ENVR 200 |
| Organoclays are usually used to prevent the spread of organic contaminants in site remediation and also to clean the organic pollutants by sorption of these contaminants. Toluene was one of the widely used chemicals in industry and was frequently found in petroleum organic contaminated sites. Organoclays were made by montmorillonite modified with different amounts of hexadecyltrimethyl ammonium. The physical and chemical properties of clay and organoclays were studied by elemental analysis, surface area analyzer and X-ray diffraction. The surface area of organoclays decreases with increasing the carbon contents of organoclays. Sorption and desorption kinetics of toluene vapor to organoclays were investigated by the gravimetric method. The apparent diffusivity of toluene with organo-montmorillonites ranges from 10-7 to 10-8 cm2/sec based on the weight change and on the results simulated by a diffusion model. The most sorbed toluene onto organo-montmorillonites desorbed by purging with nitrogen gas after 40 hours. The negative sorption enthalpies of toluene indicated the sorption process is an exothermic process. Experimental results showed that the sorption kinetics of toluene on organoclays was not generally changed by the content of intercalated organic cations under dry conditions. |
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General Papers
6:00 PM-8:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster
Division of Environmental Chemistry |