零价铁(ZVI)和改性ZVI已被广泛研究用于地下水修复。然而,ZVI基粉末由于其低的水渗透性和使用率而难以直接用作可渗透的反应性屏障(PRB)材料。在这项研究中,通过球磨制备了硫化铁-铜双金属,这是环境友好的,没有二次污染。确定了去除Cr(VI)的硫化铁铜双金属的最佳制备参数(Cu/Fe比(w/w),0.018;FeS/Fe比(w/w),0.1213;球磨速度,450转/分;球磨时间,5h).通过烧结硫化铁-铜双金属的混合物制备复合渗透材料,污泥,和高岭土。制备复合渗透材料的参数包括污泥含量和粒径,优化了烧结时间,是60%,60-75目,和4小时,分别。通过SEM-EDS对最佳复合透水材料进行了表征,XRD,和FTIR。结果表明,制备参数会影响复合透水材料的水力传导率和硬度。污泥含量高,小颗粒大小,适当的烧结时间使复合渗透材料具有较高的渗透性,有利于Cr(VI)的去除。主要的Cr(VI)去除机制是还原,反应遵循伪一级动力学。相反,污泥含量低,粒径大,烧结时间长导致复合透水材料的渗透性低。铬酸盐的去除主要是通过化学吸附遵循伪二级动力学。最佳复合透水材料的水力传导率和硬度分别达到1.732cm/s和50。柱实验结果表明,其Cr(VI)去除能力为0.54mg/g,在pH5、7和9时分别为0.39mg/g和0.29mg/g。在酸性和碱性条件下,复合渗透材料表面的Cr(VI)与Cr(III)的比例相似。本研究将为现场应用提供一种有效的反应性材料PRB。
Zero-valent iron (ZVI) and modified ZVI have been investigated extensively for groundwater remediation. However, ZVI based powder was difficult to be applied directly as permeable reactive barrier (PRB) materials due to their low water permeability and usage rate. In this
study, sulfide iron-copper bimetal was prepared by ball milling, which is environment-friendly without second contamination. The optimal preparation parameters of sulfide iron-copper bimetal for Cr(VI) removal were determined (Cu/Fe ratio (w/w), 0.018; FeS/Fe ratio (w/w), 0.1213; ball milling speed, 450 rpm; ball milling time, 5 h). A composite permeable material was prepared by sintering a mixture of sulfide iron-copper bimetal, sludge, and kaolin. The parameters for composite permeable material preparation including sludge content and particle size, and sintering time were optimized, which were 60%, 60-75 mesh, and 4 h, respectively. The optimal composite permeable material was characterized by SEM-EDS, XRD, and FTIR. The results demonstrated preparation parameters can affect the hydraulic conductivity and hardness of composite permeable material. High sludge content, small particles size, and moderate sintering time resulted in high permeability of composite permeable material and were beneficial for Cr(VI) removal. The dominant Cr(VI) removal mechanism was reduction, and the reaction followed pseudo-first order kinetics. Conversely, low sludge content and large particle size, and long sintering time lead to low permeability of composite permeable material. Chromate removal was mainly by chemisorption following pseudo-second order kinetics. The hydraulic conductivity and hardness of the optimal composite permeable material achieved 1.732 cm/s and 50, respectively. The results of column experiments indicated that its Cr(VI) removal capacity was 0.54 mg/g, 0.39 mg/g and 0.29 mg/g at pH 5, 7 and 9, respectively. The ratio of Cr(VI) to Cr(III) on composite permeable material surface was similar under acidic and alkaline conditions. This
study will provide an effective reactive material of PRB for field application.