Sürdürülebilir Kalkınma Amaçları
Yayınlar
- ArticleAçık Erişim2024Photocatalytic Performances of ZnS/g-C3N4 Nanocomposites with Different Mass Ratios
Caglar, Bulent; Güner, Eda Keles; Doğan, Bilge; Özdemir, Agah Oktay
In this study, we prepared a series of ZnS/graphitic-C3N4 nanocomposites in various mass percentages and morphological properties of all the nanocomposites were examined by utilizing SEM/EDX technique. The photocatalytic performances of ZnS/graphitic-C3N4 nanocomposites were evaluated by degradation of Rhodamine B molecules under visible light. The photocatalytic performances of all nanocomposites under various photocatalyst dosages and initial Rhodamine B concentrations were further investigated for determination of optimal conditions.the obtained results indicated that ZnS/graphitic-C3N4 nanocomposites show almost 2 times higher photocatalaytic performances than pure graphitic-C3N4 and ZnS nanoparticles. The scavenger studies showed that the superoxide radicals had a major role in the photodegradation and the photodegradation of Rhodamine B follows the pseudo-first-order kinetic.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Photocatalytic application of nickel oxide/zinc oxide nanoparticles decorated kaolinite nanocomposite for the degradation of crystal violet
Keles Güner, Eda; Ertugay, Nese; Ozdemir, Agah Oktay; Doğan, Bilge; Caglar, Bulent
The photocatalysis process, which is effective, economical, and environmentally friendly can overcome rapidly increasing environmental problems, has shown rapid development in recent years. Nontoxic, low-cost natural minerals are often used in photocatalysis processes that remove organic pollution from wastewater. In this study, a selective method for the removal of crystal violet (CV) from aqueous solutions using nanocomposite of nickel oxide/zinc oxide nanoparticles (NiO/ZnO) supported on kaolinite photocatalyst was investigated. The raw kaolinite, bare NiO, bare ZnO and nanocomposite samples were characterized by the XRD, TEM, SEM-EDX, XPS and FTIR techniques. The photocatalytic performances of kaolinite-NiOZnO (K-NiO/ZnO) nanocomposite and bare samples were also investigated and comparatively evaluated by the photodegradation of CV (cationic dye) dye under visible light irradiation. The effects of various parameters such as the dosage of photocatalysis, contact time, and initial dye concentration on the rate of removal of dye were investigated and optimized. The kinetics of decolorization by samples can be well described by the pseudo-first-order model. Finally, it can be used in advanced oxidative processes for the degradation of organic pollutants.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2023Kaolin Yüzeyine Dekore Edilmiş Bakır Katkılı Çinko Oksit Nanokompoziti Kullanılarak Reaktif Mavi 21 Tekstil Boyar Maddesinin Adsorpsiyonu, Kinetiği ve Termodinamiği
Caglar, Bulent; Güner, Eda Keles; Doğan, Bilge; Özdemir, Agah Oktay
Bu çalışmanın amacı; tekstil endüstrisinde yaygın olarak kullanılan bir boyarmadde olan Reaktif Mavi 21 (RM21)’in atık sulardan adsorpsiyon yöntemiyle uzaklaştırılmasında kaolin yüzeyine dekore edilmiş bakır katkılı çinko oksit nanokompozitinin adsorban olarak kullanılabilirliğinin araştırılmasıdır. Adsorpsiyon üzerine, başlangıç RM21 konsantrasyonu, adsorban miktarı, sıcaklık ve denge süresi gibi çeşitli deneysel parametrelerin etkileri incelenmiştir. Adsorpsiyon hızının ikinci mertebeden hız ifadesine uyduğu ve kaolin yüzeyine dekore edilmiş bakır katkılı çinko oksit nanokompozitinin RM21 üzerine adsorpsiyonunun Redlich-Peterson izoterm modeliyle uyum sağladığı görülmüştür. Bu çalışmanın sonuçları, RM21’nin sulu çözeltilerden uzaklaştırılmasında kaolin yüzeyine dekore edilmiş bakır katkılı çinko oksit nanokompozitinin etkili bir adsorban olarak kullanılabileceğini göstermiştir.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2022Kil Esaslı Bütünüyle-Katı-Hal Kompozit Kurşun (II)-Seçici Potansiyometrik Elektrot
Caglar, Bulent; Topcu, Cihan; Güner, Eda Keles; Ozdokur, Kemal Volkan; Cubuk, Osman; Çoldur, Fatih; Doğan, Bilge; Özdemir, Agah Oktay
Bentonit kili XRD, FTIR ve SEM-EDX teknikleriyle karakterize edildi. Karakterize edilen kil bütünüyle katı hal kompozit potansiyometrik elektrot yapımında iyonofor madde olarak kullanılmış ve kilin potansiyometrik uygulaması gerçekleştirilmiştir. Elektrodun Pb2+ iyonuna karşı, diğer yaygın inorganik katyonlarla karşılaştırıldığında oldukça duyarlı ve seçici potansiyometrik bir cevap sergilediği gözlemlenmiştir. Membran optimizasyon çalışmaları neticesinde en iyi potansiyometrik performans özellikleri sergileyen bileşimin kütlece %65.0 grafit, %5.0 çok duvarlı karbon nanotüp, %20.0 iyonofor (bentonit) ve %10.0 parafin yağı olduğu belirlenmiştir. Pb2+ seçici kompozit elektrodun 1.0×10-5 ˗ 1.0×10-1 M konsantrasyon aralığında doğrusal cevap sergilediği, doğrusal çalışma aralığında standart Pb2+ çözeltilerine karşı her 10 katlık konsantrasyon değişiminde ortalama 31 mV potansiyel fark sergilediği gözlenmiştir. Elektrodun tayin sınırı 9.0×10-6 M olarak hesaplanmıştır. Elektrodun cevap zamanının oldukça kısa olduğu (~5 s) potansiyometrik cevabın ve tekrarlanabilirliğinin de oldukça yüksek olduğu ortaya konmuştur.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2022TiO2 Nanoparçacık Kaplı Pamuklu Kumaşın Fotokatalitik ve Antibakteriyel Özelliklerinin İncelenmesi
Kuzucu, Mehmet; Caglar, Bulent; Güner, Eda Keles; Doğan, Bilge; Özdemir, Agah Oktay
Bu çalışmada, fotokatalitik ve antibakteriyel özelliklere sahip, TiCl4'ün hidroliziyle sentezlenen farklı miktarlarda TiO2 nanoparçacıklar ile yüzey modifiye edilmiş pamuklu kumaşlar hazırlandı. Hazırlanan bu TiO2 nanoparçacıkları kaplı pamuklu kumaşların fotokatalitik aktiviteleri UVA ışınları altında Kristal Viyolet (KV) boyar maddesinin bozunmasında incelendi. KV’nin, TiO2 nanoparçacıkları kaplı pamuklu kumaşlar üzerindeki fotokatalitik bozunması için en uygun şartlar 0,625 mgL-1 başlangıç KV konsantrasyonu ve 57 mgL-1 TiO2 nanoparçacık yükleme miktarı olarak belirlendi. Bu en uygun şartlar altında, ilgili fotokatalizör varlığında 40 dakika içerisinde UVA ışınları altında KV’nin % 89,31’inin bozunmaya uğradığı tespit edildi ve bozunma reaksiyonunun birinci dereceden kinetiği takip ettiği belirlendi. Reaktif tür deneyleri, hidroksil radikallerinin diğer radikal türlere nispeten daha önemli bir rol oynadığını ortaya çıkardı ve elde edilen bu verilere göre olası bozunma mekanizması önerildi. Ayrıca TiO2 kaplanmış pamuklu kumaşların antibakteriyel aktivitesinin incelenmesi için disk difüzyon metodu kullanıldı. Antibakteriyel aktivite tayininde Gram pozitif bakteri olarak Staphylococcus aureus (ATCC 6538), Gram negatif bakteri olarak Escherichia coli (ATCC 25922) üzerinde denemeler gerçekleştirildi. Disk difüzyon deneyi sonuçlarına göre; 38 ve 57 mgL-1 konsantrasyonlarında TiO2 ile kaplanmış pamuklu kumaşlarda, antibiyotik referansların oluşturduğu inhibisyon zonu çapına kıyasla relatif olarak E. coli’ye karşı sırasıyla % 40,9 ve % 60,2 oranlarında antibakteriyel etki görülmüştür.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2022Facile synthesis of TiO2-coated cotton fabric and its versatile applications in photocatalysis, pH sensor and antibacterial activities
Özdemir, Agah Oktay; Caglar, Bulent; Çubuk, Osman; Coldur, Fatih; Kuzucu, Mehmet; Guner, Eda Keles; Doğan, Bilge; Caglar, Sema; Özdokur, Kemal Volkan
TiO2 nanoparticles-coated cotton fabric was readily prepared by the hydrolysis of TiCl4 solution over cotton fabric and characterized various techniques in comparison with pristine cotton fabric. Initially, the photocatalytic application of the obtained fabric was carried out by using it as a catalyst for the photodegradation of rhodamine B. A higher degradation ratio for rhodamine B in the presence of TiO2-coated cotton fabric as photocatalyst was observed under visible light compared to the one performed under UVA. The reactive species trapping experiments revealed that the superoxide radicals played a major role than other radical species and two different degradation mechanisms were proposed according the trapping results. Subsequently, considering that the fabricated TiO2-coated cotton fabric is a very suitable sensor material for the development of a wearable flexible pH sensor, a potentiometric solid state pH sensor prototype was constructed and tested for pH measurements. The proposed prototype exhibited a linear potentiometric response in the pH range from 2.0 to 9.0 with a slope of −23.9 mV/decade. The pH accuracies (as relative error %) calculated for the current electrode with respect to the commercial electrode in the studied buffer solutions were ranged between −1.8% and 1.9%. The presently proposed pH electrode allowed pH measurements highly coherent with commercially available pH electrode. Finally, the antibacterial activity of the TiO2 nanoparticles was evaluated by minimum bactericidal concentration (MBC), minimum inhibitory concentration (MIC) testing and also antibacterial property of the TiO2 nanoparticles-coated cotton fabric was demonstrated by GB/T 20944.3–2008 method using Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 25922) as representative strains of Gram-positive and Gram-negative bacteria, respectively. This study would be indicative to design of nano metal oxide-coated cotton fabrics in the application of photocatalyst, pH sensor and antibacterial agent against bacteria.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2021Bi2S3 nanorods decorated on bentonite nanocomposite for enhanced visible-light-driven photocatalytic performance towards degradation of organic dyes
Caglar, Bulent; Guner, Eda Keles; Ersoy, Selin; Caglar, Sema; Özdemir, Agah Oktay; Özdokur, Kemal Volkan; Doğan, Bilge; İçer, Fatih; Çırak, Çağrı
In this study, we prepared bentonite-Bi2S3 nanocomposite via decoration of Bi2S3 nanorods on bentonite for the first time to enhance the photocatalytic performance of Bi2S3 nanorods under visible light irradiation. XRD, TEM, SEM-EDX, XPS, UV-DRS, PL, electrochemical impedance spectroscopy, chronoamperometry, zeta potential, and BET techniques were used to compare analysis of structural, morphological, optical, electrochemical and textural properties of raw bentonite, bare Bi2S3 nanorods and bentonite-Bi2S3 nanocomposite. The photocatalytic performances of bentonite-Bi2S3 nanocomposite and bare samples were also investigated and comparatively evaluated by photodegradations of crystal violet and rhodamine B dyes under visible light irradiation. The photocatalytic degradation efficiencies of fabricated bentonite-Bi2S3 nanocomposite for crystal violet and rhodamine B were determined as 100% and 85% after the periods of 30 min and 90 min, respectively, which were more superior compared with those of bare Bi2S3 nanorods. The enhanced photodegradation activity of bentonite-Bi2S3 nanocomposite was assigned to the good visible light absorption ability, enlarged surface area, increased adsorption capability and decreased aggregation of Bi2S3 nanorods with the inclusion of bentonite platform as well as suppressed hole-electron recombination process due to electrostatic interaction between negatively charged bentonite surface and positively charged holes. The reactive species trapping revealed that hydroxyl radicals played a major role on the photodegradation and a plausible mechanism for photodegradation of dye molecules on bentonite-Bi2S3 nanocomposite was suggested. The photodegradation of dyes was found to follow the pseudo-first-order kinetic model. The prepared photocatalyst exhibited good reusability and stability after 4 cycles.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021A novel amperometric H2O2 biosensor constructed by cress peroxidase entrapped on BiFeO3 nanoparticles
Caglar, Bulent; İçer, Fatih; Özdokur, Kemal Volkan; Caglar, Sema; Özdemir, Agah Oktay; Guner, Eda Keles; Beşer, Burcu Meryem; Altay, Ahmet; Çırak, Çağrı; Doğan, Bilge
Herein, we synthesized ferromagnetic BiFeO3 nanoparticles with sizes of 20–60 nm and rhombohedral distorted perovskite structure without any co-formed impurity phases by sol-gel method. Structural, morphological, magnetic, electronic and textural properties of BiFeO3 nanoparticles were characterized by using XRD, SEM-EDX, TEM, FTIR, XPS, VSM, UV-DRS, PL and BET techniques. The peroxidase was isolated from the Cress (Lepidium sativum) and purified by using precipitation of ammonium sulfate and chromatographic techniques; gel filtration and ion exchange chromatography which is showed wide range of thermal stability, maximum activity in the acidic environment and close to the body temperature. Afterwards, a novel amperometric biosensor based on Cress peroxidase entrapped on BiFeO3 nanoparticles modified carbon paste electrode was prepared for the first time to sensitive detection of H2O2. The prepared H2O2 biosensor was operated with the aid of choro-amperometry technique by applying −0.8 V vs Ag/AgCl electrode. The developed biosensor exhibited a linear response towards to H2O2 in the concentration range of 2.0 10−7 to 1.0 10−5 M under the optimal conditions and limit of detection and quantification were estimated as 7.0 10−8 M (2.7 μg L−1) and 2.0 10−7 M (8.7 μg L−1), respectively. The repeatability of the electrode was calculated as 19.2 for 2.0 10−7 M (N = 7) and the accuracy was 81.2% for this concentration. In addition, the H2O2 biosensor exhibited excellent stability up to ten days. Finally, the sensor developed was used for the analysis of H2O2 in milk samples and satisfactory recoveries were obtained under the operating conditions.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2021Application of BiFeO3 and Au/BiFeO3 decorated kaolinite nanocomposites as efficient photocatalyst for degradation of dye and electrocatalyst for oxygen reduction reaction
Caglar, Bulent; Guner, Eda Keles; Özdokur, Kemal Volkan; Özdemir, Agah Oktay; İçer, Fatih; Caglar, Sema; Doğan, Bilge; Beşer, Burcu Meryem; Çırak, Çağrı; Tabak, Ahmet
To improve the photocatalytic performance and solve the aggregation problem of BiFeO3 nanoparticles, kaolinite-BiFeO3 photocatalyst was successfully prepared for the first time by decoration of ferromagnetic BiFeO3 nanoparticles onto kaolinite surface. Comparative characteristics of kaolinite, bare BiFeO3 and kaolinite-BiFeO3 photocatalyst were investigated in detail by XRD, TEM, SEM-EDX, XPS, FTIR, VSM, UV-DRS, PL, zeta potential and BET techniques. The photocatalytic activities of the samples were also evaluated by photodegradation of rhodamine B as a model reaction under different irradiations like UVA, visible and sunlight. The kaolinite-BiFeO3 exhibited more superior photocatalytic activity as compared with other samples, which is best fitted to pseudo-first-order kinetic. The reactive species trapping experiments indicated that photogenerated-holes play major roles in the degradation process whereas superoxide radicals possess a secondary effect. Enhanced photocatalytic activity of kaolinite-BiFeO3 is attributed to its kaolinite platform that reduces the recombination opportunities of the photogenerated holes and electrons as well as increases the surface area, decreases the particle size and aggregation of nanoparticles. In addition, we also designed a novel electrocatalytic platform based on gold nanoparticles loaded on kaolinite-BiFeO3 modified carbon paste electrode surface for the examination of electrocatalytic activity for oxygen reduction reaction in alkaline medium. Electrochemical characterizations of the Au/BiFeO3/kaolinite modified carbon paste electrode and other bare surfaces were comparatively carried out with the aid of cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Au/BiFeO3/kaolinite modified carbon paste electrode exhibited 15-fold current enhancement together with 100 mV anodic potential shift compared with bare carbon paste electrode.
RDL Kalıcı Kaydıİncele