scholarly journals Textural Properties of Hybrid Biomedical Materials Made from Extracts ofTournefortia hirsutissimaL. Imbibed and Deposited on Mesoporous and Microporous Materials

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Miguel Ángel Hernández ◽  
Fernando Rojas ◽  
Roberto Portillo ◽  
Martha Alicia Salgado ◽  
Vitalii Petranovskii ◽  
...  
Keyword(s):  
Composite Material ◽  
High Resolution ◽  
Hybrid Materials ◽  
External Surface ◽  
Total Pore Volume ◽  
Textural Properties ◽  
External Surface Area ◽  
Biomedical Materials ◽  
Organic Part ◽  
Inorganic Supports

Our research group has developed a group of hybrid biomedical materials potentially useful in the healing of diabetic foot ulcerations. The organic part of this type of hybrid materials consists of nanometric deposits, proceeding from the Mexican medicinal plantTournefortia hirsutissimaL., while the inorganic part is composed of a zeolite mixture that includes LTA, ZSM-5, clinoptilolite, and montmorillonite (PZX) as well as a composite material, made of CaCO3and montmorillonite (NABE). The organic part has been analyzed by GC-MS to detect the most abundant components present therein. In turn, the inorganic supports were characterized by XRD, SEM, and High Resolution Adsorption (HRADS) of N2at 76 K. Through this latter methodology, the external surface area of the hybrid materials was evaluated; besides, the most representative textural properties of each substrate such as total pore volume, pore size distribution, and, in some cases, the volume of micropores were calculated. The formation and stabilization of nanodeposits on the inorganic segments of the hybrid supports led to a partial blockage of the microporosity of the LTA and ZSM5 zeolites; this same effect occurred with the NABE and PZX substrates.

scholarly journals Layered Materials with Catalytic Applications: Pillared and Delaminated Zeolites from MWW Precursors

2012 ◽  
Vol 2012 ◽  
pp. 1-35 ◽  
Author(s):  
Urbano Díaz
Keyword(s):  
Surface Area ◽  
Molecular Sieves ◽  
Active Sites ◽  
External Surface ◽  
Synthesis Method ◽  
Textural Properties ◽  
Inorganic Materials ◽  
External Surface Area ◽  
Inorganic Supports ◽  
Zeolitic Materials

Delaminated and pillared zeolites are an innovative family of molecular sieves which introduced a different concept inside the synthesis of active catalysts or inorganic supports. These types of materials exhibit an elevated accessibility due to their open structure, characterized by the high external surface area without imposed restrictions controlled by the pore sizes. These open zeolites are conformed by crystalline ordered (pillared zeolites) or disordered (delaminated zeolites) individual layers, exhibiting textural properties which are favorable to carry out catalytic processes in which it is necessary to employ catalysts with completely accessible active sites. The elevated external surface area of these zeolites is profitable to generate more specific organic-inorganic materials, acting in this case as stable inorganic matrixes. The preparation of this open type-zeolites family is based on the modification of, previously synthesized, zeolitic precursors which are preexpanded to obtain the final delaminated or pillared zeolites which exhibit very different physicochemical properties compared with the starting precursors. Along this paper, the most relevant MWW-type high accessible zeolitic materials will be considered. Their nature, characteristics, and reactivity will be shown in the function of the employed synthesis method for their preparation and the postsynthesis treatments carried out, tuning their properties.

scholarly journals Characterization and Catalytic Behaviour of Co3(PO4)2–AlPO4 Catalysts

1998 ◽  
Vol 16 (4) ◽  
pp. 285-293 ◽  
Author(s):  
M.R. Mostafa ◽  
F.Sh. Ahmed
Keyword(s):  
Pore Radius ◽  
Surface Acidity ◽  
Total Pore Volume ◽  
Textural Properties ◽  
Acid Sites ◽  
Adsorption Of Nitrogen ◽  
Amorphous Structures ◽  
Ft Ir ◽  
Catalytic Behaviour ◽  
The Mean

Co3(PO4)2, AlPO4 and the binary system Co3(PO4)2-AlPO4 with different compositions were prepared by the coprecipitation method. The structural properties of these samples were determined using XRD, DTA and FT-IR techniques. The textural properties were determined from the adsorption of nitrogen at 77 K. The surface acidity was measured by a calorimetric titration method. The samples were tested as catalysts in the dehydration of ethanol and isopropanol using a pulse microcatalytic technique. The data obtained from XRD and FT-IR indicate the amorphous structures of the prepared catalysts. An increase in Co3(PO4)2 content led to a decrease in the surface area and in the total pore volume and an increase in the mean pore radius. The surface acidity of the catalyst depends on the chemical composition; the surface acidity increased with an increase in the AlPO4 content. The dehydration temperature and the distribution of acid sites are important parameters in determining the selectivity and activity of the catalyst.

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 The Amounts of Water Adsorbed to the Surface of Clay Minerals at the Plastic Limit

2017 ◽  
Vol 64 (3-4) ◽  
pp. 155-162
Author(s):  
Aleksandra Gorączko ◽  
Andrzej Olchawa
Keyword(s):  
Surface Area ◽  
External Surface ◽  
Solid Phase ◽  
Water System ◽  
Basal Spacing ◽  
Plastic Limit ◽  
X Ray Diffraction ◽  
External Surface Area ◽  
X Ray ◽  
Water Layers

AbstractThe paper presents results of a study on the amount of water associated with the solid phase of the clay water system at the plastic limit. Two model monomineral clays, namely kaolinite, and montmorillonite, were used in the study. The latter was obtained by gravitational sedimentation of Na-bentonite (Wyoming).The calculated mean number of water molecule layers on the external surface of montmorillonite was 14.4, and water in interlayer spaces constituted 0.3 of the water mass at the plastic limit.The number of water layers on the external surface of kaolinite particles was 63, which was related to the higher density of the surface electrical charge of kaolinite compared to that of montmorillonite.The calculations were made on the basis of the external surface area of clays and the basal spacing at the plastic limit measured by an X-ray diffraction test. The external surface area of clays was estimated by measuring sorption at a relative humidity p/p0 = 0.5.

scholarly journals Plasma Catalysis: Distinguishing between Thermal and Chemical Effects

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 185 ◽  
Author(s):  
Guido Giammaria ◽  
Gerard van Rooij ◽  
Leon Lefferts
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Thermal Effects ◽  
External Surface ◽  
Plasma Chemistry ◽  
Internal Surface ◽  
Plasma Power ◽  
External Surface Area ◽  
Internal Surface Area ◽  
Chemical Effects

The goal of this study is to develop a method to distinguish between plasma chemistry and thermal effects in a Dielectric Barrier Discharge nonequilibrium plasma containing a packed bed of porous particles. Decomposition of CaCO3 in Ar plasma is used as a model reaction and CaCO3 samples were prepared with different external surface area, via the particle size, as well as with different internal surface area, via pore morphology. Also, the effect of the CO2 in gas phase on the formation of products during plasma enhanced decomposition is measured. The internal surface area is not exposed to plasma and relates to thermal effect only, whereas both plasma and thermal effects occur at the external surface area. Decomposition rates were in our case found to be influenced by internal surface changes only and thermal decomposition is concluded to dominate. This is further supported by the slow response in the CO2 concentration at a timescale of typically 1 minute upon changes in discharge power. The thermal effect is estimated based on the kinetics of the CaCO3 decomposition, resulting in a temperature increase within 80 °C for plasma power from 0 to 6 W. In contrast, CO2 dissociation to CO and O2 is controlled by plasma chemistry as this reaction is thermodynamically impossible without plasma, in agreement with fast response within a few seconds of the CO concentration when changing plasma power. CO forms exclusively via consecutive dissociation of CO2 in the gas phase and not directly from CaCO3. In ongoing work, this methodology is used to distinguish between thermal effects and plasma–chemical effects in more reactive plasma, containing, e.g., H2.

scholarly journals Characterization and comparison of walnut shells-based activated carbons and their adsorptive properties

2020 ◽  
Vol 38 (9-10) ◽  
pp. 450-463
Author(s):  
Xiya Li ◽  
Jieqiong Qiu ◽  
Yiqi Hu ◽  
Xiaoyuan Ren ◽  
Lu He ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Activated Carbons ◽  
Low Cost ◽  
Total Pore Volume ◽  
Textural Properties ◽  
Hydrothermal Carbonization ◽  
Bet Surface Area ◽  
Activation Process ◽  
Walnut Shells ◽  
Adsorption Desorption

The production of low-cost biologically activated carbons (BACs) is urgent need of environmental protection and ecological sustainability. Hence, walnut shells were treated by traditional pyrolysis, direct KOH impregnation and combined activation composed of hydrothermal carbonization and two-step H3PO4- and pyrolysis-activation process to obtain porous carbon with high adsorption capacity. It was found that the best adsorption capacity for iodine and organic dye methylene blue (MB) can be obtained using the KOH impregnation at impregnation ratio of 1:1 or combined activation comprising of 2 h H3PO4 activation and 1 h pyrolysis activation at 1000°C. The produced KOH, H3PO4/pyrolysis activated BACs at the optimum conditions are superior to that of commercial ACs, 9.4 and 1.3 times for MB removal, 4 and 4.5 times for iodine number respectively. Characterization results demonstrated their porous structure with very good textural properties such as high BET surface area (1689.1 m2/g, 1545.3 m2/g) and high total pore volume (0.94 cm3/g, 0.96 cm3/g). The N2 adsorption-desorption isotherm of H3PO4/pyrolysis activated hydrochar suggested the co-existence of micro and meso-pores. Moreover, they are more effective for the removal of Fe(III) and Cr(VI) from aqueous solution than the commercial AC, suggesting a promising application in the field of water treatment.

Synthesis and Characterization of Luminescence Eu3+/Polyurethane Composite Material

2014 ◽  
Vol 884-885 ◽  
pp. 247-250 ◽  
Author(s):  
Kai Sheng ◽  
Jie Lin Wang ◽  
Ying Li ◽  
Yi Han Wang ◽  
Meng Xue Xu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Composite Material ◽  
Rare Earth ◽  
Hybrid Materials ◽  
Chain Extender ◽  
Synthesis And Characterization ◽  
Rare Earth Ion ◽  
Polyurethane Composite ◽  
Small Molecule Ligands

Selecting lactam 2,6-pyridinedicarboxamide (PDCA) as the ligand and 1,4-butanediol as chain extender, we prepare polyurea polyurethane PDCA-PU; then, introduction of rare earth ion Eu3+ and small molecule ligands 1,10-phenanthroline (phen), synthesized binary and ternary polyurethane composite containing Eu3+, and comparing the fluorescence properties of the material. We investigated the thermal stability and luminescence properties of hybrids and found that the ternary hybrid materials exhibit better thermal stability and stronger emission intensity.

Carbon-embedded mesoporous Nb-doped TiO2 nanofibers as catalyst support for the oxygen reduction reaction in PEM fuel cells

2016 ◽  
Vol 4 (17) ◽  
pp. 6540-6552 ◽  
Author(s):  
Esmaeil Navaei Alvar ◽  
Biao Zhou ◽  
S. Holger Eichhorn
Keyword(s):  
Titanium Dioxide ◽  
Oxygen Reduction Reaction ◽  
Polymer Coating ◽  
External Surface ◽  
Catalyst Support ◽  
Pem Fuel Cells ◽  
Reduction Reaction ◽  
External Surface Area ◽  
Tio2 Nanofibers ◽  
Doped Titanium Dioxide

Embedding carbon via polymer coating and reductive calcination to increase the conductivity and external surface area of mesoporous Nb-doped titanium dioxide nanofibers.

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