نوع مقاله : مقاله پژوهشی
نویسندگان
گروه محیط زیست، دانشکده محیط زیست، دانشگاه تهران، تهران ، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Introduction: Aseptic containers are multilayer packaging materials widely used in the food industry. These packaging materials play an important role in preserving the quality and taste of food products and, by providing high resistance to external contaminants, help maintain the freshness and shelf life of food items. However, the complex and composite structure of these packages, consisting of multiple layers of polyethylene and aluminum, has turned their recycling process into a serious challenge. The aim of this study was to explore the possibility of using solvents to separate and recycle polyethylene-aluminum (Al-PE) composites from aseptic containers and to improve their recycling process.
Materials and Methods: In this study, Al-PE composites were obtained from a recycling company after undergoing the hydro-pulping process. To evaluate the possibility of polyethylene dissolution and its separation from aluminum, ten different solvents were tested, including xylene, toluene, ethanol, formic acid, water, isopropyl alcohol, acetic acid, methanol, gasoline, and ethyl acetate. The experiments were conducted in two stages: the first stage, preliminary screening at 60°C, and the second stage, additional tests at 90°C.
Results and Discussion: In the preliminary screening, it was found that xylene and toluene, due to their aromatic structure and moderate polarity, were the most effective solvents for dissolving low-density polyethylene (LDPE). These solvents, due to their high ability to dissolve and swell LDPE polymer chains, achieved the highest dissolution percentages. In the second stage, increasing the temperature to 90°C significantly improved the dissolution rate and amount of LDPE. Additionally, adding water to these solvents in small volumetric ratios effectively enhanced polyethylene dissolution. Optimization of the conditions showed that a volume mixture of xylene, toluene, and water in a ratio of 10:37:53 could achieve up to 95% LDPE dissolution. Furthermore, to explore the use of cheaper and more accessible solvents, gasoline was evaluated due to its high concentration of BTEX compounds. The results showed that using gasoline could achieve up to 85% LDPE dissolution.
Conclusion: This study demonstrated that using solvents, especially aromatic compounds such as xylene and toluene, can be an effective approach for separating and recycling Al-PE composites from aseptic containers. Additionally, gasoline was introduced as an economical and accessible alternative that could play a significant role in improving the economic viability of the recycling process.
کلیدواژهها [English]
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