Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 1Citation - Scopus: 1Phosphate Recovery From Digestate Using Magnesium-Modified Fungal Biochar(Springer, 2024) Bayrakdar, Alper; Madenli, Ozgecan; Bayrakdar, Alper; Deveci, Ece Ummu; Calli, Baris; 03.07. Department of Environmental Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyMg-rich biochars have been used for the removal and recovery of phosphate (PO43-) and ammonium (NH4+) from waste streams. In this study, a novel magnesium-modified biochar (Mg-FBC) was synthesized by immobilizing waste magnesite dust (WMD) into Aspergillus niger fungal biomass for the adsorption of PO(4)(3- )and NH4+. Pyrolysis at various temperatures and analysis using techniques such as SEM-EDS, TGA, XRD, FTIR, and BET revealed that biochar produced at 650 degrees C (Mg-FBC650) exhibited enhanced surface properties favorable for effective adsorption. This improvement is attributed to the increased surface area facilitated by the hyphal structure of A. Niger and the effective dispersion of MgO on its surface. In experiments using a synthetic phosphate solution, the adsorption capacity reached 595 mg PO43-/g BC, fitting the Langmuir model at pH 9. In addition, experiments with the liquid fraction of a real digestate (LFD) showed adsorption capacities of 502 mg PO43-/g BC and 150 mg NH4+/g BC, respectively. The adsorption mechanism was elucidated through SEM-EDS, XRD, and FTIR analyses confirming that Mg-FBC650 facilitates a multifaceted adsorption mechanism, including adsorption, electrostatic attraction, chemical precipitation, and surface complexation. Consequently, PO43- was the primary adsorbate in the synthetic solution, while both PO43- and NH4+ were effectively removed from the LFD, indicating that Mg-FBC650 has substantial potential as an efficient adsorbent for nutrient removal. As a result, Mg-FBC650 is believed to hold significant potential as a slow-release and readily transferable bio-fertilizer, particularly suitable for application in soils deficient in organic matter, nitrogen, and phosphorus. [GRAPHICS] .Article Citation - WoS: 2Citation - Scopus: 2The Compaction Behavior of Magnesium-Expanded Natural Graphite Powder Mixtures: Tensile Strengths of Compacted Pellets(Elsevier, 2024) Guden, Mustafa; Güden, Mustafa; Betin, Bahattin Berkan; Heptepe, Cafer Can; Gulec, Efe Bati; Yagci, Yavuz Emre; Figen, Aysel Kanturk; Filiz, Bilge Coskuner; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe effects of Expanded Natural Graphite (ENG) content, powder mixing method and compaction pressure on the tensile strengths of Magnesium AZ91 (9 wt% Al, 1 wt% Zn and 0.2 wt% Mn) + ENG powder mixture pellets were investigated. The tensile strengths of the pellets increased with an increase in the ENG content and compaction pressure and also with the applied powder ball milling. However, the compaction pressures above 500 MPa resulted in shear banding.Article Citation - WoS: 2Citation - Scopus: 2The Synthesis of Super-Hydrophilic and Hard Mgb2 Coatings as an Alternative To Electroless Nickel Coatings(Slovenska Akademia Vied, 2018) Bülbüll, Ferhat; Güney, M.; Jafarpour, Somaiyeh; 01. Izmir Institute of TechnologyIn this study, we report the electroless deposition using an alternative technique for the fabrication of hard and super-hydrophilic MgB2 films. MgB2 films on AZ91 magnesium alloys were prepared using an electroless bath containing magnesium diboride nanopowders, sodium hypophosphite, sodium succinate, sodium acetate, and dimethyl sulfoxide. The electroless deposition was carried out in a bath kept at a bath temperature of 95 degrees C for 60 min. After deposition, the coated samples were annealed at 300 degrees C for 60 min to investigate crystallization, morphology, and the changes in the hardness and wettability. The phase composition, morphology, the hardness, and the contact angle of produced coatings were studied by X-ray diffractometer, scanning electron microscopy, microhardness tester, and contact angle measurement system, respectively. The coatings exhibited a dense and nodular structure with strong grain connections. As-deposited and annealed MgB2 films showed an orientation with the (101) reflection, and the highest hardness value (500 HV0.01) was obtained from the annealed coating. Both synthesized coatings had a super-hydrophilic surface.Article Citation - WoS: 10Electrolysis of Mgcl2 With a Top Inserted Anode and an Mg-Pb Cathode(Springer Verlag, 1994) Güden, Mustafa; Güden, Mustafa; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyHigh energy consumption in the production of magnesium by molten salt electrolysis is mainly due to the recombination of magnesium and chlorine. The large interelectrode distance used, in conventional techniques, to reduce the extent of ‘back reaction’, results in a significant potential drop. A laboratory cell that enables the operation with smaller interelectrode distance and easy separation of electrode products has been used to study electrolytic magnesium production. The cell features a top inserted graphite anode and a Mg-Pb alloy cathode at the bottom. Current efficiency and power consumption were determined at 690° C using a current density of 0.48 A cm−2. Experiments were performed to study the effects of MgCl2 concentration and anode-cathode distance (a.c.d.) on cell operation. Results indicated that an electrolyte containing 20% MgCl2 (equiweight NaCl:KCl and 1 % NaF) with a 3 cm a.c.d. reduced the cell voltage to 3.72 V. This value corresponds to an energy consumption of 11.3 kWh kg−1 including the refining of Mg-Pb alloy produced at the cathode. This cell performance is more energy efficient compared to conventional magnesium cells.Article Citation - WoS: 19Citation - Scopus: 21Effect of Strain Rate on the Compressive Mechanical Behavior of a Continuous Alumina Fiber Reinforced Ze41a Magnesium Alloy Based Composite(Elsevier Ltd., 2006) Güden, Mustafa; Akil, Övünç; Güden, Mustafa; Çiftçioğlu, Muhsin; Hall, Ian W.; Taşdemirci, Alper; Çiftçioğlu, Muhsin; 03.02. Department of Chemical Engineering; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThe compressive mechanical response of an FP™ continuous fiber (35 vol.%) Mg composite has been determined in the transverse and longitudinal directions at quasi-static and high strain rates. It was found that the composite in the transverse direction exhibited strain rate sensitivity of the flow stress and maximum stress within the studied strain-rate range of 1.3 × 10−4 to 1550 s−1. The failure strain in this direction, however, decreased with increasing strain rate. Microscopic observations on the failed samples have shown that the composite failed by shear banding along the diagonal axis, 45° to the loading axis. Twinning was observed in the deformed cross-sections of the samples particularly in and near the shear band region. The strain rate sensitivity of the fracture stress of the composite in transverse direction is attributed to the matrix strain rate sensitivity. In the longitudinal direction, the composite failed by kink formation at quasi-static strain rates, while kinking and splitting were observed at the high strain rates. The maximum stress in the longitudinal direction was, however, found to be strain rate insensitive within the strain rate regime of 1.3 × 10−4 to 500 s−1. In this direction, similar to transverse direction, twinning was observed in the highly deformed kink region. Several different reasons are proposed for the strain rate insensitive compressive strength in this direction.