Metal organik kafes yapı katkılı hibrit polimerik membranlar ile pervaporatif desalinasyon uygulaması
Yükleniyor...
Dosyalar
Tarih
2023
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Bursa Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Su, yeryüzündeki tüm canlılar için en değerli doğal kaynaktır ve hayati öneme sahiptir. Dünya'nın %75'i sudur fakat, içme suyu ve tatlı su kaynakları sayısı azdır. Kullanıma uygun tatlı su kaynakları (%3) bir çok nedene bağlı olarak gün geçtikçe azalmaktadır. Bu durumun başlıca nedenleri; nüfus yoğunluğunun artması, sanayileşme ile artan su tüketimi, ilklim değişikliği ve kuraklık olarak gösterilebilir. Dolayısıyla, dünya üzerinde yaklaşık %71 oranında bulunan deniz suyundan alınan tuzlu suyu desalinasyon işlemi ile tatlı suya dönüştürülebilir olması temiz suya ulaşabilmek adına iyi bir çözüm ve alternatif haline gelmiştir. Bu çalışmada desalinasyon için pervaporasyon prosesi kullanılmıştır. Pervaporasyon prosesi ise düşük maliyete sahip olması, işletiminde zararlı ve maliyetli kimyasal kullanılmaması, yüksek oranda ayırma performansı göstermesi, kolay opere edilmesi ve hassas ve yakın kaynama noktalarına sahip karışımların ayrılmasında gelecek vaadeden özelliklere sahip olmasndan dolayı büyük ilgi görmektedir. Bu amaçla pervoparatif desalinasyon prosesinde üstün membran oluşturma kabiliyeti, işleme kolaylığı, bol miktarda bulunabilirliği ve yüksek hidrofiliteye sahip olma özelliklerinden dolayı Polivinil alkol (PVA) ve yüksek ısıl, kimyasal ve mekanik dirençlerinin yanı sıra oksidatif direnç gibi üstün karakteristik avantaja sahip olan hidrofobik Polivinilidin Florür (PVDF) kullanılarak sentezlenmiştir. Bu membranlara son dönemde araştırmaları artan zeolitik imidazolat kafes yapısına sahip, esnek, yüksek termal ve kimyasal stabilite, kalıcı gözenek boyutu ve şekline sahip olmasından dolayı ZIF-8 ve hidrofilik yapısı, pratik kolay sentezlenebilen metal organik kafes yapısına sahip HKUST-1'in eklenmesiyle oluşturulan hibrit membranlar ile pervaporatif desalinasyon deneyleri yapılmıştır. Hazırlanan bu membranların akı ve tuz giderim performansını iyileştirmek amacıyla metal organik kafes yapılar (MOF) ZIF-8 ve HKUST-1 katkı maddeleri olarak kullanılarak karma matrisli hibrit membranlar sentezlenmiştir. Sentezlenen bu membranlar üzerinde akı ve tuz gideriminde sistemin operasyon sıkcaklığının ve beslemedeki tuz konsantrasyonun etkisi gözlemlenmiştir. Membranların karakterizasyonu için SEM, FT-IR, XRD, TGA ve temas açısı analizleri yapılmıştır. ZIF-8 ve HKUST-1 katkısının sentezlenen membranlarda homojen iyi bir dağılım sergilediği gözlenmiştir. En iyi ayırma ve tuz reddi veren deney parametreleri baz alınarak desalinasyon deneyleri gerçekleştirilmiştir. Yapılan deneyler sonucu ZIF-8 ve HKUST-1 içeren membranların akıyı arttırdığı görülmüştür. Sentezlenen PVDF/ HKUST-1 katkılı hibrit membranda %99,94 oranında tuz giderimine sahip %0,75 HKUST-1 konsantrasyonunda sentezlenen membrana aittir. PVA/ZIF-8 membranda ise optimum operasyon koşulları besleme tuz konsantrasyonu %2, operasyon sıcaklığı 60 °C olarak seçilmiş ve desalinasyon tesleri yapılmış ve bu parametrelerde %99'un üzerinde bir oranla verimli bir tuzlu su giderim performansı elde edilmiştir.
Water is the most valuable natural resource for all living things on earth and is of vital importance. Although 75% of the Earth is water, fresh water resources suitable for drinking water and use are quite scarce. The available freshwater resources (0.3%) are decreasing day by day due to drought, climate change, industrialization and increasing population density. Therefore, desalination has become a good solution to deliver clean water to the community, converting salt water into fresh water from the almost unlimited supply of seawater. In this study, pervaporation(PV) process is used for desalination. Pervaporation has attracted a lot of attention due to its low energy consumption, easy operation, low cost, high separation performance and promising features for the separation of mixtures with sensitive and close boiling points. For this purpose, Polyvinyl alcohol (PVA) was synthesized for its superior membrane forming ability, ease of processing, abundant availability and high hydrophilicity in pervaporative desalination process and hydrophobic Polyvinylidine Fluoride (PVDF) which has the advantage of high thermal, chemical and mechanical resistance as well as oxidative resistance. Pervaporative desalination experiments were carried out with hybrid membranes formed by the addition of ZIF-8, which has a zeolitic imidazolate framework structure, high thermal and chemical stability, permanent pore size and shape, and flexibility properties, and HKUST-1, which is a practical and easily synthesizable metal organic framework (MOF) structure with high hydrophilic structure. The effects of ZIF-8 and HKUST-1 added to PVA and PVDF membranes, feed salt concentration and operation temperature on flux and salt removal were investigated. Optimum loading rates, optimum operating temperature and optimum feed salt concentration by weight were determined for both hybrid membranes. In order to improve the flux and desalination performance of these membranes, mixed matrix membranes were obtained by using metal organic framework structures ZIF-8 and HKUST-1 as additives. The effect of feed salt concentration and operation temperature on flux and desalination of hybrid membranes was investigated. Optimum loading rates, optimum operating temperature and optimum feed salt concentration by weight were determined for both hybrid membranes. SEM, FT-IR, XRD, TGA and contact angle analyses were performed for the characterization of the membranes. It was observed that ZIF-8 and HKUST-1 doping exhibited a good dispersion in the membrane. Desalination experiments were carried out based on the experimental parameters giving the best separation and salt rejection. As a result of the experiments, it was observed that membranes containing ZIF-8 and HKUST-1 increased the flux. The highest flux value of 99.94% in the synthesized PVDF / HKUST-1 doped hybrid membrane belongs to the membrane with 0.75% HKUST-1 concentration. In the PVA/ZIF-8 membrane, a ZIF-8 loading rate of 0.2% was found at a temperature of 60 °C and a feed salt concentration of 2 wt%. Pervaporative desalination tests of seawater under optimum operating conditions were carried out and removal performance above 99% was obtained.
Water is the most valuable natural resource for all living things on earth and is of vital importance. Although 75% of the Earth is water, fresh water resources suitable for drinking water and use are quite scarce. The available freshwater resources (0.3%) are decreasing day by day due to drought, climate change, industrialization and increasing population density. Therefore, desalination has become a good solution to deliver clean water to the community, converting salt water into fresh water from the almost unlimited supply of seawater. In this study, pervaporation(PV) process is used for desalination. Pervaporation has attracted a lot of attention due to its low energy consumption, easy operation, low cost, high separation performance and promising features for the separation of mixtures with sensitive and close boiling points. For this purpose, Polyvinyl alcohol (PVA) was synthesized for its superior membrane forming ability, ease of processing, abundant availability and high hydrophilicity in pervaporative desalination process and hydrophobic Polyvinylidine Fluoride (PVDF) which has the advantage of high thermal, chemical and mechanical resistance as well as oxidative resistance. Pervaporative desalination experiments were carried out with hybrid membranes formed by the addition of ZIF-8, which has a zeolitic imidazolate framework structure, high thermal and chemical stability, permanent pore size and shape, and flexibility properties, and HKUST-1, which is a practical and easily synthesizable metal organic framework (MOF) structure with high hydrophilic structure. The effects of ZIF-8 and HKUST-1 added to PVA and PVDF membranes, feed salt concentration and operation temperature on flux and salt removal were investigated. Optimum loading rates, optimum operating temperature and optimum feed salt concentration by weight were determined for both hybrid membranes. In order to improve the flux and desalination performance of these membranes, mixed matrix membranes were obtained by using metal organic framework structures ZIF-8 and HKUST-1 as additives. The effect of feed salt concentration and operation temperature on flux and desalination of hybrid membranes was investigated. Optimum loading rates, optimum operating temperature and optimum feed salt concentration by weight were determined for both hybrid membranes. SEM, FT-IR, XRD, TGA and contact angle analyses were performed for the characterization of the membranes. It was observed that ZIF-8 and HKUST-1 doping exhibited a good dispersion in the membrane. Desalination experiments were carried out based on the experimental parameters giving the best separation and salt rejection. As a result of the experiments, it was observed that membranes containing ZIF-8 and HKUST-1 increased the flux. The highest flux value of 99.94% in the synthesized PVDF / HKUST-1 doped hybrid membrane belongs to the membrane with 0.75% HKUST-1 concentration. In the PVA/ZIF-8 membrane, a ZIF-8 loading rate of 0.2% was found at a temperature of 60 °C and a feed salt concentration of 2 wt%. Pervaporative desalination tests of seawater under optimum operating conditions were carried out and removal performance above 99% was obtained.
Açıklama
Anahtar Kelimeler
Kimya Mühendisliği, Chemical Engineering
