Refinery sour water primarily originates from the tops of towers in various units and coker condensate, and cannot be discharged directly to a wastewater treatment plant due to high levels of chemical oxygen demand (COD) and organic sulfur contents. Even after the recovery of HS from the sour water by the stripping process, the effluent still contains a high concentration of dissolved organic sulfur (DOS), which can have a huge bad influence. While chemical composition of dissolved organic matter (DOM) in refinery wastewater has been extensively studied, the investigation of recalcitrant DOS from sour waters remains unclear. In the present study, chemical composition of sour water DOMs (especially DOS) was investigated using fluorescence spectroscopy (excitation-emission matrix, EEM) and mass spectrometry, including gas chromatography-mass spectrometry (GC-MS) and high-resolution Orbitrap MS. The GC-MS and EEM results showed that volatile and low-aromaticity compounds were effectively removed during the stripping process, while compounds with high hydrophilicity and humification degree were found to be more recalcitrant. The Orbitrap MS results showed that weak-polar oxygenated sulfur compounds were easier to be removed than oxygenated compounds. However, the effluent still contained significant amounts of sulfur-containing compounds with multiple sulfur atoms, particularly in the form of highly unsaturated and aromatic compounds. The Orbitrap MS/MS results of CHOS-containing compounds from the effluent indicate that the sulfur atoms may exist as sulfonates, disulfide bonds, thioethers. Understanding the composition and structure of sour water DOS is crucial for the development of effective treatment processes that can target polysulfide compounds and minimize their impact on the environment.

中文翻译：

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汽提过程中炼油酸水中难溶有机硫转化的分子研究

炼厂酸水主要来源于各装置塔顶和焦化装置冷凝水，由于化学需氧量（COD）和有机硫含量较高，无法直接排放至污水处理厂。即使通过汽提工艺从酸性水中回收H2S，废水中仍然含有高浓度的溶解有机硫（DOS），这会产生巨大的不良影响。虽然炼油废水中溶解有机物 (DOM) 的化学成分已被广泛研究，但酸性水中顽固性 DOS 的研究仍不清楚。在本研究中，使用荧光光谱（激发发射矩阵，EEM）和质谱，包括气相色谱-质谱（GC-MS）和高分辨率 Orbitrap MS 研究了酸性水 DOM（尤其是 DOS）的化学成分。 GC-MS和EEM结果表明，挥发性和低芳香度化合物在汽提过程中被有效去除，而高亲水性和腐殖化度的化合物则更难以去除。 Orbitrap MS 结果表明，弱极性含氧硫化合物比含氧化合物更容易去除。然而，流出物仍然含有大量具有多个硫原子的含硫化合物，特别是高度不饱和的芳香族化合物。流出物中含 CHOS 化合物的 Orbitrap MS/MS 结果表明，硫原子可能以磺酸盐、二硫键、硫醚形式存在。了解酸性水 DOS 的成分和结构对于开发有效的处理工艺至关重要，该工艺可以针对多硫化物并最大限度地减少其对环境的影响。