Adsorption of organic phenols onto dual organic cation montmorillonite from water

Single-and multicomponent competitive adsorptions were carried out in a batch reactor to investigate the removal of three toxic organic phenols, 2-chlorophenol, 3-cyanophenol, and 4-nitrophenol, using organically modified montmorillonite. To study the removal capacity of phenolic contaminants dissolved in aqueous solution, two organic cations, tetramethylammonium (TMA) and hexadecyltrimethylammonium (HDTMA), were exchanged for the metal cations on the montmorillonite to the extent of about 40 and 45% of the cation-exchange capacity (CEC) of the montmorillonite, respectively, resulting in a surface property change from hydrophilic to organophilic. From the experimental results it was observed that adsorption affinity on TMA/HDTMA-montmorillonite is in the order 2-chlorophenol > 4-nitrophenol > 3-cyanophenol. The Langmuir and the Redlich-Peterson models were used to analyze the single component adsorption equilibria. On the other hand, the IAST and LCM models were used to predict the multicomponent competitive adsorption equilibria. These models yielded favorable representations of both individual and competitive adsorption behaviors.