Exceptional arsenic adsorption performance of hydrous cerium oxide nanoparticles: Part A. Adsorption capacity and mechanism

Hydrous cerium oxide (HCO) nanoparticles were synthesized by a simple precipitation process, and their arsenic adsorption performances were investigated. Due to their high specific surface area (198 m2/g) and the presence of high affinity surface hydroxyl groups, HCO nanoparticles demonstrated exceptional adsorption properties in terms of adsorption capacity and kinetics on both As(III) and As(V). At neutral pH, the arsenic adsorption capacity of HCO reached over 170 mg/g for As(III) and 107 mg/g for As(V). Even at very low equilibrium arsenic concentrations, the amount of As(III) and As(V) adsorbed by HCO nanoparticles was still over 13 mg/g at 10 μg/L and over 40 mg/g at 50 μg/L, which are higher than the arsenic adsorption capacity for most commercial adsorbents. Over a wide pH range from 3 to 11, HCO nanoparticles could readily remove As(III) by adsorption, which was not observed previously on other arsenic adsorbents. Such exceptional arsenic adsorption properties by HCO nanoparticles were shown to derive from the strong inner-sphere complexion.

Figure optionsDownload as PowerPoint slideHighlights
► Hydrous cerium oxide nanoparticles were synthesized by a simple precipitation process.
► HCO nanoparticles demonstrated exceptional arsenic adsorption properties.
► HCO nanoparticles could readily remove As(III) by adsorption from pH 3 to 11.
► The arsenic adsorption mechanism follows the inner-sphere complex mechanism.