NONIONIC ORGANIC PARTITIONING ONTO ORGANOCLAYS

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.