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Öğe ADSORPTION OF CRYSTAL VIOLET FROM AQUEOUS SOLUTION ON ACTIVATED CARBON DERIVED FROM GOLBASI LIGNITE(Oficyna Wydawnicza Politechniki Wroclawskiej, 2012) Depci, Tolga; Kul, Ali Riza; Onal, Yunus; Disli, Erkan; Alkan, Salih; Turkmenoglu, Z. FundaActivated carbon (AC) was obtained from lignite of the local resource, Golbasi - Adiyaman (Turkey) by chemical activation. The Golbasi lignite was chosen as the precursor for its availability and low cost. The BET surface area of the activated carbon was found 921 m2/g. The AC was used as an adsorbent for Crystal Violet (CV) in aqueous solution. The adsorption properties of CV onto the activated carbon are discussed in terms of the adsorption isotherms (Langmuir and Freundlich) and the kinetic models (pseudo-first-order, pseudo-second-order and intraparticle diffusion model). It was shown that the experimental results best fitted by the Langmuir model, and the second-order kinetic equation. The thermodynamic parameters show that the adsorption process is endothermic. The experimental results point out that the obtained activated carbon is a viable candidate for sorbent removing CV from aqueous solutions.Öğe Adsorption of Crystal Violet on Activated Carbon Prepared from Coal Flotation Concentrate(Iop Publishing Ltd, 2016) Aydogmus, Ramazan; Depci, Tolga; Sarikaya, Musa; Kul, Ali Riza; Onal, YunusThe objective of this study is firstly to investigate the floatability properties of Zilan-Van coal after microwave irradiation and secondly to produce activated carbon from flotation concentrate in order to remove Crystal Violet (CV) from waste water. The flotation experiments showed that microwave heating at 0.9 kW power level for 60 sec exposure time enhanced the hydrophobicity and increased the flotation yield. The activated carbon with remarkable surface area (696 m(2)/g) was produced from the flotation concentrate and used to adsorb CV from aqueous solution in a batch reactor at different temperature. The adsorption properties of CV onto the activated carbon are discussed in terms of the adsorption isotherms (Langmuir and Freundlich) and found that the experimental results best fitted by the Langmuir model.Öğe Apricot stone activated carbons adsorption of cyanide as revealed from computational chemistry analysis and experimental study(Elsevier, 2014) Depci, Tolga; Onal, Yunus; Prisbrey, Keith A.This study utilizes computational chemistry analysis (molecular dynamics and ab initio simulations) in order to understand the nature of adsorption of cyanide from aqueous solution by activated carbon and to compare the adsorption mechanism between activated and magnetic activated carbons. In addition, real adsorption mechanism of cyanide was investigated by laboratory adsorption tests using apricot plain (AAC) and magnetic activated (AMAC) carbon. The morphology, structure and property of AAC and AMAC were determined by BET, XRD, XRF and magnetometer, respectively. The simulation results reveal that the adsorption mechanism of cyanide on AAC and AMAC is nearly similar. Modifying the graphite surface with magnetite to mimic magnetic activated carbon does not have any significant influence on cyanide adsorption. The experimental results also support this fact to some extent as the maximum monolayer adsorption capacities of AAC and AMAC are very close with each other, 61.56 and 59.71 mg/g, respectively. Although iron impregnation does not significantly affect the removal of cyanide, considering the magnetic property of AMAC which can be removed easily by a magnetic separator, AMAC may be better sorbet than AAC and commercial activated carbon. (C) 2014 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.Öğe ?-carotene rejection mechanism from organic medium by using activated carbon produced from waste biomass apricot(Taylor & Francis Inc, 2017) Akmil-Basar, Canan; Durmaz, Gokhan; Karabulut, Ihsan; Onal, YunusThe present paper deals with the study of adsorption of beta-carotene in tetrahydrofuran solution on activated carbon. Activated carbon was prepared from apricot waste, which is a by-product of apricot processing by means of chemical activation with ZnCl2. BET surface area of activated carbon was measured to be 1060m(2) g(-1). The effect of adsorption time, percentage of activated carbon in beta-carotene solution, and beta-carotene concentration on adsorption efficiency was also determined. Results were analyzed by the Langmiur, Freundlich, Dubinin-Redushkevich (D-R), Temkin, Frumkin, Harkins-Jura, Halse, Henderson, and Henry isotherms with linearized correlation coefficient. The characteristic parameters for each isotherm have also been determined. The kinetics of beta-carotene adsorption has been discussed by the pseudo-first-order model, the pseudo-second-order model, the Elovich equation, the intraparticle diffusion model, the Bangham equation, and the modified Freundlich equation. Three error analysis methods of residual mean square error (RMSE), chi-square statistic ((2)), and the average percentage error (% APE) have been used.Öğe CHARACTERISTIC PROPERTIES OF ADSORBED CATALASE ONTO ACTIVATED CARBON BASED ADIYAMAN LIGNITE(Parlar Scientific Publications (P S P), 2011) Depci, Tolga; Alkan, Salih; Kul, Ali Riza; Onal, Yunus; Alacabey, Ihsan; Disli, ErkanCatalase is one of the most common and important enzymes in biological systems. However, its purification process has some difficulties and it can be easily decomposed in aqueous or nonaqueous solutions. Therefore, a catalase should be adsorbed on solid materials to reduce its inactivation and to increase its economic value. Activated carbon which was obtained from Turkish low-rank coal (Golbasi-Adiyaman) by chemical activation was used as a solid carrier to adsorb catalase for the first time in this research. The pore structure of the activated carbon was determined by A Tri Star 3000 (Micromeritics, USA) surface analyzer and scanning electron microscope. In order to determine adsorption properties of catalase, ionic strength effect, temperature-activity, pH-activity, storage stability and operational stability of the activated carbon were investigated. The kinetic and thermodynamic mechanisms of adsorbed enzyme were also studied. The experimental results pointed out that the obtained activated carbon is a viable candidate for an alternative solid carrier for catalase and it may be a promising material for various biotechnological applications.Öğe Competitive adsorption of lead and zinc from aqueous solution on activated carbon prepared from Van apple pulp: Study in single- and multi-solute systems(Elsevier Science Sa, 2012) Depci, Tolga; Kul, Ali Riza; Onal, YunusThe potential of activated carbon (VAAC) prepared from local agricultural waste, apple pulp, as an alternative low-cost adsorbent was investigated for the removal of lead and zinc from single- and multi metal aqueous solution. VAAC was produced with a reasonable yield, 43% and has remarkable surface area (1067.01 m(2)/g) with a well-developed pore structure. To determine the adsorption process and properties, the effects of various operating parameters, pH of the solutions (2-6), adsorbent dosage (0.01-0.2 g), initial concentration of metal ions (25-40 mg/L), contact time (3-120 min) and temperature (298-308 K) were investigated in a batch adsorption technique. The adsorption isotherm data were better fitted by Langmuir model. The pseudo second-order model was found more applicable to describe the kinetic of system in both the single- and multi-solute system. The adsorption capacities of heavy metals decrease in the order of Pb(II) (15.96 mg/g) < Pb (Pb + Zn) (13.23 mg/g) < Zn(II) (11.72 mg/g) < Zn (Pb + Zn) (7.54 mg/g) at 298 K. Although individual metal ions adsorption decreases in multi-system. the more metal ions are adsorbed (20.77 mg/g). The intraparticle diffusion model, external mass transfer coefficient, film and pore diffusion coefficient at different temperatures were also evaluated to investigate the adsorption mechanisms of both systems. The adsorption was mainly controlled film diffusion process at all operating temperatures and concentrations. The thermodynamic parameters indicate that the adsorption process is endothermic, feasible and thermodynamically favored. (C) 2012 Elsevier B.V. All rights reserved.Öğe Conversion of grape industrial processing waste to activated carbon sorbent and its performance in cationic and anionic dyes adsorption(Elsevier Sci Ltd, 2015) Saygili, Hasan; Guzel, Fuat; Onal, YunusGrape processing industry waste was used as a novel precursor for the production of a low-cost activated carbon with zinc chloride chemical activation. The effects of the production variables, such as impregnation ratio, activation temperature and activation time on the some textural properties were investigated. The optimal activated carbon which had the highest surface area and pore volume was obtained by these conditions as follows: 6:1 impregnation ratio, 600 degrees C activation temperature and 60 min activation time. The optimum conditions resulted in an activated carbon with a carbon content of 81.76% and a yield of 44.13%, while the surface area of 1455 m(2)/g, with the total pore volume of 2.318 cm(3)/g, mesoporosity of 94.61% and average pore diameter of 6.81 nm. These results showed that the grape wastes seemed to be an alternative precursor for the commercial activated carbon productions. The adsorptive property was tested using Methylene blue and Metanil yellow dyes. The adsorption behaviors for both dyes were well described by the Langmuir isotherm model, showing a monolayer adsorption capacity of 417 mg/g and 386 mg/g for Methylene blue and Metanil yellow, respectively. This study demonstrated that produced optimal activated carbon could be employed as an efficient cleaner to compare with the commercial ones for the removal cationic and anionic dyes from wastewater. (C) 2015 Elsevier Ltd. All rights reserved.Öğe THE EFFECT OF USING ACTIVATED CARBON OBTAINED FROM SEWAGE SLUDGE AS A FUEL ADDITIVE ON ENGINE PERFORMANCE AND EMISSIONS(Vinca Inst Nuclear Sci, 2023) Bilgin, Serhat; Onal, Yunus; Akansu, Selahaddin Orhan; Ilhak, Mehmet IlhanThe increasing need for clean water depending on the world's population has accelerated efforts to re-evaluate the use of water. This has led to the spread of wastewater treatment plants (WWTP). Sewage sludge (SS), which is the waste of WWTP, is increasing due to the increase in the number of plants. As a result, the disposal and evaluation of SS, which is waste, has accelerated. In this study, researches were carried out on different usage areas of SS, which is WWTP waste. The SS was first dried. After the drying process, the SS was subjected to physical and chemical activation processes and turned into activated carbon. Activated carbons were obtained at different operating temperatures. The FT-IR, XRD, ICP-MS, TG-DTA, CHNS, SEM-EDX analyzes were performed for the obtained activated carbons. According to the results of the analysis, the selected activated carbons were mixed with diesel fuel at 50 ppm and 100 ppm ratios. The effects of fuel mixtures prepared with diesel fuel in terms of engine performance, combustion and emissions are investigated. Engine performance and exhaust emission measurements were made in a 6-cylinder Diesel engine at a constant speed of 600 rpm and under five different loads (0 Nm, 50 Nm, 100 Nm, 150 Nm, and 200 Nm). Emission values were measured as CO, HC, CO2, O-2, and NOx and comparative assessments were made. In this study, the positive effects of SS-derived activated carbons on the engine were determined by using it as a diesel fuel additive.Öğe Equilibrium, kinetic and thermodynamic adsorptions of the environmental pollutant tannic acid onto activated carbon(Elsevier Science Bv, 2010) Sarici-Ozdemir, Cigdem; Onal, YunusPolymeric waste, which is the main waste from textural industry in Turkey, was used as the raw material for the preparation of activated carbon by chemical activation with KOH. The pore properties, such as BET surface area, pore volume, pore-size distribution, and pore diameter, of the activated carbon were characterized by the t-plot based on the N-2-adsorption isotherm. The BET surface area of activated carbon (SK) was determined as 2390 m(2)/g. Activated carbon has been used for the removal of tannic acid from aqueous solutions. Adsorption experiments were carried out as a function of initial tannic acid concentration, contact time, and pH. Adsorption data were modeled using the Langmuir and Freundlich adsorption isotherms. The kinetic studies showed that the adsorption followed a pseudo second-order reaction. The intraparticle diffusion rate constant, external mass transfer coefficient, film and pore diffusion coefficients at various temperatures were evaluated. The thermodynamic parameters, such as Delta G(0), Delta S-0, and Delta H-0, were calculated. The thermodynamics of tannic acid-SK system indicates endothermic process. (c) 2009 Elsevier B.V. All rights reserved.Öğe Error Anlaysis Studies of Dye Adsorption onto Activated Carbon from Aqueous Solutions(Taylor & Francis Inc, 2014) Sarici-Ozdemir, Cigdem; Onal, YunusAdsorption of tartrazine and methylene blue from aqueous solution onto activated carbon has been investigated. Experimental datas obtained from dye adsorption have been studied by five two-parameter (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, and Frumkin), five three-parameter (Redlich-Peterson, Sips, Toth, Radke-Prausnitz, Koble-Corrigan) isotherm models. In this study, eight nonlinear error functions (sum squares errors, hybrid fractional error function, Marquardt's percent standard deviation, average relative error, sum of absolute error, the coefficient of determination, nonlinear chi-square test, and standard deviation of relative errors) were examined for isotherm equations. In order to clarify the adsorption kinetics fit of pseudo-first order and pseudo-second order kinetic models were used. The best fitting isotherm model was the Radke-Prausnitz and kinetics model was pseudo-second order for two dyes. Adsorption experiment showed that the maximum capacity of activated carbon's for methylene blue and tartrazine were 28.571 and 18.182mg.g(-1), respectively.Öğe Evaluation of optimum carbonization conditions of the blended domestic polymeric waste, biomass and lignite in the presence of catalyst by Taguchi and ANOVA optimization analysis(Elsevier, 2022) Basar, Canan Akmil; Korkmaz, Aydan Aksogan; Onal, Yunus; Utku, TugbaIn this work, the effects of blending mass ratio, pyrolysis temperature, pyrolysis time, heating rate, and amount of catalyst on the pyrolysis of the blended lignite (EL), pistachio shell (PS) and domestic wastes (DW) were investigated. The influence of experimental parameters on the char, liquid and gas efficiency was statistically evaluated by the Taguchi method and ANOVA analysis. The optimum experimental conditions is a1b1c2d1e3, a3b1c1d1e2, a2b3c2d3e2 for liquid efficiency, char efficiency and gas efficiency respectively. The amount of catalyst was found to be the most effective parameter for solid efficiency and the mass ratio for both liquid and gas efficiency. The char, liquid and gas efficiencys estimated by the Taguchi method under optimum experimental conditions are 39.58%, 18.5% and 47.04%, respectively. The char efficiency of 42.54%, liquid efficiency of 19.78% and gas efficiency of 49.83% were determined under optimum experimental conditions obtained by the Taguchi method. Analysis of Variance (ANOVA) was also used to determine the mean response magnitudes of each controllable process parameter. ANOVA analysis results support the results found by the Taguchi method. In the carbonization process, FTIR, XRD and SEM analyzes were performed to determine the structural change of the solid product depending on the temperature.Öğe Genotoxic effects of sulfur dioxide in human lymphocytes(Sage Publications Inc, 2014) Uren, Nihal; Yuksel, Sengul; Onal, YunusSulfur dioxide (SO2), which is used as food preservative in apricot sulfurization and several fabricated foods, is a common air pollutant. The aim of this study was to reveal the possible genotoxic effects of SO2 using in vitro human lymphocytes. The different endpoints of genotoxicity: sister chromatid exchange (SCE), micronuclei (MN) tests and cell growth kinetics such as mitotic index (MI) and replication index (RI) were studied. The cells were treated with 0.1, 0.5 and 1.0 ppm concentrations of SO2. It was shown that SO2 caused significant increases in the frequency of SCE and MN in the middle and high dosage groups and also induced mitotic delays and decreased MI and RI. In conclusion, the results have confirmed that SO2 has potent mutagenicity and it can cause genetic damage leading to a malignancy.Öğe Graphene quantum dots prepared from dried lemon leaves and microcrystalline mosaic structure(Wiley, 2021) Kir, Sifa; Dehri, Ilyas; Onal, Yunus; Esen, RamazanThe aim of this study is to obtain graphene quantum dots (GQDs) by using Citrus limonum leaves grown in Adana Province, Mediterranean region. Thus, dried Citrus limonum leaves were subjected to carbonization at temperatures of 200, 275, 350, 425 and 500 degrees C and 90, 180, and 270 min respectively at each temperature. Characterization of the material obtained at the end of the process was determined by using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), fluorescence spectroscopy, elemental analyzer, scanning electron microscopy (SEM), ultraviolet (UV)-visible, UV-A and UV-C lamps. It was determined that the samples obtained in the carbonization process carried out at 350 and 425 degrees C for 3 h made blue colored fluorescence. The results of the experiments completed for characterization analysis verified the GQDs and mosaic crystal structure compared to the literature. It was observed that the GQDs obtained at 350 degrees C for 3 h had maximum fluorescence properties. Radical changes at the sample matrix was observed when carbonization temperature changed from 350 degrees C to 425 degrees C.Öğe Heavy metal pollution and physiological changes in the leaves of some shrub, palm and tree species in urban areas of Adana, Turkey(Taylor & Francis Ltd, 2012) Doganlar, Zeynep Banu; Doganlar, Oguzhan; Erdogan, Selim; Onal, YunusThe effects of anthropogenic pollution on metal accumulation and some physiological parameters were investigated in plant leaves in the Adana, located in the Mediterranean region of Turkey. Washingtonia filifera L., Eucalyptus camaldulensis L., Phoenix dactylifera L., Platanus orientalis L., Citrus aurantium L., Nerium oleander L. and Schinus molle L. plants were collected from four different locations having different pollution levels in Adana. Concentrations of metals (Al, B, Ba, Fe, Pb, Sr and Zn), pigment (chloropyhll and carotenoid), lipid peroxidation product (malondialdehyde), and peroxidase (POD) enzyme activity were determined in the leaf tissues of these plants. Nerium oleander was determined to be a suitable biomonitor for heavy metal accumulation from anthropogenic and traffic activities in Adana. It was also determined that S. molle accumulated more Cu, Pb and Zn than all the other plant species and that metal accumulation did not cause a significant increase in pigment content of this plant. Our results indicate that POD enzyme activities in P. orientalis (Sr and Zn), C. aurantium (Ba) and N. oleander (Cu and Pb) can be used as suitable indicators for heavy metal stress. Additionally, we propose that S. molle can be used as a biomonitor for Pb, Cu and Zn, while N.oleander can be used as a biomonitor for Fe, Al, and Ba.Öğe Identification of chrysotile in local soil at Beypinari village (Sivas-Turkey) regarding mine and health issue(Springer India, 2016) Onal, Yunus; Depci, Tolga; Onal, Ayten; Onal, Ali; Uner, TijenAsbestos is dangerous for health and is forbidden to use in Turkey, but villagers who live in rural eastern part still use it especially for their home for insulation purposes and even as a substitute for baby powder. Therefore, geological and chemical properties of this type of soil, which is near the settlement, should be characterized and identified from the point of view of health. Beypinari asbestos deposits are located at Beypinari village, about 90 km southeast of Sivas, Turkey within Central Anatolian Ophiolites. Therefore, in the present study, the existence of chrysotile in Beypinari asbestos deposit were characterized and identified by mineralogical analysis and by major, trace, REE analysis. The results show that the samples contain different amount of calcite mineral, the main mineral being chrysotile.Öğe Immobilization of ?-Amylase onto Quantum Dots Prepared from Hypericum perforatum L. Flowers and Hypericum capitatum Seeds: Its Physicochemical and Biochemical Characterization(Springer/Plenum Publishers, 2023) Acari, Idil Karaca; Dik, Gamze; Bakar, Busra; Ulu, Ahmet; Onal, Yunus; Ates, BurhanEnzyme immobilization is an effective way to increase the catalytic activity and stability of the alpha-amylase (Amy) enzyme for industrial uses. For this purpose, carbon and graphene quantum dot (QDs) structures were prepared from Hypericum perforatum L. flowers (QD-1), and Hypericum capitatum seeds (QD-2) obtained from an herbalist in Hatay province of Turkey. Structural and morphological characterization of the prepared QDs and QDs/Amy were carried out by Fourier transform infrared spectrophotometer (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray (EDX). Meanwhile, biochemical characterizations such as optimum pH and temperature, kinetic parameters, effects of metal ions, organic solvents, and trypsin digestion on enzyme activity were performed and compared with free Amy. The Amy enzyme was immobilized with an activity efficiency of 71.15% for QD-1/Amy, and 81.51% for QD-2/Amy under optimal conditions. The difference in activity efficiency between QD-1/Amy and QD-2/Amy was likely due to a change in the surface porosity of QDs structures. While the optimal pH value of all three forms of Amy was recorded as 6.0, their optimal temperature was found to be 40 degrees C. The activation energy (E-a) of the free Amy was found to be 4.81 kJ/mol, while it was 9.61 kJ/mol, and 3.20 kJ/mol for QD-1/Amy, and QD-2/Amy, respectively. K-m values were calculated as 1.18, 1.57, and 1.35 mg/mL for free Amy, QD-1/Amy, and QD-2/Amy, respectively, and V-max values were calculated as 37.52, 37.60, and 39.93 mu mol/min, respectively. Kinetic data revealed that the immobilized enzymes had lower substrate affinity compared to the free Amy. Besides, the QD-1/Amy and QD-2/Amy exhibited more stability than free Amy against metal ions, organic solvents as well as trypsin digestion due to the increment in conformational rigidity caused by changes in the secondary structures of the immobilized enzyme. For instance, after incubation with trypsin for 120 min, free Amy, QD-1/Amy, and QD-2/Amy retained approximately 20%, 35%, and 26% of initial activities, respectively. Finally, it can be proposed that the prepared carriers in this work may a useful to produce stable and active immobilized Amy to be used in industrial applications.Öğe INVESTIGATING REMOVAL OF TRIMETHYLXANTHINE BY ACTIVATED CARBON PREPARED FROM PET WASTE(Parlar Scientific Publications (P S P), 2012) Sarici-Ozdemir, Cigdem; Onal, YunusActivated carbon (BK) has been prepared from polymeric wastes by chemical activation with KOH. Adsorption of trimethylxanthine onto BK was investigated with variations of pH, contact time, trimethylxanthine concentration, and temperature. The results were analyzed by the Langmuir and Freundlich equations. Adsorption of trimethylxanthine (caffeine) onto BK follows the Langmuir isotherm model. The kinetics of trimethylxanthine adsorption has been discussed using three kinetic models, i. e., the pseudo first-order, the pseudo second-order, and the intraparticle diffusion models. The kinetic studies showed that the adsorption followed a pseudo second-order reaction. The intraparticle diffusion rate constant, the external mass transfer coefficient, film and pore diffusion coefficients at various temperatures were evaluated. The thermodynamic parameters, such as Delta G degrees, Delta S degrees, and Delta H degrees, have been calculated. The thermodynamics of the trimethylxanthine -BK system indicated an endothermic process.Öğe Investigation of electrochemical performance of Na-ion batteries by hard carbon anodes produced by biomass of Prunusarmeniaca seeds(Springer, 2023) Oktay, Zeynep Melek; Onal, Yunus; Depci, Tolga; Altundag, Sebahat; Altin, Serdar; Yasar, Sedat; Altin, EmineHard carbon is successfully fabricated using biomass of Prunusarmeniaca seed shells, and its structural properties are examined by different spectroscopic techniques. For using as an anode electrode in Na-ion batteries, the material is subjected to further pyrolysis at varying temperatures for achieving the necessary levels of conductivity and surface area which are important features for electrode materials. Distinguish properties of the hard carbon in the XRD study appeared as broad peaks at 2 & theta; = 23 & DEG; and 43 & DEG;. The purity of produced hard carbons was approved by EDX to analyze that the purity of hard carbon is greater than 99.9%, making it suitable for industrial use. It was found that the CV curves of the cells created in this work utilizing hard carbon were quite comparable to the CV curves of commercially produced hard carbon cells. According to charge/discharge cycling measurements for constant current at rt, the highest capacity of 210.2 mAh/g using 0.1 A/g is obtained for the material pyrolyzed at 1200 & DEG;C and the capacity fade was found as 0.11. From these promising results, it is thought that the produced hard carbon can be easily used in the production of anode electrodes in commercial Na-ion batteries and technological applications. So it is summarized that P. armeniaca seed shells is one of the main sources for the production of the hard carbon and it can be used as an anode materials in battery cells.Öğe The investigation of structural alteration of raw materials used to attain graphene quantum dots in different prolysis conditions(Elsevier, 2022) Kir, Sifa; Dehri, Ilyas; Onal, Yunus; Esen, Ramazan; Basar, Canan AkmilGraphene quantum dots which is one of the carbon allotrope become widespread an industrial usage due to the unique optical and electrical properties. Graphene Quantum Dots (GQDs) is obtained from the materials such as graphite, glycine, alginate, glucose whose structure contains carbon atoms. In this study, molasses that are used to attain GQDs are carbonized at the temperature of 200, 250, 300, 350 and 400 degrees C for 2 h. The DTA method was used to determine the melting temperature of the molasses. In order to determine the elemental and optical properties of the obtained graphene quantum dots particles, XRD, SEM, Elemental Analysis, Fluorescence Spectrometry techniques and UV-Visible Spectroscopy are used. Mass loss values was also determined and studied its effects were the outcome. The results obtained from these techniques show that the material obtained from the molasses is GQDs.Öğe Laccase production by newly isolated white rot fungus Funalia trogii: Effect of immobilization matrix on laccase production(Elsevier Science Bv, 2013) Birhanli, Emre; Erdogan, Selim; Yesilada, Ozfer; Onal, YunusThe laccase production performance of newly isolated Funalia trogii (F. trogii) immobilized on low-cost activated adsorbents prepared from apricot stone was investigated in inexpensive molasses medium and compared with free pellets. The adsorbents were apricot stone-based activated carbon (AC), Cu-impregnated apricot stone-based activated carbon (Cu-AC) and Fe-impregnated apricot stone-based activated carbon (Fe-AC). Cu-AC and Fe-AC were prepared by chemical activation. The values of BET surface area (S-BET), total pore volume (V-t), micropore surface area (S-mic) and micropore volume (V-mic) which show the pore properties of the activated carbons were 133 m(2) g(-1), 0.105 cm(3) g(-1), 108 m(2) g(-1) and 0.056 cm(3) g(-1) for Cu-AC and 145 m(2) g(-1), 0.112 cm(3) g(-1), 117 m(2) g(-1) and 0.061 cm(3) g(-1) for Fe-AC, respectively. F. trogii attached well on all of these adsorbents. However, the fungus immobilized on Cu-AC produced much higher levels of laccase than the others. The laccase activity obtained in 5 g L-1 molasses media after first cycle and mean laccase activity obtained after three cycles with fungus immobilized on Cu-AC were 29.23 U mL(-1) and 27.04 U mL(-1), respectively. These activities were only 0.25 and 0.39 U mL(-1) with free pellets. The crude laccase from immobilized culture could also decolorize the textile dyes. (c) 2012 Elsevier B.V. All rights reserved.
