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[en] The application of a radiotracer technique using tritiated water to predict the irritation potentials of some soap products is demonstrated. Collagen films are treated with 0.5% and 1.0% soap solutions and tritiated water then incubated at 50 degrees centigrade for 24 hours. After incubation, the uptake of tritiated water by the collagen films was measured by liquid scintillation counting. (Auth.). 6 refs., 2 tabs
[en] Highlights: • Hydroxyapatite nanostructures were synthesized by phosphate surfactant. • Spindle-type nanoparticles formed by the oriented attachment mechanism. • Rod-shaped and sheet-like nanostructures formed in the lamellar structure. • Phosphate surfactants act as a capping agent or lamellar template.
[en] We have dispersed graphene in water, stabilized by a range of 12 ionic and non-ionic surfactants. In all cases, the degree of exfoliation, as characterized by flake length and thickness, was similar. The dispersed flakes were typically 750 nm long and, on average, four layers thick. However, the dispersed concentration varied from solvent to solvent. For the ionic surfactants, the concentration scaled with the square of the zeta potential of the surfactant-coated flakes. This suggests that the concentration is proportional to the magnitude of the electrostatic potential barrier, which stabilizes surfactant-coated flakes against aggregation. For the non-ionic surfactants, the dispersed graphene concentration scaled linearly with the magnitude of the steric potential barrier stabilizing the flakes. However, the data suggested that other contributions are also important.
[en] Laboratory effectiveness tests are described for four classes of spill-treating agents: solidifiers, demulsifying agents, surface-washing agents and dispersants. Many treating agents in these four categories have been tested for effectiveness and the results are presented. Solidifiers or gelling agents solidify oil, requiring a large amount of agent to solidify oil-ranging between 16% by weight, to over 200%. Emulsion breakers prevent or reverse the formation of water-in-oil emulsions. A newly-developed effectiveness test shows that only one product is highly effective; however, many products will work, but require large amounts of spill-treating agent. Surfactant--containing materials are of two types, surface-washing agents and dispersants. Testing has shown that an agent that is a good dispersant is conversely a poor surface-washing agent, and vice versa. Tests of surface-washing agents show that only a few agents have effectiveness of 25-40%, where this effectiveness is the percentage of heavy oil removed from a test surface. Results using the 'swirling flask' test for dispersant effectiveness are reported. Heavy oils show effectiveness values of about 1%, medium crudes of about 10%, light crude oils of about 30% and very light oils of about 90%. (author)
[en] Highlights: • Successfully intercalation of dual-surfactants into montmorillonite. • Preparation of phosphonium-ammonium-modified montmorillonites. • Hybrid-organic-montmorillonite (HOMt) with intermediate properties. • Statistical approach to optimize the hybrid montmorillonite properties.
[en] Salaniline, a condensation product of salicylaldehyde and aniline, shows “off–on” fluorescent behaviour with pH in 1:1 (v/v) CH3CN:H2O and when 3% (w/v) anionic sodium dodecylsulphate (SDS) surfactant is present. The fluorescent switch behaviour of salaniline is forced to “off–on–off” type by 3% (w/v) neutral triton X-100 (TX-100) and 3% (w/v) cationic cetyltrimethylammonium bromide (CTAB) surfactant. The fluorescent “on” window is observed in the pH range 8.0–12.5 for TX-100 and 7.0–11.0 for CTAB. Different charge nature of the surfactants affects the protonation/deprotonation behaviour of salaniline differently, hence the photoinduced electron transfer (PET) processes and the fluorescent switch behaviour. -- Highlights: • Salicylideneaniline act as pH dependent “off–on” fluorescent switch in 1:1 (v/v) CH3CN:H2O. • In surfactant micelles TX-100 (neutral) and CTAB (positive) make the fluorescent switch “off–on–off” type while in. • In surfactant micelle SDS (negative) the pH dependent fluorescent switch is “off–on” type
[en] Modified ultrafiltration membranes are prepared and tested in treating oil/water emulsions. Polysulfone ultration membranes are modified ultilizing surface modifing macromolecules and surfactants. For variety of modified membranes, simultaneous experiments in batch(cycle run) modes have been performed. Oil emulsion adsorption on untreated membrane was found to be a major cause of observed decline in membrane flux but oil-surfactant emulsion adsorption on the modified membrane was found to be reduced preminently