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Register a new userDetermination of the Specific Surface Acidity of Al2O3 / CdO System by TPD Method using Pyridine as a Base
تحديد الحموضة السطحية النوعية للجملة Al2O3/CdO باستخدام طريقة TPD باعتماد البيريدين كأساس
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Tishreen University ورقة بحثية
Publication date
2017
fields
Chemistry
and research's language is
العربية
Created by
Shamra Editor
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تم في هذا العمل تحضير ست عينات مختلفة التركيب المولري من جملة الأكسيد المشترك Al2O3/CdO بطريقة الترسيب المشترك. حضرت العينات من محاليل مشبعة لأملاح الكادميوم و الألمنيوم باستخدام الأمونيا المركزة كعامل مرسب عند قيمة pH=8 و بعد الترسيب و التجفيف تم تكليس العينات عند الدرجة 400oC لمدة ساعتين (بالصعق). قسمت العينة بعد التكليس إلى قسمين من أجل تحديد الحموضة السطحية باستخدام طريقة المج الحراري المبرمج (TPD). تمت قياسات TG-DTA على القسم الأول مباشرةً لتعيين الفاقد الوزني و ذلك من خلال برنامج حراري في المجال 20-900°C بسرعة تسخين 10°C/min , أما القسم الثاني فقد تم نقعه في البيريدين السائل و ترك لمدة 24 ساعة مع التحريك المستمر و بعد ذلك جفف الناتج عند الدرجة 120°C لمدة 4 ساعات للتخلص من البيريدين الممتز فيزيائياً ثم أجريت على هذا القسم قياسات TG-DTA ضمن الشروط نفسها للقسم الأول. درست المنحنيات التفاضلية لمعرفة الفاقد الوزني بسبب امتزاز-مج البيريدين على المواقع الحمضية, وجد أن العينة AC8(1-1) أعطت أعلى قيمة للحموضة السطحية 0.47m.mol/g , بينما أعطت العينة AC8(1-0.25) أقل قيمة للحموضة السطحية 0.11m.mol/g.
In this work, six different samples of the Al2O3 / CdO system were prepared in a co-precipitation method. Samples were prepared from saturated solutions for cadmium and aluminum salts using concentrated ammonia as a precipitating agent at pH = 8 and after settling and drying the sample was calcined at 400°C for two hours. In order to studied the surface acidity by temperature programmed desorption (TPD) method. The calcined sample was divided to two parts: The TG-DTA measurements was carried on for the first part in order to determine the loss weight using thermal program in the range 20-900°C and 10°C/min. The second part was impregnated in pyridine for 24h, and dried at 120°C to remove the physical adsorbed pyridine and the TG-DTA measurements were performed at the same conditions for the first part. Differential curves were studied to calculate the weight loss produced by the desorption of pyridine. The AC8 (1-1) showed the highest surface acidity value (0.47m.mol / g), while the sample AC8 (1-0.25) gave the lowest acidity surface value (0.11m.mol / g).
References used
LIPPENS, B.C.; STEGGERDA, J.J. Physical and chemical aspects of adsorbents and catalysts. Ed., B.G. Linsen, Acad. Press, London and New York, 1970, Ch. 4, 171-211
DDEWAELE, O; FROMENT,G,F. TAP Study of mechanism and kinetics of the adsorption and composition of methane on Ni/Al2O3 and NiO/Al2O3 . J, Catalysis Vol. 184, 1999, 499-513
ZHANG,X; LIU,J;JING, Y;XIE,Y. Support effects on the catalytic behavior of NiO/AL2O3 for oxidative dehydrogenation of ethan to ethylene Appl Catalysis A , general 240. 2003, 143-150
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Tow samples of Al2O3/CdO mixed oxide were prepared by co-precipitation method at
PH 8 using concentrated ammonia as precipitated agent.The mixed system was prepared by
mixing aluminum chloride solution with cadmium chloride solution and aluminum ni
trate
solution with cadmium nitrate solution which prepared in previous work.
The nature of anions affected pore radii anions.
The results showed the increasing of micro porosity.
Samples were prepared in different ways of Al2O3 / CdO and with one specific mole
Al / Cd: 1-0.25 mol, in the wet joint deposition method. - The thermal disintegration
of aluminum nitrate Al(NO3)3.9H2O and Cd(NO3)2.4H2O nitrate, and the reaction of
aluminum nitrate Al(NO3)3.9H2O and cadmium nitrate Cd(NO3)2.4H2O, with
NH4HCO3 with appropriate reactivity ratios, Sodium laureth sulfate (ALS), and the
effect of various methods of preparation on the properties of the textile structure of
the common oxide group Al O /CdO
2 3
.
It was found that the values of porous structure factors vary according to the
method of preparation, the two samples prepared in the manner of thermal
disintegration. The total pore size is slightly increased, while the mean pore radius
decreases from 2.71nm to 2.37nm, in contrast to the two hydrothermal heating
samples.
The total pore size increases significantly to 0.553ml /g. (SLS), a decrease in the
radius of the middle pores, and an increase in the value of the surface area.
A sensitive, simple and selective spectrofluorimetric method
has been proposed for determination Captopril (CPT) in pure form
and pharmaceutical preparations. This method depends on the
formation of complex between Captopril and Copper (II) at
pH=3.5.
Multichannel Analysis of Surface Waves (MASW) is increasingly applied in
earthquake engineering and geotechnical problems, because of simple field
procedures, time and cost saving. It can allow for maximum areal coverage,
thus reduces the number o
f needed boreholes.
This study illustrates the importance of the use of active and passive MASW
to measure the average shear wave velocities of the upper surface layers (upper
30m) of the city of Irbid in North Jordan by integrating the outputs of the
active and passive approaches, and by investigating the relationship between
the estimated average shear wave velocity with the following geotechnical
variables, Bearing capacity, depth of embedment, and soil thickness.
In this research, the electrochemical reduction of hydrogen process
and the factors affecting the reduction potential have been studied
in this research. The effect of acid concentration on the shifting of
the volt-ampero-metric curves that expres
s the reduction process
and so its effect on both the reduction potential value of hydronium
ions on drop mercury electrode, and the speed value of reduction
reaction was studied. Then an amount of pyridine as organic
substance was added to a specific volume of acid in a specific
concentration to figure out the relationship between the amount of
pyridine added and the cathode current of the reaction to find out
the effect of added pyridine on the reaction speed and the
relationship between the amount of added pyridine and the
hydrogen reduction potential.
Pyridine was added to amount of acid to study the effect of
theaddition on the hydrogen reduction over potential.
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