Yazar "Bilici, Zeynep" seçeneğine göre listele

Listeleniyor 1 - 9 / 9
  • [ X ]
    Öğe
    Adsorption and Fenton oxidation of azo dyes by magnetite nanoparticles deposited on a glass substrate
    (Elsevier, 2019) Unal, Bahar Ozbey; Bilici, Zeynep; Ugur, Naz; Isik, Zelal; Harputlu, Ersan; Dizge, Nadir; Ocakoglu, Kasim
    Fenton oxidation is an efficient and useful method for wastewater treatment. To increase overall reaction efficiencies and inhibit environmental impacts, developing advanced catalysts are crucial in this matter. The main goal of this study was to investigate the catalytic activity of the magnetite (Fe2+Fe23+O42-, FeFe2O4, or Fe3O4) nanoparticles (NPs) coated borosilicate glass on the color removal of basic red 18 (BR18) and acid red 8 (AR88) azo dyes by adsorption and Fenton oxidation reaction. The efficiency of powder magnetite NPs was also tested to compare to magnetite NPs coated borosilicate glass. The effect of solution pH (2.5-9.0), catalyst loading (0.25-3.0 g/L), and dye concentration (0.1-0.3 mM) were tested to achieve maximum color removal efficiency using powder magnetite NPs. The color removal efficiencies were measured 44% at pH 9.0 and 76% at pH 3.5 for adsorption and Fenton oxidation of BR18 dye (0.1 mM). Moreover, the color removal efficiencies were measured 81% at pH 3.5 and 100% at pH 6.0 for adsorption and Fenton oxidation of AR88 dye (0.1 mM). The effect of hydrogen peroxide (H2O2) concentration (2.5-25 mM) was also optimized and 10 mM was found optimum H2O2 dosage for Fenton oxidation. However, magnetite NPs coated borosilicate glass enhanced maximum 77% and 82% color removal efficiencies for adsorption and Fenton oxidation of BR18 dye. Maximum 86% and 100% color removal efficiencies were obtained for adsorption and Fenton oxidation of AR88 dye. Stability of the powder magnetite NPs and magnetite NPs coated borosilicate glass catalyst was also investigated. The reusability of the catalyst showed that magnetite NPs coated borosilicate glass could be used at least 3 times without significant loss of activity compared to powder magnetite NPs for Fenton oxidation. The characterization of the catalyst was carried out using scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray powder diffraction (XRD), and zeta potential analyses before and after adsorption.
  • [ X ]
    Öğe
    Comparison of Cr(VI) adsorption and photocatalytic reduction efficiency using leonardite powder
    (Pergamon-Elsevier Science Ltd, 2022) Arslan, Hudaverdi; Eskikaya, Ozan; Bilici, Zeynep; Dizge, Nadir; Balakrishnan, Deepanraj
    It is very important to treat Cr(VI) from the aquatic environment due to its toxic and harmful effects. Conventional treatment methodology involving biological pathways is generally ineffective for wastewater containing Cr(VI). Therefore, it is necessary to develop environmentally friendly and economical methods to remove Cr(VI) from the aquatic environment. In this study, leonardite, which is a natural mineral that has no harmful effects on the environment, was used for Cr(VI) removal. Leonardite was used in both adsorption and photocatalytic treatment systems by only pulverizing without any chemical treatment. Characterizations of leonardite were obtained using X-ray fluorescence (XRF), fouirer transform infrared spektrofotometre (FTIR), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) analyses methods. The effects of solution pH (2-10), particle size (45-300 mu m), adsorbent dose (0.25-3 g/L), and initial concentration (10-30 mg/L) on Cr(VI) removal efficiency were investigated in both adsorption and photocatalytic experiments. In the adsorption process, a complete removal efficiency (100%) was obtained for 3 g/L of adsorbent dose with an initial Cr(VI) concentration of 10 mg/L at pH 2 for 2 h. In the photocatalytic process, 100% removal efficiency of Cr(VI) was obtained when four times less adsorbent dosage was used under the same conditions. In addition, the reuse of leonardite powder was also investigated under optimum experimental conditions. Leonardite powder preserved approximately 70% of its activity in the photocatalytic process while it lost 50% of its activity after 5 reuses in adsorption process.
  • [ X ]
    Öğe
    Fabrication and characterization of polyethersulfone membranes functionalized with zinc phthalocyanines embedding different substitute groups
    (Elsevier, 2021) Bilici, Zeynep; Ozay, Yasin; Yuzer, Abdulcelil; Ince, Mine; Ocakoglu, Kasim; Dizge, Nadir
    In this study, a novel polyethersulphone (PES) composite membrane incorporated with two different zinc phthalocyanines (ZnPc), tetra-iodo and octa(2,6-diphenylphenoxy), was fabricated through the phase inversion approach. Three different concentrations of zinc phthalocyanines (0.5, 1.0, and 2.0 wt.%) were blended into the PES membrane. The morphology and performance of the fabricated composite membranes were systematically studied by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) mapping, atomic force microscopy (AFM), porosity, water contact angle, antifouling, and rejection measurements. Hydrophobicity of the pristine membrane decreased from 79.67 degrees to 77.03 degrees and from 79.67 degrees to 67.57 degrees after blending of 2.0 wt.% tetra-iodo ZnPc (TI-ZnPc) and octa(2,6-diphenylphenoxy) ZnPc (DP-ZnPc), respectively. Furthermore, the porosity and mean pore radius decreased due to the introducing of ZnPc. Porosity of the pristine membrane decreased from 60.60 % to 44.96 % and 42.21 % after blending of TI-ZnPc and DP-ZnPc, respectively. Mean pore size of the pristine membrane decreased from 22.70 nm to 9.11 nm and 17.93 nm after blending of TIZnPc and DP-ZnPc, respectively. BSA filtration mostly affected the flux of pristine membrane and caused it to decrease from 133.5 to 87.1 L/m(2)h (relative flux reduction (RFR) of 34.7 %). RFR decreased up to 19.2 % and 17.3 % for TI-ZnPc 2.0 wt% and DP-ZnPc 2.0 wt% composite membranes. Pristine PES membrane rejected 45.8 % BSA. However, TI-ZnPc 2.0 wt% and DP-ZnPc 2.0 wt% composite membranes supplied 91.0 % and 70.6 % BSA rejections, respectively. In comparison to pristine PES membrane, the total resistance (R-t) values of the composite membranes decreased. The pristine PES membrane showed the lowest flux recovery ratio (FRR, 71.89 %) against BSA, while all-composite membranes showed promising antifouling properties. FRR increased up to 97.44 % and 89.06 % for TI-ZnPc 2.0 wt% and DP-ZnPc 2.0 wt% composite membranes, respectively. The pristine PES membrane showed the lowest FRR against activated sludge, while all composite membranes showed promising antifouling properties. Moreover, ZnPc-embedded PES composite membranes were irradiated with appropriate wavelengths of light in the presence of oxygen to generate reactive oxygen species to clean fouled membranes' surface. The results showed that photo-cleaning was very effective to recover membrane flux.
  • [ X ]
    Öğe
    Photocatalytic activity of calcined chicken eggshells for Safranin and Reactive Red 180 decolorization
    (Pergamon-Elsevier Science Ltd, 2022) Eskikaya, Ozan; Gun, Melis; Bouchareb, Raouf; Bilici, Zeynep; Dizge, Nadir; Ramaraj, Rameshprabu; Balakrishnan, Deepanraj
    One of the most important problems affecting the environment today is the inability to adequately treat wastewater containing dyes. Among of the many treatment processes used in the treatment of dye-containing wastewater, photocatalytic based wastewater treatment processes attract the attention of scientists as a new, economically feasible, and promising approach which has been in practice for a few decades. However, in order to use these processes in wider areas, cheap and effective catalysts are still being developed today. In this study, the photocatalytic activity of eggshell-CaO produced from waste chicken eggshells was investigated for decolorization of Safranin (Basic Red 2) and Reactive Red 180 (RR180) dyes. First, sintering process was applied to the waste chicken eggshells at different temperatures (300, 600, 900 degrees C) in order to observe CaO formation from the eggshells. Second, the parameters such as photocatalyst amount, pH, concentration of dyes, and reaction time were optimized on dye removal efficiency in photocatalytic experiments. The optimum conditions were performed under visible light and found to be 1 g/L of catalyst amount (sintered at 900 degrees C), original solution pH (6.80 for Safranin and 6.60 for RR180), and 5 mg/L of dye concentration. The photocatalytic removal efficiencies of Safranin and RR180 dyes were 100% and 97.90%, respectively, under the determined optimum experimental conditions. The adsorption efficiency of the dyes that could be realized during the photocatalytic experiment was measured as 20.99% and 9.99% for Safranin and RR180 dyes, respectively.
  • [ X ]
    Öğe
    Photocatalytic Decolorization of BR18 and RR180 Dyes by Semiconductor Diode Laser Using CuO for Wastewater Treatment
    (Springer Int Publ Ag, 2022) Polat, Baris; Bilici, Zeynep; Ozay, Yasin; Kucukkara, Ibrahim; Dizge, Nadir
    In this study, the use of copper(II) oxide (CuO) powders as catalyst and continuous wave (CW) multimode semiconductor diode laser (450 nm) was investigated for decolorization of Basic Red 18 (BR18) and Reactive Red 180 (RR180) aqueous dye solutions. The effects of laser power (0.5-2.5 W), pH of solution (2-10), CuO catalyst loading (0.25-1.50 g/L), H2O2 concentration (0.28-2.22 mg/L), initial dye concentration (20-60 mg/L) were studied systematically. Maximum removal efficiency was observed as 100% for RR180 and 94.34% for BR18 under the optimum conditions. Kinetic analysis of BR18 and RR180 dye decolorization reaction indicated that the overall rate order of the reaction was the pseudo first order. CuO demonstrated satisfactory reuse capability as the catalyst for five consecutive cycles without any decrease in its activity for RR180 dye.
  • [ X ]
    Öğe
    Polyethersulfone membranes modified with CZTS nanoparticles for protein and dye separation: Improvement of antifouling and self-cleaning performance
    (Elsevier, 2021) Ocakoglu, Kasim; Dizge, Nadir; Colak, Suleyman Gokhan; Ozay, Yasin; Bilici, Zeynep; Yalcin, M. Serkan; Ozdemir, Sadin
    In this study, a novel polyethersulphone (PES) nanocomposite membrane incorporated with copper zinc tin sulfide (Cu2ZnSnS4) nanoparticles (CZTS NPs) was prepared through the phase inversion method. First, the samples containing different copper and zinc ratios in CZTS stoichiometry were prepared and characterized. The effect of copper and zinc ratio changes were examined on the photocatalytic properties of both NPs and nanocomposite membranes. The photocatalytic effect was tested and BR18 dye was degraded at 88.0% efficiency when exposed to visible light for 180 min in the presence of CZTS1.0 NPs catalyst. The results also exhibited that CZTS NPs blended membrane showed good self-cleaning performance. Second, we investigated the antioxidant, DNA cleavage, and biofilm inhibition activities of CZTS NPs. The antimicrobial activities of CZTS NPs were tested against seven microbial strains. The highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and chelating activities were found as 81.80 +/- 1.75% and 72.19 +/- 4.63%, respectively. CZTS NPs exhibited double-strand DNA cleavage activity at 500 mg/L. They showed significant biofilm inhibition as 92.15 +/- 5.67% against Staphylococcus aureus. CZTS NPs displayed moderate antimicrobial effects against tested microorganisms. Third, CZTS NPs were blended in polyethersulphone (PES) membrane and the morphology as well as performance of the fabricated nanocomposite membranes were systematically investigated by SEM-EDX, porosity, water contact angle, antifouling, and rejection measurements. The water flux of resulting nanocomposite membranes was markedly enhanced due to the introducing of CZTS NPs. Meanwhile, the nanocomposite membranes demonstrated remarkable antifouling properties (flux recovery ratio similar to 94%) in contrast with the bare PES (flux recovery ratio similar to 51%) when BSA was filtrated. The high retention of BSA (100%) as well as high permeation flux (73.8 +/- 9.8 L/m(2)/h) of the CZTS2.00 wt% membrane demonstrated that the constructed nanocomposite membrane possessed the characteristics of a promising membrane for purification of proteins.
  • [ X ]
    Öğe
    Preparation of S-Scheme g-C3N4/ZnO Heterojunction Composite for Highly Efficient Photocatalytic Destruction of Refractory Organic Pollutant
    (Mdpi, 2023) Sert, Buse; Bilici, Zeynep; Ocakoglu, Kasim; Dizge, Nadir; Rad, Tannaz Sadeghi; Khataee, Alireza
    In this study, graphitic carbon nitride (g-C3N4)-based ZnO heterostructure was synthesized using a facile calcination method with urea and zinc nitrate hexahydrate as the initiators. According to the scanning electron microscopic (SEM) images, spherical ZnO particles can be seen along the g-C3N4 nanosheets. Additionally, the X-ray diffraction (XRD) analysis reveals the successful synthesis of the g-C3N4/ZnO. The photocatalytic activity of the synthesized catalyst was tested for the decolorization of crystal violet (CV) as an organic refractory contaminant. The impacts of ZnO molar ratio, catalyst amount, CV concentration, and H2O2 concentration on CV degradation efficiency were investigated. The obtained outcomes conveyed that the ZnO molar ratio in the g-C3N4 played a prominent role in the degradation efficiency, in which the degradation efficiency reached 95.9% in the presence of 0.05 mmol of ZnO and 0.10 g/L of the catalyst in 10 mg/L of CV through 120 min under UV irradiation. Bare g-C3N4 was also tested for dye decolorization, and a 76.4% dye removal efficiency was obtained. The g-C3N4/ZnO was also tested for adsorption, and a 32.3% adsorption efficiency was obtained. Photocatalysis, in comparison to adsorption, had a dominant role in the decolorization of CV. Lastly, the results depicted no significant decrement in the CV degradation efficiency in the presence of the g-C3N4/ZnO photocatalyst after five consecutive runs.
  • [ X ]
    Öğe
    Synthesis and characterization of composite catalysts comprised of ZnO/MoS2/rGO for photocatalytic decolorization of BR 18 dye
    (Elsevier, 2021) Ugur, Naz; Bilici, Zeynep; Ocakoglu, Kasim; Dizge, Nadir
    In recent years, photocatalysis upon semiconductor-based hybrid materials has received much attention for the improved environmental effects and energy applications. Many good semiconductors such as ZnO have large bandgaps and suffer from fast charge recombination which hinders photocatalytic activity. One possible strategy to overcome this problem is introducing a narrow bandgap co-catalyst. Within the context of this study, triple hybrid nanostructures comprised of ZnO nanorods and MoS2/rGO (MG) co-catalyst were synthesized and characterized by various analytical methods. Accordingly, 25ZnO/75MG and 75ZnO/25MG hybrid materials were synthesized for two different MG co-catalyst comprised of 0.5% (named as 25ZnO/75MG1) and 5% (named as 25ZnO/75MG2) graphene oxide. The photocatalytic activities of the heterostructures and pristine ZnO nanorods were evaluated by the degradation of BR 18 dye, a common water pollutant mainly from the textile industry. When introduced with the co-catalyst, 25ZnO/75MG1 heterostructures achieved 100% degradation for 180 min. Furthermore, when the GO amount in the co-catalyst was increased to 5%, fully degradation of the dye solution was realized by 25ZnO/75MG2 in the first 30 min. These results are indicative of a positive synergistic effect of MoS2-rGO co-catalyst. Also, it is shown that increasing the GO amount is an effective approach to accelerate charge separation and electron transport properties.
  • [ X ]
    Öğe
    Synthesis of mesoporous magnetic Fe3O4 nanoparticles with different pore sizes and investigation of dye adsorption capacities
    (Taylor & Francis Inc, 2024) Ulusal, Fatma; Bilici, Zeynep; Ozay, Yasin; Ozdemir, Nalan; Dizge, Nadir
    This study synthesized mesoporous magnetic Fe3O4 nanoparticles with two pore sizes. First, two different pore sizes of SiO2 were synthesized using polyethylene glycol with molecular weights of 6000 kDa and 35,000 kDa. Next, mesoporous SiO2 was used as a template, and Fe3O4 was coated with a precursor. Then, the silica present in mesoporous SiO2 was leached. The adsorption capacities of the prepared mesoporous magnetic Fe3O4-NPs were compared using an azo cationic dye, Basic Red 18. Parameters such as solution pH, adsorbent amount, and dye concentration were optimized in the adsorption experiments. Additionally, the reusability of Fe3O4-NPs was investigated. The optimum conditions for P6-Fe3O4-NPs were the original pH, 0.5 g/L dose, 50 ppm dye concentration, 60 min contact time, and 100% removal efficiency. For P35-Fe3O4-NPs, the optimal conditions were original pH, 0.75 g/L dose, 20 ppm dye concentration, and 60 min of contact time, with 100% removal efficiency. The second-order kinetic model and Langmuir isotherm were found to be suitable for describing the adsorption of both nanoparticles. Under the optimum conditions, complete dye removal efficiency was achieved for both nanomaterials. Furthermore, in the real wastewater, the adsorption experiment utilizing P6-Fe3O4-NPs yielded a 98% efficiency in color removal at 620 nm.