Adsorption and Removal of Cationic Surfactants by Montmorillonite Clayst

• Published in: Nippon Kagakukai shi (1972) Vol. 1989; no. 7; p. 1144
• Main Authors: ZHAO, Xiaofu, URANO, Kohei, OGASAWARA, Sadao
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Science and Technology Agency 01.07.1989
• ISSN: 0369-4577

The adsorption of cationic surfactants of quaternary ammonium salt on five montmorillonite clays was examined for treatment of wastewater containig cationic surfactant. The adsorption capacities of montmorillonite clays were high as activated carbon and much higher than some other minerals. The adsorption isotherms of the clays of Na type and the other types showed different patterns, and this could be explained by their different behaviors in aqueous solution. Among the clays which have same exchangeable cation, the clay which had higher cationexchange capacity showed larger adsorption ability. The influence of pH on adsorption was small. Coexisting inorganic salts showed a positive effect on adsorption amount due to the increase of micellar aggregation number of the surfactant, and a negative effect due to the interference of cation exchange with the coexisting cation. The positive effect of coexisting anions followed the Hofmeister series: NO3->Cl->SO42-. The negative effect of coexisting'cations was inverse to the series of cation-exchange selectivity: Fe>Al3+>Ca2+>NH4+>Na+. Increase of the basal spacings of the clays with the adsorption indicated that cationic surfactant intercalated in the interlayer space. After adsorption of cationic surfactant on clays, the clay suspension was easily filtrated. t Studies on the Adsorption Abilities of Montmorillonites and Their Application to Water Treatment. tr.