Density-based solvent separation method for recycling mixed low-value plastic waste
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Huei Ruey Ong
,
Wan Mohd Eqhwan Iskandar
,
Mun Yung Au Yong
Abstract
The global plastic waste management faces significant challenges due to the increasing volume of mixed plastic waste streams. A systematic review of plastic waste separation technologies and characterization methods is essential to enhance recycling efficiency. This study examines separation technologies and quality validation methods for various plastic types through detailed analysis of operational parameters and industrial applications. The investigation focuses on both thermosetting plastics and thermoplastic materials including PP, ABS, PE and PS. The study implements multiple analytical characterization methods including Melt Flow Index (MFI), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA) and mechanical properties of the material. The findings suggest that systematic separation approaches based on material properties offer the most promising pathway toward sustainable plastic recycling solutions.
Acknowledgments
The authors would like to express their sincere gratitude to Geely University and DRB-HICOM University of Automotive Malaysia for their generous financial support and invaluable research assistance that made this study possible.
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Research ethics: Not applicable.
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Informed consent: Informed consent was obtained from all individuals included in this study, or their legal guardians or wards.
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Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Use of Large Language Models, AI and Machine Learning Tools: None declared.
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Conflict of interest: The authors state no conflict of interest.
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Research funding: None declared.
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Data availability: Not applicable.
References
1. Athulya, T.; Reshma, J. Plastic Pollution: A Global Crisis and the Overlooked Challenge of Low-Value Plastics. Ecol. Environ. Conserv. 2024, 30, 688–693; http://doi.org/10.53550/EEC.2024.v30i02.047.10.53550/EEC.2024.v30i02.047Suche in Google Scholar
2. Chen, H. L.; Nath, T. K.; Chong, S.; Foo, V.; Gibbins, C.; Lechner, A. M. The Plastic Waste Problem in Malaysia: Management, Recycling and Disposal of Local and Global Plastic Waste. SN Appl. Sci. 2021, 3, 1–15; https://doi.org/10.1007/s42452-021-04234-y.Suche in Google Scholar
3. Akkouri, N.; Baba, K.; Ait Elkassia, A. Valorization of Plastic Waste (PP-LDPE) from Moroccan Industry in Modification of Hybrid Bitumen: Application of the Mixture Design Methodology. Int. J. Pavement Res. Technol. 2023, 16 (3), 760–779; https://doi.org/10.1007/s42947-022-00162-1.Suche in Google Scholar
4. Ghani, U.; Zamin, B.; Tariq Bashir, M.; Ahmad, M.; Sabri, M. M. S.; Keawsawasvong, S. Comprehensive Study on the Performance of Waste HDPE and LDPE Modified Asphalt Binders for Construction of Asphalt Pavements Application. Polymers 2022, 14 (17), 3673; https://doi.org/10.3390/polym14173673.Suche in Google Scholar PubMed PubMed Central
5. Abdy, C.; Zhang, Y.; Wang, J.; Yang, Y.; Artamendi, I.; Allen, B. Pyrolysis of Polyolefin Plastic Waste and Potential Applications in Asphalt road Construction: A Technical Review. Resour., Conserv. Recycl. 2022, 180, 106213; https://doi.org/10.1016/j.resconrec.2022.106213.Suche in Google Scholar
6. Dan, E.; McCue, A. J.; Dionisi, D.; Fernández Martín, C. Household Mixed Plastic Waste Derived Adsorbents for CO2 Capture: A Feasibility Study. J. Environ. Manage. 2024, 355, 120466; https://doi.org/10.1016/j.jenvman.2024.120466.Suche in Google Scholar PubMed
7. Maris, J.; Bourdon, S.; Brossard, J. M.; Cauret, L.; Fontaine, L.; Montembault, V. Mechanical Recycling: Compatibilization of Mixed Thermoplastic Wastes. Polym. Degrad. Stab. 2018, 147, 245–266; https://doi.org/10.1016/j.polymdegradstab.2017.11.001.Suche in Google Scholar
8. Bernat, K. Post-Consumer Plastic Waste Management: From Collection and Sortation to Mechanical Recycling. Energies 2023, 16 (8), 3504; https://doi.org/10.3390/en16083504.Suche in Google Scholar
9. Lee, M. J.; Rahimifard, S. A Novel Separation Process for Recycling of Post-Consumer Products. CIRP Ann. 2012, 61 (1), 35–38; https://doi.org/10.1016/j.cirp.2012.03.026.Suche in Google Scholar
10. Zhang, Y.; Wang, Q.; Yalikun, N.; Wang, H.; Wang, C.; Jiang, H. A Comprehensive Review of Separation Technologies for Waste Plastics in Urban Mine. Resour., Conserv. Recycl. 2023, 197, 107087; https://doi.org/10.1016/j.resconrec.2023.107087.Suche in Google Scholar
11. Möllnitz, S.; Küppers, B.; Curtis, A.; Khodier, K.; Sarc, R. Influence of Pre-Screening on Down-Stream Processing for the Production of Plastic Enriched Fractions for Recycling from Mixed Commercial and Municipal Waste. Waste Manag. 2021, 119, 365–373; https://doi.org/10.1016/j.wasman.2020.10.007.Suche in Google Scholar PubMed
12. Selina, M.; Markus, B.; Daniel, S.; Renato, S. Wet-Mechanical Processing of a Plastic-Rich Two-Dimensional-Fraction from Mixed Wastes for Chemical Recycling. Waste Manag. Res. 2021, 39 (5), 731–743; https://doi.org/10.1177/0734242x21996435.Suche in Google Scholar PubMed
13. Rybarczyk, D.; Jędryczka, C.; Regulski, R.; Sędziak, D.; Netter, K.; Czarnecka-Komorowska, D. Assessment of the Electrostatic Separation Effectiveness of Plastic Waste Using a Vision System. Sensors 2020, 20 (24), 7201; https://doi.org/10.3390/s20247201.Suche in Google Scholar PubMed PubMed Central
14. Daioui, K.; Zeghloul, T.; Perbet, N.; Dascalescu, L. Tribo-Electrostatic Separation of Plastic Flakes Originating from Packaging Waste. J. Electrostat. 2025, 134, 104046; https://doi.org/10.1016/j.elstat.2025.104046.Suche in Google Scholar
15. Thijs, L.; Kuerten, J.; Zeegers, J.; Tajfirooz, S. Magnetic Density Separation of Particles in Honeycomb-Generated Wake Turbulence. Chem. Eng. Sci. 2023, 278, 118930; https://doi.org/10.1016/j.ces.2023.118930.Suche in Google Scholar
16. Cao, Y.; Sathish, C.; Guan, X.; Wang, S.; Palanisami, T.; Vinu, A. Advances in Magnetic Materials for Microplastic Separation and Degradation. J. Hazard. Mater. 2024, 461, 132537; https://doi.org/10.1016/j.jhazmat.2023.132537.Suche in Google Scholar PubMed
17. Dewi, R.; Sylvia, N.; Riza, M. Melt Flow Index (MFI) Analysis of Sago Based Thermoplastic Starch Blend with Polypropylene and Polyethylene. Mater. Today: Proc. 2023, 87, 396–400; https://doi.org/10.1016/j.matpr.2023.04.173.Suche in Google Scholar
18. Lynch, J. M.; Corniuk, R. N.; Brignac, K. C.; Jung, M. R.; Sellona, K.; Marchiani, J. Differential Scanning Calorimetry (DSC): An Important Tool for Polymer Identification and Characterization of Plastic Marine Debris. Environ. Pollut. 2024, 346, 123607; https://doi.org/10.1016/j.envpol.2024.123607.Suche in Google Scholar PubMed
19. Aghili, A.; Shabani, A. H. Application of the Orthogonal Collocation Method in Evaluating the Rate of Reactions Using Thermogravimetric Analysis Data. Thermochim. Acta 2024, 733, 179698; https://doi.org/10.1016/j.tca.2024.179698.Suche in Google Scholar
20. Khan, M. Q.; Alvi, M. A. H. Material Characterizations, in Engineering Materials: Fundamentals, Processing and Properties; Springer: Cham, Switzerland, 2024; pp 237–255.10.1007/978-3-031-72263-9_10Suche in Google Scholar
21. Ding, Y.; Guo, L.; Yang, J.; Li, Y.; Cao, Z.; Lu, G. Functionalisation of Multiwalled Carbon Nanotubes with Melamine Phosphate and their Influence on Morphology, Thermal Stability, Flame Retardancy and Mechanical Properties of ABS. Plast., Rubber Compos. 2021, 50 (2), 92–103; https://doi.org/10.1080/14658011.2020.1840200.Suche in Google Scholar
22. He, W.; Zhou, Y.; Chen, X.; Guo, J.; Zhou, D.; Chen, S. Novel Intumescent Flame Retardant Masterbatch Prepared Through Different Processes and its Application in EPDM/PP Thermoplastic Elastomer: Thermal Stability, Flame Retardancy, and Mechanical Properties. Polymers 2018, 11 (1), 50; https://doi.org/10.3390/polym11010050.Suche in Google Scholar PubMed PubMed Central
23. Li, J.; Pu, T.; Wang, Z.; Liu, T. Thermal Behavior and Pyrolysis Kinetics of Mushroom Residue with the Introduction of Waste Plastics. Polymers 2023, 15 (18), 3824; https://doi.org/10.3390/polym15183824.Suche in Google Scholar PubMed PubMed Central
24. Panupakorn, P.; Chaichana, E.; Praserthdam, P.; Jongsomjit, B. Polyethylene/Clay Nanocomposites Produced by in situ Polymerization with Zirconocene/MAO Catalyst. J. Nanomater. 2013, 2013 (1), 154874; https://doi.org/10.1155/2013/154874.Suche in Google Scholar
25. Villagómez-Salas, S. l.; Manikandan, P.; Acuña Guzmán, S. F.; Pol, V. G. Amorphous Carbon Chips Li-ion Battery Anodes Produced Through Polyethylene Waste Upcycling. Acs Omega 2018, 3 (12), 17520–17527; https://doi.org/10.1021/acsomega.8b02290.Suche in Google Scholar PubMed PubMed Central
26. Fu, N.; Zhang, S.; Ma, Y.; Yang, Z.; Liu, W. Diatomite/Cu/Al Layered Double Hydroxide Hybrid Composites for Polyethylene Degradation. RSC Adv. 2020, 10 (17), 9808–9813; https://doi.org/10.1039/c9ra10940d.Suche in Google Scholar PubMed PubMed Central
27. Wojtyła, S.; Klama, P.; Baran, T. Is 3D Printing Safe? Analysis of the Thermal Treatment of Thermoplastics: ABS, PLA, PET, and Nylon. J. Occup. Environ. Hyg. 2017, 14 (6), D80–D85; https://doi.org/10.1080/15459624.2017.1285489.Suche in Google Scholar PubMed
28. Zhi, Y.-R.; Yu, B.; Yuen, A. C. Y.; Liang, J.; Wang, L. Q.; Yang, W. Surface Manipulation of Thermal-Exfoliated Hexagonal Boron Nitride with Polyaniline for Improving Thermal Stability and Fire Safety Performance of Polymeric Materials. ACS omega 2018, 3 (11), 14942–14952; https://doi.org/10.1021/acsomega.8b02316.Suche in Google Scholar PubMed PubMed Central
29. Li, M.; Sheng, L.; Zhang, H.; Yang, Y.; Xu, R.; Bai, Y. Effect of the Heat Treatment Temperature on Mechanical and Electrochemical Properties of Polyimide Separator for Lithium Ion Batteries. J. Mater. Sci. 2020, 55, 16158–16170; https://doi.org/10.1007/s10853-020-05197-y.Suche in Google Scholar
30. Ray, S.; Cooney, R. P. Thermal Degradation of Polymer and Polymer Composites. In Handbook of Environmental Degradation of Materials; Elsevier: Norwich, NY, 2018; pp 185–206.10.1016/B978-0-323-52472-8.00009-5Suche in Google Scholar
31. Aumnate, C.; Pongwisuthiruchte, A.; Pattananuwat, P.; Potiyaraj, P. Fabrication of ABS/Graphene Oxide Composite Filament for Fused Filament Fabrication (FFF) 3D Printing. Adv. Mater. Sci. Eng. 2018, 2018 (1), 2830437; https://doi.org/10.1155/2018/2830437.Suche in Google Scholar
32. Manola, M. S. Investigation of Melt Flow Index of Dual Metal Reinforced ABS Polymer for FDM Filament Fabrication. Mater. Today: Proc. 2023, https://doi.org/10.1016/j.matpr.2023.02.188.Suche in Google Scholar
33. Aumnate, C. Recycling Of PP/LDPE Blend: Miscibility, Thermal Properties, Rheological Behavior and Crystal Structure. In Annual Technical Conference-ANTEC, Conference Proceedings; Society of Plastics Engineers: Brookfield, CT, USA, 2016; pp 81–87.Suche in Google Scholar
34. da Cunha Santos, A.; Cáceres, C.; Calixto, L.; Zborowski, L.; Canevarolo, S. In-line Optical Techniques to Characterize the Polymer Extrusion. Polym. Eng. Sci. 2014, 54 (2), 386–395; https://doi.org/10.1002/pen.23569.Suche in Google Scholar
35. Abdel-Hakim, A.; Al-harbi, A. M.; Sadek, A. Characterization of Melt Flow Index of Commercial Polystyrene Using Data from Interlaboratory Comparison. MAPAN 2021, 36 (1), 47–58; https://doi.org/10.1007/s12647-020-00394-1.Suche in Google Scholar
36. Khanam, P. N.; AlMaadeed, M. A. A. Processing and Characterization of Polyethylene-Based Composites. Adv. Manuf.: Poly. Compos. Sci. 2015, 1 (2), 63–79; https://doi.org/10.1179/2055035915y.0000000002.Suche in Google Scholar
37. Rosales, C.; Aranburu, N.; Otaegi, I.; Pettarin, V.; Bernal, C.; Müller, A. J. Improving the mechanical performance of LDPE/PP blends through microfibrillation. ACS Appl. Polym. Mater. 2022, 4 (5), 3369–3379; https://doi.org/10.1021/acsapm.1c01932.Suche in Google Scholar
38. Biron, M. Thermoplastic Specific Properties; Material Selection for Thermoplastic Parts: Kidlington, Oxford, UK, 2016; pp 39–75.10.1016/B978-0-7020-6284-1.00002-7Suche in Google Scholar
39. Shrivastava, A. Introduction to Plastics Engineering; William Andrew: Kidlington, Oxford, UK, 2018.10.1016/B978-0-323-39500-7.00001-0Suche in Google Scholar
40. Scoppio, A.; Cavallo, D.; Müller, A. J.; Tranchida, D. Temperature Modulated DSC for Composition Analysis of Recycled Polyolefin Blends. Polym. Test. 2022, 113, 107656; https://doi.org/10.1016/j.polymertesting.2022.107656.Suche in Google Scholar
41. Linares Veliz, A. B.; Jiménez, J. C.; López, P.; De Gáscue, B. R. Biodegradability Study by FTIR and DSC of Polymers Films Based on Polypropylene and Cassava Starch. Orbital 2019, 11 (2), 71–82; https://doi.org/10.17807/orbital.v11i2.1360.Suche in Google Scholar
42. Jhang, J.-C.; Chen, Y. S.; Lou, C. W.; Lin, J. H. Investigation on the Rebound Rate for Polymeric Composites and Nonwoven Needle Punched Fabrics at Various Depths. J. Ind. Text. 2021, 50 (9), 1516–1527; https://doi.org/10.1177/1528083719899654.Suche in Google Scholar
43. Souza, B. R.; Di Benedetto, R. M.; Hirayama, D.; Raponi, OdA.; Barbosa, L. C. M.; Ancelotti Junior, A. C. Manufacturing and Characterization of Jute/PP Thermoplastic Commingled Composite. Mater. Res. 2017, 20 (Suppl 2), 458–465; https://doi.org/10.1590/1980-5373-mr-2017-0104.Suche in Google Scholar
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