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154 results on '"Özcan, A. Safa"'

27. Biosorption performance of thiosalicylic acid modified isatis tinctoria for Pb(II) and Cd(II) ions: batch and column studies.

Author

Alp Arici, Tuğba, Özcan, A. Safa, and Özcan, Adnan

Subjects
*METAL ions, *IONS, *LANGMUIR isotherms, *AQUEOUS solutions, *BIOELECTROCHEMISTRY, *SORPTION, *METAL complexes
Abstract

The biosorption of Pb(II) and Cd(II) ions onto thiosalicylic acid modified Isatis tinctoria (TS-I) was investigated. The characterization of I. tinctoria and TS-I were determined by SEM, FT-IR and TGA. The biosorption equilibrium and kinetic data well matched with the Langmuir isotherm and pseudo-second-order kinetic models, respectively. The biosorption of metal ions from the synthetic wastewaters was also investigated in the systems. TS-I has a very high biosorption capacity for metal ions due to the chelating effects of thiosalicylic acid in metal complexes and, it is an effective and eco-friendly biosorbent for the biosorption of metal ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

Published
2021
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30. Effects of different parameters on the synthesis of silica aerogel microspheres in supercritical CO2 and their potential use as an adsorbent.

Author

Başaran, Ersin, Alp Arıcı, Tuğba, Özcan, Adnan, Gök, Özer, and Özcan, A. Safa

Abstract

Synthesis of metal oxide microspheres in supercritical carbon dioxide (SCO2) is very attractive for a wide range of applications such as catalysis, controlled release, and separation science due to their identical properties. The aim of this study is the synthesis of silica microspheres (SM) in SCO2 by sol-gel method. The effects of temperature, pressure, flow rate, time, co-solvent and its ratio on the synthesis of silica microspheres in SCO2 were investigated. The synthesized microspheres were characterized by several techniques including field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), and surface area analysis. The results indicated that the optimum condition for the synthesis of SM was determined at 150 bar, 80 °C, and 2.5 mL min−1 of SCO2 flow rate. The usability of SM as an adsorbent for the removal of dyes and heavy metals from aqueous solutions was also examined. Kinetic and isotherm studies for the adsorption of Pb(II) ions and Acid Blue 260 (AB260) onto SM were carried out. [ABSTRACT FROM AUTHOR]

Published
2019
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31. Preparation of HDTMA-bentonite: Characterization studies and its adsorption behavior toward dibenzofuran

Author

Erdem, Bilge, Özcan, Asiye Safa, Özcan, Adnan, Anadolu Üniversitesi, Fen Fakültesi, Fizik Bölümü, Özcan, Asiye Safa, and Özcan, Adnan

Subjects
Kinetics, Thermodynamics, Adsorption, Dibenzofuran, Organoclay, Surface Characterization
Abstract

13th European Conference on Applications of Surface and Interface Analysis -- OCT 18-23, 2009 -- Antalya, TURKEY, WOS: 000281149700197, Bentonite is one of the most commonly used raw materials in the water treatment processes because of its low cost, easily availability and high mechanical and chemical stability. In this study, natural bentonite was modified with a large organic surfactant, which is hexadecyltrimethyl ammonium (HDTMA) bromide. The modified bentonite was called organobentonite. The surface characterization of natural bentonite and HDTMA-bentonite was examined by Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry(XRD), Brunauer-Emmett-Teller (BET) and thermogravimetric(TG) analysis. FTIRspectroscopy showed the existence of HDTMA functional groups on bentonite surface. XRD results revealed randomly lateral-monolayer arrangements of the intercalated alkylammonium cation. The BET surface area significantly decreased after the modification due to the coverage of the pores of natural bentonite. Differences in the differential thermogravimetric (DTG) peaks for natural-and HDTMA-bentonite were observed and interpreted. HDTMA-bentonite was then tested as an adsorbent for the removal of organic compounds such as dibenzofuran (DBF) from aqueous solutions. The amount of adsorption for HDTMA-bentonite was found to be around 20 times higher than that of natural bentonite in 10 mg dm(-3) DBF solution at 20 degrees C. The adsorption kinetics of DBF onto HDTMA-bentonite was also studied at 20, 30 and 40 degrees C and thermodynamic parameters were calculated. The overall adsorption process was exothermic and physical in nature. The results indicate that HDTMA-bentonite is an effective and a low-cost adsorbent for the removal of heterocyclic aromatic compounds such as DBF. Copyright (C) 2010 John Wiley & Sons, Ltd.

Published
2010

32. Modification of bentonite with a cationic surfactant: An adsorption study of textile dye Reactive Blue 19

Author

Özcan, Adnan, Ömeroğlu, Çiğdem, Erdoğan, Yunus, Özcan, A. Safa, Anadolu Üniversitesi, Fen Fakültesi, Fizik Bölümü, Özcan, Adnan, and Özcan, Asiye Safa

Subjects
Environmental Engineering, Health, Toxicology and Mutagenesis, Anthraquinones, Isotherms, symbols.namesake, Surface-Active Agents, Adsorption, Pulmonary surfactant, Environmental Chemistry, Coloring Agents, Waste Management and Disposal, Aqueous solution, Chromatography, Reactive Dye, Chemistry, Cationic polymerization, Langmuir adsorption model, Pollution, Gibbs free energy, Chemical engineering, Textile Industry, Bentonite, symbols, Surface modification, Thermodynamics, Organoclay
Abstract

WOS: 000244362500019, PubMed ID: 16920256, The utilization of modified bentonite with a cationic surfactant (dodecyltrimethylammonium (DTMA) bromide) as an adsorbent was successfully carried out to remove a synthetic textile dye (Reactive Blue 19 (RB 19)) by adsorption, from aqueous solutions. Batch studies were carried out to address various experimental parameters such as pH, contact time and temperature. The surface modification of bentonite with a surfactant was examined using the FTIR spectroscopic technique and elemental analysis. Effective pH for the adsorption of RB19 onto DTMA-bentonite was around 1.5. The Langmuir isotherm model was found to be the best to represent the equilibrium with experimental data. The maximum adsorption capacity (q(max)) has been found to be 3.30 x 10(-4) mol g(-1) or 206.58 mg g(-1). The thermodynamic study indicated that the adsorption of RB19 onto DTMA-bentonite was favored with the negative Gibbs free energy values. The pseudo-second-order rate equation was able to provide the best description of adsorption kinetics and the intraparticle diffusion model was also applicable up to 40 min for the adsorption of RB 19 onto DTMA-bentonite

Published
2006

35. Doğal Bentonitin Karakterizasyonu ve Kurşun(II) İyonlarını Adsorpsiyon Yeteneği

Author

Özcan, Asiye Safa

Subjects
Bentonite,characterization,adsorption,heavy metal,lead(II) ions, Bentonit,karakterizasyon,adsorpsiyon,ağır metal,kurşun(II) iyonları
Abstract

Natural bentonite is one of the most commonly used adsorbent in the removal of heavymetals because of its low cost, easily availability and high mechanical and chemicalstability. In the present study, natural bentonite was firstly characterized by usingBrunauer-Emmett-Teller (BET), X-ray diffractometry (XRD), Fourier transforminfrared (FTIR) spectroscopy and thermogravimetric (TG) analysis methods. Secondly,natural bentonite was used as an adsorbent for the determination of the adsorptionability of lead(II) ions from aqueous solution at various pHs, temperatures andconcentrations. The obtained results indicate that natural bentonite is an effectiveadsorbent for the removal of heavy metals from aqueous solutions., Doğal bentonit, yüksek kimyasal ve mekanik kararlılığından, kolaylıklabulunabilmesinden ve fiyatının ucuz olmasından dolayı ağır metallerin giderilmesindeen çok kullanılan adsorbanlardan biridir. Bu çalışmada, doğal bentonit öncelikleBrunauer-Emmett-Teller (BET), X-ışınları kırınımı (XRD), Fourier transform infrared(FT-IR) spektroskopisi ve termogravimetrik (TG) analiz yöntemleri ile karakterizeedilmiştir. Daha sonra doğal bentonit, farklı pH, sıcaklık ve derişimlerde suluçözeltiden kurşun(II) iyonlarını adsorplama yeteneğinin belirlenmesi için adsorbanolarak kullanılmıştır. Elde edilen sonuçlar doğal bentonitin sulu çözeltiden ağırmetallerin giderimi için etkili bir adsorban olduğunu göstermiştir.

Published
2010

36. Süperkritik karbon dioksitte boyama

Author

Devrent, Nalan, Özcan, A. Safa, Durur, Güngör, and Anadolu Üniversitesi, Fen Fakültesi, Kimya Bölümü

Subjects
Siiperkritik boyama,pamuk,dispers boyannaddeler,modifikasyon, Supercritical dyeing,cotton,disperse dyestuffs,modification, Engineering, Mühendislik, Ortak Disiplinler
Abstract

Tekstil materyallerinin klasikyontemlere gore boyanmasmda su kuIlal1lml ve bunun sonucunda olu~an atlksu, ,eYre aylsmdan onemli bir sorundur., Water consumption and exhaustion in dyeing textile materials in conventional methods IS an important environmental problem. Increasing consideration of ecologic consequences of industrial processes as well as legislation enforcing the avoidance of environmental problems have caused a reorientation of thinking and promoted projects for replacement of conventional technologies. One of these new technologies is dyeing in supercritical fluids. During this dyeing process no water is used, therefore there is no waste water problem. The necessary energy consumption in this process is relatively lower than is needed to heat water in conventional methods of dyeing. Due to unnecessary of drying process, it helps to save both energy and time.

Published
2006

37. Evaluation on dye removal capability of didodecyldimethylammonium-bentonite from aqueous solutions.

Author

Öncü-Kaya, Elif Mine, Şide, Nilgün, Gök, Özer, Özcan, Asiye Safa, and Özcan, Adnan

Subjects
BENTONITE, AQUEOUS solutions, COLOR removal (Sewage purification), X-ray diffractometers, X-ray fluorescence
Abstract

The removal efficiency of Reactive Blue 19 (RB19) by using surfactant-modified bentonite (MB) from aqueous solutions, and also textile wastewater samples was examined. Natural bentonite (NB) was firstly modified with didodecyldimethylammonium bromide (DDDAB) in order to increase the removal capacity of bentonite. MB was then characterized by Fourier Transformed Infrared Spectrophotometer (FTIR), x-ray diffractometry (XRD), x-ray fluorescence (XRF), Scanning Electron Microscope (SEM)/EDX, zeta potential, elemental, and thermal analysis techniques. The high adsorption capacity of MB was 407.7 mg g−1at pH = 1.5 and 20°C. The adsorption of Reactive Blue 19 onto MB agreed with the pseudo-second-order kinetic and Langmuir isotherm models. [ABSTRACT FROM AUTHOR]

Published
2017
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38. Characterization and lead(II) ions removal of modified Punica granatum L. peels.

Author

Ay, Çiğdem, Özcan, Asiye Safa, Erdoğan, Yunus, and Özcan, Adnan

Subjects
*METAL ions, *POMEGRANATE, *SORPTION, *HEXAMETHYLENEDIAMINE, *AQUEOUS solutions, *ZETA potential, *LANGMUIR isotherms
Abstract

The aim of the present study was to enhance the biosorption capacity of a waste biomass ofPunica granatumL. peels (PGL) using various chemical modification agents. Among these agents, hexamethylenediamine (HMDA) indicated the best performance with regard to the improvement of lead(II) ions removal from aqueous solution. The characterization of HMDA-modifiedP. granatumL. peels (HMDA-PGL) was achieved by using elemental analysis, FT-IR, thermogravimetric (TG) analysis and zeta potential measurement techniques. Based on FT-IR study, the chemical modification of P. granatum L. peels take place with its carboxyl, carbonyl, hydroxyl, etc. groups and these groups are responsible for the biosorption of lead(II) ions onto modified biomass. Biosorption equilibrium and kinetic data fitted well the Langmuir isotherm and the pseudo-second-order kinetic models, respectively. The highest biosorption capacity obtained from Langmuir isotherm model was 371.36 mg g−1. Biosorption process was spontaneous and endothermic in nature according to the thermodynamic results and it quickly reached the equilibrium within 60 minutes. The validity of kinetic models used in this study can be quantitatively tested by using a normalized standard deviation Δq(%). [ABSTRACT FROM AUTHOR]

Published
2017
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