Reduction of Pd catalytic particle size by a double activation process

This study aims to look at the effect of bottom ash activation with NaOH on the morphological structure and content of the elements contained in bottom ash and see the effect of activation on the absorption of phosphate compounds in water by bottom ash. Bottom ash from PT SOCIMAS coal combustion has been activated with NaOH and has been used to adsorb phosphate. Phosphate used in the form of KH3PO4. Bottom ash was first characterized by SEM-EDS to see the morphological structure and the element content contained in the bottom ash. Bottom ash mass variations used are (1, 2, and 3 grams), and particle size (50-70 mesh, 70-110 mesh, and 110-140 mesh). The activation process lasts for 5 hours using 3 M NaOH, then washed to pH 7. The bottom ash is activated then characterized again with SEM-EDS to ensure the impurities present in the bottom ash are reduced. Furthermore, bottom ash is used to adsorb phosphate with time variations of 20, 40, and 60 minutes. The most effective adsorption capacity (6.39 mg / g) is at the 20th minute with a particle size of 110-140 mesh and a bottom ash mass of 1 gram. The Freundlich and Langmuir isotherm model is used to describe the phosphate ion adsorption isotherm by the bottom ash. Based on the data obtained, the isotherm model suitable for this research is the Freudlich (R2 = 0.9721) and Langmuir (R2 = 0.9505) isotherm model.

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The Chemical Reaction Mechanics of Bastnaesite in Low Temperature Activation Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.391-392.1278 ◽

2011 ◽

Vol 391-392 ◽

pp. 1278-1282

Author(s):

Xue Bian ◽

Tao Yang ◽

Wen Yuan Wu ◽

Gan Feng Tu

Keyword(s):

Particle Size ◽

Low Temperature ◽

Chemical Reaction ◽

Rare Earths ◽

New Method ◽

Activation Process ◽

Temperature Activation

Bastnaesite was activated at low temperature, and the results of XRD, SEM and Raman showed that the particle size of minerals increased firstly, and then decreased with increasing of temperature. The polarization of rare earths fluoride decreased in activation minerals. Using HCl leaching, the rare earths carbonate and rare earths fluoride were separated effectively, and 94.6% rare earths carbonate and only 0.07% rare earths fluoride was dissolved respectively. The results supplied a new method of bastnaesite decomposition.

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Pengaruh HCl terhadap Aktifasi Zeolit Alam Clipnotilolit-Ca Pada Penyerapan Pb(II)

Jurnal Riset Kimia ◽

10.25077/jrk.v11i2.355 ◽

2020 ◽

Vol 11 (2) ◽

pp. 80-88

Author(s):

Zilfa Zilfa ◽

Upita Septiani ◽

Mirawati Mirawati

Keyword(s):

Particle Size ◽

Adsorption Capacity ◽

Contact Time ◽

Metal Ion ◽

Activation Process ◽

Acid Activation ◽

Optimum Conditions ◽

Hcl Concentration ◽

Solution Volume

Research about the effect of HCl on the activation of clinoptilolite-Ca natural zeolite on Pb(II) absorption has been done. The purpose of this study is to determine the capacity of zeolite clinoptilolite-Ca activation by HCl can be used as an adsorbent. For analysis of the adsorption we used AAS whereas for zeolite characterization were used XRF and XRD. The analysis parameters are the effect of HCl concentration, particle size, adsorbent mass, contact time, total solution volume, concentration of Pb(II), and PH solution. These parameters were studied to determine the optimum conditions in the adsorption process. The optimum conditions absorption of Pb(II) for the acid activation process shows that the zeolite clinoptilolite-Ca can be used as an absorbent. The adsorption results show that the value of Pb(II) capacity in the activation process with HCl of 0.2 N produces adsorption capacity of 0.0821 mg/g, for particle size 125 µm produces and adsorption capacity 0.0821 mg/g, for an adsorbent mass of 0.1 g produces an adsorption capacity of 0.5110 mg/g, for contact time of 10 minutes is 0.5662 mg/g, for a metal solution volume of 12.5 mL is 0.5493 mg/g, for the concentration of metal ion solution 40 mg/L is 2.608 mg/g, and at pH = 7 is 4.923 mg/g. The output of several parameters can be concluded that the adsorption capacity of zeolite clinoptilolite-Ca to the absorption of Pb(II) is 4.923 mg/g. Characterization of zeolite adsorbents with XRF and XRD shows that the zeolite used is zeolite clinoptilolite-Ca.

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In-situX-ray diffraction activation study on an Fe/TiO2pre-catalyst

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

10.1107/s2052520614011238 ◽

2014 ◽

Vol 70 (3) ◽

pp. 498-509 ◽

Cited By ~ 4

Author(s):

Matthew K. Rayner ◽

David G. Billing ◽

Neil J. Coville

Keyword(s):

Particle Size ◽

Phase Transformation ◽

Calcination Temperature ◽

Rietveld Method ◽

Rutile Phase ◽

Quantitative Phase Analysis ◽

Activation Process ◽

Oxidation Study ◽

Treatment Experiment

This study focuses on the use ofin situpowder X-ray diffraction (PXRD) and quantitative phase analysis using the Rietveld method to monitor the structural properties of a titania-supported iron (10% Fe/TiO2) pre-catalyst during calcination (oxidation) and activation (reduction) in the temperature range 25–900°C. The TiO2oxidation study revealed an increase in anatase particle size before the anatase to rutile phase transformation, lending credibility to the bridging mechanism proposed by Kimet al.[(2007),Mater. Sci. Forum,534–536, 65–68]. Pre-catalyst oxidation experiments allowed for the determination of a suitable calcination temperature (450°C) of the pre-catalyst in terms of maximum hematite concentration and appropriate particle size. These experiments also confirmed that the anatase to rutile phase transformation occurred at higher temperatures after Fe addition and that anatase was the sole donor of Ti4+ions, which are known to migrate into hematite (Gennariet al., 1998), during the formation of pseudobrookite (Fe2TiO5) at temperatures above 690°C. Using the results from the oxidation experiments, two pre-catalyst samples were calcined at different temperatures; one to represent the preferred case and one to represent a case where the pre-catalyst had been excessively heated. Samples of the excessively heated catalysts were exposed to different reducing gas atmospheres (5, 10 and 100% H2/N2) and heated in thein situPXRD reactor, so that diffraction data could be collected during the activation process. The results show that reduction with gases containing low concentrations of H2(5 and 10%) led to the formation of ilmenite (FeTiO3) and we were able to show that both anatase and rutile are consumed in the reaction. Higher concentrations of H2led to the formation of magnetite (Fe3O4) and metallic iron (Fe0). We also noted a decrease in the anatase to rutile transformation temperature under reducing atmospheres when compared with the pre-catalyst heat-treatment experiment. A reduced calcination temperature prior to reduction allowed more facile Fe reduction.

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Application of Fuel Ash as a Microfiller in Cement Dispersion Systems

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1037.729 ◽

2021 ◽

Vol 1037 ◽

pp. 729-736

Author(s):

Victoria Petropavlovskaya ◽

Тatyana Novichenkova ◽

Kirill Petropavlovskii ◽

Olga V. Aleksandrova ◽

Hans Bertram Fischer

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

High Dispersion ◽

Cement Stone ◽

Activation Process ◽

Rheological Characteristics ◽

Dispersed System ◽

Stable Chemical ◽

Dispersion Systems ◽

Fuel Ash

The paper shows studies of modified cement compositions with micro-filler. As such a micro-filler, an ash product is used - an activated waste of an ash-and-slag mixture. The enriched aluminosilicate waste is characterized by a fairly stable chemical and particle size distribution. The used activation of the ash product allows for a more dense packing of particles in the composition of the binder dispersed system. The high dispersion of the ash component requires additional plasticization of the dispersed system. Despite the fact that during the activation process the destruction of large-pore particles remaining after flotation occurs, the introduction of a plasticizer also improves the rheological characteristics of the compositions, and, consequently, increases the strength and density of the modified cement stone with the addition of a microfiller.

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SEM and Auger microanalysis studies of Cu-Be dynode surfaces at each activation condition

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109768 ◽

1978 ◽

Vol 36 (1) ◽

pp. 524-525

Author(s):

T. Koshikawa ◽

Y. Fujii ◽

E. Sugata ◽

F. Kanematsu

Keyword(s):

Electron Emission ◽

Secondary Electron ◽

Secondary Electron Emission ◽

Life Time ◽

Activation Process ◽

Beam Diameter ◽

Activation Temperature ◽

Electron Multiplier ◽

Activation Condition ◽

Activation Conditions

The Cu-Be alloys are widely used as the electron multiplier dynodes after the adequate activation process. But the structures and compositions of the elements on the activated surfaces were not studied clearly. The Cu-Be alloys are heated in the oxygen atmosphere in the usual activation techniques. The activation conditions, e.g. temperature and O2 pressure, affect strongly the secondary electron yield and life time of dynodes.In the present paper, the activated Cu-Be dynode surfaces at each condition are investigated with Scanning Auger Microanalyzer (SAM) (primary beam diameter: 3μmϕ) and SEM. The commercial Cu-Be(2%) alloys were polished with Cr2O3 powder, rinsed in the distilled water and set in the vacuum furnance.Two typical activation condition, i.e. activation temperature 730°C and 810°C in 5x10-3 Torr O2 pressure were chosen since the formation mechanism of the BeO film on the Cu-Be alloys was guessed to be very different at each temperature from the results of the secondary electron emission measurements.

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