نتایج جستجو برای: Palygorskite
تعداد نتایج: 265 فیلتر نتایج به سال:
Microfibrous palygorskite and tubular halloysite clay mineral combined with nanocrystalline TiO2 are incorporating in the preparation of nanocomposite films on glass substrates via sol-gel route at 450C. The synthesis is employing nonionic surfactant molecule as pore directing agent along with acetic acid-based sol-gel route without addition of water molecules. Drying and thermal treatment of c...
Similar to asbestos fibers, nonregulated mineral fibers can cause malignant mesothelioma (MM). Recently, increased proportions of women and young individuals with MM were identified in southern Nevada, suggesting that environmental exposure to carcinogenic fibers was causing the development of MM. Palygorskite, a fibrous silicate mineral with a history of possible carcinogenicity, is abundant i...
-The role of adsorbed and structural Fe n+ in palygorskite and sepiolite with respect to the oxidation of hydrocortisone in aqueous suspension has been evaluated using electron spin resonance and UVvisible spectroscopy. Natural surface-adsorbed Fe 3+ showed an important activity in the oxidation process, although smaller than octahedral Fe 3+. The kinetics of oxidative degradation of hydrocorti...
As the preliminary results of experimental studies on dust from the palygorskite group have led to some confusion a detailed description of the completed investigation is given for clarification. As in other experiments the biological effects have been shown to be associated with the physical characteristics of the fibres in these specimens. Samples of sepiolite and attapulgite from Spain and a...
Calcretes are the calcite crusts widely developed at the Earth's surface in semi-arid regions (e.g., Goudie, 1983; Nahon, 1991; Wright and Tucker, 1991 ). Thickness of calcretes is tens of centimeters to a few meters, and increases downslope. Calcretes pseudomorphically replace all underlying silicate rocks. Parent rock structure and bulk volume are preserved. In the lower part of calcrete prof...
physical behavior of wetted soils is of paramount importance. The rheology of aqueous suspensions of six palygorskites with When the electrolyte concentration in the percolating different particle morphologies has been investigated as a function solution in soil is below the flocculation value of the of clay concentration, adsorbed ion, pH, and electrolyte concentration, clay, clay dispersion o...
Formation of clay minerals is affected by soil forming factors which in turn play an important role in soil management. The aim of the present research was to study genesis, classification, and clay mineralogy of Koshkooiyeh-Anar soils. Four representative pedons were studied for physicochemical and clay mineralogy analyses. Gypsic, salic, and natric were among the diagnostic horizons that have...
Clay minerals deserve special attention as they play a crucial role in many soils. The clay mineralogy of five gypsiferous soils from different landforms in eastern Isfahan was investigated using X-ray diffraction (XRD). In addition, soil aggregates and wind-deposited sediments were examined by scanning electron microscope (SEM) and analyzed by energy dispersive X-ray analyzer (EDX). The resul...
Clay minerals deserve special attention as they play a crucial role in many soils. The clay mineralogy of five gypsiferous soils from different landforms in eastern Isfahan was investigated using X-ray diffraction (XRD). In addition, soil aggregates and wind-deposited sediments were examined by scanning electron microscope (SEM) and analyzed by energy dispersive X-ray analyzer (EDX). The resul...
Palygorskite, a fibrous clay mineral, is being used as a substitute for asbestos in some applications. Nine specimens obtained from different geological locales were studied for mineral purity, elemental composition, fibre size distribution, and surface binding characteristics. The membranolytic activity of each was determined using a human erythrocyte model. The membranolytic behaviour and sur...
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