Accumulation of Vanadium by Nanoscale Zero-Valent Iron Supported by Activated Carbon under Simulation Water Conditions: A Batch Study

Vanadium (V(V)) removal from simulation water (SW) was successfully accomplished using nanoscale zero-valent iron that was immobilized by activated carbon (NZVI/AC) which was used as an adsorbent. We investigated the effects of different parameters on V(V) removal, such as pH, dissolved oxygen (DO), common ions and adsorption kinetics for SW. The intraparticle diffusion model fits this study well (R-2 > 0.9) according to the results of the kinetics investigation which showed that the adsorption of vanadium by NZVI/AC was rapid in the first 12 h and that equilibrium was reached in about 72 h. The amount of V(V) that was removed from the solution increased when it was subjected to pH 2 to pH 8, and this decreased after pH 8. While the effects of other anions and humic acid were negligible, the elimination of V(V) was significantly reduced by using phosphate and silicate. Fe2+ and Al3+, two common metal cations, improved the V(V) adsorption. High oxygen levels impeded the vanadium elimination, while anoxic conditions encouraged it. Elution with 0.1 M NaOH can be used to renew NZVI/AC in an efficient manner.

Automated summary

In this study, vanadium (V(V)) was successfully removed from simulation water using nanoscale zero-valent iron immobilized by activated carbon (NZVI/AC) as an adsorbent. The effects of pH, dissolved oxygen, common ions, and adsorption kinetics on V(V) removal were investigated. The intraparticle diffusion model was found to fit the kinetics data well, indicating rapid adsorption of vanadium by NZVI/AC within the first 12 hours and equilibrium reached in approximately 72 hours. The removal efficiency of V(V) increased from pH 2 to pH 8 and decreased after pH 8. Phosphate and silicate significantly reduced the elimination of V(V), while the effects of other anions and humic acid were negligible. Fe2+ and Al3+ cations improved V(V) adsorption. High oxygen levels impeded vanadium elimination, while anoxic conditions encouraged it. Elution with 0.1 M NaOH was found to be an efficient method for renewing NZVI/AC.