Department of Environmental Nano-materials, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China; National Engineering Laboratory for VOCs Pollution Control Materials & Technology, University of Chinese Academy of Sciences, Beijing, 101408, PR China.
Department of Environmental Nano-materials, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China.
Chemosphere. 2019 Jul;226:834-840. doi: 10.1016/j.chemosphere.2019.03.194. Epub 2019 Apr 1.
In the environment, antimony as a priority control pollutant is mainly associated with Fe- or Mn- related minerals. In this work, acid birnessite (AB) doped with iron was synthesized as the artificial mineral to study the adsorption and oxidation of antimony. As compared to the pristine birnessite, Fe-doping birnessites show a markedly enhanced removal efficiency for both Sb(III) and Sb(V), where 10% Fe exhibited an excellent adsorption capacity of 759 mg/g Sb(III). The removal of Sb(III) clearly underwent a novel kinetic process of adsorption-desorption- (re-adsorption). By monitoring the kinetics with XRD, XPS, and IR, it is demonstrated that the three-stage kinetics were attributed to the strong interaction between Sb(III) and birnessite, including Sb(III) oxidation, followed by destruction of birnessite and then phase transformation into vernadite. Furthermore, the increase of iron content doped into birnessite enhanced the rate of its phase transition, which led to an increased adsorption of the oxidized antimony on the surface of vernadite by substituting iron and manganese associated with hydroxyl group. This work suggested that the strong interactions between heavy metal ions and mineral particles, more than adsorption, are critical to the transformation, mobility and biotoxicity of antimony in nature.
在环境中，锑作为优先控制的污染物，主要与铁或锰相关的矿物质有关。在这项工作中，合成了掺杂铁的酸锰矿作为人工矿物，以研究锑的吸附和氧化。与原始锰矿相比，掺杂铁的锰矿对 Sb(III) 和 Sb(V) 的去除效率明显提高，其中 10%的铁表现出优异的 Sb(III)吸附容量为 759mg/g。Sb(III)的去除明显经历了吸附-解吸-（再吸附）的新动力学过程。通过 XRD、XPS 和 IR 监测动力学，证明三阶动力学归因于 Sb(III)与锰矿之间的强相互作用，包括 Sb(III)的氧化，随后是锰矿的破坏，然后转化为纤铁矿。此外，掺杂到锰矿中的铁含量的增加增强了其相变的速率，这导致氧化的锑通过取代与羟基相关的铁和锰在纤铁矿表面上的吸附增加。这项工作表明，重金属离子与矿物颗粒之间的强相互作用，而不是吸附，对锑在自然界中的转化、迁移和生物毒性至关重要。
