College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, 030024, P.R. China.
Sci Rep. 2020 Apr 30;10(1):7382. doi: 10.1038/s41598-020-64476-5.
Green iron nanoparticles (G-nZVI) were synthesized in situ by adding grape-seed extracts and Fe solution simultaneously. The performances for the removal of Cr(VI) were compared in a homogeneous system by original G-nZVI (in suspension) with in a heterogeneous system by treated G-nZVI. The characterization of TEM, SEM, XRD, FTIR and XPS show that G-nZVI is the formation of Fe°-iron oxide core-shell nanoparticles with organic matters in the extracts as capping/stabilizing agents. The same excellent performances on the removal of Cr(VI) were observed in the both systems and the adsorption capacity was from 78.3 to 166.7 mg (Cr)·g (Fe) with the increase of initial Fe concentrations. The pseudo second-order model described the adsorption process excellently and both pseudo first-order and pseudo second-order models fit the reduction process well. It illustrated that the reaction included prompt adsorption and simultaneous redox process. Moreover, the results of thermodynamics study (ΔG° < 0, ΔH° > 0, ΔS° > 0) revealed that the adsorption was a spontaneous and endothermic process. It is obvious that the systhesis of original G-nZVI in the homogeneous system is more simple, rapid, cost-effective and suitable for in situ uses. It holds a great potential for remediation of soil and water.
绿色铁纳米粒子（G-nZVI）是通过同时添加葡萄籽提取物和 Fe 溶液原位合成的。通过原始 G-nZVI（悬浮液）在均相体系中和通过处理过的 G-nZVI 在非均相体系中比较了去除 Cr(VI)的性能。TEM、SEM、XRD、FTIR 和 XPS 的表征表明，G-nZVI 是 Fe°-氧化铁核壳纳米粒子的形成，提取物中的有机物作为封端/稳定剂。在这两种体系中都观察到对 Cr(VI)去除的相同优异性能，并且吸附容量随着初始 Fe 浓度的增加从 78.3 到 166.7 mg（Cr）·g（Fe）。准二级模型很好地描述了吸附过程，准一级和准二级模型都很好地拟合了还原过程。这表明反应包括快速吸附和同时的氧化还原过程。此外，热力学研究（ΔG°<0，ΔH°>0，ΔS°>0）的结果表明吸附是自发和吸热的过程。显然，在均相体系中原位合成原始 G-nZVI 更简单、快速、经济高效，适合原位使用。它在土壤和水的修复中具有很大的潜力。
