Modeling the Kinetics of Hydrogen Formation by Zerovalent Iron: Effects of Sulfidation on Micro- and Nano-Scale Particles.
Modeling the Kinetics of Hydrogen Formation by Zerovalent Iron: Effects of Sulfidation on Micro- and Nano-Scale Particles.
复制标题
DOI：
10.1021/acs.est.8b04436
复制
发表时间：
2018-11
影响因子：
11.4
通讯作者：
Hejie Qin;Xiaohong Guan;J. Bandstra;Richard L. Johnson;Paul G Tratnyek
中科院分区：
文献类型：
--
作者：
Hejie Qin;Xiaohong Guan;J. Bandstra;Richard L. Johnson;Paul G Tratnyek
由FeO还原H2O产生H2的析氢反应（HER）是控制含有零价铁（ZVI）的环境系统中的反应性的最基本的过程之一。为了开发一个全面的动力学模型，这个过程中，一个大的和高分辨率的数据集HER使用五种类型的ZVI预处理酸洗和/或硫化（在pH 7 HEPES缓冲液）进行测量。使用同时应用于整个数据集的非线性回归分析，将数据拟合到四个替代动力学模型，这允许在多个实验中全局处理一些模型参数。优选的模型使用两个独立的反应阶段来匹配大多数HER数据的两阶段特征，其中每个阶段的速率常数（k）由铁类型全局拟合，并且相量（S）拟合为完全局部（独立）参数。第一，较快的阶段归因于反应性矿物中间体（RMI）相，如Fe（OH）2，其可在预平衡期间在所有实验中形成，但迅速消耗，留下第二，较慢的HER阶段，这是由于Fe 0的反应。除了提供一个确定性的模型来解释HER的动力学ZVI在很宽的范围内的条件下，结果提供了一个改进的定量基础比较硫化对ZVI的影响。
The hydrogen evolution reaction (HER) that generates H2 from the reduction of H2O by Fe0 is among the most fundamental of the processes that control reactivity in environmental systems containing zerovalent iron (ZVI). To develop a comprehensive kinetic model for this process, a large and high-resolution data set for HER was measured using five types of ZVI pretreated by acid-washing and/or sulfidation (in pH 7 HEPES buffer). The data were fit to four alternative kinetic models using nonlinear regression analysis applied to the whole data set simultaneously, which allowed some model parameters to be treated globally across multiple experiments. The preferred model uses two independent reactive phases to match the two-stage character of most HER data, with rate constants ( k's) for each phase fitted globally by iron type and phase quantities ( S's) fitted as fully local (independent) parameters. The first, faster stage was attributed to a reactive mineral intermediate (RMI) phase like Fe(OH)2, which may form in all experiments during preequilibration, but is rapidly consumed, leaving the second, slower stage of HER, which is due to reaction of Fe0. In addition to providing a deterministic model to explain the kinetics of HER by ZVI over a wide range of conditions, the results provide an improved quantitative basis for comparing the effects of sulfidation on ZVI.