Adsorption of H₂S onto porous materials is as an attractive technology for fine biogas cleaning. Three activated carbon samples were studied as adsorbents for biogas desulfurization at low concentration (100 ppm), in order to better understand the underlying mechanisms and provide a basis for the development of new materials. One of the carbons is impregnated with NaOH, another with Fe₂O₃ and the third one is the parent material. Molecular simulation was performed to distinguish the retention mechanism. Textural characterization revealed high surface areas and the existence of ultramicropores with sizes below 4 Å in all samples. The possibility of discriminating the retention regimes emphasized the great influence of the chemisorption in these systems increasing up to 50 times the capacity of retention of H₂S for the sodium-impregnated sample (from 0.3 to 15.64 mg g^–1). Surprisingly, both physisorption and chemisorption could be unequivocally detected for the nonimpregnated sample by evaluating breakthrough curves in different temperatures (up to 423 K). The evaluation of regeneration by heat indicated that the adsorbents can recover about 50% and 20% of their initial capacity for nonimpregnated and impregnated samples, respectively.

中文翻译：

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对低浓度H ₂ S保留碳的机理的见解

H ₂ S在多孔材料上的吸附是一种用于精细沼气清洁的有吸引力的技术。为了更好地理解其潜在机理，并为开发新材料提供了基础，研究了三种活性炭样品作为低浓度（100 ppm）沼气脱硫的吸附剂。其中一种碳用NaOH浸渍，另一种碳用Fe ₂ O ₃浸渍第三个是母材料。进行分子模拟以区分保留机制。纹理表征表明，所有样品中都具有较高的表面积和尺寸小于4Å的超微孔。区分保留方式的可能性强调了化学吸附在这些系统中的巨大影响，使H ₂ S对钠浸渍样品的保留容量增加到50倍（从0.3到15.64 mg g ^–1）。）。令人惊讶的是，通过评估不同温度（最高423 K）下的穿透曲线，可以明确地检测未浸渍样品的物理吸附和化学吸附。对热再生的评估表明，对于未浸渍和浸渍的样品，吸附剂可以分别恢复其初始容量的约50％和20％。