Adsorption of Hydrolyzed Polyacrylonitrile on Kaolinite: I. Effect of Exchange Cation and Anion1
- J. L. Mortensen2
The rate and extent of adsorption of hydrolzed polyacrylonitrile (HPAN) on kaolinite was determined, using HPAN labelled with C14. Continuous mixing in the presence of univalent exchange ions gave steady state adsorption within 4 hours. Langmuir type adsorption isotherms resulted. Saturation adsorption was 2.6 me. HPAN per 100 g. H-Cl-kaolinite.
The exchange cation affected the extent of adsorption of HPAN in approximately the same order as such cations reduce the zeta potential of kaolinite, i.e., Th4+ > Ca2+ > Ba2+ > H+ > NH4+ > K+ > Na+. An anomalous increase in adsorption in the presence of polyvalent exchange cations suggested adsorption at the site of base exchange salt formation. Anions of sodium salts sorbed on kaolinite increased adsorption of HPAN in the order F- > OH- > H2PO4- > Cl- > CH3COO- > NO3- > HPAN.
HPAN was apparently adsorbed as a monolayer on a single set of sites which are most likely “positive spots” on the edge of the kaolinite crystal or which arise from adsorbed or colloidal sesquioxide impurities.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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