In this study, a three-dimensional (3D) porous sponge capable of oil–water separation was fabricated using recycled expanded polystyrene (EPS) through 3D electrospinning, by adding phosphoric acid to the electrospinning solution. The fabrication process was a rapid and efficient single-step process to produce the 3D sponge. In addition, the additive’s concentration was also optimized for oil absorption. The fabricated EPS sponge was highly effective in oil–water separation due to its excellent hydrophobic and oleophilic properties. This demonstrates its potential as a sustainable and efficient absorbent to address ongoing oil pollution issues. Moreover, the performance of the recycled EPS sponge was found to be comparable to that of sponges made from virgin polystyrene, suggesting the feasibility of using recycled materials for the production of high-value products. This research presents an efficient method for fabricating 3D sponges from recycled materials, contributing to environmental protection and resource recycling.

Superhydrophobic surfaces, i.e., surfaces with a water contact angle (WCA) ≥ 150°, have gained much attention as they are multifunctional surfaces with features such as self-cleaning, which can be useful in various applications such as those requiring waterproof and/or protective films. In this study, we prepared a solution from recycled polyethylene terephthalate (PET) and fabricated a superhydrophobic surface using electrospinning and electrospraying processes. We observed that the fabricated geometry varies depending on the solution conditions, and based on this, we fabricated a hierarchical structure. From the results, the optimized structure exhibited a very high WCA (>156.6°). Additionally, our investigation into the self-cleaning functionality and solar panel efficiency of the fabricated surface revealed promising prospects for the production of superhydrophobic surfaces utilizing recycled PET, with potential applications as protective films for solar panels. Consequently, this research contributes significantly to the advancement of environmentally friendly processes and the progress of recycling technology.