## 1 Introduction  
Among antibiotics, amoxicillin is one of the most frequently administered globally [1, 2]. Its action in the human and animal body helps combat bacterial infections. Studies suggest that more than half of the ingested amoxicillin is eliminated by the human body and released into the environment [3, 4]. Additionally, its molecule has a property known as recalcitrance. This property causes amoxicillin to persist in conventional effluent treatments and become increasingly prevalent in environments worldwide. Previous studies [5] have shown that amoxicillin has been found in food, wastewater treatment plants, and sewage. The presence of antibiotics in the environment not only leads to environmental pollution problems but also contributes to the proliferation of antibiotic resistance. Furthermore, hepatotoxicity, nephropathy, and cancer are some examples of health problems that drug residues can cause in human health [6, 7].  
Several studies have been dedicated to the development of techniques for the degradation of amoxicillin [5, 8, 9, 10] and other pharmaceutical compounds [11, 12, 13]. Among these techniques are sonocatalysis [8], ozonation [14], electrochemistry [15], Fenton [16], and photocatalysis [9]. Heterogeneous photocatalysis is a technique capable of generating hydroxyl radicals when photocatalysts are exposed to visible or ultraviolet light. These radicals have high oxidation power and low selectivity. These characteristics enable these radicals to react with a wide variety of molecules [17; 18], including the amoxicillin molecule.  
In recent years, nanoscale photocatalysts have been developed through green routes. The nanoscale enables the enhancement of certain characteristics of these catalysts, such as increased surface area [19]. Green synthesis allows the generation of nanomaterials that do not harm, pollute, or degrade the environment. In the green route, microorganisms, residues, and plants can be used to aid in the formation of green nanoparticles [20; 21]. Additionally, it is worth noting that the green route utilizing plants is more feasible due to the speed of the process and its lower risks [21].  
Metals that can be used in this synthesis can be extracted from salts, such as sulfates and chlorides. Iron, zinc, copper, manganese, and magnesium are some examples of metals that can be synthesized through the green route in the production of nanostructures. Iron is a widely used metal in this synthesis as it yields excellent results in the degradation of recalcitrant compounds as a photocatalyst. A previous study [22] states that iron-based nanostructures possess characteristics such as ferroelectricity and magnetism.  
In this study, we used the peel of hybrid pumpkin to synthesize iron nanostructures through the green route and employed them as photocatalysts under UV light. The selection of hybrid pumpkin peel was based on its rich composition of bioactive compounds, which act as natural reducing and stabilizing agents, facilitating the formation of nanostructures without the need for hazardous chemicals. Additionally, pumpkin peels are by-products generated in the food processing industry [23]. Therefore, their use in nanocatalyst production represents an alternative for the valorization of this residue. This green nanophotocatalyst was used to investigate the photodegradation of the recalcitrant antibiotic amoxicillin, aiming to provide a potential eco-friendly and efficient alternative for water treatment applications.