## 1 Introduction  
Metal-organic frameworks (MOFs) have emerged as a class of porous materials with exceptional potential for a wide range of applications, including gas storage, separation, and catalysis [1]. Their unique structural characteristics, namely the fact that they comprise inorganic metal ions or clusters connected by organic linkers, offer a high degree of tunability and flexibility [2]. Among MOFs, MIL-100(Fe) has garnered significant attention due to its high surface area, large pore volume, and exceptional thermal and chemical stability [3, 4]. Furthermore, its low toxicity, relatively low cost, and hydrothermal stability makes MIL-100(Fe) an ideal material for industrial applications [5]. In fact, iron-based metal-organic frameworks (e.g., MIL-100(Fe)) are particularly important due to their low toxicity, good stability, earth abundance, cost-effectiveness, and biocompatibility, making them ideal for several applications [6]. Their synthesis is generally more sustainable, aligning with green chemistry principles [7]. These features position Fe-MOFs as attractive candidates for various industrial applications, including drug delivery, sensing, catalysis, energy storage, and environmental remediation [5, 8]. MIL-100(Fe) was synthesized for the first time hydrothermally by the authors of [9], using HF as a mineralizing agent. The proposed synthesis conditions were rather harsh and employed metallic iron, hydrofluoric acid, nitric acid, trimesic acid, and water, and a reaction was carried out at 150 \({}^{\circ}\)C for six days. [PERSON] et al. [10] improved the hydrothermal synthesis procedure, obtaining fluoride-free MIL-100(Fe) in large quantities. The chemical formula of MIL-100(Fe) was found to be as follows by elemental analysis [11]:  
\[\left[\mathrm{Fe}_{3}|\mathrm{O}|\big{(}\mathrm{H}_{2}\mathrm{O})_{2}\mathrm{ F}_{0.8}(\mathrm{OH})_{0.2}\{\mathrm{C}_{6}\mathrm{H}_{3}(\mathrm{CO}_{2})_{3} \}_{2}.\mathrm{nH}_{2}(\mathrm{n}\approx 14.8)\right] \tag{1}\]  
Among the various methods employed for the synthesis of MIL-100(Fe), including dry gel conversion synthesis, mechano-chemical synthesis, microwave-assisted synthesis, and low-temperature water-based synthesis, hydrothermal synthesis emerges as the most prominent and promising approach [12]. This technique, although not always characterized by green chemical constituents, stands out for its simplicity, scalability, and ability to produce MIL-100(Fe) with high crystallinity, phase purity, and controlled particle size [10; 12; 13]. Hydrothermal synthesis is able to eliminate the need for harsh solvents and toxic reagents, making it a more environmentally friendly and efficient approach for MOF synthesis. It utilizes mild temperature and pressure conditions to facilitate controlled dissolution, crystallization, and growth of MOFs, resulting in high-quality, well-defined structures. Additionally, hydrothermal synthesis offers tunability over various parameters, such as temperature, pH, and reaction time, allowing for precise control over MOF properties and morphology [14; 15]. However, despite the previously mentioned beneficial features, purification of MOFs in hydrothermal synthesis is crucial yet challenging due to structural complexities and impurities. Most MOFs are synthesized through slow cooling in hydrothermal or solvothermal methods. To maintain purity and minimize byproducts, selecting precise starting material molar ratios is vital [16]. The presence of unreacted constituents and the subsequent use of environmentally unfriendly solvents, such as DMF and NH\({}_{4}\)F, limit the ecological balance and industrial scalability of this synthesis technique [17]. In light of this concern, extensive explorative research was carried out to develop additional green synthesis methods, with the primary goal of reducing safety hazards and cutting down on the environmental footprint stemming from manufacturing processes.