Meissner Michael S, Nguyen Vy H T, Bousrih Imen, Le Van T C, Frickenstein Alex, Le Giang V, Bui Ngoc T
School of Chemical, Biological, and Materials Engineering, The University of Oklahoma, Norman, OK, United States.
Stephenson School of Biomedical Engineering, Norman, OK, United States.
Front Chem. 2023 Sep 8;11:1225843. doi: 10.3389/fchem.2023.1225843. eCollection 2023.
Temperature-swing solvent extraction (TSSE) is a cost-effective, simple, versatile, and industry-ready technology platform capable of desalinating hypersaline brines toward zero liquid discharge. In this work, we demonstrate the potential of TSSE in the effective removal of selenium oxyanions and traces of mercury with the coexistence of high contents of chloride and sulfate often encountered in flue gas desulfurization wastewater streams. We compare the rejection performance of the two common solvents broadly used for TSSE, decanoic acid (DA) and diisopropylamine (DPA), and correlate those with the solvent physicochemical properties (e.g., dielectric constant, polarity, molecular bulkiness, and hydrophobicity) and ionic properties (e.g., hydrated radii and H-bonding). The results show that TSSE can remove >99.5% of selenium oxyanions and 96%-99.6% of mercury traces coexisting with sulfate (at a sixfold Se concentration) and chloride (at a 400-fold Se concentration) in a synthetic wastewater stream. Compared to diisopropylamine, decanoic acid is more effective in rejecting ions for all cases, ranging from a simple binary system to more complex multicomponent systems with highly varied ionic concentrations. Furthermore, the H-bonding interaction with water and the hydrated radii of the oxyanions (i.e., selenate vs selenite) along with the hindrance effects caused by the molecular bulkiness and hydrophobicity (or lipophilicity) of the solvents play important roles in the favorable rejection of TSSE. This study shows that TSSE might provide a technological solution with a high deionization potential for the industry in complying with the Environmental Protection Agency regulations for discharge streams from coal-fired power facilities.
变温溶剂萃取（TSSE）是一种经济高效、简单通用且适用于工业的技术平台，能够对高盐卤水进行脱盐处理，实现零液体排放。在本研究中，我们展示了TSSE在有效去除硒氧阴离子和痕量汞方面的潜力，这些物质共存于烟气脱硫废水流中常见的高含量氯离子和硫酸根离子环境中。我们比较了TSSE中广泛使用的两种常见溶剂——癸酸（DA）和二异丙胺（DPA）的截留性能，并将其与溶剂的物理化学性质（如介电常数、极性、分子体积和疏水性）以及离子性质（如水合半径和氢键）相关联。结果表明，在合成废水流中，TSSE能够去除>99.5%的硒氧阴离子以及96% - 99.6%与硫酸根（硒浓度的六倍）和氯离子（硒浓度的400倍）共存的痕量汞。与二异丙胺相比，癸酸在所有情况下对离子的截留效果都更好，范围从简单的二元体系到离子浓度变化很大的更复杂多组分体系。此外，溶剂与水的氢键相互作用、氧阴离子（即硒酸根与亚硒酸根）的水合半径，以及溶剂的分子体积和疏水性（或亲脂性）所造成的阻碍效应，在TSSE良好的截留性能中发挥着重要作用。本研究表明，TSSE可能为工业提供一种具有高去离子潜力的技术解决方案，以符合美国环境保护局对燃煤发电设施排放流的规定。
