National Energy Technology Laboratory, 626 Cochrans Mill Rd, P.O. Box 10940, Pittsburgh, PA 15236-0940, USA; Oak Ridge Institute for Science and Education, P.O. Box 117, Oak Ridge, TN 37831-0117, USA.
National Energy Technology Laboratory, 626 Cochrans Mill Rd, P.O. Box 10940, Pittsburgh, PA 15236-0940, USA; NETL Support Contractor, 626 Cochrans Mill Rd, P.O. Box 10940, Pittsburgh, PA 15236-0940, USA.
J Chromatogr A. 2022 Apr 12;1668:462924. doi: 10.1016/j.chroma.2022.462924. Epub 2022 Feb 28.
This study outlines the development and subsequent validation of a method using chelation ion chromatography (CIC) pretreatment followed by traditional ion chromatography (IC) and post column UV/vis detection to measure transition metals in fossil fuel wastewaters, such as oil & gas (O&G) brines and coal mine drainage (CMD) waters. Measurement of transition metals is often an important characterization step in the research of environmental and energy systems. IC represents one way to measure these metals with the advantages of being versatile, simple and relatively low cost compared to other analytical methods. However, high concentrations of alkali and alkaline earth metals present in fossil fuel wastewaters will decrease IC detectability of transition metals in these waters. In this study, a CIC method was developed for the analysis of transition metal ions (Fe, Cu, Ni, Zn, Co, Mn, and Fe) in fossil fuel associated wastewaters such as Appalachian CMD and O&G wastewaters from the Permian and Bakken shale basins in the United States. CIC system incorporated an on-line chelator column (e.g., the MetPac CC-1) with high selectivity for transition metals over alkali and alkaline earth metals for salt matrix removal prior to transition metal separation and detection. Additional method developments also included acidifying all samples to 2% v/v HCl and using gradient elution rather than isocratic. The recoverability of transition metals in simple salt solutions commonly found in CMD and brine samples (e.g. NaCl, NaSO, CaCl) using CIC was evaluated and compared to that using traditional IC. Our results found that the CIC system significantly improved transition metal recoveries for samples in 10,000 mg/L CaCl matrix, reaching 87%-108% recovery for all analytes, as opposed to 2-323% recovery in traditional IC. The limits of detection in this study achieved 10.09-161.2 μg/L, comparable to reported values in similar IC studies. The developed method was also verified with certified water samples, resulting in 89%-111% recoveries in samples with higher analyte concentrations (i.e. >4x the LoDs). The developed method achieved 87%-112% recoveries for most analytes in CMD samples and 72%-138% recoveries for Bakken shale samples, relative to ICP-MS values. Overall, the current IC method can be a very good screening tool for fast and cheap analysis for transition metals at mg/L level, to facilitate selection of samples for more detailed ICP-MS analysis.
本研究概述了一种方法的开发和随后的验证，该方法使用螯合离子色谱 (CIC) 预处理，然后进行传统的离子色谱 (IC) 和柱后 UV/可见检测，以测量化石燃料废水中的过渡金属，如石油和天然气 (O&G) 盐水和煤矿排水 (CMD) 水。过渡金属的测量通常是环境和能源系统研究中的一个重要特征步骤。IC 是测量这些金属的一种方法，与其他分析方法相比，它具有多功能、简单和相对低成本的优点。然而，化石燃料废水中存在的高浓度碱金属和碱土金属会降低 IC 对这些水中过渡金属的检测能力。在本研究中，开发了一种 CIC 方法，用于分析与化石燃料相关的废水中的过渡金属离子（Fe、Cu、Ni、Zn、Co、Mn 和 Fe），如美国阿巴拉契亚 CMD 和二叠纪和巴肯页岩盆地的 O&G 废水。CIC 系统采用在线螯合柱（例如，MetPac CC-1），对过渡金属具有高选择性，对碱金属和碱土金属具有高选择性，用于在过渡金属分离和检测之前去除盐基质。此外，方法开发还包括将所有样品酸化至 2% v/v HCl 并使用梯度洗脱而不是等度洗脱。使用 CIC 评估了在 CMD 和盐水样品中常见的简单盐溶液（例如 NaCl、NaSO 和 CaCl）中过渡金属的回收率，并与传统 IC 进行了比较。我们的结果发现，CIC 系统显著提高了 10000 mg/L CaCl 基质样品中过渡金属的回收率，所有分析物的回收率达到 87%-108%，而传统 IC 的回收率为 2-323%。本研究的检出限达到 10.09-161.2 μg/L，与类似 IC 研究中的报告值相当。该方法还通过认证水样进行了验证，在分析物浓度较高（即 >4 倍检出限）的样品中，回收率为 89%-111%。该方法在 CMD 样品中对大多数分析物的回收率为 87%-112%，在 Bakken 页岩样品中的回收率为 72%-138%，与 ICP-MS 值相对应。总体而言，目前的 IC 方法可以作为一种非常好的筛选工具，用于快速、廉价地分析 mg/L 水平的过渡金属，以促进选择更详细的 ICP-MS 分析的样品。
