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Abstract Adsorption properties of Cr(III) and Cr(VI) on natural (NCS), acid-activated (ACS) and base-activated (BCS) cherry stalks (CS) in Isparta were investigated in aqueous solutions. Batch adsorption studies had been completed with different initial chromium concentrations, pH, temperature, time and biosorbent dosage. Adsorption rapidly approached an equilibrium state between 10 and 60 min. The results displayed that the adsorption system was suitable for pseudo-second-order kinetics. Equilibrium isotherms (Langmuir, Freundlich and Dubinin–Radushkevich) were measured experimentally. The retention characteristics of Cr(III) onto NCS, ACS and BCS and Cr(VI) onto ACS were represented by Langmuir adsorption isotherms, while Cr(VI) ions onto NCS and BCS were compatible with Freundlich adsorption isotherms. The adsorption process was endothermic accompanied by a decrease in entropy and Gibbs energy. An artificial neural network (ANN) model was improved to estimate the efficiency of Cr(III) and Cr(VI) ion’s adsorption. The ANN model can predict the behaviour of the Cr(III) and Cr(VI) ion's adsorption under different circumstances. The results have shown that NCS, ACS and BCS biosorbents open up new possibilities and potential commercial uses in the cherry stalks.

The removal of hazardous dyes from water by magnetic biosorbents has received a lot of interest in recent studies. This is because they are inexpensive and simple to separate from the solution phase. In this study, nano-magnetic Tamarindus indica fruit seed biochar was combined with iron to create a green nano-magnetic/ biochar (BC) composite (nM-BC). Compared to unmodified biochar, modified biochar composite significantly improved the ability to adsorb methyl blue (MB) and malachite green (MG). The Dubinin-Radushkevich, Scathard, Freundlich, Langmuir, and Temkin models were used to analyze the adsorption equilibrium data, and the Langmuir isotherm (R2 =0.952–0.995) provided a good match to the results. Saturated BC adsorption capacities for MB and MG were 3.055 mg/g and 5.577 mg/g, respectively, while nM-BC values for MB and MG were 3.326 mg/g and 20.408 mg/g, respectively. The adsorption process is accurately described by the pseudo-second-order kinetic model. BC and nM-BC both passed four reusability tests. Utilizing FT-IR and SEM instruments BC and nM-BC were characterized. The study demonstrates that biochar can be enhanced with nano-iron which has a potent ability to remove dyes utilizing a green manufacturing approach.

Son yıllarda katı partiküller ve sıvıların kaplanması için çeşitli metotlar yayınlanmaktadır. Mikrokapsülleme işlemi de bu metotlar arasında yer almaktadır. Mikrokapsülleme, sıvı ya da katı partikül ya da damlacıklarının polimer bir film malzemesi ile kaplanması işlemidir. Mikroenkapsülasyon teknolojisi yaygın olarak ilaç, gıda, tarım pestisit, kozmetik, tekstil ve diğer ilgili alanlarda uygulanmaktadır. Bu çalışmada, α- tokoferol (E vitamini) içerikli mikrokapsüller, jelatin ve arap zamkı polimer karışımları kullanılarak kompleks koaservasyon yöntemi ile oluşturulmuştur. Emülsiyonu oluşturmak için yüzey aktif madde ve mikrokapsül duvarına çözünmezlik özelliği kazandırmak için çapraz bağlayıcı kullanılmıştır. Polimer oranı, yüzey aktif maddenin miktarı, çapraz bağlayıcı miktarı gibi parametrelerin mikrokapsülasyona etkileri incelenmiştir. Mikrokapsüllerin morfolojisi taramalı elektron mikroskobu (SEM) ile karakterize edilmiştir. Mikrokapsülasyonu açıklamak ve kimyasal yapısını araştırmak için Fourier dönüşümü kızılötesi spektroskopi (FT-IR), termogravimetrik analiz (TGA), yüksek performanslı sıvı kromatografi (HPLC) gibi analizler yapılmıştır.

Özet: Yapılan çalışmada, doğal bir polimer olan kitosan polimeri ile polivinil alkol (PVA) polimeri kullanılarak elektrostatik lif çekim (elektrospinning) yöntemi ile nananolif eldesi gerçekleştirilmiştir. Çapraz bağlayıcı olarak çözeltiye gluteraldehit (GA) ilave edilmiştir. Çekilen nanoliflerin arasına nanokil konularak PVA/Kitosan nanolif-nanokil yüzey elde edilmiştir. Elde edilen nanokil katkılı PVA/Kitosan nanolif yüzeyin taramalı elektron mikroskobu (SEM) görüntüleri alınarak lif morfolojisi ve lif boyutları incelenmiş ve lif çaplarının 110-140 nm arasında oluştuğu görülmüştür. FT-IR analizleri ile elde edilen yüzeyin yapısındaki fonksiyonel gruplar incelenmiş, çapraz bağların oluştuğu gözlenmiştir. TGA (termal gravimetrik analiz) yöntemi kullanılarak sıcaklık değişimi ile numunedeki ağırlık kaybı incelenmiş ve iki aşamalı bozunmanın gerçekleştiği görülmüştür. Anahtar kelimeler: Nanolif, PVA, kitosan, elektrostatik lif çekim, nanokil Synthesis and Characterization of PVA/Chitosan Nanofiber Added Nanoclay Abstract: In this study, nanofibers have been prepared through the electrospinning method in which chitosan- a natural polymer- and polyvinyl alcohol (PVA) polymers were used. Gluteraldehide (GA) was added into the solution as cross-linker. A certain amount of nanoclay was added between the layers of the electrospun nanofibers to obtain PVA/Chitosan nanofiber and nanoclay layer. After that, the fiber morphology and fiber dimensions of the PVA/Chitosan nanofiber and nanoclay were examined by scanning electron microscope (SEM). As a result, it was determined that the diameter of the fiber was between 110 and 140 nm. By FT-IR analysis, the functional groups in the structure of the nanofiber-nanoclay layer and whether the cross-linkers formed were examined. Finally, the change of temperature and the weight loss in the sample were examined through TGA (thermal gravimetric analysis) and it was observed that two-stage degradation occurred. Key words : Nanofiber, PVA, chitosan, electrospinning, nanoclay

Özet: Bu çalışmada, nanolif elde etme yöntemlerinden en yaygın yöntem olan elektrolif çekim (electrospinning) yöntemi kullanılarak, poliakrilonitril (PAN) polimeri ile nanolif üretilmiştir. Üretilen nanolifler arasına daha sonraki çalışmalarda adsorpsiyon amaçlı kullanılabileceği düşünülerek nanokil serpilerek nanokil katkılı PAN nanolif yüzey elde edilmiştir. Üretilen nanokil katkılı PAN nanoliflerin, taramalı elektron mikroskobu (SEM) ile nanolif boyutları ve lif morfolojileri incelenerek, yaklaşık 950 nm çaplarında oldukları görülmüştür. FT-IR ile kimyasal yapı aydınlatılmaya çalışılmış ve bileşimindeki fonksiyonel grupların varlığı incelenmiştir. Nanoliflerin yapısında PAN ve nanokile ait piklerin oldukları belirlenmiştir. Termal gravimetrik analiz yöntemi (TGA) kullanılarak nanokil katkılı PAN nanolifler termal olarak karakterize edilmeye çalışılmıştır. Çalışılan sıcaklık aralığında iki aşamalı bozunmanın gerçekleştiği ve termal bozunmanın tamamlanmadığı görülmüştür. Nanokil katkılı PAN nanoliflerinden sentezlenen yüzeyin, alternatif bir adsorban madde olarak kullanılabileceği tespit edilmiştir. Anahtar kelimeler: Nanolif, nanokil, PAN (poliakrilonitril), elektrolif çekim , SEM. Synthesis and Characterization of PAN Nanofiber Added Nanoclay Abstract: In this study, nanofibers have been prepared from polyacrylonitril (PAN) polymer by using electrospinnig method which is the most common method to obtain nanofibers. Nanoclay doped PAN nanofiber webs were prepared by sprinkled nanoclay in spinning process of nanofibers which may be used to purpose of adsorption in other study. Diameter sizes and morphology of the produced PAN nanofibers including nanoclay were examined through SEM and it was observed that nanofibers have about 950 nm diameters. The chemical structure has been tried to be illuminated by using FT-IR and the presence of functional groups in this composition have been investigated. It was observed that there were peak belonging to PAN and nanoclay within the structure of nanofibers. PAN nanofibers included nanoclay have been tried to be characterized thermally by using the TGA (thermal gravimetric analysis) method. In the studied range of temperature, it was observed that two-stage degradation occurred and the thermal degradation was not completed. It was determined that the PAN nanofibers were electrospun with nanoclay could be used as a new alternative adsorbent. Key words: Nanofibers, nanoclay, PAN(Polyacrylonitrile), electrospinning, SEM.

In the present study, a heterogeneous adsorbent material (HA) was used as an adsorbent for the removal of Cr(VI) from aqueous solutions at laboratory scale. Cr(VI) containing water was treated with heterogeneous adsorbent(HA).Chromium solutions of various initial concentrations were treated with adsorbent in batch mode experiments to investigate the adsorption characteristics of heterogeneous adsorbent (HA). Kinetics of adsorption of Cr(VI) ions on adsorbent was investigated by using pseudo first order and second order kinetic models. Removal processes were found to be governed by pseudo second order model. Intraparticle diffusion model was also analyzed for this system. Removal was found to be increased by increasing the temperature from 298 to 318 K which indicates the endothermic nature of the process. Various two parameter isotherm models viz. Langmuir, Freundlich, Elovich, Tempkin, Dubnin–Raduskevich (D–R), Harkin–Jura and BET isotherm were applied on resultant data for equilibrium modeling. It was observed that heterogeneous adsorbent (HA) particles were highly efficient for the removal of Cr(VI).

Seventeen edible vegetable oils were analyzed spectrometrically for their metal (Cu, Fe, Mn, Co, Cr, Pb, Cd, Ni, and Zn) contents. Toxic metals in edible vegetable oils were determined by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). The highest metal concentrations were measured as 0.0850, 0.0352, 0.0220, 0.0040, 0.0010, 0.0074, 0.0045, 0.0254 and 0.2870 mg/kg for copper in almond oil, for iron in corn oil-(c), for manganese in soybean oil, for cobalt in sunflower oil-(b) and almond oil, for chromium in almond oil, for lead in virgin olive oil, for cadmium in sunflower oil-(e), for nickel almond oil and for zinc in almond oil respectively. The method for determining toxic metals in edible vegetable oils by using ICP-AES is discussed. The metals were extracted from low quantities of oil (2-3 g) with a 10% nitric acid solution. The extracted metal in acid solution can be injected into the ICPAES. The proposed method is simple and allows the metals to be determined in edible vegetable oils with a precision estimated below 10% relative standard deviation (RSD) for Cu, 5% for Fe, 15% for Mn, 8% for Co, 10% for Cr, 20% for Pb, 5% for Cd, 16% for Ni and 11% for Zn.