Effects of Catalyst-Support Interaction, Particle Size, and Surface Morphology

Author(s):  
JAMES A. CUSUMANO ◽  
RALPH A. DALLA BETTA ◽  
RICARDO B. LEVY
2018 ◽  
Vol 3 (1) ◽  
pp. 12 ◽  
Author(s):  
Zaimahwati Zaimahwati ◽  
Yuniati Yuniati ◽  
Ramzi Jalal ◽  
Syahman Zhafiri ◽  
Yuli Yetri

<p>Pada penelitian ini telah dilakukan isolasi dan karakterisasi bentonit alam menjadi nanopartikel montmorillonit. Bentonit alam yang digunakan diambil dari desa Blangdalam, Kecamatan Nisam Kabupaten Aceh Utara.  Proses isolasi meliputi proses pelarutan dengan aquades, ultrasonic dan proses sedimentasi. Untuk mengetahui karakterisasi montmorillonit dilakukan uji FT-IR, X-RD dan uji morfologi permukaan dengan Scanning Electron Microscopy (SEM). Partikel size analyzer untuk menganalisis dan menentukan ukuran nanopartikel dari isolasi bentonit alam. Dari hasil penelitian didapat ukuran nanopartikel montmorillonit hasil isolasi dari bentonit alam diperoleh berdiameter rata-rata 82,15 nm.</p><p><em>In this research we have isolated and characterized natural bentonite into montmorillonite nanoparticles. Natural bentonite used was taken from Blangdalam village, Nisam sub-district, North Aceh district. The isolation process includes dissolving process with aquades, ultrasonic and sedimentation processes.  The characterization of montmorillonite, FT-IR, X-RD and surface morphology test by Scanning Electron Microscopy (SEM). Particle size analyzer to analyze and determine the size of nanoparticles from natural bentonite insulation. From the research results obtained the size of montmorillonite nanoparticles isolated from natural bentonite obtained an average diameter of 82.15 nm.</em></p>


2021 ◽  
Vol 13 (4) ◽  
pp. 656-661
Author(s):  
Yiyan Lv ◽  
Qiwei Zhan ◽  
Xiaoniu Yu

Microbial-induced degradation of aromatic organic compounds and mineralization of zinc ions have attracted much attention because of its low cost, simple operation and quick response. This research, toluene was decomposed and made the concentration of carbonate ions increased accordingly by the enzymatic pressing of microorganisms, meanwhile carbonate ions mineralized zinc ions into carbonate precipitations. The composition and microstructure were analyzed systematically. The analysis results indicated that carbonate precipitations, basic zinc carbonate, could be successfully prepared by microbial method. The particle size of basic zinc carbonate was nanometer, and its shape was near-spherical. Furthermore, the phase composition, functional groups and surface morphology of the precipitations prepared by different methods were basically the same. This work provided a new method for remediation of zinc ion pollution based on the degradation of toluene.


2018 ◽  
Vol 10 (4) ◽  
pp. 82
Author(s):  
Koyel Kar ◽  
R. N. Pal ◽  
Gouranga Nandi

Objective: The objective of the present work was to conduct accelerated stability study as per international council for harmonisation (ICH) guidelines and to establish shelf life of controlled release dosage form of ropinirole hydrochloride and pramipexole dihydrochloride microspheres for a period of 6 mo.Methods: Most optimized batch of ropinirole hydrochloride and pramipexole dihydrochloride (F12 and M12 respectively) were selected and subjected to exhaustive stability testing by keeping the sample in stability oven for a period of 3 and 6 mo. Various parameters like surface morphology, particle size, drug content, in vitro drug release and shelf life were evaluated at 3 and 6 mo period. The surface morphology of the formulated microspheres was determined by scanning electron microscopy (SEM). The particle size of the microspheres was estimated by optical microscopy method. The drug content was assayed by the help of ultra-violet spectrophotometer (UV). The in vitro drug release was performed by using Paddle II type dissolution apparatus and the filtrate was analyzed by UV spectrophotometer. The shelf life of the optimized microspheres was calculated by using the rate constant value of the zero-order reaction.Results: A minor change was recorded in average particle size of F12 and M12 microspheres after storage for 6 mo. For F12 and M12, initially the particle size was 130.00 µm and 128.92 µm respectively and after 6 mo it was found to be 130.92 µm and 128.99 µm respectively. There was no change in surface morphology of F12 and M12 microspheres after 6 mo of storage. The shape of microspheres remained spherical and smooth after 6 mo. An insignificant difference of drug content was recorded after 6 mo compared to the freshly prepared formulation. For F12 and M12, 94.50% and 93.77% of the drug was present initially and after 6 mo 94.45% and 93.72% of the drug was recorded. In vitro drug release was recorded after 6 mo for F12 and M12. Initially, 97.99% and 97.69% of the drug was released till 14th hour respectively for F12 and M12. After 6 mo, 98.23% and 97.99% of the drug was released respectively. The percentage residual drug content revealed that the degradation of microspheres was low. Considering the initial percentage residual drug content as 100%, 99.94% of the drug was recorded for both F12 and M12. The shelf life for F12 and M12 was found to be 10 y 52 d and 10 y 70 d respectively which were determined by the zero-order kinetic equation.Conclusion: A more or less similar surface morphology, particle size, drug content and percent of drug release before and after stability study confirmed the stability of F12 and M12 microspheres after storage for 6 mo and prove the efficacy of the microspheres in the site-specific delivery of drugs in Parkinson’s disease.


2021 ◽  
Vol 16 (2) ◽  
pp. 320-330
Author(s):  
Fitriyah Wulan Dini ◽  
Helmiyati Helmiyati ◽  
Yuni K. Krisnandi

This work demonstrated the use of green material catalysts, produced from Sengon sawdust waste, to obtain nanocellulose biopolymers. The green material catalysts were utilized as catalysts support of TiO2−ZrO2 binary oxide in the form of nanocomposite materials with superior synergistic properties. The isolation of nanocellulose was achieved using a hydrolysis method with a yield of 63.40%. The TiO2 and ZrO2 nanoparticles have average particle sizes of around 25 and 15 nm, respectively, and the binary oxides of TiO2–ZrO2 pretained an average particle size of 30 nm were used. Furthermore, the nanocellulose combined with the TiO2−ZrO2 binary oxide had formed a cellulose/TiO2−ZrO2 nanocomposite with an average particle size of 30 nm. This indicates that the supporting nanocellulose can stabilize the nanoparticles and avoid aggregation. Moreover, the nanocomposites can be used as a catalyst for the conversion of glucose to 5-ethoxymethylfurfural (5-EMF). The catalytic activity increased with the nanoparticle effect obtained ZrO2, TiO2, TiO2-ZrO2, and cellulose and TiO2-ZrO2 nanocomposite, in 15.50%, 20.20%, 35.20%, and 45.50% yields, respectively. The best yield of 5-EMF was 45.50%, with reaction conditions of 1:1 TiO2–ZrO2 ratio, 4 h reaction time, and 160 °C reaction temperature. The use of nanocellulose biopolymer generated from Sengon sawdust waste in Indonesia provides a promising catalyst support material as an alternative green catalyst. In addition, the glucose carbohydrates can be converted to biofuel feedstocks in the development of a renewable alternative energy. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 


Author(s):  
SHIKHA KESHARVANI ◽  
PANKAJ KUMAR JAISWAL ◽  
ALOK MUKERJEE ◽  
AMIT KUMAR SINGH

Objective: The main objective of this study was to develop and evaluate the eudragit and HPMC coated metformin hydrochloride floating microspheres, in which HPMC helps in floating and eudragit as a coating material for a site-specific drug release in a controlled manner and the active moiety metformin used as anti-hyperglycemic agent. Methods: The floating microsphere was prepared by the solvent evaporation method incorporating metformin as a model drug. The prepared floating microsphere were characterized for particle size, %yield, drug loading and entrapment efficiency, compatibility study, %buoyancy, surface morphology and In vitro drug release and release kinetics. Results: The result metformin loaded floating microsphere was successfully prepared and the particle size range from 397±23.22 to 595±15.82 µm, the entrapment efficiency range from 83.49±1.33 to 60.02±1.65% and drug loading capacity range from 14.3±0.54 to 13.31±0.47% and %buoyancy range from 85.67±0.58 to 80.67±1.15%. The FT-IR and X-RD analysis confirmed that no any interaction between drug and excipient, and surface morphology confirmed those particles are sphere. The floating microsphere show maximum 96% drug release in pH 0.1N HCL and follow the Korsmeyer peppas model of the super case-2 transport mechanism. Conclusion: These results suggest that metformin loaded floating microspheres could be retain in stomach for long time and give site specific drug release in controlled manner.


1999 ◽  
Vol 566 ◽  
Author(s):  
Uday Mahajan ◽  
Marc Bielmann ◽  
Rajiv K. Singh

In this study, we have characterized the effects of abrasive properties, primarily particle size, on the Chemical Mechanical Polishing (CMP) of oxide films. Sol-gel silica particles with very narrow size distributions were used for preparing the polishing slurries. The results indicate that as particle size increases, there is a transition in the mechanism of material removal from a surface area based mechanism to an indentation-based mechanism. In addition, the surface morphology of the polished samples was characterized, with the results showing that particles larger than 0.5 μm are detrimental to the quality of the SiO2 surface.


2019 ◽  
Vol 7 (17) ◽  
pp. 4981-4987 ◽  
Author(s):  
Ruiyu Bao ◽  
Chen Chen ◽  
Jianxin Xia ◽  
Huiying Chen ◽  
Hua Li

The surface morphology and particle size of materials can be controlled using DEP technology.


2014 ◽  
Vol 12 (2) ◽  
pp. 131-141 ◽  
Author(s):  
Ikramul Hasan ◽  
Shovan Paul ◽  
Sharmin Akhter ◽  
Navid Jubaer Ayon ◽  
Md Selim Reza

Metformin HCl microspheres were prepared with the aim of increasing its bioavailability and decreasing gastrointestinal side effects by means of sustained action. Eudragit RSPO and Eudragit RLPO, polymers of different permeability characteristics were used to prepare different microspheres. Emulsification solvent evaporation technique using acetone as the internal phase and liquid paraffin as the external phase was the method of choice. Six formulations were prepared using two polymers. The effect of drug loading and polymeric property on the surface morphology, entrapment efficiency, particle size and release characteristics of the microspheres were examined. FTIR and DSC studies established compatibility of the drug with the polymers. SEM studies clearly revealed the effect of drug loading and polymeric nature on the surface morphology of the microspheres. Entrapment efficiencies were within 77.09-97.11% and particle size of all the batches were in the acceptable range. Release data were treated with different mathematical kinetic models. The drug release profile showed that Eudragit RSPO and Eudragit RLPO have opposite effect on drug release. On the other hand, increase in drug loading results in increased drug release. Kinetic modeling of in vitro dissolution profiles revealed that the drug release mechanism varies from diffusion controlled to anomalous type. Dhaka Univ. J. Pharm. Sci. 12(2): 131-141, 2013 (December) DOI: http://dx.doi.org/10.3329/dujps.v12i2.17611


2018 ◽  
Vol 11 (01) ◽  
pp. 1850011
Author(s):  
Lipeng Ren ◽  
Wei Wang ◽  
Chenglei Yu ◽  
Saisai Duan ◽  
Wenjing Ma ◽  
...  

In this work, Ni films with the thickness of 50[Formula: see text]nm were deposited on (110) silicon substrate by electron beam evaporation at the temperature of 125[Formula: see text]C, 300[Formula: see text]C and 500[Formula: see text]C. Graphene was prepared on Ni films by PECVD to study the effect of Ni film structure and surface morphology on the graphene grown by PECVD. The result shows that the particle size and surface roughness of Ni film increase, as the temperature of substrate go up. The Ni film deposited at 125[Formula: see text]C exhibits amorphous state, and the Ni films deposited at 300[Formula: see text]C and 500[Formula: see text]C exhibit (111) microcrystal structure. The graphene grown on the microcrystalline Ni film deposited at 300[Formula: see text]C is the bilayer structure with less defects and uniform morphology. The graphene prepared on the microcrystalline Ni film deposited at 500[Formula: see text]C has more defects, layers and obvious plane undulation. The analysis indicates that microcrystalline Ni film deposited at 300[Formula: see text]C can be used by PECVD at low temperature to prepare a bilayer graphene with less defects and uniform morphology.


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