Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Citation - WoS: 1Citation - Scopus: 2A New-Generation Poly (ether Imide Sulfone) Based Solvent Resistant Ultrafiltration Membrane for a Sustainable Production of Silica Nanopowder(Elsevier, 2023) Güngörmüş, Elif; Alsoy Altınkaya, SacideThe work presented here demonstrated the feasibility of using a membrane to improve the sustainability of silica nanopowder production. Due to superior chemical resistance, high thermal-oxidative stability, and good processability, poly (ether imide sulfone) has been used for membrane production and modified with amine-functionalized TiO2 nanoparticles. The membrane demonstrated good long-term leaching stability in 40% ethanol and silica synthesis solution and maintained its permeability and rejection characteristics under static and dynamic conditions. Additionally, the high antifouling property of the membrane allowed recovering 99.5% of the nanoparticles. Backwashing with water resulted in a high flux recovery ratio (>93%), and gravity-settling without energy can easily separate silica nanoparticles and water in the backwashing solution. Compared to classical freeze-drying and oven-drying methods, integrating membrane into silica nanopowder production can reduce energy consumption by a factor of 81 and 53. At the same time, the utility cost can be saved by 80% and 69%. Additionally, the solvent and catalyst recovered in the permeate stream can be reused in the synthesis, reducing disposal and purchasing costs. In conclusion, membrane-assisted nanopowder production can minimize the adverse effects caused by commonly used conventional drying methods and make the process more sustainable and environmentally friendly.Article Citation - WoS: 54Citation - Scopus: 62A Positively Charged Loose Nanofiltration Membrane Fabricated Through Complexing of Alginate and Polyethyleneimine With Metal Ions on the Polyamideimide Support for Dye Desalination(Elsevier, 2021) Metecan, Ayşe; Cihanoğlu, Aydın; Alsoy Altınkaya, SacideNowadays, loose nanofiltration (NF) membranes are preferred for dye desalination to achieve high dye/salt selectivity and enable filtration at low operating pressure. However, current fabrication techniques require rigorous reaction conditions and long preparation times. Herein, we used the chelating ability of the polyethyleneimine (PEI) and alginate with the metal ions to fabricate loose NF membranes via a facile approach. The positively charged polyamide imide (PAI)/PEI support was used to build the assembly. Direct attachment of Zn or Fe ions to the PEI chains did not result in a stable complex in the presence of a high salt concentration (1000 ppm NaCl). On the other hand, alginate coated on the support allowed building permanent assemblies after crosslinked with Fe3+ and Zn2+ transition metal ions. The PAI/PEI-Alg-Fe3+ membrane exhibited the highest permeability, excellent antifouling behaviour upon exposure to synthetic textile wastewater, and maintained long-term stability under static and dynamic conditions. Also, the same membrane rejected dyes and coloured substances in real wastewater sample during 72 h continuous filtration. With alginate metal complex formation on a suitable support, a scalable loose NF membrane was manufactured, demonstrating improved throughput value compared to current NF membranes.Article Citation - WoS: 49Citation - Scopus: 55A Facile Approach for Preparation of Positively Charged Nanofiltration Membranes by In-Situ Crosslinking Between Polyamide-Imide and Polyethylenimine(Elsevier Ltd., 2018) Cihanoğlu, Aydın; Alsoy Altınkaya, SacidePolyamide-imides (PAI) are attractive materials for membrane formation due to their high chemical and thermal stability. In this study, we report a facile approach for preparing positively charged nanofiltration (NF) membranes using a one-step process. Polyethylenimine (PEI) was dissolved in a coagulation bath and formed in-situ ionic crosslinking with PAI during phase inversion. The membranes were characterized by attenuated total reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM), contact angle and zeta potential measurements. The most positively charged membrane was obtained when the pH of the coagulation bath was adjusted to 10. This membrane showed a significant decrease in contact angle and surface roughness and increase in the pure water permeability (PWP) compared to the plain PAI membrane. The salt rejection performance of the crosslinked PAI membrane was measured using MgCl2, CaCl2, NaCl and Na2SO4 salts. The rejection of Mg2+ and Ca2+ ions was found to be 95.6% and 90.2%, respectively. The crosslinked membrane showed excellent chemical stability when stored in HCl solution at pH 3 up to 7 days. Antifouling behaviour of the optimized membrane was tested using bovine serum albumin (BSA) and flux recovery ratio of the membrane was found to be 92.2% at the end of 3 h filtration. The results suggest that the positively charged PAI membranes crosslinked with PEI may have a potential in recovering valuable cationic metals from acid mine wastewater.Article Citation - WoS: 62Citation - Scopus: 72Diatomite Reinforced Chitosan Composite Membrane as Potential Scaffold for Guided Bone Regeneration(Elsevier Ltd., 2017) Tamburacı, Sedef; Tıhmınlıoğlu, FundaIn this study, natural silica source, diatomite, incorporated novel chitosan based composite membranes were fabricated and characterized for bone tissue engineering applications as possible bone regeneration membrane. The effect of diatomite loading on the mechanical, morphological, chemical, thermal and surface properties, wettability and in vitro cytotoxicity and cell proliferation on of composite membranes were investigated and observed by tensile test, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), protein adsorption assay, air/water contact angle analysis and WST-1 respectively. Swelling studies were also performed by water absorption capacity determination. Results showed that incorporation of diatomite to the chitosan matrix increased the surface roughness, swelling capacity and tensile modulus of membranes. An increase of about 52% in Young's modulus was achieved for 10 wt% diatomite composite membranes compared with chitosan membranes. High cell viability results were obtained with indirect extraction method. Besides, in vitro cell proliferation and ALP activity results showed that diatom incorporation significantly increased the ALP activity of Saos-2 cells cultured on chitosan membranes. The novel composite membranes prepared in the present study with tunable properties can be considered as a potential candidate as a scaffold in view of its enhanced physical & chemical properties as well as biological activities for bone tissue engineering applications.Article Citation - WoS: 66Citation - Scopus: 73Novel Low-Fouling Membrane Bioreactor (mbr) for Industrial Wastewater Treatment(Elsevier Ltd., 2016) Deowan, Shamim Ahmed; Galiano, Francesco; Hoinkis, Jan; Johnson, Daniel; Alsoy Altınkaya, Sacide; Gabriele, Bartolo; Hilal, Nidal; Drioli, Enrico; Figoli, AlbertoA novel antifouling coating of ultrafiltration (UF) commercial membranes, based on a polymerisable bicontinuous microemulsion (PBM) technique, was developed and tested for the first time in a membrane bioreactor (MBR) using an artificial model textile dye wastewater and compared with a commercial uncoated UF membrane. The results showed that the commercial MBR module faced severe fouling problems whereas the novel coated PBM MBR module reduced the fouling significantly. The analysis of fouling rate using a resistance model confirms that PBM coated membrane has a higher antifouling effect. The antimicrobial properties of the PBM membrane contributed by polymerisable cationic surfactant acryloyloxyundecyltriethylammonium bromide (AUTEAB) guaranteed an anti-biofouling effect preventing the growth of microorganisms on the membrane surface. In addition, the PBM MBR module showed 10±1% higher blue dye removal efficiency and a similar rate of COD removal efficiency of about 95±1% compared to commercial module. However, water permeability was slightly lower due to extra resistance of the PBM coating. Root mean squared (RMS) roughness measurement and analysis of AFM images confirmed that the stable novel membrane coating still existed and showed antimicrobial effect even after 105 days of operation. The results obtained demonstrated the potential of the low fouling PBM membrane.Article Citation - WoS: 52Citation - Scopus: 60A Step Forward To a More Efficient Wastewater Treatment by Membrane Surface Modification Via Polymerizable Bicontinuous Microemulsion(Elsevier Ltd., 2015) Galiano, Francesco; Figoli, Alberto; Deowan, Shamim Ahmed; Johnson, Daniel; Alsoy Altınkaya, Sacide; Veltri, Lucia; De Luca, Giorgio; Mancuso, Raffaella; Hilal, Nidal; Gabriele, Bartolo; Hoinkis, JanAn innovative hydrophilic and anti-fouling coating material for application in membrane technology for wastewater treatment has been developed by polymerization of a polymerizable bicontinuous microemulsion (PBM) and used for surface modification of a commercial flat polyethersulfone (PES) membrane. The novel nanostructured coating has been produced using acryloyloxyundecyltriethylammonium bromide (AUTEAB) as a co-polymerizable surfactant, obtained through a synthetic method characterized by a lower cost and a higher reproducibility compared to other known polymerizable surfactants. The novel composite membranes have been characterized and compared with the uncoated PES membranes. Coated membranes resulted in a smoother surface and a higher hydrophilicity with respect to the uncoated ones, and showed a particular nano-size channel-like morphology making them highly resistant to the fouling phenomenon. The covalent anchorage of the surfactant on the membrane surface ensured the embedment of the molecule in the polymeric matrix avoiding its leaching and also leading the coated membranes to have significant antimicrobial activity, which is very important for reducing the biofouling phenomenon.All these aspects make the tailored coating material an ideal and efficient coating for modifications of commercial membrane surfaces, to be used in membrane processes in wastewater treatment.Article Citation - WoS: 6Citation - Scopus: 7Modeling of Asymmetric Membrane Formation by a Combination of Dry/Wet Phase Inversion Processes(Elsevier Ltd., 2006) Alsoy Altınkaya, SacideThe invention of asymmetric polymer membranes by Loeb and Sourirajan has caused an enormous growth in the field of membrane science and technology. Application areas range from chemical, biomedical to biotechnology industries. Asymmetric membranes are mostly fabricated by a process called phase inversion which can be achieved through four principal methods: immersion precipitation (wet phase inversion), vapor-induced phase separation, thermally induced phase separation and dry-casting. In these techniques, an initially homogeneous polymer solution becomes thermodynamically unstable and phase separates into polymerlean and polymer-rich phases. Structure of these types of membranes is greatly influenced by even slight change in membrane preparation conditions.