The pyrolysis and catalytic reforming process of waste plastics are the best pathways to handle vast amounts of waste plastics as they can convert these waste polymers into sustainable products. This study aims to incorporate a natural-clay-mineral (NCM) with LaFeO₃ nanoparticles, with the LaFeO₃/NCM catalyst in the pyrolysis of polypropylene (PP) being used as an example of plastic waste. The decomposition of PP with and without catalyst has been theoretically studied using thermogravimetry (TG) and differential scanning calorimetry (DSC) measurements under atmospheric pressure and nitrogen atmosphere. The TG/DSC results show that (i) the required temperature for pyrolysis of PP with or without catalyst in a practical system ranges from 460°C to 480°C; (ii) the amount of coke produced on the surface of the NCM or LaFeO₃ is about 2 wt.% compared with the initial plastic levels; (iii) with the catalyst, PP not only goes through the phase transitions of solid to liquid to gas but also decomposition and combination processes between components from the hydrocarbon chain scission of PP. Gas chromatography–mass spectrometry (GC–MS) results show significant differences in the fuel oil recovered from the pyrolysis and catalytic reforming process. In the presence of the catalyst, cracking components consist of 49.3% alkenes (branched-chain alkenes, cyclo-alkenes, and alkenes) and 34.4% alkanes, while without the catalyst, branched-chain alkenes were up to 90.2%. Repeated pyrolysis and GC–MS investigations demonstrated the reusability of the LaFeO₃/NCM catalyst, which is promising for its recycling and the efficient pyrolysis of PP.

中文翻译：

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LaFeO3 负载的天然粘土矿物催化剂用于聚丙烯塑料材料的高效热解

废塑料的热解和催化重整过程是处理大量废塑料的最佳途径，因为它们可以将这些废聚合物转化为可持续产品。本研究旨在将天然粘土矿物 (NCM) 与 LaFeO ₃纳米颗粒结合在一起，LaFeO ₃/NCM 催化剂在聚丙烯 (PP) 热解中被用作塑料废物的一个例子。使用热重法 (TG) 和差示扫描量热法 (DSC) 在大气压和氮气气氛下对 PP 的分解进行了理论研究。TG/DSC结果表明(i)在实际体系中有或没有催化剂的PP热解所需的温度范围为460°C至480°C；(ii) 在 NCM 或 LaFeO ₃表面产生的焦炭量与初始塑料水平相比约为 2 wt.%；(iii) 在催化剂的作用下，PP 不仅经历了固体到液体再到气体的相变，而且还经历了 PP 烃链断裂的组分之间的分解和组合过程。气相色谱-质谱 (GC-MS) 结果显示从热解和催化重整过程中回收的燃料油存在显着差异。在催化剂存在下，裂解组分由49.3%的烯烃（支链烯烃、环烯烃和烯烃）和34.4%的烷烃组成，而在没有催化剂的情况下，支链烯烃高达90.2%。反复的热解和 GC-MS 研究证明了 LaFeO ₃ /NCM 催化剂的可重复使用性，这对于它的回收和 PP 的有效热解是有希望的。