scholarly journals Changes in crystal structure, thermal behaviour and surface area of a bentonite by acid activation

2007 ◽  
pp. 1-14
Author(s):  
M. ÖNAL
Keyword(s):  
Crystal Structure ◽  
Surface Area ◽  
Thermal Behaviour ◽  
Acid Activation

Comparative Acid Leaching Study of Mongolian Muscovite and Montmorillonite Clay Minerals

2021 ◽  
Vol 323 ◽  
pp. 21-27
Author(s):  
Gendenjamts Oyun-Erdene ◽  
Dolgormaa Anudari ◽  
Luvsandagva Mandakhsaikhan ◽  
Tsoodol Zolzaya ◽  
Jadambaa Temuujin
Keyword(s):  
Crystal Structure ◽  
Porous Structure ◽  
Structure Formation ◽  
Surface Area ◽  
Clay Minerals ◽  
Acid Leaching ◽  
Isomorphic Substitution ◽  
Acid Activation ◽  
High Porosity ◽  
X Ray

Acid activation is the most commonly used method to enhance the chemical and physical properties of clay minerals. Porous structure formation behavior depends on the crystal structure of clay minerals. Within the same structure of clay minerals, their resistance to acid also varies. Acid leaching has been used to increase the surface area of clay minerals and obtain solids with high porosity and many acidic sites. This paper is focused on the results of acid leaching of Mongolian clay minerals (montmorillonite and muscovite). Both clay minerals belong to a group of phyllosilicates with the 2:1 crystal structure. The influence of acid concentration and leaching time on the porous properties of silica was studied. Initially, the montmorillonite was pre-treated by a simple physical purification methods. The montmorillonite and muscovite were acid leached by a 10% hydrochloric acid solution in an autoclave at 120°C for 10h. X-ray diffraction (XRD), X-ray fluorescence analysis (XRF), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and the surface area used for characterization of the raw and leached samples. The surface area of leached montmorillonite increased up to 77% and muscovite up to 63%. Clay mineral’s swelling character and isomorphic substitution of the octahedral layer show the main influence on porous structure formation.

A simple tactic synthesis of hollow porous graphitic carbon nitride with significantly enriched photocatalytic performance

2021 ◽  
Author(s):  
Vellaichamy Balakumar ◽  
Manivannan Ramalingam ◽  
Chitiphon Chuaicham ◽  
KARTHIKEYAN SEKAR ◽  
K. Sasaki
Keyword(s):  
Crystal Structure ◽  
Surface Area ◽  
Carbon Nitride ◽  
Photocatalytic Performance ◽  
Porous Graphitic Carbon ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Modified Surface

Hollow porous graphitic carbon nitride (porous CN) was synthesized via a simple tactic method, and the resulting porous CN showed an effectively modified surface area, crystal structure and enhanced photocatalytic...

scholarly journals Synthesis and investigation of neptunium zirconium phosphate, a member of the NZP family: crystal structure, thermal behaviour and Mössbauer spectroscopy studies

2017 ◽  
Vol 46 (35) ◽  
pp. 11626-11635 ◽  
Author(s):  
D. M. Bykov ◽  
R. J. M. Konings ◽  
C. Apostolidis ◽  
A. Hen ◽  
E. Colineau ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mössbauer Spectroscopy ◽  
Infrared Spectroscopy ◽  
Thermal Behaviour ◽  
Zirconium Phosphate ◽  
Mossbauer Spectroscopy ◽  
Rietveld Analysis ◽  
Mößbauer Spectroscopy ◽  
Spectroscopy Studies

We synthesized a new NZP-type neptunium zirconium phosphate Np0.29Zr2(PO4)3 and investigated it by Rietveld analysis, infrared spectroscopy and Mössbauer spectroscopy.

scholarly journals Investigation of activated Al-pillared clay efficiency in vegetable oil purification

2004 ◽  
pp. 31-36 ◽  
Author(s):  
Gizela Lomic ◽  
Erne Kis ◽  
Etelka Dimic ◽  
Ranko Romanic
Keyword(s):  
Surface Area ◽  
Vegetable Oil ◽  
Total Pore Volume ◽  
Textural Properties ◽  
Sample Surface ◽  
Pillared Clay ◽  
Acid Activation ◽  
Micropore Surface Area ◽  
Natural Clays ◽  
Oil Purification

This paper represents a contribution to the applicability of natural clays and their derivates as adsorbents in the process of purification of vegetable oil. Investigation of textural properties of raw and purified clay samples reveals that during acid activation and Al-pillaring, BET and micropore surface area increases significantly. However, bleaching capacity of clay and its derivates is not determined by using sample surface area, but rather sample total pore volume. Surface area, especially micropore surface area contributes to removal of smaller molecules. This was confirmed by successful elimination of moisture and volatile materials by samples with an appropriate micropore structure. Used samples of clay and its derivates do not significantly influence acid and peroxide values of raw sunflower oil during its treatment.

scholarly journals Nanosized TiO2Photocatalyst Powder via Sol-Gel Method: Effect of Hydrolysis Degree on Powder Properties

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Nor Hafizah ◽  
Iis Sopyan
Keyword(s):  
Crystal Structure ◽  
Surface Area ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Gel Method ◽  
Sol Gel Method ◽  
Hydrolysis Degree ◽  
Method Effect ◽  
Powder Properties ◽  
Dta Curves

NanosizedTiO2powder was synthesized via sol-gel method using titanium tetraisopoxide (TPT) as the precursor. Mol ratios of water to TPT were varied from 1 (Powder A), 2 (Powder B), 3 (Powder C), and 4 (Powder D) to evaluate effect of hydrolysis degree. TG/DTA curves showed that amorphous phase turned to anatase crystal structure at ca. 415, 337, 310, and339∘C for Powders A, B, C, and D, respectively. XRD analysis showed that all the synthesizedTiO2powders were 100% in anatase form with Powders B and C showing considerably higher crystallinities. The powders obtained at lower water to TPT mol ratios were spherical in shape and they became bar-like shapes higher mol ratios. The lower hydrolysis degree led to higher surface area of the Powder A (24.8 m2/g) compared to Powder B (14.6 m2/g). From phenol photocatalytic measurement, Powder B was the most efficient attributed to its higher crystallinity.

scholarly journals Influence of surface modification by sulfuric acid on coking coal's adsorption of coking wastewater

2017 ◽  
Vol 76 (3) ◽  
pp. 555-566 ◽  
Author(s):  
Lihui Gao ◽  
Hong Wen ◽  
Quanzhi Tian ◽  
Yongtian Wang ◽  
Guosheng Li
Keyword(s):  
Sulfuric Acid ◽  
Zeta Potential ◽  
Surface Area ◽  
Pore Volume ◽  
Ash Content ◽  
Raw Material ◽  
Acid Activation ◽  
Coking Wastewater ◽  
Hydrophobic Properties ◽  
Coking Coal

Coking coal, the raw material of a coke plant, was applied to the adsorption of coking wastewater. In this study, coking coal was directly treated with sulfuric acid to improve its surface properties and adsorption ability. Acid treatment was carried out at various concentrations, by varying from 0.001 to 1 mol/L. The samples were characterized by ash content analysis, scanning electron microscope (SEM), N2 adsorption-desorption analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), wettability analysis, and zeta potential analysis. These results demonstrated that H+ could react with inorganic minerals, which resulted in a significant variation of the chemical composition and the structure of coal surface. Furthermore, both the ash content and the surface content of O = C-O, C = O and C-O groups declined gradually as the concentration of sulfuric acid increased, while the surface area and pore volume of micropore, the lipophilic and hydrophobic properties, and zeta potential magnitude increased, resulting in enhanced hydrophobic and Van der Waals' forces between the fine coal and organic pollutants. Characterization modification showed a better performance in adsorption, the removal rate enhanced from 23% to 42% after treated by 1 mol/L sulfuric acid. It was concluded that the acid activation modified the lipophilic and hydrophobic properties, the surface charge properties, surface area and pore volume, the content of oxygen functional groups, all of which could be potentially useful in wastewater adsorption.

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