Papers by Keyword: Cobalt

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Authors: Anton Gnidenko
Abstract: Quantum-mechanical calculations were performed for investigation of tensile strength for WC/Co/WC systems with the thickness of the cobalt interlayer of 3 and 7 atomic layers. It has been shown that the cobalt interlayer increasing leads to decreasing of the tensile strength from 17 GPa to 14 GPa. In addition, vacancy-type defect formation reduces the tensile strength of about 2 times.
Authors: Jia Hai Ye, Ling Jun Duan, Lian Lian Jin
Abstract: Abstract. The novel tetraphenylethylene (TPE) based sensor 1 bearing bis(2-pyridin-2-ylmethyl) amine (BPA) unit and BODIPY unit linked with triazole moieties could be obtained by click reaction efficiently. It was employed as a fluorescence probe for the selective recognition of Cu2+ and Co2+. They form stable 1:1 stoichiometric complexes and the lowest limit of detection was 1×10-7 M.
Authors: A. El Bouari, A. El Jazouli, J.M. Dance, G. Le Flem, R. Olazcuaga
Authors: I.I. Parfenova, E.I. Yuryeva, Sergey A. Reshanov, V.P. Rastegaev, A.L. Ivanovskii
Authors: So Young Kang, Jong Un Lee, Kyoung Woong Kim
Abstract: Pseudomonas aeruginosa biomass was used to investigate the biosorption properties of heavy metals in wastewater. The biosorption isotherm of Co2+ was best described by the Langmuir model when washed cells were employed, and results obtained utilizing heat-treated P. aeruginosa were also adequately represented by a Langmuir sorption isotherm. In contrast, the sorption isotherm involving unwashed P. aeruginosa showed a different isotherm profile and did not attain equilibrium in the range of metal concentrations investigated; the amount of Co2+ uptake increased with increasing initial metal concentration but never reached adsorption equilibrium, most likely due to bacterial production of extracellular polymeric substances (EPS). The biosorption results utilizing unwashed P. aeruginosa were best described by a Freundlich isotherm. The level of metal adsorption in low pH was significantly small due to competition between the cation and H+ ions for binding sites distributed on cell surfaces, while the increase in pH favored metal sorption because of the elevated quantities of negatively charged surface functional groups. The sorption of Co2+ was strongly influenced by the presence of competing cations in the solution. Trivalent Cr3+ added to the solution was preferentially adsorbed onto the cells relative to Co2+ and Ni2+. The results may be attributed to the higher adsorption affinity of Cr3+ in comparison to either Co2+ or Ni2+. The affinity order (Cr3+ > Co2+ » Ni2+) was maintained over a pH range up to 5.3 in a mixture solution.
Authors: Xin Ge Zhang, Cyrille Decès-Petit, Sing Yick, Mark Robertson, Wei Qu, Yong Song Xie, Rob Hui, Edward Styles, Justin Roller, Olivera Kesler, Radenka Maric, Dave Ghosh
Abstract: In this study, an addition of Co and Cu oxides to Sm0.2Ce0.8O1.9 (SDC) was studied to improve the SDC sinterability. It has been found that both Co and Cu oxide are very effective as sintering aids, and the SDC sintering temperature can be reduced from 1400°C without aids to below 1000°C with only 1at.% of either Cu or Co. As compared to the pure SDC, a slight decrease of ionic conductivity was observed in SDC with Cu sintering aid. There is no obvious effect on electrochemical property of SDC with Co sintering aid under 2.5at.%.
Authors: A. Lukawska, Z. Jagoo, Gregory Kozlowski, Z. Turgut, H. Kosai, A. Sheets, T. Bixel, A. Wheatley, P. Abdulkin, B. Knappett, T. Houlding, V. Degirmenci
Abstract: AC magnetic heating of superparamagnetic Co and Fe nanoparticles for application in hyperthermia was measured to find a size of nanoparticles that would result in an optimal heating for given amplitude and frequency of ac externally applied magnetic field. To measure it, a custom-made power supply connected to a 20-turn insulated copper coil in the shape of a spiral solenoid cooled with water was used. A fiber-optic temperature sensor has been used to measure the temperature with an accuracy of 0.0001 K. The magnetic field with magnitude of 20.6 μT and a frequency of oscillation equal to 348 kHz was generated inside the coil to heat magnetic nanoparticles. The maximum specific power loss or the highest heating rate for Co magnetic nanoparticles was achieved for nanoparticles of 8.2 nm in diameter. The maximum heating rate for coated Fe was found for nanoparticles with diameter of 18.61 nm.
Authors: Farah Aimi Fuadi, Siti Nor Izuera Nor-Azemi, Syed Shatir A. Syed-Hassan
Abstract: Four types of biomass were characterized to investigate its metal adsorption capacity. The biomass were soaked in with nickel and cobalt solutions to examine the effect of biomass to amount of metal adsorbed. Oil palm mesocarp fibre (OPMF), empty fruit bunch (EFB), palm kernel shell (PKS) and sawdust were used in this study. Among all the biomass studied, oil palm mesocarp fibre shows the highest adsorption capacity with 1.8 mg/g and 1.6 mg/g of nickel and cobalt uptake, respectively. The metals adsorbed on the biomass were found to disperse into nanosize range.
Authors: Yan Xing
Abstract: This fundamental work deals with the biosorption removal of Co(II) using a Mycobacterium phlei strain. Several variables that have an effect on the capacity of cobalt biosorption from aqueous solution by Mycobacterium phlei were studied. particularly the effects of solution pH, initial Co(II) concentration, contact time and biomass dose. The experimental data were modeled by Langmuir and Freundlich isotherm models. Langmuir model resulted in the best fit of the adsorption data. The maximum adsorption capacity for Co(II) was 68.22 mg/g. The best correlation was provided by the second-order kinetic model, implying that chemical sorption was the rate-limiting step. The practical implication of this study is the development of an effective and economic technology for Co(II) removal from wastewaters.
Authors: Kang Yan, Xue Yi Guo, Qing Hua Tian, Dong Li
Abstract: Substance flow analysis (SFA) of cobalt in China was carried out to analyze cobalt flows and stocks by using static SFA. Cobalt can be widely used in industry due to its high-melting point, high-strength, and well magnetism. In this static model, the relationship among inflows, outflows and stocks throughout the whole cobalt life-cycle in China were identified. According to the static model, the amount was calculated in the form of cobalt metal, in 2012, 29784t of cobalt was produced, and 30700t of cobalt was imported, 9400t exported and domestic consumption was 31700t, 9000t stocks of cobalt was consumed and 3000t old scrap was recycled in China. The ore index and recovery scrap resource of cobalt industry were 0.318 t/t and 0.136 t/t respectively.
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