Browsing by Author "Sener, Lokman"

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Palladium (0) Nanoparticles Distributed on Lanthanum (Iii) Oxide as an Effective Catalyst for the Methanolysis of Hydrazine-Borane To Produce Hydrogen
(Tubitak Scientific & Technological Research Council Turkey, 2024) Ruzgar, Adem; Sener, Lokman; Karatas, Yasar; Gulcan, Mehmet
Pd (0) nanoparticles (NPs) distributed on lanthanum (III) oxide were ex situ generated from the reduction of Pd2+ ions using NaBH4 as reducing agent. The Pd/La2O3 displayed good catalytic activity in H2(g) releasing from the hydrazine-borane (HB) methanolysis reaction and it was identified by advanced techniques. Pd/La2O3 was found to be an active catalyst procuring three equiv. H2(g) per mole of HB. The results from TEM images represent the formation of Pd (0) NPs with an average particle size of 1.94 +/- 0.1 nm on the surface of La2O3. Moreover, Pd/La2O3 with various Pd loadings were prepared and tested as catalyst in the methanolysis reaction to find the optimum metal loading on La2O3 support. The highest H2 formation rate was achieved with 3.0 wt% Pd. Pd/La2O3 catalyst exhibited a turnover frequency (TOF) value of 24.4 mol H2 mol Pd-1 min-1 in the reaction conditions. Additionally, the effect of different catalyst concentrations and temperatures on the reaction kinetics for the methanolysis of HB catalyzed by Pd/La2O3.
Polyethersulfone Membranes Modified With 2D Mxene-CuO Nanocomposites for Protein Rejection and Investigation of Antimicrobial Properties
(Elsevier, 2025) Sener, Lokman; Alterkaoui, Aya; Ozdemir, Nihan Canan; Dizge, Nadir; Ozdemir, Sadin; Yalcin, M. Serkan; Gulcan, Mehmet
This study examines the effects of incorporating three MXene-CuO nanocomposites - Ti3C2Tx/CuO, V2CTx/CuO and Nb2CTx/CuO- into polyethersulfone (PES) membranes. The study aims to enhance the antifouling and permeation properties of PES membranes for bovine serum albumin (BSA) filtration. The experimental design involved adding each MXene-based composites to PES membranes at a fixed concentration of 1 %. These composite membranes were then evaluated using a dead-end filtration system. Their performance was compared to that of a control membrane composed of pure PES without any MXene-based nanocomposites. The results revealed significant improvements in BSA rejection efficiency. The pristine PES membrane achieved a rejection rate of 61.42 %, while the three composite membranes containing MXene-based nanocomposites showed complete BSA rejection, achieving 100 % removal efficiency. The synthesized MXene-based nanocomposites were also assessed for in vitro antioxidant, antidiabetic, DNA nuclease, antibiofilm and antimicrobial activities. V2CTx/ CuO exhibited 90.27 % antioxidant activity. Antidiabetic activity of V2CTx/CuO and Ti3C2Tx/CuO was achieved as 86.42 % and 96.46 %. All compounds caused single-strand DNA cleavage at 50 and 100 mg/L doses and double-strand cleavage caused at 200 mg/L dose. The low MIC values obtained revealed that the compounds presented effective antibacterial properties. V2CTx/CuO, Nb2CTx/CuO and Ti3C2Tx/CuO was also displayed influential microbial growth inhibition as 82.79 %, 98.62 % and 100 %, respectively. The highest antibiofilm activity against S. aureus and P. aeruginosa for V2CTx/CuO, Nb2CTx/CuO and Ti3C2Tx/CuO was 71.25 % and 56.85 %; 87.91 % and 69.16 %; and 92.55 % and 84.22 %, respectively. It was also found that the antimicrobial surface of PES membrane doped with 1 % V2CTx/CuO, Nb2CTx/CuO and Ti3C2Tx/CuO displayed 72.58 %, 84.62 %, and 95.49 % antibacterial ability, respectively.
Synthesis, Characterization, and Determination of the Catalytic Roles of Tungsten (VI) Oxide-Supported Pd (0) Nanoparticles in the Reduction of Nitroaromatic Pollutants
(Elsevier Science SA, 2025) Ruzgar, Adem; Karatas, Yasar; Yurderi, Mehmet; Sener, Lokman; Gulcan, Mehmet; Zahmakiran, Mehmet
One of the most important approaches for industrial and environmental catalytic applications is to develop a promising, simple, and effective method. Toxic organic pollutants in wastewater, such as nitroaromatic contaminants, have become a global issue, threatening aquatic life and obstructing essential elements required for the survival of living organisms. In this study, a palladium pre-catalyst supported on tungsten (VI) oxide (Pd2+/ WO3) was prepared with a 2 % metal loading using a simple and conventional wet impregnation method. The efficiency of this pre-catalyst was investigated for the reduction of nitroaromatic pollutants (2-nitrophenol (2 NP), 4-nitrophenol (4-NP), and 2,4-dinitrophenol (2,4-DNP)) into their corresponding aminophenol compounds in the presence of an excess amount of NaBH4 as the reducing agent. Characterization techniques such as ICPOES, XRD, SEM, SEM/EDX, TEM, and XPS analysis revealed that Pd (0) nanoparticles were well-dispersed on the WO3 support, with an average particle size of 2.2 +/- 0.1 nm. The catalytic activities of Pd (0) nanoparticles for the reduction of nitroaromatic pollutants to aminophenols in the presence of NaBH4 were determined in terms of initial TOF, calculated as 127.2 min(-1) for 2-NP, 109.4 min(-1) for 4-NP, and 353.1 min(-1) for 2,4-DNP. The results demonstrated that the Pd/WO3 nanocatalyst exhibited excellent catalytic efficiency and stability (>85 %) even after five catalytic cycles in the reduction of nitroaromatic pollutants. Considering both the simple preparation process and the effective catalytic reduction of nitroaromatic pollutants, this study presents a great opportunity for the practical application of the Pd/WO3 nanocatalyst in wastewater treatment.