Browsing by Author "Koyuncu, Menderes"

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Adsorption of Cr(Vi) From Textile Waste Water by Using Natural Bentonite
(inst integrative Omics & Applied Biotechnology, 2012) Koyuncu, Menderes
Cr(VI) chromium was removed from the artifical wastewater using natural bentonite in batch. The adsorption of the chromium on bentonite was investigated during a series of batch adsorption experiments carried out to determine the effect of three different temperatures and contact time. The amounts adsorbed at equilibrium were measured. The experimental results have been fitted both Langmuir and Freudlich isotherms. The maximum adsorption capacities of the bentonite were found to be 12.65, 10.99 and 9.50 mg/g bentonite at 25, 30 and 35 degrees C, respectively. Several thermodynamic parameters such as. Ho,. Go and. So have been calculated. The results of thermodynamic parameters indicates, spontaneous and an exothermic process. The results showed that bentonite could be used as effective adsorbent for the removal of Cr(VI). In addition, the color changes in the artificial wastewater were measured using colorimetric method. The color difference CIE L *a *b* values between before and after adsorption were determined.
Adsorption of Maxilon Blue Grl From an Aqueous Solution: Equilibrium and Kinetic Studies
(Asian Journal of Chemistry, 2009) Koyuncu, Menderes
Removal of a basic dye, maxilon blue GRL by bentonite, from an aqueous solution was studied. The adsorption of the dye on to bentonite was investigated during batch adsorption experiments carried out to determine the effect of initial, dye concentration and contact time. The Langmuir and Freundlich isotherm models were tested for their applicability. Kinetic studies were conducted in two different temperatures and five different reaction periods. Adsorption stability studies were done with five different dye solutions at 37 degrees C, pH 4.5-5.0 and in 10 h stability periods and adsorption capacities, adsorption stability constants and Langmuir and Freundlich constants were calculated. The experimental data were analysed using the pseudo-first-order adsorption kinetic model. According to this model, the rate constants were evaluated for two different temperatures. The experimental data fit the first-order kinetic model.
Adsorption Properties of Basic Dyes (Maxilon Red Grl and Maxilon Yellow Grl) Onto Bentonite
(Asian Journal of Chemistry, 2009) Koyuncu, Menderes
In this study, adsorption kinetics, thermodynamics and adsorption stability parameters of maxilon red GRL and maxilon yelow GRL which are used in textile industry especially in dyeing of acrylic fibers on to bentonite were studied. The adsorption of the dyes onto bentonite was investigated during a series of batch adsorption experiments to determine the effect of initial dye concentration and contact time. The Langmuir and Freundlich isotherm models were tested for their applicability. Adsorption capacities, adsorption stability constants and Langmuir and Freundlich constants were calculated. Kinetic studies have been made at two different temperatures Adsorption equilibrium studies have been studied using 5 different dye solutions at 37 degrees C, pH 4.5-5.0 and in 10 h. The experimental data were analyzed using the pseudo first-order adsorption kinetic model. According to this model, the rate constants were evaluated at two different temperatures.
Adsorption, Kinetics, and Thermodynamic Study of Dyeing the Scutellaria Orientalis L as an Eco-Friendly Natural Colourant on Cotton Fabric
(inst Natl Cercetare-dezvoltare Textile Pielarie-bucuresti, 2024) Koyuncu, Menderes
The adsorption isotherm, thermodynamic parameter, and kinetics study for dyeing without mordanting cotton fabric dyed with natural dye obtained from an aqueous extract of the Scutellaria Orientalis were investigated using, as optimal conditions, at pH of 5 a material to liquor ratio (MLR) of 1:100, an initial dye concentration of 1.0/l and contact time (20-90 min.). The effect of the temperature and dyeing time (from 20-90 min.) on dyeing was evaluated using three different temperatures (from 60, 80, and 90 degrees C). Also, the adsorption isotherms have been analyzed by Langmuir and Freundlich models. It is revealed that the adsorption kinetics was found to follow the pseudo-first-order kinetic model, the obtained adsorption isotherm was found to be suitable for both Langmuir and Freunlich adsorption isotherm, and the dyeing process is exothermic. The rate of dye uptake and thermodynamic parameters have also been calculated and discussed.
Çevre Dostu Tekstil Üretimi için Yeni Bir Boyama Yöntemi Olarak Üçlü Boya Kombinasyonu ile Boyanmış Yün İpliklerinin Renk ve Haslık Özelliklerinin Araştırılması
(2022) Koyuncu, Menderes
Son zamanlarda artan çevre sorunları nedeniyle tekstil boyama ve baskıda doğal renklendiricilerin kullanımı tekstil ürünleri imalatında ön plana çıkmıştır. Bu çalışmada, yün iplikleri üçlü boya (Scutellaria Orientalis L, Rubia Tinctorium L, and, Punica Granatum L) kombinasyonları ile boyama işlemi yapılmıştır. Boyanmış ipliklerin, yıkama ve ışık haslıkları yapılarak orta - iyi ve iyi değerlerde olduğu görülmüştür. CIELAB (L*, a*, and b*) renk koordinatları, and K/S, ve ∆E* değerleri incelenmiştir. Ayrıca FTIR ve SEM analizleri yapılarak boyamadan sonra değişimler incelenmiştir. Sonuçlardan, üçlü boya kombinasyonlu bitkilerden ekstrakte edilen doğal boyanın, yün iplikleri için iyi bir potansiyele sahip olduğu ve daha fazla yararlanılabileceği söylenebilir.
Colour Removal From Aqueous Solution of Tar-Chromium Green 3g Dye Using Natural Diatomite
(oficyna Wydawnicza Politechniki Wroclawskiej, 2012) Koyuncu, Menderes
Removal of Tar-Chromium Green 3G dye from aqueous solution at different dye concentrations, different temperatures and adsorbent doses has been studied. It was seen that the maximum of 88% adsorption has been achieved from the wastewater using 3.0 g material at 30 degrees C temperature for shaking time of 60 min. The adsortion isotherms are described by means of the Langmuir and Freudlich isotherms at different temperatures of 25, 30 and 35 degrees C, and the results were discussed. The equilibrium data satisfied both the Langmuir and Freundlich models. Moreover, thermodynamic parameters such as Delta H, Delta S and Delta G were also studied. It was found that the values of standard free energy (Delta G) and the values of standard enthalpy (Delta H) were negative and entropy (Delta S) was found to be positive. Thermodynamic studies showed that the reaction for uptake by diatomite is exohtermic in nature. The results of this study showed that diatomite could be employed as effective and low-cost materials for the removal of the dye from aqueous solution.
A Comparative Study on Conventional Natural Dyeing and Machine Dyeing Methods
(Stef92 Technology Ltd, 2012) Koyuncu, Menderes; Altin, Abdullah
Wool yarn has been dyed with natural colourant extracted from the different natural dyes in the absence and presence of Potassium aluminium sulphate, Copper sulphate and Acetic acid mordants for producing shades of different colours, and then tested for CIE Lab properties. L* value of the washed wool yarn was much higher than not washed wool yarn. Colouration of both the dyeing methods is found to be most effectively accomplished at treatment time. Dyeing on effect of treatment temperature, time and different mordants with Conventional and Machine dyeing methods have been discussed.
Effect of Alkaline Treatment on Mechanical Properties of Voile Fabric Reinforced Epoxy Composites
(Natl inst Science Communication-niscair, 2017) Koyuncu, Menderes
Effect of alkali treatment on the mechanical properties of epoxy composites reinforced with alkali-treated voile fabric has been studied. The voile fabric is treated with different concentrations of NaOH solution (1% and 3%) for 1 h at 20 +/- 2 degrees C. The epoxy-based composite obtained by reinforcing the alkali-treated fabric is evaluated for its tensile strength, and dynamic mechanical properties. Composite reinforced with 3% NaOH solution treated fabric shows significant improvement in tensile strength (similar to 32.72%). This implies that the concentration of NaOH treatment greatly influences the interfacial adhesion between the voile fabric and the epoxy. Results of dynamic mechanical analysis show an increase in the storage moduli of the composites reinforced with 1% and 3% NaOH treated fabric as compared to untreated composites at 20 - 100 degrees C. However, for all the composites, the storage modulus decreases with the increase in temperature with a significant fall in the temperature range 25 - 100 degrees C, indicating that the incorporation of voile fabric in epoxy matrix unconcluded reinforcing effects appreciably at higher temperatures. The loss moduli of untreated and treated composites decrease with the increase in temperature. The glass transition temperatures of the untreated and treated (1% and 3% NaOH) composites are found to be 35.36 degrees C, 35.81 degrees C, and 30.55 degrees C respectively. For all the composites, the value of tan delta decreases with the increase in temperature which indicates the level of interactions between the polymer matrix and the reinforced fabric. The fractured surface of composites is observed using SEM, which indicates the surface modification of the voile fabrics with alkali treatment and subsequent improvement in fibre-matrix adhesion.
Effect of Pumice Powder on Mechanical, Thermal, and Water Absorption Properties of Fiberboard Composites
(Lukasiewicz Research Network - Lodz institute of Technology, 2023) Koyuncu, Menderes; Ulay, Goksel; Seker, Ulvi
Composites were produced using medium-density fiberboard (MDF) flour with pumice powder which was mixed at various ratios by the hand lay-up technique. Mechanical properties, such as tensile and three-point bending strengths, were determined by ASTM D3039 and ASTM D790 respectively. The best three-point bending and tensile strength properties were maximum values obtained from composites containing 20wt% pumice powder (pp) and 50wt% pumice powder (pp) respectively. It is observed that the water absorption rate into the composites decreases with an increase in the pumice powder-to-ratio. The composite filled with 50wt%pumice powder absorbed the least amount of water compared to the other composites. All composites were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and differential scanning calorimetry analysis (DSC). SEM images revealed a near-homogeneous surface partly free of defects and holes. However, lateral profile images showed the presence of MDF flour particles agglomerated and a considerable number of bubbles and cavities that could interfere with the mechanical properties of the composites. The results of the mechanical, and thermal properties suggested that pumice powder epoxy composites with MDF flour can increase their tensile, three-point-bending strength, and glass transition temperature for the pure MDF flour composite.
Experimental Investigation of Epoxy Matrix and Pine Sawdust Reinforced Wood-Polymer Composite Materials
(North Carolina State Univ dept Wood & Paper Sci, 2022) Koyuncu, Menderes
Mechanical, thermal, and water absorption properties of the composites have been studied as a function of sawdust content, using different weight percentage. The characteristics properties of the composites were studied using differential scanning calorimetry and Fourier-transform infrared spectroscopy. Field emission scanning electron microscopy was used to understand the interfacial bonding. The obtained results showed that the 15 wt% composites exhibited the highest tensile strength (7.5 MPa) and flexural strength (8.9 MPa) compared with the 5 wt%, 30 wt%, 40 wt%, and 50 wt% composites. A good interfacial combination was formed between 15 wt% of sawdust and epoxy resin. In terms of the tensile and flexural strength, the differential scanning calorimetry analysis confirmed that matrix modification could improve the mechanical properties and thermal stability of the composites compared to neat resin. The Fourier-transform infrared spectroscopy spectrum showed the presence of functional groups pertaining to composites. The absorption data of the composite showed that the water uptake increased as the amount of sawdust in the composite increased. The 5 wt%, 15 wt%, 30 wt%, and 40 wt% sawdust composites also displayed less water absorption behavior (1.534%, 1.871%, 2.492%, and 4.127%, respectively) compared to the 50 wt% composite.
Flammability Behavior of Hemp Fibre Reinforced Epoxy Composites
(Polish Mineral Eng Soc, 2024) Koyuncu, Menderes
In this study, the behavior of hemp fiber/epoxy composites subjected to flammability properties. for the production of composite samples, hemp reinforcements were used: unidirectional two balanced laminates (00/900) different in thickness were studied: 2 plies, 4 plies. The composites were fabricated by hand lay-up process the flammability properties of composites are analyzed by using UL-94. The effects of two different fire retardant compounds (Magnesium hydroxide and Aluminum hydroxide) filling on the Underwriters Laboratories (UL)-94 horizontal and vertical tests were carried out for evaluating the effectiveness of these FR treatments. The effects of 2- 4% Mg (OH)2 and Al (OH)3 loading on the composites' burning rate was studied. It was seen that the composite results of vertical burning tests classified these composites under No Classification. The rate of burning of the composites decreased with the inclusion of fire retardants and the rate of burning of 11,60 and 11,22 and 12,20, and 10,60 mm/min was found with 4% wt of Mg(OH)2 and Al(OH)3 in composites respectively.
Investigation of Colorimetric Properties of Woolen Yarn Dyed With Rheum Ribes Plant Root Extract
(Asian Journal of Chemistry, 2007) Koyuncu, Menderes
The dyeing of wool yarn using Rheum ribes roots as natural dye has been studied in conventional method. The effects of dyeing show higher colour strength values obtained by the latter. Dyeing with Rheum ribes roots has been shown to give good dyeing results. The results of washing fastness properties of the dyed wool yarn were fait to good. CIELAB values have also been evaluated and discussed.
An Kinetic Study for Wool Fabrics Chromium Dyeing Using the Pek Model
(inst Natl Cercetare-dezvoltare Textile Pielarie-bucuresti, 2015) Koyuncu, Menderes
Chromium dyeing kinetic on wool fabrics using the PEK model has been studied. The adsorption of the dye on to wool fabric was analysed by fitting the experimental data by means of the PEK model The dyeing experiments are carried out using liquor-to materials ratio of 25:1 in a sealed stainless steel dyebath housed. PEK model is proposed that describes the dye exhaustion at different time. Recently, the mathematical equation of the PEK model is used to interpret the experimental data in terms of kinetic parameters of the dye molecules. With the PEK model, the adsorption kinetics is composed of two exponential terms which represent fast and slow processes, with their own characteristic times and solution of dye contents. The results show that the theoretical estimates are in reasonable agreement with experimental data with higher average regression coefficients.
Mahonia Aquifolium Nutt. (Berberidaceae, Mahonya) Meyvesi ile Boyanmış Yün İpliklerinin Kolorimetrik Özellikleri
(2008) Koyuncu, Menderes
Mahonia aquifolium Nutt. (Berberidaceae) Mahonya bitki meyvesi ile yün iplikleri, hem geleneksel hem de teknik yöntem olmak üzere iki şekilde mordanlı ve mordansız boyama işlemi yapılmıştır. Her iki boyama yönteminde sabit pH'da sıcaklık ve boyama süresinin boyama işlemine etkinliği araştırılmıştır. Geleneksel ve bilimsel boyama yöntemi ile elde edilen renkler ve bu renklerin yıkama haslık özellikleri belirlenmiş ve renkli ipliklerin yıkamaya karşı haslıklarının iyi olduğu görülmüştür. Ayrıca, objektif bir değerlendirme yapabilmek için CIE L*a*b* renk uzay sistemi kullanılarak boyalı ipliklerin L*a*b*değerleri ölçülerek, karşılaştırılmıştır
Removal of Maxilon Red Grl From Aqueous Solutions by Adsorption Onto Silica
(Oriental Scientific Publ Co, 2009) Koyuncu, Menderes
The adsorption of basic dyes (maxilon red GRL) from an aqueous solutions by silica was investigated. Adsorption of maxilon red (GRL) onto silica samples was studied by batch adsorption techniques at 24 +/- 1 degrees C. The adsorption behavior of maxilon red (GRL) on silica samples was investigated using a Uv-vis spectrophotometric technique. In batch system, the effect of five different initial dye concentrations and using six different times on adsorption was evaluated. Values of the removal efficiency of the dye ranged from 47.7 to 96%. The equilibrium adsorption isotherms have been studied by Langmuir and Freundlich models. The experimental results have been fitted Langmuir and Freundlich models. Langmuir adsorption capacity, q(m), was found to be 3.03 mg/g silica at 24 +/- 1 degrees C. Also, initial concentrations and the equilibrium concentration of dye solutions were subjected to a comprehensive colorimetric appraisal using the CIE L*a*b* colour space system.
Static and Dynamic Mechanical Properties of Cotton/Epoxy Green Composites
(inst Chemical Fibres, 2016) Koyuncu, Menderes; Karahan, Mehmet; Karahan, Nevin; Shaker, Khubab; Nawab, Yasir
A study on the effect of alkaline treatment on the mechanical properties of cotton fabric reinforced epoxy composites is presented in this paper. One hour treatment of cotton fabric was performed using three different concentrations of sodium hydroxide (NaOH) solution. 1% NaOH treated fabric reinforced composites exhibited maximum improvement in tensile strength. It was concluded that the said NaOH concentration improves interfacial adhesion between the cotton fabric and epoxy resin. Moreover the morphology of the fracture surface, evaluated by scanning electron microscopy (SEM), indicated that surface treatment can yield better adhesion between the fabric and matrix, demonstrating the effectiveness of the treatment. The dynamic mechanical analysis (DMA) results revealed that alkali treated (1% and 3% NaOH) fabric composites exhibit higher storage moduli and glass transition temperature (Tg) values as compared to the untreated fabric composites. However, for all the composite specimens, the storage modulus decreased with increasing temperature (25 -100 degrees C). Tg values of 50.9, 56.7, 52.8 and 37.7 degrees C were recorded for the untreated and (1%, 3% and 5%) treated composites, respectively. The tan delta values decreased for all the composites with increasing temperature, indicating enhanced interactions between the polymer matrix and fabric reinforcement.
Thermodynamics and Adsorption Studies of Dye (rhodamine-B) Onto Natural Diatomite
(oficyna Wydawnicza Politechniki Wroclawskiej, 2014) Koyuncu, Menderes; Kul, Ali Riza
Thermodynamics and adsorption studies were conducted with a dye of rhodamine-B on natural diatomite. Adsorption of the dye was investigated with an initial dye concentration at pH 8 +/- 0.2, 303, 313 and 323 K. The adsorption experiments were carried out isothermally at three different temperatures. The Langmuir and Freundlich isotherm models were used to describe the equilibrium data and the results were discussed in details. The kinetic data agreed with the pseudo-first order model with rate constants (k(2)) in the range of 3.05-1.59.10(-1) g/mg min. The thermodynamic parameters such as standard free energy, entropy change and enthalpy were calculated for natural diatomite. These values showed that adsorption of rhodamine-B on natural diatomite was a spontaneous and endothermic process.