Researcher:
Balcı, Volkan

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PhD Student

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Volkan

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Balcı

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Balcı, Volkan

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2013 - 201952020 - 20211

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    Short- and long-term thermal stabilities of imidazolium-type ionic liquids on catalytic metal-oxide supports
    (AIChE, 2013) N/A; N/A; Department of Chemical and Biological Engineering; Akçay, Aslı; Balcı, Volkan; Uzun, Alper; Master Student; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 59917
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    Interactions of [BMIM][BF 4] with metal oxides and their consequences on stability limits
    (Amer Chemical Soc, 2016) N/A; N/A; N/A; Department of Chemical and Biological Engineering; Babucci, Melike; Balcı, Volkan; Akçay, Aslı; Uzun, Alper; PhD Student; PhD Student; Master Student; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 59917
    Interactions between 1-n-butyl-3-methylimidazolium tetrafluoroborate, [BMIM][BF4], and high-surface-area metal oxides, SiO2, TiO2, Fe2O3, ZnO, gamma-Al2O3, CeO2, MgO, and La2O3, covering a wide range of point of zero charges (PZC), from pH = 2 to 11, were investigated by combining infrared (IR) spectroscopy with density functional theory (DFT) calculations. The shifts in spectroscopic features of the ionic liquid (IL) upon coating different metal oxides were evaluated to elucidate the interactions between IL and metal oxides as a function of surface acidity. Consequences of these interactions on the short- and long-term thermal stability limits as well as the apparent activation energy (Ea) and rate constant for thermal decomposition of the supported IL were evaluated. Results showed that stability limits and Ea of the IL on each metal oxide significantly decrease with increasing PZC of the metal oxide. Results presented here indicate that the surface acidity strongly controls the IL surface interactions, which determine the material properties, such as thermal stability. Elucidation of these effects offers opportunities for rational design of materials which include direct interactions of ILs with metal oxides, such as solid catalysts with ionic liquid layer (SCILL), and supported ionic liquid phase (SILP) catalysts for catalysis applications or supported ionic liquid membranes (SILM) for separation applications.
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    Thermal stability limits of imidazolium ionic liquids immobilized on metal-oxides
    (Amer Chemical Soc, 2015) N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Babucci, Melike; Balcı, Volkan; Akçay, Aslı; Uzun, Alper; PhD Student; PhD Student; Master Student; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 59917
    Thermal stability limits of 33 imidazolium ionic liquids (ILs) immobilized on three of the most commonly used high surface area metal-oxides, SiO2, gamma-Al2O3, and MgO, were investigated. as were chosen from a family of 13 cations and 18 anions. Results show that the acidity of C2H of an imidazolium ring is one of the key factors controlling the thermal stability. An increase in C2H bonding strength of ILs leads to an increase in their stability limits accompanied by a decrease in interionic energy. Systematic changes in IL structure, such as changes in electronic structure and size of anion/cation, methylation on C2 site, and substitution of alkyl groups on the imidazolium ring with functional groups have significant effects on thermal stability limits. Furthermore, thermal stability limits of ILs are influenced strongly by acidic character of the metal-oxide surface. Generally, as the point of zero charge (PZC) of the metal-oxide increases from SiO2 to MgO, the interactions of IL and metal-oxide dominate over interionic interactions, and metal-oxide becomes the significant factor controlling the stability limits. However, thermal stability limits of some ILs show the opposite trend, as the chemical activities of the cation functional group or the electron donating properties of the anion alter IL/metal-oxide interactions. Results presented here can help in choosing the most suitable ILs for materials involving ILs supported on metal-oxides, such as for supported ionic liquid membranes (SLLM) in separation applications or for solid catalyst with ionic liquid layer (SCILL) and supported ionic liquid phase (SILP) catalysts in catalysis.
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    Catalytic naphtha reforming
    (CRC Press, 2017) N/A; N/A; Department of Chemical and Biological Engineering; Balcı, Volkan; Şahin, İbrahim; Uzun, Alper; PhD Student; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 59917
    Catalytic naphtha reforming (CNR) process was pioneered by UOP in the late 1940s to meet the burgeoning demand for high-octane motor fuels and has been a pivotal unit in petroleum refineries all over the world since its inception. The CNR process is specifically designed to convert naphtha to high-octane gasoline blending components called reformate. The low-octane components that usually have octane number in the range of 40–65 in naphtha, such as normal paraffins (n-paraffins), are converted into isoparaffins (i-paraffins) and naphthenes, and naphthenes are converted to aromatics in catalytic reformers to enhance the octane number of gasoline blends up to 90–105. In order to elaborate the dependency of octane number on chemical structure, numerous hydrocarbons are compared in Table 6.1 with respect to their research octane numbers. In general, aromatics possess the highest octane number, followed by naphthenes, olefins, and n-paraffins having the lowest octane number among other hydrocarbons listed. One of the essential characteristics of the CNR process is that it is the primary source of aromatics, such as benzene, toluene, and xylene (BTX) with more than 50 vol.% of production volume on worldwide basis. Moreover, it produces hydrogen as a by-product (also called net gas as a mixture of hydrogen, methane, ethane, and trace propanes), which can be utilized in hydrogen-consuming processes (i.e., hydrocracking, hydrotreating, hydrogenation, etc.) refinery-wide.
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    MCM-41-supported tungstophosphoric acid as an acid function for dimethyl ether synthesis from CO2 hydrogenation
    (Pergamon-Elsevier Science Ltd, 2021) N/A; Department of Chemical and Biological Engineering; N/A; Department of Chemical and Biological Engineering; Şeker, Betül; Dizaji, Azam Khodadadi; Balcı, Volkan; Uzun, Alper; Researcher; Researcher; PhD Student; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); N/A; College of Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 59917
    We mixed an MCM-41-supported tungstophosphoric acid (TPA) catalyst with a commercial CuO-ZnO Al2O3 methanol synthesis catalyst (MSC) and optimized the mixing ratios/reaction conditions towards high performance in dimethyl ether (DME) synthesis by CO2 hydrogenation. First, a series of TPA/MCM41 catalysts were synthesized at a TPA loading of 30, 40, 60, and 80 wt% and characterized by combining various techniques. The results of X-ray fluorescence spectroscopy confirmed the loading of stoichiometric TPA amounts in each TPA/MCM-41 catalyst, while the N-2 adsorption-desorption measurements and the scanning transmission electron microscopy images were showing the decoration of MCM-41 pores with TPA clusters. X-ray diffraction and infrared spectroscopy results identified some structural distortions in TPA clusters especially at relatively low loadings and the results of temperature programmed desorption of ammonia measurements quantified the consequences of these changes in TPA structure on the acid properties. The optimized TPA loading in TPA/MCM-41 was 60 wt% with CuO-ZnO Al2O3:TPA/MCM-41 = 4:1 at 40 000 mL CO2 g(cat)(-1) h(-1) and H-2:CO2 = 3:1 at 250 degrees C and 45 bar. At these conditions, the rate was 1551.5 gDME kg(cat)(-1) h(-1), to the best of our knowledge, the highest rate for the direct DME synthesis from CO2 hydrogenation in a single-pass reactor. This performance was originated from the high density of acid sites in TPA/MCM-41 owing to exceptionally high surface area of MCM-41 offering a monolayer dispersion of TPA even at a TPA loading of 60 wt%. These results present a broad potential of TPA/MCM-41 as an acid function in the catalyst mixture for the single-pass DME synthesis from CO2 hydrogenation, especially if used together with an MSC specifically designed for CO2 hydrogenation.
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    [BMIM] [PF6] incorporation doubles CO2 selectivity of ZIF-8: elucidation of interactions and their consequences on performance
    (Amer Chemical Soc, 2016) N/A; N/A; N/A; N/A; N/A; Department of Chemical and Biological Engineering; Department of Chemical and Biological Engineering; Kınık, Fatma Pelin; Altıntaş, Çiğdem; Balcı, Volkan; Koyutürk, Burak; Uzun, Alper; Keskin, Seda; Master Student; Researcher; PhD Student; Master Student; Faculty Member; Faculty Member; Department of Chemical and Biological Engineering; Koç University Tüpraş Energy Center (KUTEM) / Koç Üniversitesi Tüpraş Enerji Merkezi (KÜTEM); Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; N/A; N/A; N/A; 59917; 40548
    Experiments were combined with atomically detailed simulations and density functional theory (DFT) calculations to understand the effect of incorporation of an ionic liquid (IL), 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), into a metal organic framework (MOF with a zeolitic imidazolate framework), ZIF-8, on the CO2 separation performance. The interactions between [BMIM] [PF6] and ZIF-8 were examined in deep detail, and their consequences on CO2/CH4, CO2/N-2, and CH4/N-2 separation have been elucidated by using experimental measurements complemented by DFT calculations and atomically detailed simulations. Results suggest that IL-MOF interactions strongly affect the gas affinity of materials at low pressure, whereas available pore volume plays a key role for gas adsorption at high pressures. Direct interactions between IL and MOF lead to at least a doubling of CO2/CH4 and CO2/N-2 selectivities of ZIF-8. These results provide opportunities for rational design and development of IL-incorporated MOFs with exceptional selectivity for target gas separation applications.