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Fenolik Bileşiklerin Katalitik Olarak İndirgenmesinde Kullanilmak Üzere Kitosan ve Titanyum Dioksit Destekli Plazmonik Katalizör Sentezi

dc.contributor.advisorYavuz Ersan, Hülya
dc.contributor.authorErdem, Gökçe
dc.date.accessioned2017-06-12T06:21:04Z
dc.date.available2017-06-12T06:21:04Z
dc.date.issued2017
dc.date.submitted2017-01-18
dc.identifier.urihttp://hdl.handle.net/11655/3481
dc.description.abstractThe purpose of this thes is is the fabrication and performance evaluation of new catalysts which enable the elimination of toxic pollutants such as 4 - Nitrophenol (4 - NP) by means of heterogeneous catalytic reduction in an aq ueous environment. Production of two different catalysts was achieved by the immobilization of the plasmonic gold nanoparticles (AuNP) into the chitosan and titanium dioxide support materials, respectively. The plasmonic catalytic activities of fabricated catalysts were evaluated within the reduction of 4 - Nitrophen ol in the presence of sodium borohydride (NaBH 4 ) as a reducin g agent. The effects of type of support material and size of nanoparticle as performance enhancing parameter, loading amount of nanoparticle, catalyst amount and initial 4 - Nitrophenol concentrati on as operational parameters are evaluated in batch fashion. In line with this purpose, firstly the support materials were synthesized. Chitosan microgel beads were obtained by the chemical modification of chitosan solution. The monodisperse chitosan micr ogel beads, 3 mm in size with the specific surface area of 1.3 m 2 /g, were synthesized by crosslinking reaction in which glutaraldehyde served as a cross - linker. Titanium dioxide (TiO 2 ) spheres as second support material, were obtained by one - step sol - gel m ethod. TiO 2 spheres in the size range of 0.7 - 1.2  m with the specific surface area 277.4 m 2 /g were synthesized along with the hydrolysis of titania precursor, titanium ii isopropoxide in a continuous medium including methanol and acetonitrile. TiO 2 spheres were derivatized with Aminopropyltriethoxysilane (APTES), that enables TiO 2 to adsorb gold atoms through the amine groups on its surface. In the next stage, the support materials were added into the solutions of gold nanoparticles that have been s ynthesized with Turkevich (12 nm) and Martin (3 nm) Methods, respectively. The bare, Turkevich AuNP decorated and Martin AuNP decorated support materials were characterized by energy - dispersive x - ray spectroscopy, scanning electron microscopy, transmission electron microscopy, x - ray diffaraction spectrophotometry and surface area analysis via nitrogen adsorption - desorption method. The gold nanoparticle decorated chitosan microgel beads and TiO 2 spheres were used in the reduction of 4 - Nitrophenol, individually. The decoration with Martin AuNPs with lower size resulted in a significant enhancement in the plasmonic catalytic reduction rate owing to the electron transfer characteristics of AuNPs wit h lower size. The complete reduction of 4 - Nitrophenol having initial concentration of 7.5 ppm was achieved within 12 minutes in the presence of 10 mg Martin AuNP decorated chitosan microgel beads as catalyst (%2.5 (%w/w) AuNP loading). On the other hand, t he complete reduction of 4 - Nitrophenol having initial concentration of 7.5 ppm was achieved within 60 seconds in the presence of 12.5 mg Martin AuNP decorated TiO 2 spheres as catalyst (%2 (%w/w) AuNP loading). The recovery and reusability studies, conducte d under the same experimental conditions, indicated that the catalysts are reusable for reduction of 4 - Nitrophenol. In the plasmonic catalytic reduction of 4 - Nitrophenol via Au/chitosan and Au/TiO 2 catalysts, higher catalytic activities were obtained when compared to the other treatment methods, introduced in literature, involving catalysts supported with similar forms of different materials or different forms of similar materials. In this thesis, for the first time, Au/chitosan catalyst in the microgel bea d form and Au/TiO 2 catalyst in sphere form having novel structures and sizes were synthesized via simple, cost - effective, energy and time saving and environmentally friendly methods. Moreover, this study introduces biodegradable, porous, low - cost, mechanic ally stable catalysts that are able to form strong interaction with metal nanoparticles to the catalytic applications in favor of high catalytic activitiestr_TR
dc.description.tableofcontentsTABLE OF CONTENTS Page ABSTRACT ................................ ................................ ................................ ........................... i ÖZET ................................ ................................ ................................ ................................ .... ii i ACKNOWLEDGEMENTS ................................ ................................ ................................ .. v TABLE OF CONTENTS ................................ ................................ ................................ ..... vi LIST OF TABLES ................................ ................................ ................................ ............... ix LIST OF FIGURES ................................ ................................ ................................ ............... x SYMBOLS AND ABBREVIATIONS ................................ ................................ .............. xiii 1. INTRODUCTION ................................ ................................ ................................ ......... 1 2. LITERATURE REVIEW ................................ ................................ .............................. 3 2.1. W astewater and Common Pollutants........................................................ 3 2.2. Nitrophenolic Compounds.................................................................... 6 2. 2.1. Properties and Sources of 4 - Nitrophenol ................................ ............................ 6 2 .2.2. Toxicological Profile of 4 - Nitrophenol ................................ ............................... 9 2.2.3 . Treatment Methods of 4 - Nitrophenol ................................ ................................ .. 9 2.3. Plasmon - Enhanced Heterogen eous Catalysis of 4 - Nitrophenol........................ 12 2.3.1. Properties and Synthesis of AuNPs as Plasmonic Catalyst .............................. 15 2.3.1.1. Turkevich Method ................................ ................................ ...................... 16 2.3.1.2. Martin Method ................................ ................................ ............................ 17 2.3.2. Properties and Synthesis of a Support Material ................................ ................ 18 2.3.2.1. Chitosan as a Support Material ................................ ................................ ... 20 2.3.2.2. Titanium Dioxide as a Support Material ................................ .................... 24 3. EXPERIMENTAL METHODS ................................ ................................ .................. 27 3.1. Plasmon - Enhance d Heterogeneous Catalyst Design.................................... 27 3.1.1. Synthesis of AuNPs as Promising Plasmonic Catalyst ................................ ..... 27 3.1.1.1. Materials ................................ ................................ ................................ ..... 27 3.1.1.2. Synt hesis of AuNP by Turkevich Method ................................ .................. 27 3.1.1.3. Synthesis of AuNP by Martin Method ................................ ....................... 27 vii 3.1.2 . Synthesis of AuNP Decorated Chitosan Microgel Beads ................................ . 28 3.1.2.1. Materials ................................ ................................ ................................ ..... 28 3.1.2.2. Synthesis of Bare Chitosan Microgel Beads as a Support Material ........... 28 3.1.2.3. Decoration of Chitosan Microgel Beads with Turkevich AuNP and Martin AuNP ................................ ................................ ................................ ....................... 29 3.1.3. Synthesis of AuNP Decorated Polydisperse Titanium Dioxide Spheres .......... 29 3.1.3.1. Materials ................................ ................................ ................................ ..... 29 3.1.3.2. Synthesis of Bare Titanium Dioxide Spheres Spheres as Support Material ................................ ................................ ................................ ................................ . 30 3.1.3.3. Derivatization of Titanium Dioxide Spheres with Aminopropyltriethoxysilane ................................ ................................ .................... 30 3.1.3.4. De coration of Titanium Dioxide Spheres with Turkevich AuNP and Martin AuNP ................................ ................................ ................................ ....................... 30 3.2. Characterization Studies..................................................................... 31 3.3. Plasmon - Enhanced Heterogen eous Catalysis of 4 - Nitrophenol........................ 33 3.3.1. Materials ................................ ................................ ................................ ............ 33 3.3.2. Reduction of 4 - Nitrophenol by the Turkevich AuNP and Martin AuNP Decorated Chitosan Microgel Beads ................................ ................................ ........... 34 3.3.3. Reduction of 4 - Nitrophenol by the Turkevich AuNP and Martin AuNP Decorated Titanium Dioxide Spheres ................................ ................................ ......... 35 3.3.4. Recovery and Reusability of Catalyst ................................ ............................... 36 4. RESULTS & DISCUSSION ................................ ................................ ....................... 38 4.1. Synthesis and Charact erization of Plasmonic Catalyst.................................. 38 4.1.1. Synthesis and Characterization of AuNPs Synthesized by Turkevich and Martin Methods ................................ ................................ ................................ ....................... 38 4.2. Synthesis and Characterization of Support Materials Decorated with T urkevich AuNPs and Martin AuNPs........................................................................ 39 4.2.1. Synthesis and Char acte rization of Bare and AuNP Decorated Chitosan Microgel Beads ................................ ................................ ................................ ............ 39 4.2.2. Synthesis and Char acterization of Bare and AuNP Decorated Titanium Dioxide Spheres ................................ ................................ ................................ ........................ 42 4.3. Plasmon - Enhanced Hetero geneous Catalytic Activity Runs........................... 45 4.3.1. Reduction Mechanism of 4 - Nitrophenol ................................ ........................... 45 viii 4.3.2. Plasmonic Catalysis of 4 - Nitrop henol in the Presence of AuNP Decorated Chitosan Microgel Beads ................................ ................................ ............................ 46 4.3.2.1. Effect of AuNP Size and Loading ................................ .............................. 47 4.3.2.2. Effect of Catalyst Amount ................................ ................................ .......... 49 4.3.2.3. Effect of Initial 4 - Nitrophenol Concentration ................................ ............ 50 4.3.2.4. Recovery and Reusability ................................ ................................ ........... 51 4.3.3. Plasmonic Catalysis of 4 - Nitrop henol in the Presence o f AuNP Decorated Titanium Dioxide Spheres ................................ ................................ ........................... 53 4.3.3.1. Effect of AuNP Size and Loading ................................ .............................. 54 4.3.3.2. Effect of Catalyst Amount ................................ ................................ .......... 55 4.3.3.3. Effect of Initial 4 - Nitrophenol Concentration ................................ ............ 56 4.3.3.4. Recovery and Reusability ................................ ................................ ........... 57 5. CONCLUSION ................................ ................................ ................................ ........... 60 REFERENCES............................................. ... ........................................ 3 CURRICULUM VITAE ................................ ................................ ................................ ..... 71tr_TR
dc.language.isoentr_TR
dc.publisherFen Bilimleri Enstitüsütr_TR
dc.rightsinfo:eu-repo/semantics/openAccesstr_TR
dc.subjectAtıksu Arıtımıtr_TR
dc.subjectWastewater treatmenttr_TR
dc.subject4 - Nitrophenol
dc.subjectPlasmonic Catalysis
dc.subjectGold Nanoparticle
dc.subjectChitosan Microgel Beads
dc.subjectTitanium Spheres
dc.subject4 - Nitrofenol
dc.subjectPlazmonik Katalizleme
dc.subjectAltın Nanopartikül
dc.subjectKitosan Mikrojel Tanecikler
dc.subjectTitanyum Küreler
dc.titleFenolik Bileşiklerin Katalitik Olarak İndirgenmesinde Kullanilmak Üzere Kitosan ve Titanyum Dioksit Destekli Plazmonik Katalizör Sentezitr_TR
dc.typeinfo:eu-repo/semantics/masterThesistr_TR
dc.description.ozetBu tez kapsamında, atık sularda sıklıkla rastlanan toksik fenolik bileşiklerden 4 - Nitrofenolün sulu ortamda katalitik indirgenme yoluyla giderimi için uygun 2 yeni heterojen plazmonik katalizör sisteminin geliştirilmesi ve bu si stemlerin katalitik performansı nın belirlenmesi amaçlanmıştır. Heterojen katalizörlerin üretiminin, plazmonik altın nanopartiküllerin (AuNP), son yıllarda önem kazanmış ve gelecek vaadeden kitosan ve titanyum dioksit destek maddelerine immobilizasyonu ile gerçekleştirilmesi hedeflenmiştir. Katalizörlerin katalitik aktiviteleri 4 - Nitrofenolün indirgeme ajanı olan NaBH 4 varlığında indirgenmesi sırasında değerlendirilmiştir. Bu deneylerde, destek madde - metal nanopartikül etkileşiminin, AuNP boyutunun, AuNP yük leme miktarının, katalizör miktarının ve başlangıç 4 - Nitrofenol başlangıç konsantrasyonun katalitik aktiviteye etkisi kesikli sistemde belirlenmiştir. Bu amaç doğrultusunda ilk olarak katalizör destek maddeleri üretilmiştir. Mikrojel formundaki kitosan tan ecikler, kitosan çözeltisinin kimyasal modifikasyonuyla meydana gelmiştir. Glutaraldehitin çapraz bağlayıcı olarak kullanıldığı çapraz bağlama işleminin sonucunda 3 mm çapında, eş boyutlu, 1.3 m 2 /g yüzey alanına sahip kitosan tanecikler elde edilmiştir. Di ğer bir katalizör destek maddesi olan TiO 2 küreler ise tek aşamalı sol - jel yöntemiyle üretilmiştir. Küreler, titanyum isopropoksit prekürsörünün, methanol ve iv asetonitrilden oluşan çözücü ortamında hidrolizi ile elde edilmiştir. İşlem sonucunda, 0.7 - 1.2  m boyut aralığında, 277.4 m 2 /g yüzey alanına sahip küreler sentezlenmiştir. Küreler , yapısına altın nanopartiküllerin bağlanabilmesi için Aminopropiltrietoksisilan (APTES) ile muamele edilmiş ve yapısına fonksiyonel amin grubu eklenmiştir. Katalizör destek m addeleri, Turkevich ve Martin metotlarıyla sentezlenen, sırasıyla 12 ve 3 nm boyutlarına sahip altın nanopartiküllerinin çözeltilerine ayrı ayrı eklenmiş ve bu nanopartiküllerle dekore edilmişlerdir. Altın nanopartiküllerle dekore edilmiş ve edilmemiş kito san mikrojel tanecikler ve TiO 2 küreler taramalı elektron mikroskobu, geçirimli elektron mikroskobu, X - ışını kırınım spektrofotometresi, EDX ve azot adsorpsiyon - desorpsiyon yöntemiyle yüzey alanı analizi ile karakterize edilmişlerdir. Heterojen katalizörl er 4 - Nitrofenolün katalitik indirgenmesi işleminde kullanılmışlardır. Küçük altın nanopartikülllerin elektron transfer karakteristiklerinden dolayı, Martin AuNP ile dekore edilmiş kitosan mikrojel taneciklerin ve TiO 2 kürelerin Turkevich AuNP ler ile dekor e edilenlerle kıyaslandığında plazmonik katalitik aktivitede önemli bir gelişime yol açtığı gözlenmiştir. 2.5 % (w/w %) Martin AuNp yükleme miktarına sa hip 10 mg Au/Kitosan katalizörün, 7.5 ppm başlangıç konsantrasyonuna sahip 4 - Nitrofenolü 12 dakika s onununda tamamen indirgediği gözlenmiştir. %2 Martin AuNp yükleme miktarına sahip 12.5 mg Au/TiO 2 katalizörün ise 7.5 ppm başlangıç konsantrasyonuna sahip 4 - Nitrofenolü 0 saniye sonunda tamamen indirgediği gözlenmiştir. Katalizörlerin geri kazanımının ve aynı reaksiyon şartlarında tekrar kullanılmasının mümkün olduğu gözlenmiştir. Literatürde önerilen benzer maddelerin farklı formlarını veya farklı maddelerin benzer formlarını içeren heterojen katalizörlerin kullanıldığı giderilme yöntemleriyle karşıla ştırıldığında, 4 - Nitrofenol bertarafının, üretilen Au/Kitosan ve Au/TiO 2 katalizörlerin varlığında yürütülen katalitik indirgeme yöntemiyle daha hızlı ve daha yüksek verimle gerçekleştiği belirlenmiştir. Bu çalışmayla, ilk kez, basit üretim yöntemleriyle v e kısa zamanda, enerji tasarruflu, biyouyumlu, yüksek katalitik aktiviteye sahip mikrojel tanecik formunda Au/kitosan ve özgün boyut ve yapıya sahip küre formunda Au/TiO 2 üretilmiştir. Mekanik dayanımı yüksek, yüksek metal etkileşim kapasitesine sahip dest ek maddelerine yeni bir kullanım alanı kazandırılmıştır.tr_TR
dc.contributor.departmentKimya Mühendisliğitr_TR


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