Aquaporin z eklentili düz plaka nanofiltrasyon membranların üretimi, karakterizasyonu ve organik madde giderimi
Aquaporin z embedded flat sheet nanofiltration membranes production, characterization and removal of organic matter
Yazar: ENİSE PEKGENÇ
Danışman: PROF. DR. İSMAİL KOYUNCU
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Çevre Mühendisliği Ana Bilim Dalı / Çevre Bilimleri ve Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2018
Konu: Çevre Mühendisliği = Environmental Engineering

Özet:
21.yy'ın en önemli sorunlarından olan su kıtlığı ve yüksek enerji ihtiyacı duyan arıtım prosesleri bilim insanlarını yeni teknolojiler geliştirmeye ve yeni çözüm yolları aramaya teşvik etmektedir. Bu sorunlara çözümler getirecek teknolojilerin başında ise membran prosesleri gelmektedir. 1960'lı yıllardan günümüze kadar olan süreçte endüstriyel gelişimde hızla yol kat eden membran teknolojileri gerek desalinasyon gerek endüstriyel suların arıtılması ve gerekse içme suyu arıtımında etkinliğini arttırmaktadır. Membran proseslerde yapılan araştırmalarda nanopartiküllerin ve biyolojik elementlerin dahil edilmesinin membran performanslarını arttırdığı bildirilmiştir. Özellikle son yıllarda aquaporinler olarak bilinen su kanalı proteinlerinin, membranlara dahil edilerek su arıtma açısından önemli bir cazibe haline geldiği bilinmektedir. Bu çalışmada, nanoteknoloji ve membran teknolojisinin avantajlarının bir arada bulunduğu etkili arıtım sağlayabilen nanofiltrasyon membranlarının elde edilmesi amaçlanmaktadır.
Bu tez çalışması kapsamında AquaporinZ (AqpZ) eklentili membranlar üretilerek, yüksek akı ve yüksek organik madde giderimi sağlayan membran üretimi hedeflenmektedir. Literatürde Aquaporin eklentili membranlarla organik madde giderim verimi üzerine bir çalışma bulunmamaktadır. Ayrıca bu çalışmada lipozom konsantrasyonunun akı ve giderim üzerindeki etkinliğide araştırılmaktadır. 
Nanofiltrasyon seviyesinde üretilmiş düz plaka membranlar için destek tabakası olarak Polisülfon (PSf, P-3500), PVP-K15 ve PVP-K30 ile üretilmiş destek tabakası kullanılmıştır. UF seviyesindeki destek tabaka membranının NF seviyeye getirilmesi ince film komposit ara yüzey polimerizasyon yöntemiyle gerçekleştirilmiştir. NF seviyesinde üretilen membranların optimizasyonunda ince film kaplaması sırasında kullanılan amin monomerin bekletme süresi ve  AquporinZ proteinin içerisine yerleştirildiği DOPC lipozom konsanstrasyonu parametlerinde değişiklik yapılmıştır. Amin monomerin bekletme süreleri 2 dk ve 15 dk olarak uygulanmıştır. DOPC lipozom konsantrasyonu 0.1 mg/ml ve 0.5 mg/ml olarak kaplama gerçekleştirilmiştir. Kaplama sonrasında elde edilen membran çeşitleri; İFK 2 dk, İFK 15 dk, 0.1 mg/ml DOPC 2 dk, 0.1 mg/ml DOPC 15  dk, 0.5 mg/ml DOPC 2 dk ve 0.5 mg/ml DOPC 15 dk şeklindedir. Üretilen membranların tuz tutunum performansının belirlenmesinde 1000 ppm'lik MgSO4 ve NaCl  tuz çözeltileri kullanılmıştır. Organik madde giderim performansının belirlenmesinde ise hümik asit ve tanik asit çözeltileri kullanılmıştır. Amin monomer bekletme süresinin arttırılması İFK ve AquaporinZ eklentili membranlarda membranlarda saf su akı artışını sağlamıştır. Lipozom konsantrasyonunun arttırılması da membranlar üzerinde ciddi bir akı artışına sebep olsada tuz tutunumu gideriminde aynı oranda düşmesine sebep olmuştur. Organik madde giderim verimlerine bakıldığında ise AqpZ katkısının organik madde akısı  üzerinde olumlu katkı sağladığı görülmektedir.

Abstract:
The most important problems of the 21st century, water scarcity and high energy demanding treatment processes. These reasons encouraged scientists to develop new technologies and to find new solutions. Membrane processes are cutting-edge of technology that will bring solutions to these problems. Membrane technologies that make rapid progress in industrial development from the 1960s to the present day increase efficiency of both desalination and industrial waters treatment and, if necessary, drinking water treatment. Studies in membrane processes have reported that incorporation of nanoparticles and biological elements enhances membrane performance. It is known that water channel proteins, known as aquaporins in recent years, have become an important attraction in terms of water treatment by including them in membranes. In this work, it is aimed to obtain nanofiltration membranes that can provide effective treatment that combines the advantages of nanotechnology and membrane technology.
Within the scope of this thesis, it is aimed to produce membranes which have high flux and high organic matter removal by producing membranes with added AquaporinZ.   In the literature, there is no study on the organic matter removal efficiency with the AqpZ embedded  membranes. It is also being investigated the flux and efficacy of the liposome concentration in this study.
Why is important to remove organic matter? Because the presence of DOM in a variety of water sources is a major concern in water treatment and a better refinement has been a focus for environmental scientists and engineers. DOM causes not only unpleasant tastes and odors but also various complexation processes with harmful (emerging) organic / inorganic chemicals (eg Endocrine disrupting compounds, pharmaceuticals, heavy metals). In addition, NOM causes the formation of byproducts that have toxic effects on human health, such as disinfecting products (DBPs) such as Haloacetic acids (HAAs) and Trihalomethanes (THMs) during disinfection with chlorine. Therefore, in order to be protected from the effects on public health, it is necessary to remove them or their precursor. 
Natural surfactants such as humic acids (HA) and tannic acids (TA), which are common in the NOM structure, are widely dispersed in the environment and various studies are being carried out to treat them. However, there is still a lack of information on the treatment of HA and TA from surface waters and wastewater. In this study, the effect of AqpZ-embedded membranes on HA and TA degradation was examined in comparison with IFK membranes.

For the flat sheet membranes produced at the nanofiltration level, the supported layer produced with polysulfone (PSf, P-3500), PVP-K15 and PVP-K30 was used as the supported layer. The NF level of the UF-level support layers was coated membrane was achieved by the thin film composite method. In the optimization of the membranes produced at the NF level, the parameters of the DOPC liposome concentration parameters in which the amine monomer used during the thin film coating were placed in the retention time and the AquporinZ protein were changed. Amine monomer retention times were 2 min and 15 min. DOPC liposome concentration 0.1 mg / ml and 0.5 mg / ml. Membrane types obtained after coating; TFC 2 min, TFC 15 min, 0.1 mg / ml DOPC 2 min, 0.1 mg / ml DOPC 15 min, 0.5 mg / ml DOPC 2 min and 0.5 mg / ml DOPC 15 min. 1000 ppm MgSO4 and NaCl salt solutions were used to determine the salt binding performance of the membranes produced. Humic acid and tannic acid solutions were used to determine the organic removal performance.  When the characterization results are examined of the produced membranes, it can be seen that the AqpZ additive improves the membrane's properties. Especially, hydrophilic membranes were obtained with AqpZ contribution when compared to UF support and IFK membrane in contact angle values. Increasing the liposome concentration also contributes to membrane hydrophilicity. It can also be said that the 15 min coating contributes to the membrane hydrophilicity compared to the 2 min membranes. It is anticipated that AqpZ embedded membranes may reduce the tendency of organic substances in hydrophobic structure to contamination and to prevent clogging problems because of increasing hydrophilicity. When the surface load values are considered, it is seen that AqpZ embedded membrane is more effective in 2 min membrane coating. Surface roughness values showed that high liposome concentration increases the surface roughness values, although there was improvement according to TFC values at 0.1 mg / ml DOPC coatings.  

When the flux values and the performance of rejection values of the produced membranes are considered, it is seen AqpZ embedded contribute to the flux values of membranes. In the yield of MgSO4 and NaCl removal, the increase in liposome concentration negatively affects the rejection values. When SEM images are examined, it is thought that the increase of the liposome concentration causes the deformation of pores in the polyamide layer. So, the removal efficiency decreased. The most effective membrane is 0.1 mg / ml DOPC 2 min membrane with recovery value of 94.3% and flux 13.3 L / m2 h. In addition, 0.1 mg / ml DOPC 2 min maintains its stability with the increase of the pressure of the membrane . This may be expressive of the stability of the AqpZ at high pressure. In 15 min membranes, the salt uptake decreased to 49%. Considering yield reductions on 0.5 mg / ml DOPC and 15 min membranes,  there will be some optimization in future works. For instance, It is possible to determine of the amine monomer waiting period between 2 and 15 min and to increase the flow and maintain the efficiency at the effective level. In addition, the heat application effect can be investigated by obtaining two membranes, with and without heat post treatment in the determined amine monomer retention time. Moreover, an optimal liposome concentration can be determined for AqpZ-added membranes by testing a concentration value between 0.1 mg / ml and 0.5 mg / ml DOPC concentration. Also, It is possible to investigate whether the liposomes can be better embedded in the polyamide layer by increasing the TMC time.
It is observed that humic acid yields are higher than tannic acid removal yields. This may be the size of the humic acid is larger than the tannic acid, and that our membranes are hydrophilic and the humic acid is hydrophobic. TOC removal efficiencies in humic acid and tannic acid filtration are increased with AqpZ embedded and liposome concentration increasing. This is thought to be due to the hydrophilic properties increasing with AqpZ embedded and higher liposome concentration. When the yields of humic acid and tannic acid are examined, it is considered that the mechanism which is effective in the removal efficiency depends on the dimensional separation (steric effect). 
When UV 254 removal efficiencies are examined, it is seen that the membranes are higher UV 254 nm removal than TOC removal efficiencies. UV result shows the removal efficiency of aromatic structure. It can be explained in the case of  both aromatic and aliphatic structures are investigated in TOC and the aliphatic structures are smaller than the aromatic structure and can not be retained.
As a result, when both salt retention flux and organic removal efficiency are taken into consideration, it is seen that positive results are obtained in flux and removal efficiency with the addition of AqpZ. Applying the above-mentioned optimization options, it is predicted that more effective AqpZ embedded membranes can be obtained with higher flow and removal efficiencies.