Organic pollutant , water solubility

S. W. Karickhoff and D. S. Brown, determination of Octanol Water Distribution Coefficients, Water Solubilities, and Sediment/Water Partitions Coefficientsfor Hydrophobic Organic Pollutants, EPA-600/4-79-032, report, EPA, Washington, D.C., 1979. 

As indicated above, industrial wastewater contains avast array of pollutants in soluble, colloidal, and particulate forms, both inorganic and organic. In addition, the required effluent standards are also diverse, varying with the industrial and pohutant class. Consequently, there can be no standard design for industrial water-pohution control. Rather, each site requires a customized design to achieve optimum performance. However, each of the many proven processes for industrial waste treatment is able to remove more than one type of pollutant and is in general applicable to more than one industry. In the sections that follow, waste-treatment processes are discussed more from the... 

Barac T, S Taghavi, B Borremans, A Provoost, L Oeyen, JV Colpaert, J Vangronsveld, D van der Lelie (2004) Engineered endophytic bacteria improve phytoremediation of water-soluble, volatile, organic pollutants. Nat Biotechnol 22 583-588. 

Sauve S., McBride M.B., Norvell W.A., Hendershot W.H. Copper solubility and speciation of in situ contaminated soils Effects of copper level, pH and organic matter. Water Air Soil Pollut 1997 100 133-149. 

Another feature of the process is that the sorption capacity of type II organoclays is inversely related to the aqueous solubility of the NOCs (Chiou 1989). For example, the affinity of HDTMA-smectite for various phenols increases in the order phenol < chlorophenol < dichlorophenol < trichlorophenol since phenol is the most water-soluble while trichlorophe-nol is the most hydrophobic (Mortland et al. 1986, Lo et al. 1998). The relationship between the distribution (partition) coefficient in a type II organoclay and water-solubility is illustrated in Fig. 5 for a range of nonionic organic pollutants. 

Fig. 5. Relationship between the distribution (partition) coefficient on dimethyl dihydrogenated tallow montmorillonite for a range of non-ionic organic pollutants and their corresponding solubility in water. BHC is benzene hexachloride, the y-isomer of which is known as lindane aroclor 1232 and aroclor 1252 denote mixtures of polychlorinated biphenyls containing about 32 and 52% chlorine, respectively. After Beall (2003).

Okouchi, H., Saegusa, H., Nojima, O. (1992) Prediction of environmental parameters by adsorbability index water solubilities of hydrophobic organic pollutants. Environ. Inti. 18, 249-261. 

Each type of technique can be applied in several modifications. Microbiological degradation processes offer the possibility to purify wastewater streams which contain a wide range of organic pollutants. In contrast, physical/chemical techniques are much more specific. The quality of the purified water regarding residual amounts of soluble organic pollutants, and colloidal and suspended particle pollutants, strongly depends on the type of treatment process and the applied treatment conditions. Very often a combination of different types of treatment techniques is necessary to satisfy the effluent quality required (for example a combination of anaerobic and aerobic treatment). 

It is well known that complexation of trace elements by both inorganic and organic ligands plays an important role in their transport through natural waters, influencing their solubility and their adsorption on both bottom and suspended sediments. In many cases organic pollutants have been shown to complex with a wide variety of cations and, in particular, many of these pollutants have been shown to complex with iron (157). It is possible that there will be a similar complexation of... 

The most important properties of an organic pollutant which determine its mode of interaction with SPHS/SP0M are the chemical character of the molecule, shape and configuration, acidity (plCa) or basicity (pKb), water solubility, polarity, molecular size, polarizability, and charge distribution. 

The presence of water-soluble macromolecules in solution at submicel-lar concentrations has been reported to enhance the water solubility of hydro-phobic organic chemicals in several instances [19, 106, 113]. The presence of macromolecules in solution can enhance the apparent solubility of solutes by sorptive interactions in the solution phase. The processes by which macromolecules enhance the solubility of pollutants are probably variable as a function of the particular physical and chemical properties of the system. A macromolecule possessing a substantial nonpolar region can sorb a hydrophobic molecule, thereby minimizing the interfacial tension between the solute and the water. 

Application of pollutant chemodynamic models, which neglect the DHS phase, may result in inaccurate estimations of apparent solubility and transport parameters. The impact of a DHS solubility enhancement is most pronounced for the least water-soluble solutes. The affinity of a solute for a DHS is a function of the same properties, which drive a complex organic mixture(s) to sorb onto the stationary solid phase, namely bonding interactions and hydrophobicity. 

Hence, DHS will manifest the greatest solubility enhancement for those pollutants which are the least soluble in water or the most attracted to the solid phase. Organic pollutants, which are soluble in water, are less likely to be sorbed onto the solid or colloidal phase in the absence of specific bonding interactions. 

Chiou, C.T., Malcolm, R.L., Brinton, T.I., and Kile, D.E. Water solubility enhancement of some organic pollutants and pesticides by dissolved humic and fulvic acids. Environ. Sci. Technol, 20(5) 502-508, 1986. 

Solvent extraction has many features that make this separation technique applicable for the removal of organic pollutants from wastewater. The organic solutes can be recovered, and there is thus a potential for economic credit to the operation. In comparison with biological treatment, it is not subject to toxicity instabilities. The disadvantage is that, even with solvents having low solubilities in water, solvent losses can be substantial owing to... 

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