Indian Journal of Science and Technology

Abstract

Cationic surfactants as new modifiers for clays affect the clay interlayer structure. In this paper the effect of chain length of gemini surfactants on the interlayer changes of Na-montmorilinite and its dye adsorption from waste water has been reported. Several novel quaternary ammonium cationic gemini surfactants having vaious alkyl chain and spacer lengths were synthesized according to reaction of tertiary amine with corresponded alkyl halide. Subsequently organoclays were prepared by intercalation of synthesized gemini cationic surfactants (2–6–2, 2–10–2, 4–6–4, 4–10–4 and 10-6-10 and conventional cationic surfactants (mono)) onto Na-montmorillonite (MMT-Na+) via ion exchange reaction. The structures of the synthesized surfactants were analysed using 1H NMR, 13C NMR and FT-IR spectroscopy techniques. The modified montmorillonite was also characterized by FT-IR spectroscopy of attenuated total reflection (ATR) and X-ray diffraction techniques (XRD). The results show that gemini surfactants have better intercalation than conventional ones. The basal spacing of modified montmorillonite increase with incorporation of gemini surfactants having longer spacer length and chains length. However, gemini surfactant, 4-10-4 and 10-6-10 were more effective in this regards. Dye adsorption experiments show that by surface modification, the adsorption capacity of acid dye improves and MMT-Na+ modified with gemini surfactants show higher dye adsorption capacity compared to the montmorillonite modified with conventional one (Mono) and as the alkyl chain and spacer length of the surfactants increase, this property increases. Our findings show that these kind of modifications on Na-montmorillonite can make it a promising absorbent for organic pollutants such as dye removal from waste water. 
Keywords: Adsorption, Gemini Surfactants, Montmorillonite, Nanoclay, NMR, Surface Modification,