PVDF/PU blend membrane separator for lithium-ion batteries via non-solvent-induced phase separation (NIPS)

Membrane separator based on the polyvinylidene fluoride (PVDF) is prepared via the non-solvent-induced phase separation (NIPS) method with water and ethanol as non-solvent and a mixture of dimethylformamide (DMF) and acetone as solvent. The effect of various acetone/DMF ratios and non-solvent material on the physical and electrochemical properties of the separator is studied by FE-SEM, tensile strength, electrochemical AC-impedance spectroscopy (EIS), thermal stability, and linear sweep voltammetry (LSV). The charge-discharge studies are carried out by fabricating a lithium foil/polymer electrolyte membrane/LiFePO4 cell. The results show that with the change of solvent and non-solvent, the structure and morphology of the separator change and its physical and electrochemical properties. The results indicate that the membrane sample with non-solvent ethanol, acetone/DMF: 80/20 (wt/wt), and PVDF/PU: 95/5 (wt/wt) shows high porosity (66.3%) and high ionic conductivity (1.34 mS/cm) as well as excellent thermal stability.

     

Naked magnetite nanoparticles for both clean-up and solid-phase extraction-trace determination of mercury

A new solid-phase extraction method was developed for trace determination of Hg(II) by using a small amount of naked magnetite nanoparticles as an adsorbent. The magnetite nanoparticles were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The adsorbed Hg(II)-dithizone complex was eluted with 1.0 mL aliquot of an acidic 1-propanol solution prior to electrothermal atomic absorption spectrometry. A huge positive effect was found on the mercury adsorption by ionic strength. Under optimized condition, a linear calibration curve was obtained for mercury in the range of 0.2–50 ng mL^?1 with relative standard deviation in the range of 0.5–2.0%. The limit of detection and enrichment factor were 0.01 ng mL^?1 and 98.3, respectively. The effects of coexisting ions were studied extensively, and a new clean-up procedure was used to remove the matrix effects by using a simple sample pretreatment step using a little amount of magnetite nanoparticles. The method was successfully applied to the determination of Hg(II) in different water and human urine samples and a commercial sodium nitrate.     

Polymerization of β‐cyclodextrin in the presence of bentonite clay to produce polymer nanocomposites for removal of heavy metals from drinking water

New hybrid organic–inorganic nanocomposites consist of β‐cyclodextrin (β‐CD)/epichlorohydrin (ECH), and bentonite clay were prepared by direct intercalation through one step emulsion polymerization. The structure and thermal stability of prepared nanocomposites were investigated by Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), field emission‐scanning electron microscopy (FE‐SEM), energy dispersive X‐ray analysis (EDAX), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), differential of differential scanning calorimetry (DDSC), thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analyses. The observed results show that the β‐CD polymer/clay nanocomposites (β‐CD–ECH polymer/clay) with higher thermal stability than β‐CD–ECH polymer were successfully prepared. The removal of heavy metals such as Cu(II), Zn(II) and Co(II) ions from drinking water was studied using a batch method at ambient temperature. The removal percentage and distribution coefficients (Kd) were determined for the adsorption system. It was found that the β‐CD–ECH polymer/clay nanocomposites showed higher removal capacity for Co²⁺, Cu²⁺ and Zn²⁺ ions in comparison with β‐CD–ECH polymer. The selectivity order could be given as Zn²⁺ > Cu²⁺ > Co²⁺. Copyright © 2016 John Wiley & Sons, Ltd.     

A study on the two binding sites of hexokinase on brain mitochondria

Background  

Type I hexokinase (HK-I) constitutes the predominant form of the enzyme in the brain, a major portion of which is associated with the outer mitochondrial membrane involving two sets of binding sites. In addition to the glucose-6-phosphate (G6P)-sensitive site (Type A), the enzyme is bound on a second set of sites (Type B) which are, while insensitive to G6P, totally releasable by use of high concentrations of chaotropic salts such as KSCN. Results obtained on release of HK-I from these "sites" suggested the possibility for the existence of distinct populations of the bound enzyme, differing in susceptibility to release by G6P.     

Diastereoselective Synthesis of Novel Pyrrolidine or Pyrrolizine‐Fused Benzo‐δ‐sultams via 1,3‐Dipolar Cycloadditions

The synthesis of novel pyrrolidine or pyrrolizine‐fused benzosultams is described. A number of (E)‐N‐(2‐formylphenyl)‐N‐alkyl‐2‐phenylethenesulfonamides derivatives were synthesized and subjected to intramolecular [3 + 2] cycloaddition with azomethine ylides derived in situ from the reaction with sarcosine, phenylglycine, and L‐proline.     

Sonochemically synthesis of pyrazolones using reusable catalyst CuI nanoparticles that was prepared by sonication

A simple and green process to prepare copper iodide in nano scale via sonication was carried out. Subsequently, this nanoparticles was used as an efficient catalyst for the synthesis of 2-aryl-5-methyl-2,3-dihydro-1H-3-pyrazolones via four-component reaction of hydrazine, ethyl acetoacetate, aldehyde and β-naphthol in water under ultrasound irradiation. The combinatorial synthesis was attained for this procedure with applying ultrasound irradiation while making use of water as green ambient. Simple work-up, excellent yield of products and short reaction times are some of the important features of this protocol. Notably, this catalyst could be recycled and reused for five times without noticeably decreasing the catalytic activity.     

Electromembrane extraction of levamisole from human biological fluids

Electromembrane extraction coupled with high-performance liquid chromatography (HPLC) and ultraviolet (UV) detection was developed for the determination of levamisole in some human biological fluids. Levamisole migrated from 4 mL of different acidized biological matrices, through a thin layer of 2-nitrophenyl octyl ether containing 5% tris-(2-ethylhexyl) phosphate immobilized in the pores of a porous hollow fiber, into a 20-μL acidic aqueous acceptor solution present inside the lumen of the fiber. The parameters influencing electromigration were investigated and optimized. Within 15 min of operation at 200 V, levamisole was extracted from different biological fluid samples with recoveries in the range of 59-65%, which corresponded to preconcentration factors in the range of 118-130. The calibration curves showed linearity in the range of 0.5-10, 0.2-10 and 0.1-10 μg/mL for plasma, urine and saliva, respectively. Limits of detection of 0.1, 0.07 and 0.05 μg/mL and limits of quantification of 0.5, 0.2 and 0.1 μg/mL were obtained for plasma, urine and saliva, respectively. The relative standard deviations of the analysis were found to be in the range of 5.6-9.7% (n = 3). Electromembrane extraction was successfully processed for determination of levamisole in plasma, urine and saliva samples.     

Nonelectrolyte NRTL-NRF model to study thermodynamics of strong and weak electrolyte solutions

An electrolyte activity coefficient model is proposed by combining non-electrolyte NRTL-NRF local composition model and Pitzer–Debye–Hückel equation as short-range and long-range contributions, respectively. With two adjustable parameters per each electrolyte, the present model is applied to correlation of the mean activity coefficients of more than 150 strong aqueous electrolyte solutions at 298.15 K. Also the results of the present model are compared with the other local composition models such as electrolyte-NRTL, electrolyte-NRTL-NRF and electrolyte-Wilson-NRF models. Moreover, the present model is used for prediction of the osmotic coefficient of several aqueous binary electrolytes systems at 298.15 K. Also the present activity coefficient model is adopted for representation of nonideality of the acid gases, as weak gas electrolytes, soluble in alkanolamine solutions. The model is applied for calculation of solubility and heat of absorption (enthalpy of solution) of acid gas in the two {(H₂O + MDEA + CO₂) and (H₂O + MDEA + H₂S)} systems at different conditions. The results demonstrate that the present model can be successfully applied to study thermodynamic properties of both strong and weak electrolyte solutions.     

Synthesis, characterization and crystal structures of di-three-coordinated copper(I) macrocyclic Schiff base complexes

The air-stable di-copper(I) complexes Cu₂L(SCN)₂ (1) and Cu₂L(SCN)_1.86I_0.14 (2) of the N₄ macrocyclic Schiff base ligand L have been synthesized and characterized by IR, elemental analysis, UV-Vis and crystal structure determination. X-ray analysis of the complexes shows an approximate distorted trigonal planar geometry around each copper(I) ion that is constructed from one N-bonded thiocyanate (or iodide in 2) group and two imine nitrogen atoms. DFT calculations were used to determine the structural features of the Cu₂L(SCN)₂ complex, and these were consistent with the experimental data for the complex.     

Nanomolar Determination of Penicillamine by Using a Novel Cobalt/Polyaniline/Carbon Paste Nanocomposite Electrode

The fabrication of cobalt/polyaniline nanocomposite was performed using a simple chemical method. It was characterized by using TEM and FTIR techniques. The nanocomposite was applied as a modifier in a carbon paste electrode for selective determination of penicillamine. Penicillamine reacts with emeraldine polyaniline by using 1,4, Michael addition reaction. It can decrease the voltammetric peak current of emeraldine polyaniline. The effects of pH and potential sweep rate on the response of the electrode were investigated. Differential pulse voltammetry was applied for quantitative determination. Dynamic linear ranges were obtained in the ranges of 1.0×10^?8–1.0×10^?7 mol L^?1 and 1.0×10^?9–1.0×10^?8 mol L^?1.