). The inverse of value of retention factor () versus concentration of micelles () relationships were examined. Other physicochemical parameters of solutes such as an association constant analyte—micelle ()—and partition coefficient of analyte between stationary phase and water (hydrophobicity descriptor) () were determined by the use of Foley’s equation.

The Equilibrium and the Determination of D00 (H—CN)

1975 ◽  
Vol 53 (16) ◽  
pp. 2365-2370 ◽  
Author(s):  
Don Betowski ◽  
Gervase Mackay ◽  
John Payzant ◽  
Diethard Bohme
Keyword(s):  
Free Energy ◽  
Standard Enthalpy ◽  
Transfer Reaction ◽  
Standard Free Energy ◽  
Proton Transfer Reaction ◽  
Enthalpy Change ◽  
Standard Free Energy Change ◽  
Flowing Afterglow ◽  
Standard Enthalpy Change

The rate constants and equilibrium constant for the proton transfer reaction [Formula: see text] have been measured at 296 ± 2 K using the flowing afterglow technique: kforward = (2.9 ± 0.6) × 10−9 cm3molecule−1s−1, kreverse = (1.8 ± 0.4) × 10−10 cm3 molecule1 s−1, and K = 16 ± 2. The measured value of K corresponds to a standard free energy change, ΔG296°, of −1.6 ± 0.1 kcal mol−1 which provides values for the standard enthalpy change, ΔH298°= −1.0 ± 0.2 kcal mol−1, the bond dissociation energy, D00(H—CN) = 124 ± 2 kcal mol−1, and the proton affinity, p.a.(CN−) = 350 ± 1 kcal mol−1.

Sign in / Sign up

Export Citation Format

Share Document