Recycling of Polymers in the Presence of Nanocatalysts: A Green Approach towards Sustainable Environment

Authors: Beena Sethi

Abstract:

This work involves the degradation of plastic waste in the presence of three different nanocatalysts. A thin film of LLDPE was formed with all three nanocatalysts separately in the solvent. Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetric (DSC) analysis of polymers suggest that the presence of these catalysts lowers the degradation temperature and the change mechanism of degradation. Gas chromatographic analysis was carried out for two films. In gas chromatography (GC) analysis, it was found that degradation of pure polymer produces only 32% C3/C4 hydrocarbons and 67.6% C5/C9 hydrocarbons. In the presence of these catalysts, more than 80% of polymer by weight was converted into either liquid or gaseous hydrocarbons. Change in the mechanism of degradation of polymer was observed therefore more C3/C4 hydrocarbons along with valuable feedstock are produced. Adjustment of dose of nanocatalyst, use of nano-admixtures and recycling of catalyst can make this catalytic feedstock recycling method a good tool to get sustainable environment. The obtained products can be utilized as fuel or can be transformed into other useful products. In accordance with the principles of sustainable development, chemical recycling i.e. tertiary recycling of polymers along with the reuse (zero order recycling) of plastics can be the most appropriate and promising method in this direction. The tertiary recycling is attracting much attention from the viewpoint of the energy resource.

Keywords: Degradation, differential scanning calorimetry, feedstock recycling, gas chromatography, thermogravimetric analysis. DSC.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1124055

References:

[1] Albertsson AC, Andersson SO, Karlsson S. The mechanism of biodegradation of polyethylene. Polym Degrad Stab 1987; 18:73–87.
[2] Jayasekara R, Harding I, Bowater I, Lornergan G. Biodegradability of selected range of polymers and polymer blends and standard methods for assessment of biodegradation. J Polym Environ 2005; 13:231–51.
[3] Andrady, A.L. Microplastics in the marine environment. Mar. Pollut. Bull. 2011, 62, 1596–1605.
[4] Raquez, J.-M.; Bourgeois, A.; Jacobs, H.; Degée, P.; Alexandre, M.; Dubois, P. Oxidative degradations of oxodegradable LDPE enhanced with thermoplastic pea starch: thermo-mechanical properties, morphology, and UV-ageing studies. J. Appl. Polym. Sci. 2011, 122, 489–496.
[5] Yamada-Onodera, K.; Mukumoto, H.; Katsuyaya, Y.; Saiganji, A.; Tani, Y. Degradation of polyethylene by a fungus, Penicillium simplicissimum YK. Polym. Degrad. Stabil. 2001, 72, 323–327.
[6] Müller, R.-J.; Kleeberg, I.; Deckwer, W.-D. Biodegradation of polyesters containing aromatic constituents. J. Biotechnol. 2001, 86, 87–95.
[7] Francis, R. Sethi, B.” Catalytic Feedstock recycling of Polymers: A Green Approach towards sustainable Environment” World congress of Engineering and Technology, Beijing, China, 26-28, October, 2012.(pp 249).ISSN 2162-531X.
[8] K. C Kirkwood, S. A Leng, and David, “Stem cracking of unconventional hydrocarbon feedstocks for production of petrochemicals”. Proceedings of 45th International Petroleum Conference June 13, 2011, Bratislava, Slovak Republic.
[9] J. Walenzievski, “Continuous flow cracking of waste plastics”. Fuel Process. Technol. vol. 86, pp. 1265- 1272, 2005.
[10] W. Kaminsky, and F. Hartman, “Simulation and experiments of polyethene pyrolysis in a Fuildized Bed Process”. Proceedings of III International Symphosium of Feedstock Recycling of Plastics and other Innovative Recycling Techniques. Karlsruhe, Germany, Sept 25-29, (2000). pp 201.
[11] M. Predel, and W. Kaminsky, “Feedstock recycling of polymers by pyrolysis in a fluidised bed”. Polymer. Degradation Stabil. vol.70, pp. 373-378, (2000).
[12] P. T. Williams, and E. A. Williams, “Pyrolysis of post consumed waste plastics for the recovery of btx-aromatics using a fluidized bed reactor”. J. Anal. Appl. Pyrolysis, vol. 51, pp. 107-112, 1999.
[13] W. Kaminsky, and H. Sinn, “Recycling and Recovery of Plastics, Hanser, New York” . Proceedings of III International Symphosium of Feedstock Recycling of Plastics and other Innovative Recycling Techniques. Karlsruhe, Germany, Sept 25-29, pp 435-442. 2005.
[14] Francis, R.; Sethi, B. Catalytic Feedstock Recycling of Polymers a Green Approach Towards Sustainable Environment. Scientific Research Advances in Materials Physics and Chemistry, 2012, 2, 263-266.
[15] Achilias, D.S. Chemical Recycling of Polymers: The Case of Poly (methyl methacrylate) Proceedings of the 2006 IASME/WSEAS International Conference on Energy & Environmental Systems, Chalkida, Greece, May 8-10, 2006 (pp271-276)
[16] Dimitris S. Achilias et al. Material Recycling – Trends and PerspectivesRecent Advances in the: Chemical Recycling of Polymers (PP, PS, LDPE, HDPE, PVC, PC, Nylon, PMMA)
[17] J. Aguado, and D. P. Serrano, “Feedstock Recycling of Plastic Wastes”. Cambridge: Royal Society of Chemistry. 1999.
[18] D. P. Serrano, J. Aguado, G. Vicente, N. Sanchez, and L. Estebon, “Enhanced Production of ά-Olefins by thermal degradation of HDPE in De Calin Solvent”. 2000.
[19] S. Suga, Y. Wakayama, and T. Funazukuri, “Hydrothermal dechlorination of Poly (vinylchloride) in the absence and the presence of hydrogen peroxide”. Polym, Degrad, Stab. vol. 67, pp. 285 -298, 2000.
[20] R. Maraghi, Disposal, recycling and reuse. In Mosta Fa N.; Dekker, M. Editors, Plastic Waste Management. New York, USA; pp 223-226. 1993.
[21] I. Mita, Effect of structure on degradation and stability of polymers. In Aspect of Degradation and Stabilization of Polymers (ed. Jellinek, H. H. G.) 1978, Ch. 6, 247–294 (Elsevier, Amsterdam).
[22] J. Leonard, Heats and entropies of polymerization, ceiling temperatures, equilibrium monomer concentrations, and polymerizability of heterocyclic compounds. In Polymer Handbook Fourth Edition (eds, Brandrup, J., Immergut, E. H., & Grulke, E. A.) Ch. II, 363–414 (Wiley Interscience, New York, 1999).
[23] S. Kumar, A. K. Panda, and R. K. Singh. “A review on tertiary recycling of high- density Poly ethylene to fuel”. Conservation and Recycling, vol. 55, pp. 893-910, 2011.
[24] Uemichi, Y. Makino, and T. Kanazuka, “Degradation of polypropylene to aromatic hydrocarbons over Pt- and Fe-containing activated carbon catalysts”. J. Anal. Appl. Pyrol. vol.16, pp. 229-232, 1989.