Removal of ethyl, isobutyl, and isoamyl xanthates using cationic gemini surfactant-modified montmorillonites

Abstract

Xanthate is a widely used collector in the flotation of sulfide minerals and discharge of xanthate-bearing solution could cause detrimental effects on ecological balance. In this study, the cationic gemini surfactant, butane-1,4-bis(dodecyl dimethyl ammonium bromide) (gBDDA), was applied to modify montmorillonite (Mt) for removal of ethyl, isobutyl, and isoamyl xanthates from aqueous solution. Different amounts of gBDDA that were stoichiometrically equivalent to 0.5 and 1.0 times the cation exchange capacity of Mt were used to investigate the effects of gBDDA dosage on xanthates removal by the obtained products (gOMt). Characterization results of gOMt by X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis showed the successful intercalation of gBDDA into the interlayer space and the higher content of gBDDA on the external surface of gOMt-1.0. Ion exchange and hydrophobic interaction accounted for the similar adsorption capacities of gOMt-1.0 for three xanthates (ca., 0.6 mmol/g), regardless of the molecular structure of xanthates. The rapid adsorption rate and high selectivity of gOMt to xanthates were obtained as supported by the complete removal within 60 min and the stable uptake in the sulfate-coexisting system, respectively, suggesting that gOMt could be a promising adsorbent for removal of xanthates from aqueous solution.