Vanadium separation with activated carbon and iron/activated carbon nanocomposites in fixed bed column: experimental and modelling study

In this work, iron nanoparticles were impregnated onto a commercialactivated carbon surface to produce a novel adsorbent called iron-activated carbonnanocomposite (I-AC). Commercial activated carbon (CAC) and I-AC were usedfor vanadium separation in a fixed-bed column. The effects of various operatingparameters such as inlet vanadium ion concentration, adsorbent dose and volumetricflow rate on vanadium separation performance of CAC were investigated. Theperformance of both adsorbents was compared in three adsorption/desorptioncycles. The experimental breakthrough curves of vanadium ions in the fixed-bedcolumn were modeled using the film-pore-surface diffusion model (FPSDM). Thefour mass transfer parameters characterizing this model, namely the external masstransfercoefficient (kf), pore and surface diffusion coefficients (Dp and Ds), andaxial dispersion coefficient (DL) were evaluated through the model. Modelling andexperimental results showed that the I-AC nanocomposite has a better performancefor vanadium separation in comparison to AC. Sensitivity analysis on the FPSDMshowed that the pore and surface diffusion, external mass transfer and axial dispersionplay a significant role in vanadium separation using the I-AC. On the otherhand, surface diffusion resulted to be relatively less important when CAC was used.