Synthesis and evaluation of iron-containing ordered mesoporous carbon (FeOMC) for arsenic adsorption

Recent progress in nanotechnology has resulted in numerous nanoscale structures and devices with exceptional chemical, physical and biological properties and functions. In this study, we developed an ordered nano-structured adsorbent, iron-containing ordered mesoporous carbon (FeOMC), for arsenic adsorption from water. FeOMC preparation involved in synthesis of ordered silica template SBA-15, in situ polymerization of mono acrylic acid (AA) in the silica template followed by carbonization and template removal to obtain ordered mesoporous carbon (OMC), and iron impregnation. Sample characterizations by transmission electron microcopy, X-ray diffraction, and nitrogen adsorption indicated that the prepared OMC and FeOMC had an ordered mesoporous structure with high specific surface area of 607 m2/g and 466 m2/g, respectively. Arsenic adsorption experiments showed that the maximum arsenic adsorption was primarily controlled by the amount of iron impregnated, and the molar ratio of iron and the maximum amount of arsenate adsorption was 5.53–7.97. The optimal pH values for adsorption depended on arsenic species: at an initial concentration of 9.98 mg/L arsenic, the optimal pH range was 3.0–7.0 for arsenate removal and 6.0–9.5 for arsenite. The rate of arsenic removal by FeOMC was high, suggesting that it could be potentially applied in point-of-use systems where fast adsorption kinetics is needed.