scholarly journals Nanoparticles of γ-Sitoesterol and Ag on Clinoptilolite Zeolites

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Miguel Angel Hernandez ◽  
Martha Alicia Salgado ◽  
Roberto Portillo ◽  
Vitalii Petranovskii ◽  
Gabriela Itzel Hernández ◽  
...  

This work reports, the obtainment and stabilization of organic nanoparticles (γ-sitosterol) and Ag cations on the external area of Ca-clinoptilolite zeolite (Z17) are presented. The novelty of the present study lies in the formation and stabilization of nanoparticle organic molecules (γ-sitosterol) and inorganic cations (Ag) on the external area of Ca-clinoptilolite zeolite. The γ-sitosterol nanoparticles were obtained using Tournefortia hirsutissima and were later stabilized on the external area of Ca-clinoptilolite. The Ca-clinoptilolite-rich mineral as well as silver zeolitic minerals was characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM); elementary composition of the zeolitic mineral was determined by microanalyses (EDS) and high-resolution adsorption (HRADS) using N2 adsorption as a probe molecule. The EDS results about the exchange with Ag indicate the following sequence: Z17Ag03 > Z17Ag-09 > Z17Ag-06 > Z17Ag-01. The XRD studies indicate that only in the sample Z17Ag-03 there is an average crystal size of nanoparticles formed of 45.387 nm as determined by Sherrer’s equation. SEM images of clinoptilolite showed the presence of crystals with irregular and poorly defined box shapes that are typical for this type of zeolites. The nanoporosity of natural zeolites was studied by N2 adsorption; external areas were estimated through the De Boer and BET equations. The specific surface area calculated by BET equation, A SB , presents the following sequence: γ-SZ17 > Z17 > Z17Ag09 > Z17Ag03 > Z17Ag01 > Z17Ag06, while for the values of the external area obtained by the t method, the sequence is A ST : γ-Z17 > Z17 > Z17Ag03 > z17Ag09 > Z17Ag06 > Z17Ag01. For its part, the pore size distributions tell us that the sample Z17 exhibits a sharp multimodal distribution with pore size maxima happening at 1.262, 1.933, 3.824, and 4.282 nm. Z17Ag01 exhibits a bimodal distribution with pore size maxima occurring at 5.45 and 5.533 nm. The sample Z17Ag06 exhibits a sharp bimodal distribution with pore size maxima happening at 3.666 and 7.021 nm, and the sample Z17Ag09 exhibits a sharp trimodal distribution with pore size maxima happening at 1.853, 4.275 and 5.967 nm. Antibacterial activities of the exchanged samples with Ag on the external surface area were measured as a function of exchange level against Gram-positive bacteria (P. aureoginosa, K. pneumonie, and A. baumannii) and Gram-negative bacteria (E. coli, S. saprophyticcus, S. aureus, and E. feacalis); the selectivity sequence of the clinoptilolite and antibacterial activity results are presented. Z17Ag09 clinoptilolite seemed to be a promising antibacterial material.

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1238
Author(s):  
Garven M. Huntley ◽  
Rudy L. Luck ◽  
Michael E. Mullins ◽  
Nick K. Newberry

Four naturally occurring zeolites were examined to verify their assignments as chabazites AZLB-Ca and AZLB-Na (Bowie, Arizona) and clinoptilolites NM-Ca (Winston, New Mexico) and NV-Na (Ash Meadows, Nevada). Based on powder X-ray diffraction, NM-Ca was discovered to be mostly quartz with some clinoptilolite residues. Treatment with concentrated HCl (12.1 M) acid resulted in AZLB-Ca and AZLB-Na, the chabazite-like species, becoming amorphous, as confirmed by powder X-ray diffraction. In contrast, NM-Ca and NV-Na, which are clinoptilolite-like species, withstood boiling in concentrated HCl acid. This treatment removes calcium, magnesium, sodium, potassium, aluminum, and iron atoms or ions from the framework while leaving the silicon framework intact as confirmed via X-ray fluorescence and diffraction. SEM images on calcined and HCl treated NV-Na were obtained. BET surface area analysis confirmed an increase in surface area for the two zeolites after treatment, NM-Ca 20.0(1) to 111(4) m2/g and NV-Na 19.0(4) to 158(7) m2/g. 29Si and 27Al MAS NMR were performed on the natural and treated NV-Na zeolite, and the data for the natural NV-Na zeolite suggested a Si:Al ratio of 4.33 similar to that determined by X-Ray fluorescence of 4.55. Removal of lead ions from solution decreased from the native NM-Ca, 0.27(14), NV-Na, 1.50(17) meq/g compared to the modified zeolites, 30 min HCl treated NM-Ca 0.06(9) and NV-Na, 0.41(23) meq/g, and also decreased upon K+ ion pretreatment in the HCl modified zeolites.


2018 ◽  
Vol 8 (10) ◽  
pp. 1922 ◽  
Author(s):  
Enshirah Da’na ◽  
Amel Taha ◽  
Eman Afkar

Iron nanoparticles (FeNP) were synthesized using Acacia nilotica seedless pods extract. The synthesized FeNP were characterized by Fourier transform infrared (FTIR), UV/Vis spectroscopy, dynamic light scattering (DLS), electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The XRD pattern confirmed the synthesis of crystalline phase of α-Fe2O3. EDS spectroscopy showed the presence of elemental iron and oxygen, indicating that the nanoparticles are essentially present in oxide form. UV absorption in the range of 450–550 nm confirmed the formation of FeNP. DLS indicated an average FeNP particle size of 229 nm. The synthesized FeNP was tested for adsorption and oxidation degradation of methyl orange (MO) under different conditions and found to be effective in both degradation and adsorption processes. Furthermore, the synthesized FeNP has the potential to terminate the pathogenicity of several human opportunistic pathogens; belongs to gram-negative and gram-positive bacteria and one species of Candida as well.


1988 ◽  
Vol 121 ◽  
Author(s):  
Gregory C. Frye ◽  
Antonio J. Ricco ◽  
Stephen J. Martin ◽  
C. Jeffrey Brinker

ABSTRACTA novel technique for accurately obtaining nitrogen adsorption isotherms on thin porous films has been developed. These isotherms are useful for characterizing the surface area and pore size distribution of porous samples. The sensitivity to adsorbed nitrogen is increased by several orders of magnitude over conventional techniques by forming the test film on the substrate of a surface acoustic wave (SAW) device. This device functions as a microbalance able to detect less than 100 pg/cm2 of film. Surface areas and pore size distributions calculated from adsorption isotherms obtained with this technique on silicate sol-gel films are compared to those for bulk samples prepared from similar sol-gel solutions.


1987 ◽  
Vol 4 (1-2) ◽  
pp. 87-104 ◽  
Author(s):  
Bruce D Adkins ◽  
Jill B. Heink ◽  
Burtron H. Davis

Scanning electron microscopic data, X-ray diffraction patterns and porosity measurements are consistent with a structure for an Mo-A12O3 catalyst series containing a single surface layer of Mo up to the point where the Mo loadings exceed the amount required for a monolayer. For greater Mo loadings than required for a monolayer, three dimensional orthorhombic MoO3 is also present. The cumulative pore volume, on an alumina basis, does not appear to be significantly altered by MoO3 loadings up to about 15 wt.%. The BET surface area, on an alumina basis, remains constant with Mo loading. However, the apparent surface area calculated from mercury penetration data decreases with Mo loading. For these materials with cylindrical pores, the Broekhoff-deBoer model for the calculation of pore size distributions produced closer agreement to the mercury penetration pore size distribution. This is in contrast to materials composed of nonporous spheres where the Broekhoff-deBoer model provided poorer agreement to mercury penetration results than either the Cohan or a packed sphere model. The results show that, within a factor of two the pore size distributions calculated from nitrogen adsorption and mercury penetration data are comparable.


Clay Minerals ◽  
2007 ◽  
Vol 42 (2) ◽  
pp. 203-211 ◽  
Author(s):  
S.-H. Sun ◽  
J.-T. Ma ◽  
X.-H. Gao

AbstractZeolite ZSM-5 was synthesized successfully, in situ, on pyrokaolin microspheres (PKM) under hydrothermal conditions, without the use of an organic amine template. The utility of alkali-modified pyrokaolin microspheres (AMKM) was also evaluated. The resulting products were characterized using X-ray diffraction, scanning electron microscopy (SEM) and N2-adsorption isotherm data. The material containing ZSM-5 synthesized from the system PKM-additional silica-water had a large surface area and pore volume with significant enhancements in the micropore surface area and micropore volume. The SEM images show that the synthesis of zeolite ZSM-5 from pyrokaolin microspheres (PKM) led to the formation of polycrystalline aggregates <2 μm in size. The purity of the zeolite ZSM-5 produced was affected by both the pH value of the reactant system and the reaction temperature. In the system containing AMKM-additional silica-water, very little of the synthesized zeolite resided on the kaolin microspheres.


2008 ◽  
Vol 8 (2) ◽  
pp. 549-556 ◽  
Author(s):  
Asli Nalbant ◽  
Timur Dogu ◽  
Suna Balci

Nickel and copper incorporated MCM-41-like mesoporous nanocomposite materials prepared by the direct hydrothermal synthesis and the impregnation procedures showed highly attractive pore structure and surface area results for catalytic applications. The XRD patterns showed that characteristic MCM-41 structure was preserved for the materials synthesized following an impregnation procedure before the calcination step. The surface area of the Cu impregnated material with a quite high Cu/Si atomic ratio (0.19) was 631 m2/g. Very narrow pore size distributions with an average pore diameter of about 2.7 nm were obtained as a result of plugging of some of the smaller pores by Cu nanoballs. For lower metal to Si ratios (for instance for Ni/Si = 0.06) much higher surface area values (1130 m2/g) were obtained. In the case of nanocomposite materials synthesized by the direct hydrothermal route, MCM-41 structure was not destroyed for samples containing metal to Si atomic ratios as high as 0.12. In the case of materials containing Cu/Si and Ni/Si ratios over 0.2 wider pore size distributions and some decrease of surface area were observed.


2014 ◽  
Vol 79 (8) ◽  
pp. 1007-1017 ◽  
Author(s):  
Mozaffar Abdollahifar ◽  
Reza Zamani ◽  
Ehsan Beiygie ◽  
Hosain Nekouei

The micro-mesopores flowerlike ?-Al2O3 nano-architectures have been synthesized by thermal decomposition method using the synthesized AlOOH (boehmite) as precursor. After calcination at 500?C for 5 h, the obtained flowerlike ?-Al2O3 has similar structure like the AlOOH precursor. X-ray diffraction (XRD), FTIR, TG, FESEM and TEM techniques were used to characterize morphology and structure of the synthesized samples. The specific surface area (BET), pore volume and pore-size distribution of the products were determined by N2 adsorption-desorption measurements. The flowerlike ?-Al2O3 showed BET high specific surface area 148 m2 g-1 with total pore volume 0.59 cm3 g-1.


2019 ◽  
Vol 31 (9) ◽  
pp. 1926-1930
Author(s):  
Veenu Chugh ◽  
Sangeeta Sharma ◽  
Rimpi Mehani Ne'e Chopra

This paper describes the synthesis, spectral studies and antimicrobial properties of the complexes with the formula [M(C30H24N4O2)Cl2], where M = Fe(II), Co(II), Ni(II), Zn(II) and Cu(II). These complexes were prepared by yield effective template condensation of hexamethylenediamine and 2,2-dihydroxyindane-1,3-dione(ninhydrin). The synthesized complexes were characterized by elemental analysis, infrared spectra, thermogravimetric analysis, Mass spectrum, 13C NMR, molar conductance, electronic spectra, magnetic measurements. TGA and X-ray diffraction studies were used to ascertain the crystal structure and thermal stability of the complexes. The antimicrobial properties of complexes against two Gram-positive bacteria and two Gram-negative bacteria were evaluated by Agar well diffusion technique. Streptomycin and chloramphenicol were taken as standard antibiotics. The results shows that some of the complexes have potential to act as antibacterial agents.


2012 ◽  
Vol 594-597 ◽  
pp. 522-526
Author(s):  
Peng Ran Song ◽  
Chang Ming Wang

Microstructure is a important index of soil physical, mechanical and engineering properties, SEM images and computer image processing technology make the soil microstructure research developing rapidly in recent years, but the researches on the influence factors and important degree are rare. Process the images form scanning electron microscopy test with the image processing toolbox of MATLAB. Fractal dimensions, porosities and pore size distributions are calculated in different analyzing windows, thresholds and magnifications. The results show that:1) As the results of the experiment influenced greatly by the smaller analyzing windows, in order to get the real calculation value, the medium section was processed; 2) Fractal dimension values are less influenced than porosities and pore size distributions by different thresholds; 3) Too big magnification can cause inaccurate fractal dimensions. Porosities and pore size distributions are inverse growing with increasing of magnification.


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