Indirect Photochemical Formation of Carbonyl Sulfide and Carbon Disulfide in Natural Waters: Role of Organic Sulfur Precursors, Water Quality Constituents, and Temperature
Indirect Photochemical Formation of Carbonyl Sulfide and Carbon Disulfide in Natural Waters: Role of Organic Sulfur Precursors, Water Quality Constituents, and Temperature
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DOI：
10.1021/acs.est.8b01618
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发表时间：
2018-08-21
影响因子：
11.4
通讯作者：
Shah, Amisha D.
中科院分区：
文献类型：
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作者：
Gharehveran, Mahsa Modiri;Shah, Amisha D.
羰基硫（COS）和二硫化碳（CS2）是挥发性硫化合物，是硫酸盐气溶胶的关键前体，使气候变冷。COS和CS2来源于天然沃茨中有机硫前体的间接光解，但目前这背后的化学过程仍不清楚。本研究评估了不同的有机硫前体，水质成分，这可以形成重要的活性中间体（RIs），以及温度如何影响COS和CS2的形成。九个自然沃茨的盐度范围内掺入半胱氨酸，胱氨酸，二甲硫醚（DMS），或蛋氨酸，并暴露于模拟阳光在不同的时间和水质条件。结果表明，COS和CS2的形成增加了11倍和4倍，分别在12小时的阳光照射后，而昼夜循环表现出不同的效果。COS和CS2的形成也受到DOC浓度、有机硫前体物类型、O-2浓度和温度的强烈影响，而盐度差异和CO添加没有起到显着的作用。总体而言，确定了形成COS和CS2的重要因素，这些因素可能最终影响其大气浓度。
Carbonyl sulfide (COS) and carbon disulfide (CS2) are volatile sulfur compounds that are critical precursors to sulfate aerosols, which enable climate cooling. COS and CS2 stem from the indirect photolysis of organic sulfur precursors in natural waters, but currently the chemistry behind how this occurs remains unclear. This study evaluated how different organic sulfur precursors, water quality constituents, which can form important reactive intermediates (RIs), and temperature affected COS and CS2 formation. Nine natural waters ranging in salinity were spiked with cysteine, cystine, dimethylsulfide (DMS), or methionine and exposed to simulated sunlight over varying times and water quality conditions. Results indicated that COS and CS2 formation increased up to 11x and 4x, respectively, after 12 h of sunlight, while diurnal cycling exhibited varied effects. COS and CS2 formation was also strongly affected by the DOC concentration, organic sulfur precursor type, O-2 concentration, and temperature, while salinity differences and CO addition did not play a significant role. Overall, important factors in forming COS and CS2 were identified, which may ultimately impact their atmospheric concentrations.