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The acid activation process increased the specific surface area of raw Resadiye bentonite (33.5 m2/g) by ∼ 4-fold whereas the interaction with n-butylamine caused a surface area reduction of acid-a...

In this study, the catalyticactivities of raw, some metal cations exchanged (Fe3+ and Cu2+)and Fe- and Al-pillared Artvin bentonite samples as a catalyst foracetalization reaction of benzaldehyde with 2, 3-butanediol were investigated.The structural and physicochemical properties of clay samples were examined byusing X-Ray powder diffraction (XRD), scanning electron microscope (SEM),Fourier Transform infrared (FTIR) and surface area measurement techniques. Theyield of this organic reaction in the presence of Cu-bentonite and Al-pillaredbentonites were found as very low whereas Fe-bentonite and Fe-pillaredbentonite catalysts showed 60 and 63% yield in acetalization under sameconditions, respectively. This study showed that modified Artvin bentonitesamples which is the one member of Turkey’s important local and natural sourcescan be used as catalyst in the selected organic reaction and their utilizationin industrial process reactions in small scale., Bu çalışmada Artvin ham bentonitinin, bazı metal katyonları (Fe3+ ve Cu2+)değiştirilmiş ve Fe- ve Al-sütunlanmış türevlerinin benzaldehitin 2,3-bütandiolile asetalleşme reaksiyonundaki katalitik aktiviteleri araştırıldı. Bukatalizörlerin yapısal ve fizikokimyasal özellikleri X–ışınları toz kırınım(XRD), taramalı elektron mikroskobu (SEM), Fourier transform infrared(FTIR), ve yüzey alanı ölçüm teknikleriyardımıyla aydınlatılmıştır. Cu-bentonit ve Al sütunlu-bentonit katalizörlüreaksiyonlarda verimin çok az olduğu buna karşın Fe-bentonit ve Fe-sütunlubentonit katalizörlerinin kullanıldığı tepkimelerde ise sırasıyla % 60 ve % 63verimle asetalleşme reaksiyonu gerçekleştiği tespit edilmiştir. Bu çalışmaülkemizin önemli yerli kaynaklarından birini teşkil eden Artvin bentonitininmodifiye edilmesiyle organik reaksiyonları katalizleyebildiğini ve bu ürünlerinküçük ölçekte ve endüstriyel proseslerdeki reaksiyonlar içinkullanılabileceğini ortaya koymuştur.

Cellulose aerogel (CA) isolated from tea stem wastes (TSW) is a good fire retardant and heat insulator, environmentally friendly, thermally stable and highly porous material with a network structure. These outstanding properties have attracted a huge interest in the materials world. In this study, firstly, following delignification and removing hemicellulose, pure raw cellulose was isolated using TSW, hydrogel form of cellulose was prepared by regeneration of cellulose solution, and then, the final product (CA) was produced via freeze-drying. The data results showed that the aerogel had a three dimensionally network structure. Moreover, it can be deduced that thermal durability of the studied CA could be effective because of its fire retardant and heat insulating property. In addition, the production process of CA is easily available at low cost and sustainable.

Noble metal nanoparticles including rhodium, ruthenium and palladium have been extensively used in catalysis field. Since their limited abundance and high cost, many methods have been developed to obtain highly active and recyclable catalysts. In this work, Rh3+, Ru3+, Pd2+ ions were impregnated on activated carbon derived from pumpkin stalk in distilled water and then reduced with sodium borohydride to form Rh0, Ru0, Pd0 nanoparticles on the surface of carbon. The analyses show that these nanoparticles were successfully dispersed on the activated carbon. Rh0, Ru0 and Pd0 nanoparticles on activated carbon provide a turnover frequency value of 188 min−1, 235 min−1 and 40 min−1, respectively, at 25.0 ± 0.1 °C. They preserve their activity even after multiple use in H2 generation from the hydrolysis of ammonia borane.

The novel activated carbon materials were synthesized by the carbonization and chemical activation of agricultural bio-waste from tea woody stems (TWS), and these materials were characterized by using FTIR, SEM, TG/DTA and surface analysis (BET surface area; pore distribution; pore size, area and volume) techniques. The higher carbonization times and amount of chemical reagent generally produce the higher surface area at 400 and 500 °C. The experimental data demonstrated that the highest BET surface area was 789 m2 g−1 at 500 °C, 75 μm particle size, TWS/KOH ratio of 1:2 and carbonization time of 3 h. The activated carbon IR spectrum showed the increases in intense of aromatic C–H out-of-plane bending and C=C vibrations and the disappearance of olefinic C=C functional groups. Thermal analysis curves of TWS are ascribed to decomposition of organic derivate corresponding to lignin, cellulose and hemicelluloses components up to 700 °C from 200 °C. The SEM images and textural analysis data signified that the pore development of carbon skeleton structure during carbonization and activation process formed and type of micropores in these pore structures was dominant.

Magnetite nanoparticles-decorated smectite nanocomposite was prepared by precipitation method and the obtained nanocomposite was used as both nanophotocatalyst for removal of rhodamine B from wastewater under UVA irradiation and electrocatalyst for the electrooxidation of chlorite ion on the carbon paste electrode. The raw smectite, bare magnetite and the synthesized nanocomposite catalyst were comparatively characterized by using XRD, FTIR, SEM, EDX, XPS, VSM, TG/DTG, DTA, DSC, electrophoretic mobility and BET techniques in detail. The XRD, SEM, electrophoretic mobility and VSM results indicated that the magnetite nanoparticles were uniformly distributed on the surface of smectite with a diameter of about 7 nm by electrostatic interactions and the prepared nanocomposite displayed well superparamagnetic behaviour with strong saturation magnetization at room temperature. The XPS, EDX, FTIR and thermal analysis data of synthesized nanocomposite further confirmed that the magnetite nanoparticles were successfully decorated on the smectite without formation of another ferric phase species. Furthermore, the surface area of magnetite smectite nanocomposite is higher than that of raw smectite, which is related to the magnetite nanoparticles decorated onto the smectite. The catalytic activities of all samples were comparatively investigated by using the degradation of aqueous rhodamine B solutions as a model pollutant in the heterogeneous photo-like-Fenton process which is well defined by the pseudo-first-order equation in kinetics. The resultant magnetite-smectite nanocomposite showed excellent magnetic separability and much better photocatalytic activity in a short period compared to the bare magnetite and smectite. The synergetic effect between magnetite and smectite showed high activity not only in photodegradation but also in electrocatalytic applications. Because the developed nanocomposite material exhibited enhanced catalytic activity towards to chlorite ion oxidation it was applied for the voltammetric quantification of chlorite ion in aqueous medium. After the optimization of the measurement parameters, the limit of detection and quantification of the method were calculated as 3.0 and 10.0 μM, respectively.

To improve the photocatalytic performance and solve the aggregation problem of BiFeO3 nanoparticles, kaolinite-BiFeO3 photocatalyst was successfully prepared for the first time by decoration of ferromagnetic BiFeO3 nanoparticles onto kaolinite surface. Comparative characteristics of kaolinite, bare BiFeO3 and kaolinite-BiFeO3 photocatalyst were investigated in detail by XRD, TEM, SEM-EDX, XPS, FTIR, VSM, UV-DRS, PL, zeta potential and BET techniques. The photocatalytic activities of the samples were also evaluated by photodegradation of rhodamine B as a model reaction under different irradiations like UVA, visible and sunlight. The kaolinite-BiFeO3 exhibited more superior photocatalytic activity as compared with other samples, which is best fitted to pseudo-first-order kinetic. The reactive species trapping experiments indicated that photogenerated-holes play major roles in the degradation process whereas superoxide radicals possess a secondary effect. Enhanced photocatalytic activity of kaolinite-BiFeO3 is attributed to its kaolinite platform that reduces the recombination opportunities of the photogenerated holes and electrons as well as increases the surface area, decreases the particle size and aggregation of nanoparticles. In addition, we also designed a novel electrocatalytic platform based on gold nanoparticles loaded on kaolinite-BiFeO3 modified carbon paste electrode surface for the examination of electrocatalytic activity for oxygen reduction reaction in alkaline medium. Electrochemical characterizations of the Au/BiFeO3/kaolinite modified carbon paste electrode and other bare surfaces were comparatively carried out with the aid of cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Au/BiFeO3/kaolinite modified carbon paste electrode exhibited 15-fold current enhancement together with 100 mV anodic potential shift compared with bare carbon paste electrode.

Herein, we synthesized ferromagnetic BiFeO3 nanoparticles with sizes of 20–60 nm and rhombohedral distorted perovskite structure without any co-formed impurity phases by sol-gel method. Structural, morphological, magnetic, electronic and textural properties of BiFeO3 nanoparticles were characterized by using XRD, SEM-EDX, TEM, FTIR, XPS, VSM, UV-DRS, PL and BET techniques. The peroxidase was isolated from the Cress (Lepidium sativum) and purified by using precipitation of ammonium sulfate and chromatographic techniques; gel filtration and ion exchange chromatography which is showed wide range of thermal stability, maximum activity in the acidic environment and close to the body temperature. Afterwards, a novel amperometric biosensor based on Cress peroxidase entrapped on BiFeO3 nanoparticles modified carbon paste electrode was prepared for the first time to sensitive detection of H2O2. The prepared H2O2 biosensor was operated with the aid of choro-amperometry technique by applying −0.8 V vs Ag/AgCl electrode. The developed biosensor exhibited a linear response towards to H2O2 in the concentration range of 2.0 10−7 to 1.0 10−5 M under the optimal conditions and limit of detection and quantification were estimated as 7.0 10−8 M (2.7 μg L−1) and 2.0 10−7 M (8.7 μg L−1), respectively. The repeatability of the electrode was calculated as 19.2 for 2.0 10−7 M (N = 7) and the accuracy was 81.2% for this concentration. In addition, the H2O2 biosensor exhibited excellent stability up to ten days. Finally, the sensor developed was used for the analysis of H2O2 in milk samples and satisfactory recoveries were obtained under the operating conditions.

Activated carbons with high porosity and high surface area are promising materials to be used in wide-range applications. They can easily be prepared from various biomass source following by simple and reproducible activation and carbonization steps. In this study, the woody part of tea which is highly available tea waste after the harvesting of tea leaves is considered as the precursor of highly porous activated carbon. In fact, activated carbon with well-ordered porous structure (micropore area = 1614.3 m2 g−1, micropore volume = 1.13 cm3 g−1) and high surface area (2559 m2 g−1) was achieved using this tea waste. The obtained activated carbon was used to support cobalt, nickel and copper nanoparticles which were used as catalysts in H2 generation from aqueous ammonia borane. The results reveal that Co nanoparticles with an average particle size of 3.18 nm on activated carbon provide higher activity (TOF = 7.5 min−1) as compared to nickel (TOF = 4.8 min−1) and copper nanoparticles in this reaction. Herein, we report also the kinetic studies including the effect of temperature, metal concentration and metal loading on the catalytic activity in hydrolysis of ammonia borane.

The molecular structure and the solvent/temperature effect on the tautomerism in a new Schiff base, (E)-4,6-dibromo-3-methoxy-2-[(p-tolylimino)methyl]phenol, were investigated using spectroscopic (NMR, UV–vis, FT-IR), crystallographic (XRD), computational (DFT and TD-DFT) methods and harmonic oscillator model of aromaticity (HOMA). The XRD, DFT and FT-IR results show that the compound exists in the phenol-imine form in the solid state. HOMA indices support the aromatic structure of the compound. DFT calculations were performed to understand proton transfer process and relatively close values were obtained for the energies of tautomers. UV–vis studies prove the solvent dependence of the tautomerism in the compound by revealing the existence of both phenol-imine and keto-amine forms in polar solvents and only the phenol-imine form in apolar solvent. The TD-DFT results for the electronic transitions lead to the same conclusion as the absorption spectra. 1H NMR and 13C NMR studies at room and low (−60 °C) temperatures indicate that the tautomeric equilibrium occurs rapidly in the compound. Therefore, it is difficult to observe two tautomers. However, the presence of tautomeric structures is clearly seen in acetone‑d6, alternatively underlying the solvent and temperature dependence of tautomerism in the title compound.

The present investigation was undertaken to obtain information about the structural, thermal, morphological, surface charge and textural properties of the synthesized dodecyltrimethylammonium-smectite composites at various surfactant concentrations by means of powder X-ray diffraction, attenuated total reflection Fourier transform infrared, thermal analyses, scanning electron microscopy, electrophoretic mobility and surface area measurement techniques. The basal spacing values of organo-smectites varied between 13.55 and 17.00 angstrom that point out the successful intercalation of the surfactant cations into smectite layers with different molecular arrangements either lateral monolayer or lateral bilayer. Intercalation of surfactant cations led to appreciable decreases in the intensities of the bands at 3402 and 1635 cm(-1) which originate from OH stretching and bending vibration of sorbed water molecules, respectively. Thermal analysis data showed that all organo-smectites had lower adsorbed water losses than raw and sodium-smectite and the removal of surfactant species occurred in the temperature range of 130-720 degrees C. The specific surface areas, pore volumes and micropore surface areas of organo-smectites decreased while the average pore width of these species increased with respect to that of raw smectite. The surfactant cations located in the interlayer spaces caused significant alterations in electrophoretic mobility values and morphology of raw smectite. (C) 2015 Elsevier B.V. All rights reserved.

We obtained a low cost and abundant nanopigment material composed of Rhodamine B (Rh-B) organic dye compound and Unye bentonite (UB) clay from Turkey. The characterization of the nanopigment was investigated using scanning electron microscopy (SEM), particle size distribution, powder X-ray diffraction (PXRD), Fourier transformed infra-red spectroscopy (FT-IR) and thermal analysis techniques. According to the result of texture analyses, we showed that the particle size distribution ( d : 0.5-mean distribution) of Rh-B/UB nanopigment material was around 100 nm diameter. It was also demonstrated that the samples had a particle size around nm diameter in SEM images. As seen in the PXRD and thermal analysis, there is a difference in basal spacing by 1.46° (2 θ ) and a higher mass loss by 7.80% in the temperature range 200–500 °C compared to the raw bentonite.

Chitosan-smectite biocomposite was prepared by intercalation of protonated chitosan molecules into the interlayer space of smectite in monolayer arrangement through cation exchange mechanism and the obtained biocomposite was successfully used as an electroactive component in the structure of a PVC membrane potentiometric sensor for the direct and highly selective determination of monohydrogen phosphate ions. The comparative elemental, structural, thermal and morphological analysis of starting-smectite, neat chitosan and chitosan-smectite were investigated by utilizing EDX, XRD, ATR-FTIR, TG/DTG/DTA, SEM and surface area measurement techniques. The optimum membrane composition, detection limit, response time, pH working range and repeatability of the proposed electrode were determined.

WOS: 000331157500036, The expansion by 1.43 Angstrom of basal spacing and the shift to higher frequencies of in-plane ring vibrations of the Pyronin Y molecule at 1603 and 1527 cm(-1) on the formation of Pyronin Y-bentonite composite exhibited that the dye cations might be oriented as a monolayer form in the interlamellar spacing with aromatic rings parallel to clay layers. Thermal analysis results of this composite compared to those of raw bentonite signified the different outer sphere water entities associated with the replacement of inorganic cations with organic dye cations and the gradual decomposition of the organic molecule in the interlamellar spacing. Thermo-Infrared spectra of Pyronin Y-bentonite sample up to high temperatures showed the thermal stability of the dye-clay composite as a result of the presence of it interactions. The pore structure characteristics of Pyronin Y-bentonite composite exhibited the increase in the number of mesopores during formation of the composite. Published by Elsevier B.V., Recep Tayyip Erdogan University and its central laboratory, The authors are grateful to the Recep Tayyip Erdogan University and its central laboratory for the financial and technical supports.

A novel poly(acrylamide-co-methacrylic acid)/organoclay nanocomposite was prepared and its structural, thermal, and morphological properties were investigated by various techniques. The absence of diffraction peaks for the organomodified-smectite nanocomposite showed that dispersion of the clay nanolayers within the polymer matrix was in the form of an exfoliated nanostructure. Morphological studies confirmed that organomodified-clay dispersed homogeneously in the polymer matrix. Infrared spectroscopy results indicated that the organosmectite is physically dispersed in the polymer network without forming any chemical bonds. The thermal analysis data revealed that there are significant increases in temperatures of decomposition and softening points of polymer with addition of organoclay.

The mononuclear six metal(II) complexes ([Co(mef)2(3-pic)2(CH3OH)2] (1), [Ni(mef)2(3-pic)2(CH3OH)2] (2), [Cu(mef)2(3-pic)2] (3), [Co(mef)2(4-pic)2] (4), [Ni(mef)2(4-pic)2] (5), and [Cu(mef)2(4-pic)2] (6) with mefenamic acid and picoline ligands were synthesized, characterized, and their carbonic anhydrase inhibitory activities were evaluated. The six complexes were characterized by elemental analysis, FT-IR spectroscopy, and thermal analyses. The crystal structures of 1, 3, and 6 were determined by X-ray crystallography. The complexes have octahedral geometry. In 1, the mefenamato ligand behaved as monodentate whereas in 3 and 6, the mefenamato ligand acted as a bidentate ligand. Complexes 3 and 6 consist of the mefenamate and 4-picoline ligands. In 1, unlike the other complexes, methanol acted as a ligand and was involved in the coordination. Carbonic anhydrase I and II isoenzymes were purified from human erythrocytes. The in vitro effects of mefenamic acid, 3-picoline, 4-picoline, and the six metal(II) complexes on these isoenzymes were evaluated., The Research Foundation of Erzincan University is acknowledged for the financial support to this work under the Project Number FYL-2017-446.

In this study, ammonium (NH4+) removal from aqueous media was investigated by using bentonit clay. Different concentrations of ammonium ion adsorption from aqueous solutions were examined at a room temperature. Adsorption data were applied to Langmuir and Freundlich models. In addition, the experimental results of adsorption applied to thermodynamic equations of free enthalpy of adsorption process, enthalpy and entropy values were found. Thus, whether voluntary and adsorption effects of temperature on adsorption or not was investigated. In addition, raw and treated clay ammonium (NH4+- bentonite) characterization of samples were established by using thermal analysis and infrared (IR) techniques.

WOS: 000287490500001 The aniline species incorporated into the acid-activated bentonite matrices leads to the decay of the skeletal stretches centered at 1041cm-1 and the rise of new features in the phenyl ring frequency region, 1700-1400cm-1, demonstrates clearly the influence of the acid activation on the Lewis sites necessary for coordination of aniline to bentonite. The exothermic DTA features at 507, 684, and 725 degrees C indicate the release of both the clusters and the decomposed fragments of the aniline-clay composite, and the highly stable carbonaceous residue, respectively. The basal difference by 1.0nm and the much smaller surface area (33.8m2/g) than that of the nonintercalated bentonite (129.2m2/g) prove the presence of the tilted aniline species between the interlamellar grooves of the bentonite framework. Research Foundation of Ondokuz Mayis University [F238] The authors are grateful to the Research Foundation of Ondokuz Mayis University for the financial support of this work under Project F238. We also thank Professor Ugur Cevik of Karadeniz Technical University for performing the chemical analysis of the activated clay sample.

The intercalation of dimethyl sulphoxide (DMSO), pyridine (Py), ethanolamine (Ea), and Nmethyl formamide (NMF) molecules into the kaolinite interlayers led to an appreciable decrease of 3697 cm−1 of the hydroxyl band. The appearance of the peaks at 3662, 3541, and 3504 cm−1 proved that the DMSO species are intercalated between the kaolinite layers through forming H-bonds with internal-surface hydroxyl groups. The intensities of the 942 and 796 cm -1 bending peaks arising from inner-surface hydroxyls decreased and new vibrational features appeared due to the intercalation of the guest species. The d001 value of pure kaolinite was found at 7.18 A° , and the d001 values were seen at 11.26, 11.62, 10.77, and 10.67 °A for kaolinite-dimethyl sulphoxide (K-DMSO), kaolinite-pyridine (K-Py), kaolinite-ethanolamine (K-EA), and kaolinite-N-methyl formamide (K-NMF) composites, respectively. The endothermic differential thermal analysis (DTA) peaks at a temperature of 108 - 334 ◦C reflected the changes in the physicochemical properties of the intercalated species. The thermal stability increase followed the order of K-Py

In this study, the radiological, structural and chemical characterizations of Mardin-Mazidaği phosphate rock, which is an important phosphate fertilizer source in Turkey were investigated and compared to those of several different phosphate rocks of Tunisia, Egypt, Morocco, Algeria and Syria using gamma spectrometry, X-ray diffraction (XRD) and X-ray fluorescence (XRF) measurement techniques. Elemental analysis results of phosphate samples showed that they were mainly composed of CaO, P(2)O(5), SiO(2), Al(2)O(3), SO(3) and Fe(2)O(3). Elemental concentrations of U and Th were calculated using (226)Ra and (232)Th activity concentrations, respectively. As a result of XRD analysis, the main peaks of the samples were found to be Fluorapatite (Ca(5)(PO(4))(3)F). The radioactivity concentration levels for (226)Ra, (232)Th and (40)K in all phosphate samples ranged from 250 to 1029 Bq kg(-1) with a mean of 535 Bq kg(-1), from 5 to 50 Bq kg(-1) with a mean of 20 Bq kg(-1) and from 117 to 186 Bq kg(-1) with a mean of 148 Bq kg(-1), respectively. The computed values of annual effective doses ranged from 0.17 to 0.59 mSv, with a mean value of 0.33 mSv, which is lower than the recommended limit of 1 mSv y(-1) by the International Commission on Radiological Protection.

emirik, mustafa/0000-0001-9489-9093 WOS: 000281458400003 BACKGROUND: The removal of Reactive Red 120 (RR 120) from aqueous solutions using cetylpyridinium modified Resadiye bentonite (CP-bentonite) prepared by ion exchange was investigated with particular reference to the effects of temperature, pH and ionic strength on adsorption. RESULTS: Fourier transform infrared (FTIR) and thermal analysis (TG-DTG/DTA) techniques revealed that the anionic dye (RR 120) molecules replaced partly cationic surfactant species on interacting with CP-bentonite. The positive surface charge originating from the cationic surfactant species located on the external surface of the modified bentonite sample increased at low pH values. The significant amount of dye removal by CP-bentonite at high pH values proved the importance of pi and van der Waals interactions other than the electrostatic attraction in the duration of the adsorption process. The adsorption isotherms and the kinetic data were well described by the Langmuir and pseudo-second-order kinetic model, respectively. The Gibbs energy (Delta G), enthalpy (Delta H) and entropy (Delta S) changes in the temperature range 25-65 degrees C pointed out that the RR 120 uptake increased in parallel with the temperature. CONCLUSION: This study showed that the structural arrangement of cetylpyridinium ions in the CP-bentonite sample as well as the pH, temperature and ionic strength of the bulk solution influenced the adsorption of RR 120 dye from aqueous solutions by CP-bentonite. (C) 2010 Society of Chemical Industry Research Foundation of Rize UniversityRecep Tayyip Erdogan University [2009.102.02.2] The Research Foundation of Rize University is gratefully acknowledged for the financial support to this work under the Project number 2009.102.02.2.

The alumina-dye composites were prepared by treating the basic alumina with the water solutions of Reactive Red 120 (RR 120) and Reactive Blue 15 (RB 15) dyes. The bands of low intensities in the 1400–1600 cm−1 region and at 783 cm−1 in the IR spectra of these composites point out that the dye species is bound weakly to the surface. In the case of mechanochemical adsorption of dye molecules, the asymmetric and symmetric S(=O)2 and the S-O-C stretching bands together with the vibrations of aromatic ring revealed that dye types under dry conditions interacted effectively with alumina surface. After the heating of the alumina dye complexes in the temperature range 150–350°C, the intensities of the IR and XRD peaks for adsorbed types decreased. The endothermic peaks over 200°C and the bigger total mass losses for the alumina-dye composites can be ascribed to the decomposition of dye species retained by the alumina surface. The mass losses on TG curves of the alumina-dye complexes up to ∼800°C exhibit the removal of black residues occurred by decomposition of first adsorbed products. The thermal analysis data also point out that the water molecules bonded strongly to the alumina surface and dye types compete to accommodate at the surface active sites.

This study focused on developing bentonite–cysteine (Bent–Cys) microcomposite affinity sorbents (38–105 μm) for catalase adsorption from aqueous solutions. Pseudo-biospecific affinity ligand l -cysteine was covalently binded onto the bentonite structures. X-ray diffraction and FTIR analysis of Bent–Cys composite affinity sorbents were performed. According to X-Ray diffraction data, cysteine molecule is parallel to the tetrahedral–octahedral–tetrahedral layer (TOT silicate layer) and is a monolayer in the inner layer space of the structure. The surface areas of the Bentonite and Bent–Cys microcomposite structures were found as 33.00 ± 0.30 and 22.80 ± 0.30, respectively. An elemental analysis of immobilized l -cysteine for nitrogen was estimated to be 541.3 μmol g −1 bentonite. Catalase adsorption onto the microcomposite affinity sorbents from aqueous solutions containing different amounts of catalase at different pH was investigated in a batch system. The maximum catalase adsorption capacity of the Bent–Cys microcomposite affinity sorbents was 175 mg g −1 . The non-specific catalase adsorption onto the bentonite was very low (about 2.7 mg g −1 ). The activity yield decreased with the increase of the enzyme loading. It was observed that there was a significant change between V max value of the free catalase and V max value of the adsorbed catalase on the Bent–Cys microcomposite affinity sorbents. The K m value of the immobilized enzyme was higher 1.1 times than that of the free enzyme. Optimum operational temperature was 10 °C higher than that of the free enzyme and was significantly broader. It was observed that enzyme could be repeatedly adsorbed and desorbed without loss of adsorption capacity or enzyme activity.

Temel, Ersin/0000-0002-8822-6674 WOS: 000386021200003 Four new neutral diclofenac-based complexes, [Co(dicl)2(2-pyet)2] 1, [Ni(dicl)2(2-pyet)2] 2, [Cu2(dicl)2(2-pyet)2] 3, and [Cu2(dicl)2(2-pypr)2] 4 have been synthesized and characterized by elemental analysis, FT-IR, thermal analysis. Complexes 1, 3, and 4 have also been characterized by X-ray single-crystal structural analysis. The compounds of Co(II) and Ni(II) have octahedral geometry with two diclofenac and two 2-pyridineethanol ligands in the coordination sphere. The compounds of Cu(II) have square-pyramidal geometry and Cu(II) ions are linked via oxygens to the bridging 2-pyridineethanol or 2-pyridinepropanol ligands. The values acquired by FT-IR are in agreement with the single XRD data. Studies on the thermal properties are reported and the complexes are stable to 196, 216, 215, and 201 degrees C in air, respectively. Two dinuclear Cu(II) complexes have demonstrated catalytic activity on oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone showing saturation kinetics at high substrate concentrations. The diclofenac complexes are investigated as inhibitors of the human cytosolic isoforms hCA I and II. The complexes are good as hCA I inhibitors (Kis of 1.52-55.06M) but only moderately efficient as hCA II inhibitors (Kis of 0.23-5.61M). [GRAPHICS] . Research Foundation of Erzincan UniversityErzincan Binali Yildirim University [110205] This work was supported by the Research Foundation of Erzincan University [grant number 110205].

Bentonite has several advantages for use as a support, including its lack of toxicity, chemical reactivity and hydrophilicity allowing easy fixation of biomolecules. A new approach was developed to obtain an efficient and cost effective purification of IgG from human plasma. This study focused on developing bentonite–histidine micro-composite affinity sorbents (Bent–His) (38–105 μm) for immunoglobulin-G (IgG) adsorption from human plasma. The pseudo-biospecific affinity ligand l -histidine was reacted with covalent binding onto the bentonite structures. X-ray diffraction and FT-IR analysis of Bent–His composite affinity sorbents were performed. The surface area of the bentonite and Bent–His micro-composite structures were found as 33.00 ± 0.30 and 24.70 ± 0.30, respectively. An elemental analysis of immobilized l -histidine for nitrogen was estimated to be 541.3 μmol/g bentonite. The non-specific IgG adsorption onto bentonite structures was negligible (ca. 0.3 mg/g). Higher adsorption values up to 15.6 mg/g were obtained in which Bent–His micro-composite affinity sorbents were used from aqueous solutions. Isotherm studies were carried out to evaluate the effect of initial concentration of IgG, pH and the desorption characteristics of Bent–His micro-composite affinity sorbents. The maximum amount of IgG adsorption from aqueous solution in phosphate buffer was 15.6 mg/g at pH 7.0. A higher adsorption value was obtained from human plasma (up to 89.6 mg/g) with a purity of 94.5%. IgG molecules could be repeatedly adsorbed and desorbed with these micro-composite affinity sorbent systems without noticeable loss in their IgG adsorption capacity.

© 2014, Elsevier. All rights reserved.This study deals with developing bentonite-tryptophan (Bent-Trp) microcomposite affinity sorbent (38-105 μm) for lysozyme adsorption from aqueous solutions. The structural analysis results of Bent-Trp microcomposites obtained from X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), thermal (TG-DTG/DTA) and elemental analysis techniques clearly pointed out that the pseudo-biospecific affinity ligand L-Tryptophan was penetrated into interlayer space of the bentonite by diplacing water molecules and an elemental analysis of immobilized L-Tryptophan for nitrogen was 541.3 μmol g-1 bentonite. The effects of initial concentration, pH, and temperature on the adsorption efficiency of this sorbent were also studied in a batch system. The maximum amount of lysozyme adsorption from aqueous solution was determined as 365.16 mg/g at pH 10.0 and 1.25 mg/mL initial concentration of lysozyme, while the non-specific adsorption of lysozyme was very low (4.21 mg g-1 sorbent). We concluded that Bent-Trp microcomposite affinity sorbents could be repeatedly applied for lysozyme adsorption without significant losses in the adsorption capacity.

Organosmectites were prepared by the intercalation of hexadecyltrimethylammonium cations at various ratios into interlayer of Unye smectite. Structural, thermal, morphological and textural properties of the synthesized organosmectites were characterized. Afterwards, a novel potentiometric PVC-membrane thiocyanate selective electrode was prepared based on the obtained hexadecyltrimethylammonium modified smectites as electroactive material. The basal spacing values of organosmectites were observed in the range of 15.61 and 35.50 A. Powder X-ray diffraction data show that the surfactant cations penetrated into the smectite layers with different molecular arrangements. Modification of smectite with hexadecyltrimethylammonium led to appreciable decreases in the intensities of the FUR bands at 3402 and 1635 cm(-1) and the new characteristic vibrational bands at 2927, 2850, 1472 and 722 cm(-1) originating from the surfactant molecules appeared. The thermal analysis data showed that the decomposition of surfactant species occurred in the temperature range of 170-720 degrees C and the amount of dehydrated water gradually decreased with the increase in surfactant amount. The intercalation of surfactant species within the gallery spacing led gradually to smaller surface areas. In addition, the electrophoretic mobility values indicate that excess surfactant loadings also generate positive charges on the organosmectite surfaces. The most convenient membrane composition resulting in the best potentiometric performance was investigated. The optimum membrane composition was determined to have 20.0% (w/w) 2.5CEC.HDTMA-smectite, 26.0% (w/w) PVC, 54.0% (w/w) DBP The fabricated electrode exhibited a linear response over the thiocyanate concentration range of 1.0 x 10(-4)-1.0 x 10(-1) M (R-2 = 0.9996) with a slope of -48.6 mV/decade. The detection limit, response time and pH working range were determined as 4.3 x 10(-5) M, similar to 10 s and 4-8, respectively. The proposed electrode exhibited selective potentiometric response to thiocyanate comparable to most of the common anions. (C) 2015 Elsevier B.V. All rights reserved.

Aluminium–iron-pillared bentonite has been prepared by incorporation of the iron mixed aluminium-polyoxocation into bentonite layers and characterized by the powder X-ray diffraction, Fourier transform infrared, thermal analysis and surface area measurement techniques. The characteristic d 001 basal spacing of raw bentonite increased with the pillaring process and reached to 18.05 A. The siloxane layers of bentonite were perturbed and the positions of Si–O stretching vibrations were altered by pillaring process. However, these pillars in the interlayer gallery spacing enhanced the thermal stability of bentonite. The new micropores were formed by the pillaring process and the specific surface area of raw bentonite increased by ca. 2-fold for aluminium–iron-pillared bentonite. FTIR spectra and thermal analysis curves of pyridine adsorbed samples clearly show that the surface Lewis acidity of aluminium–iron-pillared bentonite is greater than that of raw bentonite. Raw and aluminium–iron-pillared bentonites have been utilized as solid catalysts for benzoylation of benzene with benzoyl chloride. The aluminium–iron-pillared bentonite catalyst showed promising catalytic activity whereas raw bentonite showed no catalytic activity in benzoylation of benzene with benzoyl chloride.

A new three-dimensional (3D) metal organic framework, [Zn2(μ4-o-pda)2(μ-abpy)]n (1), has been synthesized by the hydrothermal reaction and characterized by FT-IR spectroscopy, elemental analysis, thermal analysis, X-ray powder diffraction, and single crystal X-ray diffraction techniques (o-H2pda = o-phenylenediacetic acid and abpy = 4,4′-azobis(pyridine)). Single crystal X-ray diffraction study reveals that complex 1 exhibits a binodal (3,7)-connected three-dimensional framework (3D) with the point symbol of (3.52)(32.44.57.67.7). Thermal analysis reveal that complex 1 is stable up to 300 °C. In order to investigate the potential of 1 in gas storage applications, we performed experiments and atomically detailed simulations to obtain H2 adsorption isotherm at a pressure range of 0–1 atm at 77 K.

Cirak, Cagri/0000-0002-4717-8602; WOS: 000313601100003 A novel hybrid organic-clay material was prepared by grafting of pyridine-2-methanol in the interlayer space of kaolinite by using a kaolinite/methanol compound as an intermediate. A kaolinite/methanol compound was obtained by guest displacement process of a kaolinite/N-methylformamide pre-intercalation complex with methanol. The structural, morphological and thermal properties of the hybrid material and intermediate species were examined by using X-ray powder diffraction, Fourier transform infrared, thermal analysis, scanning electron microscopy and surface area measurement techniques. The X-ray powder diffraction patterns showed that the penetration of pyridine-2-methanol between the kaolinite/methanol layers caused the emergence of a new peak at 6.51(20) with the distance of 13.57 angstrom. The pyridine-2-methanol species present in the kaolinite interlayers led to appreciable decreases in the intensities of the peaks at 3696, 3667, 3650 and 938 cm(-1) which originate from inner-surface hydroxyl groups of pure kaolinite and the new vibrational peaks belonging to the guest molecule were appeared. The thermal analysis data confirmed that the removal of intercalated species occurred in the temperature range 100-180 degrees C, whereas the grafted pyridine-2-methanol molecules remained stable up to 350 degrees C which may be explained by grafting of the pyridine-2-methanol molecules onto the inner-surface hydroxyls on the interlayer surfaces of kaolinite through Al-O-C covalent bond formations. The organic molecules located in the interlayer spaces caused significant alterations in the morphology of the pure kaolinite. The specific surface areas of the kaolinite-methanol and kaolinite-N-methylformamide compounds increased whereas that of kaolinite/pyridine-2-methanol hybrid material decreased with respect to that of pure kaolinite. (c) 2012 Elsevier B.V. All rights reserved.

A novel N-pyridin-2-ylmethylsuccinamic acid-functionalized smectite nanomaterial was synthesized by immobilizing of N-pyridin-2-ylmethylsuccinamic acid through chemical bonding onto (3-aminopropyl)triethoxysilane modified smectite. The structural, thermal, morphological and surface properties of raw, silane-grafted and the N-pyridin-2-ylmethylsuccinamic acidfunctionalized smectites were investigated by various characterization techniques. The thermal analysis data showed the presence of peaks in the temperature range from 200 °C to 600 °C due to the presence of physically adsorbed silanes, intercalated silanes, surface grafted silanes and chemically grafted silane molecules between the smectite layers. The powder x-ray diffraction patterns clearly indicated that the aminopropyl molecules also intercalated into the smectite interlayers as bilayer arrangement whereas N-pyridin-2-ylmethylsuccinamic acid molecules were only attached to 3-aminopropyltriethoxysilane molecules on the external surface and edges of clay and they did not intercalate. Fourier transform infrared spectroscopy confirms N-pyridin-2- ylmethylsuccinamic acid molecules bonding through the amide bond between the amine group of aminopropyltriethoxysilane molecules and a carboxylic acid functional group of N-pyridin-2- ylmethylsuccinamic acid molecules. The guest molecules functionalized onto the smectite caused significant alterations in the textural and morphological parameters of the raw smectite. The anchoring of N-pyridin-2-ylmethylsuccinamic acid molecules led to positive electrophoretic mobility values when compared to starting materials. N-pyridin-2-ylmethylsuccinamic acidfunctionalized smectite was employed as an electroactive ingredient in the structure of potentiometric PVC-membrane sensor. The sensor exhibited more selective potentiometric response towards chlorate ions compared to the other common anionic species.

WOS: 000293118100017, The molecular aggregation and spectroscopic properties of Pyronin Y (PyY) in the suspension containing natural bentonite clay were studied using molecular absorption, steady-state and time-resolved fluorescence spectroscopy techniques. Interaction between the clay particles and the cationic dye compounds in aqueous solution resulted in significant changes in spectral properties of PyY compared to its molecular behavior in deionized water at the same concentration. These changes were due to the formation of dimer and aggregate of PyY in the clay suspension as well as the presence of the dye monomer. The H-type aggregates of PyY in the clay suspension were identified by the observation of a blue-shifted absorption band of the dye compared to that of its monomer. In spite of diluted dye concentrations, the H-aggregate of PyY in the clay suspension was formed. The intensive aggregation in the clay suspension attributed to the localized high dye concentration on the negatively charged clay surfaces. Adsorption sites of PyY on the clay particles were discussed by deconvulated absorption and excitation spectra. Fluorescence spectroscopy studies revealed that the fluorescence intensity of PyY in the clay suspension is decreased by H-aggregates drastically. Moreover, the presence of H-aggregates in the clay suspension resulted in the decrease of fluorescence lifetime and quantum yield of PyY compared to those in deionized water., Ataturk University; Rize University, The authors thank the Research Fund of Ataturk University and Rize University for the financial support of this work.

SARIHAN, Adem/0000-0003-1809-7034; WOS: 000296950300036 The difference in the basal spacing (8.79 angstrom) and a higher mass loss (6.2%) in the temperature range of 200-750 degrees C of naproxen-bentonite (N-bentonite) comparing to that of Unye bentonite (UB) signified the existence of thermally stable organic species in the interlamellar space of the bentonite clay. The asymmetric OCO- stretching band (1607 cm(-1)) of N-bentonite became stronger in the temperature interval of 100-400 degrees C as a result of binding via the C=O group of the ligand to exchangeable cation and/or water molecule whereas the OH bending peak of water (1633 cm-1) and the C=C stretching vibration of aromatic ring (1531 cm(-1))became weaker on thermal treatment. The effect of ionic strength on the desorption of naproxen species and the related kinetic data revealed that the release mechanism at pH = 7.4 is unrestricted diffusion controlled and governed by the repulsive interactions between the bentonite surface and the negatively charged species. The pore structure characteristics of the bentonite samples corresponding to the surface area, pore volume and pore size were determined by using the conventional analysis of the nitrogen adsorption-desorption isotherms. (C) 2011 Elsevier B.V. All rights reserved.

This paper presents the adsorption of Cu(II) ions from aqueous solution on modified Unye bentonite. Adsorption of Cu(II) ions by magnesium oxide-coated bentonite (MCB) sample was investigated as a function of the initial Cu (II) concentration, solution pH, ionic strength, temperature and inorganic ligands (Cl-, SO42-, and HPO42-). Changes in the surfaces and structure were characterized by means of XRD and N-2 gas adsorption data. The Langmuir monolayer adsorption capacity of MCB in 0.1 M KNO3 solution was estimated as 58.44 mg/g. Delta G, Delta H and Delta S values were evaluated for MCB to be -9.50 kJ/mol (at 303 K), 43.81 kJ/mol and 175.85 J/mol K. (C) 2010 Elsevier B.V. All rights reserved.

WOS: 000262292400067 PubMed ID: 18534746 Reactive Blue 15 (RB 15) adsorption on the Turkish Sepiolite was carried out by batch equilibrium technique. IR spectrum and surface area measurement of the composite of dye-sepiolite (Turkish) pointed out that dye species replaced partly the zeolitic water to form hydrogen bond with bound water and adsorbed to the channels sites. The effects of temperature, pH and ionic strength on adsorption of dye molecules were investigated and the nature of adsorption process was determined by calculating Delta H, Delta S and Delta G values. The adsorbed amount increased with increase in temperature, but that for high pH values decreased for the adsorption of reactive dye. (C) 2008 Elsevier B.V. All rights reserved.

WOS: 000244313900017 Organobentonites were synthesized by treating Na-bentonites (Wyoming and Resadiye) with cetylpyridinium chloride (CPC) using ion exchange method. The difference in the basal spacing by 0.65 angstrom and a higher mass loss by 13.32% of organobentonite (Wyoming) in the temperature range 200-550 degrees C comparing with that of organobentonite (Resadiye) were in conformity with the CEC values of organobentonites. The HOH stretching and bending peaks of bentonites became sharper following the treatment with the organo-cation. The intensity decrease of the Al-OH band for organobentonite (Resadiye) and in particular, the significantly higher amount of m-cresol retained by the organobentonite of lower CEC than that by the organobentonite (Wyoming) indicate the influence of the CP cation on the adsorption process.

WOS: 000248351900002 PubMed: 17531244 The shifts of the Si-O-Si stretching and the Si-O-Al and Si-O-Si bending modes, as well as the free silica peak in the IR spectra and the strengthening of the XRD reflections due to the quartz and alpha-cristobalite components of the Al-pillared bentonites (Wyoming and Resadiye), are ascribed to the formation of new Si-O-Al groups of covalent character. The mass losses in the temperature range 150-700 degrees C correspond to the dehydration and dehydroxylation processes. The total mass losses of the Al-pillared bentonites (Wyoming and Resadiye) are close to each other at an OH/Al ratio of 2.2, but calcination from 400 to 600 degrees C causes the surface area of the latter composite to decrease by 13%. (c) 2007 Elsevier Inc. All rights reserved.