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• MakaleYalnız künye2025Scopus SJRQ1/r/bayburt/12636
  Eco-friendly reduction of graphene oxide using urea: An optimized approach for high-performance rGO

  Ucuncuoglu, Didar; Bektaş, Enes; Karakaş, İbrahim Hakkı; Amin Bhuiyan, Mohammad Ruhul; Korucu, Haluk

  The growing demand for environmentally friendly and cost-effective approaches has accelerated the development of sustainable methods for the synthesis of reduced graphene oxide (rGO). In this study, urea was utilized as a green reducing agent for rGO synthesis, offering an alternative to conventional toxic chemicals. The synthesized rGO was comprehensively characterized using FTIR, SEM-EDS, Raman spectroscopy, XRD, BET analysis, zeta potential, and conductivity measurements. These analyses revealed key functional, structural, and morphological properties, including surface functional groups, elemental composition, carbon-to-oxygen (C/O) ratio, particle size (PS), crystallite size (CS), specific surface area (SSA), zeta potential (ZP), thermal conductivity (TC), and electrical conductivity (EC). Process optimization was performed using the Taguchi L4(23) orthogonal array design across nine quality parameters. Under optimal conditions, notable enhancements were achieved: C/O ratio increased by 108%, ID/IG ratio by 164%, I2D/IG ratio by 26%, CS by 75%, and SSA by 134%, while PS was reduced by 37%. Furthermore, ZP and TC increased by 58% and 33%, respectively, whereas EC was reduced by 97%. These findings demonstrate the potential of urea as a sustainable and effective reducing agent in the production of high-performance rGO materials.

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  AtıfScopus3·WoS3·OpenAlex3

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• MakaleAçık Erişim2025Scopus SJRQ4/r/bayburt/11348
  Synergistic electromagnetic wave absorbing properties of NiFe2O4/MWCNT composites synthesized via microwave-assisted combustion method in Ku-band

  Johari, Mohd Hilmi; Ismail, Ismayadi; Azis, Rabaah Syahidah; Tim, Chan Kar; Nafis, Nur Biha Mohamed; Ertugrul, Mehmet; Karakaş, Ibrahim Hakki

  This study investigates the synthesis, microstructural characteristics, magnetic properties, and electromagnetic wave absorption performance of nickel ferrite (NiFe2O4) composites reinforced with multi-walled carbon nanotubes (MWCNTs) synthesized via the microwave-assisted combustion (MAC) method. X-ray diffraction (XRD) analysis confirmed the desired structure of NiFe2O4 and the successful integration of MWCNTs within the NiFe2O4 matrix. Field emission scanning electron microscopy (FESEM) analysis revealed the entanglement of MWCNTs and their significant impact on hindering particle growth, resulting in a finer particle structure. The reduction in average particle size from 1.317 µm for pure NiFe2O4 to 0.436 µm for NiFe2O4 with 2wt% MWCNT, representing approximately a 66.89% reduction, significantly demonstrates the effectiveness of MWCNTs in limiting particle growth and promoting a more refined particle structure. Magnetic property analyses showed a nuanced interplay between MWCNT concentration and composite behaviour, with the saturation magnetization (Ms) exhibiting substantial enhancement in the NiFe2O4/2wt%MWCNT composite, indicative of effective alignment of magnetic moments. However, a subsequent decrease in Ms at higher MWCNT concentrations (4wt% and 6wt%) suggested potential dilution effects and disruptions in magnetic interactions within the composite. Electromagnetic wave absorption investigations revealed NiFe2O4/4wt%MWCNT as a highly efficient absorber in the Ku-band, with superior impedance matching and a high attenuation constant. The reflection loss (RL) reached a maximum of –17.58 dB at 12.78 GHz, signifying absorption of more than 99% of the incident EM wave in the microwave range. The favourable impedance matching and high attenuation constant contributed to the superior performance of NiFe2O4/4wt%MWCNT compared to pure NiFe2O4 and MWCNT. These findings suggest the potential of NiFe2O4/MWCNT composites for applications in telecommunications, aerospace, and electronics, with opportunities for further optimization and investigation into long-term stability and durability under varying environmental conditions.

  AtıfScopus1·WoS2·OpenAlex1

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11246
  High-Performance Microwave-Absorbing Hemp Textile: Ni-Zn Ferrite and Multiwalled Carbon Nanotubes-Infused Nanocomposite for X-Band Electromagnetic Interference Shielding

  Teber, Pembe; Teber, Ahmet; Karakaş, İbrahim Hakkı

  This study aims to develop a flexible and sustainable electromagnetic (EM) wave-absorbing material by using hemp fabric as a substrate incorporated with multiwalled carbon nanotubes (MWCNTs) and magnetic Ni-Zn ferrite nanoparticles (NPs). In this context, the objective is to achieve effective EM attenuation across a wide frequency range using a green, lightweight composite to meet the rising demand for ecofriendly shielding in electronic and communication systems. Ni0.5Zn0.5Fe2O4 and MWCNT composite NPs are uniformly dispersed in a molten paraffin binder and impregnated into hemp fabrics. The magnetic NPs are synthesized via the microwave-assisted combustion method. The EM parameters of the resulting structure are determined in the X-band using experimental scattering data and the Nicholson–Ross–Weir method. Absorption performance is evaluated based on varying weight ratios of magnetic NPs and MWCNTs, with an emphasis on impedance matching. The results indicate that combining dielectric and magnetic components significantly enhances absorption. A maximum reflection loss of −72.42 dB and a 3.81 GHz bandwidth (covering over 90.71% of the X-band) are achieved at 10.08 GHz. Increasing Ni-Zn content shifts the resonance to higher frequencies. This sustainable, flexible composite shows strong potential for electromagnetic interference shielding, particularly in defense applications requiring radar invisibility.

  AtıfScopus1·WoS1·OpenAlex1

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• MakaleAçık Erişim2024Scopus SJRQ3/r/bayburt/11678
  InvestIgatIon of cytotoxIcIty and antIbacterIal effect of boron-contaInIng nano-hydroxyapatIte

  Aydın, Numan; Karaoğlanoğlu, Serpil; Süloğlu, Aysun Kılıç; İdil, Neslihan; Demir, Merve; Karakaş, İbrahim Hakkı

  Introduction: Different regenerative materials are used to protect and stimulate pulp tissue. Objectives: This in vitro study aimed to examine the cytotoxicity of different doses of boron-containing nano-hydroxyapatite (B-nHAp) and its antibacterial effect. Material and methods: B-nHAp was synthesized with microwave-assisted chemical precipitation method at different rates, such as 1%, 5%, and 10%. The extracts were prepared in separate tubes: 1%, 5%, 10% B-nHAp, and nHAp 50 mg/ml. Cytotoxicity test was performed on L929 mouse fibroblasts for 24 and 72 hours. Antibacterial analysis was performed with Streptococcus mutans bacteria using micro-dilution method. Cell viability values were evaluated with two-way analysis of variance (ANOVA) test (p < 0.05). Results: B-nHAp was successfully synthesized in XRD and SEM analyses. Nano-hydroxyapatite showed more cell viability than control group at 24 and 72 hours. All B-nHAp extracts demonstrated less cell viability at the end of 24 hrs. than control group. However, 1% B-nHAp cell viability decreased more in the B-nHAp group compared with the control group, while 5% and 10% B-nHAp showed high cell viability after 72 hours of incubation. B-nHAp demonstrated less antibacterial effect on Streptococcus mutans compared with nHAp. Conclusions: According to the results, the addition of boron to nano-hydroxyapatite does not make a significant contribution to increase the regenerative and antibacterial properties of the material.

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  AtıfScopus4·OpenAlex5

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• MakaleYalnız künye2023Scopus SJRQ3/r/bayburt/10868
  The effects of heat treatment temperatures on photocatalytic activity of cobalt ferrite nanoparticles synthesised by microwave-assisted combustion method

  Karakaş, Ibrahim Hakki; Karcioğlu Karakaş, Zeynep

  In this study, the effects on the photocatalytic activities of particles after heat treatment has been applied to cobalt ferrite nanoparticles produced by microwave-assisted combustion method were observed. The heat treatment applied to the samples was produced with only the microwave effect, at temperatures ranging from 300 to 1000°C. Thermogravimetric analysis was performed on the precursor sample in air atmosphere. During this analysis, the gases released up to 1200°C were identified with a Fourier-transform infrared (FTIR) spectrometer integrated into a thermogravimetric analysis system. Then, the cobalt ferrite nanoparticles produced with heat treatments applied at various temperatures were used as a photocatalyst to remove the dyestuff content in synthetic wastewaters prepared by using Astrazon Red GTL textile dye by photocatalytic oxidation, and their photocatalytic activities were compared. In these experiments, the operational parameters for photocatalysis processes were applied as 400 rpm for stirring speed, 50 mg/L for initial contaminant concentration, 0.5 g/L for catalyst dosage, 25°C for temperature, and 4400 μW/cm2 for light intensity. As a result of the experiments, it was observed that the crystal structure of the cobalt ferrite nanoparticles produced with the increase of the applied heat treatment temperature improved significantly. The obtained data show a strong relationship between the structural properties of materials and their photocatalytic activities. In addition, it was determined that the dyestuff in the solution was completely degraded in the experiments, and it was determined that all processes were compatible with the pseudo-first-order kinetic model.

  AtıfScopus4·WoS5·OpenAlex6

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• MakaleYalnız künye2022Scopus SJRQ2/r/bayburt/13201
  Photocatalytic activity of cobalt aluminate nanoparticles synthesized by microwave-assisted combustion method

  Karakaş, İbrahim Hakkı; Karcıoğlu Karakaş, Zeynep; Ertuğrul, Mehmet

  Cobalt aluminate is one of the most widely-used spinel aluminate types. It is known that various structural, magnetic and morphological properties of spinel ceramics can vary depending on the synthesis technique and the starting chemicals used. In this study, initially, heat treatment was applied to cobalt aluminate nanoparticles synthesized by the microwave-assisted combustion method and the effects of the applied heat treatment on the structural properties were investigated. Characterization studies showed that cobalt aluminate spinel pigments were successfully synthesized. The optimum heat treatment temperature was determined as 700 °C. Then, the synthesized cobalt aluminate nanoparticles were used as photocatalysts for dye removal by photocatalytic oxidation from a synthetic wastewater containing Astrazon red textile dye and their photocatalytic activity was investigated at different catalyst dosages. Moreover, the same particles were also produced by conventional combustion technique. Then, their photocatalytic activities were studied and the data were compared with the results obtained from the experiments made with the samples produced with microwave assisted combustion method under the same experimental conditions. The results show that cobalt aluminate nanoparticles synthesized by microwave assisted combustion exhibit a better photocatalytic activity. In experiments performed with samples produced via microwave-assisted combustion method, all dyestuff content in the solution containing 50 mg/L dye was completely removed under UV irradiation for approximately 60 min. It was determined that the catalyst dosage had an effect on the reaction rate and the reaction was found to be compatible with the pseudo first order kinetic model.

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  AtıfScopus12·WoS12·OpenAlex13

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• MakaleYalnız künye2021Scopus SJRQ1/r/bayburt/12135
  The effects of fuel type onto the structural, morphological, magnetic and photocatalytic properties of nanoparticles in the synthesis of cobalt ferrite nanoparticles with microwave assisted combustion method

  Karakas, İbrahim Hakkı

  In this experimental study, the synthesis of cobalt ferrite nanoparticles, one of the most important types of ferromagnetic spinel ferrite materials was realized by using a method known as microwave assisted combustion method. The effects of the substance used as fuel on the structural, morphological, magnetic and photocatalytic properties of synthesized nanoparticles were investigated. Firstly, samples were prepared using urea, glycine and citric acid as fuel and then the samples were comprehensively characterized by advanced analysis techniques such as XRD, FT-IR, TEM, SEM, VSM, BET. Moreover, the usability of the obtained nanoparticles in photocatalytic degradation process of Procion Yellow H-E3G textile dye as photocatalyst was investigated. The results obtained indicate that the fuel used is highly effective on various properties of the synthesized materials. From the experiments performed to evaluate the photocatalytic performances of the nanoparticles, it was observed that each of the three different fuel matters used for the synthesis of nanoparticles were highly effective on the photocatalytic degradation of the organic pollutant. Furthermore, almost all the dye content in solution was completely removed at the end of the experimental period which lasted for 90 min.

  AtıfScopus50·WoS44·OpenAlex51

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• MakaleAçık Erişim2019/r/bayburt/15064
  Mikrodalga Destekli Yakma Metoduyla Kalsiyum Aluminat (CaAl2O4) Spinel Seramiklerin Sentezi ve Karakterizasyonu

  Karakas, Ibrahim Hakki

  Bu deneysel çalışmada, spinel seramiklerin önemli bir türü olan kalsiyum aluminat (CaAl2O4) nanopartiküllerinbasit, hızlı ve etkili bir sentez tekniği olan mikrodalga destekli yakma metoduyla sentezlenebilirliği vekarakterizasyonu araştırılmıştır. Bu amaçla yakıt olarak üre kullanılarak CaAl2O4 nanopartiküller mikrodalgadestekli yakma metoduyla sentezlenmiştir. Elde edilen ürünler TGA, XRD, FT-IR, SEM ve TEM teknikleri ilekapsamlı bir şekilde analiz edilmiştir. Bu üründe yapılan XRD ve FT-IR analizleri uygulanan mikrodalgaetkisinin ürünlerin tam dönüşümünde tek başına yeterli olmadığı belirlenmiştir. Buna göre, elde edilennanopartiküllerin yapısal ve morfolojik özelliklerini iyileştirmek ve ürüne dönüşüm oranını arttırmak için 300°Cile 1000°C derece arasında değişen sıcaklıklarda ısıl işleme tabi tutulmuştur. 800°C ve üzerindeki sıcaklıklardauygulanan ısıl işlem sonrasında elde edilen partiküllerin tamamen kalsiyum aluminat nanopartikülleredönüştükleri belirlenmiştir.

  AtıfOpenAlex1

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• MakaleAçık Erişim2019Scopus SJRQ2/r/bayburt/13157
  Effective reduction of graphene oxide using sulfur dioxide-containing chemical compounds

  Korucu, H.; Şimşek, B.; Kocakerim, M.M.; Karakaş, I.H.

  The success of the graphene oxide reduction process depends on how similar the product is to pristine graphene. Sulfur oxide, which is a significant industrial waste gas, can be used in the reduction of graphene oxide. In this study, the graphene oxide reduction process was performed by using sulfur oxide with sodium tetraborate decahydrate, l-ascorbic acid, ammonium hydroxide, sodium hydroxide, lithium hydroxide, sodium borohydride and sodium thiosulfate. The carbon-to-oxygen atomic ratio and D-to-G peak ratio of the graphene oxide, which represent the degree of reduction, were 2.64–4 and 0.78–1.80 with the use of sulfur oxide, respectively. The sulfur oxide/sodium borohydride mixture increased the carbon-to-oxygen atomic ratio of the graphene oxide to 11.73, while improving the value of the D-to-G peak ratio at 3.14. The reduced graphene oxide with the highest specific heat capacity was obtained using sodium tetraborate decahydrate, with an improvement of 74.54% compared to graphene oxide. The results show that sulfur oxide, which is harmful to the environment and human health, can be utilized in an effective reduction process, together with other reducing chemicals, to obtain an industrially valuable material, such as reduced graphene oxide.

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  AtıfScopus15·WoS14·OpenAlex15

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• MakaleAçık Erişim2019Scopus SJRQ2/r/bayburt/12475
  Antimony removal from aqueous solutions using magnetic nickel ferrite (NiFe 2 O 4 ) nanoparticles

  Karcioğlu Karakaş, Zeynep; Boncukcuoğlu, Recep; Karakaş, İbrahim Hakkı

  In this study, magnetic nickel ferrite (NiFe 2 O 4 ) nanoparticles were synthesized via microwave assisted combustion method and these particles were used as adsorbent for antimony removal. The most effective parameters for the removal efficiency are adsorbent dosage and temperature, while the impact of pH is insignificant. In order to determine the most suitable kinetic model, the compatibility of pseudo-first order, pseudo-second order and the intraparticle diffusion model was compared and the most suitable kinetic model was determined to be pseudo-second-order. Langmuir and Freundlich isotherms were assessed and the most suitable isotherm was observed to be Freundlich model.

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  AtıfScopus6·WoS3·OpenAlex6

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