Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Fractionation of Guaiacyl and Syringyl-Lignin Units Using Organic Solvent Nanofiltration(Elsevier, 2026) Croes, Tim; Dutta, Abhishek; Van Aelst, Korneel; Sels, Bert; Van der Bruggen, Bart; Cornet, IrisA major obstacle to employing the full potential of lignin-based aromatics is the fractionation of the monomers present in lignin, specifically the separation of guaiacyl (G) and syringyl (S) units, which possess nearly identical molecular weights (196 Da versus 166 Da) and dimensions, and identical functional groups. Such similarities make their separation highly challenging using conventional techniques and are generally considered beyond the capabilities of size-based membrane processes. This study examines the feasibility of organic solvent nano-filtration for fractionation of guaiacyl and syringyl units, and how membrane and process parameters affect separation of these two molecules. Sixteen commercially available membranes were tested with methanol and ethyl acetate as solvents. The results demonstrate that, despite the extreme similarity of the solutes, selective separation is achievable and is primarily governed by membrane material and solvent selection rather than the pore size-based molecular weight cut-off. Polyimide-based solvent-resistant membranes exhibited the highest selectivity, with a maximum observed separation factor of 3.33 obtained using a DuraMemTM 500 membrane in methanol. These findings demonstrate the potential of nanofiltration to address previously unresolved separation challenges in lignin valorization and provide a basis for further process development.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: 13Citation - Scopus: 18Integrated Pressure-Driven Membrane Separation Processes for the Production of Agricultural Irrigation Water From Spent Geothermal Water(Elsevier, 2022) Jarma, Yakubu Abdullahi; Karaoğlu, Aslı; Tekin, Özge; Senan, Islam Rashad Ahmed; Baba, AlperThe application of different pressure-driven membranes to treat the spent geothermal water to be used for agricultural irrigation was explored in this study. Firstly, individual performances of different commercially available nanofiltration (NF) and reverse osmosis (RO) membranes attached to a mini-pilot membrane test system were studied. For the single membrane test TR-NF and NF90 as NF membranes and TR-BWRO, Vontrone, TR-SWRO and BW30 as RO membranes were employed while combination of TR-NF with TR-BWRO, Vontrone, TR-SWRO and BW30 was employed in the integrated study (with and without pH adjustment).When performances of individual membranes were investigated, the permeate fluxes obtained it was found that there was no significant flux drop with the experimental time (4 h) in all the studies. In terms of boron removals, boron was partially removed in single membrane study as 22.7–23.6% and 30.6–56.8% by NF and RO membranes, respectively. For the integrated NF + RO membrane configuration (without pH adjustment), boron removals were in the range of 42.1–59.4% while 91.3–95.4% of boron removal was obtained in the integrated NF + RO (at elevated pH). It was found that the produced water complied with class I quality with respect to irrigation water parameters with the exception of boron and sodium adsorption ratio (SAR), while the pH of the product water in the integrated NF + RO study at elevated pH was found to be in class III. Hence, produced water will be suitable (class II) for irrigation if 30% of well water should be blended with the product water in the integrated NF + RO studies (with and without pH adjustment) as well as pH adjustment when necessary.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: 58Citation - Scopus: 59Assessment of Different Nanofiltration and Reverse Osmosis Membranes for Simultaneous Removal of Arsenic and Boron From Spent Geothermal Water(Elsevier, 2021) Jarma, Yakubu A.; Karaoğlu, Aslı; Tekin, Özge; Baba, Alper; Ökten, H.Eser; Tomaszewska, Barbara; Kabay, NalanOne of the factors that determine agricultural crops’ yield is the quality of water used during irrigation. In this study, we assessed the usability of spent geothermal water for agricultural irrigation after membrane treatment. Preliminary membrane tests were conducted on a laboratory-scale set up followed by mini-pilot scale tests in a geothermal heating center. In part I, three commercially available membranes (XLE BWRO, NF90, and Osmonics CK- NF) were tested using a cross-flow flat-sheet membrane testing unit (Sepa CF II, GE-Osmonics) under constant applied pressure of 20 bar. In part II, different spiral wound membranes (TR-NE90-NF, TR-BE-BW, and BW30) other than the ones used in laboratory tests were employed for the mini-pilot scale studies in a continuous mode. Water recovery and applied pressure were maintained constant at 60% and 12 bar, respectively. Performances of the membranes were assessed in terms of the permeate flux, boron and arsenic removals. In laboratory tests, the permeate fluxes were measured as 94.3, 87.9, and 64.3 L m?2 h?1 for XLE BWRO, CK-NF and NF90 membranes, respectively. The arsenic removals were found as 99.0%, 87.5% and 83.6% while the boron removals were 56.8%, 54.2%, and 26.1% for XLE BWRO, NF90 and CK-NF membranes, respectively. In field tests, permeate fluxes were 49.9, 26.8 and 24.0 L m?2 h?1 for TR-NE90-NF, BW30-RO and TR-BE-BW membranes, respectively. Boron removals were calculated as 49.9%, 44.1% and 40.7% for TR-BE-BW, TR-NE90-NF and BW30-RO membranes, respectively. Removal efficiencies of arsenic in mini-pilot scale membrane tests were all over 90%. Quality of the permeate water produced was suitable for irrigation in terms of the electrical conductivity (EC) and the total dissolved solids (TDS) for all tested membranes with respect to guidelines set by the Turkish Ministry of Environment and Urbanisation (TMEU). However, XLE BWRO, CK-NF and NF90 membranes failed to meet the required limits for irrigation in terms of boron and arsenic concentrations in the product water. The permeate streams of TR-BE-BW, TR-NE90-NF and BW30-RO membranes complied with the irrigation water standards in terms of EC, TDS and arsenic concentration while boron concentration remained above the allowable limit. © 2020 Elsevier B.V.