sodium-dodecyl-sulfate and benzenesulfonic-acid

Sulfur hexafluoride (SF(6)) has been widely used in a variety of industrial processes, but it is one of the most potent greenhouse gases. For this reason, it is necessary to separate or collect it from waste gas streams. One separation method is through hydrate crystal formation. In this study, SF(6) hydrate was formed in aqueous surfactant solutions of 0.00, 0.01, 0.05, 0.15 and 0.20 wt% to investigate the effects of surfactants on the hydrate formation rates. Three surfactants, Tween 20 (Tween), sodium dodecyl sulfate (SDS) and linear alkyl benzene sulfonate (LABS), were tested in a semi-batch stirred vessel at the constant temperature and pressures of 276.2 K and 0.78 MPa, respectively. All surfactants showed kinetic promoter behavior for SF(6) hydrate formation. It was also found that SF(6) hydrate formation proceeded in two stages with the second stage being the most rapid. In situ Raman spectroscopy analysis revealed that the increased gas consumption rate with the addition of surfactant was possibly due to the increased gas filling rate in the hydrate cavity.

Topics: Air Pollutants; Benzenesulfonates; Crystallization; Greenhouse Effect; Kinetics; Polysorbates; Sodium Dodecyl Sulfate; Sulfur Hexafluoride; Surface-Active Agents

In previous studies in which in vivo confocal microscopy (CM) was used, quantifiable differences were identified in the corneal epithelium and stroma for surfactants producing different degrees of ocular irritation. In the present study, in vivo confocal microscopy was used to determine area and depth of the initial corneal changes, and the correlation of the data to cell death was characterized by ex vivo live-dead assay.. In four groups of rabbits (12 animals each), 10 microl surfactants known to produce slight, mild, moderate, or severe irritation was applied to the central cornea of one eye; 4 untreated rabbits served as controls. Measurements of group total mean epithelial thickness, epithelial cell area, and depth of keratocyte loss in four corneal regions were made by in vivo CM in 6 rabbits of each group and in 4 control animals at 3 hours and in the remaining rabbits at 3 hours and 1 day. Corneas were then removed and fixed for conventional histologic examination (two eyes/treatment/group), or regions were excised and placed in culture media containing 2 microM calcein-acetoxymethyl ester (calcein-AM) and 4 microM ethidium homodimer. Using laser scanning CM, the number of dead epithelial or stromal cells in a 300 x 300 x 170 microm (in the x, y, and z axes, respectively) volume of the cornea was determined.. Confocal microscopy showed that application of the slight irritant resulted in decreased epithelial thickness at 3 hours (41.2+/-2.6 microm in treated eyes versus 43.6+/-3 microm in control eyes; n=6 and 4, respectively) and a significant decrease (P < 0.001) in epithelial cell size (630+/-203 microm2 versus 1427.2+/-90.7 microm2). On day 1, mild, moderate, and severe irritants caused complete loss of epithelium and disappearance of keratocytes to a depth of 30.8+/-10.7 microm, 47.2+/-10.4 microm, and 764.6+/-159.6 microm (n=6, 5, and 6), respectively. At 3 hours, live-dead assay detected more dead epithelial cells as a percentage of total surface cells (49.2+/-4.5% in slightly irritated eyes versus 20.9+/-3.2% in control eyes), significantly correlating with the measurement by in vivo CM of average epithelial cell size in each eye (r=-0.96; P < 0.005). On day 1, mild and moderate irritants showed increasing stromal cell death from 9.8+/-16.2 cells to 36.4+/-17.7 cells, which significantly correlated with the depth of stromal injury determined by in vivo CM (r=0.79; P < 0.00001). No surviving keratocytes were detected in severely irritated eyes.. The data support the hypothesis that differences in surfactant-induced ocular irritation are directly related to area and depth of acute corneal injury.

Topics: Animals; Benzenesulfonates; Burns, Chemical; Cell Count; Cell Death; Cell Survival; Cetrimonium; Cetrimonium Compounds; Cornea; Epithelium, Corneal; Eye Burns; Female; Fibroblasts; Rabbits; Sodium Dodecyl Sulfate; Surface-Active Agents