تحضير وتوصيف أكسيد الحديد المكبرت

الموضوعات

علوم بحتة وطبيعية

روابط وملفات

التعريف والنوع

رقم الوثيقة

0c5d0ce8-91b5-4222-b47b-b1657c21efe4

رقم العقد

0

نوع الوسائط

Crawler

نوع المحتوى

الرسائل العلمية

صيغة المصدر

رسائل ماجيستير

نوع الملف

pdf text

أسماء الملفات

1962042_1.pdf

بيانات النشر

ترجمة العنوان

Preparation And Characterization Of Sulfated Iron Oxide

ألقاب المؤلفين

[{"name_ar":"علي النزاع الحمد","title_ar":"اعداد","title_en":"Preparation"},{"name_ar":"محمد نصوح علايا","title_ar":"اشراف","title_en":"Supervision"}]

اللغة

Arabic

المصدر والدورية

اسم المصدر

تحضير وتوصيف أكسيد الحديد المكبرت

المحتوى والصفحات

عدد الصفحات

118

ترجمة الملخص

Pure iron hydrogel (FeOOH) was prepared by drop-wiseaddition of30 wt.% ammoniasolution to a stirred molar solution of Fe(NO3)3. 9H2O at pH= 9.5−10.0. The vigorous stirring was continuedfor 3 hrs, left over night, washing with bidistillatedwater till free from NO3−ions, and finally dried at 120oC. Three samples of 5, 10, 15 wt.% SO42−/FeOOH were prepared by vigorous stirring the appropriate amount of 1 M H2SO4solution with dried FeOOH for 4 hrs. The slurries were left over night and then dried at 120oC. The prepared samples were calcined at 300oCand 500oC for 4 hrs.The structural properties of the sulfated iron oxide were studied by thermal analysis (TG−DTA), XRD and FT-IR spectra.Thetexturalcharacteristics of the obtained catalysts were determined from the analysis of the data of nitrogen adsorption at -196 oCK, by using the most conventional methods, i.e., BET, t-plots, αs-plots, DR equation and pore size distribution. The surface acidity was determined by potentiometric titration with n-butylamine in acetonitril and pyridine adsorption.The TG-DTA curves for FeOOH show three endothermic effects at< 400oC, with peaks at 100oC,225oCand 310oC, which due to the removal ofphysisorbed water, chemically water as well as the decomposition of hydrated species, i.e. removal of OHgroups.These effects were accompanied by two steps in TG curveat 50−210oCand 210−350oC with 5 wt% and 3 wt% weight losses.The TG curve indicates no further loss in the range 350−800oC. The DTA curves of sulfated samples show two endothermic effects their peaks were at ~95oC and ~250oC, which accompanied with two steps in TG curves, with weight loss of 8.0−9.4 wt% at 350oC were observed. Also, no further loss in the range of 350−525oC, after that the DTA curves show endothermic effects their peaks appear at 600−650oC. The TG curves show one step for 5SFeO in therange of 600-800oC, but for 10SFeO and 15SFeO samples show two steps in the same range,due to the decomposition of sulfate to liberateas SO3. The total TG% wasincreases with the increasing of sulfate loading, i.e. from 9.8 to 19.2 wt%.The XRD curvesof pure FeOOH, and sulfated samples calcined at500oC did not show the characteristic lines of Fe2O3or any other phase, i.e., they were amorphous. The sulfate hinders the crystallization and sintering of the iron oxides.The FT-IR spectra of FeOOH andthe calcined products at 300oCand500oC show the characteristic bands of the symmetric stretching vibration of O –Fe− O, the bending vibrations of adsorbed water and the stretching vibration of OH. The sulfated samples show in addition to the above peaks the characteristic bands of inorganic chelating bidentated sulfate,i. e., the symmetric and asymmetric stretching vibrations of S = O and S − O bonds.The adsorption isotherms of nitrogen at -196 oCfor FeOOH and sulfated iron oxides are typical Type IV with hysteresis loops. The t−and αs−plotsof the original sample and its calcined products as well as the sulfated samples show upward deviations due to the capillary condensation in the mesopores. The SBET, Stand Sαvalues are in good agreement.The results indicate that the loading of iron oxide by sulfate ion causes an increase of specific surface area. The textural properties were affected strongly by thermal treatment. Thus, SBET, VT, Voand Vmesoof catalysts are decreased with rising the calcination temperature. These properties are dependingalso on the percentage of sulfate loading. Thus for original samples show maxima in SBET, VT, Voand Vmesoat 10wt.% SO42−. Whereas, for xSFeO−300 and xSFeO−500 samples the.The mean pore radii of all the samples as well as the pore obtained from pore size distribution calculations are in the range of mesopores. The unloaded samples show maximum for the 300-product. The loaded iron hydrogel show no change in rawith increasing of loading. The SFeO−300 products show a gradual increase but the SFeO−500 products show a gradual decrease in rawith increasing of sulfate content. The pores are differingin shape and type, i.e. cylindrical and cavities in shape.All the samples contain strong acidic sites, i.e.Eivalues are in the range 184−515 mV. The inductive effect of S=O bonds cause a decrease in the electronic cloud of the Lewis site Fe3+and hence increases the acid strength of the site. The total surface acidity of unloaded iron oxide is decreased with rising the calcination temperature. The total surface acidity of sulfated original samples isdecreased with increasing the sulfate content. The SFeO−300 samples show maximum acidity for 10wt%SO42−loading, whereas SFeO−500 samplesshow minimum acidity for10wt%SO42−loading.The FT-IR spectra of pyridine adsorbed on all samples indicate the presence of both Brønsted and Lewis acidic sites. The intensity of the bands depends on the calcination temperature and the percent of sulfate loaded. The prepared samples are good solid superacid.

إشراف وإعداد

الإشراف

محمد نصوح علايا

الإعداد

علي النزاع الحمد

الاقتباسات الببليوغرافية