values for phenol, 2,4-DCP and PCP as

 log K = 3.547 0.421 log WS (R2=0.983) (5-1)
 oc


5.2.3 Batch Desorption.


 The batch desorption data were fitted to the Freundlich

model and the results are presented in Tables 5-9 and 5-10.

Table 5-9 lists the Freundlich desorption parameters of

phenolic compounds in single-compound systems and Table 5-10

are in multi-compound systems. Like the results of

adsorption studies, there are significant differences (t-

test at alpha= 0.05) between single compound and multiple

compound systems.


Table 5-9. Desorption regression parameters of phenolic
 compounds in single-compound systems.


 Compounds pH log KFD ST.DEV.+ b ST.DEV. R2

 [Aquifer material]
 Phenol 5.03 -1.739 0.070 0.510 0.089 0.943
 2,4-DCP 5.03 -1.129 0.034 0.681 0.044 0.992
 PCP 5.01 -0.979 0.052 0.339 0.063 0.936

 [Aquifer material + sludge]
 2ppm NaN3
 Phenol n/a n/a n/a n/a n/a n/a
 2,4-DCP 5.03 -0.880 0.065 0.733 0.089 0.971
 PCP 5.03 -0.656 0.059 0.696 0.089 0.969
 6ppm NaN3
 Phenol 5.03 -1.177 0.058 0.681 0.086 0.976
 2,4-DCP 5.03 -0.861 0.062 0.898 0.073 0.969
 PCP 5.03 -0.654 0.088 0.746 0.132 0.941
 Average
 Phenol -1.177 0.681
 2,4-DCP -0.871 0.707
 PCP -0.655 0.721

 + Log standard deviation of log K values
 Because of the occurrence of bio degradation