Buriti fibers were subjected to an alkaline pre-treatment and tested as an adsorbent to investigate the adsorption of copper, cadmium, lead and nickel in mono- and multi-element aqueous solutions, the results showed an increase in the adsorption capacity compared to the unmodified Buriti fiber. The effects of pH, adsorbent mass, agitation rate and initial metal ions concentration on the efficiency of the adsorption process were studied using a fractional 2(4-1) factorial design, and the results showed that all four parameters influenced metal adsorption differently. Fourier transform infrared spectrometry and X-ray fluorescence analysis were used to identify the groups that participated in the adsorption process and suggest its mechanisms and they indicated the probable mechanisms involved in the adsorption process are mainly ion exchange. Kinetic and thermodynamic equilibrium parameters were determined. The adsorption kinetics were adjusted to the homogeneous diffusion model. The adsorption equilibrium was reached in 30 min for Cu(2+) and Pb(2+), 20 min for Ni(2+) and instantaneously for Cd(2+). The results showed a significant difference was found in the competitiveness for the adsorption sites. A mathematical model was used to simulate the breakthrough curves in multi-element column adsorption considering the influences of external mass transfer and intraparticle diffusion resistance.
RESUMO
ABSTRACTIn this study were performed the kinetics and isotherms of adsorption of the ions Fe (III) from synthetic affluent using activated carbon from coconut shell as adsorbent. The objective was to obtain the equilibrium and kinetic parameters of the process and thereby simulating different operating conditions in a adsorption column fixed bed. It was evaluated the influence of three temperatures different on the adsorption of Fe (III), in which the temperature increase indicated adsorption exotherm.The Freundlich isotherm showed the best fit to the experimental data.At the kinetic study the model that best fit to the experimental data was the model Pseudo-First Order for the three concentrations studied.The finite volume method was used for discretization of the mathematical equations and a computational algorithm was implemented in FORTRAN.The computational code was validated with experimental data found in the literature (maximum error of 6.2%) can thus simulate different operating conditions of the system.
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