Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collections

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/3

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Now showing 1 - 8 of 8

Citation - WoS: 11
Citation - Scopus: 9
Capture and Release Recyclable Dimethylaminomethyl-Calixarene Functional Cloths for Point-Of Removal of Highly Toxic Chromium Water Pollutants
(AMER CHEMICAL SOC, 2020) Bieber, Vera S.; Özçelik, Egemen; Cox, Harrison J.; Ottley, Christopher J.; Ratan, Jatinder K.; Karaman, Mustafa; Badyal, Jas Pal S.
Chromium(VI) contamination of drinking water arises from industrial activity wherever there is a lack of environmental legislation enforcement regarding the removal of such pollutants. Although it is possible to remove such harmful metal ions from drinking water through large-scale facilities, there currently exists no safe and simple way to filter chromium(VI) oxoanions at the point of use (which is potentially safer and necessary in remote locations or humanitarian scenarios). High-surface-area cloth substrates have been functionalized with calixarene molecules for the selective capture of aqueous chromium(VI) oxoanions in the presence of structurally similar anions. This is accomplished by pulsed plasmachemical deposition of a linker layer and subsequent functionalization with dimethylaminomethyl-calixarene (5,11,17,23-tetrakis [(dimethylamino)methyl]-25,26,27,28-tetrahydroxycalix[4]arene. Chromium(VI) oxoanions are captured by simply passing polluted water through the functionalized cloth, while other ions not harmful/beneficial to human health remain in the water. These cloth filters are simple to use, highly selective, and easily recyclable-thus making them attractive for point-of-use application in geographic regions lacking appropriate wastewater treatment plants or flawed environmental monitoring systems. Chromium(VI) pollutants have been successfully removed from real-world contaminated industrial wastewater streams using the dimethylaminomethyl-calixarene functionalized cloths.
Carbon Nanotube-Supported Bimetallic Core-Shell (m@pd/Cnt (m: Zn, Mn, Ag, Co, V, Ni)) Cathode Catalysts for H2o2 Fuel Cells
(AMER CHEMICAL SOC, 2023) Yapıcı, Burak; Gökdoğan Şahin, Özlem
M@Pd/CNT (M: Zn, Mn, Ag, Co, V, Ni) core-shell and Pd/CNT nanoparticles were prepared by sodium borohydride reduction and explored as cathode catalysts for the hydrogen peroxide reduction reaction. Electrochemical and physical characterization techniques are applied to explore the characteristics of the produced electrocatalysts. The cyclic voltammetry (CV) experiments show that Zn@Pd/CNT-modified electrodes have a current density of 273.2 mA cm(-2), which is 3.95 times higher than that of Pd/CNT. According to the chronoamperometric curves, Zn@Pd/CNT has the highest steady-state current density for the H2O2 electro-reduction process among the synthesized electrocatalysts. Moreover, electrochemical impedance spectroscopy (EIS) spectra confirmed the previous electrochemical results due to the lowest charge transfer resistance (35 Omega) with respect to other electrocatalysts.
Citation - WoS: 66
Citation - Scopus: 68
Efficient Vacuum-Deposited Perovskite Solar Cells With Stable Cubic Fa(1)(-X)ma(x)pbi(3)
(AMER CHEMICAL SOC, 2020) Gil-Escrig, Lidon; Dreessen, Chris; Kaya, İsmail Cihan; Kim, Beom-Soo; Palazon, Francisco; Sessolo, Michele; Bolink, Henk J.
Preparation of black formamidinium lead iodide (FAPbI(3)) requires high-temperature annealing and the incorporation of smaller A-site cations, such as methylammonium (MA(+)), cesium, or rubidium. A major advantage of vacuum processing is the possibility to deposit perovskite films at room temperature (RT), without any annealing step. Here we demonstrate stabilization of the cubic perovskite phase at RT, in a three-source co-sublimation method. We found that the MA(+) incorporation is a self-limiting process, where the amount of MA(+) which is incorporated in the perovskite is essentially unvaried with increasing MAI deposition rate. In this way a phase-pure, cubic perovskite with a bandgap of 1.53 eV can be obtained at room temperature. When used in fully vacuum-processed perovskite solar cells, PCEs up to 18.8% are obtained. Despite the presence of MA(+), the solar cells were found to be thermally stable and maintained 90% of their initial efficiency after 1 month of continuous operation.
Citation - WoS: 28
Citation - Scopus: 25
Initiated Chemical Vapor Deposition of Poly(ethylhexyl Acrylate) Films in a Large-Scale Batch Reactor
(AMER CHEMICAL SOC, 2019) Yılmaz, Kurtuluş; Şakalak, Hüseyin; Gürsoy, Mehmet; Karaman, Mustafa
The present study demonstrates the successful deposition of poly(ethylhexyl acrylate) thin films in a large-scale closed-batch initiated chemical vapor deposition (iCVD) system. A horizontal cylindrical stainless-steel vacuum tank, which is highly utilized in industrial vacuum applications, was used as iCVD reactor. The effects of substrate temperature, precursor ratio, and pressure on the deposition rates were studied, and the results showed that a deposition rate of 315 nm/min can be achieved in a single run at a reactor pressure of 600 mTorr. At a lower chamber pressure of 400 mTorr, deposition rate decreases, whereas film uniformity increases. By carrying out depositions at successive cycles, thicker films could be obtained, without the need for extensive monomer consumption. The yield percentage was found to be 3.5 for the films deposited in closed-batch system at 400 mTorr, which is 35-fold larger than that of the classical iCVD flow system.
Citation - WoS: 28
Citation - Scopus: 29
Separation of Formic Acid From Aqueous Solutions Onto Anion Exchange Resins: Equilibrium, Kinetic, and Thermodynamic Data
(AMER CHEMICAL SOC, 2019) Zeidan, Hani; Martı, Mustafa Esen
Wastewaters containing organic compounds such as acids, ketones, phenols, and amines can cause critical environmental problems depending on their concentration and composition. Efficient and low-cost separation of these components may also bring their reuse in industry while cleaning the aqueous streams. Formic acid (FA) is an important raw material in industry and is widely seen in wastewaters. In this study, two different anion exchangers were compared for the separation of FA from aqueous solutions. Effects of process parameters and the mechanism were discussed. Kinetic, equilibrium, and thermodynamic studies were performed, and the data were interpreted using the relevant isotherm and kinetic models. The results showed that Lewatit MP-64 was more efficient than Amberlite IRA-96 in the range of the parameters studied. The maximum adsorption capacity obtained with Lewatit MP-64 (442.75 mg/g) was significantly higher than that were previously reported in the literature for FA separation. The data were well explained by the Langmuir isotherm model. However, relatively high R-2 values were obtained with Temkin and Freundlich isotherms. Therefore, further studies are ongoing to clarify the mechanism.
Citation - WoS: 13
Citation - Scopus: 15
Shear Performance in Reinforced Concrete Beams With Partial Aggregate Substitution Using Waste Glass: a Comparative Analysis Via Digital Imaging Processing and a Theoretical Approach
(AMER CHEMICAL SOC, 2024) Zeybek, Özer; Basaran, Bogachan; Aksoylu, Ceyhun; Karalar, Memduh; Althaqafi, Essam; Beskopylny, Alexey N.; Stel'makh, Sergey A.
The usage of waste glass aggregate (WGA) associated with the replacement of fine aggregate (FA) and coarse aggregate (CA) is observed to reduce the number of raw materials for sustainable concrete. For this aim, a total of 15 beams were produced, and then investigational experiments were implemented to observe the shear performances. The stirrup spacing and WGA proportion were chosen as the main parameters. FA and CA were exchanged with WGA with weight proportions of 0, 10, and 20%. The experimental investigation results showed that changing stirrup spacing and WGA proportion affected the fracture and shear properties of reinforced-concrete-beams (R-C-Bs). Furthermore, the findings of the test results revealed that the proportion of WGA could be efficiently consumed as 20% of the partial replacement of FA. With the addition of FA to the mixture, the load carrying capacity of R-C-Bs increases. On the other hand, increasing the WGA ratio by more than 10% using CA, together with increasing the stirrup spacing, can significantly reduce the capacity of R-C-Bs. It was observed that the calculated shear strengths of R-C-Bs with inadequate stirrup spacing, based on ACI 318 and EC2 design codes, can be up to 52 and 79% higher than the experimental results for R-C-Bs containing coarse glass aggregate and 21 and 56% higher for R-C-Bs containing fine glass aggregate, respectively. Additionally, an image processing method was applied to describe the damages/microdamages in R-C-Bs. At that point, the findings obtained from the experimental part of the study were confirmed by the results of the image processing method. Although the strains obtained with the image processing method are reliable, it has not been determined exactly where the crack will occur due to the very sudden development of the shear crack at the moment of beam failure.
Citation - WoS: 9
Citation - Scopus: 11
Utilization of in Situ Fbrm and Pvm Probes To Analyze the Influences of Monopropylene Glycol and Oleic Acid as Novel Additives on the Properties of Boric Acid Crystals
(AMER CHEMICAL SOC, 2020) Kutluay, Sinan; Ceyhan, Ayhan Abdullah; Şahin, Ömer; İzgi, Mehmet Sait
The aim of this study was to determine the influences of monopropylene glycol (MPG) and oleic acid (OA) as novel additives on the chord length distribution (CLD) and modification of the shape of boric acid crystals in real time with the use of in situ focused beam reflectance measurement (FBRM) and particle vision and measurement (PVM) probes, which were positioned on a continuous mixed-suspension mixed-product removal (CMSMPR) crystallizer at a steady-state value. In this context, the FBRM probe was used to monitor CLD, which is expressed as the cumulative undersize square-weight percentage distribution of boric acid crystals. CLD is statistically proportional to crystal size distribution. The shapes of the boric acid crystals were viewed in real time with an in situ PVM probe. In addition, a scanning electron microscope (SEM) and an optical microscope were used to characterize the shapes of the boric acid crystals produced in the CMSMPR crystallizer. The chemical structures of the boric acid crystals were characterized by Fourier transform infrared (FT-IR) analysis. The population density of the nuclei, the nucleation rate, and the growth rate of the boric acid crystals were also calculated. As a result, it was proved that industrial problems encountered in the production of boric acid crystals by the crystallization process were eliminated especially in the presence of 100 ppm OA and 50 ppm MPG additives by FBRM, PVM, SEM analysis, and number density theory application. This study revealed novel insights into the modification of the shape of boric acid crystals and into the control of CLD in the presence of OA and MPG using in situ FBRM and PVM probes.
Citation - WoS: 20
Citation - Scopus: 19
Vapor Deposition of Transparent Antifogging Polymeric Nanocoatings
(AMER CHEMICAL SOC, 2021) Yılmaz, Kurtuluş; Gürsoy, Mehmet; Karaman, Mustafa
This study demonstrates the coating of a transparent and robust organic thin film having an excellent hydrophilicity-based antifogging property by an initiated chemical vapor deposition (iCVD) method. iCVD was able to synthesize linear and cross-liked poly(acrylic acid) (PAA) from the vapors of acrylic acid (AA) and ethylene glycol dimethacrylate (EGDMA) using tert-butyl peroxide (TBPO) as an initiator. High deposition rates of up to 35 nm/min were observed at low deposition temperatures. It was possible to control the quantity of comonomers in the as-deposited films by adjusting the partial pressure of the EGDMA cross-linking agent. The effect of the EGDMA partial pressure on chemical structure was studied using Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) techniques. FTIR and XPS spectra of the as-deposited films showed the complete retention of the monomer functionality during iCVD. Hydrophilicities and large-area uniformity of the coatings were revealed using water contact angle measurements. The as-deposited PAA film was the most hydrophilic with a water contact angle (WCA) of 7.0 degrees, while cross-linking with EGDMA increased the WCA values by up to 51.7 degrees. Results of various tests, which were based on exposing the coated surfaces to artificial fog and hot water vapor, showed the excellent antifogging property of the coatings. Films were never fogged upon extensive and long-term exposure (2 months) to humid air.

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