Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China.
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China.
J Hazard Mater. 2021 Jul 5;413:125289. doi: 10.1016/j.jhazmat.2021.125289. Epub 2021 Feb 2.
Red mud (RM) as bauxite residue from aluminum plant was investigated as cost-effective catalyst for pyrolysis and ex-situ catalytic conversion of plastic wastes into H-rich syngas and magnetic carbon nanocomposites. The results showed that the introduction of RM catalyst elevated gas yield from 23.8 to 60.3 wt% as a rise of catalytic temperature (700-850 °C), due to its high iron activity for scission of polymer chains. Furthermore, the endothermic nature of cracking reactions of hydrocarbons led to the maximum H production of 28.8 mmol g and 63 vol% at 850 °C. The carbon/RM nanocomposites were comprehensively evaluated by multiple characterizations. High-resolution TEM indicated considerable carbon nanotubes(CNTs) depositing on the RM surface that modified iron sites dispersion and diminished nanoparticle size of iron at higher temperature of ≥800 °C. XRD and XPS results confirmed that higher temperature provided carbon components surrounding iron species to form metallic iron. The carbon/RMs were initially applied to chromium(VI) removal in sewage. RM-800 delivered high-profile adsorption capacity of 193.8 mg g, mainly attributed to the synergistic effect of chemical reduction by sufficient Fe exposure and CNTs growth promoting electrostatic attraction and electron transfer capacity. Furthermore, the correlation mechanism between catalytic temperature and the evolution of products and was discussed.
红泥（RM）是铝厂的铝土矿废渣，被研究为一种具有成本效益的催化剂，用于热解和原位催化转化塑料废物为富 H 的合成气和磁性碳纳米复合材料。结果表明，由于 RM 催化剂中铁的高活性，可促进聚合物链的断裂，因此，在 700-850°C 的催化温度范围内，引入 RM 催化剂可将气体产率从 23.8%提高到 60.3%wt。此外，碳氢化合物的裂解反应是吸热反应，在 850°C 时，H 的最大产率为 28.8mmol g 和 63vol%。通过多种表征对碳/RM 纳米复合材料进行了综合评价。高分辨率 TEM 表明，大量碳纳米管（CNTs）沉积在 RM 表面上，这改变了铁位的分散性，并在更高的温度（≥800°C）下减小了铁纳米颗粒的尺寸。XRD 和 XPS 结果证实，较高的温度为铁物种周围的碳成分提供了形成金属铁的条件。最初将碳/RM 应用于污水中的六价铬（Cr(VI)）去除。RM-800 表现出 193.8mg g 的高吸附容量，主要归因于充分暴露的 Fe 进行的化学还原和 CNTs 生长促进的静电吸引和电子传递能力的协同效应。此外，还讨论了催化温度与产物演变之间的相关机制。
