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Öğe Batch removal of chromium(VI) from aqueous solution by Turkish brown coals(ELSEVIER SCI LTD, 2007) Arslan, Gulsin; Pehlivan, ErolThe ability of using low-rank Turkish brown coals (Ilgin: BC1, Bey ehir: BC2, and Ermenek: BC3) to remove Cr(VI) from aqueous solutions was studied as a function of contact time, solution pH, temperature, concentration of metal solutions and amount of adsorbent. Their sorption properties were compared with the activated carbon from Chemviron (AQ-30). Adsorption of Cr(VI) uptake is in all cases pH-dependent showing a maximum at equilibrium pH values between 2.0 and 3.2, depending on the biomaterial, that correspond to initial pH values of 2.3 units for BC1, 3.0 units for BC2 and 3.2 units for BC3 and AQ-30. Batch equilibrium tests showed that the Cr(VI) removal was fitted with Freundlich isotherm and the adsorption reached equilibrium in 80 min. It was proceeding effectively into a short acid pH interval (2.0-3.2) where processes of Cr(VI) sorption are maximized. It was observed that the maximum adsorption capacity of 11.2 mM of Cr(VI)/g for Ilgin (BC1), 12.4 mM of Cr(VI)/g for Beysehir (BC2), 7.4 mM of Cr(VI)/g for Ermenek (BC3) and 6.8 mM of Cr(VI)/g for activated carbon (AQ-30) was achieved at pH of 3.0. The rise in temperature caused a slight decrease in the value of the equilibrium constant (K-c) for the sorption of Cr(VI) ion. The Cr(VI) sorption capacities of Bey ehir and Ilgin brown coals were the same. Ermenek brown coals and activated carbon (AQ-30) showed a similar sorption capacity. (C) 2006 Elsevier Ltd. All rights reserved.Öğe Characteristics of corneal lens chitin in dragonfly compound eyes(ELSEVIER SCIENCE BV, 2016) Kaya, Murat; Sargin, Idris; Al-jaf, Ivan; Erdogan, Sevil; Arslan, GulsinChitin in the compound eyes of arthropods serves as a part of the visual system. The quality of chitin in such highly specialised body parts deserves more detailed examination. Chitin in the corneal (ommatidial) lenses of dragonfly (Sympetrum fonscolombii) compound eyes was isolated by using the classical chemical method. The chitin content of the corneal lenses was determined to be quite high (20.3 +/- 0.85%). The FT-IR analysis showed that corneal lens chitin was in the alpha-form as found in all arthropod species where mechanical strength is required. The surface morphology analysis by scanning electron microscopy revealed that the outer part of corneal lenses consisted of long chitin fibrils with regular arrays of papillary structures while the smoother inner part had concentric lamellated chitin formation with shorter chitin nanofibrils. Chitinase enzymatic digestion studies, elemental analysis results and the degree of acetylation value showed the purity of chitin samples from corneal lens. The maximum degradation temperature value of the corneal lens chitin was observed at 369.2 degrees C. X-ray analysis revealed that corneal lens chitin has high crystallinity index; 96.4%. Identification of chitin found in ommaditia of insect compound eyes can provide insights into insect vision and chitin-based optical material design studies. (C) 2016 Elsevier B.V. All rights reserved.Öğe Chitosan/sporopollenin microcapsules: Preparation, characterisation and application in heavy metal removal(ELSEVIER SCIENCE BV, 2015) Sargin, Idris; Arslan, GulsinUse of natural polymers as biosorbents for heavy metal removal is advantageous. This paper reports a study aiming to design a novel biosorbent from two biomacromolecules; chitosan, a versatile derivative of chitin, and sporopollenin, a biopolymer with excellent mechanical properties and great resistance to chemical and biological attack. Chitosan/sporopollenin microcapsules were prepared via cross-linking and characterised by employing scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. Sorption performance of the microcapsules and the plain chitosan beads were tested for Cu(II), Cd(II), Cr(III), Ni(II) and Zn(II) ions at different metal ion concentration, pH, amount of sorbent, temperature and sorption time. The adsorption pattern followed Langmuir isotherm model and the sorption capacity of the chitosan/sporopollenin microcapsules was found to be Cu(II): 134, Cd(II): 0.77, Cr(III): 0.99, Ni(II): 0.58 and Zn(II): 0.71 mmol g(-1). Plain chitosan beads showed higher affinity for the ions; Cu(II): 1.46, Cr(III): 1.16 and Ni(II): 0.81 mmol g(-1) but lower for Cd(II): 0.15 and Zn(II): 0.25 mmol g(-1). Sporopollenin enhanced Cd(II) and Zn(II) ions sorption capacity of the chitosan microcapsules. Chitosan/sporopollenin microcapsules can be used in Cd(II) and Zn(II) metal removal. (C) 2015 Elsevier B.V. All rights reserved.Öğe Determination of heavy metals and metals levels in five fish species from Isikli Dam Lake and Karacaoren Dam Lake (Turkey)(SPRINGER, 2012) Kalyoncu, Leyla; Kalyoncu, Hasan; Arslan, GulsinThe concentrations of heavy metals and metals (Zn, Pb, Bi, Cd, Ni, Co, Fe, Mn, Mg, Cu, Cr, Ca, Sr, Na, Li, K) were measured in muscle of five species Cyprinus carpio (from IAYA +/- klA +/- dam), Scardinius erythrophthalmus (from IAYA +/- klA +/- dam), Tinca tinca (from IAYA +/- klA +/- dam), C. carpio (from Karacaoren dam), Carassius carassius (from Karacaoren dam) caught from IAYA +/- klA +/- and Karacaoren. The highest metal was Na (466.95 mu g/g) in C. carassius, while the lowest levels were Fe (0.37 mu g/g) and Cu (0.37 mu g/g) in C. carpio from IAYA +/- klA +/- dam. The mean concentrations mu g/g d.w. some of heavy metals in muscle of C. carpio (from IAYA +/- klA +/- dam), S. erythrophthalmus (from IAYA +/- klA +/- dam), T. tinca (from IAYA +/- klA +/- dam), C. carpio (from Karacaoren dam), C. carassius ( from Karacaoren dam) were as follows: Cd 2.00-2.10-1.95-2.06-2.27, Zn 4.36-2.64-13.13-13.33-24.47, Pb 1.65-1.24-1.90-2.37-2.41, Co 2.46-2.37-2.48-2.58-2.80, Mg 138.51-154.35-218.59-204.58-202.16, Fe 0.37-2.62-3.17-3.01-12.33, respectively.Öğe Determination of Some Metal Levels in Muscle Tissue of Nine Fish Species from Beysehir Lake, Turkey(CENTRAL FISHERIES RESEARCH INST, 2012) Ozparlak, Haluk; Arslan, Gulsin; Arslan, EmineConcentrations of some metals were determined in muscle tissues of nine fish species from Beysehir Lake, Turkey by using atomic absorption spectrophotometer. Most of metal levels in Alburnus akili were higher than those of other fish species as followings: Pb 5.25 mg kg(-1), Cd 4.00 mg kg(-1), Zn 23.75 mg kg(-1), Ni 4.01 mg kg(-1), Cr 24.45 mg kg(-1), Mn 17.53 mg kg(-1), Co 5.90 mg kg(-1), Mg 283.06 mg kg(-1), Sr 27.40 mg kg(-1), K 514.09 mg kg(-1) and Li 49.38 mg kg(-1). The highest concentrations of Cu and Ca were determined in Scardinius erythrophthalmus as 2.68 mg kg(-1) and 538.83 mg kg(-1) respectively. The highest concentrations of Bi and Na were measured in Gobio gobio microlepidotus as 6.05 mg kg(-1) and 423.56 mg kg(-1) respectively. Maximum Fe (13.98 mg kg(-1)) content was determined in Tinca tinca compared to other species. Concentrations of Pb and Cd in the muscle tissue of all the fish species exceeded the tolerance levels of national and international guidelines but were below Provisional Tolerable Weekly Intake (PTWI) limits set by FAO/WHO. The contents of Ni, Cr and Mn in specimens were also higher than the tolerance levels of some guidelines. On the contrary, levels of Zn, Cu and Fe were below the limits of guidelines and PTWI.Öğe Determination of Trace Amounts of Cr(III) in Water Samples by Flame Atomic Absorption Spectrometry(BENTHAM SCIENCE PUBL LTD, 2012) Arslan, GulsinA fast and effective microextraction technique is proposed for the determination of trace amounts of Cr(III) in water samples, using ultrasound-assisted emulsification-microextraction (USAEME) followed by flame atomic absorption spectrometry (FAAS). In the proposed approach, sodium diethyldithiocarbamate trihydrate solution (NaDDTC(center dot)3H(2)O) was used as a chelating agent and chloroform was selected as extraction solvent. After determination of the most suitable solvent and extraction time, some effective parameters such as an extraction solvent volume, temperature, and pH were investigated and optimized. The optimized USAEME procedure used 100 mu L of chloroform, 20 min of extraction with no ionic strength adjustment at 50 degrees C and 5 min of centrifugation at 4000 rpm. The method was applied to the analysis of tap, well, dam on industrial waste water samples and the Trace Metals in Drinking Water standards CRM-TMDV. The detection limit for Cr(III) was 0.079 mu g L-1 with an enrichment factor of 95, and the relative standard deviation was 2.8-1.1% (n=8, c=500 mu g L-1). The proposed USAEME procedure has been demonstrated to be viable, simple, rapid and easy to use for the residue analysis separation of Cr(III).Öğe Differentiations of Chitin Content and Surface Morphologies of Chitins Extracted from Male and Female Grasshopper Species(PUBLIC LIBRARY SCIENCE, 2015) Kaya, Murat; Lelesius, Evaldas; Nagrockaite, Radvile; Sargin, Idris; Arslan, Gulsin; Mol, Abbas; Baran, TalatIn this study, we used Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), and scanning electron microscopy (SEM) to investigate chitin structure isolated from both sexes of four grasshopper species. FT-IR, EA, XRD, and TGA showed that the chitin was in the alpha form. With respect to gender, two main differences were observed. First, we observed that the quantity of chitin was greater in males than in females and the dry weight of chitin between species ranged from 4.71% to 11.84%. Second, using SEM, we observed that the male chitin surface structure contained 25 - 90nm wide nanofibers and 90 - 250 nm nanopores, while no pores or nanofibers were observed in the chitin surface structure of the majority of females (nanofibers were observed only in M. desertus females). In contrast, the elemental analysis, thermal properties, and crystalline index values for chitin were similar in males and females. Also, we carried out enzymatic digestion of the isolated chitins using commercial chitinase from Streptomyces griseus. We observed that there were no big differences in digestion rate of the chitins from both sexes and commercial chitin. The digestion rates were for grasshoppers' chitins; 88.45-95.48% and for commercial chitin; 94.95%.Öğe Effect of glutaraldehyde cross-linking degree of chitosan/sporopollenin microcapsules on removal of copper(II) from aqueous solution(DESALINATION PUBL, 2016) Sargin, Idris; Arslan, GulsinBio-based sorbents, especially cross-linked chitosan, have been widely used in heavy metal removal. Type of cross-linking agent and degree of cross-linking largely affect metal sorption behaviour of chitosan-based sorbents. This study describes the preparation of chitosan/sporopollenin (CS) microcapsules cross-linked with different amount of glutaraldehyde (GA)/chitosan ratios. The microcapsules were modified by the incorporation of 0.3, 0.9 and 1.5mL of GA solution (in water 25% v:v) for 1.50g of chitosan. A protected cross-linking method was used for the preparation of the CS/GA microcapsules by the reaction of the microcapsules with Cu(II) as the protector. Scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis were employed for the microcapsules characterization. The adsorption performance of the microcapsules was studied for the removal of Cu(II) at different concentration, contact time, amount of adsorbent, temperature and pH. The maximum Cu(II) removal values were 88.9, 100.4 and 80.7mgg(-1) by 0.3, 0.9 and 1.5mL of GA impregnated CS microcapsules, respectively. The equilibrium adsorption isotherm data of the microcapsules exhibited a better fit to the Freundlich isotherm model. Affinity of the CS microcapsules for Zn(II), Cd(II), Ni(II) and Cr(III) in presence of Cu(II) was also investigated. GA/chitosan ratio affected the metal sorption performance and physicochemical properties of the microcapsules. The results revealed that CS microcapsules that were cross-linked with 0.9mL of GA solution had better Cu(II) ion sorption capacity and can be cost-effective sorbents in water treatment.Öğe Efficiency of chitosan-algal biomass composite microbeads at heavy metal removal(ELSEVIER SCIENCE BV, 2016) Sargin, Idris; Arslan, Gulsin; Kaya, MuratA new chitosan/algal (Cladophora sp.) composite microbead was produced and used in removal of heavy metal ions. Bleached algal biomass was incorporated into the chitosan matrix through cross-linking with glutaraldehyde. Fourier transform infrared spectroscopy analysis demonstrated that bleached algal biomass consisted of mainly cellulosic residues. Scanning electron microscopy images exhibited that algal particles were immobilised in the polymeric matrix. Sorption capacity of the microbeads was determined; Cd(II): 0.240, Cr(III): 1.128, Cu(II): 1.059, Ni(II): 0239 and Zn(II): 0310 mmol g(-1). The microbeads with bleached algal biomass exhibited higher sorption capacity for Cd(II) and Zn(II) ions than the plain glutaraldehyde cross-linked chitosan microbeads, demonstrating that the contribution of the algal biomass to the sorption. Equilibrium, kinetic and thermodynamic evaluation of the experimental data was performed. The findings revealed that chitosan-algal composite microbeads can be used in heavy metal removal. (C) 2015 Elsevier B.V. All rights reserved.Öğe Facilitated transport of Cr(III) through activated composite membrane containing di-(2-ethylhexyl)phosphoric acid (DEHPA) as carrier agent(ELSEVIER, 2009) Arslan, Gulsin; Tor, Ali; Cengeloglu, Yunus; Ersoz, MustafaThe facilitated transport of chromium(III) through activated composite membrane (ACM) containing di-(2-ethylhexyl) phosphoric acid (DEHPA) was investigated. DEHPA was immobilised by interfacial polymerisation on polysulfone layer which was deposited on non-woven fabric by using spin coater. Then. ACM was characterised by using scanning electron microscopy (SEM), contact angle measurements and atomic force microscopy (AFM). Initially, batch experiments of liquid-liquid distribution of Cr(III) and the extractant (DEHPA) were carried out to determine the appropriate pH of the feed phase and the results showed that maximum extraction of Cr(III) was achieved at a pH of 4. It Was also found that Cr(III) and DEHPA reacted in 1/1 molar ratio. The effects of Cr(III) (in feed phase), HCl (in stripping phase) and DEHPA (in ACM) concentrations were investigated. DEHPA concentration varies from 0.1 to 1.0M and it was determined that the transport of Cr(III) increased with the carrier concentration LIP to 0.8 M. It was also observed that the transport of Cr(III) through the ACM tended to increase with Cr(III) and HCl concentrations. The stability of ACM was also confirmed with replicate experiments. (C) 2008 Elsevier B.V. All rights reserved.Öğe Facilitated transport of Cr(III) through polymer inclusion membrane with di(2-ethylhexyl)phosphoric acid (DEHPA)(ELSEVIER, 2009) Tor, Ali; Arslan, Gulsin; Muslu, Harun; Celiktas, Ahmet; Cengeloglu, Yunus; Ersoz, MustafaIn this study, transport of Cr(III) through polymer inclusion membrane (PIM) with di(2-ethylhexyl)phosphoric acid (DEHPA) as carrier was reported. First, PIM was characterized by using FTIR and atomic force microscopy (AFM) techniques and contact angle measurements. Then, the effects of Cr(III) (in feed phase), HCI (in stripping phase) and DEHPA (in membrane) concentrations on the transport were investigated. DEHPA concentration varies from 0.25 to 0.5 M and it was determined that the transport of Cr(III) increased with the carrier concentration up to 0.4 M. It was also observed that the transport of Cr(III) through the PIM tended to increase with Cr(III) and HCI concentrations. According to the competitive transport of Cr(III), Cu(II) and Ni(II) through the PIM, the transport selectivity order was found as Cr(III)approximate to Cu(II)>Ni(II). The result from the transport of Cr(III) mixed with Cr(VI) also showed that flux of Cr(III)was not influenced by the presence of Cr(VI) in feed phase and no Cr(VI) transport through the PIM was determined. PIM had lower experimental Cr(III) flux than those of supported liquid membrane (SLM) and activated composite membrane (ACM) under the same experimental conditions. However, long-term stability of PIM and small difference between normalized flux for PIM and experimental SLM flux indicated that PIM could replace SLM for practical applications. (c) 2008 Elsevier B.V. All rights reserved.Öğe Facilitated transport of Cr(VI) through a novel activated composite membrane containing Cyanex 923 as a carrier(ELSEVIER, 2009) Arslan, Gulsin; Tor, Ali; Muslu, Harun; Ozmen, Mustafa; Akin, Ilker; Cengeloglu, Yunus; Ersoz, MustafaThis paper describes the facilitated transport of Cr(VI) through a novel Activated Composite Membrane (ACM) containing Cyanex 923 as a carrier. The ACM was prepared by immobilization of the Cyanex 923 on a polysulfone support by means of interfacial polymerisation. The prepared ACM was characterized by using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques and contact angle measurements. The effect of feed phase composition, carrier concentration of the casting solution and stripping phase composition on the transport of Cr(VI) was investigated. When the feed phase contained 1 X 10(-3) M Cr(VI) at pH 1.0, 99% of Cr(VI) was transported through the ACM (prepared with 3% carrier solution) by using 1 M NaOH as a stripping phase. Furthermore, Cr(VI) was preferably transported in the presence of various metal ions (i.e., Cr(III), Ni(II), Cu(II), Zn(II), Cd(II), Co(II), etc.) and sulphate and nitrate ions had no negative effect on the transport of Cr(VI). The results also showed that transport efficiency of the ACM was reproducible and it could be efficiently used in the long-term separation processes instead of supported liquid membrane (SLM). (C) 2009 Elsevier B.V. All rights reserved.Öğe Hexavalent chromium removal by magnetic particle-loaded micro-sized chitinous egg shells isolated from ephippia of water flea(ELSEVIER SCIENCE BV, 2019) Arslan, Gulsin; Sargin, Idris; Kaya, MuratModified chitin and magnetic particles are two important materials widely used in heavy metal removal studies. Loading of magnetic particles into conventional adsorbents has emerged as a recent convenient way to improve the properties of adsorptive materials. Compared to its deacetylated form chitosan, chitin has very limited use in removal of contaminants because of its insolubility in aqueous environments. This study reports an easy way to produce micro-sized chitin and gives details on loading of magnetic particles into micro-sized chitin to enhance the interaction of chitin with heavy metal contaminant; hexavalent chromium Cr(VI). Removal of Cr(VI) ions from the aquatic environments is of high importance considering its detrimental effects on human health. Chitin microcages that had been isolated from the ephippial eggs of Daphnia longispina (crustacean, water flea) were incorporated with magnetic particles. Chitin microcages and magnetic particles-loaded chitin microcages were tested in removal of Cr(VI) under different solution and operational parameters; adsorbent dosage, contact time, Cr(VI) ion concentration, pH and temperature. Magnetic particles-loaded chitin microcages yielded higher Cr(VI) removal performance under all the specified conditions; chitin microcages: 0.77 mmol/g and particles loaded chitin microcages: 1.29 mmol/g. (C) 2019 Elsevier B.V. All rights reserved.Öğe Interactions of bovine serum albumin with humic acid-Cu(II) aggregates in poly(hydroxyethylmethacrylate) cryogel column(ELSEVIER SCIENCE BV, 2016) Sargin, Idris; Arslan, Gulsin; Erzengin, MahmutUnderstanding the interactions of proteins with humic acid in different media is essential for many applications. This paper investigates the interactions of bovine serum albumin with humic acid-Cu(II) complexes in a poly(hydroxyethylmethacrylate) cryogel column. Humic aggregates were immobilized within the cryogenic matrix. Protein sorption studies were conducted at different temperature, ionic strength, protein concentration, pH and flow-rate. Protein adsorption increased at lower pHs (close to the isoelectric point of the protein; 4.7) and higher temperatures but decreased at higher ionic strength and flow-rates. Both electrostatic and hydrophobic interactions played roles in the sorptive behavior of the protein molecules. Isotherm analysis showed the monolayer protein adsorption onto humic molecules immobilized column. (c) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.Öğe Microfungal spores (Ustilago maydis and U. digitariae) immobilised chitosan microcapsules for heavy metal removal(ELSEVIER SCI LTD, 2016) Sargin, Idris; Arslan, Gulsin; Kaya, MuratDesigning effective chitosan-based biosorbents from unexploited biomass for heavy metal removal has received much attention over the past decade. Ustilago, loose smut, is a ubiquitous fungal plant pathogen infecting over 4000 species including maize and weed. This study aimed to establish whether the spores of the phytopathogenic microfungi Ustilago spores can be immobilised in cross-linked chitosan matrix, and it reports findings on heavy metal sorption performance of chitosan/Ustilago composite microcapsules. Immobilisation of Ustilago maydis and U. digitariae spores (from maize and weed) in chitosan microcapsules was achieved via glutaraldehyde cross-linking. The cross-linked microcapsules were characterised using scanning electron microscopy, FT-IR spectroscopy and thermogravimetric analysis. Sorption capacities of chitosan-U. maydis and chitosan-U. digitariae microcapsules were investigated and compared to cross-linked chitosan beads: Cu(II): 66.72, 69.26, 42.57; Cd(II): 49.46, 53.96, 7.87; Cr(III): 35.88, 49.40, 43.68; Ni(II): 41.67, 33.46, 16.43 and Zn(II): 30.73, 60.81, 15.04 mg/g, respectively. Sorption experiments were conducted as a function of initial metal ion concentration (2-10 mg/L), contact time (60-480 min), temperature (25,35 and 45 degrees C), amount of the sorbent (0.05-0.25 g) and pH of the metal solution. The microcapsules with spores exhibited better performance over the plain chitosan beads, demonstrating their potential use in water treatment. (C) 2015 Elsevier Ltd. All rights reserved.Öğe A new BODIPY/nanoparticle/Ni affinity system for binding of cytochrome c(ELSEVIER SCIENCE BV, 2015) Maltas, Esra; Kursunlu, Ahmed Nuri; Arslan, Gulsin; Ozmen, MustafaIn this study, 3,5-{Bis[4,4-difluoro, 8-(2,6-diethyl, 1,3,5,7-tetramethy1-4-bora-3a,4a-diaza-sindacene)]}benzoylchloride (BODIPY) was synthesized for the improving of a new immobilized metal affinity supporting material. Firstly, the synthesized BODIPY was immobilized on iron oxide superparamagnetic nanoparticles (SPIONs) and then, Ni(II) ions were chelated with the active terminals of BODIPY on nanoparticles surfaces to prepare an immobilized metal affinity (IMA) adsorbent for protein adsorption. The amount of BODIPY coated on SPIONs was about 29.7 mu M at 10 mg nanoparticles. 738 mu mol of Ni(II) ions were loaded to 10 mg of the SPIONs/BODIPY. The binding amount of cytochrome c was found to be 170 mu g to the SPIONs/BODIPY/Ni at pH 7.4. The binding amount of the molecules on SPIONs was analyzed by using UV-vis, fluorescence and atomic absorption spectroscopy. The characterization of the prepared surfaces was performed by FT-IR, SEM and TEM. (C) 2015 Elsevier B.V. All rights reserved.Öğe Preconcentrative separation of chromium(III) species from chromium(VI) by cloud point extraction and determination by flame atomic absorption spectrometry(SPRINGER WIEN, 2011) Yildiz, Zeynep; Arslan, Gulsin; Tor, AliWe describe a high-throughput technique for the determination of chromium species in water samples by flame atomic absorption spectrometry (FAAS) after preconcentrative separation of Cr(III) species from Cr(VI) by cloud point extraction (CPE) using diethyldithiocarbamate (DDTC) as the chelating agent and the nonionic surfactant Triton X-100 as the extractant. The Cr(III)-DDTC complex is extracted if the temperature is higher than the CPE temperature of Triton X-100, while Cr(VI) remains in the aqueous phase. The Cr(III) in the surfactant phase was analyzed by FAAS, and the concentration of Cr(VI) was calculated by subtraction of Cr(III) from total chromium which was directly determined by FAAS. The effect of pH, concentration of chelating agent, surfactant, and equilibration temperature were investigated. The detection limit for Cr(III) was 0.08 mu g L-1 with an enrichment factor of 98, and the relative standard deviation was 1.2% (n=3, c=100 mu g L-1). A certified reference material and several water samples were analyzed with satisfactory results.Öğe Preparation and characterisation of biodegradable pollen-chitosan microcapsules and its application in heavy metal removal(ELSEVIER SCI LTD, 2015) Sargin, Idris; Kaya, Murat; Arslan, Gulsin; Baran, Talat; Ceter, TalipBiosorbents have been widely used in heavy metal removal. New resources should be exploited to develop more efficient biosorbents. This study reports the preparation of three novel chitosan microcapsules from pollens of three common, wind-pollinated plants (Acer negundo, Cupressus sempervirens and Populus nigra). The microcapsules were characterized (Fourier transform infrared spectroscopy, thermo-gravimetric analysis, scanning electron microscopy and elemental analysis) and used in removal of heavy metal ions: Cd(II), Cr(III), Cu(II), Ni(II) and Zn(II). Their sorption capacities were compared to those of cross-linked chitosan beads without pollen grains. C. sempervirens-chitosan microcapsules exhibited better performance (Cd(II): 65.98; Cu(II): 67.10 and Zn(II): 49.55 mg g (1)) than the other microcapsules and the cross-linked beads. A. negundo-chitosan microcapsules were more efficient in Cr(III) (70.40 mg g (1)) removal. P. nigra-chitosan microcapsules were found to be less efficient. Chitosan-pollen microcapsules (except P. nigra-chitosan microcapsules) can be used in heavy metal removal. (C) 2014 Elsevier Ltd. All rights reserved.Öğe Preparation and characterization of novel polysulfone-red mud composite capsules for the removal of fluoride from aqueous solutions(ROYAL SOC CHEMISTRY, 2016) Kazak, Omer; Tor, Ali; Akin, Ilker; Arslan, GulsinThis study is the first investigation on the encapsulation of red mud by a polysulfone matrix through a phase inversion process to obtain composite capsules for the removal of fluoride from aqueous solutions. This approach facilitates the use of red mud in batch and column sorption techniques because the polysulfone matrix renders efficient aqueous diffusivity. The produced polysulfone-red mud composite capsules (red mud@ PSF capsules) were characterized by using FT-IR, TGA, SEM and BET. The batch sorption experiments showed that the red mud@ PSF capsules prepared with a mass ratio of red mud to polysulfone (1 : 1, g : g) provided maximum removal at equilibrium pH between 3.2 and 4.7. The batch equilibrium was attained within 30 minutes and sorption behavior was governed by pseudo-second-order kinetics together with intra-particle diffusion. Isotherm analyses showed that the Freundlich and Redlich-Peterson isotherm models better represented the sorption data, which was confirmed by the Chi-square (chi(2)) statistical test. The capsules could be reused for at least two sorption-desorption cycles without significant change in their sorption efficiency. Batch and column experiments on a real mineral water sample fortified with fluoride (final concentration 10 mg L-1) showed that the red mud@ PSF capsules could be applied to real water samples to reduce the fluoride concentration below the limit value (1.5 mg L-1) recommended by the World Health Organization (WHO) for drinking water.Öğe Preparation of new polysulfone capsules containing Cyanex 272 and their properties for Co(II) removal from aqueous solution(ELSEVIER SCI LTD, 2015) Kazak, Omer; Tor, Ali; Akin, Ilker; Arslan, GulsinIn this study, new polysulfone capsules containing Cyanex 272 (Cyanex 272@PSF capsules) were prepared by phase inversion technique for the sorption of Co(II) from aqueous solution. The characterization of the Cyanex 272@PSF capsules which were performed by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and thermal gravimetric analysis (TGA) indicated that Cyanex 272 was successfully encapsulated by polysulfone. For the Cyanex 272@PSF capsules having the highest sorption efficiency, the encapsulation efficiency was determined as 7.2%. The batch sorption experiments showed that removal of Co(II) from aqueous solutions occurred through the cation-exchange and chelation mechanisms and maximum removal was achieved at an initial pH of 8.0 (final pH of 5.9). The Cyanex 272@PSF capsules produced with dispersed phase containing 2.0% of Cyanex 272 (by wt.) provided the highest Co(II) removal. The sorption equilibrium time was attained within 120 min. By confirming the non-linear Chi-square (x(2)) statistical test, Langmuir isotherm model was the best fit model. Langmuir sorption capacity (Q(o)) and sorption constant (b) were 2.014 mg/g and 0.281 L/mg, respectively. The regenerated capsules could be used three times with no change in their sorption capacities. Based on the experiments performed at initial pH of 8.0 for other metal ions, including Ni(II), Pb(II) and Cd(II), sorption ability of Cyanex 272@PSF capsules was in the order: Co(II) approximate to Ni(II)>Cd(II)>Pb( II). Consequently, Cyanex 272@PSF capsules have potential for removing Co(II) from aqueous solutions. (C) 2015 Elsevier Ltd. All rights reserved.
