Sürdürülebilir Kalkınma Amaçları
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- MakaleYalnız künye2020Scopus SJRQ1A thermodynamic and kinetic approach to adsorption of methyl orange from aqueous solution using a low cost activated carbon prepared from Vitis vinifera L.
Yönten, Vahap; Sanyürek, Nesrin Karaca; Kivanç, Mehmet Rıza
In this paper, thermodynamic and kinetic parameters of the Methyl Orange adsorption process on active carbon prepared from endemic Vitis vinifera L. grape seeds (AC-VVL) grown in the Tunceli-Elazığ region and % removal of dye from aqueous solutions were evaluated by using a batch system. Experiments were performed as a function of pH (2, 5, 8 and 11), temperature (15 °C, 30 °C and 45 °C) and initial concentration (100, 150, 300 and 1000 mg L−1). The mechanism and characterization of adsorption of dye was analyzed pre-adsorption (AC-VVL) and post-adsorption (AC-VVL+dye) using FTIR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscope) and Brauner Emmet and Teller (BET) analyzer. The activation energy (Ea) was determined as 24.80, 39.15, −22.40 and 61.73 kJ/mol for 100, 150, 300 and 1000 mg L−1, respectively. The Langmuir, Freundlich, Temkin and Harkins Jura isotherms were used to describe the adsorption equilibrium studies at different temperatures. The Freundlich isotherm shows better fit than other isotherms in the temperature range studied. Maximum adsorption occurred at pH 2 and was approximately 79.7 mg/g. The % Recycling Yield was found to be 20% and 9 mg/g with acetone. Thermodynamic parameters like the change in enthalpy (ΔH o), entropy (ΔS o) and Gibbs free energy (ΔG o) were evaluated and the adsorption process was found to be endothermic and spontaneous. The results show that this AC-VVL biomass is an appropriate biosorbent and has specific affinity for removal of Methyl Orange from aqueous solutions.
AtıfScopus109WoS103OpenAlex111
İncele - MakaleYalnız künye2017Ucuz ve Çevre Dostu Bir Adsorbent Olan Üzüm Çekirdeği ile Metilen Mavisinin Sulu Çözeltilerden Gideriminde RSM Kullanımı
Sanyürek, Nesrin Karaca; Yönten, Vahap
Ucuz ve atık olarak değerlendirilen üzüm çekirdeği insanların gıda olarak kullandığı üzümden elde edilen ve bol miktarda bulunan bir atıktır. Bu atık aktif karbon haline getirilerek bir boyar madde olan Metilen Mavisinin (MM) sentetik atık sulardaki gideriminde kullanılmıştır. Optimizasyon süreci Response Surface Metodology (RSM) kullanılarak tamamlanmıştır. Çalışılan süreçte giderimi etkileyecek dört farklı parametre seçilmiş ve bu parametreler optimize edilerek maksimum Metilen mavisi giderimi bulunmuştur. Bu parametrelerin herbirinin (pH, zaman (dakika), adsorbent miktarı (g) ve başlangıç derişimi mgL-1) cevap üzerindeki etkileri Central Compozite Design (CCD) programı kullanılarak hesaplanmıştır. Yapılan deneysel çalışmalar sonucunda quadratik bir model bulunmuş ve üç boyutlu grafikler elde edilerek Anova istatiksel verileri hesaplanmıştır. Gerçekleştirilen deneysel ve istatiksel çalışmalar sonucunda bağımsız parametrelerin maksimum değerleri pH 3.7, süre 55.5 dakika, adsorbent miktarı 1.4 gram ve başlangıç derişimi 160 mgL-1 olarak bulunmuştur. Bu veriler kullanılarak aktif karbon (Vitis vinifera L.) ile sentetik atık sulardan yaklaşık %99 verimle Metilen mavisi giderimi sağlanmıştır. Aynı zamanda bulunan modelin yapılan çalışmayı %82 desteklediği gözlenmiştir.
- MakaleAçık Erişim2017Scopus SJRQ2Exploring thermodynamics and kinetic parameters of immobilized catalase enzyme via adsorption on krill clay
Nas, Mehmet Salih; Gür, Aycan; Gür, Tugba; Yönten, Vahap
The thermodynamic parameters and immobilization kinetics of catalase enzyme via adsorption onto krill clay were performed in aqueous solution in batch system. The adsorbent was characterized by X-ray fluorescence, scanning electron microscope and Brunauer-Emmett-Teller N-2 adsorption measurements. The effect of some parameters to the adsorption process such as contact time, stirring speed, initial enzyme concentration, initial ionic strength, temperature and pH were analyzed. Maximum adsorption capacity (q(m)) showed a great dependence on pH and initial enzyme concentration. It was found at pH 5.5, and initial enzyme concentration, 0.0075 g L-1 values. Pseudo-first-order, pseudo-second-order and intraparticle diffusion were used to fit the kinetics data on kinetic models. Furthermore, thermodynamic activation parameters such as enthalpy, entropy, Gibbs free energy and activation energy (Delta H degrees, Delta S degrees, Delta G degrees and E-a) which reveal that catalase enzyme adsorption occur spontaneously and in endothermic nature were determined. The obtained results confirmed that the applicability of krill clay is an efficient immobilizing supporter for catalase enzyme and krill clay material can be used as a very effective adsorbent in immobilization of this enzyme from aqueous solutions.
AtıfWoS9OpenAlex13İncele - MakaleAçık Erişim2015Scopus SJRQ4Optimization of lipase production on agro-industrial residue medium by Pseudomonas fluorescens (NRLL B-2641) using response surface methodology
Tanyol, Mehtap; Uslu, Gulsad; Yönten, Vahap
The aim of our research was to explore the most cost-efficient and optimal medium composition for the production of lipase from Pseudomonas fluorescens (NRLL B-2641) culture grown on sunflower oil cake (SuOC) by applying response surface methodology (RSM). The oil cake was used instead of carbon sources. Peptone, ammonium sulphate and the carbon source (SuOC) were the most important factors as it is obligatory for microbial growth. Subsequently, the optimum values for the carbon source, peptone and ammonium sulphate were found to be 11.10% (w/v), 1.18% (w/v) and 0.83% (w/v), respectively. Experiments carried out under optimum conditions revealed a maximum lipase activity of 10.8 U mL(-1), which was achieved after 48 h of fermentation. The obtained results were finally verified with batch experiments carried out under the optimum conditions evaluated and it was demonstrated that the SuOC from agro-industrial residue as substrates can be used as an inexpensive base (carbon source) for the production of lipase by P. fluorescens (NRLL B-2641).
AtıfWoS19İncele - MakaleYalnız künye2014Scopus SJRQ3EXPLORING THE OPTIMUM CONDITIONS FOR MAXIMIZING THE MICROBIAL GROWTH OF Candida intermedia BY RESPONSE SURFACE METHODOLOGY
Yönten, Vahap; Aktas, Nahit
Exploring optimum and cost-efficient medium composition for microbial growth of Candida intermedia Y-1981 yeast culture growing on whey was studied by applying a multistep response surface methodology. In the first step, Plackett-Burman (PB) design was utilized to determine the most significant fermentation medium factors on microbial growth. The medium temperature, sodium chloride and lactose concentrations were determined as the most important factors. Subsequently, the optimum combinations of the selected factors were explored by steepest ascent (SA) and central composite design (CCD). The optimum values for lactose and sodium chloride concentrations and medium temperature were found to be 18.4g/L, 0.161g/L, and 32.4 degrees C, respectively. Experiments carried out at the optimum conditions revealed a maximum specific growth rate of 0.090 1/hr; 42% of total lactose removal was achieved in 24h of fermentation time. The obtained results were finally verified with batch reactor experiments carried out under the optimum conditions evaluated.
AtıfWoS14OpenAlex16
İncele - MakaleAçık Erişim2013Scopus SJRQ4Adsorption of the 2,2-Dichlorovinylphosphate on Raw and Modified Bentonites
Yönten, Vahap; Kubilay, Senol
This study aims to investigate the adsorption of the 2,2-dichlorovinylphosphate (DDVP) on raw and modified bentonite via high pressure liquid chromatography and infrared spectroscopy. The modified bentonites were prepared by adding HNO3 and Na2CO3. The Freundlich adsorption isotherm defines 2,2-dichlorovinylphosphate adsorption in aqueous and aqueous ethanol solutions through raw and modified bentonite. Variables such as temperature, time and pH were observed on 2,2-dichlorovinylphosphate adsorption. Then the capacity for maximum 2,2-dichlorovinylphosphate adsorption was measured on modified bentonite with HNO3 under the conditions of pH 3 and 40 degrees C. The modified bentonite with Na2CO3 clay used in experimental work played a major role on the adsorption of 2,2-dichlorovinylphosphate; thus modified bentonite with Na2CO3 is considered to possess better characteristics than modified bentonite with HNO3 and raw bentonite. The Freundlich isotherms of modified bentonite with Na2CO3 in aqueous-ethanol solution were found to be better than isotherms of aqueous solution for a much better 2,2-dichlorovinylphosphate adsorption.
AtıfOpenAlex1İncele - MakaleYalnız künye2013Scopus SJRQ2DETECTING OPTIMUM AND COST-EFFICIENT OF MICROBIAL GROWTH RATE AND LACTOSE CONSUMPTION OF KLUYVEROMYCES LACTIS Y-8279 USING RSM
Yönten, Vahap
Exploring optimum and cost-efficient medium composition for microbial growth rate and lactose consumption of Kluyveromyces Lactis Y-8279 yeast culture growing on whey was studied by applying a multi-step response surface methodology (RSM). RSM is a combination of Plackett Burman (PB), Steepest-Ascent (SA) and Central Composite Design (CCD) Medium temperature, pH, yeast extract and lactose concentrations were evaluated the most effective operational factors through seven factors by applying PBD. These four factors were selected for SA program and SA experiments were carried out to find approximately maximum microbial concentration with lactose, pH, yeast extract and medium temperature. Then CCD was carried out with these factors (lactose, medium temperature, pH and yeast extract). Based on ANOVA test the optimum operational conditions of maximum growth rate were obtained as 18.8 g/L, 0.94 g/L, 5.2 and 27 degrees C, lactose concentration, yeast extract concentration, pH, and medium temperature, respectively. And then optimum operational conditions of lactose consumption were obtained as 13 g/L, 0.91 g/L, 8 and 27.5 degrees C, lactose concentration, yeast extract concentration, pH, and medium temperature, respectively too.
AtıfWoS1İncele
