Characterization of Egyptian kaolins for health-care uses

Awad, Mahmoud E.; López-Galindo, Alberto; El-Rahmany, Mahmoud M.; El-Desoky, Hatem M.; Viseras, César

doi:10.1016/j.clay.2016.09.018

Cited by 28 publications

(29 citation statements)

References 35 publications

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“…Samples N-2, K-3, F-2 and D-6 were highly pure, with kaolinite contents of 99%, 95%, 98% and 98%, respectively. The Al 2 O 3 /SiO 2 ratios of the bulk kaolin samples were found very close to the stoichiometric ratio (0.85) of the theoretical kaolinite, except in sample K-3 which was slightly influenced by the illite content [38]. Mineral impurities, especially the quartz contents, were detected as traces, which comply with the safety limits of human toxicological specifications ( Figure 2 and Table 1, [58]).…”

Section: Compostion and Microstructuresupporting

confidence: 62%

“…Four representative high-grade (i.e., high purity and quality) raw kaolinite-rich samples (named N-2, F-2, D-6 and K-3) with variable structural ordered-disordered degrees were selected for testing and evaluation of their tableting characteristics and powder flowability. These samples belong to the economically viable Egyptian Abu Zenima kaolin deposits, characterized mineralogically, chemically and proved suitability for pharmaceutical uses according to specifications and limits reported in kaolin monograph of the European and US Pharmacopoeias and the European Medicines Agency [38].…”

Section: Materials and Preparationmentioning

confidence: 99%

“…The purified kaolin samples were analyzed by means of X-ray diffraction (XRD) and X-ray fluorescence (XRF) by following the same methods described in Awad et al [38]. The XRD analysis was performed by using an X'Pert Pro diffractometer (CuKα radiation, 45 kV, 40 mA, Malvern PANalytical Ltd, Malvern, UK) equipped with an X'Celerator solid-state linear detector (Malvern PANalytical Ltd, Malvern, UK), using a step increment of 0.008 • 2θ and a counting time of 10 s/step.…”

Section: Xrd/xrf Composition and Microstructurementioning

confidence: 99%

“…In high purity kaolin grade, the most variable and modifiable technological properties that generally control the applicability and quality of kaolinite as excipient material in pharmaceutical solid and semisolid formulations are the structural, micromorphological and microtextural characteristics [35][36][37], particularly the kaolinite platelets stacking order-disorder degree and its average coherent thickness, i.e., crystallite size, porosity, particle shape, particle-particle interaction and packing pattern, particle size granulometry and the uniformity or heterogeneous grading character of the kaolin powder [38,39]. Therefore, flowability properties are high probably influenced by these powder characteristics, which could affect the performance and efficiency of tablets manufacturing and their physical and physicochemical stability during storage.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, only the halloysite tableting properties, amongst all the clay minerals, were recently characterized by means of this method [41]. The kaolinite resources of Abu Zenima district, located at west central Sinai in Egypt (estimated at 120 million tons), have recently received attention for evaluation and exploitation in pharmaceutical uses [38]. In the present study, the tableting properties of some representative high grade samples of Egyptian kaolins have been characterized by powder compaction analysis following the method of Osamura et al [42] for evaluating their potentiality and performance as pharmaceutical excipient, checking the effects of their particle micrometrics and powder geometrical characteristics as quality controlling factors on the tableting properties.…”

Section: Introductionmentioning

confidence: 99%

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Flow and Tableting Behaviors of Some Egyptian Kaolin Powders as Potential Pharmaceutical Excipients

et al. 2019

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The present work aimed at assessing the pharmaceutical tableting properties of some Egyptian kaolin samples belong to the Abu Zenima kaolin deposits (estimated at 120 million tons). Four representative samples were selected based on kaolinite richness and their structural order-disorder degree, and after purification, they were dried at 70 • C and heated from room temperature up to 400 • C (10 • C/min). Mineralogy, micromorphology, microtexture, granulometry, porosimetry, moisture content, bulk and tapped density, direct and indirect flowability, and tableting characteristics are studied. Results indicated that purified kaolin samples were made up of 95-99% kaolinite, <3% illite, 1% quartz and 1% anatase. The powder showed mesoporous character (pore diameters from 2 to 38 nm and total pore volume from 0.064 to 0.136 cm 3 /g) with dominance of fine nanosized particles (<1 µm-10 nm). The powder flow characteristics of both the ordered (Hinckley Index HI > 0.7, crystallite size D001 > 30 nm) and disordered (HI < 0.7, D001 < 30 nm) kaolinite-rich samples have been improved (Hausner ratio between 1.24 and 1.09) as their densities were influenced by thermal treatment (with some observed changes in the kaolinite XRD reflection profiles) and by moisture content (variable between 2.98% and 5.82%). The obtained tablets exhibited hardness between 33 and 44 N only from the dehydrated powders at 400 • C, with elastic recovery (ER) between 21.74% and 25.61%, ejection stress (ES) between 7.85 and 11.45 MPa and tensile fracture stress (TFS) between 1.85 and 2.32 MPa, which are strongly correlated with crystallinity (HI) and flowability (HR) parameters. These findings on quality indicators showed the promising pharmaceutical tabletability of the studied Egyptian kaolin powders and the optimization factors for their manufacturability and compactability.

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Section: Compostion and Microstructuresupporting

confidence: 62%

Section: Materials and Preparationmentioning

confidence: 99%

Section: Xrd/xrf Composition and Microstructurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Flow and Tableting Behaviors of Some Egyptian Kaolin Powders as Potential Pharmaceutical Excipients

et al. 2019

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Photocatalytic degradation of Rhodamine B dye using low‐cost pyrofabricated titanium dioxide quantum dots‐kaolinite nanocomposite

Awad

Farrag

El-Bindary

et al. 2023

Applied Organom Chemis

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In this study, we report a simple technique for the pyrofabrication of a novel photocatalyst of titanium dioxide quantum dots-kaolinite nanocomposite (TiO 2 -QDs-Kao) used for rhodamine B (RhB) dye degradation. The photocatalyst was characterized by using different analytical techniques, including XRD, XRF, XPS, FTIR, DTA/TGA, SEM-EDX, TEM, BET, BJH, ZP and UV-Vis DRS. The photocatalytic degradation of RhB was performed in aqueous solutions using the sustainable sunlight energy under atmospheric conditions and fixed neutral medium (pH = 7). The produced photocatalyst exhibited optical band gap energy of 2.85 eV, an improved large specific surface area of 107.724 m 2 /g with pore radius of 1.45 nm and total pore volume of 0.123 cm 3 /g.The study indicated a maximum 91% degradation efficiency of RhB after 120 min using the optimum dose 1,400 mg/l of the TiO 2 -QDs-Kao photocatalyst. The degradation of RhB dye fitted the Langmuir first-order kinetics with rate constant 0.0151 min À1 . The radical trapping experiments based on scavengers confirmed that the mechanism of photocatalytic degradation activity was potentially based on electron (e À ) and hole (h + ) conduction band. The potential energy of the valence and conduction bands E VB and E CB were calculated 2.73 and À0.12 eV, respectively. A triple reusability study confirmed a high stability of TiO 2 -QDs-Kao photocatalyst with detected degradation efficiencies of 91.0, 89.9, 88.8 and 87.5%, respectively.

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Optimization of Photocatalytic Degradation of Rhodamine B and Indigo Carmine Dyes Using Eco‐Friendly Kaolinite‐Silver Oxide Quantum Dots Nanocomposite Under Sunlight Irradiation

Awad,

Farrag,

Aboelnga

et al. 2024

Applied Organom Chemis

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In this work, we present a simple method for the pyrofabrication of a new kaolinite‐ silver oxide quantum dots nanocomposite (Kao‐Ag2O/QDs) that is used for the degradation of rhodamine B (RhB) and indigo carmine (IC) dyes. A homogenous combination of kaolinite and silver nitrate was sintered up to 350 °C to create the extremely effective photocatalyst (Kao‐Ag2O/QDs). Various analytical techniques were employed to characterize the Kao‐Ag2O/QDs photocatalyst such as XRD, FTIR, XPS, SEM–EDX, TEM, DTA/TGA, ZP, BET, and UV–Vis DRS. The degradation of RhB and IC dyes through the photocatalyst was carried out in aqueous solutions utilizing several pH dye solutions and sustainable solar energy in atmosphere conditions. The nanocomposite that was prepared had shown an enhanced specific surface area of 53.3005 m2/g, a pore size of 8.1197 nm, and a total pore volume of 0.216 cm3/g. It also displayed an optical band gap energy of 2.9 eV. The study creates that employing the ideal dose of 2000 and 1500 mg/L of the Kao‐Ag2O/QDs photocatalyst at neutral conditions (pH = 7) resulted a maximum degradation effectiveness of RhB and IC of 91.06 and 93.46% after 90 min, respectively. RhB and IC dyes degradation followed Langmuir first‐order kinetics with a rate constant of 0.0217 and 0.0216 min−1 at pH = 7, respectively. The photocatalytic degradation activity for RhB dye is based on hydroxyl radicals (˙OH) and superoxide radicals (˙O2−), while the mechanism of IC removal is based on superoxide radicals (˙O2−), as revealed by scavenger‐based radical trapping studies. A triple reusability study found that the Kao‐Ag2O photocatalyst is highly stable with degradation efficiencies of RhB and IC dyes from the initial 91.09 to 90.04, 88.54, and 86.27% and from the initial 93.46 to 92.8, 91.4 and 89.32%, respectively. The optimal situations for the parameters were identified by the Box–Behnken design (BBD), which was well matched with photocatalytic degradation tests.

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Characterization of Egyptian kaolins for health-care uses

Cited by 28 publications

References 35 publications

Flow and Tableting Behaviors of Some Egyptian Kaolin Powders as Potential Pharmaceutical Excipients

Flow and Tableting Behaviors of Some Egyptian Kaolin Powders as Potential Pharmaceutical Excipients

Photocatalytic degradation of Rhodamine B dye using low‐cost pyrofabricated titanium dioxide quantum dots‐kaolinite nanocomposite

Optimization of Photocatalytic Degradation of Rhodamine B and Indigo Carmine Dyes Using Eco‐Friendly Kaolinite‐Silver Oxide Quantum Dots Nanocomposite Under Sunlight Irradiation

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