Removal of a reactive textile azo dye by dolomitic solids: kinetic, equilibrium, thermodynamic, and FTIR studies

Abstract

AbstractAlgerian dolomite was treated at different temperatures in the 600–1000°C range and characterized by XRD and SEM. The obtained samples, named dolomitic solids, were used in the removal of Reactive Black 5 (RB5) from aqueous solutions. A literature survey shows that the data about the dye adsorption by dolomites are almost non-existent. Kinetic data, equilibrium isotherms, thermodynamic parameters, pH influence, and FTIR study were considered. The kinetic mechanism is enough complex, involving different models such as those of pseudo-second-order, intraparticle diffusion, and Elovich. For all dolomitic solids, the capacity in RB5, at equilibrium, strongly increases with increasing adsorption temperature. The affinity sequence is D900 (dolomite treated at 900°C) > D800 > D1000 > D600 > raw dolomite. Knowing that D900 adsorbs 125.9 mg g−1, it appears very effective for removing reactive dyes from wastewaters. The isotherms are found to be overall well represented by the Redlich–Peterson equation. The...