OCTADECYL AND AMINO MIXED GROUPS MODIFIED TITANATE NANOTUBES FOR SELECTIVE ADSORPTION OF CATIONIC AND ANIONIC SURFACTANTS

摘要

In this study, octadecyl (C18) and aminopropyl groups modified titanate nanotubes (C18/NH2-TNs) were prepared successfully with silylation method by introducing octadecyltrimethoxysilane (ODS) and aminopropyltrimethoxysilane (APS) simultaneously to titanate nanotubes (TNs) surface. The results suggested that C18/NH2-TNs possessed the obvious characteristic of C18 and aminopropyl groups and showed good water dispersibility. Due to the cooperative effect of alkyl and aminopropyl groups coupled with the residual hydroxyl groups on its surface, C18/NH2-TNs exhibited excellent affinity efficiency to ionic surfactants under different solution pH. The highest uptake efficiency of anionic (perfluorooctane sulfonate, perfluorooctanoic acid and sodium dodecyl sulphate), and cationic (cetyltrimethylammonium bromide) analytes on C18/NH2-TNs could be reached by adjusting solution pH to acid and alkaline conditions respectively. Since C18/NH2-TNs possessed large surface areas and strong affinity ability to ionic organic compounds with long alkyl chains, it showed significantly higher adsorption capacity for perfluorooctane sulfonate than activated carbon and anion-exchange resin. This material was expected to provide a new tool for preconcentration or removal of ionic organic contaminants from water samples.