Removal of Reactive Blue 13 from Dyeing Wastewater by Self-Assembled Organobentonite in a One-Step Process

A bentonite/surfactant one-step process including the self-assembly of organobentonite and removal of pollutants simultaneously has been proposed as a potential superadsorption process for organic pollutant removal, due to its low operation cost and simplified process compared with a traditional organobentonite process. Here, the self-assembly of organobentonite was optimized, and then the optimized process was applied to remove anionic dye (reactive blue 13) from dyeing wastewater. Results showed high removal efficiencies (more than 93 %) of reactive blue 13 in this one-step process. The functions of cationic surfactant were: (i) interaction with dye anions during the initial reaction; and (ii) self-assembly of organobentonite and then applications to remove anionic dyes as adsorbents. The adsorption data of RB13 could be described by Langmuir isotherm model very well, and the adsorption capacity of self-assembled organobentonite was 50 % higher than that of traditional organobentonite. X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) analysis were used to elucidate the adsorption mechanism. Results indicated that self-assembled organobentonite had a larger basal spacing than traditional organobentonite, and CTMA+ and dye were adsorbed on the external surface or intercalated into the interlayer of bentonite.