Spinel ferrite magnetic adsorbents: Alternative future materials for water purification?

Ferrite nanoparticles (FNPs) have attracted a great interest due to their wide applications in several areas such as biomedical, wastewater treatment, catalyst and electronic device. This review focuses on the synthesis, characterisation and application of FNPs in electronic device with more emphasis on the recently published works. The most commonly used synthesis techniques along with their advantages and limitations are discussed. The available characterisation techniques and their application in electronic materials such as sensors and biosensors, energy storage, microwave device, electromagnetic interference shielding and high-density recording media are briefly reviewed.

Ferrite nanoparticles: Synthesis, characterisation and applications in electronic device

Application of spinel ferrite nanoparticles in water and wastewater treatment: A review

A novel one-dimensional (1D) Bi2O3 nanorod–Bi2WO6 nanosheet p–n junction photocatalyst was prepared by a three-step synthetic route. The obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and N2-sorption–desorption and Brunauer–Emmett–Teller (BET) surface area. Bi2O3 rods with the diameter of about 200 nm were obtained by calcining a Bi(OHC2O4)·2H2O precursor. Bi2WO6 nanosheets vertically grew on the Bi2O3 rods along the long axial direction. The photocatalytic activity required to degrade Rhodamine B (RhB) and phenol under solar/visible light by p–n junction of Bi2O3–Bi2WO6 nanorods was investigated. The results demonstrate that the novel Bi2O3–Bi2WO6 p–n heterostructures display higher photocatalytic activity than single Bi2O3 nanorods or Bi2WO6 flowers. The enhancement of the photocatalytic activity of the Bi2O3–Bi2WO6 p–n junction structures can be ascribed to strong visible light absorption and the effective separation of photogenerated electrons and holes by the internal electrostatic field in the junction region. More importantly, 1D p–n heterostructures made of ordered nanosheets are beneficial for the transport of photogenerated carriers and for increasing the rate of the photocatalytic reaction. This work could offer a new insight into the design and fabrication of advanced materials with heterojunction structures for photocatalytic applications and optoelectronic devices.

Novel one-dimensional Bi2O3–Bi2WO6 p–n hierarchical heterojunction with enhanced photocatalytic activity

The shortage of water resources and increasingly serious water pollution have driven the development of high-efficiency water treatment technology. Among a variety of technologies, adsorption is widely used in environmental remediation. As a class of typical adsorbents, metal oxides have been developed for a long time and continued to attract widespread attention, since they have unique physicochemical properties, including abundant surface active sites, high chemical stability, and adjustable shape and size. In this review, the basic principles of the adsorption process will be first elucidated, including affecting factors, evaluation index, adsorption mechanisms, and common kinetic and isotherm models. Then, the adsorption properties of several typical metal oxides, and key parameters affecting the adsorption performance such as particle/pore size, morphology, functionalization and modification, supports and calcination temperature will be discussed, as well as their application in the removal of various inorganic and organic contaminants. In addition, desorption and recycling of the spent adsorbent are summarized. Finally, the future development of metal oxide based adsorbents is also discussed.

Rational design, synthesis, adsorption principles and applications of metal oxide adsorbents: a review.

Herein, Fe-g-C3N4/Bi2WO6 Z-scheme heterojunction is elaborately designed to build a photo-Fenton system for the degradation of tetracycline (TC). In this study, the H2O2 decomposition performance of the Z-scheme heterojunction has been improved due to the doping of iron, improve photogenerated electrons transportability and facilitate spread of radicals, according to the efficacy analyses, and trapping experiment, ESR analysis as well as degradation pathways of TC. Moreover, DFT theoretical results suggest that the Z-scheme transfer route coupled with the generated photo–Fenton process builds a Z-scheme-charge-transfer platform for remarkable degradation of emerging pollutants, and the formation of Fe-N4 sites induces a spin polarization of the material and also introduces a defect state in the original forbidden band, which leads to extremely activity for the removal of TC in the photo-Fenton system. The study shows that 1O2 and •O2− are the main active species participating in the degradation process. 

Photo-Fenton degradation of tetracycline over Z-scheme Fe-g-C3N4/Bi2WO6 heterojunctions: Mechanism insight, degradation pathways and DFT calculation

Magnetically separable Ni0.6Fe2.4O4 nanoparticles as an effective adsorbent for dye removal: Synthesis and study on the kinetic and thermodynamic behaviors for dye adsorption

Enhanced photocatalytic performance in Bi2WO6/SnS heterostructures: Facile synthesis, influencing factors and mechanism of the photocatalytic process.

In this report, a novel photocatalyst based on Bi2WO6/Ag2S heterostructures was prepared by a 3-mercaptopropionic acid (MPA)-assisted route at room temperature. Compared to bare Bi2WO6 and Ag2S nanoparticles, the as-formed Bi2WO6/Ag2S heterostructures exhibit enhanced photocatalytic activity for the degradation of rhodamine B (Rh B) under visible-light irradiation. This kind of enhancement in the photocatalytic activity is considered to be the synergistic effects of both the effective electron-hole separation and expansion of the light-absorption range. The pH of the solution is of vital importance to the photocatalytic activity of the as-formed Bi2WO6/Ag2S heterostructures. Under low pH value, the photosensitization process is suppressed, while under higher pH value, the photosensitization process is favored. The mechanism of the photocatalytic process was proposed by the active-species-trapping experiments, indicating that the photogenerated holes (h(+)) play a crucial role in the degradation of Rh B under visible light. The enhanced photocatalytic performance of this heterostructure makes it a promising material for the treatment of dye-containing wastewater.

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Caihua Liu

Papers

Photo-Fenton degradation of tetracycline over Z-scheme Fe-g-C3N4/Bi2WO6 heterojunctions: Mechanism insight, degradation pathways and DFT calculation

Magnetically separable Ni0.6Fe2.4O4 nanoparticles as an effective adsorbent for dye removal: Synthesis and study on the kinetic and thermodynamic behaviors for dye adsorption

Enhanced photocatalytic performance in Bi2WO6/SnS heterostructures: Facile synthesis, influencing factors and mechanism of the photocatalytic process.

Facile Fabrication of Bi2WO6/Ag2S Heterostructure with Enhanced Visible-Light-Driven Photocatalytic Performances.

Solvent directed fabrication of Bi2WO6 nanostructures with different morphologies: Synthesis and their shape-dependent photocatalytic properties