One step preparation of ZnFe₂O₄/Zn₅(OH)₆(CO₃)₂ nanocomposite with improved As(V) removal capacity

Novel adsorbents consisting of ZnFe₂O₄/Zn₅(OH)₆(CO₃)₂ (hydrozincite) nanocomposite materials were studied for efficient As(V) removal from water. Nanocomposites were synthesized by the co-precipitation of Zn and Fe salts in alkaline conditions. Depending on the Zn/Fe molar ratio, a variety of materials was produced with different ZnFe₂O₄/Zn₅(OH)₆(CO₃)₂ contents. The adsorbent’s efficiency for As(V) removal was enhanced proportionally to the percentage of Zn₅(OH)₆(CO₃)₂ content. The nanocomposite with 74 ± 7 wt% of Zn₅(OH)₆(CO₃)₂ provided a capacity of 18.4 μg As(V)/mg for residual concentration of 10 μg/L (pH 7) which is over twice that of an iron oxy-hydroxide prepared under similar conditions.