Browsing by Author "Abali, Y"
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Item Cr(VI) adsorption by waste acorn of Quercus ithaburensis in fixed bedsMalkoc, E; Nuhoglu, Y; Abali, YThe adsorption of Cr(VI) onto waste acorn of Quercus ithaburensis was studied using fixed-bed adsorption. The experiments were conducted to study the effect of important design parameters such as flow rate, solution pH and particle size of adsorbent. Decrease in adsorbent particle size and flow rate produced a better bed capacity. Also an increase in flow rate and particle size resulted in a decrease in the bed volumes at the breakthrough. The highest bed capacities of fixed-bed column were obtained at pH 2.0. In the beginning of all the pH experiments, the effluent pH increased dramatically and then dropped and approached lower values. The breakthrough data obtained for Cr(VI) was adequately described by the Thomas and Yoon-Nelson adsorption models. Good agreement between the predicted theoretical breakthrough curves and the experimental results were observed. This study indicated that the waste acorn of Quercus ithaburensis can be used as an effective and environmentally friendly adsorbent for the treatment of Cr(VI) containing wastewaters. (c) 2006 Elsevier B.V. All rights reserved.Item Analyses of boronic ores and sludges and solubilities of boron minerals in CO2-saturated waterErdogan, Y; Aksu, M; Demirbas, A; Abali, YIn this study, the potential of boron in Turkey, commercial most-used compounds of boron and their production trends according to years and analyses of boronic samples obtained different sources were investigated. Besides classic analysis technics, X-ray fluorescence spectrometric (XRF) and flame photometric methods were carried out for boronic samples. Chemical compositions of original and concentrated samples were studied with respect to the contents of B, Li, Ca, Al, Fe, Mg, S, As, Si, Sr and Na. The leaching of boric acid with CO2-saturated water from boron minerals was also investigated. (C) 1998 Elsevier Science B.V. All rights reserved.Item Chemically modified starch with silicon quantum dots: Structures and propertiesSaman, F; Al, E; Boylu, B; Arslan, O; Abali, YAttachment of Silicon quantum dots (Si QDs) onto starch via sol-gel controlled covalent bonding to form hybrid starch particles was developed to modulate the optical, physical, and mechanical features of starch. Fabricated Si QDs chemically interacted with -OH side groups due to the sol-gel reactions on the starch molecules providing a detectable new molecular bonding to result in fluorescent emission. The produced structures formed nonlinear morphological orientations that provide a nanocomposite material platform for a facile molecular marking in daily applications. Fluorescent tag attachment onto the starch structures by Si quantum dots via covalent bonding was developed for the varying implications including fluorescent materials, sensors, surface coating purposes. A well designed quantum dot synthesis and starch treatment was applied to vary the optical, physical, and mechanical features of the starch particles on molecular level resulting a promising new material for visible light fluorescent material applications.Item Metal borate nanostructures for industrial antibacterial ceramic fabricationAgus, O; Arslan, O; Abali, YSilver and copper borate nanostructures were mechanistically synthesized for novel boron-containing antibacterial applications. Different concentration, temperature, time parameters were varied for obtaining hierarchical formulations. Metal borate nanostructures showed interesting crystalline and optical properties since temperature and concentration adjustments provided correlated shape and surface properties with around 300 nm size. Chemical analysis and crystallinity of both copper and silver formulations were conducted with X-ray diffraction and unveiled that especially temperatures ranging from 40 to 90 degrees C has a huge impact on the formation of nanostructures. X-ray photoelectron spectroscopy analysis comprehensively provided all atomic compositions especially about boron atom at 191-192 eV range. Additionally, energy-dispersive X-ray analysis with scanning electron microscope measurements revealed the morphological properties of the nanostructures and showed the purity of the obtained materials. Finally, metal borate-containing glazes were obtained on 1 x 1 cm samples for antibacterial tests against Gram-positive and Gram-negative microorganisms.Item Dissolution kinetics of phosphate rock with Cl-2 gas in waterAbali, Y; Colak, S; Yartasi, AIn this study the dissolution kinetics of phosphate rock with Cl-2 gas in aqueous media were investigated. The effect of particle size, solid-to-liquid ratio, gas flow rate, reaction temperature and stirring speed on the dissolution process were determined. It was observed that the dissolution of the phosphate rock increased with increasing gas flow rate and stirring speed and with decreasing particle size and solid-to-liquid ratio. Increasing reaction temperature increased the dissolution slightly between 12 degrees C and 30 degrees C and decreased it between 40 degrees C and 80 degrees C. By analysis of the experimental data using heterogeneous kinetic models it was determined that the dissolution process is controlled by diffusion through the fluid layer.Item Determination of the optimum conditions for dissolution of magnesite with H2SO4 solutionsAbali, Y; Çopur, M; Yavuz, MBasic data on leaching of magnesite (M-CO3) with sulphuric acid are of interest from the point of view of the industrial process for obtaining pure MgSO4. The Taguchi method was used to determine the optimum conditions for the dissolution of magnesite in H2SO4 solutions. The experiments were performed within the ranges mentioned herein i.e. 20-65 degrees C for reaction temperature, 0.5/100-10/100 g/mL for solid-to-liquid ratio, 0.2-5 M for acid concentration, 5-60 min for reaction time and 150-750 rpm for stirring speed. The optimum conditions for these factors were found to be 65 degrees C, 5/100 g/mL, 2 M, 60 min and 300 rpm, respectively. Under these conditions, the dissolution mass fraction Of MgCO3 in H2SO4 solutions were w = 96.32%.Item OPTIMIZATION OF DOLOMITE ORE LEACHING IN HYDROCHLORIC ACID SOLUTIONSAbali, Y; Bayca, SU; Arisoy, K; Vaizogullar, AIIn this study, the Taguchi method was used to determine the optimum conditions for leaching of dolomite ore in hydrochloric acid solutions. The experimental parameters were leaching temperature, solid-to-liquid ratio, acid initial concentration, leaching time and stirring speed. The following optimum leaching parameter levels were found: temperature 50 degrees C, solid-to-liquid ratio 2%, acid concentration 20 g/cm(3) (2 mol/dm(3)), stirring speed 450 rpm, leaching time 5 min. Under the optimum process conditions, the dolomite ore leaching efficiency was about 83%.Item The optimisation of the dissolution of phosphate rock with Cl-2-SO2 gas mixtures in aqueous mediumAbali, Y; Colak, S; Yapici, SIn the present study, aimed at the production of phosphate compounds, the optimum process conditions were sought for the dissolution of phosphate rock from the Mardin-Mazidagi concentrate, The dissolution of this phosphate rock in aqueous solution saturated with a mixture of Cl-2-SO2 gases was optimized by passing Cl-2 gas through the final solution. Reaction temperature, solid-liquid ratio, Cl-2 gas flow rate, reaction period and stirring speed were employed as parameters. Using the Taguchi Fractional Design Method, it was found that the optimum process conditions, at which 93.35% P2O5 conversion was reached, were as follows: Reaction temperature: 20 degrees C Solid-liquid ratio: 1/7 (w/v) Cl-2 gas flow rate: 120 cm(3) min(-1) Reaction period: 20 Stirring speed: 600 min(-1).Item Extending experimental data to investigate phosphogypsume use in light brick by Artificial Neural NetworksYurdusev, MA; Kumanlioglu, AA; Abali, Y; Zeybek, MS; Canpolat, FIn this study, usability of wastes produced in phosphoric acid plants in structural brick manufacture has been investigated. A series of experiments for three different material combinations namely original waste plus normal brick clay, washed waste plus normal brick clay and normal brick clay with no additive were carried out to achieve this end. The results have shown that the industrial wastes considered improve the performance of the bricks. However, the results have also shown that further investigations are needed to explore the effects of interim or outer values on the performance of the bricks. To active that end, a neural experimental study is adopted. The outcome of these artificial tests have provided the appropriate values for the waste addition rate, firing speed and firing temperature.Item Facile and controlled production of silver borate nanoparticlesAgus, O; Abali, Y; Arslan, O; San Keskin, NONanosized silver (Ag) borate particles were synthesized under facile and controlled conditions for the antibacterial ceramic applications. Obtained powder materials were characterized comprehensively for the detection of crystallinity, particle size, morphology and surface characteristics. Since obtained borate particles must be optimized by comparing their size, shape and composition, a statistical method (Taguchi Method) was used. Taguchi method allowed the control and deep insight on the variables namely temperature, reaction time, mol ratio and stirring speed. Since obtained nanoparticles can be easily modified and dispersed in ceramic matrixes, formation parameters for the best antibacterial glaze composition were defined. Structural analysis and crystallinity investigation with x-ray diffraction showed that temperature has a huge impact on the formation of nanoparticles as diffraction patterns revealed. Scanning Electron Microscopy unveiled that morphology of the nanoparticles are relatively spherical and EDX revealed that there is no other impurities. Synthesized nanoparticles were utilized for the 1 x 1 cm ceramic samples for antibacterial applications. Results showed that gram positive and gram negative bacterias are deactivated as tests revealed and reported.Item Neural extension of experimental data to investigate using phosphogypsume in light brick productionYurdusev, MA; Kumanhoglu, AA; Abali, Y; Zeybek, MSIn this study, usability of wastes produced in phosphoric acid plants in structural brick manufacture has been investigated. There are several parameters involved in using these wastes in brick production namely the rate of added waste, firing speed and firing temperature. The performance of these parameters can be measured by several criteria such as natural drying shortening, water absorption and weight loss. Therefore, so many experiments are needed to investigate the effects of these parameters on the bricks produced with these wastes. The result of a series of experiments were utilized to achieve this end. The results have shown that the industrial wastes considered improve the performance of the bricks in terms of the criteria mentioned above. However, the results have also shown that further investigations are needed to explore the effects of interim values on the performance of the bricks. To achieve that end, a neural experimental study is adopted. For this purpose, the results of the experiments conducted were used to construct an artificial neural network. The trained and tested network was then used to check the effects of 280 different combinations for each type of material mixtures mentioned. The outcome of these artificial tests have provided the optimal values for the waste addition rate, firing speed and firing temperature based on the four criteria mentioned previously. (c) 2008 Elsevier Ltd. All rights reserved.Item Investigation of Leaching Kinetics of Ulexite Waste in Oxalic Acid SolutionsBayca, SU; Kocan, F; Abali, YThe dissolution of ulexite waste in oxalic acid solutions was studied in a batch reactor after characterization of the waste by X-ray diffiaction (XRD) analysis and X-ray fluorescence (XRF) analysis. The dissolution parameters in this study were acid concentration, stirring rate, and reaction temperature. The experimental data were examined using homogeneous and heterogeneous kinetic models, and the dissolution kinetics of the waste was determined to be a first-order reaction control model. The activation energy of ulexite waste in oxalic acid solution was also calculated. It was observed that the dissolution rate increased with increasing reaction temperature, stirring rate and acid concentration. The kinetic model of the dissolution process was determined to be a first-order reaction control model. The activation energy was found to be 41.09 kJ mol(-1).Item The sorption behavior of a nickel-insolubilized humic acid system in a column arrangementGezici, O; Kara, H; Ersöz, M; Abali, YThe sorption characteristics of insolttbilized humic acid (IHA) were investigated for Ni (II) in a column arrangement. The sodium form of the IHA (INaA) was used as a solid phase. Column operations were performed with five steps and all of them were monitored continuously by a flowthrough cell-adapted UV-Vis spectrophotometer. Thus, all solid-phase extraction (SPE) steps were visualized by breakthrough curves and analyses progress were evaluated. However, all calculations and evaluations were focused on the atomic absorption spectrophotometric (AAS) analyses of the solutions collected during the stripping steps. There was a high correlation (r(2), 0.972) between peak area and AAS data of stripping steps. The effect of concentration and pH of the loading solution onto sorption of Ni (II) by INaA was investigated. Sorption characteristics were evaluated by using Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) adsorption isotherms, as well as by Scatchard plot analysis. Multilayer sorption was found to be agreeable for Ni (II). From the D-R isotherm the mean free energy of sorption (E) was calculated (6.65 kJ mol(-1)) and attributed to the multilayer sorption. Finally, the sorption characteristic of the INaA-Ni (II) system was compared with that of the INaA-Cu (II) system, and possible separation of two ions in a binary mixture system is discussed. (c) 2005 Elsevier Inc. All rights reserved.Item Controlled modulation of 1D ZnO nano/micro structures: Evaluation of the various effects on the photocatalytic activityArslan, O; Abali, YEffects of the concentration, temperature and precursor type on the fabrication of the elongated ZnO nano/ micro structures were comprehensively investigated. Analytical investigations such as SEM and statistical analysis of the elongated ZnOnano/micro structures provided wide information about the growth behavior and final geometries. Different temperatures for the 1 D ZnO formation clearly revealed that hexagonally grown ZnO nanorods were obtained. Especially low crystal diffraction characteristics at low temperature (55 degrees C) implied that ZnO nano/micro rod formation requires some minimum conditions for the formation of an efficient photocatalyst. All XRD investigations together with SEM and TEM supported the ligand ordered elongation conducted by diverse beginning concentrations. Since temperature found as a highly dominant actor for morphology and surface sequence as manifested in crystallinity, morphology and photocatalytic results, we have systematically summarized the growth conditions of the ZnO nano/micro rods from same precursor.Item REMOVAL OF METHYLENE BLUE BY NATURAL AND Ca AND K-EXCHANGED ZEOLITE TREATED WITH HYDROGEN PEROXIDECanli, M; Abali, Y; Bayca, SUA comparison was made of influence of physically adsorbed methylene blue (MB) dye on the physicochemical properties of Manisa-Akdere zeolite (natural zeolite) and zeolite modified with K and Ca (all samples treated with hydrogen peroxide before modification) using batch adsorption technique. After elementary characterization of this adsorbent, the effects were investigated of initial MB concentration, pH, contact time, stirring rate, adsorbent dosage and temperature on the selectivity and sensitivity of the removal process. A larger adsorption of the dye was observed for modified zeolite (42.7 mg/g) than for natural zeolite (28.6 mg/g) per gram of an adsorbent after all zeolite samples treated with hydrogen peroxide. Zeolite treated with H2O2 showed higher adsorption capacity than untreated zeolite samples. The Langmuir model (R-2 values between 0.959 and 0.996) fitted the experimental data better than the Freundlich model (R-2 values between 0.804 and 0.988). The adsorption process was found to be slightly influenced by adsorbent dosage, contact time and temperature. Optimum pH for adsorption of MB was found to be at 7. Adsorption equilibrium attained within 30 minutes. The sorption of MB increased slightly with rising temperature. In addition, adsorption values rose with modification Ca-Exchanged (after H2O2 treatment) > K-Exchanged (after H2O2 treatment) > Zeolite treated with H2O2 > Ca-Exchanged >K-Exchanged >Natural Zeolite.Item DISSOLUTION KINETICS OF SMITHSONITE IN BORIC ACID SOLUTIONSAbali, Y; Bayca, SU; Gumus, RThe dissolution of smithsonite in boric acid solutions was investigated. The influence of the reaction temperature, acid concentration, solid-to-liquid ratio, particle size and stirring speed on the zinc extraction were determined in the experiments. The results show that the dissolution rate increases with increasing acid concentration and reaction temperature, and with decreasing particle size and solid-to-liquid ratio. The dissolution results were analyzed by reaction control models. The activation energy of smithsonite in boric acid solution was also calculated.Item Leaching kinetics of ulexite in oxalic acidAbali, Y; Bayca, SU; Mistincik, ELeaching of ulexite in oxalic acid, which is an organic acid, was studied. The parameters were solid-to-liquid ratio, acid concentration, stirring speed and temperature. The experimental data were applied to the homogeneous and heterogeneous kinetic models to determine the best one. The results showed that the leaching rate increases with increasing reaction temperature, stirring speed, acid concentration, but decreases with solid-to-liquid ratio and particle size. The leaching kinetics of ulexite was determined as the product layer model. The activation energy of the process was calculated.Item Kinetics of oxalic acid leaching of tincalAbali, Y; Bayca, SU; Mistincik, EThe leaching kinetics of tincal in oxalic acid solutions was investigated in this study. The effects of parameters reaction temperature, acid concentration, solid to liquid ratio, particle size and stirring speed on tincal leaching were determined in the experiments. It is observed that the leaching rate increases with increasing reaction temperature, stirring speed and decreasing solid to liquid ratio and particle size. The experimental data tested the reaction control models and the best model for the leaching rates of tincal was the product layer model. The activation energy of the process was calculated as 35.14 kJ mol(-1). (c) 2006 Elsevier B.V. All rights reserved.Item Some Heavy Metal Determination by ICP-OES in Human Scalp Hair (In Three Different Regions of Manisa)Çelik, A; Abali, Y; Edgünlü, G; Uzunoglu, S; Tirtom, VNThe aim of this study was to determine the levels of As, Cd, Mn, Cr, Fe, Pb, Hg, Zn and Se in hair samples collected from the nape of the neck of voluntary people living or working in the industrial region, city center and countryside of Manisa province. The concentrations of As, Cd, Mn, Cr, Fe, Pb, Se, Zn were determined by ICP-OES. The measured values of trace elements in human hair samples were compatible to the reference values given in the literature. The measured values of As, Hg, Cr, Cd, Se and Pb were found below the detection limit of the method. Zn, Mn and Fe were statistically analysed and evaluated. When the Fe and Mn values of the hair samples collected from the industrial region were compared with the data from both the city center and countryside (ANOVA), the differences were meaningful and significant, but the differences for Zn between the industrial region, city center and countryside were found to be insignificant.Item Effect of gamma irradiation on the thermal and mechanical behaviour of polypropylene and polyethylene blendsSirin, M; Zeybek, MS; Sirin, K; Abali, YThis study investigates the effect of radiation over polypropylene and polyethylene blends samples with different weight ratios. 10, 30, 50, 70, and 100 kGy doses of radiation were applied from the 60Co source on the polymer blends obtained by mixing polypropylene (PP) and polyethylene (LDPE) samples with different molecular weights in different ratios by weight. Melting flow rates (MFI), hardness, tensile strength at yield, tensile strength at break, elongation at break, differential scanning calorimetry (DSC), and thermogravimetric analysis (TG) of the samples were examined. When melting flow index of the samples was examined, it was determined that there was a significant increase in the speed of melting flow in connection with increasing radiation doses. When the mechanical analyses of the samples were examined, there was a significant decrease in tensile strength at yield, tensile strength at break, and elongation at break values. Particularly, as the samples with 100 kGy dose had deformation, there was no reading for these values. When DSC analysis of the samples was examined, depending on the increasing radiation dose, there was a decrease in melting temperature Tm, crystallization temperature Tc, melting enthalpy Delta Hf, crystallization enthalpy Delta Hc and the rate of crystallization Xc values. It was observed that there was a mass loss against heat in TG analysis of samples.