Arcibar-Orozco Javier A, Wallace Rajiv, Mitchell Joshua K, Bandosz Teresa J
Department of Chemistry, The City College of New York , New York, New York 10031, United States.
Langmuir. 2015 Mar 10;31(9):2730-42. doi: 10.1021/la504563z. Epub 2015 Feb 26.
Composites of magnetite and two-line ferrihydrite with graphite oxide (GO) were synthesized and tested as hydrogen sulfide adsorbents. Exhausted and initial composites were characterized by the adsorption of nitrogen, X-ray diffraction, potentiometric titration, thermal analysis, and FTIR. The addition of GO increased the surface area of the composites due to the formation of new micropores. The extent of the increase depended on the nature of the iron (hydr)oxide and the content of GO. The addition of GO did not considerably change the crystal structure but increased the number of acidic functional groups. While for the magnetite composites an increase in the H2S adsorption capacity after GO addition was found, the opposite effect was recorded for the ferrihydrite composites. That increase in the adsorption capacity was linked to the affinity of the composites to adsorb water in mesopores of specific sizes in which the reaction with basic surface groups takes place. Elemental sulfur and ferric and ferrous sulfates were detected on the surface of the exhausted samples. A redox reactive adsorption mechanism is proposed to govern the retention of hydrogen sulfide on the surface of the composites. The incorporation of GO enhances the chemical retention of H2S due to the incorporation of OH reactive groups and an increase in surface heterogeneity.
合成了磁铁矿与二水合铁酸氢盐和氧化石墨烯（GO）的复合材料，并将其作为硫化氢吸附剂进行测试。通过氮气吸附、X射线衍射、电位滴定、热分析和傅里叶变换红外光谱对耗尽的和初始的复合材料进行了表征。由于形成了新的微孔，GO的添加增加了复合材料的表面积。增加的程度取决于铁（氢）氧化物的性质和GO的含量。GO的添加没有显著改变晶体结构，但增加了酸性官能团的数量。虽然对于磁铁矿复合材料，添加GO后硫化氢吸附容量增加，但对于铁酸氢盐复合材料则记录到相反的效果。吸附容量的增加与复合材料在特定尺寸的中孔中吸附水的亲和力有关，在这些中孔中会发生与碱性表面基团的反应。在耗尽样品的表面检测到了元素硫以及硫酸铁和硫酸亚铁。提出了一种氧化还原反应吸附机制来控制硫化氢在复合材料表面的保留。由于引入了OH反应基团和表面不均匀性的增加，GO的掺入增强了H2S的化学保留。
