Synthesis of organic rectorite with novel Gemini surfactants for copper removal

Graphical abstract: Three Gemini surfactants showed stronger rapid intercalation capacity into rectorite and behaved better on Cu²⁺ removal than two single-chain surfactants, which were positive to their increasing amount and chain length. - Highlights: • Modification of rectorite (REC) with several surfactants was performed in 1 h. • The arrangement of Gemini surfactants in REC layers was discussed. • All ORECs displayed better adsorption capacities on Cu²⁺ than pure REC. • Gemini-REC behaved better than single-chain surfactant modified REC on Cu²⁺ removal. • The adsorption capacity was positive to the amount and chain length of surfactant. - Abstract: Three novel Gemini surfactants were used to prepare organic rectorite (OREC) under microwave irradiation, in comparison with single-chain surfactant ester quaternary ammonium salt (EQAS) and cetyltrimethyl ammonium bromide (CTAB). The structure and morphology of OREC were characterized by XRD, BET, FT-IR, TEM and TGA. The removal of Cu²⁺ on OREC from aqueous solution was performed. The results reveal that Gemini surfactants modified REC had larger interlayer distance and higher surface area than single-chain surfactants EQAS and CTAB, and the increasing amount or chain length of Gemini surfactants led to larger layer spacing and higher adsorption capacities. The adsorption behavior of Gemini surfactant modified REC can be better described by Freundlich adsorption isotherm model, with a maximum adsorption capacity of 15.16 mg g⁻¹. The desorption and regeneration experiments indicate good reuse property of Gemini modified REC adsorbent. Therefore, this study may widen the utilization of Gemini surfactants modified layered silicates