Kinetics and thermodynamics of Malachite Green dye removal from aqueous phase using iron nanoparticles loaded on ash

Abstract

Iron nanoparticles loaded on ash (nFe-A) synthesized from a natural source i.e. Rosa canina L. leaves (as agricultural waste), were used as adsorbent for the rapid removal of the toxic Malachite Green (MG) dye from the liquid phase. Several effective parameters such as solution pH, initial dye ion concentration, contact time, adsorbent dosage and temperature were well studied and optimized using a batch adsorption method. The obtained experimental data revealed that a maximum amount of MG ions was removed within 5min of contact time, hence it is the optimized contact time and after the 30min of commencement of every experiment the equilibrium is attained, additionally the optimized value for initial dye ion concentration and solution pH was found to be 50mg/l and 8 respectively. The adsorption equilibrium and kinetic data were well fitted and found to be in good agreement with the Langmuir isotherm model and pseudo-second-order-model. Moreover the negative value of ΔG° reveals the spontaneous nature of the adsorption process and the positive values of ΔH° and ΔS° indicate that the adsorption process is endothermic and entropy driven.