scholarly journals Development of semi-synthetic catalyst based on clay and their use in catalytic cracking of petroleum residue

2021 ◽  
Author(s):  
Oumarou Abdoulaye Dan Makaou ◽  
Soumahoro Gueu ◽  
Marou Gourouza ◽  
Kouassi Benjamin Yao
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Catalytic Cracking ◽  
Lanthanum Oxide ◽  
Structural Characteristics ◽  
Petroleum Residue ◽  
Acid Activation ◽  
Heavy Petroleum

AbstractTwo semi-synthetic clay-based catalysts were prepared. These catalysts were obtained by incorporating lanthanum oxide (Cat1) and chromium oxide (Cat2). They were then tested for catalytic cracking of a heavy petroleum residue (fuel). The two formulations were carried out in the presence of silica to improve their acidity then underwent an acid activation. The catalysts obtained were characterized by various methods (XRD, FTIR, ICP-OES, SEM). The results showed that the incorporation of oxides and the addition of silica improves the structural characteristics of the final products. The support used was a kaolinite rich clay, having a specific surface area of 15.26 m2/g and acidity of 14 meq/g. These values increase, respectively, to 456.14 m2/g and 50 meq/g for Cat1 and to 475.12 m2/g and 57 meq/g for Cat2. The influence of the type of oxide incorporated, the specific surface area, the porosity and the acidity of the catalysts on their catalytic activity was studied. The nature of the oxide used proved to be decisive on the quality of the catalyst. Thus Cat1, prepared with lanthanum oxide, showed the best performance in cracking the petroleum residue achieving a conversion rate of 74.13% compared to 66.53% for cat2.

scholarly journals Nanocomposite Materials Based on Electrochemically Synthesized Graphene Polymers: Molecular Architecture Strategies for Sensor Applications

Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 149
Author(s):  
André Olean-Oliveira ◽  
Gilberto A. Oliveira Brito ◽  
Celso Xavier Cardoso ◽  
Marcos F. S. Teixeira
Keyword(s):  
Conducting Polymers ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrochemical Sensors ◽  
Structural Characteristics ◽  
Low Cost ◽  
Large Specific Surface Area ◽  
Molecular Architecture ◽  
Sensor Applications

The use of graphene and its derivatives in the development of electrochemical sensors has been growing in recent decades. Part of this success is due to the excellent characteristics of such materials, such as good electrical and mechanical properties and a large specific surface area. The formation of composites and nanocomposites with these two materials leads to better sensing performance compared to pure graphene and conductive polymers. The increased large specific surface area of the nanocomposites and the synergistic effect between graphene and conducting polymers is responsible for this interesting result. The most widely used methodologies for the synthesis of these materials are still based on chemical routes. However, electrochemical routes have emerged and are gaining space, affording advantages such as low cost and the promising possibility of modulation of the structural characteristics of composites. As a result, application in sensor devices can lead to increased sensitivity and decreased analysis cost. Thus, this review presents the main aspects for the construction of nanomaterials based on graphene oxide and conducting polymers, as well as the recent efforts made to apply this methodology in the development of sensors and biosensors.

scholarly journals Effect of the electrolysis regime on the structural characteristics of honeycomb-like electrodes

2013 ◽  
Vol 32 (1) ◽  
pp. 79
Author(s):  
Nebojsa D. Nikolic ◽  
Goran Branković ◽  
Miomir G. Pavlović
Keyword(s):  
Surface Morphology ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Structural Characteristics ◽  
Hole Size ◽  
Porous Structures ◽  
Wall Width ◽  
Copper Electrodes ◽  
Hydrogen Bubbles

The effect of different current regimes of electrolysis on the micro- and nanostructural characteristics of open porous structures was examined by the analysis of honeycomb-like copper electrodes obtained by constant galvanostatic (DC) electrodeposition and by regimes of pulsating (PC) and reversing (RC) current. An increase in the number of holes formed by detached hydrogen bubbles, the decrease in wall width between holes and changes in surface morphology around holes from cauliflower-like agglomerates of copper grains to dendrites were observed in the following order: the DC, PC and RC regime. The hole size formed in the RC regime was smaller than the hole size formed in the DC and PC regimes. Analysis of the obtained structural characteristics showed that the specific surface area of the honeycomb-like electrodes was increased by the application of the PC and RC regimes in relation to the DC regime.

Porosity, Specific Surface Area and Effective Thermal Conductivity of Anisotropic Open Cell Lattice Structures

2005 ◽  
Author(s):  
Kiran Balantrapu ◽  
Deepti Rao Sarde ◽  
Christopher M. Herald ◽  
Richard A. Wirtz
Keyword(s):  
Thermal Conductivity ◽  
Specific Surface ◽  
Effective Thermal Conductivity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Structural Characteristics ◽  
Analytical Models ◽  
Lattice Structures ◽  
Open Cell ◽  
Thermally Conductive

Open-cell box-lattice structures consisting of mutually orthogonal thermally conductive cylindrical ligaments can be configured to have wide ranging porosity, a large specific surface area and effective thermal conductivity in a particular direction together with specified structural characteristics. Thermal and mechanical properties can be tuned (and anisotropy introduced) by specification of different filament diameter and pitch for the vertical and horizontal filaments. Analytical models for porosity, specific surface area and effective thermal conductivity of lattice structures having different ligament diameters and pitches (anisotropy) are developed. The models show that all three of these quantities are functions of three dimensionless lengths.   This paper was also originally published as part of the Proceedings of the ASME 2005 Heat Transfer Summer Conference.

scholarly journals Textural and structural modifications of saponite from Cerro del Aguila by acid treatment

Clay Minerals ◽  
2001 ◽  
Vol 36 (4) ◽  
pp. 483-488 ◽  
Author(s):  
M. Suárez Barrios ◽  
C. de Santiago Buey ◽  
E. García Romero ◽  
J. M. Martín Pozas
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Acid Treatment ◽  
Active Sites ◽  
Internal Surface ◽  
Acid Activation ◽  
Acid Attack ◽  
Surface Areas ◽  
Treated Sample

AbstractThe physicochemical properties of clays can be modified by acid treatment with inorganic acids. This treatment is usually referred to as ‘acid activation’, because it increases the specific surface area and the number of active sites of the solids. In the present study, the acid activation of saponite from Cerro del Aguila (Madrid, Spain) with HCl solutions was measured. Illite, quartz and small amounts of feldspar were found as impurities in the raw saponite.Acid treatments were carried out with different concentrations of HCl solutions. The samples obtained were characterized by mineralogical and chemical analyses, XRD, FT-IR spectroscopy, N2 adsorption-desorption isotherms and TEM. The acid attack, under the conditions employed, produced a progressive destruction of the structure of saponite by partial dissolution of the octahedral Mg(II) cations. Amorphous silica coming from the tetrahedral sheet of saponite was generated. The specific surface area of the most intensely treated sample (2.5% for 24 h) was doubled with respect to that of natural saponite. This increase in the surface area is due to the increase in both the external and internal surface areas.

scholarly journals Process improvement approach to the acid activation of smectite using factorial and orthogonal central composite design methods

2008 ◽  
Vol 73 (4) ◽  
pp. 487-497 ◽  
Author(s):  
Ljiljana Rozic ◽  
Tatjana Novakovic ◽  
Srdjan Petrovic
Keyword(s):  
Specific Surface ◽  
Central Composite Design ◽  
Surface Area ◽  
Specific Surface Area ◽  
Design Methods ◽  
Optimum Operating ◽  
Acid Activation ◽  
Liquid Ratio ◽  
Stirring Rate ◽  
Central Composite

The purpose of this study was to determine the effective operating parameters and the optimum operating conditions of an acid activation process within the framework of improvement of the process. Full two-level factorial and orthogonal central composite design methods were used successively. The examined parameters were the main and interaction effects of temperature, leaching time, acid normality, solid-to-liquid ratio and stirring rate. The selected process response was the leaching yield of the MgO content because Mg is the element most readily removed from the octahedral sheet, which affects the tendency for activation. Statistical regression analysis and analysis of variance were applied to the experimental data to develop a predictive model, which revealed that temperature, leaching time and acid normality exert the strongest influence on the specific surface area of smectite, whilst the solid-to-liquid ratio and the stirring rate have a secondary effect. Furthermore, the highest leaching yield of MgO was found to be 41.86 %, which is responsible for the increase in the specific surface area of up to 221 m2 g-1.

Preparation of heat-resistant alumina aerogels

1993 ◽  
Vol 8 (11) ◽  
pp. 2993-2999 ◽  
Author(s):  
Yasuyuki Mizushima ◽  
Makoto Hori
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Lanthanum Oxide ◽  
Barium Oxide ◽  
Supercritical Drying ◽  
High Specific Surface Area ◽  
Drying Methods ◽  
Alumina Aerogel ◽  
Alumina Aerogels

Alumina aerogels were prepared using supercritical drying methods, and their thermal properties were examined. The effects of several additives to the alumina aerogel and supercritical drying methods were examined in order to improve heat resistance. Silica, phosphoric oxide, barium oxide, lanthanum oxide, and SiC whisker were effective for maintaining a high specific surface area of the alumina aerogel at a temperature over 1200 °C. Silica was found to be the most effective among the additives. The addition of 10 mol % silica resulted in an alumina aerogel with the highest specific surface area, 114.3 m2/g at 1200 °C, and increased the transformation temperature to α alumina. Barium oxide and lanthanum oxide formed smaller crystals within the alumina, compared with those of alumina alone. SiC whisker caused many cracks in the alumina aerogel. When supercritically dried, the alumina aerogel was strengthened by treatment at higher temperature and pressure.

scholarly journals Effective cesium removal from Cs-containing water using chemically activated opaline mudstone mainly composed of opal-cristobalite/tridymite (opal-CT)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sunki Kwon ◽  
Yumi Kim ◽  
Yul Roh
Keyword(s):  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Chemical Properties ◽  
High Specific Surface Area ◽  
Acid Activation ◽  
Simple Modification ◽  
Physico Chemical ◽  
Acid And Base

AbstractOpaline mudstone (OM) composed of opal-CT (SiO2·nH2O) has high potential use as a cesium (Cs) adsorbent, due to its high specific surface area (SSA). The objective of this study was to investigate the Cs adsorption capacity of chemically activated OM and the adsorption mechanism based on its physico-chemical properties. We used acid- and base-activation methods for the surface modification of OM. Both acid- and base- activations highly increased the specific surface area (SSA) of OM, however, the base-activation decreased the zeta potential value more (− 16.67 mV), compared to the effects of acid-activation (− 6.60 mV) or non-activation method (− 6.66 mV). Base-activated OM showed higher Cs adsorption capacity (32.14 mg/g) than the others (acid: 12.22 mg/g, non: 15.47 mg/g). These results indicate that base-activation generates pH-dependent negative charge, which facilitates Cs adsorption via electrostatic attraction. In terms of the dynamic atomic behavior, Cs cation adsorbed on the OM mainly exist in the form of inner-sphere complexes (IS) containing minor amounts of water molecules. Consequently, the OM can be used as an effective Cs adsorbent via base-activation as an economical and simple modification method.

scholarly journals Rekayasa mikrosfer Zeolit sebagai sebagai penyangga katalis FCC dengan bahan baku mineral Kaolin

2018 ◽  
Vol 11 (3) ◽  
pp. 149
Author(s):  
Tjokorde Walmiki Samadhi ◽  
Febrinaldo Eka Nugraha
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Catalytic Cracking ◽  
Hydrothermal Reaction ◽  
Textural Properties ◽  
Fluid Catalytic Cracking ◽  
Preliminary Evaluation ◽  
Fcc Catalysts

Develpment of Zeolite as FCC catalyst support using Kaolin as a raw materialThis study is a preliminary evaluation of the feasibility of manufacturing fluid catalytic cracking (FCC) catalysts using Indonesian kaolins. A Belitung kaolin sample was  spray-dried to form kaolin microspheres, and divided into two parts. One part is processed by low calcination (at 700-850 oC) and the other by high calcination (1000 oC). Metakaolins produced by these treatments were mixed, and reacted with concentrated NaOH solution hydrothermally at 100-110 oC. A reaction period of 18-24 hours produced faujasite phase growth on the microsphere surface, as identified by X-ray diffraction and SEM morphology characterization. Measurement of textural properties by nitrogen adsorption produced a specific surface area of 10.5-142.1 m2/g, pore volume of 0.007-0.097 cm3/g, and  median pore size of 13.1-15.6 Å. Except for the pore diameter, these properties were still substantially lower than FCC catalysts described in the literature. ANOVA data analysis identified calcination time and the interaction between calcination temperature and hydrothermal reaction period as significant effects. Based on this analysis, the specific surface area may be increased by setting the low calcination period at low level (approximately 2 hours) while simultaneously setting  calcination temperature and hydrothermal reaction period at high levels (approximately 850 oC and 24 hours, respectively).Keywords: kaolin microsphere, Belitung, metakaolin, faujasite, FC AbstrakKajian ini merupakan evaluasi awal kelayakan pembuatan katalis fluid catalytic cracking (FCC) dari kaolin Indonesia. Kaolin Belitung mula-mula diolah menjadi mikrosfer kaolin dengan pengeringan sembur. Mikrosfer kemudian dipilah menjadi dua bagian, satu bagian dikenai perlakuan kalsinasi rendah (pada temperatur 700-850 oC) dan sisanya dikenai kalsinasi tinggi (1000 oC). Metakaolin hasil kalsinasi pada kedua tingkat temperatur ini dicampurkan, dan direaksikan dengan larutan NaOH secara hidrotermal pada temperatur 100-110 oC. Reaksi hidrotermal selama 18-24 jam membentuk fasa faujasit pada permukaan mikrosfer kaolin, yang diidentifikasi dengan metode difraksi sinar-X dan dengan pengamatan morfologi menggunakan metode SEM. Karakterisasi tekstural produk dengan adsorpsi nitrogen menghasilkan luas permukaan spesifik sebesar 10,5-142,1 m2/g, volume pori 0,007-0,097 cm3/g, serta median diameter pori 13,1-15,6 Å. Selain diameter pori, sifat-sifat tekstural ini masih kurang dibandingkan dengan katalis-katalis FCC yang dipaparkan di literatur. Pengolahan data percobaan dengan metode ANOVA mengidentifikasi periode waktu kalsinasi rendah serta interaksi antara temperatur kalsinasi rendah dan periode reaksi hidrotermal sebagai faktor-faktor yang menentukan luas permukaan spesifik. Berdasarkan analisis ini, luas permukaan dapat ditingkatkan dengan memilih waktu kalsinasi rendah yang relatif singkat (sekitar 2 jam), dan mengatur temperatur kalsinasi dan periode waktu reaksi hidrotermal secara serempak pada tingkat tinggi (masing-masing sekitar 850 oC dan 24 jam).Kata kunci: mikrosfer kaolin, Belitung, metakaolin, faujasit, FCC

Photocatalytic Property of Rice Husk Char/TiO2 Composite Prepared by Low-Temperature Method

2016 ◽  
Vol 848 ◽  
pp. 77-81 ◽  
Author(s):  
Xu Cheng ◽  
Yue Ming Li ◽  
Biao Wang ◽  
Jian Ming Jiang
Keyword(s):  
Thermal Treatment ◽  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Structural Characteristics ◽  
Photocatalytic Property ◽  
Low Temperature Preparation ◽  
Temperature Preparation

In this paper, low-temperature preparation of rice husk char/TiO2 composite was developed by utilizing agriculture waste. nanosized TiO2 particles were successfully loaded to rice husk char by in-situ thermal treatment of impregnated rice husk. The structural characteristics and photocatalytic activities of obtained composites were investigated. The specific surface area of rice husk char was enlarged due to the catalytic effect of loaded TiO2 during thermal treatment. The porous rice husk char matrix combined with nanosized TiO2 particles offered large specific surface area and good photocatalytic property. This low-temperature preparation method provided a promising way to reuse the waste biomass and extended the applications of charcoal.

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