Browsing by Author "Kul, Ali Riza"

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Adsorption Equilibrium and Thermodynamics of Diatomite (caldiran/Van) Onsome Textile Dyes
(Chem Soc Pakistan, 2018) Alkan, Salih; Caliskan, Meliha; Irende, Ilhan; Kul, Ali Riza
Together with increasing world population, developing technology and rapid industrialization process bring about environmental pollution. Nowadays, cleaning environment from industrial wastes and pollutants is of utmost importance. Some organic materials, produced by the majority of textile waste, cause environmental pollution. Many dyestuffs, which are hazardous for environment, can be released to environment by industrial organizations without having any precaution. Textile dyestuffs, being above certain concentrations, can cause poisoning of aquatic organisms. Dyestuffs can be classified as following: Anionic: Direct, acid and reactive dyes Cationic: Basic dyes Nonionic: Disperse dyes It can be said that most problematic group of dyes used in the textile industry is the group of reactive dyes. Analyzing performed studies shows that these views are supported. Today, adsorption techniques are gaining ground due to efficiency in removal of too stable pollutants. Adsorption is, economically, a reasonable method and we can say that it provides formation of high quality products. With the development of industry search for materials, to be used as adsorbent for removal of factory wastes and water-soluable dyestuffs from water, accelerates. In our study, from natural adsorbents diatomite(Calthran/VAN) is used as an adsorbent material. The removal of natural red and basic blue from aqueous solution using diatomite, was investigated with respect to the adsorbent dose (0,02 g), initial concentration (20-140 mg/L), temperature (between 25 and 45 degrees C), on batch adsorption were studied as a function of contact time. The lineer Langmuir, Freundlich and Temkin adsorption equations were applied to describe the equilibrium isotherms. In addition, the pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model. Thermodynamic parameters such as the enthalpy (Delta,H degrees), Gibbs free energy (Delta G degrees) and entropy (Delta S degrees) shoved spontaneous and endothermic in nature of adsorption for both of adsorbents.
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. Funda
Activated 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.
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, Yunus
The 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.
Adsorption of Dark Compounds With Bentonites in Apple Juice
(Elsevier Science Bv, 2007) Koyuncu, Hulya; Kul, Ali Riza; Calimli, Ayla; Yildiz, Nuray; Ceylan, Hasan
The 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 x 10(-3)-8 x 10(-3) kg clay/dm(3) 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 71.76 m(2)/g, respectively. Absorbance data at 420 nm were fitted reasonably well with the Langmuir and Freundlich isotherms. The parameters K, Q(0), K-fr and n were determined for different temperatures. Thermodynamic parameters such as Gibbs free energy (Delta G), enthalpy (Delta H) and entropy (Delta S) change of adsorption were determined as about -3.125, 9.43 and 0.039 kJ mol(-1) K-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 (k(a), and k(d)) were obtained separately by applying a geometric approach to the first-order Langmuir model. k(a) varied from 5.717 x 10(-4) to 20.667 x 10(-3) s(-1) and k(d) from 1.425 x 10(-4) to 7.473 x 10(-3) s(-1). The results showed that acid-activated bentonite is more suitable for the adsorption of dark compounds from apple juice. (c) 2006 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.
Adsorption of Malachite Green Dye Using Pinus Sylvestris: Isotherm, Kinetics and Thermodynamics Studies
(Parlar Scientific Publications (p S P), 2019) Kul, Ali Riza; Aldemir, Adnan; Elik, Hasan
In this study Pinus sylvestris shavings powder (PiSP) was utilized as an adsorbent for the removal of Malachite Green (MG) which is one of the common basic dyes, from aqueous solution. The adsorption experiments were carried out in a batch system and effects of initial dye concentration, interaction time and temperature were investigated. Langmuir, Freundlich and Temkin adsorption isotherms have been used to model equilibrium data. Freundlich isotherm model becomes more convenient option compared with Langmuir and Temkin models. Freundlich model coefficients are raise as the temperature rises, showing that the adsorption process becomes favorable higher temperature. Kinetic parameters were determined by pseudo first order (PFO), pseudo second order (PSO) and intraparticle diffusion (IPD) models. Results indicated that experimental and calculated qe values close to each other explained that this process fits PSO kinetic model with higher R-2 values than other two models. Kinetic constants become closer to both temperatures and initial concentrations and qe values are increases with increasing concentration of MG. Initial dye concentration elevates from 10 to 60 mg/L, dye adsorption capacity onto PiSP from 3.28 to 22.88 mg/g, 3.58 to 24.06 mg/g and 3.88 to 25.78 mg/g for 298, 308 and 318K, respectively. Thermodynamic parameters for instance free energy (Delta G), enthalpy (Delta H) and entropy (Delta S) of this separation process are determined from -2757,7 J/mol, 6550,68 J/mol and 12,73 kJ/cool, respectively. The negative values of Delta G degrees showed that this separation process was endothermic and natural. The research results demonstrate that PiSP may be an alternative material than costly adsorbents for dye removal.
Adsorption of Pb(Ii) Ions From Aqueous Solution by Native and Activated Bentonite: Kinetic, Equilibrium and Thermodynamic Study
(Elsevier, 2010) Kul, Ali Riza; Koyuncu, Huelya
In this study, the adsorption kinetics, equilibrium and thermodynamics of Pb(II) ions on native (NB) and acid activated (AAB) bentonites were examined. The specific surface areas, pore size and pore-size distributions of the samples were fully characterized. The adsorption efficiency of Pb(II) onto the NB and AAB was increased with increasing temperature. The kinetics of adsorption of Pb(II) ions was discussed using three kinetic models, the pseudo-first-order, the pseudo-second-order and the intra-particle diffusion model. The experimental data fitted very well the pseudo-second-order kinetic model. The initial sorption rate and the activation energy were also calculated. The activation energy of the sorption was calculated as 16.51 and 13.66 kJ mol(-1) for NB and AAB, respectively. Experimental results were also analysed by the Langmuir, Freundlich and Dubinin-Redushkevich (D-R) isotherm equations at different temperatures. R-L separation factor for Langmuir and the n value for Freundlich isotherm show that Pb(II) ions are favorably adsorbed by NB and AAB. Thermodynamic quantities such as Gibbs free energy (Delta G), the enthalpy (Delta H) and the entropy change of sorption (Delta S) were determined as about -5.06, 10.29 and 0.017 kJ mol(-1) K-1, respectively for AAB. It was shown that the sorption processes were an endothermic reactions, controlled by physical mechanisms and spontaneously. (c) 2010 Elsevier B.V. All rights reserved.
Adsorption of Zinc(Ii) on Diatomite and Manganese-Oxide Diatomite: a Kinetic and Equilibrium Study
(Elsevier, 2011) Caliskan, Necla; Kul, Ali Riza; Alkan, Salih; Sogut, Eda Gokirmak; Alacabey, Ihsan
The removal of Zn(II) ions from aqueous solution was studied using natural and MnO2 modified diatomite samples at different temperatures. The linear Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption equations were applied to describe the equilibrium isotherms. From the D-R model, the mean adsorption energy was calculated as >8 kJ mol(-1), indicating that the adsorption of Zn(II) onto diatomite and Mn-diatomite was physically carried out. In addition, the pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model. Thermodynamic parameters such as the enthalpy (Delta H-0), Gibbs' free energy (Delta G(0)) and entropy (Delta S-0) were calculated for natural and MnO2 modified diatomite. These values showed that the adsorption of Zn(II) ions onto diatomite samples was controlled by a physical mechanism and occurred spontaneously. (C) 2011 Elsevier B.V. All rights reserved.
Application of Machine Learning Methods To Removal Percentage Prediction for Malachite Green Adsorption on Kaolinite
(desalination Publ, 2022) Canayaz, Murat; Aldemir, Adnan; Kul, Ali Riza
In this study, the removal percentage was estimated using machine learning methods, such as artificial neural network, radial basis function neural network, support vector regressor, and random forest regressors, for data obtained during Malachite green adsorption on kaolinite as an adsorbent in an aqueous solution. Important process parameters, including initial dye concentration, sonication time and temperature, were investigated. Statistical evaluation metrics such as R2, mean squared error, and root mean square error were used to evaluate the performance of the models. Among these models, the artificial neural network was more successful compared to other models with 0.98 R2 values for three temperatures. Radial basis function neural network and random forest regressors were observed to achieve successful results. In this study, the results obtained from the machine learning methods are given comparatively. The initial dye concentrations increased from 10 to 60 mg L-1, the removal percentage of Malachite green on kaolinite increased from 68.71% to 79.61% for 298 K, 72.26% to 82.58% for 308 K and 78.75% to 85.91% for 318 K, respectively. Isotherm, kinetic and thermodynamic calculations for Malachite green removal by kaolinite were completed. The equilibrium of Malachite green adsorption onto kaolinite was best described by the Langmuir isotherm and the kinetics of the process followed the pseudo-second-order model, which had the highest correlation values. Thermodynamic analysis of experimental data suggests that the adsorption process is spontaneous and endothermic in nature.
Biosorption Study for Removal of Methylene Blue Dye From Aqueous Solution Using a Novel Activated Carbon Obtained From Nonliving Lichen (Pseudevernia Furfuracea (L.) Zopf.)
(Elsevier, 2020) Koyuncu, Hulya; Kul, Ali Riza
To the best of our knowledge, there is no study on the utilization of lichens in the production of activated carbon while lichens are natural, renewable and cheap sources. In this study, a novel activated carbon (ACLPF) from non-living lichen Pseudevernia furfuracea (L.) Zopf. (LPF) was produced, and physicochemical and morphological characterization of the ACLPF were examined with the help of Brauner-Emmett-Teller surface area (BET), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) techniques. The obtained ACLPF had a high surface area (851.24 m(2)g(-1)) and a large pore volume (0.225 cm(3)g(-1)) with micropore size distribution (1.06 nm). To investigate the usability of the ACLPF in wastewater treatment, batch mode biosorption experiments were carried out, and the effect of various parameters on methylene blue (MB) dye removal from aqueous solution were studied. The experimental data were fitted with 4 different kinetic models (pseudo first-order (PFO), pseudo second-order (PSO), Elovich model (EM) and intra-particle diffusion (IDM)) and 3 different isotherm models (Langmuir, Freundlich and Dubinin-Radushkevich (D-R)). It was found that the maximum biosorption capacity and the removal efficiency (%) were as 243.9024 mgg(-1) and 91.38%, respectively. The biosorption of MB onto the ACLPF was chemical biosorption due to the activation energy (E-a) to be 42.63 kJmol(-1), and the process was endothermic (Delta H-0=61.4163 kJmol(-1)), feasible and spontaneous (Delta G(0)= -7.0278 kJmol(-1) at 318 K and Delta S-0 =0.1707 kJmol(-1)K(-1)) thermodynamically. The novelty of this study is that besides obtained and characterized the activated carbon (ACLPF) from the non-living LPF at the first time, the discussions on the biosorption capability of the ACLPF for the removal of MB dye from aqueous media are included in this paper.
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, Erkan
Catalase 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.
Characterization and Investigation of Natural Clay Performance for Methylene Blue Removal: Results of the Adsorption Isotherm, Kinetic and Thermodynamic Studies
(Polish Society Magnesium Research, 2024) Aybar, Nesegul; Kul, Ali Riza
In this study, Van-Ba & scedil;kale (VB) clay was used for removal of Methylene Blue (MB) dye. The characterization of VB clay was carried out with the Fourier transform infrared spectra (FTIR), Brunauer-Emmett-Teller (BET), and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analysis. The BET surface area was measured as 11.983 m2/g. The FTIR spectra indicated the functional groups which represented the Si-H bond, N-H bond, N-O bond and Si-C stretching vibrations. The SEM-EDX analysis of VB clay showed that its composition consisted of 61.45% O, 25.70% Si, 5.89% Al, 2.82% K, 2.28% Na, 0.97% Fe, and 0.89% Ca by weight. The effects of removal, i.e. parameters pH (2-7), temperature (298-318 K), initial concentration (10-50 mg L-1) adsorbent dosage (0.2-3.0 g L-1), and contact time on adsorption, were investigated. The data obtained were entered into the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models, and it was demonstrated that the correlation coefficient values for the Freundlich isotherm model were higher than for the other isotherm models. The pseudo second order (PSO) kinetic model was a better choice for the removal of MB than the pseudo first order (PFO) and intraparticle diffusion (IPD) kinetic models. Negative Gibbs free energy values obtained from thermodynamic calculations show that adsorption occurs spontaneously. The free energy of D-R adsorption calculated using the D-R isotherm was less than 8 kJ mol(-1), indicating that the process was physical adsorption. The activation energy (EA) of this process was 29.21 kJ mol(-1) which confirmed the fact that the process was physical adsorp
Comparative Research of Isotherm, Kinetic, and Thermodynamic Studies for Neutral Red Adsorption by Activated Carbon Prepared From Apple Peel
(Springer int Publ Ag, 2023) Kul, Ali Riza; Koyuncu, Huelya; Turan, Aysenur; Aldemir, Adnan
In this study, activated carbon (AC) obtained with apple peel was used for removal of Neutral Red (NR) from aqueous solutions. The characterization of AC was evaluated with the Brunauer-Emmett-Teller (BET), Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analyses. Isotherm, kinetic, and thermodynamic parameters were determined for NR removal with AC. Eighteen isotherm models and eight kinetic models were analyzed for three temperatures and six initial dye concentrations. The experimental data best agree with the Langmuir model among the isotherm models, and the maximum adsorption capacity (q(m)) was calculated 142.857 mg/g at 318 K. It was determined that the pseudo-second-order (PSO) model was the best choice among the kinetic models with the highest correlation coefficients. The removal percentage of NR dye with AC obtained 82.13%, 84.79%, and 87.20% for 120 mg/L initial dye concentration at 298 K, 308 K, and 318 K, respectively. The negative free energy, enthalpy, and entropy values of adsorption obtained - 6386 J/mol, 46280 J/mol, and 165.48 J/mol.K for 20 mg/L NR concentration at 318 K, respectively. The results of this separation process shown spontaneous essence, and workability coinciding with the negative free energy and activation energy was found 13.651 kJ/mol. The assessment of the isotherm, kinetic, and thermodynamic results were evaluated with error functions. The highest correlation coefficient (R-2) values and the lowest sum of squares (SS), sum of the square of error (SE), and mean square of error (MSE) values were determined with Langmuir isotherm and PSO kinetic models. This research showed that AC prepared from biomass can be used effectively for wastewater treatment using adsorption technique.
Comparison of Acid Blue 25 Adsorption Performance on Natural and Acid-Thermal Co-Modified Bentonite: Isotherm, Kinetics and Thermodynamics Studies
(Pamukkale Univ, 2020) Aldemir, Adnan; Kul, Ali Riza
In the present study, natural bentonite and acid-thermal co-modified bentonite were utilized for Acid Blue 25 (AB25) removal. The adsorption experiments were executed at the temperature values of 298K, 308K and 318K. According to the results, Freundlich isotherm becomes more convenient model compared with Langmuir and Temkin model. Freundlich model coefficients rise when the temperature increases. Kinetic coefficients were calculated by pseudo first order (PFO) and pseudo second order (PSO) models. Coefficients of R2 evaluated were higher than 0.99 with experimental and obtained qe values close to each other explained that this process fits PSO kinetic model. The concentration of AB25 elevates from 30 to 80 mg/L adsorption capacity onto natural, acid-thermal co-modified bentonite increases from 8.36 to 27.00 mg/g and 9.30 to 29.09 mg/g for 298 K, respectively. Absolute values of free energy of AB25 onto natural and acid-thermal co-modified bentonite changes from 4.065 kJ/mol to 8.586 kJ/mol, respectively. Enthalpy values of AB25 onto natural and acid-thermal co-modified bentonite changes from 5.483 kJ/mol to 11.249 kJ/mol and entropy values of AB25 on natural and acid-thermal co-modified bentonite changes from 4.759 J/mol K to 8.940 J/mol K, respectively. It was also found that modified bentonite has higher adsorption capacity than natural bentonite.
Comparison of Methylene Blue Adsorption Performance on Natural, Thermal and Acid Modified Kaolin: Isotherm, Kinetics and Thermodynamics Studies
(Parlar Scientific Publications (p S P), 2019) Kul, Ali Riza; Aldemir, Adnan
Dyes in the industrial wastewaters such as textile, food and cosmetic are the one of major water pollution source. In this study natural, thermal and acid modified kaolin have been utilized as adsorbent for the removal of methylene blue (MB) which is one of the widely used dye in the industry, from aqueous solution within a batch process. Adsorption experiments were performed at three different temperatures (298, 308, 318K). Based on the experimental data Freundlich isotherm model better than the Langmuir model. Freundlich model coefficients increase as the temperature increases, indicating that adsorption is favorable at higher temperature. The kinetic data were analyzed using pseudo first order and pseudo second order models. Adsorption of the MB on kaolin at the different conditions was best fit the pseudo second order model. Kinetic constants are closer to the both temperatures and initial concentrations and qe values are increases with increasing concentration of MB. The values of activation parameters such as free energy (Delta G), enthalpy (Delta H) and entropy (Delta S) were determined. Thermodynamic parameters indicates that the adsorption process is physisorption, endothermic and increased randomness at the solid-solute interface with the high affinity of the kaolin for the MB. Initial dye concentration increases from 25 to 75 mg/L, the adsorption capacity of dye onto natural, thermal modified and acid modified kaolin from 5.03 to 20.29 mg/g, 6.66 to 23.89 mg/g and 7.16 to 25.57 mg/g, respectively. It was also found that acid modified kaolin has a higher adsorption capacity compared to that of natural or thermal kaolin. The results indicate that kaolin could be interesting alternative material with respect to more costly adsorbents used for dye removal.
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, Yunus
The 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.
Computer Assisted Training on Mathematics Lesson for the 6th Grade Students on Azerbaijan Middle Schools
(Elsevier Science Bv, 2015) Bashirov, Novruz; Alekberova, Aynure; Kul, Ali Riza; Mustafayeva, Jale; Chiyaneh, Akbar Barati
In this study constituting a computer program was taken as basic for in Azerbaijan secondary schools 6th class students well understanding Math and personal development Computer program was prepared in HTML language. As Website, it was brought into a useful form for whole students in all school. Website contains whole subjects of 6th class Math book. The students login and choose the subject and learn. After than solve the problems about with subject. After the paragraphs containing some subjects 15 exam questions were put for the students check himself. After solving this problem, computer program evaluate student's knowledge 5 grades. This evoking big concern in the students was present to Ministry of Education for it was used in whole at schools in Azerbaijan. (C) 2015 The Authors. Published by Elsevier Ltd.
Copper Removal From Wastewater Using Natural Pumice
(Health & Environment Assoc, 2015) Kul, Ali Riza; Alkan, Salih; Ocak, Sevda; Benek, Veysel
This study was conducted on the pumice supplied from the Van Province, Turkey. The physicochemical properties of CuCl2 at pH 5 were studied and the analyses were performed at a temperature of 308 degrees K at various concentrations (75 ppm, 100 ppm, 125 ppm) of Cu(II). In this study, we aimed to investigate the adsorption behavior between the Van pumice and Cu(II).
Equilibrium and Kinetic Studies for the Sorption of 3-Methoxybenzaldehyde on Activated Kaolinites
(Elsevier Science Bv, 2007) Koyuncu, Hulya; Kul, Ali Riza; Yildiz, Nuray; Calimli, Ayla; Ceylan, Hasan
The 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 303-333 K 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 (Delta G), the enthalpy (Delta H) and the entropy change of sorption (Delta 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 (k(a) and k(d)) 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 K-geo (k(a)/k(d)) from geometric approach. (c) 2006 Elsevier B.V. All rights reserved.
Equilibrium and Kinetic Studies of the Adsorption of Zn(Ii) Ions Onto Natural and Activated Kaolinites
(Sage Publications inc, 2009) Kul, Ali Riza; Caliskan, Necla
The removal of Zn(II) ions from aqueous solution was studied using natural, thermally-activated and acid-activated kaolinite samples at different temperatures. The linear Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption equations were applied to describe the equilibrium isotherms. The Langmuir constants for natural kaolinite were found to be negative whereas, for the other samples, the isotherm models gave a good fit. In addition, the pseudo-first-order and pseudo-second-order models were used to determine the kinetic data. The experimental data were well fitted by the pseudo-second-order kinetic model. Thermodynamic parameters such as the enthalpy (Delta H-0), Gibbs' free energy (Delta G(0)) and entropy (Delta S-0) were calculated for natural, thermally-activated and acid-activated kaolinite. These values showed that the adsorption of Zn(II) ions onto activated kaolinite was controlled by a physical mechanism and occurred spontaneously The process of adsorption was favoured at high temperatures, with the adsorption capacity of the acid-activated kaolinite being greater relative to that of natural and thermally-activated kaolinite at various temperatures.
Heavy Metal Exposure of Workers Working at Petroleum Products Filling Stations and Its Effects on Oxidative Stress
(Parlar Scientific Publications (p S P), 2020) Atasoy, Nurhayat; Komuroglu, Ahmet Ufuk; Yucel, Ufuk Mercan; Kul, Ali Riza; Gursoy, Tulay
Petroleum products increase oxidative stress and inflammation due to its particulate content. This study aims to determine the levels of heavy metals (zinc, lead, cadmium, chromium) and to measure level of reduced glutathione and enzyme activity of superoxide dismutase in serum and hair specimens of workers (n=50, research group) employed in petroleum products filling stations in Van province. The control group (n=25) was selected working in the office and compared with the research group. Heavy metal levels in hair and serum specimens were determined by using the inductively matched plasma optical emission spectrometry instrument and serum enzyme levels were determined by using spectrophotometric methods. Zinc, lead, cadmium and chromium metal levels were higher in the research group than healthy controls. In addition, reduced glutathione level and superoxide dismutase enzyme activity decreased due to metal exposure and oxidative stress occurred in the research group. Smoking contributed to the exposure of amount of the metals. In research group, positive correlations were found between metal exposures and life span/term of employment. In addition, with the increased life span and term of employment, metal exposure increased and antioxidant enzyme levels decreased. This study shows that workers employed in stations are exposed to heavy metal toxicity and cause oxidative stress.