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Öğe Adsorption of Cu(II) From Aqueous Solution by Using Modified Fe3O4 Magnetic Nanoparticles(Elsevier, 2010) Özmen, Mustafa; Can, Keziban; Arslan, Gülsin; Tor, Ali; Çengeloğlu, Yunus; Ersöz, MustafaIn this study, surface modification of Fe3O4 nanoparticles (Fe3O4-NPs) was carried out with 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA). The obtained modified-NPs (GA-APTES-NPs) were evaluated for Cu(II) removal from water by adsorption. First, Fe3O4-NPs were synthesized by co-precipitation of Fe2+ and Fe3+ with Fe2+/Fe3+ in a ratio of 1.75 in an ammonia solution, then surface of Fe3O4-NPs was modified with APTES and GA. The morphology and properties of the NPs were examined by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA) and magnetization measurement. The batch experiments showed that modified-NPs can be effectively used to remove Cu(II) from water. Adsorption equilibrium was achieved in 15 min. The adsorption of Cu(II) by GA-APTES-NPs strongly depends on the pH of the solution. Maximum removal of Cu(II) was obtained at pH between 4.0 and 5.3. The isotherm analysis indicated that the sorption data can be represented by both Langmuir and Freundlich isotherm models. The regeneration studies also showed that GA-APTES-NPs could be re-used for the adsorption of Cu(II) from aqueous solutions over three cycles without change in the sorption capacity and magnetization properties.Öğe Biocompatible hydrogels: synthesis, swelling property and solvent effect on gelation(Selçuk Üniversitesi Mühendislik Fakültesi, 2013) Ulaşan, Mehmet; Çengeloğlu, Yunus; Yavuz, Mustafa SelmanBiocompatible hydrogels have an increasing interest in recent years. Poly (2-hydroxyethyl methacrylate, PHEMA) is widely studied with its biocompatible property. In this study, we have shown the gelation conditions to produce PHEMA hydrogels which have an excellent hydrogel property. Since dissolution forces by solvents are so important in gelation process, we studied the effect of solvent combination of acetone and water mixture in detail. As a result of investigation, the available acetonewater ratio limits were stated in order to obtain PHEMA hydrogels. The swelling property of PHEMA hydrogel was also shown. In our study, PHEMA samples imbibe water as much as five times of their own weight.Öğe Biocompatible multi-walled carbon nanotube-CdTe quantum dot-polymer hybrids for medical applications(ELSEVIER SCIENCE BV, 2015) Başlak, Canan; Kars, Meltem Demirel; Karaman, Mustafa; Kuş, Mahmut; Çengeloğlu, Yunus; Ersöz, MustafaHerein we report the synthesis of polymer coated quantum dots (QDs)-carbon nanotube composite material with high biocompatibility and low cellular toxicity. The synthesized multi-walled carbon nanotube (MWCNT)-QD-(-poly(glycidyl methacrylate)) (pGMA) hybrids were characterized using X-ray photoelectron spectroscopy, laser scanning confocal microscopy, transmission electron microscopy and scanning electron microscopy. The results showed that quantum dots were well-distributed on nanotube surfaces in high density. The toxicological assessments of QDs and MWCNT-QD-polymer hybrids in human mammary carcinoma cells and their fluorescence imaging in living cell system were carried out. MWCNT-QD-polymer hybrids possess intense red fluorescence signal under confocal microscopy and good fluorescence stability over 6-h exposure in living cell system. The toxicity comparison of QDs and MWCNT-QD-polymer hybrids has shown that the existence of PGMA thin coating on MWCNT-QD hybrid surface decreased the cellular toxicity and increased biocompatibility. (C) 2014 Elsevier B.V. All rights reserved.Öğe A comparative study on fluorescence quenching of CdTe nanocrystals with a serial of polycyclic aromatic hydrocarbons(ELSEVIER SCIENCE BV, 2014) Başlak, Canan; Kuş, Mahmut; Çengeloğlu, Yunus; Ersöz, MustafaWe report sensing different polycyclic aromatic hydrocarbons (PAHs) with colloidal CdTe nanocrystals. The effect of molecular structure on quenching rate for 2-hyroxy-1-naphthaldehyde (2H-1N), 9,10-phenanthraquinone (PQ), 9-anthracenecarboxaldehyde (9-AC) and quinoline (Q) is presented. The quenching rate constants are observed to be strongly dependent on the molecular structure. PQ consisting of two carbonyl groups, shows the highest rate constant while Q shows the worst one. Both static and dynamic quenching are simultaneously observed for PQ and 2H-1N. Therefore extended Stern-Volmer equations are used to calculate rate constants. Results showed that dynamic quenching is a dominant process. The rate constants for PQ 2H-1N, 9-AC and Q are calculated to be 64.84, 10.73, 10.66 and 1.85 respectively. (C) 2014 Elsevier B.V. All rights reserved.Öğe The Effect of Accompanying Anion and the Competitive Transport of Ni(Ii) and Fe(Iii) Through Polysulfone Membranes(Marcel Dekker Inc, 2003) Kır, Esengül; Tor, Ali; Çengeloğlu, Yunus; Ersöz, MustafaThe effect accompanying anion on the transport of Ni2+ and competitive transport of Ni2+ and Fe3+ ions through charged polysulfone or polysulfone polyester-supported cation exchange membranes was studied under Donnan dialysis conditions. In the Donnan dialysis process, two electrolyte solutions were separated by ion permeable membrane, the one side (feed solution) initially containing metal salts or their mixtures, the other is HCl and no external potential field is applied. The transport of metal ions through membranes was correlated with the efficiency factor (EF) values as well as with fluxes and depended on the interaction between the fixed groups in the membrane and the metal ions. The EF value of Ni2+ as a single as well as mixture state was higher than that of Fe3+ for both types of membranes. The effect of accompanying anion on the transport of Ni2+ was found to be in the following order of Cl- > NO3- > SO4-2, and the results were correlated with the EF values, as well as with the membrane structure.Öğe Effect of Temperature on Separation of Purine and Pyrimidine Bases on Novel Chelating Resin(Elsevier Science Bv, 2002) Ayar, Ahmet; Mercimek, Bedrettin; Kara, Hüseyin; Çengeloğlu, YunusThe novel chelating resin poly-bis [4-(4'-biphenyl)oxamidine]-diaminoglyoxime (PLH2) has been modified as ligand-exchange material with Co(II). The possibility of using PLH2 as ligand exchanger in the chromatographic separation of nucleic acid bases and nucleosides has been studied at various temperatures. PLH2 offers the advantage of combining high sorption capacity with high selectivity for the ligands. It has a strong driving force for ligand sorption. Ligand-exchange chromatography on Co(II)-loaded functionalized PLH2 can be a useful alternative method for separation of nucleic acid bases and nucleosides.Öğe Facilitated transport of Cr(III) through activated composite membrane containing di-(2-ethylhexyl)phosphoric acid (DEHPA) as carrier agent(ELSEVIER, 2009) Arslan, Gülşin; Tor, Ali; Çengeloğlu, Yunus; Ersöz, 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, Gülşin; Muslu, Harun; Çeliktaş, Ahmet; Çengeloğlu, Yunus; Ersöz, 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, Gülşin; Tor, Ali; Muslu, Harun; Özmen, Mustafa; Akın, İlker; Çengeloğlu, Yunus; Ersöz, 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 Increasing the phenol adsorption capacity of neutralized red mud by application of acid activation procedure(ELSEVIER SCIENCE BV, 2009) Tor, Ali; Çengeloğlu, Yunus; Ersöz, MustafaThe objective Of this Study was to investigate the removal of phenol from aqueous solution by using acid activated red mud in batch adsorption experiments. The Study was carried out as functions of pH, contact time, activated red mud dosage and initial phenol concentration. It was found that the maximum removal was obtained at pH below 8 and the adsorption equilibrium time was 10 h. Adsorption was followed the pseudo second-order kinetic model. According to the coefficient of determination and non-linear regression analysis carried Out by Chi-square test, the Langmuir isotherm better represented the adsorption data in comparison to the Freundlich isotherm. The phenol adsorption capacity of the activated red mud (8.156 mg/g) was found to be higher than that of the neutralized red mud (4.127 mg/g) at pH 6 and 25 +/- 1 degrees C. Negative Delta G(0) value (-22.692 kJ/mol) indicated that the adsorption of phenol onto the activated red Mud was spontaneous and feasible process.Öğe The Membrane Potentials of Periderm and Cuticular Membranes(Scientific Technical Research Council Turkey, 2002) Şahin, Aygül; Çengeloğlu, Yunus; Ersöz, MustafaThe membrane potentials of periderm and cuticular membranes were measured with KCl and NaCl solution using Ag/AgCI electrodes. For the electromotive force (emf) measurements, the concentration in both compartments were brought to equilibrium with the 0.01 M concentration of KCI or NaCl solution, then the one side was kept constant and the other side changed. The estimation of the Dorman potential contribution to the membrane potential was carried out by taking into account the fixed charge concentration, C-x, value. From these measurements electrochemical characterization of the asymmetry and surface layers of the periderm and cuticular membranes can be described.Öğe Polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) in wastewater samples from the sewage system of Konya-Turkey(Parlar Scientific Publications (P S P), 2003) Tor, A.; Çengeloğlu, Yunus; Aydın, Mehmet Emin ; Ersöz, Mustafa; Wichmann, H.; Bahadır, MüefitIn this work, PCB and PAH analyses are performed on wastewater samples from the sewage system of Konya, Turkey. The analytical method includes a liquid-liquid extraction, a clean-up procedure and a quantification step. Extraction of samples with n-hexane is followed by pre-separation of PCB from PAH with a combined aluminasilica column. PCB are identified and quantified by GCECD, whereas GC-FID is used for PAH determination. The recovery rates of the method used to analyze PCB and PAH in the samples are > 80% with RSD of < 10%. Some of PCB and PAH are determined in the samples analyzed, detection frequencies (number of detection in 5 sample for each sampling point) of these compounds are low. In all points of sampling, the highest concentrations belong to PCB 52 and Naphthalene, (0.875 ngL(-1) with frequency of detection 5) (42.60 ngL(-1) with frequency of detection 2), respectively.Öğe Removal of arsenate [As(V)] and arsenite [As(III)] from water by SWHR and BW-30 reverse osmosis(ELSEVIER SCIENCE BV, 2011) Akın, İlker; Arslan, Gülşin; Tor, Ali; Çengeloğlu, Yunus; Ersöz, MustafaThe removal of arsenate [As(V)] and arsenite [As(III)] from water was investigated by using reverse osmosis (RO) technique with SWHR and BW-30 (FILMTEC) membranes. The effect of pH and concentration of the feed water and operating pressure on the rejection of both arsenic species was examined. The experimental results indicated that rejection for both As(V) and As(III) mostly depended on the membrane type, pH of the feed water and operating pressure. For both membranes. As(V) rejection was maximum at pH above 4.0, while As(III) could be effectively removed from water at pH above 9.1. The rejection for both arsenic species increased with increasing operating pressure. The lowest permeate concentration of As(III) and As(V) was obtained when SWHR membrane was used. Finally, a natural (ground) water sample containing 50 mu g/L of As(V) and 12 mu g/L of As(III), respectively was treated by using RO with SWHR membrane. The obtained permeate concentration of total arsenic was compared with WHO and EU standards and permeate fluxes were evaluated by considering the chemical composition of the groundwater sample. (C) 2011 Elsevier B.V. All rights reserved.Öğe Removal of boron from aqueous solution by using neutralized red mud(ELSEVIER SCIENCE BV, 2007) Çengeloğlu, Yunus; Tor, Ali; Arslan, Gülşin; Ersöz, Mustafa; Gezgin, SaitThe adsorptive removal of boron from aqueous solution by using the neutralized red mud was studied in batch equilibration technique. The effects of pH, adsorbent dosage, initial boron concentration and contact time on the adsorption were investigated. The experiments demonstrated that boron removal was of a little fluctuation in pH range of 2-7 and it takes 20 min to attain equilibrium. The adsorption data was analyzed using the Langmuir and the Freundlich isotherm models and it was found that the Freundlich isotherm model represented the measured sorption data well. (c) 2006 Elsevier B.V. All rights reserved.Öğe Removal of Cr(III) and Cr(VI) Through the Plasma Modified and Unmodified Ion-Exchange Membranes(Elsevier, 2010) Sardohan, Tuğba; Kır, Esengül; Güleç, Ali; Çengeloğlu, YunusThe removal of trivalent and hexavalent chromium ions through charged ion-exchange membranes by using two detachable compartments was studied under Donnan dialysis conditions. The surfaces of ion-exchange membranes were treated by electron cyclotron resonance plasma (ECR) to increase the performance. The effects of plasma modified ion-exchange membranes and pH on removal chromium ions were investigated at 25 degrees C. The flux values (J) and recovery factor (RF) of trivalent and hexavalent chromium ions before and after the plasma modification were obtained. The flux values and recovery factors for plasma modified SA(3)S. SA(3)T and SB-6407 ion-exchange membranes are higher than that of unmodified membrane. This can be explained by change of morphology of pores in the plasma modified membranes. The surface morphology of the plasma modified and unmodified ion-exchange membranes are characterized by SEM and AFM. Ion-exchange capacity, membrane potential measurement and sorption capacity measurements were carried out in order to understand how the plasma treatment affected on the membrane charge selectivity. As a result no change for charge selectivity was observed.Öğe Removal of Fluoride From Aqueous Solution by Using Red Mud(ELSEVIER SCIENCE BV, 2002) Çengeloğlu, Yunus; Kır, Esengül; Ersöz, MustafaThe removal of fluoride from aqueous solution by using the original and activated red mud forms was studied in batch equilibration technique. Influence of pH. adsorbent dose and contact time on the adsorption were investigated. The fluoride adsorption capacity of activated form was found to be higher than that of the original form. The maximum removal of fluoride ion was obtained at pH 5.5. The removal of fluoride was expressed with Langmuir and Freundlich isotherms. Langmuir adsorption isotherm Curve was found to be significant. It was found that the sufficient time for adsorption equilibrium of fluoride ions is 2 h. The possibility of removal of fluoride ion by using red mud is explained on the basis of the chemical nature and specific interaction with metal oxide surfaces and the results are interpreted in terms of PH variations. (C) 2002 Elsevier Science B.V. All rights reserved.Öğe Removal of nitrate from aqueous solution by using red mud(ELSEVIER SCIENCE BV, 2006) Çengeloğlu, Yunus; Tor, Ali; Ersöz, Mustafa; Arslan, GülşinThe objective of this study is to remove the nitrate from aqueous solution by using the original and activated red mud in batch adsorption technique. The effects of pH, adsorbent dosage and contact time on the adsorption were investigated. The nitrate adsorption capacity of activated red mud was found to be higher than that of the original form and decreased above pH 7. Adsorption process was expressed by using Langmuir and Freundlich isotherms. Langmuir isotherm curves was found to be significant compared to Freundlich isotherm. Adsorption capacity of the original and activated red mud was found to be 1.859 and 5.858 mmol nitrate/g red mud, respectively. It was found that sufficient time for adsorption equilibrium of nitrate ions is 60 min. The mechanism for nitrate removal was explained by considering of chemical nature of red mud and interaction between metal oxides surface and nitrate ions. (c) 2006 Elsevier B.V. All rights reserved.Öğe Removal of nitrate from the aqueous phase by Donnan dialysis(ELSEVIER, 2009) Altıntaş, Özlem; Tor, Ali; Çengeloğlu, Yunus; Ersöz, MustafaThe removal of nitrate ions through SB-6407 and Neosepta AMX anion exchange membranes has been studied under Donnan dialysis conditions as I a function of receiver phase concentration and co-existence anions in the feed phase. For both membranes, it was observed that the transport of nitrate increased with increase of the receiver phase concentration and decreased ill the presence of co-existence anions in feed phase. It was also observed that the nitrate transport efficiency of the SB-6407 was higher than that of the Neosepta AMX membrane. The transport of nitrate ions was correlated with the flux data and explained according to the membrane structure.Öğe Removal of phenol from aqueous phase by using neutralized red mud(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2006) Tor, Ali; Çengeloğlu, Yunus; Aydın, Mehmet Emin; Ersöz, MustafaThe objective of this study is to remove the phenol from aqueous solution by using the neutralized red mud in batch adsorption technique. The study was carried out as functions of contact time, pH, initial phenol concentration, red mud dosage and effect of salt addition. The experiments demonstrated that maximum phenol removal was obtained in a wide pH range of 1-9 and it takes 10 h to attain equilibrium. The adsorption data was analyzed using the Langmuir and the Freundlich isotherm models and it was found that the Freundlich isotherm model represented the measured sorption data well. The influence of addition of salt on phenol removal depends on the relative affinity of the anions for the red mud surface and the relative concentrations of the anions. (c) 2006 Elsevier Inc. All rights reserved.Öğe Selectively facilitated transport of Zn(II) through a novel polymer inclusion membrane containing Cyanex 272 as a carrier reagent -- 2(IWA PUBLISHING, 2012) Yılmaz, Abdurrahman; Arslan, Gülşin; Tor, Ali; Akın, İlker; Çengeloğlu, Yunus; Ersöz, Mustafa[Abstract not Available]
