Zhang et al. synthesized CoFe2O4-graphene hybrid materials (CFGHs) with different GO/CoFe2O4 weight ratios by employing Dafeng et al.'s combustion technique. The as-synthesised CFGHs outperformed pure CoFe2O4 in their ability to photocatalytically degrade Methylene Blue (MB) when exposed to visible light. The hydrothermal method was used to manufacture multi-walled carbon nanotube (MWCNT) hybrids and spinel nickel ferrite with different concentrations of MWCNT. The study aimed to explore the photocatalytic activity of NiFe2O4/MWCNT hybrids in decolourizing Congo Red (CR) in an aqueous solution using simulated solar light irradiation. This innovative fusion has the potential to effectively address a wide range of dyestuff effluent on a large scale. Using GO and various metal ions as starting materials, Bai et al. developed a one-pot solvothermal synthesis process to create hybrids of reduced graphene oxide (rGO) supported ferrite (MFe2O4, M = Mn, Zn, Co, and Ni). These hybrids have proven to be highly effective adsorbents for removing dye pollution. Researchers have discovered that a concentration of 0.6 g/L of combinations can eliminate 100% of MB and over 92% of Rhodamine B (RhB) in 2 minutes, with a 5 mg/L concentration. The hybrids also show improved photocatalytic activity in MB and RhB degradation. This research could make a new, straightforward separation platform for decontaminating wastewater available. Sun et al. devised a straightforward hydrothermal synthesis technique to create a magnetically separable photocatalyst composed of P25/CoFe2O4/graphene. The quantity of P25 in the catalyst was varied. The result shows that the P25/CoFe2O4/graphene photocatalyst surpasses other photocatalysts, such as CoFe2O4/graphene, P25/CoFe2O4, and P25/graphene, in terms of both the adsorption process and photocatalytic degradation. Xiong et al. have developed a simple two-step hydrothermal cadmium sulfide-ferrite nanocomposite (NC) (CdS-MFe2O4, where M can be either Zn or Co) with different ferrite concentrations. The addition has improved photocatalytic stability and efficiency under visible light irradiation, and it may be employed as a magnetically recoverable photocatalyst. When exposed to visible light, the degradation of 4-chlorophenol (4-CP) and RhB in a water-based solution was assessed to determine the material's photocatalytic performance. Fu et al. devised a simple technique for creating a CuFe2O4-graphene hetero-architecture through hydrothermal fabrication. This structure has a variety of uses, including magnetic cycling, increased photocatalytic activity when exposed to light, and remarkable electrochemical behaviours that make it suitable for use as the anode in lithiumion batteries. The photocatalytic activity data show that the formerly inert CuFe2O4 drastically changes and becomes a highly active catalyst for the breakdown of MB when coupled with graphene. Ji, Haiyan, et al. used a straightforward chemisorption approach to create new magnetic graphitic carbon nitride g-C3N4/NiFe2O4 photocatalysts. After five runs with hydrogen peroxide (H2O2) and visible light illumination, the 7.5% g-C3N4/NiFe2O4 composite exhibits high and stable photocatalytic activity as prepared. Zhang et al. used a one-step chemical coprecipitation method to successfully create magnetic composites of ZnFe2O4 and BiVO4. By doping ZnFe2O4 with a narrow band gap, BiVO4's photocatalytic activity was enhanced. This resulted in a larger production of photo-produced electrons and a higher absorption of visible light when compared to pure BiVO4. Yao et al used a simple reflux approach to synthesize magnetic ZnFe2O4-C3N4 hybrids. They employed graphitic C3N4 sheets and ZnFe2O4 nanoparticles (NPs) (about 19.1 nm in size) in methanol at 90°C. The catalytic activity of heterogeneous ZnFe2O4-C3N4 catalysts was assessed utilising orange II's photo-Fenton discolouration procedure. This approach involved the use of H2O2 as an oxidant as well as visible light irradiation (> 420 nm). The results of five distinct studies consistently demonstrated that the heterogeneous ZnFe2O4-C3N4 hybrid operated successfully and without loss of activity. This demonstrates a realistic use for the photo-oxidative degradation of organic contaminants. Wu, et al. proposed a simple method for incorporating magnetic ZnFe2O4 NPs into a rGO network. This was accomplished by utilising highly reactive ZnOx(OH)y and FeOx colloids as precursors. The precursors were synthesised by laser ablation of metallic zinc (Zn) and iron (Fe) targets in distilled water. The resulting nanocrystals significantly improved the photodegradation efficacy of the MB dye. Furthermore, the remarkable magnetic characteristics of the ZnFe2O4 NPs enable facile catalyst recovery by magnetic separation from the solution. This study expands the potential use of ZnFe2O4 NPs as photocatalysts, which may be triggered by visible light to destroy organic contaminants. Furthermore, it devised a unique method for synthesising ZnFe2O4-rGO (NCs). Khadgi et al. used a straightforward one-pot hydrothermal method to commercialize ZnFe2O4, a photocatalyst that is responsive to visible light, by combining it with graphene oxide (GO) and silver NPs. Consequently, they synthesized NC referred to as ZnFe2O4-Ag/rGO. This NC was evaluated for its photocatalytic efficiency using visible light to degrade 17-ethinylestradiol (EE2), a non-dye chemical compound regarded as an emerging pollutant with endocrine-disrupting effects. Chen et al. researched the degradation of 2,4dichlorophenol (2,4-DCP) using a new photocatalyst composed of a magnetically separable NC of rGO, ZnFe2O4, and silver phosphate (Ag3PO4). The photocatalyst was created using the solvothermal and in situ precipitation methods. According to the study, rGO/ZnFe2O4/Ag3PO4 NC demonstrated superior photocatalytic activity and stability compared to pure Ag3PO4. Kulkarni et al. reported that magnetically separable core-shell ZnFe2O4@ZnO NPs could break down aqueous Methyl orange (MO) under visible light by photodegradation. ZnFe2O4@ZnO NPs are efficient solar photocatalysts because they can be easily separated using a magnet, have a surface area of 41 m 2 /g, and can absorb visible light. ZnFe2O4@ZnO NPs have superior UV photocatalytic efficiency compared to ZnO. This is a result of the massive generation of electron-hole pairs. It has been documented for the first time that ZnFe2O4@ZnO NPs can be utilized for visible light photodegradation of MO. The ZnFe2O4@ZnO NPs have high photocatalytic efficiency and can be reused multiple times, indicating their applicability for solar photocatalytic applications. N-doped TiO2/ZnFe2O4 catalysts were effectively synthesised using one-pot vapor-thermal coupling of nitrogenmodified TiO2 and ZnFe2O4. Yao et al. examined the hybrids' UV-vis photocatalytic capabilities. Furthermore, the effects of catalyst stability, dye type, and amount on the photodegradation of organic dyes were examined. This study presents an easily recyclable photocatalyst for water filtration, as well as a simple method for creating N-doped TiO2/ZnFe2O4 hybrids. Wu et al. produced Ag/ZnO/ZnFe2O4 ternary composites with hollow and porous nanostructures using a straightforward calcination procedure. Zn3Fe(CN)6.xH2O, an Ag-loaded Prussian blue analogue, served as the precursor for this synthesis (Ag-ZnPBA). Compared to its binary cousin, ZnO/ZnFe2O4, the ternary Ag/ZnO/ZnFe2O4 demonstrated noticeably greater photocatalytic activity in the degradation of organic dye. This result emphasises how important Ag is to the photocatalytic process. The study offers a quick and efficient method for creating multi-component, homogenous NCs with interesting topologies and a range of uses. Ren et al. used a hydrothermal approach and a microwave-assisted synthesis process to create unique NiFe2O4/Bi2O3 heterostructures. These structures have visible light photocatalytic activity and were used for the degradation of antibiotics. The photocatalytic activity of the NiFe2O4/Bi2O3 heterostructures was significantly higher than that of a single semiconductor in removing tetracycline from water. Fu et al. plan to manufacture a magnetically separable NiFe2O4-graphene photocatalyst with varying graphene contents using a straightforward method. It is intriguing to note that when NiFe2O4 NPs and graphene sheets are combined, the inert NiFe2O4 undergoes a dramatic transformation into a highly active catalyst capable of breaking down MB when exposed to visible light. 3. Spinel ferrites based on synthesis methods 3.1 Sol-gel Method: Ivanets, Andrei, et al. used Fenton-like catalyst MgFe2O4 and metal-loaded MFe2O4 NPs [(M)-Mn 2+ , Co 2+ , Ni 2+ , and Cu 2+ ] to degrade MB in water in a recent work. The primary emphasis of the investigation was on the catalytic breakdown of MB and the impact of metal ions absorbed into MgFe2O4. The outcomes show that MgFe2O4 may be a useful adsorbent and catalyst for eliminating organic pollutants and dangerous metal ions from multicomponent water solutions. Magnetic CuFe2O4 spinel NPs were synthesised by Feng et al. These NPs were used as catalysts to activate H2O2 for sulfanilamide heterogeneous degradation via external energy-free Fenton-like processes. Desai and his team have utilised the auto-combustion method to produce MnFe2O4 NPs. They used a combination of MnFe2O4 and mM solutions of H2O2 for the degradation of MB dye by photocatalysis under sunshine. In this study, Trier et al. used the sol-gel method to synthesise Cu1-xCoxFe2O4 spinel ferrite NPs for 6 hours at 600 °C with cobalt content (x = 0, 0.3, and 0.5). Sol-gel technology was employed to produce MnFe2O4 spinel ferrite NPs as catalysts for the oxidative disintegration of MO. These NPs feature delicate magnetic response properties and a large specific surface area. The tests showed that they have a strong catalytic activity for the breakdown of MO. Due to their unique properties, MnFe2O4 spinel ferrite NPs may be used in water treatment. Jasrotia, Rohit, and colleagues employed sol-gel auto-combustion to synthesise Ni-Cu-Zn nanosized spinel ferrites doped with Ag + , Mn 2+ and Cr 3+ ions. The chemical formula of the synthesised specimens is Zn0.3Ag0Ni0.4Cu0. 3.4xCr0.3xMn0.3xFe2-xO4 (ZANCuCrMFO) (where x = 0.0, 0.05, 0.10, 0.15). The study aimed to investigate synthesised specimens' microstructural, optical, magnetic, and electrical properties. Muhammad et al. utilised the sol-gel method to prepare copper ferrites with indium (In) substitution, having the nominal composition CuInxFe2-xO4 (where x = 0.00 to 0.32). The synthesised ferrites exhibited low coercivity and dielectric parameters, indicating the potential benefits of using indium-substituted copper ferrites in high-frequency and switching applications. Khirade, Pankaj P. et al. investigated how different synthesis methods affected the qualities of the structure, microstructure, magnetic, electrical, and dielectric of Mg1-xZnxFe2O4 nanocrystals prepared using the ceramic and environmentally friendly solgel method (where x = 0.00 to 0.32). Researchers Samoila and Petrisor and their team used sol-gel auto combustion with citric acid as the fuel agent to create nanosized spinel ferrites MFe2O4 (where M can be Ni, Co, or Zn). They discovered that using NiFe2O4 as an adsorbent, a single-objective optimisation produced an impressive 98.995% colour removal efficiency. Furthermore, the adsorption capacity and removal efficiency improved due to the multi-objective optimisation.