Viscosity liquid pollutants

Viscosity is a measure of a fluid s resistance to flow. The knowledge of viscosity is needed for proper design of required temperatures for storage, pumping, or injection of hazardous fluids. Define the viscosity terminologies, and provide technical data of typical liquid pollutants for illustration. 

One special extraction mode uses liquids of enhanced fluidity. These are prepared by combining a high proportion of an associated organic solvent with a low-viscosity liquid such as CO,. A comparison of this approach with SFE and SOX in terms of performance in the extraction of phenol pollutants from house dust revealed extraction with enhanced-fluidity liquids to provide results similar to those of SFE and better than those of SOX [170]. 

Phosphorus oxychloride is a highly reactive, low-viscosity liquid reagent, which evolves hydrogen chloride on reaction, requiring environmental pollution control. The reagent frequently leads to generation of alkyl chloride as a by-product. It is very useful for laboratory preparations of mono- and diesters. However, it is the reagent of choice for manufacture of trialkylesters. The major suppliers of phosphorus oxychloride are Rhodia Inc., Lanxess, Israel Chemicals Ltd (ICL), and Thermphos. 

Ka can be defined as a gas-phase transfer coefficient, independent of the liquid layer, when the boundary concentration of the gas is fixed and independent of the average gas-phase concentration. In this case, the average and local gas-phase mass-transfer coefficients for such gases as sulfur dioxide, nitrogen dioxide, and ozone can be estimated from theoretical and experimental data for deposition of diffusion-range particles. This is done by extending the theory of particle diffusion in a boundary layer to the case in which the dimensionless Schmidt number, v/D, approaches 1 v is the kinematic viscosity of the gas, and D is the molecular diffusivity of the pollutant). Bell s results in a tubular bifurcation model predict that the transfer coefficient depends directly on the... 

Supercritical Fluids (SFs) allow analytes to be extracted from solid samples, i.e., marine sediments, faster and more efficiently since they have lower viscosity and higher diffusivity than liquid solvents (56). CO2 is the most widely used supercritical fluid with or without a modifier, e.g. methanol and toluene. A very exhaustive discussion on the role of a modifier in the enhancement of the extraction efficiency was recently published (39). Few procedures have been described in the literature based on SFE of organic pollutants from environmental samples, including PCBs and PAHs (39, 41, 56-59). Generally, the extraction is performed... 

The choice of suitable surfactants and additional chemicals for the decontamination of source zones largely depends on the type of pollutant and the structure of the soil (mainly on adsorption behaviour and hydraulic conductivity). Adsorbed and solid pollutants or very viscous liquid phases cannot be mobilised. Preformed microemulsions, co-solvents or co-surfactants can be favourably used for such contaminations in order to enhance the solubilisation capacity of surfactants. NAPL with low viscosity can easily be mobilised and also effectively solubilised by microemulsion-forming surfactant systems. Mobilisation is usually much more efficient. It is achieved by reducing the interfacial tension between NAPL and water. Droplets of organic liquids, which are trapped in the pore bodies, can more easily be transported through the pore necks at lower interfacial tension (see Fig. 10.2). The onset of mobilisation is determined by the trapping number, which is dependent on... 

Enhanced electrokinetic remediation has been studied in order to remove organic pollutants as well, PAHs in particular. Solubilization and removal of PAHs proved to be heavily hindered by high organic contents of sediment, as well as by the low liquid/solid ratio achievable as compared to chemical washing, as reported in Andreottola et al. (2008) who also underlined the negative influence exerted by the high viscosity of the chemicals adopted on the process yield. 

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