Efficient extraction of uranium from aqueous solution using an amino-functionalized magnetic titanate nanotubes.

In this paper, titanate nanotubes/cobalt ferrite/tetraethylenepentamine (TNTs/CoFe2O4/TEPA) adsorbents were prepared for the adsorption of uranium (VI) from the solution. Its morphology was observed by transmission electron microscopy (TEM) and exhibited the uniform well tubular structure. TNTs/CoFe2O4/TEPA composites were easily separated from solution by an external magnetic field. The removal of uranium (VI) from aqueous solution (ppm level) and simulated seawater (ppb level) were investigated by the TNTs/CoFe2O4/TEPA composites. Batch adsorption experiments were conducted to determine the effect of varying pH, contact time, and reaction temperature. The best fit for uranium (VI) adsorption was obtained with the Langmuir model, and the highest adsorption of TNTs/CoFe2O4/TEPA composites reached 509.89 mg-U/g-adsorbent at pH 6. From an investigation of the adsorption by XRD, FTIR and XPS, it is suggested that the surface complexation and cation exchange were the main adsorption mechanism. In addition, TNTs/CoFe2O4/TEPA composites maintained good adsorption properties after five sorption-desorption cycles. Therefore, we conclude that the adsorbents are promising materials for the removal of uranium (VI) from aqueous solutions.

Impact of addition sheet-like cobalt in ionic liquids mixture to detect oxygen.

The incorporation of 1-alkyl-3-methylimidazolium hexafluorophosphate (AMIMPF6) and 1-vinlyimidazole (VIM) firstly served as electrolyte for oxygen sensor, which remarkably promoted response current. Moreover, the sheet-like structure of cobalt was deposited onto the surface of C@TiC nanowire (Co/C), which endowed the imidazole-based ionic liquid electrolyte with plentiful active sites and fast electron transfer rate for oxygen reduction reaction. There was little literature about the integration of AMIMPF6, VIM and Co/C as the electrolyte for oxygen sensor. The synergistic effect among all components was realized and maximized, leading to a superior performance of oxygen sensing compared to any component alone. The most important was that the composite material showed a fast response towards oxygen with an excellent linear relationship.

Hierarchically structured layered-double-hydroxides derived by ZIF-67 for uranium recovery from simulated seawater.

Under the background of increasing and sustainable development of nuclear industry, it is significant to develop materials with high adsorption capacity and high selectivity of uranium as adsorbents. In this work, novel Mg-Co layered-double-hydroxide (LDH) with hierarchical structure was synthesized successfully via self-sacrifice template by ZIF-67. X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller surface area measurement (BET) and X-ray photoelectron spectroscopy (XPS) characterization were conducted, which confirmed the specifically hollow structured material possesses high surface area and abundant mesopores that makes uranium ions diffuse into it more easily. In typical batch adsorption experiments, varieties of parameters were investigated in details. In addition, adsorption of trace concentration of uranium (ppb level) in simulated seawater was also studied. The results showed as-prepared Mg-Co LDHs are promising adsorbents for extraction of uranium from simulated seawater.

Recovery of uranium(vi) from aqueous solutions using a modified honeycomb-like porous carbon material.

Researchers have focused their attention on environment-friendly adsorption materials to solve the energy shortage problem and guarantee the sustainable development of human society. For that matter, pomelo peel, which is a low-cost and universal biomass waste, can be used as an effective carbon source with a large specific surface area. In this paper, a novel composite adsorbent, consisting of a three-dimensional honeycomb-like porous carbon material and MnO2 nanowires (HLPC/MnO2), has been successfully synthesized using alkaline activation followed by a carbonization procedure at high temperatures and in situ growth of MnO2 nanowires. The as-prepared composite was characterized using XRD, FT-IR, XPS, SEM, TEM and BET. The surface area of the HLPC reached 1147.41 m2 g-1. The results of the adsorption experiments show that the highest adsorption value of the HLPC/MnO2 composite was 238.09 mg-U per g-adsorbent at pH 5. The thermodynamic and kinetic parameters demonstrate that the removal process correlates well with a Langmuir adsorption isotherm model and pseudo-second-order kinetic model. Thus, the HLPC/MnO2 composite is an excellent adsorbent for removing uranium(vi) ions from aqueous solutions.

A graphene oxide/amidoxime hydrogel for enhanced uranium capture.

The efficient development of selective materials for the recovery of uranium from nuclear waste and seawater is necessary for their potential application in nuclear fuel and the mitigation of nuclear pollution. In this work, a graphene oxide/amidoxime hydrogel (AGH) exhibits a promising adsorption performance for uranium from various aqueous solutions, including simulated seawater. We show high adsorption capacities (Qm = 398.4 mg g(-1)) and high % removals at ppm or ppb levels in aqueous solutions for uranium species. In the presence of high concentrations of competitive ions such as Mg(2+), Ca(2+), Ba(2+) and Sr(2+), AGH displays an enhanced selectivity for uranium. For low uranium concentrations in simulated seawater, AGH binds uranium efficiently and selectively. The results presented here reveal that the AGH is a potential adsorbent for remediating nuclear industrial effluent and adsorbing uranium from seawater.

Biosorption characteristics of Uranium (VI) from aqueous solution by pollen pini.

Uranium biosorption from aqueous solutions by pollen pini (Pinus massoniana pollen) was studied in a bath system. The biosorbent was characterized by Fourier-transform infrared spectroscopy and scanning electron microscope. The influences of pH, contact time and initial uranium concentration at room temperature were investigated and the experimental curves were obtained. The pollen pini exhibited the highest uranium sorption capacity at pH 5.0 after 2 h contact. At pH 2.5 pollen pini also exhibited a good uranium loading capacity (>15%). Therefore biosorption characteristics of uranium from aqueous solution onto pollen pini were examined at pH 2.5 as well. The kinetics followed a pseudo-second-order rate equation and adsorption process was well fitted with the Freundlich isotherm at both pH. The adsorption of uranium by the biosorbent was confirmed by energy dispersive spectroscopy. The present study suggested that pollen pini could be a suitable biosorbent for biosorption uranium (VI) from aqueous solution in a fast, low cost and convenient approach.

Coaxial CoMoO4 nanowire arrays with chemically integrated conductive coating for high-performance flexible all-solid-state asymmetric supercapacitors.

Flexible all-solid-state supercapacitors have offered promising applications as novel energy storage devices based on their merits, such as small size, low cost, light weight and high wearability for high-performance portable electronics. However, one major challenge to make flexible all-solid-state supercapacitors depends on the improvement of electrode materials with higher electrical conductivity properties and longer cycling stability. In this article, we put forward a simple strategy to in situ synthesize 1D CoMoO4 nanowires (NWs), using highly conductive CC and an electrically conductive PPy wrapping layer on CoMoO4 NW arrays for high performance electrode materials. The results show that the CoMoO4/PPy hybrid NW electrode exhibits a high areal specific capacitance of ca. 1.34 F cm(-2) at a current density of 2 mA cm(-2), which is remarkably better than the corresponding values for a pure CoMoO4 NW electrode of 0.7 F cm(-2). An excellent cycling performance of nanocomposites of up to 95.2% (ca. 1.12 F cm(-2)) is achieved after 2000 cycles compared to pristine CoMoO4 NWs. In addition, we fabricate flexible all-solid-state ASC which can be cycled reversibly in the voltage range of 0-1.7 V, and exhibits a maximum energy density of 104.7 W h kg(-1) (3.522 mW h cm(-3)), demonstrating great potential for practical applications in flexible energy storage electronics.

Characterization of a salt-tolerant bacterium Bacillus sp. from a membrane bioreactor for saline wastewater treatment.

High salt concentrations can cause plasmolysis and loss of activity of cells, but the salt-tolerant bacterium can endure the high salt concentrations in wastewater. In this research 7 salt-tolerant bacteria, which could survive in dry powder products and could degrade organic contaminants in saline wastewater, were isolated from a membrane bioreactor. The strain NY6 which showed the fastest growth rate, best property for organic matter degradation and could survive in dry powder more than 3 months was selected and characterized. It was classified as Bacillus aerius based on the analysis of the morphological and physiological properties as well as the 16S rRNA sequence and Neigh borjoining tree. The strain NY6 could survive in the salinity up to 6% and the optimal growth salinity is 2%; it belongs to a slightly halophilic bacterium. The capability of its dry powder products for COD removal was 800 mg COD/(g·day) in synthesized saline wastewater with salinity of 2%. According to salt-tolerant mechanism research, when the salinity was below 2%, the stain NY6 absorbed K(+) and Na(+) to maintain osmotic equilibrium, and when the salinity was above 2%, the NY6 kept its life by producing a large amount of spores.

Single-step synthesis of layered double hydroxides ultrathin nanosheets.

A novel single-step approach was developed to prepare large-scale MgAl-LDHs ultrathin nanosheets. The key point of the successful realization was that we employed a high concentration of H(2)O(2). Oxygen molecules, derived from in situ decomposition of H(2)O(2), were speculated to be the decisive factor leading to complete separation of LDHs layers. The ultrathin nanosheets were characterized by XRD, TEM, AFM, FT-IR, and TG-DSC. The results indicated that the thickness of these nanosheets was about 1.44 nm, which was almost in perfect agreement with the theoretical thickness of two LDHs layers. From the TG-DSC curves, the weight loss of these exfoliated MgAl-LDHs ultrathin nanosheets at 500°C was 18.5%, which was much smaller compared to the 32.3% weight loss of unexfoliated MgAl-LDHs.

Adsorption of Pb(II) and Cu(II) from aqueous solution on magnetic porous ferrospinel MnFe2O4.

The adsorption of Pb(II) and Cu(II) from aqueous solution on magnetic porous ferrospinel MnFe(2)O(4) prepared by a sol-gel process was investigated. Single batch experiment was employed to test pH effect, sorption kinetics, and isotherm. The interaction mechanism and the regeneration were also explored. The results showed that Pb(II) and Cu(II) removal was strongly pH-dependent with an optimum pH value of 6.0, and the equilibrium time was 3.0 h. The adsorption process could be described by a pseudo-second-order model, and the initial sorption rates were 526.3 and 2631.5 µmol g(-1)min(-1) for Pb(II) and Cu(II) ions, respectively. The equilibrium data were corresponded well with Langmuir isotherm, and the maximum adsorption capacities were 333.3 and 952.4 µmol g(-1) for Pb(II) and Cu(II) ions, respectively. The adsorbed Pb(II) and Cu(II) ions were in the form of the complex with oxygen in carboxyl and hydroxyl groups binding on the surface of magnetic porous MnFe(2)O(4). The sorbent could be reused for five times with high removal efficiency.

Magnetic, luminescent Eu-doped Mg-Al layered double hydroxide and its intercalation for ibuprofen.

A magnetic, luminescent Eu-doped Mg-Al layered double hydroxide with ibuprofen (IBU) intercalated in the gallery has been successfully prepared by a simple coprecipitation method. The physicochemical properties of the samples were well characterized by powder XRD, TEM, FTIR, TGA, inductively coupled plasma MS (ICP-MS), vibrating sample magnetometry (VSM), and fluorospectrophotometry. The results revealed that Fe(3)O(4) nanoparticles are coated on the surface of layered double hydroxides and the obtained (Mg(2)Al(0.95)Eu(0.05))(Fe)-(IBU) sample exhibits both superparamagnetic and luminescent properties, with a saturation magnetization value of 1.86 emu g(-1) and a strong emission band at 610 nm, respectively. Additionally, it was found that the ibuprofen loading amount is about 31 % (w/w), and the intercalated ibuprofen possesses sustained release behavior when the magnetic, luminescent composite is immersed in simulated body fluid (SBF).

Aggregation and supramolecular chirality of achiral amphiphilic metalloporphyrins.

Metalloporphyrin derivatives with three hydrophobic dodecyl chains and a hydrophilic ester or carboxylic acid substituent were designed in order to clarify the effect of the central metal ions on the aggregation as well as the supramolecular chirality in the Langmuir-Schaefer films. All the metalloporphyrins showed good spreading behavior on water surface and can be transferred onto solid substrates. The transferred films were characterized by a variety of methods including UV-visible spectroscopy, circular dichroism (CD) spectroscopy, FTIR spectroscopy, atomic force microscopy (AFM) and scanning electron microscope (SEM) measurements. It has been found that the copper derivative forms J-aggregates as well as H-aggregates in the film. Moreover, the film showed strong CD signals. Change from the ester substitution to carboxylic acid caused the decrease of the supramolecular chirality. On the contrary, the zinc derivative showed only a negligible CD signal although the corresponding free base could assemble into a chiral assembly. A possible mechanism for the subtle relationship between supramolecular chirality and molecular structures has been proposed.

Surface property and in vitro biodegradation of microspheres fabricated by poly(epsilon-caprolactone-b-ethylene oxide) diblock copolymers.

Microspheres fabricated by biodegradable polymers with tunable surface properties show great potentials as microcarriers in in vitro cell cultivation and tissue engineering. Herein we reported a new method to regulate the surface property and morphology of microspheres via the synthesis of biodegradable amphiphilic block copolymers with adjustable compositions. The poly(epsilon-caprolactone-b-ethylene oxide) diblock copolymers with functional amino end groups bonding to the PEO block (PCL-b-PEO-NH(2)) were synthesized by sequential ring-opening polymerization with potassium bis(trimethylsilyl) amide as initiator. The copolymers were characterized by gel permeation chromatography (GPC) and (1)H NMR, and then used to fabricate microspheres by w/o/w double emulsion solvent evaporation technique. The surface properties of microspheres were studied by means of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The results indicated that both the fabrication conditions and copolymer composition have great influences on the surface morphology and property of microspheres. The reactive amino functional groups are dominantly located on the surface of microspheres. The in vitro degradation of microspheres was studied by following the morphological changes of microspheres. The influences of hydrophilic PEO out-layers on the enzymatic degradation of microspheres were discussed. These microspheres with controllable surface morphology and amino functional groups are expected to be promising alternatives for the further biomimetic modification to promote cell growth on materials.

Photogeneration of free radicals (*OH and HB*-) and singlet oxygen (1O2) by hypocrellin B in TX-100 micelles microsurroundings.

To solve the problems faced in clinical use of hypocrellins, a water-soluble preparation of Hypocrellin B (HB), HB-Triton X-100 (TX-100) micelles, was prepared. To evaluate the photodynamic activity, the free radicals (*OH and HB*-) and singlet oxygen (1O2) generated via photosensitization of the preparation in aqueous solution were detected by using electron paramagnetic resonance (EPR) and spectrophotometric methods. It was observed that 1O2 was formed with a quantum yield of 0.72, similar to that for HB in organic solvents, further, hydroxyl radicals (*OH) could also be efficiently produced by the new preparation, which have never before been detected following HB photoactivities. In addition, the semiquinone anion radicals (HB*-) could also be generated via the self-electron transfer between an excited triplet state and a ground state molecule. The accumulation of HB*- would replace that of *OH or 1O2 with the depletion of oxygen in the system. All these findings suggested that the HB-TX-100 micelles could play the photodynamic action through not only the type I mechanism by free radicals (*OH, O2*- and HB*-) but also the type II mechanism by singlet oxygen (1O2). It can be concluded further that the new preparation basically maintains the inherent photodynamic activity of HB, or even higher.