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

Abstract

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 min. 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.