Characterizes of Potassium Permanganate Adsorption and its Surface Destruction Products on Solfonated Compressed Coffee Residue

Abstract

A compressed coffee residue was calcinated at the temperature of 400⁰C for 4 hours, , it was analyzed quantitatively and qualitatively  using the X-Ray Fluorescence (XRF) spectroscopy. The carbon was activated with oleum to adsorb potassium permanganate and its surface destruction products. The concentrations of potassium permanganate in the studied solutions were measured using UV-VIS spectrophotometer. The effect of contact time on the adsorption process was studied, it was found that the experimental data followed the pseudo second-order model. The change of potassium permanganate΄ initial concentration was also studied at the temperatures of 20- 30- 40⁰C. The Langmuir, Freundlich and Temkin isotherm models were applied. In addition, the thermodynamic parameters of the surface adsorption interaction ∆G⁰, ∆H⁰, ∆S⁰ were calculated and showed that the surface interaction with potassium permanganate is endothermic and spontaneous . The surface morphology of compressed coffee residue carbon was studied using the Scanning Electron Microscope (SEM), and the Energy-dispersive X-ray spectroscopy (EDX) was used for elemental analysis of carbon surface before and after adsorption. Based on spectral and morphological studies, a mechanism was proposed for potassium permanganate and its destruction products sorption on adsorbent surface.