Volume 52, Issue 2

This study deals with the synthesis of Pt nanoparticles via oil-in-water microemulsions formulated with the technical grade surfactant BIODAC® 510. For this purpose we studied the influence of the Platinum precursor dimethyl(cyclooctadiene)platinum (Pt(COD)Me 2 ) on the phase behavior of the base microemulsion. It was found that the addition of Pt(COD)Me 2 has nearly no effect on the phase boundaries even at relatively high concentrations. Small angle X-ray scattering data confirmed that the addition of the metal organyl also does not influence the size of the microemulsion droplets. According to transmission electron microscopy (TEM) the size of the resulting platinum nanoparticles is independent on the amount of Pt(COD)Me 2 in the templating microemulsion. This result was rather surprising since it indicates that a greater amount of precursor in the o/w-microemulsion leads to more rather than to larger nanoparticles.

Surface properties of binary surfactant mixtures of α-sulphonated fatty acid methyl ester (MES) with typical surfactants such as fatty alcohol polyoxyethylene ether (AEO 9 ) and sodium alkylbenzene sulfonate (LAS) have been investigated at (298 ± 0.1) K and (318 ± 0.1) K, respectively. The synergistic interaction parameters of each binary surfactant mixture were calculated for the mixed micelles and mixed adsorption layers, then the composition of each binary surfactant mixture in the mixed micelles and mixed adsorption layers was obtained. The results show that the surface properties of each binary surfactant mixture are significantly better than that of any single surfactant in the mixed system. There are strong synergistic effects in the mixed micelles and mixed adsorption layers for each binary surfactant system. Each binary surfactant system exhibits synergism in mixed micelle formation, surface tension reduction efficiency and effectiveness.

As one important parameter for selecting surfactant used in chemistry flooding, here the interfacial tension (IFT) between crude oil and single surfactants Shengli petroleum sulfonate (SHL-PS), α-olefin sulfonate (C 14/16 AOS), fatty alcohol polyethyleneoxy ether sulfonate (C n E m SO) or their mixture using mimic Shengli brine water as solvent were investigated using spinning drop technology. The results showed: Through C 18 E 3 SO has a small ultra-low IFT window, it is more practical and efficient to obtain ultra-low IFT by mixing two or more surfactants other than using single surfactant; the length of hydrophobic tail plays a more important role than oxyethylene group number on the IFT for C n E m SO/SHL-PS; at mass ratio 1:19, both C 14/16 AOS/SHL-PS and C 18 E m SO/SHL-PS systems can lower the IFT to below 10 −2 mN/m, but their mechanisms may be not same.

The reaction kinetics of ninhydrine (Nin) with glycine–glycine dipeptide (Gly) was studied in aqueous solution. The same reaction was studied in micellar solutions of different surfactants such as sodium dioctylsulfosuccinate (AOT) and sodium dodecyl sulfate (SDS). The reaction was also studied in the L2 microemulsion phase of the three systems AOT/heptane/water, SDS/pentanol/heptane/water, CTAB/pentanol/heptane/water. Spectrophotometric measurements were perfomed at 570 nm. The data show that the reaction is first-order with respect to Nin and Gly in all cases. Values of the observed rate constants ( k obs ) increase with increasing concentration of the surfactant in micellar media. AOT was more promotional than SDS. The reaction rate in the presence of different micelles could be explained using a pseudo-phase kinetic model. Association constants of Nin and Gly with surfactant micelles are reported. Values of k obs for the reaction rates in the microemulsion phases are reported. AOT/heptane L2 microemulsion system has been clearly found as the most promotional among all the other studied systems. Association constants of Nin and Gly with surfactant in microemulsion were obtained. The rate was increased with the temperature in aqueous, micellar and microemulsion phases. The activation parameters ΔH*, ΔS* and ΔG* have also been obtained. The reaction rate in different microemulsion media is slightly increased with the change of oil (heptane > hexane > pentane), while co-surfactants (butanol, pentanol and hexanol) have no effect on k obs values in AOT, CTAB or SDS microemulsion.

Activated heavy oil is a favorable blocking agent, because of its good selectivity and recyclability. In this paper, by simulating the reservoir conditions of Tahe Oilfield, the feasibility of water shutoff by activated heavy oil for high temperature, high salinity and high hardness reservoirs has been studied. Based on the reservoir characteristics, a nonionic-anionic compound emulsifier of 2 % MZ-18 + 3 % BH-12 (MZ-18 = nonionic amide emulsifier condensed by long chain carboxylic acid and polyethylene polyamine; BH-12 = anionic sulfonate emulsifier) was screened out as the optimum emulsification system for the activated heavy oil. The W/O emulsion prepared by the activated heavy oil is of high viscosity; besides, its temperature resistance, salinity tolerance and thermal stability were competent to Tahe reservoir. The water shutoff performance of activated heavy oil was evaluated by the physical simulation experiments. The results show that the activated heavy oil can improve the water shutoff performance and flushing resistance performance in a wide range of permeability – from 300 to 1 500 mD. Also it is found that, the water shutoff ability of the activated heavy oil increases with the increase of permeability of the sands, injection rate of blocking agent as well as the displacing rate of displacement fluid.

In this work we aimed our focus at the determination of the zeta potentials of a standard fabric of cotton Empa type (dyed, finished and softened), which was washed in the presence of surfactants and of a copolymer of action DTI – dye transfer inhibition agent –. The copolymer DTI the type VI/PVP, was used. The washing with ecological surfactants such as: a sodium dodecylbenzene sulfonate (LAS) mixed with an non-ionic alkylpolyglucoside (APG) was made. The cotton fabric was dyed with three different direct dyes (with different molecular weights), finished by the resin of DMDHEU (dimethylol dihydroxy ethylene urea) and softened with a microemulsionated compound of ammoniumsilicone. The variation of zeta potential of cotton articles was obtained under the influence of the total concentration and the proportion of mixture of the surfactants anionic with non-ionic, and of these separately. The polymer DTI stayed to constant concentration, when mixing it with the surfactants. The variation of the zeta potentials of the cotton undyed and finished in function of the DTI were obtained.

Rising environmental concerns lead to use of lower temperatures and to reduced water consumption in domestic dishwashing. The development of new dishwashers with reservoir for reusage of water from the final rinse seeks to reduce the costs per cleaning cycle, but leads to concerns about the hygienic conditions of domestic dishwashers, as the presence of stable communities of microorganisms has been reported. This study investigates the hygienic conditions of different types of domestic dishwashers and the long-term effect of process parameters on the hygiene in dishwashers with water reservoirs.

The precipitation of CaCO 3 (calcite, vaterite, aragonite and calcium carbonate hydrates) and CaSO 4 (calcium sulfate anhydride, calcium sulfate dihydrate and calcium sulfate hemihydrates) scale on pipe surfaces widely occurs in numerous industrial processes. For the control of CaCO 3 and CaSO 4 scales, a novel environmentally friendly scale inhibitor, maleic anhydride (MA)-allypolyethoxy carboxylate (APEM9), was synthesized. MA-APEM9 was characterized by Fourier transform infra-red spectroscopy (FT-IR) and 1 H-NMR. The inhibitor property of the MA-APEM9 copolymer towards CaCO 3 and CaSO 4 in the artificial cooling water was studied by static scale inhibition tests. The effect on formation of CaCO 3 and CaSO 4 was investigated with a combination of scanning electronic microscopy (SEM) and transmission electron microscopy (TEM) analysis. The observation showed that MA-APEM9 was a much better inhibitor both for CaCO 3 and CaSO 4 compared to the commercial inhibitors. An inhibition mechanism is proposed. It shows that the interactions between calcium and allyl-terminated PMA are the fundamental impetus to restrain the formation of the scale in cooling water systems. The MA-APEM9 Inhibitor can be used safely in cooling water systems.

Three gemini surfactants with dibenzyl ether spacer (10-B-10, 12-B-12, and 14-B-14) were synthesized and characterized. The surface activity and thermodynamic properties of micellization were determined by surface tension, steady-state fluorescence microscopy, and conductivity methods. The thermodynamic parameters of micellization (Δ mic G 0 , Δ mic H 0 , and Δ mic S 0 ) derived from the electrical conductivity measurement implied that the micellization of these surfactants was driven by enthalpy. The enthalpy–entropy compensation of micellization showed that the stability of micelles increased with increasing alkyl chain length. Finally, we evaluated the effects of alkyl chain length on the interfacial tension, foam ability, and the emulsion stability.

Three new biodegradable cationic surfactants have been successfully synthesized and the synthesis begins with the esterification of lauric acid, myristic acid and palmitic acid with triethanolamine followed by quarterisation with 1-bromo octane. FT-IR and NMR were used in combination to evaluate the structure of the synthesized surfactants. Elementary analysis was performed and the calculated values were in good agreement with the theoretical values. The antimicrobial effect of three surfactants was evaluated by the Well diffusion assay method and they revealed a good effectivness against gram negative bacteria, gram positive bacteria and fungi.