scholarly journals Preparasi Katalis MgO/C dari Pirolisis Polimer Berbasis Magnesium Salisilat dan Aplikasinya untuk Reaksi Transesterifikasi

2021 ◽  
Vol 15 (1) ◽  
pp. 84
Author(s):  
Imam Prasetyo ◽  
Dwiana Ayu Kiranti Nur’aeni ◽  
Pandu Timur Bhaskara
Keyword(s):  
Electron Microscopy ◽  
Magnesium Oxide ◽  
Phenolic Resin ◽  
Solid Base ◽  
Base Catalyst ◽  
X Ray Diffraction ◽  
Solid Base Catalyst ◽  
Phenolic Resins ◽  
X Ray ◽  
Scanning Electron

The objective of the study is to produce carbon-based magnesium oxide (MgO) solid base catalyst by pyrolysis of phenolic resin and to examine the material effectiveness as a catalyst for transesterification reaction. The phenolic resins were prepared by polymerization process of phenol, derivative salicylic acid (magnesium salicylate), and formaldehyde aqueous solution under acidic condition using H2SO4 as catalyst. The molar ratio of magnesium salicylate:phenol:formaldehyde was 0.33:0.67:2.80. Carbon-based magnesium oxide solid base catalyst (MgO/C) was produced from phenolic resins via physical activation process using steam at 850°C.  Material was characterized using N2-sorption analysis, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Pyrolysis process for carbon formation resulted in 75% burn-off. The specific surface area of catalyst was 494 m2/g and the presence of MgO was confirmed by XRD diffraction pattern (2θ position of 36-43°, 61-63°, dan 74-78° according to JCPDS No.89-7746) and SEM image. Characteristic comparison of MgO/C with carbon produced from phenol formaldehyde resin (without magnesium salicylate) corroborate the finding that MgO/C was achieved. The catalyst was tested for transesterification reaction between palm oil and methanol. Conversion of 28.3% was achieved at temperature of 65 °C, reactant ratio of methanol: palm oil = 6:1 and reaction time of 2.5 hours. The activation energy of 6,444 cal/mol was obtained when evaluated in the range of 55-65 °C reaction temperature.Keywords: biodiesel; catalyst; magnesium oxide; phenolic resin; porous carbonA B S T R A KTujuan penelitian ini adalah membuat katalis magnesium oksida (MgO) yang teremban dalam karbon hasil dari proses pirolisis resin fenolik dan menguji efektivitasnya sebagai katalis reaksi transesterifikasi. Resin fenolik diperoleh melalui proses polimerisasi fenol, turunan asam salisilat (magnesium salisilat), dan formaldehid dalam kondisi asam menggunakan H2SO4 sebagai katalis. Rasio mol dari magnesium salisilat:fenol:formaldehid adalah 0,33:0,67:2,80. Katalis magnesium oksida teremban pada karbon (MgO/C) diperoleh dari pirolisis resin fenolik menggunakan steam pada suhu 850°C. Material dikarakterisasi dengan N2 adsorpsi-desorpsi isotherm, X-ray diffraction (XRD) dan scanning electron microscopy (SEM). Pirolisis untuk menghasilkan karbon memiliki burn-off sekitar 75%. Hasil penelitian menunjukkan bahwa katalis MgO/C memiliki luas permukaan sekitar 494 m2/g dan keberadaan MgO dikonfirmasi dari hasil pola difraksi XRD (posisi 2θ antara 36-43°, 61-63°, dan 74-78° sesuai dengan standar JCPDS No.89-7746) dan gambar SEM. Pembandingan karakteristik MgO/C dengan karbon hasil polimer fenol formaldehid (tanpa magnesium salisilat) memperkuat kesimpulan bahwa MgO/C dapat diperoleh. Katalis yang diperoleh digunakan sebagai katalis transesterifikasi antara minyak kelapa sawit dengan metanol. Konversi reaksi sebesar 28,3% didapatkan pada suhu 65 °C dan rasio reaktan metanol:minyak kelapa sawit = 6:1 dan waktu reaksi 2,5 jam. Energi aktivasi sebesar 6.444 kal/mol diperoleh pada rentang suhu reaksi 55-65 °C.Kata kunci: biodiesel; karbon berpori; katalis; magnesium oksida; resin fenolik

scholarly journals Growth of Carbon Nanofibers in Phenolic Resin for Carbon-Contained Refractory Using Different Catalysts

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Jun Yu ◽  
Huizhong Zhao ◽  
Han Zhang ◽  
Jingjie Li ◽  
Xiongfeng Ding
Keyword(s):  
Carbon Nanofibers ◽  
Phenolic Resin ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
Phenolic Resins ◽  
X Ray ◽  
Cracking Process ◽  
Carbon Losses ◽  
Scanning Electron

Various phenolic resins modified with carbon nanofibers were prepared using Fe(NO3)3, Co(NO3)2, and Ni(NO3)3 as catalyst, respectively. The influences of different catalysts on the phase, microstructure evolution, and oxidation resistance of the modified phenolic resin were investigated by X-ray diffraction analysis, field-emission scanning electron microscopy, and thermal gravimetric analysis. The results showed that, compared with a single catalyst, the mixed catalysts (Co(NO3)2 : Fe(NO3)3 = 1 : 1) promoted the growth of the carbon nanofibers, which have the higher crystallinity, homogeneous dispersion, and nonagglomeration. These carbon nanofibers can effectively reduce carbon losses, increase char yield, and fill the holes in the thermal cracking process of phenolic resins.

Effect of Synthesis Method on the Nanostructures of Magnesium Oxide (MgO) and their Band Gap Energies

2012 ◽  
Vol 545 ◽  
pp. 153-156 ◽  
Author(s):  
Nor Fadilah Chayed ◽  
Nurhanna Badar ◽  
Rusdi Roshidah ◽  
Norashikin Kamarudin ◽  
Norlida Kamarulzaman
Keyword(s):  
Electron Microscopy ◽  
Band Gap ◽  
Magnesium Oxide ◽  
Sol Gel ◽  
Synthesis Method ◽  
Nir Spectroscopy ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Magnesium oxide (MgO) is a metal oxide which has many applications in industry and can be synthesized by many different synthesis methods. In this study, MgO was synthesized by using two different methods which were sol-gel and solid-state reaction methods. Both samples were annealed at 800 oC for 24 hours and characterized by using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The band gap energies for both samples were determined by using UV-Vis NIR Spectroscopy. The band gap values of the samples are evaluated from the data. It was found that the band gap energies of the MgO using different synthesis route were not the same.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

The Effect of the Microstructure of Diffusion Barriers on the Palladium Activation for Electroless Copper Deposition

2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park
Keyword(s):  
Electron Microscopy ◽  
Diffusion Barriers ◽  
Copper Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Electroless Copper ◽  
Sheet Resistance Measurement ◽  
Scanning Electron

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

Structural Characterization of Gallbladder Stones Using Energy Dispersive X-ray Spectroscopy and X-ray Diffraction

2018 ◽  
Vol 21 (7) ◽  
pp. 495-500 ◽  
Author(s):  
Hassan A. Almarshad ◽  
Sayed M. Badawy ◽  
Abdalkarem F. Alsharari
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Energy Dispersive ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Major Health Problem ◽  
X Ray ◽  
Gallbladder Stones ◽  
Pure Cholesterol ◽  
Scanning Electron

Aim and Objective: Formation of the gallbladder stones is a common disease and a major health problem. The present study aimed to identify the structures of the most common types of gallbladder stones using X-ray spectroscopic techniques, which provide information about the process of stone formation. Material and Method: Phase and elemental compositions of pure cholesterol and mixed gallstones removed from gallbladders of patients were studied using energy-dispersive X-ray spectroscopy combined with scanning electron microscopy analysis and X-ray diffraction. Results: The crystal structures of gallstones which coincide with standard patterns were confirmed by X-ray diffraction. Plate-like cholesterol crystals with laminar shaped and thin layered structures were clearly observed for gallstone of pure cholesterol by scanning electron microscopy; it also revealed different morphologies from mixed cholesterol stones. Elemental analysis of pure cholesterol and mixed gallstones using energy-dispersive X-ray spectroscopy confirmed the different formation processes of the different types of gallstones. Conclusion: The method of fast and reliable X-ray spectroscopic techniques has numerous advantages over the traditional chemical analysis and other analytical techniques. The results also revealed that the X-ray spectroscopy technique is a promising technique that can aid in understanding the pathogenesis of gallstone disease.

scholarly journals Preliminary Study of the Targeted Cleaning of an Artificial Gypsum Layer on White Marble

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 37
Author(s):  
Yan Liu ◽  
Taoling Dong ◽  
Kun Zhang ◽  
Fuwei Yang ◽  
Liqin Wang
Keyword(s):  
Electron Microscopy ◽  
Barium Carbonate ◽  
Color Difference ◽  
X Ray Diffraction ◽  
White Marble ◽  
Capillary Suction ◽  
Sulfate Ions ◽  
X Ray ◽  
Preliminary Study ◽  
Scanning Electron

Targeting cleaning of the artificial gypsum layer on white marble was studied. It was conducted by means of the specific depletion of the calcium and sulfate ions by the barium carbonate scavenger, which led to the continuous dissolution and clearance of gypsum layer. The cleaning effect was evaluated by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), capillary suction, and color difference measurement. By this method, only the gypsum layer was cleared away and the carbonate substrate of marble was left intact at the same time. This method will be highly useful for the conservation of marble relics from surface weathering.

scholarly journals Analytical study of Buddha sculptures in Jingyin temple of Taiyuan, China

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaojian Bai ◽  
Chen Jia ◽  
Zhigen Chen ◽  
Yuxuan Gong ◽  
Huwei Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Analytical Study ◽  
Energy Dispersive Spectrometry ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Ancient China ◽  
X Ray ◽  
Unique Style ◽  
Scanning Electron

AbstractWith exquisite design and unique style, the painted sculptures of Tutang Buddha and two attendants Buddha in Jingyin Temple are precious cultural heritages of China. The sculpture of Tutang Buddha, which was carved from a mound and painted by ancient craftsmen, was rarely found in ancient China. However, due to natural and human factors, the sculptures were severely damaged. Obviously, they require urgent and appropriate protection and restoration. In this study, samples taken from the sculptures were analysed through multiple analytical techniques, including scanning electron microscopy with energy dispersive spectrometry (SEM–EDS), Raman spectroscopy, X-ray diffraction (XRD), optical microscopy (OM) and granulometry. The analysis results enable us to infer the techniques used by the craftsmen in making the sculptures and provide a reliable evidence for the conservation and future protection of these and similar sculptures.

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