A numerical and experimental study of the monocomponent and multicomponent adsorption and desorption of BTX compounds (benzene, toluene, and o-xylene) in a batch reactor and fixed-bed column was carried out in aqueous solution at 23 °C, using coconut shell activated carbon as the adsorbent. The monocomponent Langmuir isotherm model best represented the experimental results (average R 2 = 0.9952) and the multicomponent Langmuir model, using the multicomponent parameters, represented the multicomponent data obtained in a fixed-bed column better than the monocomponent model. The equations which describe the phenomenology were discretized using the Finite Volumes Method with the WUDS and CDS formulations. The results for the monocomponent breakthrough curves obtained through simulation showed good agreement when compared with the experimental data (maximum error of 11.52%). For the monocomponent breakthrough curves the greatest deviation was observed for the compound which had the least affinity for the solid phase (benzene). The best results for the desorption of the BTX compounds from the adsorbent were obtained using ethanol as the desorbent solvent, and the average removal percentages in three cycles of regeneration in the column were 90% for benzene, 82% for toluene, and 78% for o-xylene.

An experimental and numerical study of the individual and competitive adsorption of BTX compounds (benzene, toluene, and o-xylene) in aqueous solution was carried out in a fixed-bed column filled with activated carbon. The equations of transport were discretized using the finite volumes method and an algorithm was implemented in the Fortran programming language. The results obtained in all cases showed that o-xylene is the contaminant which is most competitive for the active site of the adsorbent, and over time it is able to desorb the compounds which have a lower affinity and adsorb to the free active sites. The result is that the local concentration of the weakly adsorbed component in the fluid phase is higher and surpasses the dimensionless concentration. This finding appeared to be related to the Biot number. As the Biot number increased the rate of competitive adsorption decreased, and the form of the breakthrough curves is flat with a lower breakpoint. This is due to the low intraparticle resistance and also the reduced contact time required to reach saturation.

2015): Multielement adsorption of metal ions using Tururi fibers (Manicaria Saccifera): experiments, mathematical modeling and numerical simulation, Desalination and Water Treatment, A B S T R A C TA numerical and experimental study of the multielement adsorption of Cd 2+ , Cu 2+ , Ni 2+ , and Pb 2+ metal ions in batch and column system were carried out in aqueous solution using Tururi fibers as adsorbent. The kinetics and thermodynamic equilibrium parameters were studied. The adsorption kinetics was fitted to the homogeneous diffusion model and the results showed good linear correlation coefficients. Furthermore, a mathematical model was built to describe the mass transfer kinetics for fixed bed column tests. The effects of constant adsorption equilibrium, external mass transfer, and intraparticle diffusion resistance on breakthrough curves were studied. The equations which describe the phenomenology were discretized using the finite volumes method with the weight upstream differencing scheme and central difference scheme formulations. The results for the breakthrough curves obtained through simulation showed good agreement compared with the experimental data.

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.

The adsorption of aqueous solutions of BTEX (benzene, B; toluene, T; ethyl benzene, E; and xylenes, X) on hydrophobically modified zeolite was investigated. Multicomponent kinetics and equilibrium studies were carried out using a batch system. Furthermore, a mathematical model was studied that considers the mass transfer kinetics in a fixed-bed adsorption system. The influences of external mass transfer as well as the constant adsorption equilibrium and intraparticle diffusion resistance on breakthrough curves were evaluated. The adsorption kinetics was adjusted to the homogeneous diffusion model. The breakthrough times of the BTEX compounds increased with an increase in the bed height of the adsorbent and decreased with an increase in the flow. The mathematical model and numerical methodology that were applied represented the data of the present adsorption process with good accuracy.