Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - Scopus: 3The Surface Charge of Unsupported Nano-Structured Titania Ceramic Membrane Top Layers With Varying Calcination Temperatures(University of Chemical Technology and Metallurgy journal@uctm.edu, 2019) Erdem, İlker; Çiftçiog̀lu, MuhsinTitania is one of the most preferable ceramic membrane materials of superior durability (as zirconia) when compared to that of other ceramics, e.g. alumina or silica. The surface charge of the membrane top layer is an important parameter of the separation performance of the multilayer ceramic membrane due to the Donnan exclusion mechanisms. In this study, the change of the surface charge of unsupported nano-structured titania top layer is investigated with calcination temperature variation. The effect observed indicates the possibility of preparation of tailor-made top layers for multilayer ceramic membranes. © 2019 Elsevier B.V., All rights reserved.Article Citation - WoS: 10Citation - Scopus: 11Production of Mn3O4 Nanoparticles From a Manganiferous Iron Ore via Reductive Leaching, Precipitation, and Calcination(Elsevier, 2022-02) Altiner, Mahmut; Top, Soner; Bouchekrit, Chafia; Kursunoglu, SaitThe synthesis of Mn3O4 nanoparticles from a manganiferous iron ore through reductive leaching, precipitation, and calcination was investigated. The reductive leaching results showed that Mn (99.9%) was almost completely extracted into the leaching solution along with a substantial amount of Mg (99.9%), Al (99.5%), Ca (80%), and Fe (22.9%) under the following conditions: 30 g/L tartaric acid as a reducing agent, 1 M HCl solution, leaching temperature of 90 ?, and leaching duration of 3 h. In the first precipitation step, Fe and Al were expelled from the pregnant leach solution by the addition of NaOH prior to conducting the precipitation experiments for the production of manganese carbonate (MnCO3) particles from the purified solution. In the second precipitation step, MnCO3 particles were produced using sodium carbonate (Na2CO3) as the precipitating agent. The effects of parameters such as reaction temperature, Na2CO3 concentration, and experimental duration were investigated using the Taguchi approach. Manganse(II) was precipitated in the form of MnCO3 particles (97.4%) under the following conditions: a temperature of 30 ?C, Na2CO3 concentration of 0.014 mol/L, and duration of 30 min. The precipitate was observed to have a structure similar to that of rhodochrosite (MnCO3). Thermogravimetric/ differential thermal analyses were subsequently performed in three different atmospheres (air, oxygen, and nitrogen) to select a suitable atmosphere for calcination. The experimental results indicated the formation of hausmannite (Mn3O4) with a purity of 97.5% Mn3O4, 0.42% MgO, 1.66% CaO, and 0.34% FeO. The specific surface area, particle size, Curie temperature, magnetisation, coercivity, and remanence ratio of the final product obtained via 3 h of calcination at 350 C were estimated to be 133.3 m(2)/g, < 142.2 nm, 56 K, 10.10 Am-2/kg, 0.35 T, and 0.19, respectively. The characterisation results revealed the excellent low-temperature ferromagnetic properties of the produced Mn3O4 nanoparticles.Article Citation - WoS: 6Citation - Scopus: 8Influence of Calcination Temperature on Microstructure and Surface Charge of Membrane Top Layers Composed of Zirconia Nanoparticles(Australian Ceramic Society, 2015) Erdem, I.; Ciftcioglu, M.; Ciftҫioğlu, M.The purpose of the research is to investigate the changes in microstructure and physicochemical characteristics, mainly surface charge (i.e. zeta potential) of zirconia membrane top layer during calcination. Zirconia is one of the most commonly preferred materials for ceramic membrane top layers due to its superior durability. The physicochemical properties of the top layer composed of submicron / nano particles is necessary not only for Donnan exclusion but also for dynamics of membrane fouling. In the present research the possibility of preparation of zirconia top layers with varying surface charge with changing calcination temperature was shown and a correlation between phase transformation and surface charge was determined.