Aminolytic Depolymerisation of Polyethylene Terephthalate Wastes using Sn doped ZnO Nanoparticles

Abstract

Poly(ethylene terephthalate) (PET) is one of the most consumed polymers because of its excellent thermal and mechanical properties. By increasing in PET production and since the disposal of PET waste has growing to be a major global environmental issue each year. Chemical recycling is a most successful method to achieve circular economy in the PET utilizing industries. Current research work aims to complete depolymerization of waste PET from soft drink bottles by the aminolysis method to produce bis (2-hydroxy ethylene) terephthalamide (BHETA) in the presence of Sn doped ZnO. To evaluate catalytic activity, pure and Sn2+ doped ZnO nanoparticles prepared using different Sn2+ molar ratios at 0.5, 1.0 and 2.0 mol% and calcined at 500 0C for 1h. The synthesized catalysts characterised using FT-IR, XRD, and UV-vis spectroscopy. The surface morphology and percentage doping obtained from SEM and SEM-EDS, respectively. We have observed a reduction in optical band gap and crystallite size of ZnO due to tin doping. Aminolytic depolymerization of PET waste using ethanolamine promoted by Sn doped ZnO effectively under conventional thermal method. Increase in the yield of the BHETA observed with respect to increasing doping percentage of Sn and 1-2 mol% Sn doped ZnO nanoparticles afforded over 90% of BHETA. Structure and purity of BHETA, depolymerised product characterized by FT-IR, 1HNMR, 13C NMR, and MS.

Chemical Recycling of PET Polyester Textile Wastes Using Ag-Doped ZnO Nanoparticles: An Economical Solution for Circular Economy

“…The sol-gel method has been adopted successfully for the synthesis of Ag-doped ZnO nanoparticles. ZnO doped with 0.5, 1.0, 2.0, and 3.0 mol% was synthesised using the reported procedure (Vinitha et al 2022). Depending on the Ag loading, Agdoped ZnO was obtained as a light grey to grey powder.…”

“…Finally, the last image of green-coloured PES (VSAG3) (Fig. 14c), which gives a peak at 250.10 (M + H) attributed to the main product of BHETA, one more peak at m/z 283.15 clearly shows that the Na + form of BHETA due to electron spray ionization (Vinitha, 2022).…”

“…In our earlier investigation, the complete conversion of PET bottle wastes was achieved by aminolysis using Sn-doped ZnO at 155-160°C(Vinitha et al 2022). We hypothesized that Sn-doped ZnO nanoparticles may serve as a cost-effective and e cient catalyst for the aminolytic depolymerization of PET wastes with a high BHETA yield.…”