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- MakaleAçık Erişim2019Scopus SJRQ3Study of the bioaccumulation of UO2 2+ onto the green microalgae botryococcus braunii using response surface methodology
Celik, Fatih; Aslani, Mahmoud Ali Asker; Can, Safak Seyhaneyildiz
The bioaccumulation of UO2 2+ (uranyl ion) was investigated by using dry biomass of Botryococcus braunii. Experiments were conducted based on a rotatable central composite design (CCD) and analyzed using response surface methodology (RSM), which was used to optimize the bioaccumulation process. In this goal, the effects of parameters such as initial uranium (VI) concentration, pH, temperature and contact time were studied. The optimum conditions for maximum removal (87%) of UO2 2+ from an aqueous solution were as follows: initial uranium (VI) concentration (55 mg/l), pH (3.6), temperature (46°C) and contact time (74 min). Langmuir and Freundlich isotherms and also thermodynamic parameters like Enthalpy (∆H°), Entropy (∆S°), standard Gibbs free energy (∆G°) were investigated, as well.
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İncele - MakaleYalnız künye2019Scopus SJRQ2Biosynthesis of gold nanoparticles using marine bacteria and Box–Behnken design optimization
Camas, Mustafa; Celik, Fatih; Sazak Camas, Anil; Ozalp, Hasan Baris
Gold nanoparticles are exciting materials because of their potential applications in optics, electronics, biomedical, and pharmaceutical fields. In recent years, environmentally friendly, low-cost biosynthesis methods with bio-applicable features have continued to be developed for the synthesis of gold nanoparticles. In the present study, an actinobacterial strain was isolated from the Petrosia ficiformis (Poiret 1798) sponge, which was collected from a marine environment, and the gold nanoparticle synthesis was performed for the first time from the bacteria type belonging to the Citricoccus genus. The synthesis conditions were optimized using the Box–Behnken experimental design, with a statistical method that included three independent variables (temperature, time, and mixture ratio) to affect the synthesis at three levels (+1, 0, and −1). Accordingly, the conditions proposed for the biosynthesis of gold nanoparticles at the maximum optical density values that are specific for the Citricoccus sp. K1D109 strain were estimated as 35°C temperature, 24 h, and 1/5 mixture ratio (cell-free extract/HAuCl4 · 3H2O). When recommended conditions were applied, it was determined that the maximum absorbance of the synthesized gold nanoparticles is 1.258 at 545 nm, and their sizes are in the range of 25–65 nm, according to transmission electron microscopy (TEM) data.
AtıfScopus33WoS30OpenAlex34İncele - MakaleYalnız künye2018Scopus SJRQ2Microbial Sorption of Uranium Using Amycolatopsis sp. K47 Isolated from Uranium Deposits
Celik, Fatih; Camas, Mustafa; Kyeremeh, Kwaku; Sazak Camas, Anil
The increasing contamination of soils, sediments, and water with heavy metals through natural and industrial processes is a worldwide problem. Mining processes produce tons of material contaminated with radionuclides such as U and different heavy metals such as Cd, Ni, and Pb. U(VI) adsorbs strongly on bacteria, exhibiting pH-dependent adsorption behavior that is caused by a range of uranyl surface complexes on bacteria cell walls. The Amycolatopsis sp. K47 was isolated from Manisa Koprubasi Kasar open-cast uranium mine and identified for the first time. Using the batch adsorption method, the biosorption potential of this microbe was investigated by studying the effects of changes in pH (1–10), biomass dose (0.1–5 g/l), initial uranium metal concentration (5–200 mg/l), contact time (5–180 min), and temperature (20–60 °C). Interpretation of FTIR data obtained for both the uranium loaded and unloaded Amycolatopsis sp. K47 biomass showed the presence of carboxylic acid, hydroxyl, and amide functional groups that could interact with uranium ions. Scanning electron microscopy images demonstrated that uranium was intensely adsorbed on the microbial biomass surface. The sorption isotherms were investigated by analysis of the Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) models. The Langmuir isotherm model was found to show the best fit for the experimental data obtained. Furthermore, thermodynamic parameters, such as ΔH°, ΔS°, and ΔG°, were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. The optimal experimental conditions were determined to be pH = 4, C0 = 40 ppm, t = 150 min, temp. = 40 °C, and abs. dose = 1 g/l, and the corresponding U(VI) removal efficiency was about 97 ± 2%.
AtıfScopus16WoS14OpenAlex15İncele - MakaleAçık Erişim2016Scopus SJRQ3Uranium (VI) Biosorption on Marine Sponge, Sarcotragus foetidus (Schmidt, 1862) and Its Statistical Investigation Using Central Composite Design
Celik, Fatih; Camas, Mustafa; Camas, Anil Sazak; Ozalp, Hasan Baris
The biosorption of heavy metals, radionuclides, uranium and thorium for the recovery or removal from aqueous systems using various micro-organisms and biological substances has been investigated by several groups of workers. In this paper, the uptake of uranium (VI) from aqueous systems by a marine sponge, Sarcotragus foetidus (Schmidt, 1862) has been investigated. S. foetidus samples were collected from Babakale/Ayvacik/Canakkale in Turkey. Uranium (VI) uptake experiments were carried out by the batch technique. The affecting parameters were analyzed using Central Composite Design (CCD) as the experimental method. Four independent variables such-pH, temperature, contact time, and initial uranium concentration were selected for this study. The influences of initial pH, contact time, and initial uranium concentration on the biosorption process were considered statistically significant as main effects. On the other hand, interaction effects of pH and contact time, as well as pH and initial uranium concentration, were considered as significant parameters on the biosorption process. The optimum condition of biosorption process was found to be at initial pH: 4, temperature: 35 degrees C, initial uranium concentration: 20 mg/L, and contact time: 31 minutes. At these conditions, the biosorption yield of uranium (VI) ions was obtained to be 93.29 +/- 2%.
AtıfWoS2OpenAlex1İncele - MakaleAçık Erişim2016Scopus SJRQ2Toxicity of Engineered Nickel Oxide and Cobalt Oxide Nanoparticles to Artemia salina in Seawater
Ates, Mehmet; Demir, Veysel; Arslan, Zikri; Camas, Mustafa; Celik, Fatih
In this study, the effects of exposure to engineered nickel oxide (NiO 40-60 nm) and cobalt oxide (CoO < 100 nm) nanoparticles (NP) were investigated on Artemia salina. Aggregation and stability of the aqueous NP suspensions were characterized by DLS and TEM. Acute exposure was conducted on nauplii (larvae) in seawater in a concentration range from 0.2 to 50 mg/L NPs for 24 h (short term) and 96 h (long term). The hydrodynamic diameters of NiO and CoO NPs in exposure medium were larger than those estimated by TEM. Accumulation rate of NiO NPs were found to be four times higher than that of CoO NPs under the same experimental conditions. Examinations under phase contrast microscope showed that the nanoparticles accumulated in the intestine of Artemia, which increased with increasing exposure concentration. Differences were observed in the extent of dissolution of the NPs in the seawater. The CoO NPs dissolved significantly while NiO NPs were relatively more stable. Oxidative stress induced by the NP suspensions was measured by malondialdehyde assay. Suspensions of NiO NPs caused higher oxidative stress on nauplii than those of CoO NPs. The results imply that CoO and NiO NPs exhibit toxicity on Artemia (e. g., zooplankton) that is an important source of food in aquatic food chain.
AtıfWoS59OpenAlex71İncele - MakaleAçık Erişim2015Scopus SJRQ2Influence of Alpha and Gamma-Iron Oxide Nanoparticles on Marine Microalgae Species
Demir, Veysel; Ates, Mehmet; Arslan, Zikri; Camas, Mustafa; Celik, Fatih; Bogatu, Corneliu; Can, Safak Seyhaneyildiz
The effects of alpha-iron oxide (alpha-Fe2O3) and gamma-iron oxide (gamma-Fe2O3) nanoparticles (NPs) on marine microalgae species (Nannochloropsis sp. and Isochrysis sp.) were investigated in this study. Both Fe2O3 NPs covered the surface of algae with the agglomerates of the nanoparticles. This form of physical NP toxicity significantly decreased the sizes of phytoplankton. Both NPs were toxic to the tested algal species, while alpha-Fe2O3 showed less toxicity than gamma-Fe2O3 NPs for both algal species. A comparative analysis of growth data of the two algal species treated with alpha-Fe2O3 or gamma-Fe2O3 NPs revealed that Isochrysis sp. are more sensitive than Nannochloropsis sp. Toxicity of these widely used NPs to primary producers forming the base of the food chain in aquatic environments might result in widespread adverse effects on aquatic environmental health.
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