Electroacoustic and ultrasonic attenuation measurements of droplet size and ζ-potential of alkane-in-water emulsions: effects of oil solubility and composition

Abstract

The effects of oil solubility and composition on the zeta potential and drop size of oil-in-water emulsions stabilised by sodium dodecyl sulfate (SDS) were studied by electroacoustics and ultrasonic attenuation. The zeta-potentials of toluene and alkane emulsions were found to decrease (be less negative) as the water solubility of the dispersed oil phase increased. The zeta-potentials also depended on the composition of mixed oils, becoming more negative with increasing mole fraction of an insoluble oil (hexadecane). As the water solubility of the dispersed oil phase increased, the conductance within the Stern layer relative to the diffuse layer (K/K) increased, which is interpreted as due to the displacement of the shear plane further into the diffuse layer. The shear plane was calculated to increase from approximately 0.50 nm at the insoluble oil-water interface (hexadecane) to approximately 2.5 nm at a soluble oil-water interface of toluene. The lowering of the zeta-potentials of the soluble oils is ascribed to the shift of the shear plane into the diffuse layer, resulting in a more diffuse interface. The total surface conductance of the mixed oils was related to the log of the oil solubility and decreased from approximately 7 x 10(-9) Omega(-1) to 3 x 10(-9) Omega(-1) with increasing oil solubility from hexadecane to toluene, respectively. The lower surface conductance at the soluble oil-water interface is attributed to a reduction in the dielectric constant of the water inside of the shear plane, caused by the presence of the soluble oil.

Changes in Colloidal Properties of Oil in Water Emulsions Stabilized with Sodium Caseinate Observed by Acoustic and Electroacoustic Spectroscopy

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Biomass Modification Using Cationic Surfactant Cetyltrimethylammonium Bromide (CTAB) to Remove Palm-Based Cooking Oil

“…However, spontaneous protonation and deprotonation of surface functional groups still can influence the adsorption. Oil droplets and hydrocarbon often carry negative charge in aqueous solution [34]. erefore, at pH 2, due to the opposite charge hydrogen ions, the droplet repulsion forces decreased and coalescence occurs apparently serving to rapid demulsification.…”

Акустооптическая Модуляция И Отклонение Электромагнитного Излучения Терагерцевого Диапазона В Неполярных Жидкостях

“…Впервые проведенная систематизация ряда свойств жидкостей поз-волила собрать в таблице данные по АО-характеристикам жидких сред на длине волны λ = 130 µm, а также коэффициентам поглощения мощности α электромагнитного излучения и коэффициентам затухания амплитуды α s акустической волны, нормированным на квадрат часто-ты F ультразвука [3][4][5][6][7][8][9][10][11]. Значения плотности ρ можно найти в тех же работах, в которых приведены значения скорости звука V .…”