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Magnetic Fe3O4/MnO2/TiO2/polypyrrole (PPy) heterostructure as adsorbent for adsorbing Mn7+ was synthesized by combining hydrothermal method and chemical oxidation method. The heterostructure was characterized by field‐emission scanning electron microscope, Fourier transform infrared spectroscopy, X‐ray diffraction, and vibrating sample magnetometer. Its saturation magnetization is 18.88 emu/g, so it is easy to separate it from the solution. The feasibility of Fe3O4/MnO2/TiO2/PPy heterostructure to remove Mn7+ was researched in detail. It is found that the optimal pH is 2. The initial adsorption rate can reach 4.60 mg/g min. At 288.15 K, the maximum equilibrium adsorption capacity is 202.8 mg/g. Adsorption kinetics follows a pseudo second order model, as well as is determined by through membrane diffusion processes. The Langmuir isotherm model is used to describe the adsorption isotherm behavior. Besides, thermodynamic parameters indicate spontaneous adsorption behavior, and entropy of the endothermic reaction increases. Finally, the cycle test results show that the adsorbent has better cycle performance, displaying broad application prospects. [ABSTRACT FROM AUTHOR]

Wastewater treatment has become a research hot issue in recent decade. Organic dyes as one of the main pollutants can change the water behavior. To deracinate the organic pollutants from wastewater, there are numerous methods have been taken into consideration. Photocatalysis is the promising strategy for the dye degradation with low cost, high efficiency, and environmental friendliness. Hence, a novel one‐dimensional (1D) magnetic Bi2Fe4O9/C@AgBr composite photocatalyst was prepared employing electrospinning, calcination, and deposition–precipitation methods. The morphology and composition of photocatalyst were characterized, as well as the photocatalytic activities of degrading methylene blue (MB) under visible light were investigated. And the results exhibited that the efficiency of Bi2Fe4O9/C@AgBr under visible light for 60 min is 97.4%. After three cycles, the degradation efficiency of MB could still reach 88.0%. Moreover, radical quenching experiment implicated superoxide radical anions as the primary active species responsible for photodegradation of MB. This work provides a new insight into the design of effective photocatalysts for practical application. [ABSTRACT FROM AUTHOR]

[Display omitted] Nowadays, ferrites/carbon fibers have attracted considerable attention as microwave absorption materials (MA) due to the synergistic effect between dielectric and magnetic loss. Herein, the ZnFe 2 O 4 /C fibers were fabricated via electrospinning and calcination methods, and then polypyrrole (PPy) successfully coated on the fibers via oxidative polymerization. The ZnFe 2 O 4 /C@PPy composites exhibit enhanced EM wave absorption performance with the loading of 25 wt%. The optimal reflection loss (RL) value is up to −66.34 dB (13.80 GHz) and effective absorption bandwidth (EAB) is 5.74 GHz (11.78–17.52 GHz) with a matching thickness of 1.93 mm. Besides, high-efficient absorption performance of the ZnFe 2 O 4 /C@PPy composites is mainly attributed to the dielectric loss and ideal impedance matching. This study reveals a novel approach to development of ferrites/carbon fibers coated with PPy, and the ZnFe 2 O 4 /C@PPy composites exhibit great potential application as the materials with high-efficient absorption properties. [ABSTRACT FROM AUTHOR]

[Display omitted] Metal-organic framework (MOF) materials have caused widespread concerns in the field of microwave absorption, due to the unique microstructure and electronic state. Herein, the CoZn/C@MoS 2 @polypyrrole (PPy) composites were prepared through MOF self-template method. The MoS 2 sheets and PPy shell incorporated for optimizing impedance matching of two-dimensional (2D) CoZn/C composites. The introduction of MoS 2 sheets and PPy shell endowed the composites with enhanced microwave absorption. The as-prepared CoZn/C@MoS 2 @PPy composites showed a minimum reflection loss (RL) of −49.18 dB with the thickness of 1.5 mm. In addition, the effective absorption bandwidth (EAB, RL values exceeding −10 dB) covered 4.56 GHz, which showed greater performances than CoZn/C composites under a lower thickness (<2 mm). This work not only provides a facile route for fabricating MOF-derived carbon-based composites as microwave absorbers, but also broadens the application of MOF materials. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, one-dimensional (1D) ZnFe 2 O 4 @carbon@MoS 2 /FeS 2 composites were synthesized by hydrothermal method, magnetic-field-induced distillation-precipitation polymerization and high-temperature carbonization. The structure, morphology, composition, magnetic performance and electromagnetic (EM) wave absorbing properties of the composites were systematically studied. The composites show strong microwave absorption (MA) capacity with a minimum reflection loss (RL min) value of −52.5 dB at 13.2 GHz, and have an effective absorption frequency range of 10.10–15.08 GHz with a bandwidth of 4.98 GHz when the thickness is 2.23 mm. It is expected that as-synthesized 1D ZnFe 2 O 4 @carbon@MoS 2 /FeS 2 composites can be a promising EM wave absorption material. [ABSTRACT FROM AUTHOR]

Recovery of uranium from strongly acidic solutions using magnetic nanoparticles as adsorbents is very important for sustainable nuclear energy, due to their superparamagnetic character and high adsorption efficiency for uranium. However, it is still a challenging task to develop magnetic nanoparticles for the removal of uranium from strongly acidic media, since most of the magnetic nanoparticles have poor acid resistance. Herein, superparamagnetic microspheres Fe3O4@SiO2/P(TRIM–VPA) bearing phosphine oxide groups have been developed successfully by distillation–precipitation polymerization of trimethylolpropane trimethacrylate (TRIM) and vinylphosphonic acid (VPA). Amazingly, Fe3O4@SiO2/P(TRIM–VPA) could still show a record-breaking maximum adsorption capacity (qmax) of 60.4 mg g−1 for uranium even in 4 mol L−1 of HNO3 with a good selectivity of 61.2% in strong HNO3 solution containing 11 coexisting ions. More importantly, the structure, uranium adsorption capacity and selectivity of the adsorbent in strong HNO3 media did not change obviously even after soaking in 4 mol L−1 of HNO3 for 24 h, indicating that the prepared magnetic adsorbent had excellent acid resistance. Also, the magnetic adsorbent could be recovered conveniently by magnetic force and reused at least six times without obvious decrease in adsorption capacity. The phosphine oxide groups were responsible for the good adsorption capacity for uranium in strong HNO3 solution, which was confirmed by XPS analysis and DFT method. To the best of our knowledge, this work reports the first example for effective extraction of uranium from strong HNO3 solution by employing functionalized magnetic nanoparticles as adsorbents. [ABSTRACT FROM AUTHOR]

Steel parts are a kind of high recovery value product for which de-rusting is the primary step in the recycling process. Laser cleaning is a popular and effective de-rusting technique at present. However, the rust on most end-of-life/used parts is very serious, and it is difficult for laser cleaning to remove it all. Therefore, a compound cleaning method was proposed in which molten salt was first used for the pretreatment of rust, followed by laser cleaning. It was shown that the rust layer after pretreatment was much easier to remove with low laser fluence. The cleaning efficiency could be improved by at least 1.34 times, and a cleaner surface without any damage could be obtained. This was the result of the inner-to-outer cleaning effect of molten salt. The penetration into the rust layer and the decomposition of the doped organics caused the contaminant layer to be destroyed in the interior and then peeled off sheet by sheet. The composition and structure analysis indicated that the remaining rust layer was oxidized, and it became looser after molten salt cleaning, which made it easier to clean. The application of molten salt to the cleaning of rusty parts will improve de-rusting efficiency and promote the development of de-rusting techniques effectively. It provides a feasible and high-efficiency choice for de-rusting. [ABSTRACT FROM AUTHOR]

A route to γ‐keto sulfones through a metal‐free reaction of cyclopropanols, DABCO ⋅ (SO2)2 and alkyl halides is described. This reaction occurs under mild conditions in the absence of any catalysts, additives, or oxidants. Various functional groups including as ester, amino, methoxy, bromo, trifluoromethyl, nitro and carbonyl are tolerated well in this transformation, and the corresponding γ‐keto sulfones are afforded in 35% to 95% yields. The proposed mechanism implies that this reaction proceeds through γ‐keto sulfinate intermediate generated in situ, which further undergoes nucleophilic substitution with alkyl halides leading to γ‐keto sulfones. [ABSTRACT FROM AUTHOR]