Surfactant-coated Tea Waste: Preparation, Characterization and its Application for Methylene Blue Adsorption from Aqueous Solution

Abstract

This paper reports on the development of organo-modified tea waste (TW) adsorbent prepared by using sodium dodecyl sulfate (SDS) for removing methylene blue (MB), a model cationic dye, from aqueous solution. The natural and modified samples were characterized by scanning electron microscope (SEM), nitrogen physisorption and Fourier transform infrared spectroscopy (FT-IR). Batch adsorption experiments were carried out to remove MB from its aqueous solutions using SDS coated TW (SCTW). Analysis of adsorption results obtained at different temperatures showed that the adsorption pattern on the SCTW can be described perfectly with Langmuir isotherm model compared with Freundlich isotherm model. The adsorption process has been found exothermic in nature and thermodynamic parameters have been calculated. The adsorption kinetic followed the pseudo-second order kinetic model. Desorption studies suggest that MB adsorption onto the SCTW should be mainly controlled by the hydrophobic interaction mechanism, along with a considerable contribution of the cationic exchange mechanism.