scholarly journals KATALIS KARBON YANG DIBUAT DENGAN METODE HUMMERS TERMODIFIKASI UNTUK ASETILASI GLISEROL

2021 ◽  
Vol 6 (2) ◽  
pp. 95
Author(s):  
Nur Hidayati ◽  
Wahib Khoiruddin ◽  
Isnadiah Endang Mastuti ◽  
Wahyu Devi Satna Pambudi

Gliserol adalah produk samping yang dihasilkan dari proses pembuatan biodiesel. Karena peningkatan produksi biodiesel, utilisasi gliserol yang melimpah menjadi asetin berpeluang dilakukan karena manfaat asetin sebagai sumber bahan baku untuk material lainnya yang bernilai lebih. Penelitian ini bertujuan untuk membuat katalis grafena oksida dari multi-walled carbon nanotubes (MWCNT) dengan menggunakan metode hummers termodifikasi. Karakterisasi katalis GO dilakukan dengan menggunakan uji X-Rays Diffraction (XRD) dan Scanning Electron Microscope-Energi Dispersive X-ray (SEM-EDX). Aktivitas katalitik pada asetilasi gliserol menunjukkan konversi yang tinggi mencapai 94% pada suhu 110°C dalam 2 jam reaksi dengan menggunakan katalis 3% berat. Kata kunci: Asetilasi, Gliserol, Grafena Oksida, Metode Hummers Termodifikasi AbstractGlycerol is a by-product of biodiesel production. Due to the increase in biodiesel production, the utilization of abundant glycerol into acetin has the opportunity to be carried out because of the benefits of acetin as a source of raw material for other materials of higher value. This study aims to prepare graphene oxide catalysts from multi-walled carbon nanotubes (MWCNT) using the modified Hummers method. The characterizations of GO catalyst were assessed using X-Rays Diffraction (XRD) and Scanning Electron Microscope-Energi Dispersive X-ray (SEM-EDX). The catalytic activity of glycerol acetylation showed a high conversion reaching 94% at 110°C in 2 hours of reaction using a 3% by weight catalyst.

2019 ◽  
Vol 30 (8) ◽  
pp. 1216-1224 ◽  
Author(s):  
Mohammad Charara ◽  
Mohammad Abshirini ◽  
Mrinal C Saha ◽  
M Cengiz Altan ◽  
Yingtao Liu

This article presents three-dimensional printed and highly sensitive polydimethylsiloxane/multi-walled carbon nanotube sensors for compressive strain and pressure measurements. An electrically conductive polydimethylsiloxane/multi-walled carbon nanotube nanocomposite is developed to three-dimensional print compression sensors in a freestanding and layer-by-layer manner. The dispersion of multi-walled carbon nanotubes in polydimethylsiloxane allows the uncured nanocomposite to stand freely without any support throughout the printing process. The cross section of the compression sensors is examined under scanning electron microscope to identify the microstructure of nanocomposites, revealing good dispersion of multi-walled carbon nanotubes within the polydimethylsiloxane matrix. The sensor’s sensitivity was characterized under cyclic compression loading at various max strains, showing an especially high sensitivity at lower strains. The sensing capability of the three-dimensional printed nanocomposites shows minimum variation at various applied strain rates, indicating its versatile potential in a wide range of applications. Cyclic tests under compressive loading for over 8 h demonstrate that the long-term sensing performance is consistent. Finally, in situ micromechanical compressive tests under scanning electron microscope validated the sensor’s piezoresistive mechanism, showing the rearrangement, reorientation, and bending of the multi-walled carbon nanotubes under compressive loads, were the main reasons that lead to the piezoresistive sensing capabilities in the three-dimensional printed nanocomposites.


Author(s):  
W. Brünger

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.


Author(s):  
Marc H. Peeters ◽  
Max T. Otten

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.


2012 ◽  
Vol 620 ◽  
pp. 384-388
Author(s):  
Sharifah Aishah Syed Salim ◽  
Julie Juliewatty Mohamed ◽  
Zainal Arifin Ahmad ◽  
Zainal Arifin Ahmad

Numerous methods have been used to produce high purity TiC. There is no previous study has been reported on the formation using single elemental powders of Titanium (Ti) and Carbon (C) with addition Nickel (Ni) by tungsten inert gas (TIG) weld method. In this work, TiC was synthesized via TIG method by arc melting elemental powder mixture of Ti and C at ~5 second (s) and 80 ampere (A). The effect Ni contents on TiC formation was investigated. The mixed raw material was ball milled for 24 hours followed by synthesis via TIG method. The arced samples were characterized by X-ray diffraction (XRD) and Scanning electron microscope (SEM). It was revealed, that small amount of Ni additive to the metal powder allows the production of dense and tough TiC.


2018 ◽  
Vol 163 ◽  
pp. 05008
Author(s):  
Anna Skawińska

This paper presents the results of the studies carried out in the model systems and concerning the tobermorite synthesis with an addition of metahalloysite. Quartz sand and quicklime were the main raw material constituents. The mixtures in the form of slurries underwent hydrothermal treatment with an addition of metahalloysite (5%, 10%, 15%, 20% and 30%) for 4 hours and 12 hours. The resultant composites were analysed for their phase composition using X-ray powder diffraction. The microstructure was examined using the Scanning Electron Microscope. Tobermorite was the principle reaction product. When 30% metahalloysite was added to the mixture containing CaO and SiO2, the formation of katoite was found.


2018 ◽  
Vol 7 (3) ◽  
pp. 333-337
Author(s):  
Esther Lorrayne Machado Pereira ◽  
Adriana de Souza Medeiros Batista ◽  
Fabíola A. S. Ribeiro ◽  
Adelina P. Soares ◽  
Arno H. Oliveira ◽  
...  

2014 ◽  
Vol 926-930 ◽  
pp. 258-261
Author(s):  
Jing Heng Deng ◽  
Kan Ping Yu ◽  
Jian Guo Xie

Hierarchical nanostructure Fe3O4/multi-walled carbon nanotubes (Fe3O4/MWCNTs) were prepared by solvothermal process using acid treated MWCNTs and iron acetylacetonate in ethylene glycol as reduction reagent. The materials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET). The results showed that petal-like hierarchical Fe3O4 grew on MWCNTs and the Fe3O4 nanoparticles had diameters in the range of 55-110 nm. It was a facile approach to grow hierarchical nanoFe3O4.


2013 ◽  
Vol 1493 ◽  
pp. 139-144 ◽  
Author(s):  
Punya A. Basnayaka ◽  
Pedro Villalba ◽  
Manoj K. Ram ◽  
Lee Stefanakos ◽  
Ashok Kumar

AbstractIn the present study, we have studied photoelectrochemical properties of poly(3-octathiophene) (P3OT), blending with multi-wall carbon nanotubes (MWCNTs). P3OT blended with MWCNTs was characterized using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Raman spectroscope, and Cyclic Voltammetry (CV) techniques, respectively. The photoelectrochemical current of the MWCNs-P3OT based cell under illumination was investigated by applying a voltage. The blend consisting of 10% MWCNTs in P3OT gave the promising photocurrent in 0.2 M tetra-butyl-ammonium-tetrafluoroborate (TBATFB), electrolyte. Experimental results indicate that photocurrent obtained from MWCNT-P3OT was three times higher than simple P3OT-based conducting polymer. The electrochemical responses of MWCNT-P3OT films in different electrolytes such as 0.2M TBATFB, 0.2 M LiClO4, 1 M H2SO4 and 0.2 M LiBF6 were investigated for comparative photocurrent properties of the photoelectrochemical cell.


Author(s):  
Dewi Elok Rahmawati ◽  
Lilik Miftahul Khoiroh ◽  
Rachmawati Ningsih ◽  
Febi Yusniyanti ◽  
Wariatus Solawati ◽  
...  

<p class="02abstracttext"><span lang="PT-BR">Iron lathe waste powder has the potential as a raw material in the synthesis of hematite pigments. Hematite pigments have many advantages, one of which is anti-swelling properties that can maintain the dimensions of wood. Hematite pigment synthesis was carried out using the precipitation-sonication method. The precipitation stage uses an ammonium hydroxide solution as a precipitating agent. Stages of sonication using the PEG-6000 template were performed at different times were 30, 45, and 90 minutes then calcined at 750 ° C for 3 hours. The samples were characterized by X-ray diffraction (XRD), color reader, and scanning electron microscope-energy dispersive <br /> X-Ray (SEM-EDX). The result confirmed that a ferrihydrite phase obtained after the precipitation process and transform into hematite after the calcination process with the highest degree of crystallinity for 90-minute sonication. From a color reader, the brightness and redness degrees decrease with increasing time. Scanning electron microscope results illustrated that the morphology was not uniform with the particle size getting smaller with increasing sonication time. The EDX results show that hematite pigments still contain impurities such as carbon. The swelling test indicated that the highest stability in hematite-pigmented wood increased as increasing in the weight of pigment.</span></p>


Sign in / Sign up

Export Citation Format

Share Document