This work was aimed at the study of the adsorption mechanism of Reactive Blue 5G dye on activated carbon derived from babassu shells and pyrolyzed oil shale residue. Experiments were undertaken employing a fixed bed reactor at 30°C using continuous systems. To minimize diffusional resistances, the influence of the flow rate was investigated via breakthrough curves at a feed concentration of 35 mg/ᐉ. Breakthrough curves for flows in the range 2-10 mᐉ/min were carried out using bed height of 15.5 cm for activated carbon and 9.5 cm for pyrolyzed oil shale residue, with an inlet diameter of 1.01 cm. From the calculated mass-transfer parameters, it was shown that the minimum resistance to flow occurred at 4 mᐉ/min for activated carbon and at 2 mᐉ/min for pyrolyzed oil shale residue. It was concluded that the sizes of the pores in the adsorbents play an important role in the adsorption mechanism.

Textile industrial wastewaters have significant quantities of dyes. Adsorption processes using industrials rejects may help in the treatment of these effluents. In this context, uptake of Reactive Blue 5G dye by babassu coconut shell activated carbon was studied with upstream flow fixed-bed experiments. First, the minimum flow rate that minimizes the diffusion effects of 4 mL/min was chosen within the range investigated (2-10 mL/min). Then, the breakthrough curves were obtained for this flow rate for different initial dye concentrations (13.15-102.0 mg/L) and temperature of 30 °C. The mass retained until bed saturation in each experiment was used to obtain the dynamic isotherms, which showed a favorable dye uptake behavior with a maximum adsorption capacity of 12.9 mg.g -1 . The irreversible model fitted the experimental data well when compared to Langmuir and Freundlich models. A LDF model simulated the experimental breakthrough curves, and the bed axial dispersion and mass transfer coefficients were estimated.

-In this study the influence of the volumetric flow rate and feed concentration was investigated for the adsorption of the reactive dye Blue 5G. Experiments were carried out in a bed packed with retorted shale, at 30 o C. The ranges investigated were flow rate 2 -10 mL/min and the feed concentration 13-105 mg/L. Mathematical models were used to represent the dynamic sorption. The double resistance model considers the effects of the axial dispersion and the mass transfer resistance of the external film and inside the particles. As a result, the mass transfer coefficient of the external film and the internal mass transfer coefficient were estimated. The Thomas model was used to simulate the experimental data. In this model the fitted parameter was the adsorption kinetic constant. The first model provided an acceptable representation of the dynamic uptake of the reactive dye Blue 5G.