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Öğe Cerium-Doped CuFe-Layered Catalyst for the Enhanced Oxidation of o-Xylene and N,N-Dimethylacetamide: Insights into the Effects of Temperature and Space Velocity(Amer Chemical Soc, 2023) Ocal, Zehra Betul; Keyikoglu, Ramazan; Karagunduz, Ahmet; Yoon, Yeojoon; Khataee, AlirezaVolatile organic compounds (VOCs) are among the most potential pollutant groups that cause air quality degradation because of their toxic effects on human health. Although catalytic oxidation is an effective method for VOC removal, further studies are required to develop more efficient and affordable catalysts. In this study, cerium (Ce) was doped into a CuFe-layered material (Ce-CuFe) to improve the catalytic oxidation efficiencies of N,N-dimethylacetamide (DMAC) and o-xylene. The synthesized catalyst was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analysis. XRD analysis confirmed the successful doping of Ce atoms into the CuFe-layered structure, while in the SEM and TEM images the catalyst appeared as uniformly distributed two-dimensional plate-like particles. The catalytic oxidation performance of the Ce-CuFe was investigated at six temperatures between 200 and 450 degrees C and three space velocities in the range of 31000-155000 mLh(-1)g(-1) for the oxidation of DMAC and o-xylene, which functioned as polar and nonpolar solvents, respectively. At 200 degrees C, the Ce-CuFe catalyst performed 50% greater when oxidizing o-xylene while exhibiting a DMAC oxidation efficiency that was 42% greater than that achieved using undoped CuFe. The Ce-CuFe could remove DMAC and o-xylene with an efficiency higher than 95% at 450 degrees C. Furthermore, Ce-doped CuFe exhibited high resistance against moisture and outstanding reusability performance with only a 5.6% efficiency loss after nine reuse cycles. Overall, the incorporation of Ce into a CuFe-layered material is a promising strategy for the oxidation of various VOCs.Öğe Development of ZnFeCe Layered Double Hydroxide Incorporated Thin Film Nanocomposite Membrane with Enhanced Separation Performance and Antibacterial Properties(Mdpi, 2023) Balcik, Cigdem; Ozbey-Unal, Bahar; Sahin, Busra; Buse Aydin, Ecem; Cifcioglu-Gozuacik, Bengisu; Keyikoglu, Ramazan; Khataee, AlirezaDeveloping thin-film nanocomposite (TFN) membranes by incorporating nanomaterials into the selective polyamide (PA) layer is an effective strategy to improve separation and antibacterial properties. In this study, TFN nanofiltration (NF) membranes were fabricated by interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC) with the addition of Zinc-Iron-Cerium (ZnFeCe) layered double hydroxide (LDH). The improved surface hydrophilicity of TFN membranes was investigated by water contact angle analyses and pure water flux measurements. Successful production of the PA layer on the membrane surface was determined by Fourier-transform infrared (FTIR) analysis. Atomic Force Microscope (AFM) images showed that the addition of LDH into the membrane resulted in a smoother surface. The scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM/EDS) mapping of TFN membrane proved the presence of Ce, Fe, and Zn elements, indicating the successful addition of LDH nanoparticles on the membrane surface. TFN 3 membrane was characterized with the highest flux resulting in 161% flux enhancement compared to the pristine thin film composite (TFC) membrane. All membranes showed great rejection performances (with a rejection higher than 95% and 88% for Na2SO4 and MgSO4, respectively) for divalent ions. Additionally, TFN membranes exhibited excellent antibacterial and self-cleaning properties compared to the pristine TFC membrane.Öğe Fabrication of PSf nanocomposite membranes incorporated with ZnFe layered double hydroxide for separation and antifouling aspects(Elsevier, 2022) Balcik, Cigdem; Ozbey-Unal, Bahar; Cifcioglu-Gozuacik, Bengisu; Keyikoglu, Ramazan; Karagunduz, Ahmet; Khataee, AlirezaHerein, we report the effect of blending of various concentrations of ZnFe layered double hydroxide (LDH) on the filtration, antifouling, and antibacterial performances of Polysulfone (PSf) nanocomposite membranes for BSA and dye separation. ZnFe LDH with a molar ratio of M2+:M3+=3:1 was synthesized by the co-precipitation method. The PSf-ZnFe LDH nanocomposite membranes exhibited higher hydrophilicity (the lowest contact angle value of 64.42 & nbsp;), porosity (up to 58.7), and mean pore radius compared to the pristine PSf membrane. The water flux of the PSf-ZnFe LDH nanocomposite membrane (LDH content of 2.0 wt% of PSf) was 105 L/m(2)h, which is 2.3 times higher than the flux of pristine PSf membrane of 45 L/m(2)h. The rejection ratios for the fabricated membranes were 93%, 83%, and 16% for BSA, reactive red 198, and methylene blue, respectively. Additionally, 2.0 wt% ZnFe LDH incorporated membrane demonstrated better antifouling performance with a flux recovery ratio (FRR) of 95% compared to the pristine PSf membrane with 42% of FRR. Consequently, a bacterial viability inhibition test was utilized to determine the antibacterial properties, and the ZnFe LDH exhibited a high inhibition capacity. The fabricated PSf-ZnFe LDH nanocomposite membranes exhibited a higher filtration, antifouling, and antimicrobial performance as compared to pristine PSf.Öğe Kozmetik sanayi atıksularının boron doped diamond, pla tin ve metal oksit elektrotlar i le elektrooksidasyon prosesinde arıtılması(2024) Can, Orhan Taner; İlhan, Hilal; Keyikoglu, Ramazan; Elibol, Pınar Sevim; Aygun, Ahmet; Isleyen, MehmetBu çalışmada, yüksek kirlilik içeriğine sahip kozmetik atıksuyunun elektroooksidasyon prosesi ile arıtılabilirliği 3 farklı anot kullanılarak araştırılmıştır. Bu amaçla BDD (Boron Doped Diamond), Pt ve RuO2-IrO2 metal-oksit elektrotları kullanılmıştır. Her bir elektrodun toplam organik karbon (TOK) giderim verimleri tespit edilmiştir ve elde edilen veriler karşılaştırılmıştır. 120 dk.’lık deney süresi sonunda TOK giderim verimleri 0.5, 1 ve 1.5 amper akımlar için sırasıyla BDD anot için %31.6, %57.8 ve %68; Pt anot için %25, %36.5 ve %48; RuO2-IrO2 metal-oksit anot için %22.6, %29.8 ve %42.6 olarak elde edilmiştir. Tüm elektrotlar için deney süresi boyunca TOK giderim verimlerinin zamanla arttığı belirlenmiştir. Deney setleri arasında BDD elektrotun en iyi giderim verimini sağladığı ve bu verimin zamanla arttığı görülmüştür. 120 dk.’lık deney süresi sonunda 1.5 amper için, BDD, Pt ve RuO2-IrO2 metal-oksit elektrotlarının en iyi TOK giderim verimleri sırasıyla %68, %48 ve %42.6 idi.Öğe Layered double hydroxides for removing and recovering phosphate: Recent advances and future directions(Elsevier, 2022) Keyikoglu, Ramazan; Khataee, Alireza; Yoon, YeojoonEutrophication is a widespread environmental challenge caused by excessive phosphate. Thus, wastewater engineers primarily aim to limit the phosphate concentration in water bodies. Layered double hydroxides (LDHs) are lamellar inorganic materials containing tunable brucite-like structures. This review discusses the fundamental aspects and latest developments in phosphate removal using LDH-based materials. Based on the divalent cations, Ca, Mg, and Zn-containing LDHs are largely used along with trivalent cations such as Al and Fe owing to their limited toxicities. However, classical LDHs are affected by the presence of co-existing anions, have a narrow working pH range, and have moderate adsorption capacities. Binary LDHs have been designed to be selective towards phosphate by the addition of a third metal such as Zr4+. Developing LDH composites with magnetic, polymeric or carbon materials are feasible approaches for increasing adsorption capacity, stability, and reusability of LDHs. Biochar as a carrier material for LDHs achieved remarkable phosphate adsorption performance and improved LDH dispersion, anion exchange capacity, and ease of separation. The use of recovered phosphate as an SRF, which is a type of bioavailable fertilizer, is a promising approach.Öğe Nanoarchitecturing of CuFeLa layered double hydroxide on graphite felt for photo-electrocatalytic degradation of emerging pollutants(Elsevier Science Inc, 2025) Seifi, Azam; Keyikoglu, Ramazan; Karatas, Okan; Cosut, Bunyemin; Khataee, AlirezaDue to the importance of wastewater decontamination from emerging pollutants, various approaches have been established as treatment processes. In the present study, a graphite felt (GF) electrode was modified with a layered double hydroxide (LDH) to degrade rifampicin in a combined photo-electrocatalytic process. The synthesized CuFeLa LDH was deposited on the GF (CuFeLa LDH@GF) via the electrophoretic deposition method. SEM images showed the uniform coverage of GF fibers by two-dimensional flake-like LDH nanoparticles. The CuFeLa LDH coating improved the electron transfer kinetics of GF and reduced charge transfer resistance. The photo-electrocatalytic process employing the CuFeLa LDH@GF cathode could achieve 79.4% and 65.7% degradation efficiency for rifampicin at pH 6 and 8, respectively. The apparent reaction rate constant (kapp) of the process with CuFeLa@GF (photo-electrocatalysis) was 7.98 times that of the raw GF electrode (photo-electrolysis). This was due to the increased production of hydroxyl radicals (center dot OH), which was shown by radical scavenging and center dot OH trapping experiments. Moreover, the coated electrode had a high stability with only a 4.7% performance loss in 5 successive application tests. The liquid chromatography-mass spectrometry (LC-MS/MS) analysis revealed the intermediates produced during the degradation process. The CuFeLa LDH@GF, with its consistent performance under nearly neutral conditions and catalytic activity over extended periods, indicates potential for effective and environmentally friendly approaches to wastewater treatment.Öğe Peroxydisulfate-assisted sonocatalytic degradation of metribuzin by La-doped ZnFe layered double hydroxide(Elsevier, 2022) Akdag, Sultan; Rad, Tannaz Sadeghi; Keyikoglu, Ramazan; Orooji, Yasin; Yoon, Yeojoon; Khataee, AlirezaMetribuzin is an herbicide that easily contaminates ground and surface water. Herein, La-doped ZnFe layered double hydroxide (LDH) was synthesized for the first time and used for the degradation of metribuzin via ultrasonic (US) assisted peroxydisulfate (PDS) activation. The synthesized LDH had a lamellar structure, an average thickness of 26 nm, and showed mesoporous characteristics, including specific surface area 110.93 m(2) g(-1), pore volume 0.27 cm(3) g(-1), and pore diameter 9.67 nm. The degradation efficiency of the US/La-doped ZnFe LDH/PDS process (79.1 %) was much greater than those of the sole processes, and the synergy factor was calculated as 3.73. The impact of the reactive species on the sonocatalytic process was evaluated using different scavengers. After four consecutive cycles, 10.8 % loss occurred in the sonocatalytic activity of the La-doped LDH. Moreover, the efficiency of the US/La-doped LDH/PDS process was studied with respect to the degradation of metribuzin in a wastewater matrix. According to GC-MS analysis, six by-products were detected during the degradation of metribuzin. Our results indicate that the US/La-doped ZnFe LDH/PDS process has great potential for efficient degradation of metribuzin-contaminated water and wastewater.Öğe Recent advances in boron species removal and recovery using layered double hydroxides(Elsevier, 2023) Akdag, Sultan; Keyikoglu, Ramazan; Karagunduz, Ahmet; Keskinler, Bulent; Khataee, Alireza; Yoon, YeojoonAnthropogenic boron discharge threatens ecosystem health and water quality. Although boron is a micronutrient necessary for plants, animals, and humans, excessive concentrations can have toxic effects. Layered double hydroxides (LDH) are two-dimensional anionic clay materials that exhibit intrinsic anion-exchange properties. In this paper, the use of LDH for the removal and recovery of boron species from water is presented. The main factors that affect boron removal, including the LDH dosage, initial boron concentration, solution pH, temperature, and the presence of other anions, are outlined. For boron removal, LDH containing Mg, Fe, Zn, or Ca cations have been mostly used owing to their limited toxicities and abundance in the environment. The boron removal capacity of LDH can be improved by transforming the layered structure into bimetallic oxides through calcination, increasing not only the surface area but also the interaction with anionic species during their regeneration. The main boron-removal mechanism of LDH is ion exchange with intercalated anions or the surface complexation with the surface groups of the LDH. A major advantage of using LDH for boron removal is the possibility of recovering and reusing the extracted boron. LDH synthesized with boron as the interlayer anion showed slow-release fertilizer properties, suggesting the use of boron-loaded LDH as plant growth regulators.Öğe Synergistic effect of Fe and Co metals for the enhanced activation of hydrogen peroxide in the heterogeneous electro-Fenton process by Co-doped ZnFe layered double hydroxide(Elsevier Sci Ltd, 2022) Keyikoglu, Ramazan; Khataee, Alireza; Orooji, Yasin; Kobya, MehmetHeterogeneous electro-Fenton (EF) is a powerful technology for the removal of emerging organic pollutants from wastewater. However, the development of catalysts with high activity towards the production of (OH)-O-center dot by decomposing H2O2 remains a challenge. Herein, Co-doped ZnFe LDH as a heterogeneous catalyst with 2D plate-like morphology was produced by a co-precipitation method. Co-doping increased the pore volume of ZnFe LDH from 0.188 cm(3)/g to 0.2711 cm(3)/g and pore diameter from 5.305 nm and 9.39 nm. EF process consisted of a hydrothermally activated graphite felt cathode and a platinum plate anode. The Phenazopyridine (PHP) removal efficiency of the EF process in the presence of Co-doped ZnFe LDH is twice that of the electrochemical process. Additionally, Co-doping increased the performance of ZnFe LDH from 60 % to 82 % due to a synergistic effect of redox couples of Fe2+/Fe3+ and Co2+/Co3+. The Co-doped ZnFe LDH/EF process achieved complete removal of PHP in real wastewater in 4 h and at natural pH. After 7 reuse cycles, the catalyst retained 91 % of its performance. The eight by-products of PHP were determined by GC-MS. This work provides a way sustainable approach for the efficient removal of organic pharmaceuticals from wastewaters.Öğe Synthesis of visible light responsive ZnCoFe layered double hydroxide towards enhanced photocatalytic activity in water treatment(Pergamon-Elsevier Science Ltd, 2022) Keyikoglu, Ramazan; Dogan, Irmak Naz; Khataee, Alireza; Orooji, Yasin; Kobya, Mehmet; Yoon, YeojoonIn this study, a ternary layered double hydroxide containing Zn, Co, and Fe transition metals (ZnCoFe LDH) was developed using a co-precipitation procedure. The as-synthesized photocatalyst was evaluated for its perfor-mance in the degradation of methylene blue (MB) under visible light irradiation. The effects of various process conditions including photocatalyst dosage, pollutant concentration, pH, lamp distance, and lamp power were investigated. The ZnCoFe LDH achieved approximately 74% photodegradation efficiency owing to the narrow bandgap of 2.14 eV. The Langmuir-Hinselwood rate constants were calculated as 1.17 min-1 and 3.55 min-1 for photolysis by LED lamp alone and for photocatalysis by LED/ZnCoFe LDH, respectively. The photocatalytic ability of the LDH was attributed to the generation of radical species like center dot OH and O2 center dot-. The photocatalytic degradation intermediates of MB were determined by GC-MS analysis. The catalyst retained its performance throughout seven reuse cycles with only a 4.17% reduction in removal efficiency. The energy per order EEO of the ZnCoFe/LED process in 180 min treatment time was determined as 5.41 kWh.m- 3. order-1. This study shows that ZnCoFe LDH has sufficient activity and photostability for long-term application in photocatalytic water treatment.Öğe Treatment of cosmetic industry wastewater with boron doped diamond, platinum and metal oxide electrodes in electrooxidation process(Pamukkale Univ, 2024) Can, Orhan Taner; Gundogdu, Hilal; Keyikoglu, Ramazan; Elibol, Pinar Sevim; Aygun, Ahmet; Isleyen, MehmetIn this study, treatability of cosmetic wastewater consist high pollution by electrooxidation process was investigated using three different anodes. For this purpose, BDD (Boron Doped Diamond), Pt and RuO2- IrO2 metal -oxide electrodes were used. The total organic carbon (TOC) removal efficiency of each electrode was determined and results were compared. After 120 min of operating time, the TOC removal efficiencies of BDD anode were obtained as 31.6%, 57.8% and 68%; Pt anode were obtained as 25%, 36.5% and 48%; RuO2-IrO2 metal -oxide anode were obtained as 22.6%, 29.8% and 42.6% respectively for 0.5, 1 and 1.5 ampere currents. It is observed that TOC removal efficiency increases with time for all electrodes throughout the operation time. The results showed that BDD electrode provided the best removal efficiency and this efficiency increased by the time of progress. After 120 min of operating time, the best TOC removal efficiencies of BDD, Pt and RuO2-IrO2 metaloxides electrodes were 68%, 48% and 42.6% respectively for 1.5 ampere.Öğe Treatment of intermediate landfill leachate using different anode materials in electrooxidation process(Wiley, 2021) Can, Orhan Taner; Gazigil, Leyla; Keyikoglu, RamazanThis study aims to investigate the performances of widely used anode materials in the treatment of intermediate landfill leachate treatment by electrooxidation (EO) process. The raw leachate was collected from an 8-year-old landfill facility and had a chemical oxygen demand (COD) of 4660 mg/L, biological oxygen demand (BOD5) of 1370 mg/L, and total organic carbon (TOC) of 2260 mg/L. TOC and COD removal efficiencies of Boron-Doped Diamond (BDD), Pt, and four different Ti-based mixed metal oxide (MMO) anodes ((RuO2-TiO2, RuO2-IrO2, PtO2-IrO2, and IrO2-Ta2O5) were compared at the current densities of 25 mA/cm(2), 75 mA/cm(2), and 125 mA/cm(2). At the highest current density, the BDD achieved 100% TOC and COD removal efficiencies in 240 min. BDD was followed by the Pt anode, which achieved 95.53% COD and 92.74% TOC removal efficiencies. The Pt electrode also had the lowest SEC values at all current densities. Although the performances of four MMO electrodes were very close, RuO2-TiO2 achieved a slightly higher performance than the others. It was concluded that Pt anode can be a promising alternative to BDD, which was 18 times more expensive, with its comparable pollutant removal performance and low specific energy consumption.Öğe Vanadium (V)-doped ZnFe layered double hydroxide for enhanced sonocatalytic degradation of pymetrozine(Elsevier Science Sa, 2022) Keyikoglu, Ramazan; Khataee, Alireza; Lin, Hongjun; Orooji, YasinIn ultrasonic (US) processes, the development of environmentally friendly, effective, low-cost, and durable catalysts is needed to degrade pollutants. Here, ZnFe layered double hydroxide (LDH) was doped with vanadium (V) for the sonocatalytic degradation of a pesticide pymetrozine. The resulting catalyst had an average thickness of 25 nm, a specific surface area of 125.38 m(2)/g, and a bandgap value of 2.20 eV. In 90 min ultrasonic treatment, V-doped ZnFe LDH had 73% pymetrozine removal efficiency, which was 32% more than that of undoped ZnFe LDH. The US/V-doped ZnFe LDH process had a strong synergistic effect (synergy factor 7.17), which resulted in 57% and 68% greater efficiencies than the US alone and V-doped ZnFe LDH alone, respectively. The role of radical oxygen species was confirmed by carrying out radical trapping experiments using different scavengers and electron paramagnetic resonance analyses. Due to its high stability, the catalyst had good reuse potential with only an 8% performance reduction after 5 reuse cycles. Besides, the leaching of heavy metals was insignificant owing to the high integrity of the catalyst as confirmed by SEM and X-ray diffraction analysis. According to the GC-MS analysis, pymetrozine was first transformed into cyclic compounds then into aliphatic compounds such as animated products and carboxylic acids.
