Analysis and modeling of column operations on reactive dye removal onto alkaline-treated biomass fly ash

The adsorption characteristics of Reactive Black 5 (RB5) dye on alkaline-treated biomass fly ash (TFA) were investigated in aqueous solutions in a fixed-bed column. The breakthrough curves increased with decreasing initial dye concentration and the flow rate, and with increasing bed depth. In this column study, the optimum flow rate and bed depth were 5 ml min(-1) and 10 cm, respectively. The Thomas model provided a good prediction of the breakthrough curve of RB5 removal by the TFA. The maximum adsorption capacity from the column study was in accordance with the equilibrium capacity in a batch experiment. The bed-depth service time model was used to describe the effect of bed depth on the breakthrough curves, and it revealed a good fit with the experimental data. These results suggest that the fixed-bed TFA is suitable for treating dye wastewater.