Comparative study of three novel organo-clays modified with imidazolium-based gemini surfactant on adsorption for bromophenol blue

In this paper, an imidazolium-based gemini surfactant [C14-4-C14im]Br2 was fabricated as modifiers of vermiculite, silica nanosheets (from acid treating vermiculite) and montmorillonite. The modified clays were characterized with FT-IR, XRD, TG, EA, SEM and Washburn capillary rise method and investigated regarding the adsorption capacity for bromophenol blue (BPB). These organo-clays under similar availability of modifier show efficient removal for BPB with the order: C14-4-C14im-Vt > C14-4-C14im-SiNSs > C14-4-C14im-Mt. The adsorption processes are discovered fitting pseudo-second-order kinetics and Langmuir isotherm models. The qmax of organo-Vt, organo-SiNSs and organo-Mt calculated with Langmuir isotherm model are 400.19, 230.77 and 220.27 mg g−1, respectively, which prove organo-clays with imidazolium surfactants acquiring superior adsorbability to other known adsorbents. The adsorption capacity get higher with lower pH value and perform a positive correlation with the wettability. It can be concluded that electrostatic and hydrophobic interactions paly critical roles during the process. C14-4-C14im-SiNSs possesses higher adsorption efficiency (R = 99.53% at pH = 2, C0 = 200 mg L−1) noticeably. These provide some ideas for the use of imidazole-containing surfactants in modifying clays for contaminant treatment.