Zhang Q L, Gao Nai-Yun, Lin Y C, Xu Bin, Le Lin-sheng
State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, China.
Water Environ Res. 2007 Aug;79(8):931-6. doi: 10.2175/106143007x156727.
Removal of arsenic(V) from aqueous solutions was evaluated with the following three different sorption materials: coal-based activated carbon 12 x 40 (activated carbon), iron(II) oxide (FeO)/activated carbon-H, and iron oxide. The apparent characteristics and physical chemistry performances of these adsorbents were investigated by X-ray diffraction, nitrogen adsorption, and scanning electronic microscope. Also, batch experiments for arsenic removal were performed, and the effects of pH value on arsenic(V) removal were studied. The results suggest that the main phases of the iron oxide surface are magnetite, maghemite, hematite, and goethite; fine and uniform iron oxide particles can cover activated carbon surfaces and affect the surface area or pore structures of activated carbon; adsorption kinetics obey a pseudo-first-order rate equation; and adsorption capacities of adsorbents are affected by the values of pH. The optimum value of pH for iron oxide lies in a narrow range between 4.0 and 5.5, and arsenic(V) removal by FeO/activated carbon-H is ideal and stable in the pH range 3 to 7, while activated carbon has the lowest adsorption capacity in the entire pH range. Also, the adsorption characteristics of FeO/activated carbon-H composites and virgin activated carbon match well the Langmuir adsorption model, while those of iron oxide fit well the Freundlich adsorption model.
煤基活性炭12×40（活性炭）、氧化亚铁（FeO）/活性炭-H和氧化铁。通过X射线衍射、氮气吸附和扫描电子显微镜研究了这些吸附剂的表观特征和物理化学性能。此外，进行了去除砷的批量实验，并研究了pH值对五价砷去除效果的影响。结果表明，氧化铁表面的主要相为磁铁矿、磁赤铁矿、赤铁矿和针铁矿；细小且均匀的氧化铁颗粒可以覆盖活性炭表面并影响活性炭的表面积或孔隙结构；吸附动力学符合准一级速率方程；吸附剂的吸附容量受pH值的影响。氧化铁的最佳pH值在4.0至5.5的狭窄范围内，FeO/活性炭-H在pH值为3至7的范围内对五价砷的去除效果理想且稳定，而活性炭在整个pH范围内的吸附容量最低。此外，FeO/活性炭-H复合材料和原始活性炭的吸附特性与朗缪尔吸附模型匹配良好，而氧化铁的吸附特性与弗伦德利希吸附模型匹配良好。
