Abstract: To address the challenge of low-temperature synergistic removal of carbonyl sulfide (COS) and elemental mercury (Hg⁰) from natural gas in the presence of H₂O, H₂S, and CS₂ impurities, a nitrogen-doped copper-loaded carbon aerogel (PPD-Cu/CA) with a venation-like fractal structure was prepared using sodium alginate as a template. The effects of these impurity gases on the synergistic removal of COS and Hg⁰ were systematically investigated at 40 ℃, and the underlying mechanisms and product evolution patterns were elucidated using SEM, CO₂-TPD, XPS, and Hg-TPD. The results show that an appropriate concentration of water vapor (1%) promotes COS hydrolysis and the oxidation of Hg⁰ to HgO by providing reactive oxygen species, achieving 100% synergistic removal of both COS and Hg⁰. In contrast, high concentrations of H₂S [(0-150)×10^-6] and CS₂ [(0-100)×10^-6]markedly inhibit COS conversion but have no appreciable effect on Hg⁰ removal. H₂S alters the surface chemistry of the catalyst by occupying basic sites and increasing the proportion of sulfate species, thereby poisoning Cu²⁺ active sites and consuming surface-adsorbed oxygen. This disrupts the Cu²⁺/Cu⁺ redox cycle required for COS hydrolysis and promotes the formation of CuS. Meanwhile, H₂S reacts with Hg⁰ to generate HgS, which accounts for 71.59% of the mercury-containing products. CS₂ competes with COS for the same basic sites, while the active sulfur species released during its decomposition shift the Hg⁰ transformation pathway from HgO formation to one dominated by HgS. The proportion of Cu²⁺ increases from 34.0% to 67.3%, whereas low-valent copper primarily forms Cu₂S, accompanied by an anomalous enrichment of surface-adsorbed oxygen. The venation-like fractal structure of the carbon aerogel promotes the dispersion of metal and nitrogen-doped active sites and enhances mass transfer, while the nitrogen-doped carbon support exhibits excellent stability and outstanding resistance to impurity interference.

Key words: carbonyl sulfide, elemental mercury, carbon aerogel, impurity gases, synergistic removal, nitrogen doping, copper loading

摘要： 针对天然气中羰基硫（COS）和单质汞（Hg⁰）低温协同脱除及存在H₂O、H₂S和CS₂杂质气体干扰的难题，以海藻酸钠为模板制备了具有分形叶脉结构的氮掺杂铜负载碳气凝胶（PPD-Cu/CA），在低温（40℃）条件下系统考察杂质气体对COS与Hg⁰协同脱除性能的影响，结合扫描电镜、CO₂程序升温脱附、X射线光电子能谱和汞程序升温脱附等表征手段揭示了可能的作用机制与产物演化规律。结果表明：适量水蒸气（1%）可以提供活性氧物种促进COS水解并氧化Hg⁰生成HgO，实现两者100%协同脱除；H₂S[(0~150)×10^-6]和CS₂[(0~100)×10^-6]高浓度下显著抑制COS转化，但对Hg⁰脱除无明显影响；H₂S通过占据碱性位点、促进硫酸盐类比例增加等方式改变催化剂表面化学环境，毒化Cu²⁺位点并消耗表面吸附氧，打断COS水解依赖的Cu²⁺/Cu⁺循环并生成CuS，同时可与Hg⁰生成HgS（占比为71.59%）；CS₂与COS消耗相同碱性位点，分解释放的活性硫也使Hg⁰转化路径由HgO生成逆转为HgS主导，Cu²⁺占比由34.0%升至67.3%，低价铜主要生成Cu₂S并伴随表面吸附氧反常富集；碳气凝胶材料的分形叶脉结构强化了金属和氮掺杂活性位点分散与传质，氮掺杂载体稳定性优异，抗杂质干扰性能突出。

关键词: 羰基硫, 单质汞, 碳气凝胶, 杂质气体, 协同脱除, 氮掺杂, 铜负载