9

screening tests (Moore and Ramamoorthy, 1984). Accordingly,

phenol, 2,4-DCP and PCP are listed as priority pollutants by

the U.S. Environmental Protection Agency (USEPA, 1979).


Table 3-1. Physical properties of the phenolic compounds
 (Verschueren, 1977; USEPA, 1979)


 Parameters Phenol 2,4-DCP PCP

 M.W. 94.1 163.0 266.4

 pKa 10.02 7.85 4.74

 Melting Pt.(C) 41 45 190

 Boiling Pt.(C) 182 210 310

 Vapor Density 3.2 5.62

 Vapor Pressure (Torr) 0.529 0.12 0.00011

 Solubility (mg/1) 93000 4600 14

 Sp. gravity 1.07 1.38 1.98

 Log Kw 1.46 2.75 5.01
 ow
 At 200 C
 ** Aqueous solubility at 200 C


 3.2 Sorption of the Phenolic Compounds


 Sorption is the process of the mass transfer of a

chemical between the solid phase and a liquid phase, such as

between soil and water mixture, which may be described as

 S = Kd C (3-1)

where S is the concentration in the solid phase, C is the

concentration in the aqueous phase, and Kd is the

distribution coefficient. For the purpose of this research,

the term sorptionn" refers to the processes of adsorption