Use of polysulfone capsules impregnated with phosphonium-based ionic liquid for removal of black reactive dye

Abstract

In this study, polysulfone capsules impregnated with the ionic liquid tetradecyltrihexylphosphonium decanoate (IC) were synthesized and applied to remove the reactive dye black (RB) an aqueous solution. The impregnated capsules were characterized by scanning electron microscopy (SEM), surface analysis by Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). Some adsorption parameters were investigated, such as the effect of adsorbent dosage (0.01–1.5 g/30 mL), pH (2–12), and temperature (293–323 K). At pH 8, the dye was completely removed and the process was characterized as exothermic. The kinetic model that best represented the adsorption of RB was the pseudo-first-order. The analysis of the variation of the dye concentration (150–1000 mg L⁻¹) was performed and the Langmuir, Freundlich, and Redlich–Peterson models were presented in their nonlinear form. The maximum adsorption capacity identified by the Langmuir model was \({q}_{max}\) of 276.94 mg g⁻¹, and the capsules could be reused for up to 4 cycles, showing removal percentages above 50% and cumulative loading of 520.8 mg g⁻¹. In addition, a fixed bed column adsorption study was carried out. These results indicate that the proposed material has a high adsorptive capacity and has potential for application in the treatment of industrial textile effluents containing reactive dyes. In addition to considerably reducing the toxic effects of the dye on Lactuca sativa, when compared with pure IL.

Graphical abstract