## 3 Results and Discussion
### Environmental Feasibility
These characteristics exclude it from the category of environmentally hazardous substances, making it an ideal choice for applications in industrial wastewater remediation [90]. On the other hand, magnetite (Fe\({}_{3}\)O\({}_{4}\)) is a non-toxic, low-cost substance with a mass-production capacity [91], widely used in coupling with other photocatalysts to improve recoverability by magnetic separation [92]. According to [PERSON] et al. [93], the toxicity of nanocatalysts is highly dependent on the exposure dose in the environment, and the system's magnetic recovery can significantly mitigate the risks [94]. In addition, it has been shown that coated Fe\({}_{3}\)O\({}_{4}\) nanoparticles do not present ecotoxicity in plants [95]. Overall, bismuth-based nanoparticles have essential attributes that have been evaluated in the cosmetic and pharmaceutical industry over time, standing out for their minimal or no zero toxicity, stability, abundance in the Earth's crust, and affordability [96; 97]. Figure 14: Chile’s photovoltaic power potential (kWh/kWp). Notes: This figure shows Chile’s photovoltaic power potential, which refers to how much energy (kWh) is produced per kilowatt peak of a system. The figure was retrieved from [[https://globalsolaratlas.info](https://globalsolaratlas.info)]([https://globalsolaratlas.info](https://globalsolaratlas.info)). Solar resource data were obtained from the Global Solar Atlas. This map was published by the World Bank Group, funded by ESMAP, and prepared by Solargis (accessed 25 August 2024) [40]. Concerning the disposal of the spent catalyst, the EPA [98] classifies waste as hazardous or non-hazardous under the Resource Conservation and Recovery Act, USA., RCRA 94-580, 1976 [99]. Waste is considered hazardous if it has any of the following characteristics: ignitability, corrosivity, reactivity, or toxicity. The BiOI/magnetic photocatalyst, under the conditions studied, does not show properties that classify it as ignitable, corrosive, reactive, or toxic. In the European Union, waste classification is governed by the Waste Framework Directive (2008/98/EC, 2008) [100], which establishes the criteria for determining whether waste is hazardous. The regulations evaluate aspects such as acute toxicity, ecotoxicity, and persistence in the environment. BiOI/magnetic does not contain substances listed as hazardous in the European classification of hazardous waste (LWP 2014/955/EU) [101] and also does not qualify as a hazardous substance in the Classification, Labeling, and Packaging of Substances and Mixtures-CLP Regulation [102]. In the context of where Pisco Endemico is located, and according to the Chilean Government's Supreme Decree SD. 148, 2004 [103], waste or a mixture thereof is considered hazardous if it presents a risk to public health and/or adverse environmental effects, either directly or as a result of its current or planned management. In the case of the BiOI/magnetic photocatalyst used, none of its constituent substances are classified as hazardous according to Chilean legislation RE. 777, 2021 [104], which makes it possible to rule out its dangerousness both in its application as an active substance and in its management as waste. It is important to note that although BiOI/magnetic can be considered non-hazardous waste under the regulations mentioned above, its handling must follow the best waste management practices to minimize any potential environmental impact. Hence, the proposed advanced technology offers an environmentally feasible system, both in waste management and in implementing the photocatalytic process using solar radiation, representing a potential alternative in environmental sustainability for managing water resources in arid zones. It also considers that better management of water and sanitation services contributes to addressing the serious problem of water availability, as well as to reducing health risks and promoting environmental protection [105].