DSI-NRF SARChI Clean Coal Technology Research Group, School of Chemical and Metallurgical Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Private Bag X3, Wits 2050, Johannesburg, South Africa.
Fachbereich Material-Und Geowissenschaften, Technische Universität Darmstadt, Otto-Berndt- Straße 3, 64287, Darmstadt, Germany.
Environ Sci Pollut Res Int. 2023 Sep;30(41):93786-93799. doi: 10.1007/s11356-023-28661-z. Epub 2023 Jul 29.
A simple mixing-pressing followed by thermal curing and pyrolysis process was used to upcycle coal waste into high-value composites. Three coal wastes of different physicochemical properties were investigated. The hypothetical mechanisms of bonding between the coal particles and the preceramic polymer are presented. The textural properties of the coals indicated that the lowest volatile coal waste (PCD) had a dense structure. This limited the diffusion and reaction of the preceramic polymer with the coal waste during pyrolysis, thereby leading to low-quality composites. The water contact angles of the composites up to 104° imply hydrophobic surfaces, hence, no external coating might be required. Analysis of the carbon phase confirmed that the amorphous carbon structure is prevalent in the composites compared to the coal wastes. The dc volume resistivity of the composites in the range of 22 to 82 Ω-cm infers that the composites are unlikely to suffer electrostatic discharge, which makes them useful in creating self-heating building parts. The leached concentrations of heavy metal elements from the composites based on the end-of-life scenario were below the Toxicity Characteristic Leaching Procedure regulatory limits. Additionally, the release potential or mobility of the metals from the composites was not influenced by the pH of the eluants used. On the basis of the reported results, these carbon/ceramic composites show tremendous prospects as building materials due to these properties.
采用简单的混合压制，随后进行热固化和热解工艺，将煤矸石升级为高价值复合材料。研究了三种具有不同物理化学性质的煤矸石。提出了煤颗粒与先驱体聚合物之间键合的假设机制。煤的结构性质表明，挥发性最低的煤矸石（PCD）具有致密的结构。这限制了先驱体聚合物在热解过程中与煤矸石的扩散和反应，从而导致复合材料质量较低。复合材料的水接触角高达 104°，表明其表面具有疏水性，因此可能不需要外部涂层。对碳相的分析证实，与煤矸石相比，复合材料中普遍存在无定形碳结构。复合材料的直流体积电阻率在 22 至 82 Ω-cm 的范围内推断出，复合材料不太可能遭受静电放电，这使得它们在制造自加热建筑部件方面很有用。基于使用寿命结束情景，从复合材料中浸出的重金属元素浓度低于毒性特征浸出程序法规限制。此外，金属从复合材料中的释放潜力或迁移性不受所用浸出剂 pH 值的影响。根据报告的结果，由于这些特性，这些碳/陶瓷复合材料作为建筑材料具有巨大的前景。
