9 results on '"CHEMICAL reduction"'
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2. ENTEGRE BİR TEKSTİL İŞLETMESİNDE KİMYASAL AZALTIMI VE KİMYASAL DEĞİŞİMİ UYGULAMASI.
- Author
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ÖZTÜRK, Emrah
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POLLUTION prevention ,PAYBACK periods ,CHEMICAL reduction ,FACILITY management ,TEXTILE industry ,NATURAL dyes & dyeing ,MICROPOLLUTANTS - Abstract
Copyright of SDU Journal of Engineering Sciences & Design / Mühendislik Bilimleri ve Tasarım Dergisi is the property of Journal of Engineering Sciences & Design and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
- Full Text
- View/download PDF
3. Synthesis of active platinum particles on the activated carbon with sodium borhydride as reduction agent
- Author
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OKUR, Osman
- Subjects
Pt particle ,chemical reduction ,fuel cell catalyst ,Pt parçacık ,kimyasal indirgeme ,yakıt pili katalizör ,Basic Sciences ,Temel Bilimler - Abstract
Aktif karbon yüzeyinde platin nanopartiküller, hekzakloroplatinik asidin (H2PtCl6) farklı indirgenlerle kimyasal indirgenmesiyle elde edilmiştir. İndirgeyici ajan olarak sodyum borhidrür, formik asit ve formaldehit seçilmiştir. Bu çalışmada platin parçacıklarının aktif karbon yüzeyindeki dağılımı ve yapısı üzerinde indirgeyici ajan seçiminin etkileri incelenmiştir. Elde edilen ürünlerin morfolojisi ve mikro yapısı taramalı elektron mikroskobu (SEM), faz karakterizasyonu X ışını kırınım spektrometre (XRD) ve yüzey alanı ile gözenek boyut dağılımları azot adsorpsiyon izoterminden BET yöntemi ile hesaplanarak belirlenmiştir. Elde edilen sonuçlar, indirgeyici ajan olarak sodyum borhidrürün kullanımının aktif karbon yüzeyinde homojen platin nanoparçacıklarının eldesi için optimum koşullar sunduğunu göstermiştir., Platinum nanoparticles on the activated carbon surface were obtained by chemical reduction of hexachloroplatinic acid (H2PtCl6) with different reducing agents. Sodium borohydride, formic acid and formaldehyde were chosen as reducing agents. In this study, the effects of the reducing agent on the uniform distribution and structure of platinum particles on activated carbon were investigated. The morphology and microstructure of the obtained products were characterized by SEM, phase characterization by XRD and surface area and pore distributions by BET method. The obtained results showed that the use of sodium borohydride as a reducing agent provides optimum conditions for obtaining homogeneous platinum nanoparticles on the activated carbon surface.
- Published
- 2022
4. Lityum iyon piller için kalay (II) oksit kompozit anot elektrotlarının üretimi ve karakterizasyonu.
- Author
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Güler, Mehmet Oğuz
- Abstract
In this study, the core component of the composite, tin (II) oxide powders synthesized through a facile chemical reduction methods for Li-ion batteries. As the shell structure, surfaces of the as-synthesized tin (II) oxide particles were coated with carbon through microwave assisted carburization process. The surface morphologies and phase components of the as-synthesized tin (II) oxide/carbon composites were investigated via scanning electron microscopy and X-ray diffraction methods, respectively. CR2016 type coin cells were prepared by using tin (II) oxide/carbon composite powders and electrochemical tests were performed at room temperature via 8-channel MTI BST8‒MA electrochemical test station between 10 mV and 2.5 V potential range by applying fixed 1 C state of charge conditions. The results have shown that tin (II) oxide/carbon composite structure have significantly improved the specific capacities to 396 mAh g-1 after 100 cycles. sea [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
5. ENANTİYOMERİK OLARAK SAF SEKONDER ALKOLLERİN ÜRETİMİNDE BİTKİ BİYOKATALİZÖRLERİ KULLANIMI.
- Author
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KAZICI, Hilal Çelik and MEHMETOĞLU, Ülkü
- Subjects
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BIOCATALYSIS , *ENANTIOMERS , *CHEMICAL reduction , *ACETOPHENONE , *ALCOHOL dehydrogenase , *REACTION time , *CARBONYL group , *EDIBLE plants - Abstract
In this study, enantiomerically pure (S)-1-Phenylethanol was produced with bioreduction of acetophenone that the precursor of many pharmacological product. Derivatives of (S)-1-Phenylethanol (secondary alcohol) is used as the active ingredient of drug of anti alzheimer. Production of (S)-1-Phenylethanol was conducted with the asymmetric reduction reaction of acetophenone that biocatalyst for there action is enzyme of alcohol dehydrogenase (ADH). In this study, a variety of fruits and vegetables were used as source of enzyme (ADH) for reduction of the carbonyl group and ADH enzyme activities were determined of different plants (carrots, potatoes, grapes, radishes) for selection of suitable plant which it has the highest intra cellular enzyme activity. At the end of this election carrot has been considered as a biocatalyst which has highest ADH activity. The effects of size of biyocatalyst, source of enzyme, substrate concentration, temperature, reaction time, pH of there action and the amount of biocatalyst have been investigated on the production of (S)-1-Phenylethanol. It was found that ADH enzyme in fresh carrots catalysed the bioselective asymmetric reduction reactions at high conversion and high enantioselectively (>%99 ee and 92% c), under the conditions of 2mM substrate concentration, 200 g/L biocatalyst concentration, 1,52 mm biyocatalyst size, reaction temperature 33 °C, pH=7 and 150 rpm agitation speed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
6. İndirgemecilik Açısından Kimya Öğretiminde Makro ve Mikro Bilgi Seviyeleri.
- Author
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SARITAŞ, Davut and TUFAN, Yüksel
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CHEMICAL reduction ,PHILOSOPHY of chemistry ,CHEMISTRY education ,PERSPECTIVE (Philosophy) ,THEORY of knowledge - Abstract
Copyright of Gazi University Journal of Gazi Educational Faculty (GUJGEF) is the property of Gazi University Journal of Gazi Educational Faculty (GUJGEF) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2013
7. The preparation and characterization of cafestol loaded cuo nanoparticles
- Author
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Erdokur, Özge Nur, Yıldırım, Yeliz, Fen Bilimleri Enstitüsü, and Kimya Anabilim Dalı
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Chitosan ,Kafestol ,CuO Nanoparticles ,Cafestol ,CuO Nanopartikülleri ,Chemical Reduction ,Biochemistry ,Kimya ,Chemistry ,Kimyasal İndirgenme ,Biyokimya ,Kitosan ,Biyoteknoloji ,Biotechnology - Abstract
Cancer, which is one of the most common diseases of our time, is known as uncontrolled cell division and proliferation. The chemical agents found in the structure of coffee have chemotherapeutic effect against cancer. The nanoparticle systems designed with specific components show antibacterial, antifungal and anti-carcinogenic properties. Among the various nanoparticle systems, the transition group metal oxide nanoparticles such as Iron (III) oxide, Zinc oxide and Copper (II) oxide are recorded in the literature, which has anticancer properties. In this thesis, the synthesis of Cafestol loaded CuO nanoparticles was aimed. CuO nanoparticles were synthesized by chemical reduction method and 60-90 nm CuO nanoparticles were obtained. Dimension optimization was performed by using various parameters such as temperature, reaction time and reducing reactor quantity. The optimized CuO nanoparticles were coated with chitosan, which is a biodegradable, natural polymer, and the cafestol was ligated. Chemical structure analyzes of the molecules were investigated with Fourier Transform Infrared (FTIR), size analyzes were performed by Malvern Zeta Sizer and Scanning Electron Microscope (SEM) methods and their thermal properties were examined with Thermogravimetry Analysis (TGA) and Differential Scanning Calorimeter (DSC) devices., Günümüzün en yaygın hastalıklarından biri olan kanser kontrolsüz hücre bölünmesi ve çoğalması olarak bilinmektedir. Kahvenin yapısında bulunan kimyasal ajanlar kafestol ve kahveol bileşiklerinin kansere karşı kemoterapik etkiye sahip oldukları literatürde bildirilmiştir. Spesifik bileşenlerle diyazn edilen nanopartikül sistemler antibakterial, antifingal ve anti-kanserojen özellikler göstermektedir. Çeşitli nanopartikül sistemleri arasında Demir (III) oksit, Çinko oksit ve Bakır (II) oksit gibi geçiş grubu metal oksit nanopartiküllerinin antikanser özellik gösterdiği literatürde kayıtlı bulunmaktadır. Bu tezde, Kafestol yüklü CuO nanopartikülerinin sentezi amaçlanmaktadır. CuO nanopartiküllerinin kimyasal indirgenme methodu ile sentezi gerçekleştirilmiştir. Nanopartikül boyutunun optimizasyonu için, reaksiyon sıcaklığı, reaksiyon süresi ve indirgeyici reaktif miktarı gibi çeşitli parametreler incelenerek, 60-90 nm boyutlarında CuO nanopartikülleri elde edilmiştir. Optimizasyonu sağlanan CuO nanopartikülleri, biyobozunur, doğal bir polimer olan kitosan ile kaplanmış ve kafestol bağlanmıştır. Moleküllerin kimyasal yapı analizleri Fourier Transform Infrared (FTIR) cihazıyla, boyut analizleri Malvern Zeta Sizer ve Scanning Electron Microscope (SEM) yöntemleriyle, termal özelllikleri Thermogravimeti Analysis (TGA) ve Differential Scanning Calorimeter (DSC) cihazlarıyla incelenmiştir.
- Published
- 2019
8. Cob nano tozu ve filmin elektrot performansları ve şarj/deşarj mekanizmaları
- Author
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Küçükdeveci, Nilüfer, Anık, Mustafa, TR245375, and ESOGÜ, Mühendislik Fakültesi, Metalurji ve Malzeme Mühendisliği
- Subjects
Mechanical Alloying ,CoB Powder and Films ,Electroless Plating ,Mekanik Alaşımlama ,Charge/Discharge ,Kimyasal Çöktürme ,CoB Toz ve Film ,Hydrogen Adsorption ,Hidrojen Adsorbsiyonu ,Akımsız Kaplama ,Chemical Reduction ,Şarj/Deşarj - Abstract
Bu çalışmada nikel esaslı şarj edilebilir pillerde negatif elektrot olarak kullanım potansiyellerini görmek amacıyla CoB alaşımları toz ve film halinde sentezlenmiştir. CoB alaşım tozları hem mekanik alaşımlama hem de kimyasal çöktürme yöntemiyle, CoB film ise akımsız kaplama yöntemiyle üretilmiştir. CoB elektrotların şarj/deşarj döngü karakteristikleri ve ısıl işlemin bu karakteristiklere etkisi araştırılmıştır. Amorf/nanokristal CoB tozunun sınırlı bir hidrojen depolama kapasitesinin olduğu kristalize olan CoB tozunun ise hidrojen adsorbsiyon yeteneğinin olmadığı gözlemlenmiştir. CoB alaşımında ilk deşarj sırasında 6M KOH elektrolit çözelti içerisinde bor bileşeninin büyük bir kısmı çözünmüştür. Borun çözelti içerisinde seçici olarak çözünmesinden sonra amorf/nanokristal CoB alaşım tozlarının da hidrojen adsorbe etme yeteneği ortadan kalkmıştır. CoB alaşımlarının ilk deşarj kapasitesi borun bu süreçte yükseltgenmesi nedeniyle yüksek bir değere ulaşmıştır. İlk şarj/deşarj’dan sonra CoB alaşım tozlarının tüm şarj/deşarj süreçleri tersinir olarak kobaltın yükseltgenme/indirgenme reaksiyonlarınca kontrol edildiği gözlemlenmiştir. Amorf/nanokristal ve kristalize CoB filmlerinde hidrojen depolama kapasitesinin sınırlı olduğu gözlemlenmiştir. Deşarj süreci boyunca CoB film yüzeyinde Co(OH)2 ve CoOOH bileşikleri oluşmuştur. CoB filmlerinin aktifleştirilmesini takiben gerçekleşen şarj/deşarj sürecine büyük ölçüde kobaltın tersinir yükseltgenme/indirgenme reaksiyonunun baskın etkisi görülmüştür. CoB filmlerinin lityum iyon pillerinin kullanımına yönelik yeterli elektrot performansının olmadığı tespit edilmiştir. CoB alaşımlarının hidrojen depolama konusunda literatürde mevcut çelişkili raporlar bu çalışmada ortaya konulan şarj/deşarj mekanizması ile büyük ölçüde aydınlatılmıştır. In this thesis, CoB powder alloys and films were synthesized in order to investigate the potential usage of them as negative electrodes in nickel based rechargeable batteries. CoB powder alloys were synthesized by both mechanical alloying and chemical reduction methods, CoB film was obtained by electroless coating technique. Charge/discharge cyclic characteristics of CoB electrodes and the effect of heat treatment on these characteristics were investigated. It was observed that the amorphous/nanocrystalline CoB powder had a very limited hydrogen storage capacity and the crystallized CoB had no hydrogen adsorption ability at all. Big portion of boron in CoB alloy dissolved in 6 M KOH electrolyte solution during initial discharge. Amorphous/nanocrystalline CoB alloy powder also lost its hydrogen storage ability after selective dissolution of boron in the solution. CoB alloy exhibited a significant initial discharge capacity due to oxidation of boron. After the first charge/discharge cycle the charge/discharge processes of CoB alloy powders were controlled totally by the reversible cobalt oxidation/reduction reactions. It was observed that all amorphous/nanocrystalline and cyrstalline CoB films had a very limited hydrogen storage capacity. Co(OH)2 and CoOOH compounds formed on the electrode surface during discharge process. After the activation of CoB film electrodes the charge/discharge process was mainly controlled by oxidation/reduction reactions of cobalt. It was observed that CoB films have no sufficient electrode performance to be used in lithium ion batteries. The developed charge/discharge mechanism in this study made important contributions to the contradictive reports on the electrode performance of CoB in the literature.
- Published
- 2015
9. Grafen türevlerin sentezi ve Cu(II) iyonlarının elektrokimyasal tayininde kullanılması
- Author
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İncebay, Hilal, Yazıcıgil, Zafer, Kimya Anabilim Dalı, and Enstitüler, Fen Bilimleri Enstitüsü, Kimya Ana Bilim Dalı
- Subjects
Grafen oksit ,Chemistry ,Metal sensör ,Kimyasal indirgeme ,İndirgenmiş grafen oksit ,Reduced graphene oxide ,Metal sensor ,Chemical reduction ,Kimya ,Cu(II) tayini ,Cu(II) determination ,Graphene oxide - Abstract
Bu tez çalışmasında Hummers metodu ile karbon nanoyapılardan grafen oksit ve indirgenmiş grafen oksit sentezlenmiş, sentezlenen nanoyapılar Fourier dönüşümlü infrared spektroskopisi, X-ışınları kırınım spektroskopisi, taramalı elektron mikroskobu ve Termogravimetri/difeansiyel termal analiz ile karakterize edilmiştir. Grafen oksit (GO) ve indirgenmiş grafen oksitin (rGO) suda hazırlanan çözeltilerinin camsı karbon elektrot yüzeyine fiziksel immobilizasyonu ile sırasıyla grafen oksit modifiye camsı karbon (GO/GC) elektrot ve indirgenmiş grafen oksit modifiye camsı karbon (rGO/GC) elektrot olmak üzere iki farklı yüzey elde edilmiştir. Hazırlanan modifiye elektrot yüzeyleri; redoks problar varlığında dönüşümlü voltametri ve elektrokimyasal impedans spektroskopisi teknikleri ile elektrokimyasal olarak ve taramalı elektron mikroskobu ile mikroskobik olarak karakterize edilmiş, elde edilen karakterizasyon sonuçları yalın GC elektrot yüzeyine ait verilerle karşılaştırılmıştır. Hazırlanan bu yüzeylerin farklı tuz yapılarındaki (CuCI2, Cu(NO3)2, CuSO4) Cu(II) iyonlarına gösterdiği hassasiyet diferansiyel puls voltametri, kare dalga voltametri ve açık devre potansiyeli teknikleriyle, yüzey morfolojisi ise taramalı elektron mikroskobu ile incelenmiş ve elektrokimyasal olarak Cu(II) iyonunun tayinine anyon köklerinin etkileri tartışılmıştır. Modifiye yüzeylerin kararlılık ve tekrarlanabilirlik çalışmalarının yanısıra Zn(II), Pb(II), Cd(II), Fe(III) ve Mn(II) gibi farklı ağır metallerin Cu(II) iyonunun elektrokimyasal tayinindeki girişim etkileri de araştırılmıştır., In this thesis, graphene oxideand reduction graphene oxide nanoparticles synthesized by Hummers method and characterizated by Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy, thermogravimetric analysis. Then solution of graphene oxide (GO) and reduced graphene oxide (rGO) solutions by physical immobilization on the glassy carbon electrode surface were modified were obtained two different surfaces (GO/GC and rGO/GC). The modified electrodes prepared by this way and bare GC characterizated by cyclic voltammetry, electrochemical impedans spectroscopy, scanning electron microscopy. Then application of graphene oxide-modified glassy carbon electrode,(GO/GC) for the electrochemical determination of copper(II) using different copper salts such as CuSO4.5H2O, Cu(NO3)2.3H2O and CuCI2 performed by differential pulse voltametry, square wave voltametry, open circuit potential. The GO/GC electrode was found to be suitable for selective determination of Cu(II) in the solutions containing the mixture of heavy metal ions (Zn(II), Pb(II), Cd(II), Fe(III) ve Mn(II))and showed high stability and reproducibility. GO/GC surface in optimum conditions treating with CuSO4.5H2O, Cu(NO3)2.3H2O and CuCI2 salts solution and then SEM images was measured 10 µm in size and radius of this ions in Cu(II)/GO/GC surfaces. Thus, in the GO/GC surface determination of copper made for the first time by comparing the different salts. When evaluated from the inorganic aspect, the results were found to be in harmony., Bu tez çalışması Selçuk Üniversitesi Bilimsel Araştırmalar Koordinatörlüğü tarafından 13201024 nolu proje ile desteklenmiştir.
- Published
- 2015
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