| Abstrakt: |
Plastic pollution has become one of the global environmental threats to humans and the whole world. Plastics do not exist without the chemicals that emitted at every stage of their life cycle - from oil extraction to production, and disposal, especially when plastic waste is not disposed properly, but rather stored in the open air on unprotected soil near water sources. Chemical recycling of plastic waste, which is based on catalytic cracking, prevents the emission of toxic chemicals into the environment; produces liquid oils and additives for various fuels; and avoids significant energy costs using mechanical and thermal processing methods. Catalytic cracking of plastics in the presence of natural and synthetic zeolite catalysts allows to produce a wide range of aromatic hydrocarbons. The modified samples of CaY-based catalysts were used in the catalytic cracking of polystyrene, as a type of thermoplastic polymer. Depending on the selected type of zeolite catalyst (ZSM-5, Ni-ZSM-5, USY, NiHY), the practical yield the components of the liquid fraction was determined, as follows: styrene, styrene dimer, styrene trimer, ethylbenzene, methylstyrene, cumene, and others. The yield of styrene using ZSM-5 is 42 %, at Ni-ZSM-5 - 5.97 %, at USY - 1.26 %, at NiHY - 47.37 %. The yield of the liquid fraction at ZSM-5 is 67.2 %, at Ni-ZSM-5 - 38.5 %, at USY - 15 %, at NiHY - 70.3 %. According research results, it was found that the most selective and effective catalyst (among the above) for polystyrene cracking was a nickel-modified alumosilicate (NiHY). The yield of the liquid fraction using the NiHY catalyst is 70.3 %, and the yield of styrene is 47.37 %. In conclusion, the further development of catalysts is necessary to improve the selectivity and efficiency of low-temperature catalytic cracking reactions to obtain secondary raw materials for the synthesis of polystyrene. [ABSTRACT FROM AUTHOR] |
