scholarly journals Boosting the Catalytic Performance of Co/Mg/La Catalyst for Ammonia Synthesis by Selecting a Pre-Treatment Method

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 941
Author(s):  
Hubert Ronduda ◽  
Magdalena Zybert ◽  
Wojciech Patkowski ◽  
Andrzej Ostrowski ◽  
Przemysław Jodłowski ◽  
...  

The influence of the calcination process on the physicochemical properties and catalytic behavior of the Co/Mg/La catalysts for ammonia synthesis has been investigated. The catalysts were prepared using the different thermal pre-treatment methods prior to the activation, i.e., drying and calcination, and the respective activities for ammonia synthesis were assessed. It was found out that changing from air calcination prior to activation to direct activation of the co-precipitated species led to the different catalytic performances. The most favorable catalytic performance was achieved with Co/Mg/La prepared by calcination in air. Detailed characterization methods, employing e.g., XRPD, H2-TPD, N2-TPD, CO2-TPD, SEM, and TEM, showed that the superior catalytic behavior of this catalyst was attributed to its strong basicity and favorable adsorption properties toward hydrogen and nitrogen.

Author(s):  
E Y. Wang ◽  
J. T. Cherian ◽  
A. Madsen ◽  
R. M. Fisher

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.


2019 ◽  
Vol 37 (No. 4) ◽  
pp. 246-251 ◽  
Author(s):  
Joanna Tkaczewska ◽  
Maciej Wielgosz ◽  
Piotr Kulawik ◽  
Marzena Zajac

The influence of drying temperature on the characteristics and gel properties of gelatine from Cyprinus carpio L. skin was studied. Gelatine was extracted from the carp skin using NaOH and ethanol pre-treatment method, extracted in water in 45°C and then dried in 4 different temperatures: 50, 70, 80°C and freeze-dried. The  electrophoresis and functional properties of gelatines were investigated. Freeze drying allowed to obtain a high gelling force, and all other methods did not give satisfactory results. The proteins in gelatines dried at higher temperatures separated by electrophoresis gave severely blurred bands. It may be explained by thermal hydrolysis of collagen fibrils. Freeze drying is the only effective method for drying this product, which can be used in industry.


Talanta ◽  
2007 ◽  
Vol 71 (3) ◽  
pp. 1172-1179 ◽  
Author(s):  
Y. Fajardo ◽  
E. Gómez ◽  
F. Garcias ◽  
V. Cerdà ◽  
M. Casas

Desalination ◽  
2010 ◽  
Vol 250 (2) ◽  
pp. 557-561 ◽  
Author(s):  
J.J. Lee ◽  
M.A.H. Johir ◽  
K.H. Chinu ◽  
H.K. Shon ◽  
S. Vigneswaran ◽  
...  

Author(s):  
Avinash V Borgaonkar ◽  
Ismail Syed ◽  
Shirish H Sonawane

Molybdenum disulphide (MoS2) is a popularly used solid lubricant in various applications due to its superior tribological behaviour. However, it possesses poor wear resistance which requires further improvement. In the present study efforts have been made to enhance the tribological properties of pure MoS2 coating film by doping TiO2 nanoparticles as a reinforcement material. The Manganese phosphating is selected as a pre-treatment method to improve the bond strength between coating and substrate. The coating is bonded with the substrate material employing sodium silicate as a binder. The effects of wt. % of TiO2 onto the mechanical properties of composite MoS2-TiO2 coating such as hardness and bond strength have been studied. In addition coating microstructure before and after experimental test was studied using optical microscope and scanning electron microscope. It was also found that with increase in wt. % addition of TiO2 upto 15% into MoS2 base matrix, the hardness of coating increases proportionally. Beyond 15 wt. % addition of TiO2, the coating becomes brittle in nature. This leads to reduction in the scratch resistance.


2021 ◽  
Author(s):  
Soo Takasu ◽  
Isabella Supardi Parida ◽  
Yoshihiro Kojima ◽  
Toshiyuki Kimura ◽  
Kiyotaka Nakagawa

We demonstrated the conversion of GAL-DNJ into DNJ improves mulberry leaves bioavailability and constructed a novel enzymatic-based method to induce the hydrolysis of GAL-DNJ to DNJ.


2012 ◽  
Vol 575 ◽  
pp. 80-83
Author(s):  
Zhen Jia ◽  
Zheng Xin Gao ◽  
Guo Liang Li ◽  
Cheng Yu Wang ◽  
Hua Ma

This paper introduced the preparation method of PF-CaCO3/fast-growing poplar composite. Adopting AFM, DSC and SEM samples characterization methods was to explore the intersolubility of this PF and nano-CaCO3. And WPG and contact angles of treated veneers were measured. The results showed that this treatment method improved greatly density and hydrophilic of poplar veneers.


2020 ◽  
Vol 15 (3) ◽  
pp. 818-828
Author(s):  
Miradatul Najwa Muhd Rodhi ◽  
Fazlena Hamzah ◽  
Ku Halim Ku Hamid

Gallic acid and quercetin equivalent were determined in the crude extract of matured leaves Aquilaria malaccensis and Aquilaria subintegra. The leaves of both Aquilaria species were dried at 60 °C for 24 hours, ground and sieved into particle size of 250, 300, 400, 500, and 1000 µm. Then, each particle size of leaves was soaked in distilled water with a ratio of 1:100 (w/v) for 24 hours and undergoes the pre-treatment method by using ultrasonicator (37 kHz), at the temperature of 60 °C for 30 minutes. The crude extracts were obtained after about 4 hours of hydrodistillation process. The highest concentration of gallic acid and quercetin equivalent was determined in the crude extract from the particle size of 250 µm. The kinetics of pancreatic lipase inhibition was further studied based using the Lineweaver-Burk plot, wherein the concentration of p-NPP as the substrate and pancreatic lipase were varied. Based on the formation of the lines in the plot, the crude leaves extract of both Aquilaria species exhibit the mixed-inhibition on pancreatic lipase, which indicates that in the reaction, the inhibitors were not only attached to the free pancreatic lipase, but also to the pancreatic lipase-(p-NPP) complex. The reaction mechanism was similar to non-competitive inhibition; however the value of dissociation constant, Ki, for both inhibition pathways was different. The inhibition shows an increment in Michaelis-Menten constant (Km) and a reduction in the maximum pancreatic lipase activity (Vm) compared to the reaction without Aquilaria spp. crude extracts (control). This proved that the inhibition occurred in this reaction. Copyright © 2020 BCREC Group. All rights reserved 


2014 ◽  
Vol 2 (16) ◽  
pp. 5616-5619 ◽  
Author(s):  
Xiang Wang ◽  
Lihong Xiao ◽  
Honggen Peng ◽  
Wenming Liu ◽  
Xianglan Xu

SnO2 with a nano-rod morphology shows a superior catalytic performance over SnO2 with other morphologies for CO oxidation. The SnO2-rods’ catalytic behavior is very similar to that of a noble metal catalyst.


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