Etanolün su buharı ile reformlanması ile hidrojen üretimi için yeni çift metalli mezo-gözenekli katalizörler.

Hydrogen is considered as an alternative clean energy source due to the depletion of fossil fuels and related environmental problems. Steam reforming of bio-ethanol, has excellent potential for hydrogen production, with CO2 neutrality. Ni, Pd and Pt are the most active metals for steam reforming of ethanol. Improving catalytic activity of supported Ni catalyst by incorporating small amount of Pd or Pt is a successful method for increasing activity and stability of the catalyst. Development of active and stable catalysts with low coke formation and high hydrogen yield attracted major attention of researchers in recent decades. MCM-41 supported bimetallic mesoporous catalytic materials containing well dispersed Ni and Pd nanoballs were synthesized following an impregnation procedure. TEM images and XRD analysis of these materials indicated the formation of nickel and palladium nanoballs of 15-25 nm and 5-8 nm respectively, within the synthesized materials. These materials have quite narrow pore-size distributions in the range of 1-5 nm. In the calcined materials, nickel was in Ni+3 and Ni+2 states, however in the reduced sample most of the nickel was in Nio state, together with some NiO. Formation of NiOx crystals takes place after the calcination step. Impregnation of palladium into Ni/MCM-41 caused a decrease in the reduction temperature of NiO for about 50oC. Activity of the catalytic materials were tested in the reaction of steam reforming of ethanol.all the catalysts showed high conversion and quite high hydrogen yield over 400 oC. PdNi impregnated MCM-41 supported catalysts showed higher conversion of ethanol but lower hydrogen yield than Ni impregnated catalysts due to methane formation in the case of Pd incorporation. However, MCM-41 does not show enough hydrothermal stability for steam reforming of ethanol reaction. SBA-15 has very similar physical properties of MCM-41 with larger pores and high hydrothermal stability. Ceria also has widespread applications in catalysis area with its excellent oxygen buffering capacity. It can be used as catalyst support and also an improving agent for silica supports. Mesoporous silica SBA-15 with ordered pore structure was synthesized following a hydrothermal procedure and then bimetallic Ni-Ce and Pd-Ni-Ce incorporated mesoporous silica catalysts were prepared and tested in steam reforming of ethanol. On the other hand, ceria enriched silica structures i.e cerium/silicate composites were also synthesized. However the syntheses were unsuccessful due to the thermal sintering of ceria. Addition of ceria to the support structure decreased coke formation significantly.. According to the thermal gravimetric analysis studies conducted after ethanol steam reformin reaction at 600 oC, coke formation with Ni-SBA-15 (Ni/Si=0.10) catalyst was 40% and it was 10% with NiCe-SBA-15 (Ni/Si=0.10, Ce/Si=0.50) Activity test results obtained with Ni incorporated silica catalysts in steam reforming of ethanol gave high hydrogen yield over 4 (max. 6) and complete conversion of ethanol at 600 oC. SBA-15 found to be more stable catalyst than MCM-41 in the steam reforming of ethanol reaction. The highest hydrogen yield values were achieved by AlMCM-41 supported Ni-Ce impregnated catalysts. Aluminum in the slica matrix (3% wt.) increased the catalytic activity significantly, by giving acidic properties to the catalyst. Simultaneous and consecutive Ni and Ce impregnation were also examined. AlMCM-41 supported, consecutively Ce and Ni impregnated catalysts with Ce/Si and Ni.Si molar ratio sof 0.10, showed very high catalytic activity (5.8 at the beginning). AlMCM-41 supported catalyst were less stable because of high activity and consequently coke formation.Ph.D. - Doctoral Progra

Pd-MCM-tip mezo-gözenekli nanokompozit malzemelerin sentez ve karakterizasyonu

Noble metal incorporated MCM-41 based nanostructured mesoporous materials have attracted the attention of material researchers in recent years. Sorption characteristics of MCM materials can be improved by surface modification techniques. Besides surface modification, metal nanoparticles can also be produced within the pores of mesoporous materials. MCM-41 can act as host for several metal nanoparticles such as palladium. The present study is focused on the synthesis of Pd-MCM-41 nanocomposite catalytic materials by using different direct synthesis procedures, as well as an impregnation method. Impregnated samples were used to synthesize Pd nanoparticles inside the pores of MCM-41. In the direct hydrothermal synthesis of Pd-MCM-41, incorporation of the Pd metal was achieved by adding PdCl2, K2PdCl4 and Pd(NH3)4(NO2)3 solutions into the synthesis mixture. Syntheses were performed in acidic and basic routes. Hydrothermal synthesis was carried out in an autoclave at 120 oC. The solid product was filtered, washed, dried, calcined at 550 oC in a stream of dry air and reduced in a stream of hydrogen at 200 oC. In the case of impregnation, PdCl2 solution was added to a suspension of MCM-41. The product was evaporated to dryness, dried under vacuum and reduced with H2 gas at 200 oC. Physical and chemical properties and surface morphology of Pd-MCM-41 nanomaterials were characterized by using XRD, XPS, EDS, BET, SEM, TEM and TPR techniques. Very high Pd/Si ratios, as high as 0.45 and 0.18 were obtained in the mesoporous materials produced by the basic and acidic direct synthesis routes, respectively. The BET surface areas of these materials were found as 999 m2/g and 694 m2/g, respectively. These results showed that the basic direct synthesis procedure was highly successful for the incorporation of Pd into the mesoporous Si structure. In addition, EDS analysis of the Pd-MCM-41M.S. - Master of Scienc

Biyokütle türevlerinden hidrojen üretimi için yeni katalizörler

TÜBİTAK MAG Proje01.09.200

Don't let our operating theatre to be desert

PURPOSE OF THE STUDY The purpose of this study is to reveal the waste of water by medical staff hand scrubbing preoperatively in the operation theatre, draw attention to the water consumption with small precautions. The study compares motion -sensitive sensor tap with an uncensored classic tap, to assess the difference of water consumption during hand scrubbing. MATERIAL AND METHODS The presented study compared two groups; hand scrubbing with sensory tap was enrolled as group A and classic tap with running water was enrolled as group B. Three participants were included in each group. Operation faucets with a motion-sensitive sensor and timekeeper were used in group A. Running water from a tap in 10 seconds was measured with the help of a measuring cup. The water amount after 3 minutes of washing was also measured. The difference between the two obtained data was compared. The obtained data were also multiplied to the global surgical data. RESULTS Measurements were performed with a measuring cup and it was measured that 1,250 ml of water is running from faucets in 10 seconds. In group A, faucets were open for 23 seconds whereas in group B faucets were open for 180 seconds. In group A, water utilization was 2,875 ml per person (8,625 ml for three), in group B was the water utilization of 22,500 ml per person (67,500 ml for three). Regarding this data for a single operation, the consumption difference between the two groups was measured as 58,875 ml. The total count of major surgery worldwide per year is reported to 321,500,000. When this number is multiplied with the obtained data, it is calculated that the total amount of water to be saved between the two groups is 18,928,313 m(3). That is equal to one year of water consumption of a city with 125,000 inhabitants. CONCLUSIONS In conclusion, as healthcare professionals, it is possible to save enough water as a medium-sized city by changing our handwashing habits in the operation rooms. As a result, water-conserving systems and hand scrubbing education can be very effective in using the natural resources economically and protecting these resources

Ankara Polatlı mevkiinde bulunan Yassıhöyük Tümülüsü, Gordion kalıntıları ve sit alanının bölge halkına etkileri

Ankara : İhsan Doğramacı Bilkent Üniversitesi İktisadi, İdari ve Sosyal Bilimler Fakültesi, Tarih Bölümü, 2015This work is a student project of the The Department of History, Faculty of Economics, Administrative and Social Sciences, İhsan Doğramacı Bilkent University.by Aslan, Mustafa Çağatay

Determination of the Most Commonly Recognized and Used Keratin Based Luxury Fibers

There is a group of animal fibers known as luxury fibers. These are mohair, cashmere, camel hair, lama, alpaca, vicuna, guanaco, angora, yak, and quivit. In this study, the effects of demographical variables such as gender, education, age, sector, and income on the recognition and usage of luxury fibers in Thrace Region of Turkey were investigated. In order to analyze the obtained data, crosstabulation and chi-square statistical methods are used. According to the experimental results it can be said that the most commonly known and used luxury fibers are cashmere, mohair, and angora. The most important (37.6%) reason for participants to use luxury fibers is their warm feeling. On the other hand the most important (approx. 30%) reason for participants not to use them is that they do not have sufficient information about these fibers. It was determined that the most commonly (37.8%) used textile product made of luxury fibers is outerwear. Furthermore, it was found out that approximately 75% of participants accept paying more for garment containing luxury fibers because of their high quality.WOS:0003440623000072-s2.0-8490868884

MCM-41 supported PdNi catalysts for dry reforming of methane

A series of bimetallic PdNi catalysts supported on mesoporous MCM-41 with different Ni content (Ni/Si ratio of 0.2-0.4) was synthesized. The effect of Pd addition to Ni-containing catalysts as well as the effect of the Ni content on the surface and catalytic properties of the catalysts was studied. The samples were characterized using various techniques, such as energy-dispersive X-ray spectroscopy, N(2) adsorption-desorption isotherms, X-ray diffraction, thermogravimetric and differential analyses, X-ray photoelectron spectroscopy, high resolution transmission electron microscopy and temperature-programmed reduction. Reforming of methane with carbon dioxide was used as a test reaction. The results indicated that the addition of a small amount of Pd (0.5%) to Ni-containing catalysts leads to formation of small nano-sized, easy reducible NiO particles. Agglomeration of NO as well as of metallic nickel phase over PdNi samples increased with increasing the Ni content. Formation of filamentous carbon over surface of spent monometallic Ni and bimetallic PdNi catalyst was observed. In spite of filamentous carbon deposition, the catalytic activity and stability of bimetallic PdNi catalysts are higher than those of monometaillic Ni one. Within bimetallic system, the PdNi catalyst with Ni/Si ratio of 0.3 revealed the best performance and stability caused by presence of small nickel particles well dispersed on the catalyst surface

Recovery of Cr(VI) by using a novel calix[4]arene polymeric membrane with modified graphene quantum dots

Abstract: In this report, the recovery of Cr(VI) from chrome plating water by using a novel calix[4]arene-functionalized graphene quantum dots (GQDs) involved polymer inclusion membrane was investigated. The polymeric membrane supported by GQDs was characterized by using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM and AFM results clearly show that there are much larger visible pores on the membrane surface after modification of polymer inclusion membrane with GQDs and the micropores in the membrane surface were vanished and performed with GQDs after modification of membrane. The transport efficiency of chromium was found to be 97.23% through the modified membrane from 0.1 M HCl as donor phase to pH 5 as an acceptor phase. The system is available for long-term usage. The highly selective and mechanical strength of membrane is developed by adding GQDs. Modified membrane exhibits significant stability and selectivity, and the system is used for the real samples. Graphical Abstract: [Figure not available: see fulltext.]. © 2017, Islamic Azad University (IAU)