In addition to being used as an energy source, coal also has significant potential for other, more sustainable uses including water treatment. In this study, we present a simple approach to treat water that was produced during oil production and contained a total dissolved solids (TDS) content of over 150 g/L using Powder River Basin (PRB) coal. PRB coal used as packing material in a flow-through column effectively removed 60%–80% of the cations and anions simultaneously. Additionally, 71%–92% of the total organic carbon in the produced water was removed as was all of the total suspended solids. The removal mechanisms of both cations and anions were investigated. Cations were removed by ion exchange with protons from oxygen-containing functional groups such as carboxylic and phenolic hydroxyl groups. Anions, mainly Cl⁻¹, appeared to be removed through either the formation of resonance structures as a result of delocalization of electrons within coal molecules or through ion–π interactions. We propose that coal is a “pseudo-amphoteric” exchange material that can remove cations and anions simultaneously by exchanging ions with both ionized and non-ionized acids that are ubiquitous in coal structure or resonance effect.

Graphical abstract

中文翻译：

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使用粉河盆地煤从采出水中去除离子

除了用作能源之外，煤炭还具有用于其他更可持续用途的巨大潜力，包括水处理。在这项研究中，我们提出了一种使用粉河盆地 (PRB) 煤处理石油生产过程中产生的总溶解固体 (TDS) 含量超过 150 g/L 的水的简单方法。在流通塔中用作填料的 PRB 煤有效地同时去除了 60%–80% 的阳离子和阴离子。此外，采出水中 71%–92% 的总有机碳与所有总悬浮固体一样被去除。研究了阳离子和阴离子的去除机制。通过与含氧官能团（如羧基和酚羟基）的质子进行离子交换来去除阳离子。阴离子，主要是 Cl ^-1，似乎通过形成共振结构（由于煤分子内的电子离域或通过离子-π相互作用）而被去除。我们提出煤是一种“伪两性”交换材料，它可以通过与煤结构或共振效应中普遍存在的离子化和非离子化酸交换离子来同时去除阳离子和阴离子。

图形概要