Articulo
Reactive RED 195 dye removal using chitosan coacervated particles as bio-sorbent: analysis of kinetics, equilibrium and adsorption mechanisms
Autor
Pérez Calderón, John Freddy
Santos, María Victoria
Zaritzky, Noemí Elisabet
Institución
Resumen
Chitosan particles (CP) prepared by coacervation technique were used as bio-sorbent material to remove the azo RR-195 dye; removal percentage (%RM) and adsorption capacity (Q) in batch adsorption experiments under different conditions of bio-sorbent doses, agitation speed and pH medium were determined; the maximum pH of dye removal was 4. Different adsorption equilibrium isotherms were tested and Redlich-Peterson was the model that best fitted experimental results. From the adsorption thermodynamic parameters, it was concluded that the adsorption process of RR-195 onto CP is spontaneous, favorable (ΔG<0), endothermic (ΔH>0) and the dye molecules show affinity for the bio-sorbent (ΔS>0). The maximum monolayer adsorption capacity (Qm) of CP was 82.1 mg.g-1 at pH = 4 and 318 K; therefore coacervated chitosan particles are among the top three adsorbent agents for this dye. The %RM was 84.2% in 10 h when the initial concentration of the dye was 300 mg.L-1. The mixed surface reaction and diffusion-controlled kinetic model (MSR-DCK), fitted satisfactorily experimental results, by considering simultaneous mechanisms of diffusion and adsorption process in the active sites. Fourier transform infrared spectroscopy (FTIR) with attenuated total reflection (ATR), scanning electron microscope-energy dispersion spectrometry X-ray (SEM-EDS) and Zeta potential analysis revealed that the interaction between dye molecules and the bio-sorbent are of an electrostatic nature. Desorption/regeneration experiments indicated that CP can be used in adsorptions/desorption cycles for the removal of wastewater containing RR-195. The information presented in this work demonstrates that CP can be a potent eco-friendly bio-adsorbent for the remediation of industrial wastewater. Centro de Investigación y Desarrollo en Criotecnología de Alimentos