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The adsorptive behaviors of crystal violet (CV), cetyltrimethylammonium
(CTMA), and 2-naphthol to montmorillonite (Mt) using a
simultaneous-adsorption process were studied in this work. The adsorption
results showed that under the experimental concentrations both CV and CTMA
were almost completely removed by Mt. XRD and FTIR characterization results
showed that the adsorbed CV and CTMA formed CTMA-CV aggregates within the
interlayer spaces of Mt, and these aggregates served as accommodation
spaces for the adsorption of 2-naphthol. The adsorption isotherms of
2-naphthol fitted linear equation well in the simultaneous-adsorption
process, suggesting that partition should be the dominant mechanism for
uptaking 2-naphthol. Combining the fact that CV alone formed aggregates
showed nonlinear adsorption isotherms and much weaker adsorption capacity
towards 2-naphtol than CTMA alone formed aggregates, one would expect that
CTMA played a dominant role in the adsorption of 2-naphthol to CTMA-CV
aggregates. In addition, the CTMA-CV aggregates have better adsorption
capacity towards 2-naphthol than the combination of CTMA aggregates and CV
aggregates do. FTIR results showed that CV could adjust the arrangement of
CTMA in the CTMA-CV aggregates, which might be the reason for the enhanced
adsorption capacity. Results of this work suggest that montmorillonite can
be used as a low-cost and high-efficient adsorbent for the simultaneous
removal of different types of organic contaminants from water.
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