GCRIS

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Development of Innovative Polymeric Membranes Using Green Approaches for Water and Energy Sustainability
(01. Izmir Institute of Technology, 2022) Güngörmüş Deliismail, Elif; Altınkaya, Sacide
In this thesis, innovative polymeric membranes with fast, simple, and easily scalable manufacturing procedures were developed to demonstrate the potential of membrane technology in making chemical processes more sustainable. In this scope, firstly, it was focused on minimizing the adverse chemical, environmental, and economic effects of conventional drying processes by integrating membrane technology into the production of nano/microparticles. Acid-resistant polyaniline based ultrafiltration (UF) membrane and solvent-resistant poly (ether imide sulfone) based UF membrane were developed to produce aluminum sulfate powder and silica powder, respectively. The developed high-performance and antifouling membranes made the production of powders more sustainable and environmentally friendly by enabling the recovery of the acid/solvent used in the synthesis and the reduction of energy consumption for drying. The third part of the thesis focused on biodiesel production with a high-performance, antifouling, alumina-calcium oxide catalyst-modified polyethersulfone UF membrane. Combining membrane technology with reaction engineering allowed for the elimination of the catalyst recovery step, shortened the reaction time to reach a desirable yield, and reduced energy consumption, resulting in more sustainable biodiesel production than existing production techniques. In the last part of the thesis, a high-performance, antibiofouling/antibacterial citric acid doped polyaniline based UF membrane was developed. Ensuring sustainability improvement in membrane production in all applications was the main objective of this thesis. By reducing the number of steps in membrane production, the amount of wastewater generated, and toxic waste released during membrane production was minimized, and energy consumption was significantly reduced.
Development of Antifouling Nanofiltration and Antibiofouling Ultrafiltration Polymeric Membranes Using Facile Protocols
(Izmir Institute of Technology, 2021) Cihanoğlu, Aydın; Altınkaya, Sacide; Şeker, Erol
One of the major goals in membrane separation technology is to develop fouling-resistant membranes that can provide a long operating time and low operation costs. This thesis aims to manufacture fouling and biofouling-resistant polymeric nanofiltration (NF) and ultrafiltration (UF) membranes using unique approaches. The first approach was to change coagulation bath composition in the phase inversion technique for manufacturing fouling-resistant polyamide-imide (PAI) based NF and biofouling-resistant polysulfone (PSF)/sulfonated polyethersulfone (PSF-SPES) based UF membranes. To this end, hydrophilic branched polyethyleneimine (PEI) dissolved in the coagulation bath allowed the preparation of a positively charged PAI based NF membrane by forming a covalent bond with the imide group in the PAI. To manufacture antibacterial UF membranes, a strong antibacterial surfactant, cetyltrimethylammonium bromide (CTAB), was dissolved in the coagulation bath and made an electrostatic interaction with SPES at the polymer/bath interface during phase inversion. Both membranes were prepared in a one-step process without using any pore formers in the casting solution. The second approach used in the thesis focused on modification of commercial polyethersulfone (PES) UF membranes with co-deposition of dopamine and CTAB molecules to impart antibiofouling behavior without compromising the pore size and pure water flux of the support. To achieve this task, during modification, an inert physical barrier was created inside the membrane pores by continuously feeding nitrogen gas (N2) from the backside of the support to prevent pore penetration. In the last approach, ultrasound as a green, controllable trigger was used for modifying PSF and PSF-SPES UF membranes with dopamine. The main purpose of using ultrasound was to accelerate the polymerization kinetics of dopamine, hence shortening the modification time.

Phd Degree / Doktora

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