Assessment of Removal Methylene Blue and Green Dye in Water by Adsorption in Aqueous Solution by the Pan Bottom from a Mining Waste from Betaré-Oya

Abstract

This work focuses on the study of the adsorption of methylene blue (BM) and a green dye (CV) in aqueous solution by the pan bottom from a mining waste from Betaré-Oya. The aim is to recover mining waste as an adsorbent. The influence of physico-chemical parameters on the kinetics and isotherm of adsorption of these dyes on the pan bottom was determined. The UV/Visible spectroscopy technique was used for the analyses. The green dye was study at spectral wavelength 570 nm. Green. Adsorption equilibrium times are 15 minutes for these dyes. Experiments show that when the bottom mass of the pan increases, the quantities adsorbed decrease. In fact, it is the adsorption yields that increase from 60 to 80% for BM and from 30 to more than 90% for CV. Variations in pH showed greater adsorption of dyes in basic medium (pH ≥ 10) which indicates that the dyes are cationic. It was also observed that the amounts of BM and CV per unit of pan bottom increase with increasing initial concentration. The experimental data was analyzed by isotherm models. The value of the constant n of the Freundlich model for BM is 1.53, indicating that adsorption is unfavorable, whereas in the case of CV, adsorption is moderate. Langmuir and Temkin models better describe MB adsorption. The mechanism of adsorption of BM and CV is of chemical type. Pseudo-first-order, pseudo-second-order, Elovich and intra-particle kinetic models have been applied on data and the most suitable is the pseudo-second-order kinetic model.