The removal of Rhodamine B from aqueous solution using manganese oxide modified vermiculite

In this study, we prepared and used manganese oxide-modified vermiculite (Mn-MV) as an adsorbent to sequester Rhodamine B (RhB) dye from aqueous solution. Mn-MV was characterized using a Fourier transform infrared (FT-IR) spectrometer, XRF spectrometry and scanning electron microscope (SEM) to identify the functional groups, components and morphology of the sorbent. Analysis of the adsorbent's functional groups revealed the presence of O-H, C-H, C=C, C-O, and C-O-H groups. The experiments were conducted using a batch adsorption procedure. The optimal removal of Rhodamine B (RhB) was achieved with a dosage of 1.75 g of Mn-MV, a pH of 10, and a duration of 45 minutes. The study on the effect of temperature demonstrated that an increase in temperature favoured the removal of RhB using Mn-MV. The data from the kinetic and isotherm models were best described by the pseudo-second-order and Langmuir models. The thermodynamic parameters, ∆H = 6.32 kJ/mol and ∆S = 82.12 J/mol/K, indicate that the adsorption process is endothermic and spontaneous. These results indicate that vermiculite clay has the potential to be a cost-effective adsorbent for the removal of RhB dye.