Design of a Fixed Bed Adsorption Column and Modelling of Operating Parameters for the Removal of Methylene Blue in Dynamic Mode

Abstract

This study investigates the potential of using the mixture of titaniferous sand and attapulgite as adsorbents in a fixed bed adsorption process to remove a synthetic dye such as methylene blue in aqueous media. The different adsorbents were characterised by X-ray fluorescence spectroscopy and infrared spectroscopy. The different physico-chemical parameters such as pH, zero charge potential, bulk and absolute density, porosity and specific surface area were determined. The sizing algorithm used resulted in a number of transfer units (NUT) equal to 20.109, a height of transfer unit (HUT) equal to 0.515, a material transfer coefficient (Kya) equal to 3.159 and a height of the column (Z) equal to 1.05m. The influence of different experimental parameters such as initial dye concentration, adsorbent bed height and feed rate on the breakthrough curve was investigated. Various simple mathematical models such as Adams-Bohart and Thomas were applied in order to study the dynamic behaviour of the column and to estimate some kinetic coefficients through the experimental data obtained from the dynamic studies performed on the fixed bed. The results showed that the Thomas and Adams-Bohart models perfectly describe the behaviour of the breakthrough curves with values of coefficients of determination R2 that are higher than 0.90 except for the concentration of the dye equal to 50mg/L which has a coefficient R2 equal to 0.88.