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Yayın Adsorption and desorption of major gases on some clays obtained by heating tobacco at certain temperatures(MAS Journal of Applied Sciences, 2022) Yalçınkaya, Zeki; Ceylan, HasanThe tobacco roasting-process was carried out and a study was carried out on the composition of the gases released during this process. It has been determined that the amounts of substances obtained from the studied tobacco are generally less than the amounts of substances obtained in the literature. The volatile gases formed during this roasting were passed over some clay minerals and adsorbed on them. The adsorbed components were desorbed by diethyl ether extraction. Adsorption and desorption analyzes were investigated by GC and TG techniques. The components released during the tobacco-roasting process were first directly obtained and analyzed by gas chromatography. Then, the adsorbing efficiency to clay for each of the components in the vapors from tobacco was calculated by comparing the amount of the component retained in the absence of adsorbent with the amount retained after the component was passed over the adsorbent. The structure of the clay samples used as adsorbent was investigated by chemical analysis and DTA techniques. The adsorption efficiencies are discussed with the physical properties of the clays, the affinities of the volatile components, and their adsorption efficiency. Most of the volatiles adsorbed on the adsorbents were recovered by diethyl ether extraction. Especially benzaldehyde, propionic acid, furfuryl alcohol, 3-methylbutanoic acid and nicotine were recovered with good yield.Yayın Adsorption of aniline, phenol, and chlorophenols on pure and modified bentonite(Springerlink, 2006) Yıldız, Adnan; Gür, Aycan; Ceylan, Hasan; Ceylan, HasanIn the present study, pure bentonite and bentonite modified by HNO 3 , EDTA, and HDTMA are adsorbents. The changes on the surfaces of bentonite samples are studied by IR spectroscopy. The adsorption of aniline, phenol, and phenol derivatives on these adsorbents is examined by means of gas chromatography. As the result of these examinations, it is seen that the adsorption capacities of clay–organic complexes (bentonite– EDTA and bentonite–HDTMA) are higher than those of bentonite-HNO 3 and pure bentonite.Yayın Adsorption of dark compounds with bentonites in apple juice(Elsevier, 2007) Koyuncu, Hülya; Kul, Ali Rıza; Çalımlı, Ayla; Yıldız, Nuray; Ceylan, Hasan; Ceylan, HasanThe adsorption equilibrium of dark-coloured compounds from apple juice has been investigated as a function of several variables including activation conditions of bentonite (heat and acid treatments), clay concentrations (2 10 3–8 10 3 kg clay/dm3 apple juice) and temperature (range of 296–336 K). The adsorption efficiency with acid-activated bentonite was greater than that with heat-activated and native bentonite, depending on surface properties; specific surface areas were 95.31, 71.95 and 71.76m2/g, respectively. Absorbance data at 420nm were fitted reasonably well with the Langmuir and Freundlich isotherms. The parameters K, Q0, Kfr and n were determined for different temperatures. Thermodynamic parameters such as Gibbs free energy (DG), enthalpy (DH) and entropy (DS) change of adsorption were determined as about 3.125, 9.43 and 0.039 kJ mol 1K 1, respectively, for acid-activated bentonite. These parameters were also determined for native and heat-activated bentonites. It was shown that the adsorption process was endothermic, spontaneous and controlled by physical mechanism. The adsorption and desorption rate constants (ka and kd) were obtained separately by applying a geometric approach to the first-order Langmuir model. ka varied from 5.717 10 4 to 20.667 10 3 s 1 and kd from 1.425 10 4 to 7.473 10 3 s 1. The results showed that acid-activated bentonite is more suitable for the adsorption of dark compounds from apple juice.Yayın Application of natural kaolin as support for the immobilization of catalase from bovine liver(Asian Publication Corporation, 2006) Savran, Ali; Alkan, Salih; Demir, Halit; Ceylan, Hasan; Ceylan, HasanCatalase from bovine liver was immobilized on to natural kaolin by physical adsorption method. About 80% of the protein content was immobilized on to support. The activities of immobilized catalase were determined in the reaction mixture containing substrate hydrogen peroxide and free catalase. The effects of reaction temperature, thermostability, stability in organic solvent, leaching and storage studies of immobilized catalase were investigated. Kaolin-immobilized catalase exhibited activities higher by four folds than free catalase after thermal stability test at 70ºC. Immobilized catalase was found to be stable in hexane at room temperature up to 12 d and also showed higher stability than free catalase in the storage study. Leaching studies showed that the immobilized catalase remained fully active even after being washed by 20 mL of solvent. The experimental results showed that physical adsorption is suitable for the attachment of enzyme on to kaolin.Yayın Application of natural kaolin as support for the immobilization of catalase from bovine liver(Asian Publication Corporation, 2006) Savran, Ali; Alkan, Salih; Demir, Halit; Ceylan, Hasan; Ceylan, HasanCatalase from bovine liver was immobilized on to natural kaolin by physical adsorption method. About 80% of the protein content was immobilized on to support. The activities of immobilized catalase were determined in the reaction mixture containing substrate hydrogen peroxide and free catalase. The effects of reaction temperature, thermostability, stability in organic solvent, leaching and storage studies of immobilized catalase were investigated. Kaolin-immobilized catalase exhibited activities higher by four folds than free catalase after thermal stability test at 70ºC. Immobilized catalase was found to be stable in hexane at room temperature up to 12 d and also showed higher stability than free catalase in the storage study. Leaching studies showed that the immobilized catalase remained fully active even after being washed by 20 mL of solvent. The experimental results showed that physical adsorption is suitable for the attachment of enzyme on to kaolin.Yayın An approach for prediction of optimum reaction conditions for laccase-catalyzed bio-transformation of 1-naphthol by response surface methodology (RSM)(Elsevier, 2008) Ceylan, Hasan; Kubilay, Şenol; Aktaş, Nahit; Şahiner, Nurettin; Ceylan, HasanResponse surface methodology (RSM) was successfully applied to enzymatic bio-transformation of 1-naphthol. The experiments were conducted in a closed system containing acetone and sodium acetate buffer, with laccase enzyme. Laccase enzyme used as catalyst was derived from Trametes versicolor (ATCC 200801). The enzymatic bio-transformation rate of 1-naphthol, based on measurements of initial dissolved oxygen (DO) consumption rate in the closed system, was optimized by the application of RSM. The independent variables, which had been found as the most effective variables on the initial DO consumption rate by screening experiments, were determined as medium temperature, pH and acetone content. A quadratic model was developed through RSM in terms of related independent variables to describe the DO consumption rate as the response. Based on contour plots and variance analysis, optimum operational conditions for maximizing initial DO consumption rate, while keeping acetone content at its minimum value, were 301 K of temperature, pH 6 and acetone content of 7% to obtain 9.17 · 10 3 mM DO/min for initial oxidation rate.Yayın Assessment of some trace heavy metals and radioactivity concentration in water of Bendimahi River Basin (Van, Turkey)(Springerlink, 2008) Selçuk Zorer, Özlem; Ceylan, Hasan; Doğru, Mahmut; Ceylan, HasanThe levels of heavy metals were determined in the water of Bendimahi River Basin, statistically analysed and compared to natural gross radioactivity concentration. Fifteen samples of water were collected from Bendimahi River and Van Lake for two seasons in 2005. Water samples were analyzed for eight trace elements and concluded together with gross-alpha and gross-beta radioactivity concentrations. Atomic absorption spectrometry (AAS) was used to determine the concentrations of heavy metals in water samples collected from Bendimahi River basin. Correlation analysis was made for radioactivity and heavy metal concentrations and the Pearson correlation coefficients between gross-alpha and gross-beta radioactivity and heavy metal were determined. The concentrations of all metals were found to be higher than WHO, EC, EPA and TSE-266 guidelines for drinking water, except for Zn and Cu. Generally, the heavy metal concentrations in water samples obtained in May and in August were found to be in sequence of Fe>Zn>Pb>Cr>Cu>Mn> Co>Cd and Fe>Zn>Cu>Pb>Cr>Mn>Co>Cd, respectively. The gross-alpha and gross-beta activity concentration varies between 0.063 and 0.782, 0.021 and 0.816 Bq l?1 in samples collected in May, and 0.009 and 0.037, 0.081 and 3.116 Bq l?1 in samples collected in August.Yayın Bentonite-supported catalase(Serbian Chemical Society, 2005) Alkan, Salih; Ceylan, Hasan; Arslan, Oktay; Ceylan, HasanThe properties of the clay bentonite as a support for enzyme immobilization were studied using the enzyme catalase. Such an immobilization does not result in enzyme inactivation and constitutes a valuable method for immobilizing catalase at high ionic strength. The bentonite-supported catalase was characterized in terms of pH and ionic strength dependencies, thermal and storage stability and kinetic parameters. These studies indicate that bentonite is a valuable support for the simple adsorption of enzymes.Yayın Determination of heavy metals and comparison to gross radioactivity concentration in soil and sediment samples of the Bendimahi River Basin (Van, Turkey)(SpringerLink, 2009) Selçuk Zorer, Özlem; Ceylan, Hasan; Doğru, Mahmut; Ceylan, HasanAn investigation of radioactivity and some heavy metal distribution in soil and sediment of the river basin (Bendimahi River, Van-Turkey) was conducted in two seasons of 2005. The samples of soil and sediment were collected from the basin and investigated for concentrations of some heavy metal and natural radioactivity. Concentrations of Pb, Cr, Mn, Fe, Co, Cu, Zn and Cd have been determined by Atomic Absorption Spectrometry (AAS), gross-alpha and gross-beta activity concentrations have been obtained by using gas-flow proportional counter in nuclear spectroscopic system. Correlation analysis was made for radioactivity and heavy metal concentrations and the Pearson correlation coefficients between gross-alpha and gross-beta radioactivity and heavy metal were determined.Yayın Dissolution kinetics of calcined ulexite in ammonium chloride solutions(Asian Publication Corporation, 2006) Gür, Aycan; Yıldız, Adnan; Ceylan, Hasan; Ceylan, HasanIn this study, the leaching kinetics of calcined ulexite in ammonium chloride solutions were investigated. The effect of calcination temperature, solution concentration, reaction temperature and prehydration were chosen as parameters. It was observed that the rate of dissolution increased with increasing calcination temperature, solution concentration and reaction temperature, while it was not affected by prehydration. Employing graphical and statistical methods, the dissolution rate, based on homogeneous reaction model, can be shown as: (1 - X)-1 - 1 = k(NH4Cl)4/5. The activation energy for the dissolution of the ulexite sample calcined at 160°C was found to be 62.65 kJ mol-1.Yayın Effects of some drugs on enzyme activity of catalase from bovine liver(Asian Publication Corporation, 2006) Alkan, Salih; Savran, Ali; Demir, Halit; Ceylan, Hasan; Ceylan, HasanThe effects of gentamicin sulphate, acetyl salicylic acid, ampicillin sodium, paracetamol, potassium penicillin and augmentin were investigated on the in-vitro enzyme activity of catalase. Catalase (CAT:EC1.11.1.6) was purified from bovine liver by a simple and rapid method. The purification process was done by 2´,5´-ADP sepharose 4B affinity chromatography. Although the purified enzyme showed a tetrameric band on sodium dodecyl sulphate polyacryilamide gel electrophrosis but bovine liver showed a one band. The enzyme activity was measured spectrophotometrically at 240 nm, according to the method of Aebi. From these six drugs, paracetamol, potassium penicillin and augmentin inhibited the activity of the purified enzyme; gentamicin sulphate, acetyl salicylic acid and ampicillin sodium showed little effect on the enzyme activity. The I50 values for these three drugs were as 4.6, 0.35 and 0.49 mM, respectively. The Ki constants were 20, 25 and 25 mM, respectively and they were competitive inhibitors.Yayın Equilibrium and kinetic studies for the sorption of 3-methoxybenzaldehyde on activated kaolinites(Elsevier, 2007) Koyuncu, Hülya; Kul, Ali Rıza; Yıldız, Nuray; Çalımlı, Ayla; Ceylan, Hasan; Ceylan, HasanThe sorption of 3-methoxybenzaldehyde on activated kaolinites has been investigated at different temperatures. Two types of activation tests were performed. The sorption equilibrium was studied by sorption isotherms in the temperature range 303–333K for natural (untreated), thermally and acid activated kaolinites. It was shown that the isotherm shapes were not affected by temperature and activation types of kaolinite. The absorbance data at 312 nm were fitted reasonably well with the Langmuir and Freundlich isotherm models and the model parameters were determined for different temperatures. Thermodynamic quantities such as Gibbs free energy ( G), the enthalpy ( H) and the entropy change of sorption ( S) were determined for natural, thermally and acid activated kaolinites. It was shown that the sorption processes were an endothermic reactions, controlled by physical mechanisms and spontaneously. Adsorption capacity of acid activated kaolinite for 3-methoxybenzaldehyde was higher compared to that of natural and thermally activated kaolinites at various temperatures. The adsorption and desorption rate constants (ka and kd) were obtained separately by applying a geometric approach to the first order Langmuir model. This method provided good conformity between the K from Langmuir parameters and Kgeo (ka/kd) from geometric approach.Yayın Evaluation of the thermodynamic parameters for the adsorption of some hydrocarbons on chemically treated-bentonites by inverse gas chromatography(Springerlink, 2005) Gürkan, Ramazan; Ceylan, Hasan; Şahan, Tekin; Savran, Ali; Kubilay, Şenol; Ceylan, HasanInverse gas chromatography has been used to evaluate the adsorption parameters ( Ha, Hst, Sa and Ga) of some probe molecules, each representing a class of organic (n-hexane, cyclohexane, benzene, n-octane, 1-octene and isooctane) on bentonite and chemically treated-bentonites. The adsorption parameters of the probes on the bentonite samples were determined in infinite dilution region. Adsorption of the organic species was investigated in the temperature range of 200–275?C, using a flame ionization detector, and nitrogen as a carrier gas. The net retention volumes (Vn) of the probes were determined by the help of the retention times (tR) observed on gas chromatograms for each probe. Injection was made at least three times for each probe, obtaining reproducible results of ±0.5%. It was found that benzene exhibits more negative H than for n-hexane and cyclohexane on all of the adsorbents. In addition, it was found that 1-octene exhibits more negative H than for n-octane and isooctane on the chemically treated-bentonites, whereas n-octane exhibits more negative H than for 1-octene and isooctane on the natural bentonite. Also, interactions of benzene with the natural- and chemically treated-bentonites were found to be stronger than those of n-hexane and cyclohexane with the same carbon number. Again, interactions of the 1-octene with the chemically treated-bentonites were found to be stronger those of n-octane and isooctane with the same carbon number. On the contrary, interactions of n-octane with the untreated-bentonite were found to be stronger than those of 1-octene and isooctane.Yayın Gross alpha and beta radioactivity concentration in water, soil and sediment of the Bendimahi River and Van Lake (Turkey)(Springerlink, 2009) Selçuk Zorer, Özlem; Ceylan, Hasan; Doğru, Mahmut; Ceylan, HasanThe concentrations of the natural radioactivity in water, soil and sediment samples collected from Bendimahi River which originates near the Tendürek Mountain (Van, Turkey), its tributaries and Van Lake (Turkey) were measured. The gross-alpha and gross-beta radioactivity concentrations were investigated in May and August in 2005. Determination of the gross-alpha and gross-beta radioactivity of river water, soil and sediment samples was obtained by using gas-flow proportional counter, PIC-MPC 9604-?/? counter. In water samples, the obtained results show that in May; gross-alpha and gross-beta activity concentrations varied between 0.063–0.782 and 0.021–0.816 Bq l?1 and in August the values were 0.009–0.037 and 0.081–3.116 Bq l?1, respectively. The gross-alpha and gross-beta activity concentrations in soil samples ranged from 0.800 to 4.277 Bq g?1 and 0.951 to 11.773 Bq g?1 in May and 0.686 to 4.713 Bq g?1 and 0.073 to 9.524 Bq g?1 in August, respectively. Concentrations ranging from 0.782 to 4.596 Bq g?1 and from 0.482 to 10.372 Bq g?1 in May and from 0.580 to 5.824 Bq g?1 and from 0.303 to 9.702 Bq g?1 in August for gross-alpha and gross-beta radioactivity were observed in sediments, respectively.Yayın Influence of acid activation on the adsorptive properties of Keskin clay(Ankara Üniversitesi, 1981) Ceylan, Hasan; Sarıkaya, Yüksel; Ceylan, HasanKeskin/Ankara bölgesinden alınan kil, sülfürik asit ile farklı oranlarda karıştırılarak "kuru yöntem" ile aktiflenmiştir. Aktivasyondan sonra vakumda ve 160 derecede 2 saat süre ile ısıtılan ürünlerin azot gazı adsorpsiyonu ile yüzey alanları tayin edilmiştir. Yüzey alanının %30 asit oranına dek arttığı, sonra da küçük değerle hızla düştüğü gözlenmiştir. Asit oranı %30 iken yapılan aktivasyonda 262 m2/g değerindeki en büyük yüzey alanı bulunmuştur.Yayın The investigation of the adsorption of propylamine, dipropylamine and threepropylamine on sepiolite specimens by infrared spectroscopy(Ankara Üniversitesi, 1999) Ceylan, Hasan; Selçuk, A.; Sarıkaya, Yüksel; Alemdaroğlu, Tülay; Ceylan, HasanPropylamine, dipropylamine and triplopylamine were adsorbed on sepiolite specimens under reflux, at their normal boiling points. The infrared spectra of the original and the amine adsorbed specimens were recorded before and after heat treatments between 50-400 degree. The examination of the spectra revealed that the adsorption of amines took place by the replacement of the zeolitic water in the pores of the sepiolite by the amines.Yayın Optimization of biosorption of Zn(II) ions from aqueous solutions with low-cost biomass Trametes versicolor and the evaluation of kinetic and thermodynamic parameters(DESALINATION PUBL, 2016) Sahan, Tekin; Ceylan, Hasan; Aktas, Nahit; Ceylan, HasanThe optimum biosorption conditions for removing Zn(II) ions from aqueous solutions by naturally powdered Trametes versicolor were successfully evaluated through a multi-step response surface methodology. The conducted experiments were based on a central composite design. The most influential factors on the biosorption process were initial pH (5-6.7), temperature (18-30 degrees C), and initial Zn(II) concentration (30-70mg L-1). Based on the statistical analysis, the optimum conditions for Zn(II) biosorption were found to be 5.74, 24.57 degrees C, and 60.95mg L-1 for initial pH, temperature and Zn(II) concentration, respectively. Under these optimum conditions, the maximum amount of biosorbed Zn(II) ions was 43.87mg Zn(II) per g dry cells. The proposed quadratic model fits very well to the experimental data. Furthermore, a Dubinin-Radushkevich isotherm model described the biosorption of Zn(II) ions on the biosorbent better than the common isotherm models, while kinetic studies showed that Zn(II) biosorption matched pseudo-second-order kinetics. Moreover, thermodynamic parameters, such as the changes in free energy, enthalpy, and entropy, were also calculated for the biosorption of Zn(II) ions onto T. versicolor. It was concluded that naturally powdered T. versicolor is a suitable biosorbent for the removal of Zn(II) ions from aqueous solutions.Yayın Optimization of removal conditions of copper ions from aqueous solutions by Trametes versicolor(Elsevier, 2010) Şahan, Tekin; Ceylan, Hasan; Şahiner, Nurettin; Aktaş, Nahit; Ceylan, HasanA multi-step response surface methodology was successfully applied to optimize the biosorption conditions for the maximum removal of Cu(II) ions from aqueous solutions using Trametes versicolor fungi as a biosorbent. In the first step, the most effective medium factors, which are pH, temperature and initial Cu(II) concentration, on biosorption of Cu(II), were determined through Plackett–Burman Design. Then steepest accent followed by central composite design steps were utilized to evaluate the optimum biosorption conditions for the maximum Cu(II) ions removal. Based on the statistic analysis; the optimum conditions were obtained 5.51, 20.13 C and 60.98 mg/L as medium pH, medium temperature and initial Cu(II) concentration, respectively. Finally the analysis of variance (ANOVA) of central composite design showed the proposed quadratic model fitted experimental data very well.Yayın Relationship between ethylene adsorption isotherms and GC retention on carbowax-coated porous graphite(SpringerLink, 1992) Knox, John Henderson; Ceylan, Hasan; Ceylan, HasanThe objective of this work was to correlate adsorption isotherms of ethylene at ?78°C on porous graphitic carbon (PGC) with gas chromatographic performance, the intention being that such isotherms could be used as a quality control test for PGC's in general, whether used for GC, HPLC or other adsorptive purposes. GC of test solutes shows that severe peak tailing on bare PGC is removed almost totally by a coating PGC with as little as 0.05% by weight of Carbowax 1500. Surprisingly there is little corresponding change in the ethylene adsorption isotherms, although it is possible to distinguish small differences at surface coverages below 5% of a monolayer of ethylene. Further work is required to establish a useful QC test.Yayın Removal of some heavy metal cations from aqueous solution by adsorption onto natural kaolin(SageJournals, 2005) Ceylan, Hasan; Şahan, Tekin; Gürkan, Ramazan; Kubilay, Şenol; Ceylan, HasanThe adsorption removal of some heavy metal cations such as Cu(II), Zn(II) and Co(II) from aqueous solution onto kaolin has been studied using the batch method with initial metal ion concentrations within the range 15–70 mg/l. The percentage adsorption and equilibrium concentrations were determined by means of atomic absorption flame photometry as a function of adsorbate concentration, pH and temperature. Ion-exchange studies showed that over the complete concentration range studied the adsorption ratios for metal cations adsorbed onto kaolin correlated with the linear forms of the Langmuir, Freundlich and Dubinin–Kaganer–Radushkevich (DKR) adsorption isotherms. The cationexchange capacity of kaolin towards each metal ion studied was evaluated. It was found that the adsorption phenomena depended on the charge density and diameter of the hydrated ion. The equilibrium studies demonstrated that the selectivity of the ions followed the sequence Zn(II) > Cu(II) > Co(II) at pH 7.0. Calculation of thermodynamic parameters such as the standard enthalpy (?H0), Gibbs free energy (?G0) and entropy (?S0) showed that the adsorption of the heavy metal ions studied onto kaolin was an endothermic process which was favoured at higher temperatures. These results show that natural kaolin has a considerable potential for the removal of heavy metal cationic species from aqueous solution and wastewater.
