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- ArticleYalnız künye2026Removal of Malachite Green from Aqueous Solutions by Using Bi4V2O11 Nanosheet
Yavuz, Emre; Dundar, Ozan Ali; Yavuz, Sevtap Caglar; Yilmaz, Erkan; Ozdokur, Kemal Volkan; Cirak, Burcu Bozkurt; Caglar, Bulent; Cirak, Cagri; Arar, Özgür
Introduction: Transition metal oxides are highly effective for dye removal due to their adaptable surface chemistry, availability, and robust mechanical and thermal properties. Among them, Bi4V2O11 nanosheets offer potential due to their morphology and high surface area. To synthesize Bi4V2O11 nanosheets and evaluate their performance in removing malachite green, focusing on the impact of adsorbent amount, contact time, and interfering ions on dye removal efficiency. This study aims to evaluate the performance of Bi4V2O11 nanosheets in removing malachite green dye from aqueous solutions and to examine the effects of adsorbent dosage, contact time, and the presence of coexisting ions on the sorption process. Methods: Bi4V2O11 nanosheets were synthesized and used to remove the malachite green dye. Batch experiments were conducted to study the effects of adsorbent dose, contact time, and coexisting ions (Na+, Ca2+, and tannic acid). Equilibrium data were fitted to the Langmuir isotherm model to determine the maximum sorption capacity. Results: Malachite green sorption using Bi4V2O11 nanosheets reached equilibrium within 240 minutes, demonstrating efficient dye removal under the tested conditions. The sorption process conformed to the Langmuir isotherm model, indicating monolayer adsorption with a maximum capacity of 47.27 mg/g. While the presence of Na+ and tannic acid had negligible effects on dye removal efficiency, the coexistence of Ca2+ significantly reduced the removal efficiency from 95% to 58%, highlighting the potential impact of divalent ions on the adsorption process. Discussion: Bi4V2O11 nanosheets are effective adsorbents for malachite green removal, demonstrating high sorption capacity and resilience to Na+ and tannic acid interference. However, the presence of Ca2+ significantly reduces removal efficiency, highlighting the need for further optimization in practical applications. Conclusion: Bi4V2O11 nanosheets offer high sorption capacity and structural stability, environment friendly synthesis procedure, making them feasible for small-scale or pre-treatment applications. 2026, Bentham Science Publishers
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2026ZnBi2O4/Ag2WO4 nanocomposite for efficient photocatalytic removal of dye and pharmaceutical pollutants
Yavuz, Sevtap Caglar; Emul, Zeynep; Icer, Fatih; Yavuz, Emre; Ozdokur, Volkan Kemal; Cirak, Burcu Bozkurt
This paper targets to synthesize a nano-composite with high photocatalytic performance and research the possibility of utilizing it for dye and drug removal from wastewater. Herein, ZnBi2O4/Ag2WO4 nanocomposite photocatalyst was successfully synthesized via two step hydrothermal/precipitation method. The photocatalytic activity of the synthesized nanocomposite was evaluated by its effect on the degradation of methylene blue dye and sulfamerazine drug under UV light. The results revealed that the ZnBi2O4/Ag2WO4 nanocomposite achieved a significantly higher photocatalytic efficiency (96% degradation of methylene blue in 1 h) compared to ZnBi2O4 (41%) and Ag2WO4 (76%) within only 60 min. The exceptional photocatalytic degradation efficiency of the ZnBi2O4/Ag2WO4 nanocomposite against methylene blue and sulfamerazine can be attributed to the effects of reduced charge carrier recombination resulting from the synergistic effect of surface adsorption-photocatalytic degradation interaction of ZnBi2O4 and Ag2WO4.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2025Superior photocatalytic performance of ZnMoO4/Ag2WO4 for degradation of trimethoprim and methylene blue
Yavuz, Sevtap Caglar; Yavuz, Emre; Ozdokur, Kemal Volkan
In the present work, ZnMoO4/Ag2WO4 nanocomposite was synthesized via facile hydrothermal and chemical precipitation method for determination of photocatalytic performance on organic contaminants such as methylene blue and trimethoprim. The synthesized nano-photocatalyst was characterized using various instrumental techniques. Photocatalytic degradation of methylene blue and trimethoprim by the samples was realized under UV light irradiation. The obtained results demonstrated that photocatalytic degradation of methylene blue by ZnMoO4/Ag2WO4 was 99.6% in 30 min. The bare ZnMoO4 produced 57.8% and Ag2WO4 produced 76.7% photocatalytic degradation of methylene blue in 60 min. The synthesized ZnMoO4/Ag2WO4 nanocomposite, about which there is little information on remediation of organic pollutants, had possessed the outstanding photocatalytic degradation performance on methylene blue and trimethoprim due to pseudo first order kinetic.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2025Solvothermal synthesis of ZnV2O6/g-C3N4 composites for high-performance supercapacitors
Yaldır, Onur; Karabiberoğlu, Şükriye; Koçak, Çağrı Ceylan; Yavuz, Emre; Özdokur, Kemal Volkan; Dursun, Zekerya
Composite materials formed by combining mixed metal oxides and graphitic carbon nitride have gained significant attention in recent years for energy applications. Here, a novel material was obtained by combining ZnV2O6 mixed metal oxide structure synthesized by the solvothermal method with g-C3N4 prepared by pyrolysis. SEM, XPS, XRD, FTIR, and TGA techniques were employed for comprehensive material characterization. The synthesized ZnV2O6/g-C3N4 was then used in supercapacitor studies. The resulting composite material demonstrated a specific capacity of 438 F g−1 at 1.5 A g−1 in 6.0 M KOH solution. After 2500 cycles, it retains 96 % of its capacitance, demonstrating excellent cyclic stability. Furthermore, a symmetric supercapacitor device based on ZnV₂O₆/g-C₃N₄ electrodes was assembled and tested, achieving high capacitance retention over extended charge–discharge cycles. The synergistic effect of g-C3N4, with its large surface area and chemical stability, and ZnV2O6, with its fast electron transfer ability, has resulted in the formation of the composite with enhanced performance.
RDL Kalıcı Kaydıİncele - Review ArticleYalnız künye2024Use of transition metal dichalcogenides (TMDs) in analytical sample preparation applications
Yilmaz, Erkan; Yavuz, Emre
Since the discovery of graphene, nano-sized two-dimensional (2D) transition metal dichalcogenides (TMDs) such as MoS2, MoSe2, MoTe2, NbS2, NbSe2, WS2, WSe2, TaS2 and TaSe2, which have been classified as next-generation nanomaterials resembling graphene (G) have complementary basic properties with those of graphene in terms of their practical applications. TMDs are attracting great attention due to their attractive physical, chemical and electronic properties. Despite being overshadowed by graphene in terms of frequency of use, TMDs have been used frequently in many areas in recent years instead of carbon-based materials such as graphene (G), graphene oxide (GO), carbon nanotubes (CNTs) and nanodiamonds (NDs). It is seen that the first and frequent uses of TMDs, which are classified as new generation materials, are in the fields of catalysis, electronic applications, hydrogen production processes and energy storage, but it has been used as an adsorbent in sample preparation techniques in recent years. Similar to graphene, layers of TMDs are held together by weak van der Waals interactions. The sandwiched layers of TMDs provide sufficient and effective interlayer spaces so that foreign molecules, ions and atoms can easily enter these spaces between the layers. Intermolecular interactions increase with the entry of different materials into these spaces, and thus, high activity, adsorption capacity and efficiency are obtained in adsorption-based analytical sample preparation methods. Although there are about 35 research articles using TMDs, which are classified as promising materials in analytical sample preparation techniques, no review studies have been found. This review, which was designed with this awareness, contains important informations on the properties of metal dichalcogenides, their production methods and their use in analytical sample preparation techniques.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024AuNPs with Cynara scolymus leaf extracts rescue arsenic-induced neurobehavioral deficits and hippocampal tissue toxicity in Balb/c mice through D1R and D2R activation
Cicek, Betul; Hacimuftuoglu, Ahmet; Yeni, Yesim; Kuzucu, Mehmet; Genc, Sidika; Cetin, Ahmet; Yavuz, Emre; Danısman, Betul; Levent, Akin; Ozdokur, Kemal Volkan
The present study was designed to evaluate whether AuNPs (gold nanoparticles) synthesized with the Cynara scolymus (CS) leaf exert protective and/or alleviative effects on arsenic (As)-induced hippocampal neurotoxicity in mice. Neurotoxicity in mice was developed by orally treating 10 mg/kg/day sodium arsenite (NaAsO2) for 21 days. 10 µg/g AuNPs, 1.6 g/kg CS, and 10 µg/g CS-AuNPs were administered orally simultaneously with 10 mg/kg As. CS and CS-AuNPs treatments showed down-regulation of TNF-α and IL-1β levels. CS and CS-AuNPs also ameliorated apoptosis and reduced the alterations in the expression levels of D1 and D2 dopamine receptors induced by As. Simultaneous treatment with CS and CS-AuNPs improved As-induced learning, memory deficits, and motor coordination in mice assessed by water maze and locomotor tests, respectively. The results of this study provide evidence that CS-AuNPs demonstrated neuroprotective roles with antioxidant, anti-inflammatory, and anti-apoptotic effects, as well as improving D1 and D2 signaling, and eventually reversed neurobehavioral impairments.
RDL Kalıcı Kaydıİncele - Review ArticleYalnız künye2024Advancements in reusable SERS substrates for trace analysis applications
Yavuz, Emre; Sakir, Menekse; Onses, M. Serdar; Salem, Samaa; Yilmaz, Erkan
Surface Enhanced Raman Spectroscopy (SERS) technique is an effective analytical technique in which fingerprint information about analytes can be obtained, can provide detection limit performance at the single molecule level, and analyzes are performed in a single step without any intermediate steps. SERS technique offers additional benefits rather than other analytical techniques including high selectivity, ultrasensitive detection, uncomplicated protocols, in situ sampling, on-set capability and cost-effectiveness. As a result of the combination of developments in materials and nanotechnology science with the SERS analysis technique, this technique strengthens its use advantage day by day. The most important factor that limited the use of this technique was the fact that the solution containing the desired analyte(s) was dropped onto the SERS substrate and the same substrate could not be reused in subsequent analyses. To solve this problem, scientists have focused on developing reusable SERS substrates in recent years. In these studies, scientists basically used three SERS substrate cleaning applications (1) washing the SERS substrate with a suitable solvent that can elute the analyte from SERS surface after analysis, (2) cleaning the SERS substrate with catalytic degradation of analytes after analysis by modifying them with catalytic active materials and (3) Applying plasma cleaning procedure to SERS substrate after analysis and (4) applying adsorption and desorption procedure prior to SERS analysis. Herein, the aim of this review article is to evaluate the reusable SERS substrates-based methods based on their level of development and their potential to recycle. This review offers a coherent discussion on a wide range of sensing schemes employed in fabricating the SERS substrates. We utilized a critical approach in which elaborative examples were selected to highlight key shortcomings of various experimental configurations. In the same vein, there is a discussion of the advantages and limitations concerning the key instrumental advances and the expansion of the recent methods developed in this area.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Removal of manganese (Mn2+) from water samples using a biocomposite sorbent
Çalışır, Aykut; Çağlar Yavuz, Sevtap; Yavuz, Emre; Arar, Özgür; Arda, Müşerref
Herein, tannic acid–tethered cellulose was developed as an efficient and selective sorbent for Mn2⁺ removal from aqueous solutions. The modified cellulose was characterized through scanning electron microscopy, infrared spectroscopy, and elemental analyses. Sorption performance was evaluated using various parameters, including pH, initial Mn2⁺ concentration, contact time, and the presence of interfering ions. Results indicated that Mn2⁺ removal was highly pH-dependent, with removal efficiency increasing from 8% at pH 2 to99% at pH 9, achieving a remarkable 99% removal rate within only 30 min, highlighting the rapidity of the cellulose sorption kinetics. The results of isotherm studies confirmed that the sorption conformed to the Langmuir model with a monolayer sorption mechanism. Using a sorbent dose of 0.05 g, 99% of Mn2⁺ could be effectively eliminated from water, achieving a maximum sorption capacity of 32.2 mg/g dry-sorbent. The modified cellulose could be effectively regenerated using 0.5-M HCl or 0.1-M H₂SO₄, with no considerable deterioration in sorption performance after three sorption–regeneration cycles. The presence of Na⁺ and K⁺ had minimal impact on Mn2⁺ removal, whereas the presence of Ca2⁺ and Mg2⁺ at low concentrations facilitated moderate-level Mn2⁺ removal.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2023Microwave-Assisted Fabrication of Pd, Co and Ni Nanoparticles Modified-SiO2; as Catalysts in the Reduction Reaction of Organic Pollutants
Dayan, Serkan; Yavuz, Sevtap Çaglar; Yavuz, Emre
Nanomaterials have been used in catalytic degradation of organic pollutants also act as catalysts in for many years. Due to excellent catalytic performances of metal-based nanoparticles, these materials have been used extensively in various hybrid catalyst synthesis. The main subject of this study, heterogeneous catalysis is a low cost and multi-purpose process for many pollutants. Catalytic degradation of organic pollutants such as; 2-nitrophenol, quinolin yellow and rhodamine B was investigated by using Ni, Co, Pd nanoparticles modified SiO2 based nanomaterials. The co-doping effect on the prepared nanomaterials has been investigated with different characterization methods in terms of structural and morphological features: scanning electron microscopy, UV/vis absorption spectroscopy, energy-dispersive X-ray spectroscopy and foruier-transform infrared spectroscopy. The highest catalytic reduction efficiencies (97.6% and 97.5%) for 2-nitrophenol and rhodamine B was obtained by Pd-PEG-AP@SiO2 respectively. The synthesized Co-PEG-AP@SiO2 illustrated higher catalytic reduction efficiency for quinolin yellow (70.1%) at the end of 60s. The prepared M-PEG-AP@SiO2 nanomaterial (M: Pd,Co,Ni) can be able to utilized degradation of organic contaminants effectively.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2022Ni-Zn metal-organic framework based membranes for rejection of Pb (II) ions
Senol-Arslan, Dilek; Gül, Ayse; Uzal, Nigmet; Yavuz, Emre
The present paper describes a sustainable and affordable supply of clean, and safe water approach to investigate Ni-Zn MOF embedded membrane for rejection of Pb (II) ions in aqueous solution. Ni-Zn MOF powder was prepared by solvo-thermal method, and then the Ni-Zn MOF embedded membranes with various concentrations (0.025 wt%, 0.05 wt% and 0.1 wt%). The membranes were fabricated by a common phase inversion method. Phase solutions of Pb(II) prepared with PVP at different concentrations in aqueous solutions. Water filtration and Pb (II) rejection tests were operated on a batch scale. The prepared Ni-Zn MOF powder characterized by FTIR, SEM-EDX analyses and zeta potential measurements. Ni-Zn MOF membranes were characterized by FTIR, SEM-EDX analysis, contact angle, and water permeability measurements. The effects of important parameters on adsorption including concentration and pH were investigated. The obtained results indicated that the maximum rejection of Pb(II) was 98% for a feed solution containing 80 mg Pb/L at pH 8 and assistance with 2 % PVP for 0.05 wt% Ni-Zn MOF membrane. Additionally, it was detected that blend membranes revealed better Pb(II) rejection than pure PSF membrane.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2022Gold-Nanoparticles-Decorated ZrO2-CuO Nanocomposites: Synthesis, Characterization and A Novel Platform for Electrocatalytic Formaldehyde Oxidation
Özdokur, Kemal Volkan; Koçak, Çağrı Ceylan; Eden, Çiğdem; Demir, Zeynep; Çirak, Çağrı; Yavuz, Emre; Çağlar, Bülent
In this study, gold nanoparticles decorated copper oxide- zirconium oxide mixture has been deposited on glassy carbon electrode surface by simple electrochemical technique. The obtained composite surface has been investigated by electrochemical impedance spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy in detail. The results of SEM images, XPS and XRD data indicated the surface of ZrO2-CuO composite was successfully decorated with Au nanoparticles. The resulting ZrO2-CuO/Au nanocomposite contained about 1.48 % Au nanoparticles with 70 nm average diameter. Then, the catalytic performance of ZrO2-CuO/Au nanocomposites was investigated by using formaldehyde oxidation. The comparative studies have been revealed that the ZrO2-CuO/Au nanocomposites exhibited a better current density towards formaldehyde oxidation than that of bare, ZrO2-CuO, and Au modified electrodes in alkaline media. According to the best of our knowledge, this is the first study dealing with the usage of ZrO2-CuO/Au nanocomposites in formaldehyde oxidation. As the electrochemically fabricated, stable ZrO2-CuO/Au surface improved catalytic activity towards formaldehyde oxidation, this material is a promising candidate for application in fuel cells and removal of formaldehyde from aqueous solutions.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2018Towards secure e-voting using ethereum blockchain
Koç, Ali Kaan; Yavuz, Emre; Çabuk, Umut Can; Dalkiliç, Gökhan; Varol, A.; Karabatak, M.; Varol, C.
There is no doubt that the revolutionary concept of the blockchain, which is the underlying technology behind the famous cryptocurrency Bitcoin and its successors, is triggering the start of a new era in the Internet and the online services. While most people focus only at cryptocurrencies; in fact, many administrative operations, fintech procedures, and everyday services that can only be done offline and/or in person, can now safely be moved to the Internet as online services. What makes it a powerful tool for digitalizing everyday services is the introduction of smart contracts, as in the Ethereum platform. Smart contracts are meaningful pieces of codes, to be integrated in the blockchain and executed as scheduled in every step of blockchain updates. E-voting on the other hand, is another trending, yet critical, topic related to the online services. The blockchain with the smart contracts, emerges as a good candidate to use in developments of safer, cheaper, more secure, more transparent, and easier-to-use e-voting systems. Ethereum and its network is one of the most suitable ones, due to its consistency, widespread use, and provision of smart contracts logic. An e-voting system must be secure, as it should not allow duplicated votes and be fully transparent, while protecting the privacy of the attendees. In this work, we have implemented and tested a sample e-voting application as a smart contract for the Ethereum network using the Ethereum wallets and the Solidity language. Android platform is also considered to allow voting for people who do not have an Ethereum wallet. After an election is held, eventually, the Ethereum blockchain will hold the records of ballots and votes. Users can submit their votes via an Android device or directly from their Ethereum wallets, and these transaction requests are handled with the consensus of every single Ethereum node. This consensus creates a transparent environment for e-voting. In addition to a broad discussion about reliability and efficiency of the blockchain-based e-voting systems, our application and its test results are presented in this paper, too.
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