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Copper ferrite nanoparticles loaded on montmorillonite (MMT−CuFe2O4) were prepared by co‐precipitation method and applied as catalyst for activation of peroxymonosulfate (PMS) in degradation of reactive black 5 (RB5). The maximum removal efficiency of RB5 completely depends on the operating parameters and the highest removal percentage was obtained at MMT−CuFe2O4 dosage of 250 mg/L, PMS concentration of 4 mM, initial RB5 concentration of 50 mg/L and time of 15 min. The presence of anions such as Cl−, NO3−, HCO3−, and SO42− showed a significant limitation in the degradation of RB5 in the MMT−CuFe2O4/PMS system. Trapping experiments showed that ⋅OH and SO4⋅− radicals were involved in the catalytic degradation of RB5, however ⋅OH is the major specie in the catalysis system. Consecutive cycles were considered for testing the reusability of MMT−CuFe2O4; its results showed the stability of five consecutive cycles. The toxicity test was evaluated using Daphnia magna and the results illustrated a substantial drop in the toxicity of the solution treated. The significant reduction of TOC during RB5 degradation and the production of SO42−, NH4+ and NO3− confirm the proper progress of pollutant mineralization. The high catalytic performance of the catalyst in a short time compared to other removal systems emphasizes that MMT−CuFe2O4 can be suggested as a promising catalyst for the degradation of RB5 from aqueous solutions. [ABSTRACT FROM AUTHOR]

This work demonstrates the application of a Fe3O4/zeolitic imidazolate framework 67 (ZIF67) micromotor for improved catalytic degradation of organic pollutants. The micromotors were fabricated by simple adsorption of Fe3O4 nanoparticles on the surface of ZIF67 microparticles, which were synthesized by wet chemistry method. Both Fe3O4 and ZIF67 perform asymmetric decomposition of H2O2 to achieve bubble propulsion of the micromotors. The ferromagnetism of Fe3O4 enables easy directional control of the micromotor. The porous structure of ZIF67 benefits the enrichment of pollutant molecules around the micromotors, facilitating the efficient catalytic degradation. With intensified interaction between active sites and pollutant molecules due to self‐propelled motion and synergistic catalysis of iron in Fe3O4 and zinc ions in ZIF67, the micromotors exhibit enhanced degradation activity of methylene blue as compared to the pure Fe3O4 or ZIF67 counterparts without autonomous motion. This research can be extended to developing other metal‐organic frameworks (MOF)‐integrated micromotors for the environmental applications. [ABSTRACT FROM AUTHOR]

Supported metallic nanoparticles (NPs) have recently become a promising candidate for the degradation of environmental pollutants. In this work, we report the fabrication of highly catalytically active, surfactant‐free interconnected Au nanostructures directly on filter paper. The width of nanostructures is only a few nanometers and they contain high concentration of low‐coordination atoms. Our approach involves the immersion and evaporation of Au precursor solution on the filter paper and its subsequent reduction. This approach generates filter paper‐based gold substrates (FPGS) not only in a simple and straightforward fashion that can be executed in a matter of minutes but can also be easily scaled up for large‐scale production. Owing to their surfactant‐free nature, FPGS are well suited for the degradation of both cationic and anionic dyes by providing large unhindered surface for dye adsorption. The FPGS were able to completely degrade methyl orange (MO) and methylene blue (MB) dyes and also showed excellent reusability and stability. [ABSTRACT FROM AUTHOR]

This paper details the selective optical, fluorescent and electrochemical detection of Zn2+ among various divalent metal ions in aqueous solution by the green synthesized silver nanoparticles (AgNP) using the fresh extract of Myristica fragrans (MF) with the aid of microwave energy. The synthesized silver nanoparticles stabilized with MF were analysed using UV-vis., Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. Due to the effective complexation between silver nanoparticles and metal ions, absorbance of AgNP-MF diminished with increasing concentration of Zn2+. This is visually identified through the color changes. Fluorescent sensing studies involved the changes in fluorescent intensity of AgNP-MF in the presence of Zn2+. Electrochemical sensing of Zn2+ was carried through cyclic and differential pulse voltammetric techniques using AgNP-MF modified platinum electrode (AgNP-MF􀀀 Pt). The developed electrochemical sensor showed a limit of detection (LOD) of 0.6148 μM and its good sensing ability was checked for the detection of Zn2+ in environmental water samples. Recoveries of Zn2+ in the various real water samples were obtained in the range from 100.2% to 100.6%. The multifunctional utility of the AgNP-MF as a catalyst towards the reduction of two environmentally toxic contaminants such as o/p-nitroanilines through NaBH4 was also evaluated. The complete degradations were achieved within few minutes and the reactions followed pseudo first order kinetics. The effect of catalytic dosage on the rate of reduction reactions was also studied. [ABSTRACT FROM AUTHOR]

Abstract: Yolk‐shell structured Fe3O4@copper silicates (FCSs) were prepared and applied for catalytic degradation of methylene blue (MB). The samples were characterized by SEM, TEM, XRD, FTIR, XPS and N2 sorption isotherms. FCS prepared with trisodium citrate, named FtCS, presented better catalytic performance than FcCS (FCS prepared with cetyltrimethylammonium bromide (CTAB)) and other catalysts reported recently. Four successive runs of FtCS along with the negligible Cu2+ leaching (6 ppm) certified that the composite was stable. The results showed that copper component ≡Cu(II) in FtCS was the main active phase which promoted H2O2 to produce hydroxyl radicles (HO⋅) resulting in the MB decomposition. [ABSTRACT FROM AUTHOR]