Bangari Raghubeer S, Singh Arun K, Namsani Sadanandam, Singh Jayant K, Sinha Niraj
ACS Appl Mater Interfaces. 2019 May 29;11(21):19017-19028. doi: 10.1021/acsami.8b22401. Epub 2019 May 14.
It is widely known that the existence of arsenic (As) in water negatively affects humans and the environment. We report the synthesis, characterization, and application of boron nitride nanosheets (BNNSs) and FeO-functionalized BNNS (BNNS-FeO) nanocomposite for removal of As(V) ions from aqueous systems. The morphology, surface properties, and compositions of synthesized nanomaterials were examined using scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, surface area analysis, zero-point charge, and magnetic moment determination. The BNNS-FeO nanocomposites have a specific surface area of 119 m g and a high saturation magnetization of 49.19 emu g. Due to this strong magnetic property at room temperature, BNNS-FeO can be easily separated in solution by applying an external magnetic field. From the activation energies, it was found that the adsorption of As(V) ions on BNNSs and BNNS-FeO was due to physical and chemical adsorption, respectively. The maximum adsorption capacity of BNNS-FeO nanocomposite for As(V) ions has been found to be 26.3 mg g, which is 5 times higher than that of unmodified BNNSs (5.3 mg g). This closely matches density functional theory simulations, where it is found that binding energies between BNNS-FeO nanocomposite and As(OH) are 5 times higher than those between BNNSs and As(OH), implying 5 times higher adsorption capacity of BNNS-FeO nanocomposite than unmodified BNNSs. More importantly, it was observed that the synthesized BNNS-FeO nanocomposite could reduce As(V) ion concentration from 856 ppb in a solution to below 10 ppb (>98.83% removal), which is the permissible limit according to World Health Organization recommendations. Finally, the synthesized adsorbent showed both separation and regeneration properties. These findings demonstrate the potential of BNNS-FeO nanocomposite for commercial application in separation of As(V) ions from potable and waste water streams.
众所周知，水中砷（As）的存在会对人类和环境产生负面影响。我们报告了用于从水体系中去除As（V）离子的氮化硼纳米片（BNNSs）和FeO功能化的BNNS（BNNS-FeO）纳米复合材料的合成、表征及应用。使用扫描电子显微镜、透射电子显微镜、X射线粉末衍射、表面积分析、零电荷点和磁矩测定来检查合成纳米材料的形态、表面性质和组成。BNNS-FeO纳米复合材料的比表面积为119 m²/g，饱和磁化强度高达49.19 emu/g。由于在室温下具有这种强磁性，通过施加外部磁场，BNNS-FeO可以在溶液中轻松分离。从活化能可知，As（V）离子在BNNSs和BNNS-FeO上的吸附分别归因于物理吸附和化学吸附。已发现BNNS-FeO纳米复合材料对As（V）离子的最大吸附容量为26.3 mg/g，这比未改性的BNNSs（5.3 mg/g）高5倍。这与密度泛函理论模拟结果密切匹配，其中发现BNNS-FeO纳米复合材料与As（OH）之间的结合能比BNNSs与As（OH）之间的结合能高5倍，这意味着BNNS-FeO纳米复合材料的吸附容量比未改性的BNNSs高5倍。更重要的是，观察到合成的BNNS-FeO纳米复合材料可将溶液中As（V）离子浓度从856 ppb降低至10 ppb以下（去除率>98.83%），这是世界卫生组织建议的允许限值。最后，合成的吸附剂显示出分离和再生性能。这些发现证明了BNNS-FeO纳米复合材料在从饮用水和废水流中分离As（V）离子方面的商业应用潜力。
