scholarly journals SINTESIS DAN KARAKTERISASI FAUJASIT DARI ABU LAYANG : Kajian Pengaruh Waktu Sintesis Terhadap Stabilitas Termal Struktur Faujasit (Kinetics of Faujasite Formation from Fly Ash)

2019 ◽  
Vol 2 (2) ◽  
pp. 10
Author(s):  
Sutarno Sutarno ◽  
Arief Budyantoro

Faujasite was hydrothermally synthesized from fly ash at 100oC in alkaline solution by reflux with 5M HCl and fusion with NaOH (weight ratio of NaOH/fly ash = 1.2) pretreatments. Kinetics of faujasite formation was performed by variation of hydrothermal time (0-120 hours). Thermal stability of faujasite from fly ash was tested at 400-900oC and was compared with commercial zeolite Y. The solid products were characterized by X-ray diffraction method. Results showed that faujasite was formed through dissolution of fly ash components such as quartz, mullite and amorphous aluminosilicates (0-3 hours) followed by crystallization to form faujasite (6-48 hours). In longer hydrothermal time (48-72 hours), faujasite transformed into zeolite P and completely formed hydroxysodalite after 120 hours. X-ray diffraction pattern showed that thermal stability of faujasite from fly ash was relatively lower than that of commercial zeolite Y. Faujasite from fly ash transformed into amorphous phase at 800oC whereas commercial zeolite Y transformed into amorphous phase at 900oC.

2010 ◽  
Vol 4 (1) ◽  
pp. 26-32
Author(s):  
Sutarno Sutarno ◽  
Yateman Arryanto

Faujasite was hydrothermally synthesized from fly ash at 100oC in alkaline solution by reflux with various concentration of HCl and fusion with NaOH (weight ratio of NaOH/fly ash = 1.2) pretreatments. Thermal stability of faujasite from fly ash was tested at 400-900oC and was compared with commercial zeolite Y. The solid products were characterized by X-ray diffraction method, chemical analysis and nitrogen adsorption (BET). Results showed that synthesis of faujasite from fly ash via fusion pretreatment with NaOH has resulted faujasite selectively, however, the faujasite obtained still showed relatively low thermal stability due to its relatively low of Si/Al mol ratio. Reflux pretreatment with HCl was an effective method not only to increase the Si/Al mol ratio but also to decrease the metal impurities in the fly ash sample. Synthesis of faujasite from fly ash via combination of reflux with HCl and fusion with NaOH pretreatment has resulted faujasite selectively with higher Si/Al mol ratio. Faujasite obtained from fly ash via combination of reflux with HCl and fusion with NaOH pretreatment showed thermal stability as high as commercial zeolite NaY.   Keywords: fly ash, reflux with HCl, fusion with NaOH, faujasite and thermal stability


Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 963
Author(s):  
Xueqing You ◽  
Qingjian Hu ◽  
Xiaoyong Hu ◽  
Hanxian Chen ◽  
Wenbin Yang ◽  
...  

Poor compatibility between nanocellulose crystals (NCCs) and major polymers has limited the application of NCC as bio-reinforcements. In this work, an effective and ultra-fast method was investigated to significantly improve the hydrophobicity of NCC by using poly(methylhydrogen)siloxane (PMHS) as modifier. PMHS possessed amounts of reactive –Si–H groups and hydrophobic –CH3 groups. The former groups were reactive with the hydroxyl groups of NCC, while the latter groups afforded NCC very low surface energy. As the weight ratio of PMHS to NCC was only 0.0005%, the hydrophobicity of NCC was significantly improved by increasing the water contact angle of NCC from 0° to 134°. The effect of weight ratio of PMHS to NCC and the hydrogen content of –Si–H in PMHS on the hydrophobicity and thermal stability was investigated in detail by Fourier transform infrared spectroscopy (FTIR), (X-ray Diffraction) XRD and (thermogravimetric analysis) TGA. The results indicated that PMHS chains were covalently grafted onto NCC and PMHS modification improved the thermal stability of NCC.


2010 ◽  
Vol 5 (3) ◽  
pp. 278-282 ◽  
Author(s):  
Sutarno Sutarno ◽  
Yateman Arryanto

Faujasite was hydrothermally synthesized from fly ash at 100oC in alkaline solution by reflux with 5M HCl and fusion with NaOH pretreatments. Phase transformation in the formation of faujasite was performed by variation of NaOH/fly ash weight ratios and hydrothermal times. The solid products were characterized by X-ray diffraction method. Results showed that faujasite was formed through dissolution of fly ash components such as quartz, mullite and amorphous aluminosilicates followed by crystallization to form faujasite. Arranging the NaOH/fly ash weight ratio as well as hydrothermal time can selectively form faujasite. Faujasite with crystallinity of 97.06%, Si/Al ratio of 2.68, and specific surface area of 452.93 m2/g was successfully formed using NaOH/fly ash weight ratio of 1.2 for hydrothermal time of 72 hours. In more concentrated alkaline solution as well as for longer hydrothermal time, faujasite was completely transformed into hydroxysodalite as the final product. Keywords: fly ash, faujasite, and phase transformation.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Shanta Biswas ◽  
Taslim U. Rashid ◽  
Abul K. Mallik ◽  
Md. Minhajul Islam ◽  
M. Nuruzzaman Khan ◽  
...  

A novel composite material was prepared from prawn shell derived chitosan (CHT) and locally available kaolinite-rich modified Bijoypur clay (MC) using a facile technique in which dilute acetic acid was used as a solvent for dissolving chitosan and composite fabrication whereas distilled water was used for preparing the clay dispersion. Bijoypur clay mainly consists of kaolinite clay mineral and it was modified with the dodecyl amine to make it organophilic. Morphology and properties of the composites (different weight ratio of MC and CHT) have been studied and compared with those of pure CHT and MC. Purification and modification of Bijoypur clay were investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier transformed infrared spectroscopy (FTIR) analyses. The fabrication of CHT-MC composites was confirmed by FTIR analysis. Thermogravimetric analysis (TGA) and differential scanning colorimetry (DSC) were used to investigate the thermal stability of the composites. It was observed that dispersed clay improves the thermal stability and enhances the hardness of the matrix systematically with the increase of clay loading. In this study, a better insolubility in both acidic and alkaline media of the composites is also observed compared to pure chitosan.


1998 ◽  
Vol 514 ◽  
Author(s):  
M. F. Wu ◽  
A. Vantomne ◽  
S. Hogg ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.


2021 ◽  
Vol 875 ◽  
pp. 116-120
Author(s):  
Muhammad Alamgir ◽  
Faizan Ali Ghauri ◽  
Waheed Qamar Khan ◽  
Sajawal Rasheed ◽  
Muhammad Sarfraz Nawaz ◽  
...  

In this study, the effect of SBR concentration (10 Phr, 20 Phr & 30 Phr ) on the thermal behavior of EPDM/SBR blends was studied. Thermogravimetric analysis (TGA) was used to check weight loss of samples as function of temperature by heating upto 600°C. X-ray diffraction (XRD) was performed to determine quality and % crystallinity of the elastomer blends. It was seen that % crystallinity improved with an increase in the content of SBR in EPDM/SBR blends. TGA revealed that the thermal stability of EPDM/SBR blends has improved by 17% than neat EPDM. Carbon nano-coatings produced by sputtering have no beneficial influence on thermal behaviour of elastomers.


2005 ◽  
Vol 60 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Tong-Lai Zhang ◽  
Jiang-Chuang Song ◽  
Jian-Guo Zhang ◽  
Gui-Xia Ma ◽  
Kai-Bei Yu

Cobalt(II) and zinc(II) complexes of ethyl carbazate (ECZ), [Co(ECZ)3](NO3)2 and [Zn(ECZ)3] (NO3)2, were synthesized. Single crystals of these two compounds were grown from aqueous solutions using a slow evaporation method. Their structures have been determined by X-ray diffraction analysis. Both of them are monoclinic with space group P21/n. The complexes are further characterized by element analysis and IR measurements. Their thermal stabilities are studied by using TG-DTG, DSC techniques. When heated to 350 °C, only metal oxide was left for both complexes.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 767 ◽  
Author(s):  
Michal Lojka ◽  
Ondřej Jankovský ◽  
Adéla Jiříčková ◽  
Anna-Marie Lauermannová ◽  
Filip Antončík ◽  
...  

In this paper, magnesium oxychloride cement with stoichiometry 3Mg(OH)2∙MgCl2∙8H2O (MOC 3-1-8) was prepared and characterized. The phase composition and kinetics of formation were studied by X-ray diffraction (XRD) and Rietveld analysis of obtained diffractograms. The chemical composition was analyzed using X-ray fluorescence (XRF) and energy dispersive spectroscopy (EDS). Furthermore, scanning electron microscopy (SEM) was used to study morphology, and Fourier Transform Infrared (FT-IR) spectroscopy was also used for the analysis of the prepared sample. In addition, thermal stability was tested using simultaneous thermal analysis (STA) combined with mass spectroscopy (MS). The obtained data gave evidence of the fast formation of MOC 3-1-8, which started to precipitate rapidly. As the length of the time of ripening increased, the amount of MgO decreased, while the amount of MOC 3-1-8 increased. The fast formation of the MOC 3-1-8 phase at an ambient temperature is important for its application in the production of low-energy construction materials, which corresponds with the challenges of a sustainable building industry.


2005 ◽  
Vol 20 (10) ◽  
pp. 2682-2690 ◽  
Author(s):  
Yufang Zhu ◽  
Weihua Shen ◽  
Xiaoping Dong ◽  
Jianlin Shi

A stable mesoporous multilamellar silica vesicle (MSV) was developed with a gallery pore size of about 14.0 nm. A simulative enzyme, hemoglobin (Hb), was immobilized on this newly developed MSV and a conventional mesoporous silica material SBA-15. The structures and the immobilization of Hb on the mesoporous supports were characterized with x-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier transform infrared, ultraviolet-visible spectroscopy, and so forth. MSV is a promising support for immobilizing Hb due to its large pore size and high Hb immobilization capacity (up to 522 mg/g) compared to SBA-15 (236 mg/g). Less than 5% Hb was leached from Hb/MSV at pH 6.0. The activity study indicated that the immobilized Hb retained most peroxidase activity compared to free Hb. Thermal stability of the immobilized Hb was improved by the proctetive environment of MSV and SBA-15. Such an Hb-mesoporous support with high Hb immobilization capacity, high activity, and enhanced thermal stability will be attractive for practical applications.


2018 ◽  
Vol 6 (35) ◽  
pp. 17171-17176 ◽  
Author(s):  
Lasse Rabøl Jørgensen ◽  
Jiawei Zhang ◽  
Christian Bonar Zeuthen ◽  
Bo Brummerstedt Iversen

The thermal stability of the high performance n-type Te-doped Mg3Sb1.5Bi0.5 system is investigated.


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