Preparation and characterization of alumina-supported iron nanoparticles and its application for the removal of aqueous Cu2+ ions

A composite sorbent of iron nanoparticles and alumina (Al–nZVI) was prepared and applied in the removal of Cu2+ ions from aqueous solutions. Alumina was introduced in a solution of Fe2+ ions, which were then reduced to metallic iron nanoparticles using borohydride ions. The characterization results showed that iron nanoparticles were partially dispersed on alumina surface, with their diameter being in the range 10–80 nm. The uptake experiments were performed at initial Cu2+ concentrations ranging from 10.0 to 500.0 mg/L. The experiments investigated the effects of initial concentration, contact time, and repetitive usage of the Al–nZVI on the extent of removal of Cu2+ ions. The composite sorbent demonstrated fast uptake, and its fixation capacity was 1.50 mmol/g (95.3 mg/g), which is well above that of pure alumina (0.32 mmol/g; 20.3 mg/g).