Bazı atık biyokütle kaynaklarından 5-hidroksimetilfurfural ve levulinik asit eldesi için katı asit katalizörlerin geliştirilmesi ve aktivitelerinin incelenmesi
Küçük Resim Yok
Tarih
2019
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Bursa Teknik Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Son yıllarda ucuz ve bol bulunması nedeniyle etkin kullanılan biyokütle kaynakları yenilenemeyen fosil yakıt kaynaklarının yerini almaya başlamış ve bilim insanlarının dikkatini çeken önemli bir araştırma konusu haline gelmiştir. Biyokütle materyallerinden çeşitli biyo-bazlı karbon, membran, lif ve süperhidrofobik malzemeler hazırlanmakta, bu malzemeler kataliz, çevre bilimi, enerji üretimi ve yapay zeka gibi alanlarda kullanılmaktadır. Lignoselülozik ve selülozik biyokütle kaynaklarından elde edilen umut vaadeden katma değeri yüksek bileşiklerin başında tetrahidrofuran, süksinik asit, 2,5-dimetilfuran, aminolevulinik asit, vb. birçok maddenin sentezinde önemli başlangıç maddeleri olan 5-HMF ve LA gelmektedir. Bu çalışmada, tarımsal ve endüstriyel biyokütle atıklarından, biyokütle türevli karbon katı asit katalizör eşliğinde sulu ortamda yüksek verimle 5-HMF ve LA üretilmesi hedeflenmiştir. Lignoselülozik biyokütle olarak mısır samanı ve buğday samanı, selülozik biyokütle olarak hav ve linter, model bileşik olarak ise mikrokristalin selüloz kullanılmıştır. Biyokütle materyallerinin değerli kimyasallara dönüşümü için iki farklı hidrotermal yöntem kullanılmıştır. İki basamaklı dönüşümde öncelikle biyokütle materyallerinin en küçük monomerlerine kadar otohidroliz ile parçalanması, ardından katalizör kullanımıyla 5-HMF ve LA'ya dönüşümü sağlanmıştır. İkinci yöntemde ise, biyokütle materyalleri ve katalizörün aynı ortama konulmasıyla hem hidroliz işlemi hemde dönüşüm gerçekleştirilmiştir. Her iki yöntemde de farklı biyokütle materyalleri kullanılarak, reaksiyon süresi, sıcaklığı, katalizör miktarı ve derişim optimizasyonları gerçekleştirilmiştir. Genel olarak ürün verimliliği açısından kıyaslandığında tek basamaklı dönüşüm ön plana çıkmaktadır. Elde edilen 5-HMF ve LA verimleri biyokütle materyaline ve kullanılan katalizöre göre değişiklik göstermektedir. Bu çalışmaya kapsamında laboratuvar ortamında farklı kimyasal ve fiziksel özelliklere sahip sekiz farklı heterojen katı asit katalizör hazırlanmıştır. Katalizörlerin ve biyokütle materyallerinin karakterizasyon çalışmaları; elemental analiz, ICP-OES, FT-IR, SEM, XRD, Raman, XRF analizleri yapılarak tamamlanmıştır. BT300-Fe3O4 katalizörü reaksiyon ortamından magnetit özelliği sayesinde kolay ayrılması, dönüşümde katalitik aktivitesinin yüksek olması ve herhangi bir aktivasyon işlemine gerek duymadan en az 5 kez kullanılabilmesi nedeniyle lignoselülozik biyokütlelerin dönüşümünde öne çıkmaktadır. Hazırlanan katalizörlerin aktiviteleri Amberlist-15 ile kıyaslandığında, BT300S katalizörü biyokütle materyallerini hem glukoza parçalama hem de LA'ya dönüşümde etkin bir rol oynamıştır.
In recent years, biomass resources that are used effectively because of their cheapness and abundant availability have started to take place the non-renewable fossil fuel resources and have become an important research topic that attracts the attention of scientists. Various materials; bio-based carbon, membrane, fiber and superhydrophobic materials prepared from biomass are used in fields such as catalysis, environmental science, energy generation and artificial intelligence. 5-HMF and LA are the promising high value added compounds obtained from lignocellulosic and cellulosic biomass sources used as an important starting chemicals for synthesis of many important chemicals such as tetrahydrofuran, succinic acid, 2,5-dimethylfuran, aminolevulinic acid, etc. In this study, it is aimed to produce 5-HMF and LA from agricultural and industrial biomass wastes in the presence of biomass-derived carbon solid acid catalyst in aqueous medium. Corn straw and wheat straw were used as lignocellulosic biomass, fluff and linter were used as cellulose biomass and microcrystalline cellulose was used as a model compound. Two different hydrothermal methods were followed for the conversion of biomass materials. In two-step conversion, first of all, biomass materials were broken to the smallest monomers by hydrolysis, followed by conversion to 5-HMF and LA. In the second method, both hydrolysis and conversion were performed together in the same medium. In both methods, different biomass materials were used, reaction time, temperature, amount of catalyst and concentration were optimized. In general, when compared to product efficiency, one-step conversion method is the most prominent one. 5-HMF and LA yields were varied to the biomass material and the catalyst that was used. Eight different heterogenous solid acid catalysts with different chemical and physical properties were prepared in our laboratory for this study. Characterization studies of catalysts and biomass materials were completed by elemental analysis, ICP-OES, FT-IR, SEM, XRD, Raman, XRF analysis. The BT300-Fe3O4 catalyst stands out in conversion of lignocellulosic biomass because of its easy separation from the reaction medium due to its magnetite property, high catalytic activity in conversion and its use at least 5 times without any activation process. The activity of the prepared catalysts compared with Amberlyst-15, the BT300S catalyst played an effective role in both decomposition to glucose and conversion to LA.
In recent years, biomass resources that are used effectively because of their cheapness and abundant availability have started to take place the non-renewable fossil fuel resources and have become an important research topic that attracts the attention of scientists. Various materials; bio-based carbon, membrane, fiber and superhydrophobic materials prepared from biomass are used in fields such as catalysis, environmental science, energy generation and artificial intelligence. 5-HMF and LA are the promising high value added compounds obtained from lignocellulosic and cellulosic biomass sources used as an important starting chemicals for synthesis of many important chemicals such as tetrahydrofuran, succinic acid, 2,5-dimethylfuran, aminolevulinic acid, etc. In this study, it is aimed to produce 5-HMF and LA from agricultural and industrial biomass wastes in the presence of biomass-derived carbon solid acid catalyst in aqueous medium. Corn straw and wheat straw were used as lignocellulosic biomass, fluff and linter were used as cellulose biomass and microcrystalline cellulose was used as a model compound. Two different hydrothermal methods were followed for the conversion of biomass materials. In two-step conversion, first of all, biomass materials were broken to the smallest monomers by hydrolysis, followed by conversion to 5-HMF and LA. In the second method, both hydrolysis and conversion were performed together in the same medium. In both methods, different biomass materials were used, reaction time, temperature, amount of catalyst and concentration were optimized. In general, when compared to product efficiency, one-step conversion method is the most prominent one. 5-HMF and LA yields were varied to the biomass material and the catalyst that was used. Eight different heterogenous solid acid catalysts with different chemical and physical properties were prepared in our laboratory for this study. Characterization studies of catalysts and biomass materials were completed by elemental analysis, ICP-OES, FT-IR, SEM, XRD, Raman, XRF analysis. The BT300-Fe3O4 catalyst stands out in conversion of lignocellulosic biomass because of its easy separation from the reaction medium due to its magnetite property, high catalytic activity in conversion and its use at least 5 times without any activation process. The activity of the prepared catalysts compared with Amberlyst-15, the BT300S catalyst played an effective role in both decomposition to glucose and conversion to LA.
Açıklama
Fen Bilimleri Enstitüsü, Kimya Ana Bilim Dalı
Anahtar Kelimeler
Kimya, Chemistry
