Metal decorated montmorillonite as a catalyst for the degradation of polystyrene

Benefiting a renewable source of precious hydrocarbons and getting rid of a huge environmental pollutant like polystyrene is the cry of the day. Waste polystyrene (PS) represents a source of valuable chemical products like styrene and other aromatics. Therefore, metals decorated montmorillonite (Mt) catalysts were prepared using Mg, Zn, Al, Cu and Fe and were evaluated for the tertiary recycling of waste polystyrene. The metal decorated catalysts characterized by N-2 adsorption/desorption, XRD & SEM techniques. 20% Fe/Mt and 5% Al/Mt were found with high activity for the production of liquid products and good selectivity for the production of low molecular weight aromatic products like styrene, toluene and ethylbenzene, etc. The yield of toluene, ethylbenzene, styrene and a-methylstyrene was 8.49 wt.%, 5.13 wt.%, 49.28 wt.% and 2.80 wt.%, respectively using 5% Al/Mt catalyst and it was 10.15 wt.%, 6.42 wt.%, 50.93 wt.% and 2.31 wt.%, respectively using 20% Fe/Mt catalyst. The results showed that among the metal decorated Mt catalysts used, 5% Al/Mt and 20% Fe/Mg were found to be the most effective catalyst for selective conversion into aromatics. The products contained styrene monomer as a major along with toluene, ethylbenzene and a-methylstyrene value added products. Thus, it was possible to demonstrate the feasibility of catalytic degradation as an alternative technology for the chemical recycling of waste PS. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.