ABSTRACT
Summary In th is study , w e h av e in v estig a ted th e so rp tio n b eh a v io r o f tw o g ro u p s o f H O C s on th ree natu ra l g eo lo g ica l m a teria ls . T h e so rp tio n w as o b se rv e d to be n o n lin e a r fo r all so rb a te s e x c ep t b en z en e on D o v e r D G S L , and a lso fo r th e m o re h y d ro p h o b ic ch em ica ls on D o v e r O S C L an d D u k e so il A . In all ca se s, th e ap p a ren t ex ten t o f iso th e rm n o n lin ea rity w as o b se rv e d to in c rease w ith H O C h y d ro p h o b ic ity . A co m p o s ite a d so rp tio n -p a rtitio n in g m o d e l w ith th e L an g m u ir type eq u a tio n fo r th e ad so rp tio n c o m p o n en t has b een u se d to in te rp re t th e o b se rv e d so rp tio n b eh av io r. T h e m o d e lin g resu lts sh o w ed th a t th e to ta l av a ila b le n o n lin e a r ad so rp tio n cap ac ity is h ig h e r fo r liq u id ch e m ic a ls th an c h e m ic a ls th a t are e x p e c ted to ad so rb in th e so lid s ta te at th e te s t tem p era tu re . A s d esc r ib ed e lsew h e re [17], th is la tte r re su lt is c o n s is te n t w ith a P o lan y i-b a sed in te rp re ta tio n o f th e data. A n in te res tin g asp ec t to o u r co m p o s ite iso th e rm s is th a t th e c o m b in a tio n o f ad so rp tio n an d p a rtitio n in g lead s to a m o re p ro n o u n ce d o v era ll n o n -lin ea rity fo r th e m o re h y d ro p h o b ic so lu tes.
