One-step hydrothermal synthesis and microwave electromagnetic properties of RGO/NiFe2O4 composite

The reduced graphene oxide (RGO)/NiFe₂O₄ composite was synthesized by a facile one-pot hydrothermal route, which avoided the usage of chemical reducing agent. The reduction of graphene oxide (GO) and the crystallization of NiFe₂O₄ crystals happened in a one-step hydrothermal process. The morphology, microstructure and magnetic properties of the composite were detected by means of XRD, XPS, TEM, EDX, TG-DSC and VSM. The maximum R_L of the RGO/NiFe₂O₄ composite is −39.7 dB at 9.2 GHz with the thickness of 3.0 mm, and the absorption bandwidth with the R_L below −10 dB is up to 5.0 GHz (from 12.7 to 17.7 GHz) with a thickness of 1.9 mm. The introduction of RGO signally enhanced microwave absorption performance of the NiFe₂O₄ NPs. It is believed that such composite will be applied widely in microwave absorbing area.     

Facile synthesis of Co0.5Zn0.5Fe2O4 nanoparticles decorated reduced graphene oxide hybrid nanocomposites with enhanced electromagnetic wave absorption properties

Herein, reduced graphene oxide/cobalt-zinc ferrite (RGO/Co_0.5Zn_0.5Fe₂O₄) hybrid nanocomposites were fabricated by a facile hydrothermal strategy. Results revealed that the contents of RGO could affect the micromorphology, electromagnetic parameters and electromagnetic wave absorption properties. As the contents of RGO increased in the as-synthesized hybrid nanocomposites, the dispersibility of the particles was improved. Meanwhile, numerously ferromagnetic Co_0.5Zn_0.5Fe₂O₄ particles were evenly anchored on the wrinkled surfaces of flaky RGO. Besides, the obtained hybrid nanocomposites exhibited superior electromagnetic absorption in both X and Ku bands, which was achieved by adjusting the RGO contents and matching thicknesses. Significantly, when the content of RGO was 7.4 wt%, the binary nanocomposites showed the optimal reflection loss of -73.9 dB at a thickness of 2.2 mm and broadest effective absorption bandwidth of 6.0 GHz (12.0–18.0 GHz) at a thin thickness of merely 2.0 mm. The enhanced electromagnetic absorption performance was primarily attributed to the multiple polarization effects, improved conduction loss caused by electron migration, and magnetic loss derived from ferromagnetic Co_0.5Zn_0.5Fe₂O₄ nanoparticles. Our results could provide inspiration for manufacturing graphene-based hybrid nanocomposites as high-efficient electromagnetic wave absorbers.     

Structure and magnetic properties of multi-morphological CoFe2O4/CoFe nanocomposites by one-step hydrothermal synthesis

Multi-morphological CoFe₂O₄/CoFe nanocomposites have been synthesized using a facile hydrothermal process. The effects of hydrazine hydrate amount during hydrothermal reaction on the structure and magnetic property of the specimens were studied. With increasing hydrazine hydrate amount, the CoFe₂O₄ transformed to CoFe and the morphology of the specimen changed from granular particles to faceted particles. The saturation magnetization monotonically increased and the coercivity monotonically decreased with increasing hydrazine hydrate amount. The magnetic interactions, determining the magnetic properties of the composites, result from the dominant dipole coupling and relative weak exchange coupling between CoFe₂O₄ and CoFe nanoparticles. The CoFe₂O₄/CoFe nanocomposite prepared with 2?mL hydrazine hydrate exhibited the optimal magnetic properties, with the saturation magnetization of 81?emu/g and coercivity of 636?Oe.     

Synthesis of hierarchical core-shell NiFe2O4@MnO2 composite microspheres decorated graphene nanosheet for enhanced microwave absorption performance

A ternary functional composite NiFe₂O₄@MnO₂@graphene was synthesized successfully via a facile method. The phase constitution, microstructures, morphologies and chemical compositions of the samples were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and X-ray photoelectron spectroscopy (XPS). It was observed that the NiFe₂O₄ nanoparticles were coated by hierarchically MnO₂ shells and distributed on the surface of graphene. Investigations of EM wave absorption indicated that NiFe₂O₄@MnO₂@ graphene composite has the strongest reflection loss of −47.4 dB at 7.4 GHz at the matching thickness of 3 mm, compared to NiFe₂O₄ and NiFe₂O₄@MnO₂, and its maximum absorption bandwidth (<−10 dB) is 4.3 GHz (from 5.1 to 9.4 GHz). The enhanced microwave absorption performance can be attributed to the hierarchical structure of MnO₂, void space between MnO₂ and graphene, and better impedance matching of ternary composite. The above results indicate that the novel hierarchical NiFe₂O₄@MnO₂@graphene composite, with intense absorption and wide absorption bandwidth, would be a promising absorber with less EM wave interference.     

Synthesis and strengthened microwave absorption properties of three-dimensional porous Fe3O4/graphene composite foam

The three-dimensional porous Fe₃O₄/graphene composite foam as a new kind of absorbing composite with electrical loss and magnetic loss was successfully synthesized by a facile method. Fe₃O₄ was evenly attached on structure of graphene sheets which overlapped with each other to form three-dimensional porous graphene foam. The results revealed that when the mass ratio of graphene oxide (GO) and Fe₃O₄ was 1:1, the Fe₃O₄/graphene composite foam possessed the best absorption properties: the minimum reflection loss was up to ??45.08?dB when the thickness was 2.5?mm and the bandwidth below ??10?dB was 6.7?GHz when the content of the composite foam absorbents was just 8%. The micron-sized three-dimensional porous structure provided more propagation paths, enhancing the energy conversion of incident electromagnetic waves. The addition of Fe₃O₄ contributed to improving the impedance matching performance and magnetic loss. The three-dimensional porous Fe₃O₄/graphene composite foam was a kind of high-efficiency wave absorber, providing a new idea for the development of microwave absorbing materials.     

Enhanced microwave absorption properties of Zn-substituted SrW-type hexaferrite composites in the Ku-band

Enhanced microwave absorption properties were successfully achievable from SrFe_2-xZn_xFe₁₆O₂₇ (SrFe_2-xZn_xW; x = 0.0, 0.5, 1.0, and 2.0) hexaferrite filler-epoxy resin matrix composites. The composite samples were fabricated with the filler volume fractions (V_f) of 30, 50, 70, and 90%. Compared with fully Zn-substituted SrZn₂W composite (x = 2.0), unsubstituted and partially Zn-substituted SrFe_2-xZn_xW (x = 0.0, 0.5, and 1.0) composites exhibited much higher real and imaginary parts of complex permittivity (ε_r), which is attributable to higher electron hopping between Fe²⁺ and Fe³⁺ ions, and also slightly higher real and imaginary parts of complex permeability (μ_r) due to higher saturation magnetization (M_s). Among all samples, a 2.8 mm-thick SrFe_1·5Zn_0·5W (x = 0.5) composite with the V_f of 90% exhibited the most appropriate for application in the region of 3.4–3.8 GHz, having the minimum reflection loss (RL_min) of ?46 dB at 3.6 GHz with the bandwidth of 0.43 GHz (3.38–3.81 GHz) below ?10 dB, while a 2.15 mm-thick SrFeZnW (x = 1.0) composite with the V_f of 70% showed the most appropriate for application in the region of 5.9–7.1 GHz, possessing the RL_min value of ?23.7 dB at 6.6 GHz with the bandwidth of 1.38 GHz (5.85–7.23 GHz) below ?10 dB. Consequently, partially Zn-substituted SrW-type hexaferrites are very promising microwave absorbers for 5G mobile communications in the Ku band (0.5–18 GHz).     

Grain growth kinetics in microwave sintered graphene platelets reinforced ZrO2/Al2O3 composites

The grain growth kinetics and mechanical properties of graphene platelets(GPLs) reinforced ZrO₂/Al₂O₃(ZTA) composites prepared by microwave sintering were investigated. The calculated grain growth kinetics exponent n indicated that the GPLs could accelerate the process of the Al₂O₃ columnar crystal growth. And the grain growth activation energy of the Al₂O₃ columnar crystal indicated that the grain growth activation energy of the GPLs doped ZTA composites is much higher than those of pure Al₂O₃ and ZTA in microwave sintering. The optimal mechanical properties were achieved with 0.4?vol% GPLs, whose relative density, Vickers hardness and fracture toughness were 98.76%, 18.10?GPa and 8.86?MPa?m^1/2, respectively. The toughening mechanisms were crack deflection, bridging, branching and pull-out of GPLs. The results suggested that GPLs-doped are good for the Al₂O₃ columnar crystal growth in the ZTA ceramic and have a potentially improvement for the fracture toughness of the ceramics.     

Synthesis of nanostructured material by mechanical milling and study on structural property modifications in Ni0.5Zn0.5Fe2O4

Mechanical milling induced structural property modifications in Ni_0.5Zn_0.5Fe₂O₄ spinel ferrite have been studied. We have observed two interesting phenomena (i) “temperature diffuse scattering” due to displacement of atoms from their mean position and (ii) appearance and gradual evolution of (4 2 0) plane in X-ray diffraction profiles and increase in average percentage disagreement between observed and calculated intensity ratios value, due to “preferred grain orientation.” Both these effects get prominent with milling time. The X-ray diffraction line intensity calculations revealed large B-site occupancy of Zn²⁺-ions, mainly due to modified synthesis procedure employed. The grain orientation factor increases from 10.6% to 18.1% on milling. It is found that milling has marked influence on various parameters: lattice constant, grain size, stress–strain, surface area and energy.     

Synthesis and magnetic properties of CoAlFe2O4 nanoparticles

Nanosized particles of CoAl_xFe_2-xO₄, where 0?≤?x?≤?2, were synthesized by the sol–gel combustion method and the magnetic properties of these compounds were investigated. According to X-ray diffractograms, the samples are single phase and the crystallite size is between 7 and 25?nm. The room temperature saturation magnetization of the samples was estimated from the cation distribution and ferromagnetic resonance spectra were used to determine the magnetocrystalline anisotropy. The results show that the saturation magnetization and the magnetocrystalline anisotropy vary over a wide range, from maxima of M_s =?0.42?MA/m and K?=?0.39?kJ/m³ for x?=?1.0 to minima of almost zero for x?≈?1.4, a result that could be useful for practical applications of these materials.     

Low temperature sintering of magnetic Ni0.5Co0.5Fe2O4 ceramics prepared from mechanochemically synthesized nanopowders

The effect of mechanochemichally synthesized nanoceramics Ni_0.5Co_0.5Fe₂O₄ (NCF) on the sintering process was studied. After 60?h of mechanochemichal treatment, the amount of formed ferrite phase reaches to about 70?vol%. From 60–100?h 10% increase in volume fraction of synthesized magnetic phase can be observed. Further increment in process time had no remarkable effect on the NCF phase formation. After 60?h, ceramic nanoparticle formation is directly reflected by TEM image and specific surface area (28?m²/g equivalent to 40?nm in diameter). The coercivity (Hc) shows a drastic diminution from 1996 to about 159?Oe by 60?h process time. Further milling treatment has no observable effect on the values of Hc. Additionally, the magnetization saturation (Ms) increases up to ~13?emu/g by 60?h mechanical milling of powders mixture. Thereafter from 60?h to 100?h, the Ms rapidly increased from 13 to 32?Oe. Finally, with continuing mechanochemichal process up to 130?h the Ms slightly diminished (~29?emu/g). Additionally, compared to synthesized powders the higher values of M_S (65?emu/g) and lower values of H_C (140?Oe) for sintered ceramic were detected. The low sintering temperature (1300?°C) for magnetic NCF sample prepared from nanoparticles may be caused by the high activity of nanoceramics.     

Achieving ultra-high electromagnetic wave absorption by anchoring Co0.33Ni0.33Mn0.33Fe2O4 nanoparticles on graphene sheets using microwave-assisted polyol method

The Co_0.33Ni_0.33Mn_0.33Fe₂O₄/graphene nanocomposite for electromagnetic wave absorption was successfully synthesized from metal chlorides solutions and graphite powder by a simple and rapid microwave-assisted polyol method via anchoring the Co_0.33Ni_0.33Mn_0.33Fe₂O₄ nanoparticles on the layered graphene sheets. The Fe³⁺, Co²⁺, Ni²⁺ and Mn²⁺ ions in the solutions were attracted by graphene oxide obtained from graphite and converted to the precursors Fe(OH)₃, Co(OH)₂, Ni(OH)₂, and Mn(OH)₂ under slightly alkaline conditions. After the transformations of the precursors to Co-Ni-Mn ferrites and conversion of graphene oxide to graphene under microwave irradiation at 170?°C in just 25?min, the Co_0.33Ni_0.33Mn_0.33Fe₂O₄/graphene nanocomposite was prepared. The composition and structure of the nanocomposite were characterized by X-ray diffraction (XRD), inductive coupled plasma emission spectroscopy (ICP), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (RS), transmission electron microscopy (TEM), etc. It was found that with the filling ratio of only 20?wt% and the thickness of 2.3?mm, the nanocomposite showed an ultra-wide effective absorption bandwidth (less than ?10?dB) of 8.48?GHz (from 9.52 to 18.00?GHz) with the minimum reflection loss of ??24.29?dB. Compared to pure graphene sheets, Co_0.33Ni_0.33Mn_0.33Fe₂O₄ nanoparticles and the counterparts reported in literature, the nanocomposite exhibited much better electromagnetic wave absorption, mainly attributed to strong wave attenuation, as a result of synergistic effects of dielectric loss, conductive loss and magnetic loss, and to good impedance matching. In view of its thin thickness, light weight and outstanding electromagnetic wave absorption property, the nanocomposite could be used as a very promising electromagnetic wave absorber.     

Crystal structure,microwave dielectric properties and low temperature sintering of (Al0.5Nb0.5)4+ co-substitution for Ti4+ of LiNb0.6Ti0.5O3 ceramics

The phase composition, microstructure, microwave dielectric properties of (Al_0.5Nb_0.5)⁴⁺ co-substitution for Ti site in LiNb_0.6Ti_0.5O₃ ceramics and the low temperature sintering behaviors of Li₂O-B₂O₃-SiO₂ (LBS) glass were systematically discussed. XRD patterns and EDS analysis result confirmed that single phase of Li_1.075Nb_0.625Ti_0.45O₃ solid solution was formed in all component. The increase of dielectric constant (ε_r) is ascribed to the improvement of bulk density. The restricted growth of grain has a negative influence on quality factor (Q×f) value. The τ_f value could be continuously shifted to near zero as the doping content increases. Great microwave dielectric properties were obtained in LiNb_0.6Ti_(0.5-x)(Al_0.5Nb_0.5)_xO₃ ceramics (x?=?0.10) when sintered at 1100?℃ for 2?h: ε_r =?70.34, Q×f =?5144?GHz, τ_f =?4.8?ppm/℃. The sintering aid, LBS glass, can effectively reduce the temperature and remain satisfied microwave performance. Excellent microwave dielectric properties for x?=?0.10 were obtained with 1.0?wt% glass: ε_r =?70.16, Q×f =?4153?GHz (at 4?GHz), τ_f =?-0.65?ppm/℃ when sintered at 925?℃ for 2?h.     

Characterization and low-temperature sintering of Ni0.5Zn0.5Fe2O4 nano-powders prepared by refluxing method

The as-prepared Ni_0.5Zn_0.5Fe₂O₄ powders fabricated directly from the solution of metal nitrates by the refluxing method were testified by the analysis of XRD, TEM, SAED and HRTEM. XRD pattern indicated that obtained Ni_0.5Zn_0.5Fe₂O₄ powders were single phase with spinel structure, TEM analysis showed that the powders with cubic shape were uniform in particle size of about 10-20 nm. Ceramics prepared by the as-synthesized Ni_0.5Zn_0.5Fe₂O₄ powders sintered at various temperatures between 950 °C and 1150 °C for 2 h were observed by SEM technique, which indicated that the Ni_0.5Zn_0.5Fe₂O₄ ferrites can almost be sintered to theoretic density at 1100 °C for 2 h, lower by at least about 200 °C compared with those ferrites prepared by the conventional oxide method. The relative magnetic loss tanδ/μ_i of the ceramic samples sintered at the temperature 1050 °C was measured to be of the order of 10^− 4-10^− 5 in the frequency range from 1 MHz to 10 MHz, and the threshold frequency of the ferrites was 77.2 MHz.     

Microstructure and microwave dielectric properties of Al2O3 added Li2ZnTi3O8 ceramics

Recently, the rapid development of advanced communication systems increasingly strongly demands high-performance microwave dielectric ceramics in microwave circuits. Among them, Li₂ZnTi₃O₈ ceramics have been one of the most widely investigated species, due to its high quality factor, moderate firing conditions and low cost. However, the dielectric constants of the already reported Li₂ZnTi₃O₈ ceramics are fixed in a narrow range, limiting their wider applications. To adjust the dielectric constant of the Li₂ZnTi₃O₈ based ceramics, in this work Li₂ZnTi₃O₈ ceramics added with different amounts of Al₂O₃ (0–8?wt%) were prepared by conventional solid-state reaction. The microstructure and microwave dielectric properties of the samples were investigated. Due to the addition of Al₂O₃, the sintering temperature of the ceramics would be increased somewhat. Some Al³⁺ ions could substitute for Ti⁴⁺ ions in Li₂ZnTi₃O₈, and the added Al₂O₃ would react with ZnO to produce a ZnAl₂O₄ phase accompanying with the formation of TiO₂ phase, which would inhibit the growth of Li₂ZnTi₃O₈ grains. The dielectric constant of the finally obtained ceramics would be reduced from 26.2 to 17.9, although the quality factors of the obtained ceramics would decrease somewhat and the temperature coefficient of resonant frequency would deviate further from zero.     

In situ growth of one-dimensional carbon-rich SiC nanowires in porous Sc2Si2O7 ceramics with excellent microwave absorption properties

For enhancing the absorption ability of dielectric and electromagnetic wave (EMW), C-rich SiC NWs /Sc₂Si₂O₇ ceramics are successfully fabricated through in-situ growth of SiC nanowires (NWs) into porous Sc₂Si₂O₇ ceramics by precursor infiltration and pyrolysis (PIP) at 1400?°C in Ar. SiC NWs are in-situ formed in the pore channels via a vapor-liquid-solid (VLS) mechanism, the relative complex permittivity increases notably with the content of absorber (C-rich SiC NWs), which tune the microstructure and dielectric property of C-rich SiC NWs/Sc₂Si₂O₇ ceramics. Meanwhile, the minimum reflection coefficient (RC) of C-rich SiC NWs/Sc₂Si₂O₇ ceramic decreases from ?9.5?dB to ??35.5?dB at 11?GHz with a thickness of 2.75?mm, and the effective absorption bandwidth (EAB) covers the whole X band (8.2–12.4?GHz) when the content of absorber is 24.5?wt%. The results indicate that Sc₂Si₂O₇ ceramics decorated with SiC NWs and nanosized carbon have a superior microwave-absorbing ability, which can be contributed to the Debye relaxation, interfacial polarization and conductivity loss enhanced by in-situ formed SiC NWs and nanosized carbon phases. The C-rich SiC NWs /Sc₂Si₂O₇ ceramics can be a promising microwave absorbing materials within a broad bandwidth.     

Direct and hybrid microwave solid state synthesis of CaCu3Ti4O12 ceramic: Microstructures and dielectric properties

CaCu₃Ti₄O₁₂ (CCTO) electroceramic possesses unusual giant dielectric permittivity up to ε?=?10⁴ at low frequency range and room temperature. CCTO dielectric properties strongly depend on its microstructure therefore it is essential to pay attention to the processing techniques which impact grain size and microstructure. In this work, direct and hybrid microwave solid state synthesis was specifically designed and used for the synthesis of CCTO. The microwave process was also compared to the conventional process which involves usual infrared heating. The structural (XRD) and microstructural (SEM) characterizations indicate that microwave synthesis is particularly efficient to get rapidly pure CCTO powder. The fully automated 915?MHz single-mode microwave cavity used for hybrid synthesis allows a perfect control of the temperature distribution and heating rate. Therefore hybrid microwave synthesis leads to a fine, mono-disperse and practically pure CCTO powder in the range of 300 – 500?nm. The advantages of the hybrid microwave heating method are discussed and compared to the conventional and direct microwave heating processes. From the powders synthesized by the different routes, dense compacts were sintered in air at 1050?°C in a conventional furnace. Microstructural characterizations reveal abnormal grain growth during sintering which levels dielectric properties. All exhibit a giant dielectric constant ε?>?10³ at room temperature which decreases drastically to ε?=?90 at 10?K. Those properties are discussed according to the well-established Internal Barrier Layer Capacitor (IBLC) model.     

Microwave-assisted one-pot synthesis of SnC2O4/graphene composite anode material for lithium-ion batteries

Currently, SnC₂O₄ is considered as one of the most promising anode materials for high-energy lithium-ion batteries (LIBs) because its charge capacity is higher than that of metal oxides. Herein, a facile microwave-assisted solvothermal method was employed to obtain SnC₂O₄/GO composites within only 30?min, which is time-efficient. The amount of SnC₂O₄ was increased to 95.3?wt% to improve the capacity of the composite. Pure SnC₂O₄ with a high specific surface area of 19.6?m² g^?1 without any other tin compound was used for fabrication. The SnC₂O₄/GO composite exhibited excellent electrochemical performance, with reversible discharge/charge capacity of 657/659?mA?h?g^?1 after 100 cycles at 0.2?A?g^?1. Furthermore, at high current densities of 1.0 and 2.0?A?g^?1, the SnC₂O₄/GO composite anode exhibited high reversible discharge/charge capacities of 553/552 and 418/414?mA?h?g^?1, respectively, after 200 cycles at room temperature. These improvements were likely obtained because SnC₂O₄ was well composited with graphene, which not only offered rapid electron transfer but also released the tension produced by the volumetric effect during repeated lithiation/delithiation. Cyclic voltammetry (CV) was also performed to further study the electrochemical reactions of SnC₂O₄/GO. The facile microwave-assisted solvothermal method used herein is considered as a highly efficient method to fabricate metal oxalate/graphene composites for use as anode materials in LIBs.     

Low-temperature synthesis of Bi2Fe4O9 nanoparticles via a hydrothermal method

Bi₂Fe₄O₉ (BFO) nanoparticles were successfully synthesized by a hydrothermal method at a temperature as low as 100 °C. The as-prepared powders, characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM) and physical property measurement system (PPMS), exhibited a pure BFO phase about 100 nm size with uniform sheet-like shape and exhibited an AF order at room temperature. It was found that high alkali concentration and alkali ion Na⁺ played a key role in the formation of BFO nanoparticles at a low temperature of 100 °C.     

Ni0.5Zn0.5Fe2O4 nanoparticles and their magnetic properties and adsorption of bovine serum albumin

Ni_0.5Zn_0.5Fe₂O₄ nanoparticles were synthesized by the facile citrate-gel process and the preliminary measurement for adsorption of bovine serum albumin (BSA) protein on these nanoparticles was carried out. The gel precursor and resultant nanoparticles were characterized by TG-DSC, FTIR, XRD, TEM and VSM techniques and the BSA adsorption on the nanoparticles was analyzed by UV spectrophotometer at room temperature. The results show that the single phase of spinel Ni_0.5Zn_0.5Fe₂O₄ is formed at 400 °C. With increasing calcination temperature from 400 to 700 °C, the average grain size increases from about 14 to 45 nm and consequently, the specific saturation magnetization of Ni_0.5Zn_0.5Fe₂O₄ nanoparticles increases from about 46 to 68 Am²/kg. The coercivity initially increases and then decreases with increasing calcination temperature, with a maximum value 9.2 kA/m at 500 °C. The as-prepared Ni_0.5Zn_0.5Fe₂O₄ nanoparticles exhibit a good adsorbing ability for BSA and the optimized adsorption is achieved for the Ni_0.5Zn_0.5Fe₂O₄ nanoparticles calcined at 500 °C with grain size about 24 nm.     

Microwave synthesis of magnetically separable ZnFe2O4-reduced graphene oxide for wastewater treatment

A magnetically separable ZnFe₂O₄-reduced graphene oxide (rGO) nano-composite was synthesised via a microwave method. Field emission scanning electron microscopy images of the nano-composite showed a uniform dispersion of nanoparticles on the rGO sheets. The performance of the nano-composite in wastewater treatment was assessed by observing the decomposition of methylene blue. The nano-composite showed excellent bifunctionality, i.e. adsorption and photocatalytic degradation of methylene blue, for up to five cycles of water treatment when illuminated with light from a halogen bulb. In contrast, water treatment with the nano-composite without illumination and the illuminated rGO, with no decoration of nanoparticles, diminished significantly after the first treatment. The reclamation of the ZnFe₂O₄-rGO nano-composite from treated water could be easily achieved by applying an external magnetic field.