## 1 Introduction  
In recent years, there has been a substantial rise in global plastic waste, leading to serious environmental and public health challenges [1]. In 2018, annual plastic production reached 359 million tons, and it is expected to double by 2050. In Mexico, the per capita plastic waste generation is 59 kg annually, with less than 10% being recycled [2]. In 2023, the Mexican Secretariat of Environment and Natural Resources (SEMARNAT) identified polypropylene (PP), low-density polyethylene (LDPE), and polystyrene (PS) as the primary polymers contributing to environmental pollution, with PS having the lowest recycling potential based on a cost-benefit ratio [2]. In response, the Mexican government, following international initiatives, proposed a policy for sustainable development and a circular economy to enhance waste management practices. A key initiative within this framework is the redesign and reuse of plastic products. Specifically, recycling and transforming polystyrene--available in several forms, such as expanded polystyrene (EPS), general-purpose polystyrene (GPPS), and high-impact polystyrene (HIPS)--is crucial for reducing PS waste in the environment and promoting sustainable materials for various applications. Recently, single-use polystyrene (PS) waste has been identified as a valuable material for the circular economy [3; 4; 5]. For example, nanofiber membranes from expanded polystyrene (EPS) waste with different poly(vinylpyrrolidone) (PVP) concentrations were elaborated by electrospinning for their use in water filtration [6]. PVP introduction reduced EPS's high hydrophobicity on the membrane surface, changing their water contact angle from 140.46\({}^{\circ}\) to 84.70\({}^{\circ}\) and increasing pure water flux from 526.86 L m\({}^{-2}\)h\({}^{-1}\) to 1901.35 L m\({}^{-2}\)h\({}^{-1}\). The introduction of carbon nanotubes is also a strategy to obtain a more hydrophilic membrane surface with lower fouling properties [7]. [PERSON] et al. developed an ultra-fast method to produce recycled EPS membranes using DL-limonene as a natural solvent, with adequate characteristics for its applications in air filtration [8]. Moreover, the production of ion exchange resins from polystyrene waste, sulfonated with sulfuric acid, has been reported for heavy metals (Cu\({}^{2+}\). Zn\({}^{2+}\), and Cd\({}^{2+}\)) removal in wastewater [9; 10; 11], as well as for the adsorption of fluoroquinolone, a second-generation synthetic antibiotic [12]. Membranes from sulfonated PSE blended with 1% of polybutylene succinate (PBS) exhibited a higher methylene blue uptake and good regeneration efficiency, compared with membranes containing a higher PBS amount, following a pseudo-second order kinetic model in the adsorption process [13]. The utilization of HIPS waste has been less extensively studied, despite its notable advantages over brittle and rigid EPS and GPPS [14; 15]. HIPS offers superior impact resistance, flexibility, and stability, making it a promising candidate for various applications. [PERSON] et al. investigated the potential use of recycled HIPS as a partial replacement for fine aggregates in lightweight concrete and evaluated the impact on key properties, such as compressive strength, flexural strength, and bond strength. The authors concluded that recycled HIPS at 10% concentration is an optimal level for achieving lightweight concrete with desirable mechanical properties, offering a sustainable solution for recycling plastic waste in construction materials [16]. Moreover, cation exchange resins for the removal of heavy metal ions (Zn\({}^{2+}\), Pb\({}^{2+}\)) were prepared from sulfonated polystyrene waste (WPS) containing HIPS and EPS. These cation exchange resins were capable of reducing Zn\({}^{2+}\) metal concentration from 80 mg/L to 38.3 mg/L and Pb\({}^{2+}\) from 100 mg/L to 33 mg/L by an absorption process [17]. Air filter membranes were also fabricated from a HIPS waste solution in a D-limonene:DMF mixture using needleless electrospinningning.