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This study evaluated boron diffusion from rods made of raw boron minerals, ulexite and colemanite with low water solubility, in comparison with di-sodium octaborate tetrahydrate (DOT). Scots pine (Pinus sylvestris L.) sapwood and heartwood blocks were conditioned to target moisture contents of 30%, 60%, and 90%. The rods were inserted into the blocks through treatment holes and boron diffusion was observed at three assay zones across the blocks after 7, 30, 60 and 90-day-incubation at room temperature. Ethylene glycol was also inserted into the holes to improve boron diffusion. Boron levels increased with increased wood moisture content. With some exceptions, boron in the assay zones did not tend to follow consistent amount gradients with distance from the treatment hole. Boron levels from ulexite rods were higher than those from colemanite rods, with DOT rods with the highest diffusion rates as a result of higher water solubility of DOT than ulexite and colemanite. The results suggest that ulexite-based rods may be useful in the presence of ethylene glycol in sapwood when wood is at high moisture content for extended periods.

Ultrasound-assisted research on both synthesis and in-situ hydrolysis of ammonia borane (NH3BH3) for hydrogen energy application was experimentally investigated in this study. The salt metathesis reaction between sodium borohydride (NaBH4) and ammonia sulfate ((NH4)(2)SO4) in the presence of organic solvent, tetrahydrofuran (THF), was performed to NH3BH3 synthesis by application of ultrasound. Specifically, the effect of molar ratio (0.96 - 1.06), solvent volume (100-300 ml), time (40-160 min) and temperature (20-60 degrees C) on yield was evaluated to optimize the reaction conditions. The effect of drying process was also assessed under specified conditions, and chemical structures of synthesized samples were compared with commercial supplied NH3BH3. The present investigation provided data on the crystal, and chemical properties of lab-made NH3BH3 and results confirmed the promoting effect of ultrasound on synthesis with excellent yield-96 wt. %. Moreover this, hydrogen deposition characteristits of concentrated lab-made NH3BH3 solutions (5 - 25 wt.%) were assisted by ultrasound to evaluate hydrogen by in-situ reaction in the presence of active metals (Co2+, Ni2+, and Cu2+-). (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

In this study, a mesoporous carbon (CMK-3) was successfully synthesized using mesoporous silica (SBA-15) prepared from gold mine tailings (sample CGMT) for removal of anionic dye from aqueous solution. For comparison, CMK-3 was prepared by the same method from pure silica (sample CT), and the other CMK-3 sample was prepared by a one-pot route mixing with Pluronic P123 (sample CP). The effect of the carbonization time on the synthesis of all CMK-3 samples was investigated, and the samples were characterized by X-ray diffraction and N2 adsorption–desorption. The sample with the highest surface area was chosen as an adsorbent, for each CMK-3 obtained from different methods. Batch adsorption experiments were studied to determine the influence of pH, contact time, and initial dye concentration. The adsorption kinetics obeyed the pseudo-second-order model. All carbon-based adsorbents were observed to be quite effective for the removal of dye with adsorption percentage in the order of CP > CT > CGMT. The maximum adsorption capacities were 188.99 and 204.57 mg·g−1 for CT and CGMT, respectively. The comparative results of all carbon-based adsorbents show that CGMT can be applied as a low-cost alternative to CT for dye removal. HIGHLIGHTS CMK-3 was synthesized from gold mine waste (CGMT) for the first time.; The usage of CGMT as low-cost adsorbent for the removal of dye was investigated.; For comparison, other adsorbents synthesized from different methods were investigated as an adsorbent in the dye adsorption.; The specific surface area, pore volume and pore size dominate the adsorption capacity.; CGMT can be applied as a novel, low-cost and alternative adsorbent for dye removal.

Cobalt-boron loaded thermal activated sepiolite composites (Co-B@tSe) are prepared with an impregnation-chemical reduction method and calcination step for use as a catalyst for sodium borohydride (NaBH4) hydrolysis, solvolysis, and methanolysis. The catalytic activity of Co-B@tSe can be improved by using a thermal-treated raw sepiolite as a catalyst support (Eskisehir, Turkey). The catalysts are analyzed using XRD, XRF, FT-IR, BET, DTA/TG, SEM/EDS and, TEM measurements. The catalytic performance for hydrogen generation is evaluated at room temperature. Research shows that cobalt-impregnated, heat treated, raw sepiolite at 500 °C (Sample B-2) exhibits a high boron loading ability. These conditions, in conjunction with an appropriate calcination treatment, can improve catalytic activity. When the Co-B@tSe, in the form of Co3BO5 sized 6 ± 1.8 nm, is dispersed on sepiolite channels, the catalyzed hydrogen generation rate (HGR) shows a trend of more methanolysis than hydrolysis at room temperature.

Magnesium wastes are among the gradually ascending and therefore challenging metal wastes, which are produced by many industrial activities. The purpose of this study is the usage of magnesium waste, a raw material in magnesium borate production by hydrothermal synthesis. Boron sources (boric acid (H3BO3) and boron oxide (B2O3)) react with magnesium wastes in order to synthesize the magnesium borate mineral of admontite (MgO(B2O3)3.7(H2O)). In addition to the synthesis from waste magnesium, magnesium oxide (MgO) and B2O3 are also used to produce magnesium borates, in order to compare the results. Techniques of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and scanning electron microscopy with energy disperse (SEM-EDX) are used for further characterization analysis. The products boron oxide contents and overall yields are also calculated. According to the results, synthesized minerals are identified as admontite (MgO(B2O3)3.7(H2O)), mcallisterite (Mg2(B6O7(OH)6)2.9(H2O)) and magnesium borate hydrate (MgB6O7(OH)6.3(H2O)). It is seen that magnesium borates could be obtained as a mixture of different types of magnesium borate minerals or pure magnesium borate. A pure magnesium borate mineral of admontite is synthesized at the reaction temperature of 100oC and the reaction time of 240 minutes using magnesium waste (W) and both H3BO3 (W) and B2O3 (B). B2O3 content and overall yields of pure admontite for the W-H were found as 51.15 0.52% and 81.45 3.20%, respectively. Similarly, pure admontite synthesized from W-B have the 51.72 0.52% of B2O3 content and 74.56 3.20% overall reaction yield.

This study was focused on synthesis of zeolite X from coal fly ash using the alkaline fusion method coupled with a novel method which uses ultrasonic energy for aging step. Optimum conditions were investigated using the Taguchi experimental design method. Synthesized zeolitic products were characterized by X-ray diffractometry, scanning electron microscopy, surface area, and cation exchange capacity analysis. Aging time was reduced from 24 to 2 h with usage of ultrasonic energy. Due to high surface area and similar crystal and morphological properties of the final products, we propose that the synthesized zeolitic products can serve as commercially competitive available material.

Terzi, Evren/0000-0003-4133-8852; KANTURK FIGEN, AYSEL/0000-0002-0930-9704 WOS:000576938300004 Boron-based rods are ideal for remedial treatments in wood attacked by decay fungi, insects and termites as well as for preventive treatments of high-risk areas in structural timbers and logs internally. This study evaluated the solubility, some physical and thermal properties of the boron-based rods manufactured from either raw ulexite mineral, raw cole-manite mineral, di-sodium octa borate tetrahydrate (DOT), and their combination of silica-based plasticizer. This is the first attempt to produce ulexite and colemanite-based boron rods with/without additional compound by an extruder. To take the advantages of boron minerals, rods were produced with paste mixtures of boron compounds and plasticizer by a single-screw extrusion method. Solubility and thermal resistance tests as well as micro-hardness tests were performed to determine the quality and strength of the rods for discussing the on-site applications. The paste content was an important factor affecting the transport processes during single screw extrusion with special emphasis on the rod formation. No macro-structural changes were observed when the boron rods were exposed to heat at 30, 50, 70, 100, and 200 degrees C. According to the Kruskal-Wallis test, no significant difference was observed in micro-hardness values of thermally treated boron-based rods; however, at high temperatures up to 50 degrees C, there was a decrease in hardness of DOT rods. The rods manufactured by extrusion methods showed similar water solubility when compared to raw ulexite and colemanite minerals. TUBITAK (The Scientific and Technological Research Council of Turkey) under 1005-National New Ideas and Products R&D Funding ProgramTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [1160149]; Yildiz Technical UniversityYildiz Technical University [FYL-2017-3107] The boron compounds used were supplied by Eti Maden, Ankara, Turkey. The boron rods were manufactured at Remsan Refractory Material Industries Inc., Istanbul, Turkey. The work was supported by TUBITAK (The Scientific and Technological Research Council of Turkey) under 1005-National New Ideas and Products R&D Funding Program (Project No. 1160149) and by Research Fund of the Yildiz Technical University (Project No. FYL-2017-3107).

In the present study, thermolysis characteristics and kinetics of ammonia borane–boron composites for hydrogen production were reported. Composites were prepared by ball milling neat ammonia borane with varying weight ratios of 20, 50, and 80 wt% of boron derivatives, namely boric acid and boron trioxide. Differential scanning calorimetry system was used to measure hydrogen production and determination of first hydrogen releasing temperature. Activation energy of composites decomposition was calculated by using several models, such as Kissinger, Ozawa–Flynn–Wall, and ASTM E 698 methods.

In this study, MCM-41 was prepared from the gold mine tailings slurry as an alternative silica source. The effects of the reaction time, temperature, and pH adjustments on the synthesis of MCM-41 were investigated. The optimum condition for the synthesis process of pure and highly ordered MCM-41 from tailings slurry was found to be at 30?C for 60 min with a pH of 11. In addition, MCM-41 was synthesized from a pure silica source, in order to compare the structural properties of the obtained sample from that of the slurry produced at optimum conditions. The samples synthesized from tailings slurry had a high surface area of 983 m2/g and a pore volume of 0.74 cm3/g. The structural properties of the samples produced from the slurry were closely related with those that were synthesized from a pure silica source. Results indicate that the tailings slurry has the potential to be used as a cheap, alternative silica source which can be used for the synthesis of a pure and ordered mesoporous silica MCM-41.

The objectives of the study were to investigate the devolatilization kinetics of olive leaves and their utilization as precursors for activated carbon. The devolatilization process was performed using thermogravimetric analysis under nitrogen at heating rates of 10, 15, and 20°C min−1 with kinetic evaluation by the Coats-Redfern and Horowitz-Metzger methods. Potassium hydroxide activated olive leaves were employed as precursors for the production of activated carbon at 700°C for 60 min. Brunauer–Emmett–Teller and infrared spectroscopy were used for the characterization of texture and chemical properties of activated carbon. The adsorption capacity of fabricated active carbon with 1422 m2 g−1 surface area for methyl orange was characterized and data fitted well with a Langmuir model (R2 = 0.9977). The monolayer adsorption capacity of the activated carbon on methyl orange was 714.86 mg g−1 and the kinetics followed a pseudo-second-order model.

Green bean (Phaseolus Vulgaris L), classified under legume family, is a primary source of dietary protein in human diets especially in the agricultural countries. Green bean is susceptible to rapid deterioration because of their high moisture content and in order to prevent and present the green bean drying process is applied. In this study, effects of pretreatments on drying kinetics, colour and rehydration capacity of green bean were investigated. It was observed that the pretreatment affected the drying time. The shortest drying times were obtained from pretreated samples with blanched. Drying times were determined as 47, 41 and 29 h for natural, salted and blanch, respectively. The results showed that pretreatment and ambient temperature significantly (P = 0.05) affected the drying rate and the drying time. The effective moisture diffusivity was determined by using Fick’s second law and was found to be range between 3.15 × 10−10 and 1.2 × 10−10 m2/s for the pre-treated and natural green bean samples. The rehydration values were obtained 2.75, 2.71, 2.29 (g water/g dry matter) for the blanched, salted and natural samples. The effective diffusion coefficients were calculated using the data collected during the falling rate period and the experimental data are fitted to seven thin layer drying models which found in the literature. The Logarithmic model was found to best describe the drying behavior of fresh green beans under open air sun. Rehydration time and color parameters had been determined in order to improve the quality of dried green bean. Regarding with rehydration time and colour data, the best results were obtained at blanched drying conditions.

In the present study, SBA-15 silica materials synthesized from different silica sources (S15T and S15S) and functionalized by post-grafting method with trimethylmethoxysilane (F-S15T and F-S15S) were compared as drug carriers for flurbiprofen (FBP). The physical state of the drug in the samples was characterized by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). The results showed that the FBP molecules were not arranged in a crystalline form after incorporation of FBP into the pores of the SBA-15 samples. Surface functionalization resulted in decreased surface area, pore size, and pore volume of S15T and S15S, which decreased the drug-loading capacity from 27.09% to 13.59% and from 16.96% to 9.19%, respectively. The in vitro drug release testing demonstrated that functionalized SBA-15 samples showed slower release rates compared to the non-functionalized samples. The results indicate that F-S15T (which had the smallest pore size) showed controlled drug release profiles without burst-release while the other silica samples showed faster release profiles than F-S15T, indicating that pore size and hydrophobicity influenced the rate of the drug release process. The drug release mechanism of all the samples was found to be Fickian diffusion.

This study has investigated the antimicrobial potential of ring opening metathesis polymerization (ROMP)-based hydrogels. Initially, double charge containing cationic (DABCO)-ROMP polymers were synthesized and characterized. Subsequently, DABCO-ROMP polymer was added into a hydrogel formulation comprised of acrylamide (AAm), N,N’-methylenebis(acrylamide) (BAAm) and/or poly(ethylene glycol) diacrylate (PEG diacrylate, M n = 700 g/mol) in different quantities to investigate the antimicrobial efficiency of the hydrogel formulations. N,N,N',N'-tetramethyl ethylene diamine (TEMED) is used with ammonium persulfate (APS) to catalyze polymerization in water. The structures of the resulting hydrogels were characterized using infrared spectroscopy (IR). The cross-linking properties and surface morphologies were investigated via the swelling behavior and scanning electron spectroscopy (SEM). Fluorescein (Na salt) staining measurements were also used to analyze the positive charge density of the hydrogels. The antimicrobial hydrogels showed excellent antimicrobial efficacy against Escherichia coli (E. coli, ATCC 25922), Staphylococcus aureus (S. aureus, ATCC 29213) and Candida albicans (C. albicans, ATCC 90028). It was observed that the cationic ROMP polymer in the hydrogel formulation played a crucial role in the biocidal activity. Furthermore, cytotoxicity studies on human umbilical vein endothelial cells (HUVEC) and tetrazolium salt assay (MTS) cell lines were also performed on the hydrogels and the most potent copolymer revealed no cytotoxicity. Therefore, the ROMP-based hydrogels show good biocidal properties with potential applications in various biomedical fields. © 2019 Elsevier Ltd 2013-07-01-KAP04, 2016-01-02-KAP03 We gratefully acknowledge the financial support provided by the Yildiz Technical University Projects Office (Project No: 2013-07-01-KAP04 and project no: 2016-01-02-KAP03 ). We thank to Şule Dinç, Aylin Kaymaz and Esra Altay for experimental assistance for the synthesis of ROMP polymer. We also thank Behlül Çuhalı for useful discussions and technical assistance for the preparation of photographs.

The hydrothermal synthesis of copper borate compounds [Cu(BO2)2] was studied, and several parameters were found to affect the synthesis. Raw materials, including CuSO4·5H2O, Na2B4O7·5H2O, Na2B4O7·10H2O, NaOH and H3BO3, were used. Reaction temperatures and reaction times between 40 °C and 100 °C and 15 and 240 min, respectively, were used. The as-synthesised copper borate was analysed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The yields of the reactions were also calculated. Single-phase, nanoparticulate copper borate compounds (Cu(BO2)2) possessing high XRD crystal scores were obtained; the reactions used to obtain these materials were highly efficient. Electrical resistivity and optical absorbance measurements were carried out on the compounds obtained from the highest yielding reactions. The results of this study showed that even using a reaction time of 15 min, copper borate formation was successfully achieved.

Doymaz I., Kipcak A.S., Piskin S. (2015): Microwave drying of green bean slices: drying kinetics and physical quality. Czech J. Food Sci., 33: 367–376. Several microwave power settings were applied to green beans in order to determine the effect on the drying kinetics along with the rehydration ratio and colour values. In the experiments, several microwave power settings were studied as 180, 360, 600, and 800 W. From the results, it is seen that the level of microwave power affected the drying kinetics, rehydration ratio, and colour of the beans slightly. The nine best known thin-layer drying models that were used in literature were applied to the experimental data and the results showed that Midilli et al. model best fits the experimental data for the drying kinetics of green bean slices. Effective moisture diffusivity was found to be between 1.387 × 10 –8 and 3.724 × 10 –8 m 2 /s. Using modi fied Arrhenius type equation the activation energy was found as 19.185 kW/kg. The rehydration ratio of samples dried at 800 W was higher than those of samples at other power settings. It was observed that an increase in the microwave power increased the brightness and yellowness, on the contrary, it decreased the greenness of the dried samples.

In the present study, magnesium borate synthesis was performed by a hydrothermal mixing method, with the use of magnesium waste scraps (W) as the magnesium source, along with boric acid (H) or boron oxide (B) as the boron source. For an environment-friendly approach, a solid waste of magnesium was used at low reaction temperatures. Results of X-ray diffraction analyses showed that admontite [MgO(B2O3)3·7(H2O)] and mcallisterite [Mg2(B6O7(OH)6)2·9(H2O)] types of magnesium minerals were obtained from the synthesis. Through Fourier transform infrared spectroscopy and Raman spectroscopy, in both the infrared and the visible regions, characteristic borate bands were observed. The results of the boron oxide content analyses were in agreement with literature data. The particle sizes, obtained by scanning electron microscopy analyses, were found within the range of 200 nm to 2 μm for mcallisterite and 210 nm to 2.5 μm for admontite minerals. The reaction yields of the minerals were calculated in the range of 16.6–82.0% for the experiments on waste magnesium and boric acid, whereas for the experiments on waste magnesium and boron oxide these were 12.7–78.8%.

In the present study, waste Mg based material (W/Mg) was used as a raw material for the generation of hydrogen. Ball milling and saline solution method were performed to ensure full completion of the hydrolysis reaction. Improved texture properties were obtained by ball milling W/Mg for 15 h (2.29 m 2 g −1 BET area, 11.94 μm particle size). Ball milled W/Mg was used to generate hydrogen gas in the presence of various saline solutions (1 M NiCl 2 , CoCl 2 , CuCl 2 , FeCl 3 , and MnCl 2 ). While hydrogen generation was not observed in pure water, maximum conversion (100%) was achieved in 1 M NiCl 2 solution.

The development of highly efficient catalysts for hydrogen evolution has a crucial significance due to adaptation for sustainable clean energy systems. This study provides potentially powerful approach for catalytic hydrogen evolution based on ammonia borane (NH3BH3) hydrolysis in presence of ternary metal nanoparticles (TMNPs). Herein, we draw up a strategy by using non-noble (Ni, Ag) and noble (Ru, Pt, Pd and Rh) metal promoters in the structure of Co-Cu nanoparticles to boost their catalytic activity for hydrogen evolution by NH3BH3 hydrolysis. Internal and external properties of TMNPs catalysts are characterized by using XRD, SEM/EDS, FTIR, XPS, XRF, ICP-OES, BET, TEM and SAED/HRTEM techniques and performed for hydrogen evolution tests. Kinetic and thermodynamic assessments, bimolecular reaction mechanism investigation and reusability-recyclability-stability performance results relieve that Rh promoted CoCu TMNPs delivers highest hydrogen evolution activity with 21.21 l H-2 g(-1) cat min(-1), 8582 mol(H2) mol(cat)(-1) h(-1) initial turnover frequency (TOF) value, and 36.50 kJ mol(-1) activation energy (E-a) by providing the release of 3 equivalent H-2 per mole of NH3BH3 even after 10th use of catalytic performance tests.

The use of raw boron minerals (i.e. tincalconite, colemanite, and ulexite) was evaluated to increase the fire performance of wood plastic composites (WPCs) in comparison with commercially available fire retardants (FRs). Cone calorimetry and limited oxygen index tests were performed to evaluate the fire properties of WPC specimens. Artificial weathering and 3-point bending tests were also performed on the test specimens loaded with the highest loading level of FRs. The most important decrease in the heat release rate values was 42% and 40% in the magnesium hydroxide- and colemanite-added WPCs at a loading level of 15% (w/w), respectively. Incorporation of colemanite and ulexite into the WPCs increased the limited oxygen index levels by nearly 13% at the same loading level. An increase was observed in the peak heat release rate values in all of the WPC specimens after accelerated weathering. All of the FRs had statistically improved MOE values compared with the control WPC specimens. In particular, the incorporation of zinc borate and borax increased the MOE values by approximately 48% and 42%, respectively. Similar to the effect on the MOE values, zinc borate and borax improved the modulus of rupture the most (approximately 18%).

A new hybrid of nanoparticles designed to enable efficient catalysis for hydrogen generation (NPs) include a dual combination of Co, Ni, and Cu transition metals. These nanoparticles are made by altering metals and molar ratios (x: 0.25, 0.50, and 0.75) and synthesized for hydrogen generation by hydrolytic dehydrogenation of ammonia borane (NH3BH3). A synergistic effect of dual combination on the induction period and dehydrogenation rate (DR) is found. Kinetic interpretation and thermodynamic studies demonstrate that the Co0.50Cu0.50/NPs catalyst shows superior activation (DR = 10.56 l H2 min−1.g−1cat and Ea = 38.12 kJ mol−1) with a synergistic effect and meet the criteria of The United States Department of Energy (DOE) targets for onboard hydrogen production systems for light-duty vehicles.

Mesoporous SBA-15 was synthesized from tetraethyl orthosilicate and sodium silicate as pure silica sources and waste gold mine treatment sludge as an alternative silica source. The synthesis of SBA-15 samples were carried out by the hydrothermal method using the silica source and Pluronic P123 triblock copolymer as the structural template in an acidic medium. The synthesized materials were characterized by X-ray diffraction and nitrogen adsorption–desorption analysis. Thermal decomposition behaviors and kinetics of template from as-synthesized SBA-15 samples derived from different silica sources were investigated by thermogravimetry. The activation energies to decomposition of the template from as-synthesized SBA-15 samples were determined by Vyazovkin model-free method. The decomposition behavior of SBA-15 synthesized from waste was similar to SBA-15 synthesized from tetraethyl orthosilicate. Thermogravimetry coupled with Fourier transform infrared spectrometry analysis was applied for analysis of gaseous products evolved during thermal decomposition of synthesized samples. H2O, CO2, CH2, and CH3 were the main gaseous products released.

Doymaz I., Kipcak A.S., Piskin S. (2015): Characteristics of thin-layer infrared drying of green bean. Czech J. Food Sci., 33: 83–90. The effect of infrared (IR) power on drying kinetics, rehydration, and colour of green beans was investigated. The drying experiments were carried out at 83, 104, 125, 146, 167, and 188 W. It is observed that drying characteristics, rehydration, and colour of bean slices were greatly influenced by infrared power. The drying data were fitted with five thin-layer drying models available in the literature. Results showed that Midilli et al. and Aghbashlo et al. models are superior to the other models for explaining the drying kinetics of green bean slices. Effective moisture diffusivity was calculated in the range of 6.57 × 10–10 to 4.49 × 10–9 m2/s. Activation energy was estimated by a modified Arrhenius type equation and found to be 11.379 kW/kg.

Zinc borate hydrate (Zn3B6O12·3.5H2O) was synthesized from zinc sulfate heptahydrate (ZnSO4·7H2O), anhydrous zinc chloride (ZnCl2), and boric acid (H3BO3). The product was characterized by X-ray diffraction, Fourier-transform infrared and Raman spectroscopy, and thermal gravimetry and differential thermal gravimetry. The effects of reaction time and temperature on product morphology were studied by use of scanning electron microscopy. Results from thermal analysis showed that dehydration occurred in two steps. Thermal dehydration kinetics were investigated by use of the Coats–Redfern and Horowitz–Metzger non-isothermal kinetic methods. In the Coats–Redfern method, activation energies were found to be 225.40 and 570.63 kJ/mol for the first and second steps, respectively. In the Horowitz–Metzger method, activation energies were found to be 254.33 kJ/mol for the first step and 518.22 kJ/mol for the second step.

This research work demonstrates the use of fractional factorial experimental design technique for the novel synthesis of ordered mesoporous silica SBA-15 from the tailings slurry of a gold mine treatment plant. A two-level factorial design was employed to investigate the influence of five factors (weight ratio of NaOH/slurry, leaching time, stirring time, synthesis temperature, and synthesis time) on specific surface area (SBET). The experimental design results show that only the weight ratio of NaOH/slurry influenced SBET significantly and the obtained model predicts the SBET as a function of the weight ratio of NaOH/slurry. The experimental values were in reasonable agreement with the predicted values. It was revealed that fractional factorial design is a suitable tool for investigating the effects of large number factors simultaneously, thus reducing the number of experiments required.

Artan nufus yogunluguna bagli olarak ortaya cikan asiri enerji tuketimi, cevre kirliligi ve kuresel isinma tum dunya icin tehdit olusturmaktadir. Cevresel alanda meydana gelen bu degisimler tum dunyada arastirmacilarin dikkatini cekmekte ve pek cok akademik ortamda calisilan konular arasinda yerini almaktadir. Binalarin termal olarak yalitimi uzun yillardir arastirilip gelistirilen bir konu haline gelmistir. Son yillarda ileri teknolojiler kullanilarak gelistirilen ustun ozellikli yalitim malzemeleri, uzun yillardir kullanimda olan geleneksel yalitim malzemelerinin yerini almakta ve ticari bir pazar yaratmaktadir. Bu calismada ultrasonik destekli sol-jel yontemi kullanilarak, ucuz ve kolay ulasilabilir bir malzeme olan kumdan, hidrofobik ozellikli aerojel uretimi gerceklestirilmistir. Aerojelin modifikasyon islemi uretim sirasinda gerceklestirilmis ve tum kurutma islemleri super kritik basinc kullanilmadan ortam basincinda tamamlanmistir. Cesitli uretim parametrelerinin elde edilen aerojelin yogunlugu uzerine olan etkisi incelenip en dusuk yogunluktaki malzemenin sentezlendigi kosullar optimum kosullar olarak belirlenmistir. Uretilen malzemenin fiziksel ozellikleri FT-IR, temas acisi ve yogunluk olcumleri ile belirlenmistir. En dusuk yogunluga sahip olan numune icin XRD, TG/DTG, N 2 adsorpsiyon/desorpsiyon ve SEM analizleri gerceklestirilerek malzeme karakterize edilmis ve termal yalitim ozelligi olan siva uretiminde degerlendirilmistir.

Yalcin Gorgulu T., Kipcak A.S., Dere Ozdemir O., Moroydor Derun E., Piskin S. (2014): Examination of the lemon effect on risk elements concentrations in herbal and fruit teas. Czech J. Food Sci., 32: 555–562. Fennel, mint (peppermint), and sage herbal teas and apple, lemon, and rosehip fruit teas were selected for the determi nation of the following risk elements contents: aluminium (Al), arsenic (As), barium (Ba), cadmium (Cd), nickel (Ni), lead (Pb), and antimony (Sb). Moreover, the effect of lemon on these elements contents was also examined. Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) was used for these experiments on selected teas (2 g of tea infused in 100 ml of water). The maximum changes of elements concentrations after the lemon addition were as follows: Al 1077 µg/l in lemon tea; Ba 12560 µg/l in rosehip tea; Cd 183 µg/l in sage tea; Ni 1136 µg/l in fennel tea; and Pb 238 µg/l in lemon tea. Both As and Sb were below the detection limits in pure tea and lemon-infused teas. This study indicated that after the lemon addition, rosehip tea had a hazard index (HI) value of 10827 × 10 –4 for 200 ml/day (2 cups/day), which represents a high risk for human health. If lemon is added to rosehip tea for consumption, 100 ml/day is recommended according to the calculated HI values.

In this study, the characterization and modification of waste magnesium chips (WMCs), which were produced by plastic molding in a gold manufacturing factory and are used as Mg-rich intermetallic composites in storing hydrogen, were discussed in detail. WMCs were analyzed using X-ray diffraction (XRD), X-ray fluorescence (XRF) spectroscopy, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analysis to characterize the materials’ structural properties. Mechanical milling, organic treatment, and inorganic salt addition were carried out to modify the WMCs’ surface to prepare Mg-rich intermetallic composites for storing hydrogen. The modified samples were analyzed using high-pressure volumetric analyses to calculate their hydrogen storage capacity. The authors conclude that modified WMC was promising as an Mg-rich intermetallic composite that was suitable for use in hydrogen storage with a 4.59 wt% capacity at 320 °C under a hydrogen pressure of 60 bar.

Effects of open-air sun drying and pre-treatment on drying characteristic of purslanes (Portulaca oleracea L.) were investigated. Drying times were determined as 31, 24 and 9 h for natural, salted and blanched, respectively. The higher “L” value and lower “−a/b” ratio values were obtained in natural dried purslane. The Aghbashlo et al. model gave a better fit to drying data.

In the present study, hydrogen desorption properties of magnesium hydride (MgH2) synthesized from modified waste magnesium chips (WMC) were investigated. MgH2 was synthesized by hydrogenation of modified waste magnesium at 320 °C for 90 min under a pressure of 6 × 106 Pa. The modified waste magnesium was prepared by mixing waste magnesium with tetrahydrofuran (THF) and NaCl additions, applying mechanical milling. Next, it was investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques in order to characterize its structural properties. Hydrogen desorption properties were determined by differential scanning calorimetry (DSC) under nitrogen atmosphere at different heating rates (5, 10, and 15 °C/min). Doyle and Kissenger non-isothermal kinetic models were applied to calculate energy (Ea) values, which were found equal to 254.68 kJ/mol and 255.88 kJ/mol, respectively.

In this study, ulexite, probertite found within sodium–calcium borates and borax, and tincalconite found within sodium borates retrieved from different regions in Turkey are evaluated for their neutron irradiation performances. Characterisations were performed using XRD, FT-IR, Raman spectroscopy. B2O3 contents were determined experimentally, structural water contents and surface morphologies were determined using DTA/TG and SEM. Neutron transmission values and total macroscopic cross-sections were determined using 239Pu–Be source moderated in a howitzer. Neutron transmission values from lowest to highest were found to be as follows: secondary ulexite (Kirka), tincalconite (Kirka), ulexite (Kestelek), ulexite (Kirka), borax (Kirka), probertite (Kestelek) and ulexite (Bigadic).

Consumption of tea is a popular tradition in Turkey. In this article, non essential and toxic element concentrations were determined in infusions and lemon added infusions in widely consumed Turkish teas (black, earl grey, and green tea). Element concentrations were found to be in the order of aluminum > nickel > barium in black and earl grey teas. In green tea, the order was changed to aluminum > nickel > lead > barium. The concentrations of arsenic and antimony were below the detection limit of the inductively coupled plasma optical emission spectrometry method employed. The addition of lemon increased aluminum, cadmium, and lead concentrations in all teas whereas nickel concentration increased in black and green tea but decreased in earl grey. The barium concentration was same at all tea samples. In comparison with the recommended daily allowance ratios, the amount of aluminum consumed is between 13.167–24.396% in males and 17.556–32.528% in females for people who consume 200 mL of teas daily. Other el...

The acrylamide-sodium acrylate hydrogel was synthesized by free radical polymerization of the method of solution polymerization. Dynamic swelling tests were conducted at 25, 40, and 60°C temperatures, in order to investigate the swelling properties of the synthesized hydrogel. The results have shown that swelling content and swelling rate of the hydrogel increase with increasing the swelling water temperature. The diffusivity values changed from1.81×10-7to2.97×10-7 m2 s−1over the temperature range. The activation energies were found as 3.56, 3.71, and 3.86 kJ mol−1at 25, 40, and 60°C, respectively. The experimental drying curves obtained were fitted to a three different models, namely, Peleg’s, first-order absorption kinetic, and exponential association equation models. All the models applied provided a good agreement with the experimental data with high values of the coefficient of determination (R2), the least values of the reduced chi-square (χ2), and root mean square error (RMSE). Comparing the determination of coefficient, reduced chi-square, and root mean square error values of three models, it was concluded that the exponential association equation model represents swelling characteristics better than the others.

Zinc borate (ZB) was synthesized using zinc oxide, boric acid synthesized from colemanite, and reference ZB as seed. The effects of reaction parameters such as reaction time, reactant ratio, and seed ratio on its yield were examined. Then, the effects of palm oil with solvents (isopropyl alcohol (IPA), ethanol, and methanol) added to the reaction on its hydrophobicity were explored. Reactions were carried out under determined reaction conditions with magnetically and mechanically stirred systems. The produced ZB was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and measurements of contact angle identified hydrophobicity. The results showed that hydrophobic ZB was successfully produced under determined reaction conditions. The change of process parameters influenced its yield and the usage of palm oil provided hydrophobicity.

Boron minerals, considered future essential materials, can be used as raw materials in the production of boron carbide. In this study, boron carbide, the hardest material after diamond and cubic boron nitride, is characterized and the neutron shielding behavior is investigated. The characterization and structural evaluation of the boron carbide sample was performed using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FT-IR) and Raman Spectroscopy. In addition, a neutron Howitzer was used to measure the neutron permeability of boron carbide samples of various thicknesses. The sample composed of 12.5 g of boron carbide powder and 3 g of Wax® had the lowest neutron permeability rate (62.1%). Pellet 3 had the smallest total macroscopic cross section of boron carbide particles, 0.722 ± 0.0071 cm−1.

The thermal behavior of tunellite has been examined by using thermal analysis data at different heating rates. Coats–Redfern, Horowitz–Metzger, Piloyan–Novikova, Doyle, and isoconversional Ozawa kinetic models have been used for the non-isothermal dehydration kinetic investigation of the mineral. The kinetic parameters are computed using the above-mentioned models for all dehydration stages. In addition, structural characterizations of tunellite are analyzed by using an X-ray diffractometer, an inductive coupled plasma-optical emission spectroscopy, Fourier transform infrared spectroscopy, and a scanning electron microscope.

In this paper, the kinetics and equilibrium of removing nickel from galvanic sludge leachate on nanocrystalline (14.6 nm) titania (TiO2) powders were studied for the first time. The pseudo-first-order, Natarajan and Khalaf, Bhattacharya and Venkobachar, the pseudo-second-order, Bangham’s equation, Elovich, and intraparticle diffusion kinetic models were applied in order to identify potential adsorption process mechanisms. The adsorption kinetic data were best represented by the second-order model (k 2 = 0.041 × 102 g mg−1 min−1). Thermodynamic parameters were also calculated to study the effect of temperature on the removal process. The positive Gibbs free energy (∆G°) and positive enthalpy change (∆H°) indicated the non-spontaneous and endothermic nature of the reaction, respectively. The equilibrium data for the adsorption of nickel on TiO2 nanoparticles were tested with two adsorption isotherm models, the Langmuir and Freundlich equations. The Langmuir model fits the adsorption isotherm data of nickel better than the Freundlich model. The maximum adsorption capacity obtained using the Langmuir isotherm model is 1.115 mg g−1 at pH 4. The dimensionless equilibrium parameter, R L, signifies a favorable adsorption of nickel on TiO2 nanoparticles adsorbent, and was found to be between 0.354 (0

The aim of this study was to synthesize zinc borate using zinc oxide, reference boric acid, and reference zinc borate (reference ZB) as the seed, and to investigate the effects of modifying agents and reaction parameters on the hydrophobicity and yield, respectively. The reaction parameters include reaction time (1–5 h), reactant ratio (H3BO3/ZnO by mass: 2–5), seed ratio (seed crystal/(H3BO3+ZnO) by mass: 0–2wt%), reaction temperature (50–120°C), cooling temperature (10–80°C), and stirring rate (400–700 r/min); the modifying agents involve propylene glycol (PG, 0–6wt%), kerosene (1wt%–6wt%), and oleic acid (OA, 1wt%–6wt%) with solvents (isopropyl alcohol (IPA), ethanol, and methanol). The results of reaction yield obtained from either magnetically or mechanically stirred systems were compared. Zinc borate produced was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and contact angle tests to identify the hydrophobicity. In conclusion, zinc borate is synthesized successfully under the optimized reaction conditions, and the different modifying agents with various solvents affect the hydrophobicity of zinc borate.

In this study, the solid state synthesis and reaction kinetics for Co/B as a catalytic/acidic accelerator for sodium borohydride (NaBH4) hydrolysis were investigated. The Co/B a catalytic/acidic accelerator was synthesized from cobalt(II) chloride hexahydride (CoCI2·6H2O) and boron oxide (B2O3) by a procedure based on solid state synthesis. Differential thermal analyses (DTA) were performed on mixtures of CoCI2·6H2O and B2O3 at four different heating rates (5, 10, 15 and 20 °C min−1) in order to determine the solid state reaction temperatures. Kissinger and Doyle kinetic models were applied to the reaction kinetics data for the solid state preparation. The ideal temperature for the solid-state synthesis of Co/B catalytic/acidic accelerator was 196 °C. Additionally, the catalytic behavior of solid state synthesized Co/B as an catalytic/acidic accelerator for NaBH4 hydrolysis was investigated. The hydrolysis reactions were performed at temperatures of 22, 40, and 60 °C and the experimental data were fitted to zeroth, first, and second order kinetic models. The maximum hydrogen generation rate was 5,470 ml H2 min−1 g−1 cat and Ea was only 48.07 kJ mol−1.

Sepiolite and bentonite have a wide range of industrial applications based on their physicochemical properties such as surface area, thermal behavior, chemical composition, and mineralogic composition. The thermal behavior and kinetics of naturally occurring sepiolite and bentonite were determined in order to give an idea about the potential use of naturally occurring clay minerals in possible applications. Naturally occurring sepiolite and bentonite samples were heated to the temperature that was achieved at the end of the dehydroxylation process. Mineralogic and thermal characteristics of raw and heat treated samples were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, and nitrogen adsorption/desorption analyses. Changes in the structure following heat treatment were used for the evaluation of the dehydroxylation properties of the samples. The dehydroxylation properties of the minerals are strongly affected by the crystal structure. Kinetic analyses, which were related to the dehydroxylation of naturally occurring sepiolite and bentonite, were conducted using dynamic thermogravimetry/derivative thermogravimetry analysis under nitrogen atmosphere. Flynn–Wall–Ozawa, Kissenger–Akahira–Sunose, and Friedman isoconversional methods were used to determine the activation energies of the dehydroxylation reactions of the samples. The results indicate that the activation energy of naturally occurring sepiolite showed a little variation at a particular conversion rate (0.3–0.7), while the activation energy of naturally occurring bentonite showed a significant variation within the range of variation of the conversion rate. The present study shows that the dehydroxylation reactions of naturally occurring sepiolite and bentonite were single mechanism reaction and complex mechanism reaction, respectively.

Mesoporous silica MCM-41 was prepared by classical and ultrasound methods as an adsorbent for the removal of Sr2+ from aqueous solution. The physical properties of the synthesized materials were investigated by X-ray diffraction and Brunauer-Emmett-Teller analysis. The results showed that MCM-41 prepared by the classical method had higher specific surface area and pore volume than those prepared by the ultrasound method. Therefore, it was selected as an adsorbent for the investigation of adsorption isotherms and kinetics. Adsorption of Sr2+ to MCM-41 was strongly dependent on pH values. Three two-parameter (Langmuir, Freundlich, and Temkin) and two three-parameter (Redlich–Peterson and Koble–Corrigan) adsorption isotherms were employed to model the equilibrium data of Sr2+ on the mesoporous adsorbent. The results indicated that the adsorption isotherm data fitted better to the Freundlich isotherm than to the Langmuir, Temkin, Redlich–Peterson, and Koble–Corrigan isotherms. The experimental data was described very well by the pseudo-second-order kinetic model.

The study presented in this manuscript focuses on the manufacturing of roof tiles bearing a mixture of tile waste and coal fly ash. A roof tile sample at a different composition was prepared to attain consistence in quality. The conversion factors were described to be able to convert the laboratory results for firing strength and water absorption into the industrial operating conditions. It was determined that the replacement mixture of the tile waste as well as the Tunçbilek fly ash together with the Muttalip clay as the raw material allowed the manufacturing of good quality roof tiles. Seyitömer fly ash was not suitable for use as secondary raw material due to the presence of tile waste with higher SO3 and CaO contents and lower MgO content. In addition to this, maximum 5 % Tunçbilek fly ash samples in the composition of roof tiles provided favorable physical and mechanical characteristics of the commercial product.

The aim of the current study is to obtain the thermal behavior and kinetic analyses of the removal of surfactant from MCM-41 synthesized from tailings slurry at different heating rates. X-ray diffraction and thermogravimetric analyses were carried out to determine the characterization of the synthesized samples. Kissinger–Akahira–Sunose and Friedman isoconversional kinetic methods were applied for the purpose of determining the kinetic analysis parameters of the decomposition of surfactant from the mesoporous molecular sieves MCM-41 under non-isothermal conditions. For the comparison of these results, MCM-41 was synthesized from a pure silica source. The thermal behaviors of MCM-41 synthesized from tailings slurry do not differ from samples synthesized from pure silica during the decomposition reactions. The kinetic analysis’ results indicate that the decomposition reactions of the synthesized MCM-41 samples had complex reaction mechanisms. © 2017, Akadémiai Kiadó, Budapest, Hungary.

In this study, the synthesis of barium metaborate powder (BaB2O4) was carried out by ultrasound-assisted precipitation using different borate solutions. Different solutions such as borax (Na2B4O7, BD), boric acid (H3BO3, BA), and sodium metaborate (NaBO2, SMB) were used in the synthesis and an ultrasonic immersion horn probe was used as the major source of ultrasound. The effect of reaction temperature and time, pH, and crystallization time on the BaB2O4 yield (%) was investigated. The ultrasound-assisted synthesis up to 90 % yield could be achieved using a 0.2 M BD solution at 80 °C, reacting for 5 min at pH 13 followed by 2 h of crystallization. Following crystallization, the obtained powder was heated up to 140, 250, 650, and 750 °C for 2.5 h, and it was shown that β-BaB2O4 nanometric powders were obtained after the 750 °C heat treatment.

In the present study, a novel microwave assisted method has been developed for sodium metaborate dihydrate (NaBO 2 ·2H 2 O) synthesis. Anhydrous NaBO 2 , a derivative of borax, is an industrially and technologically important boron compound used as a raw material for the thermochemical production of sodium borohydride (NaBH 4 ). The effects of different microwave treatment conditions such as microwave power (90, 270 and 360 W) and irradiation time (1, 2, and 5 min) on the synthesis of NaBO 2 ·2H 2 O were examined. After microwave irradiation at 270 W for 1 min, NaBO 2 crystals with 2 molar equivalents of water were formed. Anhydrous NaBO 2 was obtained following incubation at 400 °C for 33 min under calcination conditions. Then the resulting anhydrous NaBO 2 powder was reacted with MgH 2 under 60 bar hydrogen atmosphere at 470 °C, leading to successful production of NaBH 4 with 93% yield.

hermal degradation characteristics of Tetra Pak panel boards (TPPB) can be useful to improve usage of such panels as an alternative to wood-based products such as plywood, fiberboard, and particleboard. In the study, samples from the TPBBs manufactured from waste Tetra Pak packages (WTPP) were heated in a nitrogen atmosphere at different heating rates (10, 15 and 20 °C/min) using a thermal analysis system. The Coats-Redfern kinetic model was applied to calculate kinetic parameters. The degradation rate equations were then established. In addition, the kinetic compensation effect (KCE) was used to correlate the pre-exponential factor (k o ) with activation energy (E a ) and the existence of the KCE was accepted. TG-FT/IR analyses were applied to the TPPB degradation and then the FT-IR stack plot was used to analyze gas products (CO2, CH4, HCOOH, and CH3OH). Infrared vibrational frequencies and the micro, crystal structure of the TPPBs were investigated by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and X-Ray diffraction analysis (XRD), respectively.