Papers by Keyword: Manganese

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Authors: I.I. Parfenova, E.I. Yuryeva, Sergey A. Reshanov, V.P. Rastegaev, A.L. Ivanovskii
Authors: Chun Hua Liu, Chang Bin Xia
Abstract: The adsorption of Mn2+ ion on natural bentonite heated-treated at 110 °C or 200 °C and on acid-treated with H2SO4 from aqueous solutions has been investigated under different conditions,such as intial solution pH and initial Mn2+ion concentration.The results show that modified bentonite has a better adsorption capability,and the pH value is the main factor affecting adsorption;bentonite modified at higher temperature has the largest adsorption capability.The adsorption process in solution exhibits Langmuir behaviour and ion exchange and surface complex are chief adsorption form.
Authors: Jian Hua Wang, Zi Shi Wu, Xu Ping Su, Chang Jun Wu, Ya Liu, Hao Tu
Abstract: The influence of manganese in Zn-Mn and Zn-0.2wt.%Al-Mn bath on the morphology and growth kinetics of the galvanizing coatings has been studied using scanning electron microscopy equipped with energy dispersive spectroscopy. When galvanized in zinc bath, the coating consists mainly h and ζphase. When manganese is added in zinc bath, the morphology of ζ phase changes from fragmental to compact. Manganese favors the formation of the δ phase and inhibits the growth of the ζ phase.When galvanized in Zn-0.2wt.%Al bath, the coating consists only δ and h phase. With the addition of manganese in Zn-0.2wt.%Al bath, the morphology of δ phase changes from fragmental to compact The thickness of the Fe-Zn intermetallic phase layer in coatings decreases obviously when manganese is added into zinc and Zn-0.2wt.%Al bath, and the thickness increases slowly with the increase of immersion time.
Authors: Purnama Ningsih, Clovia Z. Holdsworth, Scott W. Donne
Abstract: Polypyrrole (PPy) and manganese (Mn) due their remarkable properties offers a good performance for electrochemical capacitors. Manganese modified polypyrole (Mn-modified PPy) thin films were chronoamperometically (CA) deposited on the platinum-titanium crystal resonator as a part of the electrochemical quartz crystal microbalance (EQCM). The performances of the thin films were then examined for performance using cyclic voltammetry (CV). The effects of pyrrole monomer and manganese oxides concentrations were also investigated in this study.
Authors: R. Maria Pérez, A. Abalos, José Manuel Gómez, Domingo Cantero
Abstract: The study describes the sorption of Cr, Cu, Mn and Zn by Pseudomonas aeruginosa AT18 isolated from a site contaminated with petroleum and heavy metals. The concentrations studied (mgL-1) were Cr-50, Cu-49, Mn-60 and Zn-70. The solution pH and ionic strength were very important factors in the metal biosorption performance and the biosorption capacity of Pseudomonas aeruginosa AT18 for Cr3+ Cu2+, Mn2+ and Zn2+. In aqueous solution the biosorption increased with increasing pH in the range 5.46-7.72. The results obtained in the experimental assays show that Pseudomonas aeruginosa AT18 has the capacity for biosorption of the metallic ions Cr3+, Cu2+ and Zn2+ in solutions, although its capacity for the sorption of manganese is low (22.39 mg Mn2+/g of biomass) in comparison to the Cr3+, Cu2+ and Zn2+ ions, as shown by the individual analyses. However, 20% of the manganese was removed from an initial concentration of 49.0 mgL- 1, with a Qm value similar to that obtained in solutions containing mixtures of Cr3+ Cu2+, Mn2+ and Zn2+. The chromium level sorbed by Pseudomonas aeruginosa AT18 biomass was higher than that for Cu, Mn and Zn, with 100% removal in the pH range 7.00-7.72 and a Qm of 121.90-200.00 mg of Cr3+/g of biomass. The remove of Cr, Cu and Zn are a result also of precipitation processes.
Authors: Marek Szkodo
Abstract: The laser surface alloying of 18/8 stainless steel with Mn, was carried out by 6 kW cw CO2 laser. The microstructure, chemical composition and phase identification of the modified layer were examined using scanning electron microscopy, energy dispersive X-ray spectroscopy and Xray diffractometry, respectively. Cavitation behavior of produced layers was investigated in a rotating disc facility. Cavitation properties of laser-processed steel were calculated in the initial stage of erosion, on the surface of about 4 mm2, on which cavitation intensity was constant. As a property characterizing the cavitation erosion resistance of materials was proposed for the depth of strain hardening. It was found that presence of manganese in the amount of 7.31% causes the highest increase hardness after alloying and the lowest depth of strain hardening due to cavitation loading.
Authors: Kozo Shinoda, Takamichi Yamamoto, Shigeru Suzuki, Tomoya Uruga, Hajime Tanida, Hidenori Toyokawa, Yasuko Terada, Yasufumi Takagaki
Abstract: Alloying elements are added to steel for improving surface properties such as corrosion resistance. The alloying elements exhibit different chemical characters, and they are often enriched to the surface of the alloys during annealing at high temperatures. In this study, depth-resolved X-ray absorption spectroscopy (XAS) measurements were carried out using a two-dimensional detector with geometrical arrangement of grazing exit in detection of fluorescence X-ray emitted from sample surface, in order to characterize the enrichment and oxidation of manganese on the surface layers of an Fe-Mn alloy annealed under low oxygen partial pressure. This technique facilitates non-destructive measurement for characterizing the compositional distribution of manganese in the depth direction. The results showed that manganese was enriched to surface layers of the Fe-Mn alloys during annealing at high temperatures and formed as manganese oxide. The preferential oxidation of manganese by annealing under low oxygen partial pressure is considered the driving force for their enrichment on the alloy surface.
Authors: N. Srisittipokakun, C. Kedkaew, Jakrapong Kaewkhao, Pichet Limsuwan
Abstract: The UV-visible spectra of soda-lime-silicate glass system with the base composition (65-x) SiO2: 10CaO: 25Na2O: xMnO2 % mol, (where x is 0.0, 0.02, 0.05, 0.10, 0.30 and 0.50 %mol) were studied at room temperature. The results are shown that the colors of glass samples were altered from colorless to dark purple with increasing of MnO2 concentration and were stable at room temperature. The color of glass sample with 0.3 %mol MnO2 was purple. Moreover, it has been found that the density and refractive index were contiguous. The optical absorption spectra can be confirmed the color of these glass samples. They exhibited a predominant broadband around 500 nm and it was clearly observed, its increasing since 0.1 %mol of MnO2. This band corresponds to an allowed transition from 5Eg5T2g, which attributed to Mn3+. When increasing MnO2 concentration, the absorption band due to Mn3+ ion was dominating.
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