Sürdürülebilir Kalkınma Amaçları
Yayınlar
- Kitap BölümüYalnız künye2021Challenges, novel applications, and future prospects of chalcogenides and chalcogenide-based nanomaterials for photocatalysis
Ates, Mehmet; Tanaydın, Mehmet Kayra; Yılmaz, Ersen
Nanomaterials are composed of several atoms or molecules, which may be of various sizes and morphologies. Manmade nanomaterials are specially produced to take advantage of the unique properties of nanoscale. There are many metal chalcogenides with different structures and compositions such as CdSe, InAs, CdS, GaN, InGeAs, CdTe, PbS, PbSe, ZnS, Na2S, CaTe, Ti2S, and Cu2Se. The diversity of metal chalcogenides is related to the orbit of transition metals. In this chapter, new studies using chalcogenide compounds as photocatalysts were explained under the subtopics of metal chalcogenides and their properties, semiconductive nanostructures, nanomaterial production technique, chemical synthesis methods, and metal chalcogenides as photocatalysts. Novel applications of metal chalcogenide-based materials like water splitters, organic pollutant degraders, self-cleaning agents chalcogenide glasses and thermoelectric materials are explained in detail under the relevant headings. Future prospects of chalcogenides are also evaluated from a different perspective.
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İncele - MakaleYalnız künye2021Scopus SJRQ2Determination of Optimum Process Conditions by Central Composite Design Method and Examination of Leaching Kinetics of Smithsonite Ore Using Nitric Acid Solution
Tanaydın, Mehmet Kayra; Bakıcı Tanaydın, Zümra; Demirkıran, Nizamettin
The leaching behavior of Tunceli smithsonite ore in nitric acid was evaluated in two study steps including optimization of leaching process and kinetics modeling. The individual and synergistic effects of effective parameters such as nitric acid concentration, solid-to-liquid ratio, stirring speed, and temperature on the dissolution rate of zinc were investigated using central composite design. Four factors including temperature (30–50 °C), nitric acid concentration (0.2–0.5 mol/L), stirring speed (350–600 rpm), and solid-to-liquid ratio (0.004–0.01 g/L) were investigated. The dissolution percent of zinc (97%) was obtained in 120 min of leaching time: acid concentration 0.5 mol/L, temperature 50 °C, stirring speed 500 rpm, and solid–liquid ratio 2/500 g/mL at the optimum conditions obtained using the central composite design. The dissolution kinetics of smithsonite was examined according to heterogenous models and it was found that the dissolution rate was controlled by ash layer diffusion process. It was found that the leaching rate increased with increasing temperature, stirring speed, and acid concentration as well as decrescent particle size and solid/liquid ratio. The trial data were analyzed by statistical and graphical methods and the activation energy of this leaching process was determined to be 28.63 kJ·mol−1. Graphical Abstract: [Figure not available: see fulltext.].
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İncele - MakaleYalnız künye2021Scopus SJRQ2Recovery of Cu(II) by Acorga M5640 After Leaching of Malachite Ore in Perchloric Acid Solutions
Demirkıran, Nizamettin; Tanaydın, Mehmet Kayra
Abstract: In the present study, the recovery of Cu2+ from the resulting actual leach solution after the leaching of malachite ore in perchloric acid solutions was examined by applying the solvent extraction method. The organic phase was prepared using Acorga M5640 and kerosene. The effects of the initial pH of solution, extractant concentration, Cu2+ concentration, temperature, and stirring speed on the extraction process were investigated. It was determined that the extraction yield increased with an increase in the extractant concentration, initial pH of aqueous solution, stirring speed, and temperature, and with a decrease in the concentration of Cu2+. To prevent or minimize Zn2+ transfer to the organic phase and to ensure maximum Cu2+ extraction from the aqueous phase, the optimal values for the initial pH of the aqueous phase, initial concentration of Cu2+, extractant concentration, temperature, and stirring speed were selected to be 1, 0.152 g/L, 4% (v/v), 25 °C, and 400 rpm, respectively. The stoichiometry and mechanism of the extraction process were determined applying the equilibrium slope method. The changes in the Gibbs free energy, enthalpy, and entropy were determined. The changes in these thermodynamic parameters were calculated to be − 3.87 kJ/mol, 64.67 kJ/mol, and 0.23 kJ/(mol K), respectively. Graphical Abstract: The extraction percentage of Cu2+ increases substantially when the initial pH of the leach solution increases from 0.1 to 1. The further increase in the initial pH above 1 does not create an increase in the extraction extent of Cu2+. When the initial pH of the leach solution is higher than 1, the amount of Zn2+ transferred from the aqueous phase to the organic phase increases significantly.[Figure not available: see fulltext.].
AtıfScopus7WoS5OpenAlex9İncele - MakaleYalnız künye2021Scopus SJRQ1Effect of waste textile dye adsorbed almond shell on self compacting mortar
Cemalgil, Selim; Onat, Onur; Tanaydın, Mehmet Kayra; Etli, Serkan
The aim of the current experimental study is to investigate the effect of waste textile dye absorbed almond shell on fresh and mechanical characteristics of self-compacting mortar (SCMs). In this context, eight SCMs were designed by substituting Violet Dye Solution adsorbed Almond shell (VDSA) at the rate of 0%, 2.5%, 5.0%, 7.5%, 10.0%, 12.5%, 15.0% and 17.5% as a cement on weight basis including the control mix. To measure the rheological properties of SCMs, mini slump and V-Funnel tests were conducted. A total of 72 beams of 40x40x160 mm3 dimension specimens were casted and immersed in water curing at the end of the 7, 28 and 56 days to determine the mechanical parameters. 48 cubes of 50x50x50 mm3 dimensions were casted and kept in the curing tank to determine durability characteristics such as porosity, sorptivity and specific gravity. Quantitative analyses are also performed by using Scanning Electron Microscopes (SEM), X-ray Diffraction Analysis (XRD), Energy-Dispersive X-ray Spectroscopy (EDS) and Fourier Transform Infrared (FTIR). The experimental results indicated that as the content of VDSA enchases, a remarkable enhancement in flexural strength at early days age and 28 days age strength. Whereas, increasing the content of VDSA resulted in a considerable decrease in compressive strength higher than 5%.
AtıfScopus20WoS16OpenAlex26İncele - MakaleYalnız künye2020Scopus SJRQ3Kinetic models for the extraction of copper by Acorga M5640 after leaching of malachite ore in perchloric acid solutions and the stripping of copper from loaded organic phase
Tanaydın, Mehmet Kayra; Demirkıran, Nizamettin
In the present work, the extraction kinetics of copper using the resulting actual leach solution obtained from the leaching of malachite ore in perchloric acid solutions and the stripping kinetics of copper from the loaded organic phase were examined. The organic phase was prepared by using Acorga M5640 and kerosene. In the extraction process, the effects of the initial pH of aqueous solution, initial concentration of copper, extractant concentration, temperature, and stirring speed on the extraction rate were investigated. In the stripping process, the effects of the concentration of perchloric acid, temperature, stirring speed, and extractant concentration on the stripping rate were examined. It was determined that the extraction rate increased with increasing the initial pH of aqueous solution, stirring speed, extractant concentration and temperature, and with decreasing the initial concentration of copper ions. In the stripping process, it was observed that the stripping rate increased with increasing the concentration of perchloric acid, temperature and stirring speed, and with decreasing the extractant concentration. It was determined that both the solvent extraction and stripping processes could be described by the first order pseudo homogenous reaction model. The activation energy for the extraction and stripping processes was calculated to be 50.04 kJ/mol and 32.42 kJ/mol, respectively.
AtıfScopus8WoS7OpenAlex10İncele - MakaleYalnız künye2019Scopus SJRQ2Investigation of selective leaching and kinetics of copper from malachite ore in aqueous perchloric acid solutions
Tanaydın, Mehmet Kayra; Demirkıran, Nizamettin
In this study, the leaching kinetics of malachite in perchloric acid solutions was investigated. The dissolution behaviors of copper, zinc, and iron in the ore matrix were determined at different acid concentrations and reaction temperatures. It was observed that the concentration of perchloric acid had a major effect on the dissolution of copper, zinc, and iron. It was determined that the effect of temperature on the dissolution of these species was not as significant as concentration impact. The results obtained shown that copper in the ore matrix was completely leached while zinc and iron were partially dissolved in perchloric acid solutions. In addition, the effects of the acid concentration, reaction temperature, stirring speed, particle size, and solid-to-liquid ratio on the leaching of malachite were researched. In these experiments, it was observed that the leaching rate of copper increased with increasing solution concentration, stirring speed, and reaction temperature, and with decreasing solid-to-liquid ratio and particle size. A kinetic analysis was performed, and it was found that the rate of leaching reaction obeyed the mixed kinetic control model in the unsteady state. The activation energy of the leaching process was calculated to be 34.69 kJ/mol.
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