Leveraging the Potential of In Situ Green-Synthesized Zero-Valent Iron Nanoparticles (nZVI) for Advanced Oxidation of Clinical Dyes in Water  
[PERSON]  
Departamento de Quimica Organica e Inorginica, Facultad de Ciencias, Universidad de Extremadura,  
Avenida de Elvas s/n, 06006 Badajoz, Spain; [EMAIL_ADDRESS] (M.F.A.-F.); [EMAIL_ADDRESS] (C.R.-R.); [EMAIL_ADDRESS] (A.G.-T.); [EMAIL_ADDRESS] (M.C.-P.); [EMAIL_ADDRESS] (C.F.-G.)  
[PERSON]  
Departamento de Quimica Organica e Inorginica, Facultad de Ciencias, Universidad de Extremadura,  
Avenida de Elvas s/n, 06006 Badajoz, Spain; [EMAIL_ADDRESS] (M.F.A.-F.); [EMAIL_ADDRESS] (C.R.-R.); [EMAIL_ADDRESS] (A.G.-T.); [EMAIL_ADDRESS] (M.C.-P.); [EMAIL_ADDRESS] (C.F.-G.)  
[PERSON]  
Departamento de Quimica Organica e Inorginica, Facultad de Ciencias, Universidad de Extremadura,  
Avenida de Elvas s/n, 06006 Badajoz, Spain; [EMAIL_ADDRESS] (M.F.A.-F.); [PERSON]DRESS] (C.R.-R.); [EMAIL_ADDRESS] (A.G.-T.); [EMAIL_ADDRESS] (M.C.-P.); [EMAIL_ADDRESS] (C.F.-G.)  
[PERSON]  
Departamento de Quimica Organica e Inorginica, Facultad de Ciencias, Universidad de Extremadura,
environmental monitoring and assessment. They are used as tracers in studies related to water flow, hydrology, and pollution monitoring [4]. Dyes can help track the movement and dispersion of contaminants, identify pollution sources, and evaluate the effectiveness of environmental remediation efforts [5]. Finally, dyes have significant applications in scientific research, particularly in areas such as molecular biology, genetics, and cell biology [6]. Different dyes are used as fluorescent probes, indicators, or stains to visualize and study biological processes, cellular structures, and genetic material [6; 7]. Dyes also play crucial roles in medical diagnostics and research, as they are used as contrast agents in medical imaging techniques such as X-rays, CT scans, and angiography to enhance visibility and highlight specific structures or functions in the body [8]. Chrysodine G (4-Phenylazo-m-phenylenediamine monohydochloride, C\({}_{12}\)H\({}_{12}\)N\({}_{4}\cdot\)HCI, CAS Number 532-82-1) has been used in various medical applications, including wound healing, as it has shown antibacterial properties against certain types of bacteria commonly found in wound infections. In addition, chrysodine has demonstrated antifungal activity against some species of fungi, particularly those causing superficial fungal infections such as dermatophytes [9]. Methylene blue (Methylthioninium chloride, 3,7-bis(Dimethylamino)phenothiazzin-5-ium Chloride, C\({}_{16}\)H\({}_{18}\)C\({}_{13}\)S, CAS Number 61-73-4) has found use in different medical fields, such as diagnostic staining [10] and the treatment of urinary tract infections [11] or methemoglobinitia [12], a disease characterized by the presence of an abnormal form of hemoglobin in the blood. In addition, methylene blue has shown potential neuroprotective properties [13] and has been investigated as a therapeutic agent for neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease [14; 15], as well as an adjunctive treatment for depression [16]. Despite their beneficial uses, chrysodine and methylene blue can pose environmental risks including toxicity for aquatic or terrestrial organisms [17; 18; 19; 20] and water pollution [21; 22; 23]. Furthermore, these adverse effects may be reinforced due to the potential of these molecules to bioaccumulate in organisms and their environmental persistence, which increase the potential for long-term exposure to organisms and ecosystems, amplifying the environmental risks. To mitigate these hazards, it is necessary to use a range of methods that can remove or reduce the concentrations of these chemicals, preferably before discharging the effluents. The remediation of chrysodine and methylene blue in water can be achieved through various treatment methods.