Bestami Ozkaya
Yıldız Technical University
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Publication
Featured researches published by Bestami Ozkaya.
Bioresource Technology | 2015
Afsin Y. Cetinkaya; Oguz Kaan Ozdemir; Emre Oguz Koroglu; Aydin Hasimoglu; Bestami Ozkaya
Performance of cathode materials in microbial fuel cell (MFC) from dairy wastewater has been investigated in laboratory tests. Both cyclic voltammogram experiments and MFC tests showed that Pt-Ni cathode much better than pure Pt cathode. MFC with platinum cathode had the maximum power density of 0.180 W m(-2) while MFC with Pt:Ni (1:1) cathode produced the maximum power density of 0.637 W m(-2), even if the mass mixing ratio of Pt is lower in the alloy were used. The highest chemical oxygen demand (COD) removal efficiency was around 82-86% in both systems. The cyclic voltammogram (CV) analyses show that Pt:Ni (1:1) offers higher specific surface area than Pt alone does. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) results showed that entire Pt:Ni (1:1) alloys can reduce the oxygen easily than pure platinum, even though less precious metal amount. The main outcome of this study is that Pt-Ni, may serve as a alternative catalyst in MFC applications.
International Journal of Dairy Technology | 2015
Dogan Karadag; Oguz Emre Köroğlu; Bestami Ozkaya; Mehmet Cakmakci; S. Heaven; C.J. Banks; Alba Serna-Maza
Considerable research has been conducted on the treatment of dairy wastewater by anaerobic granular reactors. Upflow anaerobic sludge blanket (UASB) reactors, anaerobic sequencing batch reactors (ASBR) and static granular bed reactors (SGBR) are the conventional granular reactor types most commonly applied in dairy wastewater treatment. Hybrid systems have also been developed to increase treatment efficiency and overcome the operational problems associated with the treatment of this substrate. Effects of parameters including temperature, organic loading and operating protocols on the performance of granular reactors are summarised. Individual and hybrid granular reactors are evaluated based on organic matter removal and methane production capacity.
Energy Sources Part A-recovery Utilization and Environmental Effects | 2016
Afsin Y. Cetinkaya; Bestami Ozkaya; Ergin Taskan; Dogan Karadag; Mehmet Cakmakci
ABSTRACT In this study, electricity production from old age landfill leachate was investigated using dual chambered microbial fuel cell with Ti-TiO2 electrodes. The effect of organic loading rate on microbial fuel cell performance was examined by changing the hydraulic retention time and leachate chemical oxygen demand (COD) concentration. Microbial diversity at different conditions was studied using PCR-DGGE profiling of 16 sRNA fragments of microorganisms in the liquid media of the anode chamber and of the biofilm on the anode electrode. Both COD removal and current density were positively affected with increasing organic loading rate. The highest microbial fuel cell performance was achieved at hydraulic retention time of 0.5 day and organic loading rate of 10 g COD/L.day. The performance of the microbial fuel cell reactor decreased when hydraulic retention time was reduced to 0.25 day. The investigation of the microbial dynamics indicated that abundance of bacterial species was considerably dependent on the operational conditions. The microbial fuel cell reactor was mainly dominated by Geobacter, Shewanella, and Clostridium species, and some bacteria were easily washed out at lower hydraulic retention times.
Chemical Papers | 2017
Harun Elcik; Mehmet Cakmakci; Bestami Ozkaya
In this study, hydrophilic and fouling-resistant polysulfone (PS) membranes were fabricated using the phase inversion method to reduce membrane fouling caused by microalgal culture. The Pluronic F-127 polymer, which is used as a hydrophilic co-polymer, was added to the membranes to improve the membrane properties. Characteristic specifications of the fabricated membranes, such as morphology, surface roughness, chemical structures and hydrophobicity/hydrophilicity, were studied using scanning electron microscopy, atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), attenuated total reflection-fourier infrared (ATR-FTIR) spectroscopy and contact angle devices. According to the results obtained, it was observed that, with the increase of the Pluronic F-127 concentration in the membranes, the surface roughness of the membranes decreased and hydrophilicity and permeation fluxes increased notably. Furthermore, it was observed that the addition of the Pluronic F-127 polymer into the membranes reduced reversible/irreversible membrane fouling. Additionally, a characterisation of the fouled membranes was performed for the purpose of comprehensively understanding the membrane fouling mechanism caused by microalgal culture.
Archive | 2019
Hulya Civelek Yoruklu; Emre Oguz Koroglu; Ahmet Demir; Bestami Ozkaya
Abstract This chapter introduces the electrofermentation (EF) method that could be an important process for the fermentation applications in the future. It starts with a brief description of fermentation and detailed description of the working principle of bioelectrochemical systems. It then explains EF process from past and today. Also, the working principle of the EF process and the benefits it provides in terms of quantity and quality of products are explained in detail. By the end of the chapter, potential use of EF in industrial applications and future prospects are mentioned. The advantages of the EF process is discussed by taking into account the parameters that are effective in the quality and yield of the product in the conventional fermentation process.
Process Biochemistry | 2015
Dogan Karadag; Oguz Emre Köroğlu; Bestami Ozkaya; Mehmet Cakmakci
Renewable & Sustainable Energy Reviews | 2016
Sai Kishore Butti; G. Velvizhi; Mira L.K. Sulonen; Johanna M. Haavisto; Emre Oguz Koroglu; Afsin Y. Cetinkaya; Surya Prakash Singh; Divyanshu Arya; J. Annie Modestra; K. Vamsi Krishna; Anil Verma; Bestami Ozkaya; Aino-Maija Lakaniemi; Jaakko A. Puhakka; S. Venkata Mohan
International Biodeterioration & Biodegradation | 2013
Dogan Karadag; Bestami Ozkaya; Esra Ölmez; Marika E. Nissilä; Mehmet Cakmakci; Şenol Yıldız; Jaakko A. Puhakka
Journal of Chemical Technology & Biotechnology | 2014
Dogan Karadag; Oguz Emre Köroğlu; Bestami Ozkaya; Mehmet Cakmakci; S. Heaven; C.J. Banks
Separation and Purification Technology | 2015
Arda Karluvalı; Emre Oguz Koroglu; Neslihan Manav; Afsin Y. Cetinkaya; Bestami Ozkaya