Phenol sorption on surfactant-modified Mexican zeolitic-rich tuff in batch and continuous systems.

Surfactant modified clinoptilolite-rich tuff was used for the removal of phenol from aqueous solutions. The zeolitic rock from Oaxaca (Mexico) was treated with sodium chloride and then modified with hexadecyltrimethylammonium chloride or bencylcetildimethylammonium chloride in different experimental conditions. Phenol sorption isotherms and column experiments were performed; in both cases, phenol was determined in the aqueous solutions by UV-vis spectroscopy. The results showed that the sorption of phenol depends on the quantities of surfactant in the zeolitic rocks, the kind of surfactant, modification conditions and pH of the solutions. When the initial concentration of phenol increased, the adsorption of phenol in the surfactant-modified zeolite increased and the experimental data was best adjusted to the Langmuir model. The saturation of the columns rapidly reached high percentages.

Effects of preparation and experimental conditions on removal of phenol by surfactant-modified zeolites.

The removal of phenol from aqueous solutions using surfactant-modified clinoptilolite-rich tuffs (SMZ) prepared from two Mexican zeolitic tuffs (Chihuahua and Oaxaca) was investigated. Sodium homoionization of the zeolitic rocks was performed before they were modified with the surfactants: hexadecyltrimethylammonium chloride or bromide and bencylcetildimethylammonium chloride. The surfactants in the modified zeolitic materials were determined considering the total carbon in the samples. The phenol removal was determined in a batch system taking into consideration the different quantities of surfactants in the zeolitic tuffs, contact time, pH and initial phenol concentration. The phenol was determined in the aqueous solutions by UV/Vis spectroscopy. Results showed that the formation of a hemimicelle or admicelle on the zeolites depended on the initial surfactant concentration and they were responsible for the type of interactions between the phenol and the surfactant-modified zeolites. Phenol adsorption by the surfactant-modified zeolites was carried out in approximately three hours. Phenol adsorption data was best adjusted to the pseudo-second order kinetic model. Both, surface properties of the surfactant-modified zeolites and pH of solution play an important role in the removal of this pollutant from aqueous solutions and they are responsible for the type of mechanism involved.