Strong adsorption of arsenic species by amorphous zirconium oxide nanoparticles

A novel oxide adsorbent of amorphous zirconium oxide (am-ZrO ₂) nanoparticles was synthesized by a simple hydrothermal process for effective arsenic removal from aqueous environment. Due to their high specific surface area (327.1m ²/g), large mesopore volume (0.68cm ³/g), and the presence of high affinity surface hydroxyl groups, am-ZrO ₂ nanoparticles demonstrated exceptional adsorption performance on both As(III) (arsenite) and As(V) (arsenate) without pre-treatment at near neutral condition. At pH∼7, the adsorption kinetic is fast and the adsorption capacity is high (over 83mg/g for As(III) and over 32.4mg/g for As(V), respectively). Under low equilibrium arsenic concentrations (C _e at 0.01mg/L, the maximum contaminant level (MCL) for arsenic in drinking water), the amount of arsenic adsorbed by am-ZrO ₂ nanoparticles is over 0.92mg/g for As(III) and over 5.2mg/g for As(V), respectively. The adsorption mechanism of arsenic species onto am-ZrO ₂ nanoparticles was found to follow the inner-sphere complex mechanism. Testing with arsenic contaminated natural lake water confirmed the effectiveness of these am-ZrO ₂ nanoparticles in removing arsenic from natural water. The immobilized am-ZrO ₂ nanoparticles on glass fiber cloth demonstrated an even better arsenic removal performance than dispersed am-ZrO ₂ nanoparticles in water, paving the way for their potential applications in water treatment facility to treat arsenic contaminated water body without pre-treatment.