A LaFeO₃ supported natural‐clay‐mineral catalyst for efficient pyrolysis of polypropylene plastic material

Abstract

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.

Influence of Natural Zeolites on the Thermal Decomposition of Multi-layered Plastic Waste

“…Many studies have been conducted on pyrolysis of plastic materials through TGA analysis [21,[34][35][36][37][38][39][40]. These studies are based mostly on the pyrolysis of a single type of plastic or co-pyrolysis of two or more different types of plastics, like LDPE, PP, PS, PET, and PP.…”

Catalytic Pyrolysis of Plastic Waste and Molecular Symmetry Effects: A Review

“…An interesting study was carried out by Nguyen et al [85] in which the pyrolysis of PP waste plastics in the presence of natural-clay-mineral NCM, with LaFeO 3 nanoparticles, was studied. The degradation of PP was investigated using thermogravimetry (TG) and differential scanning calorimetry (DSC).…”

Thermocatalytic Conversion of Plastics into Liquid Fuels over Clays

“…In summarizing, the highest liquid yields were obtained for LDPE on Fuller’s earth catalyst (91 wt%) [ 18 ]; PP on natural clay mineral from Indonesia impregnated with LaFeO 3 nanoparticles (88.8 wt% on the 5th cycle) [ 60 ]. It should be stressed that in the latter case, the yield growth was provided by the specific efficient promoter—lanthanum ferrite.…”