A new concept of edge shrinkage, case deduced from the treatment of Pet-Al residues of post-consumed food cartons with an alkaline solution

• Main Authors: Aymen Souilhi, Rym Abidi
• Format: Article
• Language: English
• Published: Elsevier 2021-10-01
• Series: Cleaner Engineering and Technology
• Subjects: Edge shrinkage; Flat shape; Aymen edge model; Aluminium hydroxyde; Alkaline solution
• Online Access: http://www.sciencedirect.com/science/article/pii/S2666790821002044

This study aims to develop a mathematical model that can explain the regeneration process mechanism of the aluminum which is in the packaging of food bricks (the Pet-Al residue Rsd(Pet-Al) is a laminated foil residue made from polyethylene and aluminum foil) as a raw material in alkaline solution and evaluate that model based on the experimental data. In fact, the literature shows that a symmetrical diffusion of the reagent occurs through the two sides of large bare surfaces, this is true when both surfaces of the solid are naked. In our case, the Pet-Al residue suggests another mode of attack seeing that both of aluminium surfaces are covered with polyethylene. For that, a new Edge Shrinking model called “Aymen Edge Model” was invented. The process mechanism that occurs involves the reactant diffusion step and the chemical reactions step; those steps run simultaneously. The concentration of free hydroxyls OH− in the solution compared to the reference solution, [OH-]solution - [OH-]reference = f(t), gives an idea of the different stages observed during of the consumed hydroxyls evolution. The SEM micrographs resulting, after a basic treatment, with concentration from 1M to 10M at a temperature ranging from 20 to 80 °C, proves that the attack is done by the edges and also confirm the obtaining salts.