Nanoenvirology Research Group, Department of Civil and Environmental Engineering, North Dakota State University, Fargo, ND, 58105, USA.
Advanced Materials Processing and Analysis Center (AMPAC), Nanoscience and Technology Center (NSTC), Materials Science and Engineering (MSE), University of Central Florida, Orlando, USA.
Chemosphere. 2020 Aug;253:126702. doi: 10.1016/j.chemosphere.2020.126702. Epub 2020 Apr 8.
Iron (Fe)-based adsorbents have been promoted for aqueous arsenic adsorption because of their low cost and potential ease of scale-up in production. However, their field application is, so far, limited because of their low Fe use efficiency (i.e., not all available Fe is used), slow adsorption kinetics, and low adsorption capacity. In this study, we synthesized graphene oxide iron nanohybrid (GFeN) by decorating iron/iron oxide (Fe/FeO) core-shell structured iron nanoparticles (FeNPs) on the surface of graphene oxide (GO) via a sol-gel process. The deposition of FeNPs on GO for the nanohybrid (GFeN) improves Fe use efficiency and arsenic mobility in the nanohybrid, thereby improving the arsenic removal capacity and kinetics. We achieved removal capacities of 306 mg/g for As(III) and 431 mg/g for As(V) using GFeN. Rapid reduction (>99% in <10 min) of As(III) and As(V) (initial concentration, C = 100 μg/L) was achieved with the nanohybrid (250 mg/L). There were no significant interferences by the coexisting anions and organic matters at environmentally relevant concentrations. Based on the experimental data, we have proposed that both electrostatic interaction and surface complexation contributed to ultra-high arsenic removal by GFeN. The GO sheets acted as the reservoirs for the electrons released during surface corrosion of the FeNPs and the electrons were transferred back to the FeNPs to rejuvenate the oxidized surface. The rejuvenated FeNP surface layer helped in additional arsenic removal.
铁（Fe）基吸附剂因其成本低且在生产中易于扩大规模而被推广用于水中砷的吸附。然而，迄今为止，由于其铁利用率低（即并非所有可用的铁都被利用）、吸附动力学缓慢和吸附容量低，其现场应用受到限制。在本研究中，我们通过溶胶-凝胶工艺在氧化石墨烯（GO）表面上修饰铁/氧化铁（Fe/FeO）核壳结构的铁纳米粒子（FeNPs），合成了氧化石墨烯铁纳米杂化物（GFeN）。FeNPs 在 GO 上的沉积提高了纳米杂化物中的铁利用率和砷迁移率，从而提高了砷的去除能力和动力学。我们使用 GFeN 实现了 306mg/g 的 As(III)去除容量和 431mg/g 的 As(V)去除容量。纳米杂化物（250mg/L）可在<10min 内快速还原（>99%）As(III)和 As(V)（初始浓度，C=100μg/L）。在环境相关浓度下，共存的阴离子和有机物没有对其造成显著干扰。根据实验数据，我们提出 GFeN 对超高砷去除的贡献既有静电相互作用又有表面络合作用。GO 片作为 FeNPs 表面腐蚀过程中释放的电子的储库，电子被转移回 FeNPs 以再生氧化表面。再生的 FeNP 表面层有助于进一步去除砷。
