Assessment of Agricultural Residue to Produce Activated Carbon-Supported Nickel Catalysts and Hydrogen Rich Gas.

The aim of this study was to synthesize chemically activated carbons from different agricultural residues, i.e., pistachio shell (PS), bitter orange peel (OP), and saffron petal (SP), and subsequently to use them as supports for loading a Ni catalyst. Supercritical water gasification of bio-oil was applied to investigate the catalytic performance of the resulting catalysts. The physicochemical properties of the activated carbon (ACs) and the catalysts (Ni/ACs) were characterized with BET, XRD, XPS, TEM, and TPD. The adsorption results showed that the ACs developed considerable pore structures, containing both micro- and mesopores, which was validated by the well-distributed active phases on the supports in the TEM images. Furthermore, it was found that the BET of AC(PS) was 1410 m2/g, which was higher than that of AC(OP) (1085 m2/g) and AC(SP) (900 m2/g). The results obtained from XRD mainly indicated the presence of the nickel phosphides phases, which was confirmed with the XPS and TPD analyses. The catalytic tests showed that by raising the process temperature, the total amount of gas and hydrogen increased. Furthermore, Ni/AC(PS) showed a superior catalytic activity. The highest total gas amount (i.e., 7.87 mmol/g bio-oil), together with 37.2 vol.% H2, was achieved using Ni/AC(PS) with a 1:10:100 catalyst:bio-oil weight ratio and a mass ratio of 1:10 (bio-oil/water) at T = 550 °C.Partial funding for open access charge: Universidad de Málag

Microwave-assisted synthesis of graphene modified CuO nanoparticles for voltammetric enzyme-free sensing of glucose at biological pH values

The effect of graphene nanosheets on the glucose sensing performance of CuO powders was investigated. CuO and graphene-modified CuO nanoparticles (NPs) were fabricated by microwave-assisted synthesis and characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The material was placed on a glassy carbon electrode (GCE) which then was characterized by cyclic voltammetry and chronoamperometry with respect to the capability of sensing glucose both at pH 13 and pH 7.4. The results revealed that the modified GCE has a fast and selective linear response to glucose at pH 13 that covers the 0.21 μM to 12 mM concentration range, with a 0.21 μM low detection limit. The presence of graphene nanosheets results in an improved sensitivity which is to 700 μA mM−1 cm−2. In solution of pH 7.4, the respective data are a linear analytical range from 5 to 14 mM; a 5 μM LOD and a sensitivity of 37.63 μA mM−1 cm−2 at working potential of −0.05 V (vs. Ag/AgCl) and scan rate of 50 mV s−1. Ascorbic acid, dopamine, uric acid, sucrose, maltose and fructose do not interfere. [Figure not available: see fulltext.]. © 2017, Springer-Verlag GmbH Austria, part of Springer Nature.1

In vitro electrochemical corrosion and cell viability studies on nickel-free stainless steel orthopedic implants.

The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen's structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments

Open circuit potential (<i>ocp</i>) vs. immersion time for the sample B.

<p>Open circuit potential (<i>ocp</i>) vs. immersion time for the sample B.</p

Cell viability on the TCP and stainless steels after one day, determined by fluorescence in the cytoplasmic extract.

<p>Cell viability on the TCP and stainless steels after one day, determined by fluorescence in the cytoplasmic extract.</p

Bode impedance (a), Bode phase angle (b) and Nyquist (c) plots; and equivalent electrical circuit used for the quantitative analyses of the impedance spectra (d).

<p>Bode impedance (a), Bode phase angle (b) and Nyquist (c) plots; and equivalent electrical circuit used for the quantitative analyses of the impedance spectra (d).</p

SEM micrograph of cells fixed on A (a), B (b), C (c), and 316L (d).

<p>SEM micrograph of cells fixed on A (a), B (b), C (c), and 316L (d).</p

Some properties of the stainless steel samples.

<p>Some properties of the stainless steel samples.</p

Equivalent electrical circuit parameters obtained by the EIS studies.

<p>Equivalent electrical circuit parameters obtained by the EIS studies.</p