2,859 publications from this institution
In this study simple, facile and highly active silver coated ZnO-chitosan (Ag/ZnO-CH) textile cotton supported nanocomposites were developed. The nanocomposites were characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-rays spectroscopy (EDX), fourier transform infrared spectroscopy (FTIR) and X-rays diffraction (XRD). The prepared nanocomposite fibers were used for the selective removal of seven model pollutants, including para-nitrophenol (p-NP), meta-nitrophenol (m-NP), ortho-nitrophenol (o-NP), 2,4,6-trinitrophenol (TNP), and dyes of methyl orange (MO), congo red (CR), and methyl red (MR). The apparent rate constant (K app ) of pseudo first order kinetic for p-NP was 2.813 × 10 −3 s −1 and 1.663 × 10 −3 s −1 for MO dye. Among the different nitroarenes, the reaction rate matched the ordered of p-NP >TNP > m-NP > o-NP, while for the dyes it was MO > CR > MR. Ag/ZnO-CH nanocomposites were recycled multiple times without any significant loss of its catalytic activity. The higher stability of the Ag/ZnO-CH nanofibers also allows the catalyst to be separated easily by just pulling the catalyst from the reaction mixture and reused. The clean and facile, simple synthesis procedure, outstanding properties and low-cost supports allow these catalysts to be used in the reduction of the organic pollutants individually as well as collectively in the mixture of dyes in wastewater at room temperature.
The oxidation of Rizatriptan by diperiodatoargentate(III) has been studied by spectrophotometry at neutral pH. The kinetics of the reaction of Rizatriptan has been shown to principle of non-complementary oxidation steps. The initial step involves the deprotonated of the diperiodatoargentate(III) with the alkali; this rearranges during the displacement of a ligand to give free periodate and takes up another ligand monoperiodateargentate(III), combines with a substrate to endow with an intermediate complex which decomposes within a slow step to provide the final product in the following step with a first-order rate constant. The main product was identified by spot test, Fourier- transform infrared spectroscopy, Nuclear magnetic resonance and Liquid chromatography-mass spectrometry spectrum. A conceivable mechanism including pre equilibrium of adducts development between the complex and reductant was planned from the kinetics study. The rate conditions got from system can clarify all exploratory phenomena, and the activation parameters alongside rate constants of the rate determining step were ascertained.
The casting and preparation of ultrafiltration ZnO modified cellulose acetate membrane (CA/ZnO) were investigated in this work. CA membranes were fabricated by phase inversion using dimethylformamide (DMF) as a solvent and ZnO as nanostructures materials. Ultrafiltration (UF) performance, mechanical stability, morphology, contact angle, and porosity were evaluated on both CA- and ZnO-modified CA samples. Scanning electron microscopy (SEM) was used to determine the morphology of the membranes, showing different pore sizes either on rough surfaces and cross-sections of the samples, an asymmetric structure and ultra-scale pores with an average pore radius 0.0261 to 0.045 µm. Contact angle measurements showed the highest hydrophobicity values for the samples with no ZnO addition, ranging between 48° and 82.7° on their airside. The permeability values decreased with the increasing CA concentration in the casting solution, as expected; however, ZnO-modified membranes produced lower flux than the pure CA ones. Nevertheless, ZnO modified CA membranes have higher surface pore size, pore density and porosity, and improved surface hydrophilicity compared with pure CA membranes. The results indicated that the incorporated nano-ZnO tends to limit the packing of the polymer chains onto the membrane structure while showing antifouling properties leading to better hydrophilicity and permeation with consistent UF applications.
Abstract Bile salts are steroidal surfactants consisting of 2 to 12 monomers to form a micelle. The most important physiological property of bile salts is the solubilization of cholesterol. The bile salts make mixed micelle with phospholipids that enhance the bile salts ability to solubilize cholesterol. The mixed micelle formation in aqueous solution between two bile salts (sodium taurocholate [NaTC] and sodium deoxycholate [NaDC]) mixtures has been studied by tensiometric and fluorometric studies. The nonideal mixing behavior was examined for mixed systems, and synergism was found for the current mixed systems. Rubingh and Rosen models were used to analyze the bile salt‐bile salt binary mixtures, and the interaction parameters, as well as mixed micelle compositions at bulk and interface, have been computed as well as discussed one by one. The values of were achieved to be negative for all studied systems. In the solution mixtures, as the content of NaTC increases, the formation of micelles becomes slightly less favorable.
Developing non-noble-metal hydrogen evolution reaction electrocatalysts with high activity is critical for future renewable energy systems. The direct growth of active phases on current collectors not only eliminates using polymer binder but also offers time-saving preparation of electrode. In this Letter, we develop self-supported FeP nanorod arrays on carbon cloth (FeP NAs/CC) via low-temperature phosphidation of its Fe2O3 NAs/CC. As a novel 3D hydrogen evolution cathode in acidic media, the FeP NAs/CC exhibits high catalytic activity and only needs an overpotential of 58 mV to afford current density of 10 mA/cm2. This electrode also works efficiently in both neutral and alkaline solutions.
Hydrogels with different weight percent of [Formula: see text]-hydroxylethyl acrylamide and [Formula: see text]-(2-mannosylethyl) acrylamide were prepared, using [Formula: see text], [Formula: see text]-methylenebis (acrylamide) (MBA) (1.0[Formula: see text]wt.%) and ammonium persulfate (APS) (1.0[Formula: see text]wt.%) as the crosslinker and initiator, respectively. The successful preparation of hydrogels was confirmed by both inverted vial test and rheological measurements. These hydrogels were grinded into nanogel powders and applied as a bromelain stabilizer against high temperature by measuring the proteolytic activities of bromelain, which increased from 47% to [Formula: see text]95% under nanogel protection. This indicated that nanogels can be potentially applied as an enzyme stabilizer in food industry.
