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Activated sericite was used as a solid matrix for control over the size of iron oxide nanoparticles (NPs). The activation of sericite was achieved by undergoing thermal, acid and salt treatments. Different weight ratios (w.r.) of iron oxide to activated sericite were prepared by varying the amount of iron oxide. X-ray diffraction (XRD) patterns illustrated a decrease in the intensity of sericite peaks by increasing the amount of iron oxide. High resolution-transmission electron microscopy (HR-TEM) analysis showed the formation of highly distributed quasi-spherical iron oxide NPs with average diameter of about 3.56–7.78 nm. The formation of mesoporous iron oxide NPs on the surface and edge of the activated sericite surface were also observed under Field emission scanning electron microscopy (FESEM). Vibration sample magnetometer (VSM) measurement revealed the nanocomposites (NCs) with saturation magnetization of about 2.17–8.12 emu·g−1. Brunauer-Emmett-Teller (BET) surface area analysis revealed the specific surface area of NCs between 79.4 and 161.5 m2·g−1. Fourier transform infrared (FTIR) spectra showed non-bond chemical interaction between the iron oxide and rigid silicate layers. Ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy confirms that the material has band gap energy of about 2.55 eV. The NC with w.r. of 1:3 (iron oxide to activated sericite) showed the best performance with high specific surface area and sufficient magnetization for easy magnetic separation. The selected NC showed maximum removal efficiency over 99% for methylene blue and crystal violet dyes within 20 min.

Activated sericite was used as a solid matrix for control over the size of iron oxide nanoparticles (NPs). The activation of sericite was achieved by undergoing thermal, acid and salt treatments. Different weight ratios (w.r.) of iron oxide to activated sericite were prepared by varying the amount of iron oxide. X-ray diffraction (XRD) patterns illustrated a decrease in the intensity of sericite peaks by increasing the amount of iron oxide. High resolution-transmission electron microscopy (HR-TEM) analysis showed the formation of highly distributed quasi-spherical iron oxide NPs with average diameter of about 3.56–7.78 nm. The formation of mesoporous iron oxide NPs on the surface and edge of the activated sericite surface were also observed under Field emission scanning electron microscopy (FESEM). Vibration sample magnetometer (VSM) measurement revealed the nanocomposites (NCs) with saturation magnetization of about 2.17–8.12 emu·g−1. Brunauer-Emmett-Teller (BET) surface area analysis revealed the specific surface area of NCs between 79.4 and 161.5 m2·g−1. Fourier transform infrared (FTIR) spectra showed non-bond chemical interaction between the iron oxide and rigid silicate layers. Ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy confirms that the material has band gap energy of about 2.55 eV. The NC with w.r. of 1:3 (iron oxide to activated sericite) showed the best performance with high specific surface area and sufficient magnetization for easy magnetic separation. The selected NC showed maximum removal efficiency over 99% for methylene blue and crystal violet dyes within 20 min.

A massive release of harmful substances especially heavy metal ions and dyes to the environment has been a major concern due to many people disregards the proper protocols in the waste management. The freshwater supplies are threatened and huge discharge of pollutants result from various anthropogenic activities may pose a major threat to the living organisms and negatively affect the ecosystem stability. This article reviews the development of magnetic iron oxide nanocomposites for removal of heavy metal ions and dyes from water. The highlight will be focused on current research activities for controlled size and dispersion of magnetic iron oxide nanoparticles within solid matrices including zeolites, silica, clays, carbon, activated carbon, graphene and graphene oxide. The magnetic properties of the nanocomposites will be evaluated to determine whether they possessed sufficient magnetization for easy separation by an external magnet. The unique features of the synthesized materials will be investigated along with their application in the removal of heavy metal ions and dyes. The advantages and limitations of the magnetic nanocomposites will be highlighted to determine their adsorption ability. The effect of various parameters such as pH, contaminants concentration, adsorbent dosage, contact time and temperature will be summarized to identify the best condition for effective pollutants removal.

A massive release of harmful substances especially heavy metal ions and dyes to the environment has been a major concern due to many people disregards the proper protocols in the waste management. The freshwater supplies are threatened and huge discharge of pollutants result from various anthropogenic activities may pose a major threat to the living organisms and negatively affect the ecosystem stability. This article reviews the development of magnetic iron oxide nanocomposites for removal of heavy metal ions and dyes from water. The highlight will be focused on current research activities for controlled size and dispersion of magnetic iron oxide nanoparticles within solid matrices including zeolites, silica, clays, carbon, activated carbon, graphene and graphene oxide. The magnetic properties of the nanocomposites will be evaluated to determine whether they possessed sufficient magnetization for easy separation by an external magnet. The unique features of the synthesized materials will be investigated along with their application in the removal of heavy metal ions and dyes. The advantages and limitations of the magnetic nanocomposites will be highlighted to determine their adsorption ability. The effect of various parameters such as pH, contaminants concentration, adsorbent dosage, contact time and temperature will be summarized to identify the best condition for effective pollutants removal.

This paper presents a green, facile and rapid method to prepare magnetite/zeolite-nanocomposites (NCs) in one step procedure at ambient temperature. The powder X-ray diffraction (PXRD) pattern of iron oxide nanoparticles (NPs) with the sole zeolite showed the broadening of zeolite peaks attributed to the incorporation of Fe3O4. Field-emission scanning electron microscopy (FESEM) analysis depicted that the Fe3O4‒NPs were formed on the surface of porous zeolite framework. Transmission electron microscopy (TEM) analysis displayed the Fe3O4 nanoparticles (NPs) were mostly in spherical shape with a mean diameter and standard deviation of 2.40 ± 0.41 nm. The selected-area electron diffraction (SAED) pattern confirmed the presence of cubic Fe3O4 phase. The vibrating sample magnetometer (VSM) results indicated the as-synthesized sample has a saturation magnetization of around 6.52 emu g−1. The magnetite/zeolite-NCs can be considered as a low-cost alternative catalyst for oxygen reduction reaction (ORR) process. The electrochemical measurement showed that the performance of magnetite/zeolite-NCs towards the ORR increased as the scan rate increased from 20 mV s−1 to 500 mV s−1. The ORR is a diffusion-controlled process in the alkaline medium.

This paper presents a green, facile and rapid method to prepare magnetite/zeolite-nanocomposites (NCs) in one step procedure at ambient temperature. The powder X-ray diffraction (PXRD) pattern of iron oxide nanoparticles (NPs) with the sole zeolite showed the broadening of zeolite peaks attributed to the incorporation of Fe3O4. Field-emission scanning electron microscopy (FESEM) analysis depicted that the Fe3O4‒NPs were formed on the surface of porous zeolite framework. Transmission electron microscopy (TEM) analysis displayed the Fe3O4 nanoparticles (NPs) were mostly in spherical shape with a mean diameter and standard deviation of 2.40 ± 0.41 nm. The selected-area electron diffraction (SAED) pattern confirmed the presence of cubic Fe3O4 phase. The vibrating sample magnetometer (VSM) results indicated the as-synthesized sample has a saturation magnetization of around 6.52 emu g−1. The magnetite/zeolite-NCs can be considered as a low-cost alternative catalyst for oxygen reduction reaction (ORR) process. The electrochemical measurement showed that the performance of magnetite/zeolite-NCs towards the ORR increased as the scan rate increased from 20 mV s−1 to 500 mV s−1. The ORR is a diffusion-controlled process in the alkaline medium.

Synthesis of nanostructured semiconductor materials from various single source precursors has been massively explored for potential applications in modern technology. Thermal decomposition method has been employed to prepare nanoparticles zinc sulphide from zinc N-ethyl cyclohexyl dithiocarbamate precursor. Effect of heat treatment at different calcination duration on the structural, morphological, compositional and band gap properties of zinc sulphide were investigated. The obtained samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. XRD showed the precursor was decomposed to hexagonal zinc sulphide after 2–6 h of calcination duration at 400 °C. The sizes of zinc sulphide (ZnS) nanoparticles obtained from TEM analysis were about 6–11 nm. The existence of the hexagonal ZnS phase is not affected by the calcination duration, while only a slight difference in the crystallinity and crystallite size of ZnS is observed from XRD analysis. EDX analyses reveal that the as-prepared ZnS nanoparticles have an approximate composition of Zn and S close to 1:1, giving a possible composition of ZnS. Besides, direct band gap energy of ZnS was found to be around 3.78–3.95 eV.

Synthesis of nanostructured semiconductor materials from various single source precursors has been massively explored for potential applications in modern technology. Thermal decomposition method has been employed to prepare nanoparticles zinc sulphide from zinc N-ethyl cyclohexyl dithiocarbamate precursor. Effect of heat treatment at different calcination duration on the structural, morphological, compositional and band gap properties of zinc sulphide were investigated. The obtained samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. XRD showed the precursor was decomposed to hexagonal zinc sulphide after 2–6 h of calcination duration at 400 °C. The sizes of zinc sulphide (ZnS) nanoparticles obtained from TEM analysis were about 6–11 nm. The existence of the hexagonal ZnS phase is not affected by the calcination duration, while only a slight difference in the crystallinity and crystallite size of ZnS is observed from XRD analysis. EDX analyses reveal that the as-prepared ZnS nanoparticles have an approximate composition of Zn and S close to 1:1, giving a possible composition of ZnS. Besides, direct band gap energy of ZnS was found to be around 3.78–3.95 eV.