Adsorption of Arsenic (V) from a water solution onto a surfactant-modified zeolite,

Jovita Mendoza-Barron , Araceli Jacobo-Azuara, Roberto Leyva-Ramos*, Ma.Selene Berber-Mendoza,Rosa Ma. Guerrero-Coronado, Laura Fuentes-Rubio y J Merced Martínez-Rosales,
Adsorption, 17:489-496., 2011.


In this study a surfactant-modified zeolite (SMZ) was prepared by adsorbing the cationic surfactant hexadec- yltrimethylammonium (HDTMA) bromide on a clinoptilo- lite. The adsorption of the surfactant modified the surface properties of the clinoptilolite and enhanced the anionic capacity of the SMZ. The adsorption equilibrium data of As(V) from the water solution on the SMZ were obtained in a batch adsorber, and the Langmuir isotherm matched the data reasonably well. The As(V) adsorption capacity of the SMZ was 12.5 times greater than that of the clinoptilolite. The adsorption of As(V) on SMZ was mainly due to the interactions between the anionic sites of the SMZ and the Hads Heat of adsorption, KJ/mol As(V) anions in water solution. The adsorption capacity of the SMZ was dependent on the solution pH. The adsorption capacity was increased and decreased by augmenting the pH from 5 to 7 and from 7 to 12, respectively. This unusual behavior was due to the fact that the affinity of the As(V) for the SMZ was dependent on the As(V) species that were present in solution. The adsorption capacity of the SMZ was slightly favored by decreasing the tempera- ture from 25 to 15 °C. The heat of adsorption was estimated to be Hads = −46.82 KJ/mol, indicating that the adsorption was exothermic and the As(V) was chemisorbed on the SMZ.