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    Comparison of ZnO doped different phases TiO2 nanoparticles in terms of toxicity using zebrafish (Danio rerio)
    (Pergamon-Elsevier Science Ltd, 2023) Sezer, Selda; Yucel, Aysegul; Turhan, Duygu Ozhan; Emre, Fatma Bilge; Sarikaya, Musa
    Titanium dioxide is used in many commercial and industrial areas such as paint, paper, cosmetics, textiles, and surface coating. The reasons for its use in such a wide area are its anti-corrosion and high stability. Although TiO2 is considered to be a low-toxicity material, research has been further expanded following the recognition of the possible carcinogenic effects of TiO2 in humans by the International Agency for Research on Cancer (IARC). The aim of this study is to compare the toxicity of TiO2 used in many fields in different phases. In the study anatase TiO2 synthesized by hydrothermal method and dual phase TiO2 (anatase and rutile phase) structures obtained by thermal conditioning were used and compared with commercially available TiO2. ZnO which has similar uses like TiO2 was also used and compared with 1% doped TiO2 in different phases in terms of toxicity. Zebrafish (Danio rerio, D. rerio), a freshwater fish, which is widely used in toxicity assessments was preferred in this study due to its small size, fast reproduction rate, low cost, physiological and molecular similarity with humans, and genetic predisposition. Experimental investigations showed that the highest death occurred in the low concen-trations of (10 ppm) ZnO doped rutile phase. 39% of the embryos died in the ZnO nanoparticle solutions pre-pared at low concentrations. The highest mortality at medium (100 ppm) and high (1000 ppm) concentrations were observed in the ZnO-doped rutile phase after 96 h. Similarly, the highest malformation was detected in the ZnO-doped rutile phase during the same period.
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    Computational Chemistry Approach to Interpret the Crystal Violet Adsorption on Golbasi Lignite Activated Carbon
    (Iop Publishing Ltd, 2016) Depci, Tolga; Sarikaya, Musa; Prisbrey, Keith A.; Yucel, Aysegul
    In this paper, adsorption mechanism of Crystal Violet (CV) dye from the aqueous solution on the activated carbon prepared from Golbasi lignite was explained and interpreted by a computational chemistry approach and experimental studies. Molecular dynamic simulations and Ab initio frontier orbital analysis indicated relatively high energy and electron transfer processes during adsorption, and molecular dynamics simulations showed CV dye molecules moving around on the activated carbon surface after adsorption, facilitating penetration into cracks and pores. The experimental results supported to molecular dynamic simulation and showed that the monolayer coverage occurred on the activated carbon surface and each CV dye ion had equal sorption activation energy.
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    Mineralogical and Chemical Characterization of Acidic Pumices Outcrop North of Lake Van
    (Iop Publishing Ltd, 2016) Yucel, Aysegul; Efe, Tugba; Onal, Mehmet; Depci, Tolga; Aydin, Harun
    In the present study, mineralogical, physical and chemical characteristics of the pumice located in North of Lake Van locations were investigated to find an applicability of them for cement and textile industry. Characterization studies of the pumice samples were carried out by thin section, SEM, XRF, XRD and FTIR analysis. In addition, the bulk density, Hard Grove Index (HGI), pozzolanic activity and reactive silica of the pumice samples were determined. The overall results showed that the pumice samples, which might be an eruption product of Mount Suphan, had an amorphous structure and rhyolite composition in high calcalkaline series. The chemical compositions and physical properties indicated that the pumice samples could be used in cement and textile industry.
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    Production of Nano Amorphous SiO2 from Malatya Pyrophyllite
    (Iop Publishing Ltd, 2016) Sarikaya, Musa; Depci, Tolga; Aydogmus, Ramazan; Yucel, Aysegul; Kizilkaya, Nilgun
    Pyrophyllite (Al4Si8O20(OH)(4)) is an important industrial clay mineral. In this paper, highly pure nano silica powder was synthesized by alkaline treatment method from the local pyrophyllite deposit which is in Malatya, Turkey. The morphologies, structures and properties of the raw pyrophyllite and the obtained nano amorphous SiO2 were determined by XRF, XRD, ATR, SEM and EDX. The results showed that the nano silica can be produced with a high purity (98%) and nano size (< 50 nm).
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    Synthesis and characterization of whitlockite from sea urchin skeleton and investigation of antibacterial activity
    (Elsevier Sci Ltd, 2021) Yucel, Aysegul; Sezer, Selda; Birhanli, Emre; Ekinci, Tuba; Yalman, Emine; Depci, Tolga
    In the present study, undoped whitlockite and ZnO doped-Whitlockite, which is the second most abundant inorganic material in bone structure, were synthesized from sea urchin skeleton. The obtained bioceramic ma-terials were characterized by XRD, FT-IR, and SEM and their antibacterial activities were determined using the inhibition zone diameters of Escherichia coli and Pseudomonas aeruginosa as gram negative bacteria and Staphylococcus aureus as gram positive bacterium after 24 h incubation. The characterization studies showed that nano size homogenous biocereamic whitlockite (Ca2.86Mg0.14(PO4)(2)) was synthesized from the sea urchin skeleton. After dopping process, the main structure of the whitlockite keeps stable, showing a dopping concentration-independent character. On the other hand, the peaks belonging to ZnO were started to seen in the XRD pattern with increasing the level of ZnO-concentration (after 7 %). All experimental results point out that the obtained whitlockites are viable nominate candidates for bioceramic materials and the results of antibacterial sensitivity prove the inhibitory effect towards Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus for ZnO-doped-whitlockite.
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    Usability of Malatya Pyrophyllite in the Traditional Ceramic Industry
    (Iop Publishing Ltd, 2016) Kizilkaya, Nilgun; Onal, Mehmet; Depci, Tolga; Yucel, Aysegul
    In the present study, the usability of the pyrophyllite in the traditional ceramic industry was investigated. The raw pyrophyllite was obtained in Malatya, Turkey. The characterization of the raw pyrophyllite and the prepared ceramics which were heated at the different temperatures in oven (800, 900, 1000 and 1100 degrees C) were done by XRF, XRD, FTIR, SEM and the main physical properties, like total shrinkage, water absorption capacity and compression strength were determined. As a result of experimental studies; the raw pyrophyllite had to be mixed with the feldspar and another clay (Unye clay) with having high plasticity in order to shape easily and a high water resistance. The optimum receipt was found as 70 wt % pyrophyllite, 20 wt % Unye clay and 10 wt % feldspar. The main properties of the obtained ceramics were specific white baking colour and high temperature resistance properties.