Volume 48, Issue 4

Sodium deoxycholate (a biosurfactant) in planar chromatography has been used to investigate the separation and migration behavior of transition metal ions. The chromatographic system comprised of soil-cellulose (3:7, w/w) as stationary phase and mixed micellar solution (sodium deoxycholate-sodium dodecyl sulfate, 1.0% each in 1:1 ratio) containing M 5 -acetonitrile in 3:2 ratio (v/v) was identified as the best mobile phase for separation and migration of transition metal ions. The R f value for the metals follows the order, Cu(II) (0.15) < Ag(I) (0.57) < Au(III) (0.91) which also happens to be the order of increasing atomic weight of the metal ions in the periodic group. The detection limit of Cu(II), Ag(I), and Au(III) was found to be 0.22, 1.48, and 7.76 μg zone −1 respectively. The proposed method is robust, sensitive, easy, and reproducible. It has been used for successful identification and separation of above mentioned cations in sample matrices.

A lactobionamide-based polysiloxane surfactant (LBPS) with well-defined structure was prepared via a two-step method. Structure characterization of the LBPS was performed by Fourier Transform Infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance ( 1 H NMR). Surface activity and aggregation behavior in aqueous solution of the LBPS were investigated by surface tension measurements, dynamic light scattering (DLS) and negative-stain transmission electron microscopy (TEM). The results show that the critical micelle concentration (CMC) and surface tension (γ CMC ) at the CMC in aqueous solution of the LBPS are 7.7 mg · L −1 and 27.5 mN · m −1 , respectively, and the surfactants can self-assemble into spherical micelles with diameters in the range from 30 to 250 nm.

The interest in biosurfactant has increased considerably due to their large potential for industrial applications. Rhamnolipid is the simplest class of biosurfactants with well defined structure. The main obstacle in commercialization of biosurfactant especially rhamnolipids is the higher cost of the production that can be reduced by use of inexpensive carbon substrates like glycerol that is readily available from commercial fat-splitting process in the form of sweet water (up to 20% w/v) at very low cost. The composition and structure of various components in crude rhamnolipids synthesized by of Pseudomonas aeruginosa (ATCC 10145) on sweet water, were determined using TLC, HPLC and LC\MS. The crude product showed two distinct components having structure Rha 2 C 10 C 10 and Rha 2 C 10 C 12 at 85.45 wt.% and 14.55 wt.% respectively. The Rha 2 C 10 C 10 was more efficient and effective in surface tension reduction up to 23.5 mN/m than other components. Crude rhamnolipids showed better emulsifying power than its individual components. The crude rhamnolipids showed better foam stability than sodium lauryl sulfate (SLS) at lower concentrations (0.05 to 0.002% w/v). It also enhanced and stabilized the foam produced by SLS at 0.01 to 0.025% of rhamnolipids.

Bisphosphodiester surfactant is a name assigned to a family of synthetic amphiphiles possessing a hydrocarbon chain attached to another hydrocarbon chain via different methylene chains as a spacer derived from α-ω-alkyl dibromide (1,4-DBB, 1,6-DBH and 1,8-DBO). In the present study, a series of bisphosphodiester surfactants having C 14 hydrophobic tail and different methylene chains as a spacer derived from α-ω-alkyl dibromide have been synthesized at 35°C. The effect of reaction variables like temperature, duration and molar ratios of mono tetradecyl phosphate, tetramethyl ammonium hydroxide and spacer on the yield of bisphosphodiester surfactants has also been reported. Modern instrumental techniques viz. FT-IR, 1 HNMR, and 13 CNMR were utilized to characterize the functional groups presence in synthesized bisphosphodiester surfactants. Elemental analysis of synthesized bisphosphodiester surfactants was also carried out. Surface active properties viz. surface tension, interfacial tension, critical micelle concentration and aqueous properties viz. foaming stability, wetting ability, emulsifying ability and dispersing power of synthesized gemini surfactants were also determined. Among all synthesized bisphosphodiester surfactants IIIb had maximum anionic content of 78.9%; and showed highest foaming ability (70 ml), superior dispersing ability (45.7%), whereas IIIc showed low CMC values (0.00026 mmol/l); minimum surface tension and interfacial tension (37.3 mN/m and 31.6 mN/m) respectively.

Two new surfactants (stearoyl morpholinium chloride and palmitoyl morpholinium chloride) were synthesized in two steps. In the first step, chloride acids were reacted with morpholine salt for producing morpholinium normal penta decyl ketone and morpholinium normal hepta decyl ketone. In the second step, the obtained products were reacted with HCl to produce suitable surfactants. The synthesis products in each steps were analyzed by Nuclear magnetic resonance (NMR), Fourier transform infrared spectrometry (FTIR), and elemental analysis. Also, the kinetic of the reactions were investigated. It has been shown that the synthesis reaction of the first step, the low rate step, follows a first order for two surfactants. The properties of two surfactants were investigated for anti-static and surface tension reduction. It was found that the hydrocarbon chain length is the main factor which has an effect on the properties of surfactants.

Trioctyl hydroxyethyl ammonium chloride was synthesized from trioctylamine, hydrochloric acid and ethylene oxide by a two-step process. The structure of the quaternary ammonium salt was characterized by FTIR and 1 H NMR. The surface tension at the critical micelle concentration was measured to investigate the surface activity of it.

Physicochemical behavior of cetyltributylphosphonium bromide (CTBuPB) surfactant in presence of additives (urea, thiourea and sucrose) has been studied by conductometric measurement at 303–320 K. The critical micelle concentration (CMC) and degree of micellar ionization (α), increases with increasing concentration of additives (urea, thiourea and sucrose). The standard Gibbs free energy of micellization (ΔG o m ), enthalpy of micellization (ΔH o m ) and entropy of micellization, (ΔS o m ), have been obtained by applying the mass action model. The free energy and enthalpy of micellization have found to be negative in all the systems.

The critical micelle concentration (CMC) of Cetyltrimethyl ammonium bromide (CTAB) was determined conductometrically in binary mixtures of water + cosolvent at various temperatures and at low concentrations of sodium chloride, ranging from 0.0 to 2.4 × 10 −2 M. Dimethylsulfoxide (DMSO) and acetonitrile (AN) were used as cosolvents added to water. The ability of NaCl to lower the CMC of CTAB in water was inhibited by DMSO and AN. Thermodynamic parameters of micellization ΔH o m , ΔS o m , and ΔG o m were evaluated according to the pseudo-phase model. The contribution of DMSO and AN in the micellization process of CTAB in aqueous electrolyte solutions were discussed in terms of the observed thermodynamic properties.

Functional monomer [N-(2,4,4-trimethylpentan-2-yl)acrylamide] was synthesized and characterized by MS and NMR. A series of high molecular weight cationic polyacrylamides were prepared with N-(2,4,4-trimethylpentan-2-yl)acrylamide, acrylamide and methacryloxyethyltrimethyl ammonium chloride by copolymerization using complex initiation systems as catalysts in aqueous solution. Then they used as flocculants to treat the paper-making wastewater. The removal of the colour and the chemical oxygen demand (COD) in the treated waste water samples were determined. Results showed that flocculants could efficiently remove the color and the COD. The overall color and COD removal efficiencies reached as high as 80% and 85%, respectively.