A Generalized Method for the Synthesis of Carbon-Encapsulated Fe₃O₄ Composites and Its Application in Water Treatment

In this paper, a simple and environmentally friendly method was developed for the preparation of highly stable C@Fe3O4 composites with controllable morphologies using sodium alginate as the carbon source and the easily obtained α-Fe2O3 as the precursors. The morphologies of the as-prepared C@Fe3O4 composites, inherited from their corresponding precursors of α-Fe2O3, survived from the annealing treatments, were characterized by the field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The C@Fe3O4 composites resisted to oxidation, acidification and aggregation, exhibiting porous structures and ferromagnetic properties at room temperature. Moreover, the adsorption performance of the C@Fe3O4 composites was evaluated by absorbing MB (methylene blue) in liquid environment. Experiments indicated that the C@Fe3O4 composites exhibited highly enhanced adsorption capacities and efficiencies as compared with their corresponding precursors of α-Fe2O3. This generalized method for the synthesis of C@Fe3O4 composites provides promising applications for the highly efficient removal of MB from industrial effluents

Schiff Base Compounds as Fluorescent Probes for the Highly Sensitive and Selective Detection of Al³⁺ Ions

Two new Schiff base fluorescent probes (L and S) were designed for selectively detecting Al3+ ions in aqueous medium. Structural characterization of the purely synthesized compounds was acquired by IR, 1H NMR and 13C NMR. Moreover, their photochromic and fluorescent behaviors have been investigated systematically by UV–Vis absorption and fluorescence spectra. The two probes have both high selectivity and sensitivity toward Al3+ ions in aqueous medium. The 2:1 stoichiometry between the Al3+ and probes was verified by Job’s plot. Moreover, the limits of detection (LOD) for Al3+ by L and S were 1.98 × 10−8 and 4.79 × 10−8 mol/L, respectively, which was much lower than most previously reported probes. The possible recognition mechanism was that the metal ions would complex with Schiff base probes because of the prevalence of the species optimal for complex formation, inhibiting the structural isomerization of conjugated double bonds (-C=N-), inhibiting the proton transfer process in the excited state of the molecules and resulting in changes of its color and fluorescence behavior. Furthermore, the probes will have potential applications for selectively, detecting Al3+ ions in the environmental system with high accuracy and providing a new strategy for the design and synthesis of multi-functional sensors

One-Dimensional Shaving-like BiVO₄ Nanobelts: Synthesis, Characterization and Photocatalytic Activity with Methylene Blue

One-dimensional shaving-like BiVO4 nanobelts were successfully synthesized via the oxide hydrothermal method (OHS), using V2O5 and Bi2O3 as raw materials and PEG 10000 (polyethylene glycol 10000) as a template. Multiple techniques, including XRD, SEM, TEM, HRTEM, UV–Vis, XPS, and photoelectrochemical measurements, were applied to characterize the obtained materials. The thickness of the BiVO4 nanobelt was approximately 10 nm, while the width was approximately 500 nm. EIS results showed that visible-light illumination caused the photogenerated charge of the BiVO4 nanobelts to have a faster transfer and a higher separation efficiency. Photocatalytic experiments indicated that with BiVO4 nanobelts as a catalyst, the degradation rate of MB (methylene blue) was close to 92.4%, and it disintegrated after two hours. Moreover, the pseudo-first-order kinetic model can be used to describe the photodecomposition reaction of MB catalysed by BiVO4 nanobelts. And this excellent photocatalytic activity of the shaving-like BiVO4 nanobelts may be related to their special morphology, narrow band gap (~2.19 eV), faster transfer and the separation efficiency of the photogenerated charge, leading to strong absorption in the visible region and improving the separation of the photogenerated electron–hole pairs. These novel monoclinic BiVO4 nanobelts exhibited great photocatalytic activity and are thus a promising candidate for application in visible-light-responsive photocatalysts

Antioxidant Interactions between S-allyl-L-cysteine and Polyphenols Using Interaction Index and Isobolographic Analysis

This work aims to study the antioxidant interactions between S-allyl-L-cysteine (SAC) and six natural polyphenols (quercetin, caffeic acid, sinapic acid, catechin, ferulic acid, and 3,4-dihydroxybenzoic acid) through the measurement of free-radical-scavenging activity of 1,1-diphenyl- 2-picryl-hydrazyl (DPPH), the radical-cation-scavenging activity of 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and reducing power. Among the six natural polyphenols, caffeic acid showed the strongest synergistic effect with SAC according to DPPH and reducing power assays. Further investigations based on the results of interaction index and isobologram analysis showed that the antioxidant activity (DPPH, ABTS, and reducing power) of the combination of caffeic acid with SAC presented an increase with the raising of their individual concentrations in their mixture and along with a dose–response manner. The best synergistic effect between caffeic acid and SAC based on DPPH, ABTS, and reducing power assays were observed at the ratio of 1:20, 1:35, and 1:70, respectively. The excellent synergic antioxidant activity of the combination of caffeic acid with SAC in our study suggests SAC has a more broad and effective application prospects in food field

HF-Free Synthesis of Nanoscale Metal–Organic Framework NMIL-100(Fe) as an Efficient Dye Adsorbent

A hydrofluoric acid (HF)-free solvothermal method was used to synthesize nanoscale metal–organic framework NMIL-100­(Fe), which exhibited comparable physicochemical properties as those prepared by traditional methods, but with a mild and environmentally benign synthesis condition. XRD, TGA, N₂ adsorption, FT-IR, SEM, and TEM were employed to characterize the as-prepared NMIL-100­(Fe), which was further applied as an effective adsorbent for dye adsorption, including two cationic dyes, rhodamine 6G (R6G) and rhodamine B (RB), and an anionic reactive red 120 (RR 120) with high adsorption efficiencies and capacities. The adsorption process can be well described by pseudo-second-order kinetic model and Langmuir isotherm model. Hydrogen bonding and electrostatic interaction were revealed for the adsorption of the two cationic dyes and one anionic dye onto NMIL-100­(Fe), respectively, as investigated by mechanism studies. Thermodynamic analyses indicate that adsorption processes for cationic and anionic dyes are entropy-driven endothermic and enthalpy-driven exothermic processes, respectively. This environmental-benign synthetic strategy for NMIL-100­(Fe), as well as its high adsorption efficiency and capacity, might be used for the fabrication of other nanoscale metal–organic frameworks, and the potential applications of NMIL-100­(Fe) in real wastewater treatment

Removal of U(VI) from Aqueous Solution by Amino Functionalized Flake Graphite Prepared by Plasma Treatment

Flake graphite (FG) with high uranium­(VI) entrapment efficiency was successfully fabricated via a simple and efficient nonthermal plasma treatment method. FG was modified with −NH₂ functional groups through nonthermal plasma with different treatment times under vacuum conditions. The modified FG samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FT-IR spectra), thermogravimetric analysis (TGA), BET surface area measurements, and zeta potential. FG samples with different treatment times are used as contrast adsorbents for U­(VI) entrapment. The adsorption experiments show that the modified FG has higher high U­(VI) entrapment efficiency than others, and longer treatment time results in higher efficiency, demonstrating that the plasma treatment can greatly increase the active sites of FG samples and lead to the successful grafting of −NH₂ on FG surface. The −NH₂ modified FG with 2 h treatment time shows the highest adsorption capacity with 140.68 mg·g^–1 among the five samples at 333.15 K. Thermodynamic studies reveal that the U­(VI) entrapment process is spontaneous and entropy-driven endothermic. XPS studies reveal that the adsorption mechanism for U­(VI) entrapment is achieved through the complexation of U­(VI) with both −NH₂ and phenolic hydroxyl group on the surface of modified FG. Moreover, desorption studies exhibit that PTFG-4 can be used repeatedly and adsorption capacity only shows slight decrease after five cycles. Thus, it can be concluded that the nonthermal plasma treatment can be used as an effective method for the fabrication of adsorbents with great adsorption performance for heavy metals entrapment

Electronic supplementary material for the synthesis of [60]fullerene oxides by plasma jet from Highly efficient synthesis of [60]fullerene oxides by plasma jet

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