Synergistic Photocatalytic-Adsorption Removal of Basic Magenta Effect of AgZnO/Polyoxometalates Nanocomposites.

The bifunctional photocatalytic-adsorbent AgZnO/polyoxometalates (AgZnO/POMs) nanocomposites were synthesized by combining AgZnO hybrid nanoparticles and polyoxometalates [Cu(L)2(H2O)]H2[Cu(L)2(P2Mo5O23)]⋅4H2O (HL = C6H6N2O) into nanostructures via a sonochemical method. Transmission electron microscopy (TEM) indicated that AgZnO/POMs nanocomposites were uniform with narrow particle size distribution and without agglomeration. X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the nanostructure and composition of AgZnO/POMs nanocomposites. The ultraviolet-visible spectra (UV-Vis) and photoluminescence spectra (PL) confirmed excellent optical properties of the AgZnO/POMs nanocomposites. 94.13% ± 0.61 of basic magenta (BM) in aqueous solution could be removed using the AgZnO/POMs nanocomposites through adsorption and photocatalysis. The kinetic analysis showed that both the adsorption and photocatalysis process conform to pseudo-second-order kinetics. In addition, the removal rate of AgZnO/POMs nanocomposites was found to be almost unchanged after 5 cycles of use. The bifunctional photocatalytic-adsorbent AgZnO/POMs nanocomposites with high stability and cycling performance have broad application prospects in the treatment of refractory organic dye wastewater containing triphenylmethane.

Synthesis, Characterization and Dye Removal Behavior of Core-Shell-Shell Fe3O4/Ag/Polyoxometalates Ternary Nanocomposites.

The ternary nanocomposites Fe3O4/Ag/polyoxometalates (Fe3O4/Ag/POMs) with core-shell-core nanostructure were synthesized by coating [Cu(C6H6N2O)2(H2O)]H2[Cu(C6H6N2O)2(P2Mo5O23)]·4H2O polyoxometalates on the surface of Fe3O4/Ag (core-shell) nanoparticles. The transmission electron microscopy/high resolution transmission electron microscopy (HR-TEM) and X-ray powder diffraction (XRD) analyses show that the Fe3O4/Ag/POMs ternary nanocomposites reveal a core-shell-core nanostructure, good dispersibility, and high crystallinity. The vibrating sample magnetometer (VSM) and physical property measurement system (PPMS) demonstrated the good magnetic properties and superparamagnetic behavior of the nanocomposites at 300 K. The UV-vis spectroscopy displayed the broadband absorption of the Fe3O4/Ag/POMs with the maximum surface plasmon resonance of Ag nanostructure around 420 nm. The dye removal capacity of Fe3O4/Ag/POMs was investigated using methylene blue (MB) as a probe. Through adsorption and photocatalysis, the nanocomposites could quickly remove MB with a removal efficiency of 98.7% under the irradiation of visible light at room temperature. The removal efficiency was still as high as 97.5% even after six runs by magnetic separation of photocatalytic adsorbents after processing, indicating the reusability and high stability of the nanocomposites. These Fe3O4/Ag/POMs photocatalytic adsorbents with magnetic properties will hopefully become a functional material for wastewater treatment in the future.

A polyoxometalate-modified magnetic nanocomposite: a promising antibacterial material for water treatment.

In this work, polyoxometalate-modified magnetic nanocomposite Fe3O4@PDA@POM was prepared by coating [Cu(HL)4]2[P2Mo5O23]2·8H2O (POM, L = 2-aminopyridine) on the surface of a preassembled polydopamine (PDA)-capped carboxyl-functionalized Fe3O4 magnetic microspheres. Our studies on Gram negative bacterium Escherichia coli (E. coli) indicated that owing to the collective effect between preassembled Fe3O4 and POM, the Fe3O4@PDA@POM nanocomposite loaded on nickel foam exhibited outstanding antibacterial activity and reusability, and even after 6 cycles it has a high antibacterial capability of ca. 90%. Further extension of this investigation towards Gram positive bacterium Staphylococcus albus (S. aureus) demonstrated a similar toxicity pattern, confirming the potential applications of this material for water treatment in biochemical processes. The antibacterial mechanism of the Fe3O4@PDA@POM nanocomposite was further investigated by taking E. coli as a model microorganism.

Multifunctional Magnetic-Fluorescent Nanoparticle: Fabrication, Bioimaging, and Potential Antibacterial Applications.

Magnetic-fluorescent nanoparticles integrating imaging and therapeutic capabilities have unparalleled advantages in the biomedical applications. Apart from the dual ability of unique biomolecular fluorescent recognition and magnetic modes, the nanoparticle also endows combined effective therapies with high physiological stability, long-term imaging, rapid response time, and excellent circulation ability. Herein, we developed a carboxyl-functionalized magnetic nanoparticle that was further functionalized by polydopamine (PDA) and Schiff base ligand (3-aminopyridine-2-carboxaldehyde N(4)-methylthiosemicarbazone, HL) to form multilayered coating single nanoparticles (Fe3O4@PDA@HL). Our work showed that the aggregation-induced emission (AIE) effect could be produced by embedding In3+ into the Fe3O4@PDA@HL nanostructure, which offered a new opportunity for utilization as a fluorescent detection and therapeutic platform. Cellular fluorescent imaging experiments provided bacterial cell biodistribution, demonstrating their excellent luminescent performance, magnetic aggregation, and separation capability. We simultaneously confirmed that the synergistic antibacterial effect was closely related to both Fe3O4@PDA@HL and In3+, leading to the disruption of membrane integrity and the leakage of intracellular components, thus inducing bacterial death. This approach presented in our work could promote the development of future bioimaging and clinical therapy applications.