scholarly journals Keggin-Al13 Polycations: Influence of Synthesis and Intercalation Parameters on the Structural Properties of Al-Pillared Clays

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1211
Author(s):  
Anderson Parodia ◽  
Janaina A. Prasniski ◽  
Francine Bertella ◽  
Sibele B. C. Pergher
Keyword(s):  
Structural Properties ◽  
Exchange Process ◽  
Micropore Volume ◽  
Pillared Clay ◽  
Pillared Clays ◽  
Basal Spacing ◽  
Synthesis Conditions ◽  
Adsorption Processes ◽  
Natural Clays ◽  
Pillaring Solution

Pillared clays are interesting materials with applications in catalysis and adsorption processes. To obtain these materials, several preparation procedures are necessary and must be optimized to tune the final properties of the resulting pillared clay. Therefore, this article reports the influence of synthesis parameters (temperature and concentration) of Keggin-Al13 polycations and different intercalation times (0.5 up to 72 h) on the structural properties of Al-pillared clays. The natural clays are from Brazil, and they are composed mainly of montmorillonite. By XRD, N2 sorption, XRF and 27Al NMR results of the Al-PILCs, we verified that the pillaring solution could be prepared at room temperature with an aging time of 24 h. For the cation exchange process, a period of at least 2 h is necessary to ensure the formation of pillared materials. The concentration of the Keggin-Al13 polycations was evaluated by using diluted pillaring solutions followed by applying re-pillaring procedures. After submitting the pillared clay to another pillaring process, the number of pillars in the interlamellar space increased; however, the micropore volume decreased concomitantly. Thus, by optimizing the synthesis conditions of the Keggin-Al13 polycations, Al-PILCs could be obtained with good values of basal spacing and specific surface area.

Influence of aluminium incorporation in the preparation of zirconia-pillared clay and catalytic performance in the acetalization reaction

Clay Minerals ◽  
2012 ◽  
Vol 47 (4) ◽  
pp. 453-463 ◽  
Author(s):  
S. Mnasri ◽  
N. Frini-Srasra
Keyword(s):  
Ethylene Glycol ◽  
Exchange Reaction ◽  
Catalytic Performance ◽  
Pillared Clay ◽  
Pillared Clays ◽  
Basal Spacing ◽  
Lewis Acidic Sites ◽  
Acidic Sites ◽  
Acetalization Reaction ◽  
The Stability

AbstractThe exchange reaction of Na-bentonite with zirconium pillars gives products which suffer from a loss of crystallinity, with basal spacing about 18 Å and surface area of 200 m2 g–1. Aluminium introduced in different amounts in the zirconium intercalated solution leads to an improvement in the stability and crystallinity of zirconia-pillared clays (Zr-PILCs) and creates pillared clays with new properties. Adding a small amount of Al (10 molar %) leads to an increase of d001 from 18 Å to 20.5 Å and an increase of the percentage of introduced zirconium from 16.71 to 21, expressed as ZrO2 wt.%, accompanied by an increase of the Brönsted and Lewis acidic sites. The acetalization of acetone with ethylene glycol was studied in order to compare the activity of PILCs. The results show that the yield of the aforementioned reaction depends strongly of the composition and acidity of the catalyst.

Thermal and Hydrothermal Stability of Al-Pillared Rectorites

2010 ◽  
Vol 178 ◽  
pp. 314-317 ◽  
Author(s):  
Hong Yan Xu ◽  
Xing Tong Chen ◽  
Ai Hong Guo
Keyword(s):  
Nitrogen Adsorption ◽  
Micropore Volume ◽  
Pillared Clay ◽  
Hydrothermal Stability ◽  
Basal Spacing ◽  
X Ray Diffraction ◽  
Mesopore Volume ◽  
X Ray ◽  
Naturally Occurring ◽  
Adsorption Desorption

Al-pillared rectorites (Al-REC) were synthesized from naturally occurring rectorite through exchange of interlamellar ions with hydroxyalumina polycations. Furthermore, Powder X-ray diffraction (XRD), Nitrogen adsorption-desorption isotherms, and Transmitting electronic microscopy (TEM) were applied in order to study the themal stability and hydrothermal stability of pillared materials. The Al-REC are thermally stable up to 800 °C. X-ray diffractograms of Al-REC calcined at 800 °C show a sharp and intense d001 peak, corresponding to a basal spacing of 2.75nm. In a 100% steam flow under atmospheric pressure at 800 °C for 20h, the characteristic d001 spacing of Al-REC decreases from 2.74 to 2.52nm, the sharp and intense d001 peak is still observed. And micropore area, mesopore volume and micropore volume retain 62, 33 and 67%, respectively, which affirms that this pillared clay has exceptional hydrothermal stability.

scholarly journals Removal of organic matter from wastewater using M/Al-pillared clays (M = Fe or Mn) as coagulants

2018 ◽  
Vol 78 (3) ◽  
pp. 534-544
Author(s):  
Khadidja Gouttal ◽  
Abderrezak Benghalem ◽  
Goussem Mimanne ◽  
Benhabib Karim
Keyword(s):  
Organic Matter ◽  
Water Oxidation ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Pillared Clay ◽  
Pillared Clays ◽  
Point Of Zero Charge ◽  
Strong Interactions ◽  
Basal Spacing ◽  
Adsorption Sites

Abstract This work is about organic matter removal from Sidi Bel Abbes wastewater plant (Algeria) by coagulation on pillared clays (PILCs) under pH and PZC (point of zero charge), conditions. Two pillared clays, M/Al-PILCs (M = Fe or Mn), were synthesized, characterized, and studied as coagulants. Results showed that Fe/Al-pillared clay exhibits superior efficiency, with 18% higher removal rate than the common coagulants alum (AS) and ferric chloride (FCl), and that sedimentation time has positive effect on turbidity removal, with 95.85% removal rate during 30 min. Moreover PILCs will not cause pH go down too low, which is an advantage for achieving the best overall treatment. The IR and UV bands' reduction reveals the breakdown fragmentation of high molecular weight organic substances into smaller units. The highest total organic carbon (supercritical water oxidation analysis) and chemical oxygen demand adsorption capacities (48.52% and 61.85% respectively) obtained for Fe/Al-PILC can be related to increased basal spacing between adjacent layers, creating favorable adsorption sites in the microporous system. The suggested adsorption mechanism involves strong interactions between pollutants and PILCs leading to PILC–pollutant complex formation.

scholarly journals Tailoring Properties of Resol Resin-Derived Spherical Carbons for Adsorption of Phenol from Aqueous Solution

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1736
Author(s):  
Karol Sidor ◽  
Tomasz Berniak ◽  
Piotr Łątka ◽  
Anna Rokicińska ◽  
Marek Michalik ◽  
...  
Keyword(s):  
Surface Composition ◽  
Micropore Volume ◽  
Gaseous Ammonia ◽  
Poly Vinyl Alcohol ◽  
Clear Correlation ◽  
Hno3 Solution ◽  
Synthesis Conditions ◽  
Adsorption Of Nitrogen ◽  
Oxygen Groups ◽  
Size Of Particles

The polycondensation of resorcinol and formaldehyde in a water–ethanol mixture using the adapted Stöber method was used to obtain resol resins. An optimization of synthesis conditions and the use of an appropriate stabilizer (e.g., poly(vinyl alcohol)) resulted in spherical grains. The resins were carbonized in the temperature range of 600–1050 °C and then chemically activated in an aqueous HNO3 solution, gaseous ammonia, or by an oxidation–reduction cycle (soaking in a HNO3 solution followed by treatment with NH3). The obtained carbons were characterized by XRD, the low-temperature adsorption of nitrogen, SEM, TGA, and XPS in order to determine degree of graphitization, porosity, shape and size of particles, and surface composition, respectively. Finally, the materials were tested in phenol adsorption. The pseudo-second order model perfectly described the adsorption kinetics. A clear correlation between the micropore volume and the adsorption capacity was found. The content of graphite domains also had a positive effect on the adsorption properties. On the other hand, the presence of heteroatoms, especially oxygen groups, resulted in the clogging of the pores and a decrease in the amount of adsorbed phenol.

scholarly journals Isoterma dan Termodinamika Adsorpsi Kation Cu2+ Fasa Berair pada Lempung Cengar Terpilar

2012 ◽  
Vol 14 (1) ◽  
pp. 7
Author(s):  
Syaiful Bahri ◽  
Muhdarina Muhdarina ◽  
Nurhayati Nurhayati ◽  
Fitri Andiyani
Keyword(s):  
Gibbs Energy ◽  
Sodium Acetate ◽  
Atmospheric Condition ◽  
Freundlich Isotherm ◽  
Pillared Clays ◽  
Basal Spacing ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Clay Suspension ◽  
X Ray

Pillared Cengar clay have been synthesized by two methods, first clay suspension is directly mixed into aqueous solution of hydroxy-aluminum polycations (WK) and second by mixing the clay suspension into the solution of sodium acetate and hydroxy-aluminumpolycations (SAK) sequentially. Both clays were calcined in air on atmospheric condition. Diffraction pola, surface morphology and cationexchange capacity of the pillared clays were characterized using X Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) andvisible spectrophotometry methods, respectively. The pillared clays showed increases of basal spacing from 3.57 Å to 4.55 Å and smectiteas a new mineral. Morphology of SAK has more heterogeneous surface with small plates and agglomeration of grains compare with WKwhich small plates. Adsorption of aqueous cation of Cu 2+ were studied on various variables of initial concentration as well as temperatures.As the result, adsorption of cation Cu 2+ on pillared Cengar clay is corresponding to Freundlich isotherm, while the adsorption capacity ofWK on cation Cu 2+ is slightly lower than SAK. The thermodynamic aspect, the WK is reflected possessed exothermic processes withnegative entropy, increased in Gibbs energy and non spontaneous, while the SAK possessed endothermic processes having positive entropy,decreased in Gibbs energy and non spontaneous.

scholarly journals Aluminum Pillared Clay (Al-PILC) for Adsorption of Dyes in Red Fruit Oil

2021 ◽  
Vol 24 (1) ◽  
pp. 9-14
Author(s):  
Sholihah Novitasari ◽  
Sriatun Sriatun ◽  
Taslimah Taslimah
Keyword(s):  
Average Pore Size ◽  
Pillared Clay ◽  
Absorption Capacity ◽  
Heavy Fraction ◽  
Light Fraction ◽  
Basal Spacing ◽  
Average Pore ◽  
Type Iv ◽  
Dark Orange ◽  
Fruit Oil

Red fruit oil contains carotene, which is dark orange, so it is not very popular. Therefore, it is necessary to reduce the intensity of the color. Yesterday, in this study, the synthesis and characterization of Al-pillared clay (Al-PILC) from light and heavy clay fractions were carried out. The absorption capacity of red fruit carotene dyes was studied. The research stages included preparation, fractionation, activation, pillarization of clay with aluminum, characterization, and adsorption test for carotene dyes on red fruit. Characterization was carried out using X-ray Diffractometer (XRD) and Gas Sorption Analyzer (GSA). The results showed that basal spacing of natural clay, Al pillared heavy fraction-clay, Al pillared light fraction-clay, activated light fraction were 15.08 Å, 15.27 Å, 16.84 Å, and 16, respectively. 22 Å. The GSA results showed that the surface area and pore volume of the Al pillared light fraction-clay of 0.3 was higher than the heavy fraction. The average pore size of Al pillared light fraction-clay and the heavy fraction was found in the mesoporous range of 30-100 Å, and the adsorption isotherm is type IV. Al-pillared light fraction-clay had higher adsorption ability than a heavy fraction and light fraction before pillaring. When the pillaring agent’s concentration was 0.3 M, Al pillared heavy fraction-has absorption capacity is 58.66%, while Al pillared light fraction-clay is 90.4%.

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 Preparation and Characterization of Immobilized Molybdenum Complex on Pillared Montmorillonite K-10

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Farah Wahida Harun ◽  
Siti Balkis Mahamat Nor ◽  
Siti Salhah Othman
Keyword(s):  
Structural Characteristics ◽  
Xrd Analysis ◽  
Attenuated Total Reflection ◽  
Basal Spacing ◽  
Molybdenum Complex ◽  
X Ray ◽  
Pillared Montmorillonite ◽  
Sem Micrograph ◽  
Pillaring Solution

This study was carried out to immobilize molybdenyl (VI) acetylacetonate (MoO2(acac)2) complex on alumina pillared montmorillonite K-10 (MMT K-10). Pillar MMT K-10 was produced by introducing MMT K-10 with a hydrolysis solution of NaOH with AlCl3. Different concentrations of pillaring solution were prepared in terms of OHto Al3+ ratio (0.5, 1.0, 1.5 and 2.0) to observe the structural characteristics of MMT K-10. The pillared materials were then immobilized with 0.1 M MoO2(acac)2 and were characterized using X-ray diffractometry (XRD), scanning electron microscopy coupled in an energy dispersive X-ray spectrometer (SEM-EDX) and Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR) techniques. FTIR bands at ca. 890 – 930 cm-1 indicate that the Mo complex was immobilized on the surface of pillared MMT K-10 not in between the layers. This is supported by the SEM and XRD analysis where the SEM micrograph showed deposition of Mo on the surface of MMT K-10 as well as no modification of basal spacing was observed by XRD. Meanwhile, the d(001) spacing of the alumina pillared MMT K10 samples were seen to increase slightly as the concentration of OH/Al3+ increased.

Hydrothermal Synthesis and Phase Formation Mechanism of TiO2(B) Nanorods via Alkali Metal Titanate Phase Transformation

2018 ◽  
Vol 283 ◽  
pp. 23-36 ◽  
Author(s):  
Yothin Chimupala ◽  
Rik Drummond-Brydson
Keyword(s):  
Phase Transformation ◽  
Intermediate Product ◽  
Intermediate Phase ◽  
Metastable Phase ◽  
Exchange Process ◽  
Titanium Isopropoxide ◽  
Growth Direction ◽  
Proton Exchange ◽  
Transformation Mechanism ◽  
Synthesis Conditions

Titanium dioxide (B phase) with 1-D structures was successfully fabricated via a hydrothermal method with a subsequent ion-exchange process and calcination. P25, titanium isopropoxide (TTIP), rutile and also anatase were used as Ti precursors in the alkali hydrothermal system. TTIP promoted an elongation of nanorod morphology whereas the other precursors produced short nanorod structures. The different types of titanium precursors did not have any influence on the phase transformation during the fabrication process. Na2Ti6O13 was the primary intermediate product after washing the hydrothermal sample. H2Ti3O7 was the secondary intermediate phase obtained following proton-exchange of Na2Ti6O13 in HNO3 solution. Finally, the TiO2(B) phase was the product of calcination of the secondary intermediate product at 400°C for 5 hr. A phase transformation mechanism is presented based on an investigation of products at each of the steps. The effects of the synthesis conditions on tailoring of the crystal morphology are discussed. The growth direction of the TiO2(B) nanorods was investigated by HR-TEM and SADP. Finally, the metastable phase of TiO2(B) was shown to be transformed to anatase during thermal treatment at temperatures higher than 400°C.

Application of the Atomic Absorption Technical to Available the Concentration of Silver Ions Incorporated in Glass Matrix by Ionic Exchange Process

2010 ◽  
Vol 660-661 ◽  
pp. 873-878
Author(s):  
Elton Mendes ◽  
K.F. Silva ◽  
A. Teixeira ◽  
Luciano Silva ◽  
M.M.S. Paula ◽  
...  
Keyword(s):  
Atomic Absorption ◽  
Glass Matrix ◽  
Exchange Process ◽  
Silver Ions ◽  
Ion Concentration ◽  
Ionic Exchange ◽  
X Ray ◽  
Natural Clays ◽  
Comparative Results ◽  
Exchange Parameters

Ion specimens can be incorporated in glasses or natural clays by ionic exchange process with different concentrations dependent of matrix´s type and of the ionic exchange parameters. In particular, the incorporation of silver ions presents high interest by its biocidal properties. A compound contending ion silver specimens presents bactericidal and fungicidal properties with effect proportional to ion concentration. This work presents results about application of the atomic absorption technical to determine the silver ion concentration incorporated in a glass matrix by ionic exchange process. The ionic exchange experiments were realized with different AgNO3 concentration and constant temperature. After ionic exchange process, the glass samples were submitted to characterization by Energy Dispersive X-Ray Spectroscopy and Atomic Absorption Techniques. The comparative results between different techniques showed that atomic absorption technical is adequate to determine ion silver concentration incorporated in the glass matrix after ionic exchange process.

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