نتایج جستجو برای: smectite
تعداد نتایج: 982 فیلتر نتایج به سال:
this study investigated the relationship between clay minerals and different soil moisture regimes in gypsiferous soils of fars province in southern iran. the overall climate of the province is arid and semi-arid and, under this condition, parent material is the most important factor affecting clay minerals distribution. beside this factor, climate conditions have determining role too. palygors...
Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, iron sulfides, amorphous material, and trioctahedral smectites. The John Klein smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. The C...
-Smectites synthesized from experiments at 5.5 GPa and 1500~ are of high quality, crystals are large at >10 p~m, and the 2:1 layers may have a homogeneous charge distribution. Smectite was exchanged with various cations (Na + , Li +, K +, Ca 2+, and Mg z+) and the hydration behavior of each sample was observed by an in situ powder X-ray diffraction method under precisely controlled relative hum...
Veins containing carbonates, hydrous silicates and sulphates that occur within and between grains of augite and olivine in the Nakhla meteorite are good evidence for the former presence of liquid water in the Martian crust. Aqueous solutions gained access to grain interiors via narrow fractures, and those fractures within olivine whose walls were oriented close to (001) were preferentially wide...
The mineralogy and chemistry of the less than 20μm fraction of marine sediments at Morphou Bay, north-west Cyprus, are presented to characterise fine-grained sediment supplies from basic and ultrabasic rocks of the Troodos Massif within a typological setting. The sediments comprise a mixture of smectite, illite, kaolinite and iron rich chlorite. They also contain amorphous iron oxides/hydroxide...
Cysteine and toluene as model organic molecules were intercalated into Fe-rich smectite (nontronile, NAu-2). The illitization of these intercalated smectites as induced by microbial reduction of structural Fe" was investigated. Iron-reducing bacterium Shewanellaputrefaciens CN32 was incubated with lactate as the sole electron donor and structural Fe* in cysteineand toluene-intercalated NAu-2 (r...
[1] The transformation of hydrated clay minerals (smectite) to anhydrous forms (illite) occurs in the diagenesis of shales in sedimentary basins. The released pore water can lead to excess pore pressures and is of concern in oil drilling operations. Most simply, the process can be modeled as a first-order thermally activated reaction, but an alternative interpretation is that diagenesis occurs ...
Abstraet--A method for the determination of the cations of Na, K, Mg and Ca adsorbed on clay minerals mixed with CaCO3 and MgCO3 is described. An ethanolic solution of LiC1-CsC1 is used to displace the exchangeable cations. Blank determinations performed using either a second ethanolic leach or a second LiC1-CsC1 leach, are used to correct for carbonate dissolution. Details of the methods devel...
A good material for CO2 capture should possess some specific properties: (i) a large effective surface area with good adsorption capacity, (ii) selectivity for CO2, (iii) regeneration capacity with minimum energy input, allowing reutilization of the material for CO2 adsorption, and (iv) low cost and high environmental friendliness. Smectite clays are layered nanoporous materials that may be goo...
The interaction of sulfonamide antimicrobial agents with smectite clay minerals and humic acid (HA)-clay complexes was investigated in batch experiments to assess the influence of adsorbed humic acid on sulfonamide sorption. Soil HA-clay complexes were produced at HA:clay ratios of 1:5, 1:50, and 1:100 (w/w). Vibrational and electronic spectroscopy indicated the preferential adsorption of polar...
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