## 3 Magnetic Ferrite Nanoparticles for Wastewater Treatment
### Organic Compounds  
Organic pollutants include a wide range of chemicals, such as pesticides, pharmaceuticals, and dyes [91; 92]. Unlike other pollutants, many organic compounds can undergo biological degradation, but their persistence in water systems depends on their chemical structure and environmental conditions [93; 94]. Most dyes used in the textile industry are synthetic, including azo dyes, anthraquinone dyes, and triarymethane dyes [95; 96]. These dyes are chemically stable and resistant to biodegradation, leading to their accumulation in water [97]. azo dyes, which account for around 60-70% of all dyes used, are of particular concern due to their breakdown products, such as aromatic amines, which are highly toxic and potentially carcinogenic [98]. When released into water, azo dyes can undergo a reduction in anaerobic conditions, producing harmful byproducts that pose significant risks to aquatic organisms and humans [99].  
Pesticides and pharmaceuticals are another critical group of organic pollutants [100]. While pesticides are designed to be toxic to specific organisms, they can also affect non-target species in aquatic environments [101; 102]. For instance, organophosphates and carbamates, widely used insecticides, can disrupt the nervous systems of fish, amphibians, and aquatic invertebrates [103; 104]. Persistent pesticides, such as organochlorines, can accumulate in the fatty tissues of marine organisms, leading to biomagnification in the food chain and causing reproductive and developmental issues in wildlife and humans [105; 106]. Antibiotics, hormones, and analgesics are emerging contaminants that conventional water treatment plants are not designed to remove effectively, resulting in persistence in groundwater [107; 108; 109]. Even low concentrations of pharmaceuticals in water have been shown to disrupt endocrine systems in aquatic organisms, leading to altered reproduction, growth, and behavior [110]. For example, exposure to synthetic hormones from contraceptives can cause feminization of male fish, impairing their reproductive success [111; 112]. The combination of pesticides and pharmaceuticals in wastewater often results in additive or synergistic effects, exacerbating their cytotoxic and genotoxic impacts [113; 114]. Presented as a complex mixture, pesticides and pharmaceuticals can interact to enhance oxidative stress, disrupt endocrine systems, and amplify genetic damage [115]. Studies have reported that the presence of multiple contaminants can intensify DNA damage markers and micronucle in exposed organisms [113]. Chronic exposure to these mixtures has been linked to long-term effects such as reproductive impairments, growth inhibition, and increased susceptibility to diseases in aquatic species [116; 117].  
Organic compounds such as pesticides, pharmaceuticals, and dyes can be removed from wastewater by adsorption or decomposition [118; 119]. In the case of adsorption, ferrite nanoparticles are used for heavy metal removal, and a high surface area is needed for an efficient process [120]. However, ferrites can also be used in composites, which absorb UV or visible light and generate reactive oxygen species. The reactive oxygen species can decompose the organic compounds, in this way cleaning the wastewater [121]. The approach of applying ferrite nanoparticles in the photocatalytic decomposition of organic pollutants is a novel research area; however, there are several reports on this topic.