The adsorption of two nonionic organic compounds, nitrobenzene (NB) an
d 1,2-dichlorobenzene (DCB) onto five organoclays was studied. The res
ults of the adsorption Studies were compared to existing models (1-10)
developed to predict nonionic organic adsorption onto the organic fra
ction of natural soils and sediments. The predictions by these models
cori-elate the log of the normalized adsorption partition coefficient
(Kom) and the log of the organic compound's octanol-water partition co
efficient (Kow). The adsorption partition coefficient (Kp) is normaliz
ed hy divided it by the soil's percent organic matter content (OM). Th
e Kom values for NB and DCB adsorption by the organoclays was at least
an order of magnitude higher than existing models would predict. This
was most likely due to the greater efficiency of the organic fraction
of the organoclays to adsorb nonionic organic compounds. A new model
for nonionic adsorption onto organoclays is presented.