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Herein, a new type of super active nitrogen-doped biochar sheet (SNBC) was prepared by two-step pyrolysis and KOH chemical activation with melamine and cherry kernel powder as precursors of nitrogen and carbon source for removing Hg2+ from wastewater. The N2 adsorption/desorption and scanning electron microscope characterization revealed that the resulted SNBC under 600 °C calcination owned huge specific surface area of 2828 m2/g and plenty of well-developed micropores, and X-ray photoelectron spectroscopy and Fourier transform-infrared spectroscopy analysis testified the existence of functional groups containing N and O, which could provide adsorption sites for Hg2+. The SNBC-600 showed high adsorption capacity for Hg2+ even at low pH, and interfering cations had little effect on the adsorption. The adsorption process was rapid and dynamic data fit the pseudo-second-order dynamic model well. The maximum adsorption capacity of Hg2+ on SNBC-600 calculated by Langmuir model was 230 mg/g. After six times of reuse, the adsorption capacity still exceeded 200 mg/g, exhibiting good reusability. The designed microfiltration membrane device base on SNBC-600 could remove low concentration of Hg2+ effectively from solution. This study provided a simple and environment-friendly method for manufacturing nitrogen-doped biochar sheet, which was of great significance in the practical application of Hg2+ pollution treatment. [ABSTRACT FROM AUTHOR]

A rapid, sensitive, and selective fluorometric assay is described for the determination of chromium(VI) in real waters and living cells. The method is making use of nitrogen, phosphorus, and sulfur tri-doped carbon dots (NPS-CDs) which have absorption/emission maxima at 360/505 nm/nm. Cr(VI) has an absorption maximum at 350 nm and causes an inner filter effect (IFE) on the blue fluorescence of the NPS-CDs. The NPS-CDs were hydrothermally synthesized using p-aminobenzenesulfonic acid and tetrakis(hydroxymethyl)phosphonium chloride as precursors. The NPS-CDs were characterized by transmission electron microscopy, X-ray diffraction, and several spectroscopic methods. They are biocompatible and negligibly cytotoxic when tested with HeLa cells and MCF-7 cells even after 48 h of incubation. The NPS-CDs were used as fluorescent probes for Cr(VI). The detection limit is 0.23 μM (three times standard deviation versus slope), and the linear response covers the 1 to 500 μM chromate concentration range. The NPS-CDs were applied to the determination of Cr(VI) in real waters and living cells (HeLa and MCF-7) and gave satisfying results. [ABSTRACT FROM AUTHOR]

Flower-shaped organic-inorganic hybrid nanostructures, termed nanoflowers, have received considerable recent attention as they possess greatly enhanced activity, stability, durability, and even selectivity of entrapped organic biomolecules, which are much better than those from the conventional methods. They can be synthesized simply via co-incubation of organic and inorganic components in aqueous buffer at room temperature and yield hierarchical nanostructures with large surface-to-volume ratios, allowing for low-cost production by easy scale-up, as well as the high loading capacity of biomolecules without severe mass transfer limitations. Since a pioneering study reported on hybrid nanoflowers prepared with protein and copper sulfate, many other organic and inorganic components, which endow nanoflowers with diverse functionalities, have been employed. Thanks to these features, they have been applied in a diverse range of areas, including biosensors and biocatalysis. To highlight the progress of research on organic-inorganic hybrid nanoflowers, this review discusses their synthetic methods and mechanisms, structural and biological characteristics, as well as recent representative applications. Current challenges and future directions toward the design and development of multi-functional nanoflowers for their widespread utilization in biotechnology are also discussed. [ABSTRACT FROM AUTHOR]

The authors have immobilized nanowires made from zirconium glycerolate (ZrGly) on magnetite (Fe3O4) nanoparticles by applying a solvothermal growth process using metal-glycerolate as a precursor. The structure and the dissolutionrecrystallization mechanism of the resulting Fe3O4@ZrGly composite were investigated by attenuated total reflection-FTIR, energy-dispersive X-ray analysis, thermogravimetric analysis and solid-state cross polarization/magic angle spinning 13C NMR spectroscopy. The interaction between the zirconium glycerolate in Fe3O4@ZrGly and cis-diols leads to efficient adsorption of riboncleosides which then can be quantified by HPLC with UV detection. The sorbent was successfully applied to the selective enrichment of adenosine, cytidine, uridine and guanosine from spiked human urine samples. The detection limit of the method is in the range from 1.7 to 19 ng⋅mL-1 of nucleosides in spiked human urine, with relative standard deviations of lower than 12.4% and recoveries ranging from 90.6 to 113%. [ABSTRACT FROM AUTHOR]

LaO/polybenzoxazine composite was prepared through incorporating LaO into benzoxazine based on phenol and 4,4′-diaminodiphenyl methane (BB) to study the effect of LaO on the thermal stability of crosslinked polybenzoxazines. The ring-opening polymerization of BB benzoxazine was analyzed by DSC and measurement of viscosity. The structure and the thermal stability of BB polybenzoxazine were characterized by FTIR, TGA and DMA. The thermal degradation processes of polybenzoxazine were investigated using TGA-FTIR. The results showed that LaO could form coordination interaction with the nitrogen atoms of BB and thus promoted the polymerization of BB benzoxazine. The coordination interaction could not influence the volatilization of the amine degradation gases during the thermal degradation process of BB polybenzoxazine due to the amine structure existing in the chemical crosslinking network of polybenzoxazine and being stable. Furthermore, the coordination interaction weakened the C-N and C-C bonds in CH-NR-CH- of BB polybenzoxazine and thus accelerated the appearance and volatilization of the phenolic gases during the thermal degradation process, resulting in the decrease of the thermal stability and char yield at 800 °C of BB polybenzoxazine. [ABSTRACT FROM AUTHOR]

RHF/6-31G(d) and MP2/6-31G(d) calculations were carried out to study the stereoelectronic structure of 1-(1-trichlorogermylethyl)pyrrolidin-2-one with a pentacoordinated germanium atom. These results were compared with the X-ray diffraction structural analysis data. Upon formation of the Ge ← O coordination bond in this molecule, the electron density of all the atoms of the coordination polyhedron of the germanium atom, including the oxygen atom, increases, especially the axial chlorine atom, while the electron density of the germanium, nitrogen, and carbonyl group carbon atoms decreases. Different polarization of all three valence p-orbitals of each Cl atom of this molecule was established. Cl nuclear quadrupole resonance spectrum parameters were evaluated. The molecule also has stable form, in which the germanium atom is tetracoordinated. The total energy of this form is 2.7 kcal/mol higher than for the structure with a pentacoordinated germanium atom. [ABSTRACT FROM AUTHOR]

This contribution demonstrates a synthesis of comb polymer consisting of a poly(epichlorohydrin) (PECH) backbone and poly(oxyethylene methacrylate) side chains. Atom transfer radical polymerization (ATRP) was used to directly initiate the chlorine atoms of PECH macroinitiator. The structure of comb polymer was characterized by nuclear magnetic resonance (1H nuclear magnetic resonance) and Fourier transform infrared (FT-IR) spectroscopy, presenting the successful “grafting from” method using ATRP. The comb polymer was used as a polymer matrix for dissolving potassium iodide (KI) to prepare solid polymer electrolyte. FT-IR spectroscopy indicates that the potassium salts are dissolved in the polymeric matrix due to coordination interaction with the ether oxygens of graft copolymer. Differential scanning calorimetry showed that glass transition temperature ( T g) of polymer electrolytes continuously increased with increasing salt concentration up to 15 wt.%, mostly due to coordinative interactions between the potassium ions and the ether oxygens of polymer matrix. Ionic conductivity at room temperature increased with increasing salt concentrations up to 5 wt.% (maximum ionic conductivity ~3.7 × 10−5 S/cm), after which it gradually decreased. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbon dots (N-CDs) with a quantum yield of 41 ± 3% and excellent stability were prepared and are shown to be viable probes for the determination of ferric ions, which is a strong quencher of fluorescence. The absorption peak of the N-CDs is located at 325 nm. The optimal excitation and emission wavelengths of the N-CDs are 340 nm and 430 nm, respectively. The fluorometric response to Fe(III) is linear in the ranges between 1.0 and 21.0 μM and between 0.05 and 30.0 μM, and the limits of detection are 0.28 μM in case of colorimetry and 13.5 nM in case of fluorometry. Quenching by Fe(III) is mainly attributed to a combination of chelation (static quenching) and inner filter effect. The N-CDs also can be used as a new sort of fluorescent ink owing to the strong luminous performance and chemical inertness.The illustration for synthesis of the N-CDs and its applications for colorimetric and fluorescent detection of Fe3+ and fluorescent ink. [ABSTRACT FROM AUTHOR]