Clay samples

Digestion of clay samples with perchloric acid led to 3 explosions, each of which destroyed a ceramic hotplate used as heat source. There seems a good case for using metal hotplates for reactions involving risk of explosion. 

Taking this one step further, perhaps even an inorganic gene may have been provided by clay mineral sources. Earliest clay samples are of a mineral called montmorillonite that consists of sheets of aluminosilicates in which Fe2+, Fe3+ and Mg2+ are substituted for some of the Al3+, and Al3+ is substituted for Si4+. The oxygen content of the layers does not change and the alternative valencies allow the production of positive and negatively charged layers. Dramatically, Paecht-Horowitz and co-workers showed that the amino acid adenylate could be polymerised with up to 50 units on the montmorillonite surface in aqueous solution. Similar condensation reactions for carbohydrates on hydrotalcite surfaces have... 

Determination of the Chemical Formulae of Clay Samples using EDX Analysis... 

Table 2 gives the compositions of the same four clay samples in atomic percent. The atomic percent is defined as the number of atoms of an element per unit volume divided by the number of atoms per unit volume of the substance containing the element. This is similar to mole fraction when the atomic percent is converted to fractional value. 

Petrologic and SEM analyses of these clay samples reveal micro-textural and structural features and mineral association suggesting that they deposited directly from the brine in the surface facilities, and are not hydrothermal alteration minerals transported from production wells. 

Aragon, G.M. 2006. Determining the chemical formulae of clay samples from the Mindanao geothermal production field, Philippines. PNOC-EDC internal report. 

Observations of the same clay sample in a very finer scale (500 nm) by TEM, may help to identify the potential Fe-oxyhydroxide surfaces attached on a sediment grain (Fig.6). Moreover, abundances of wide spread oxides that may have formed oxide minerals after binding with other elements such as Si, Fe and Al can easily be recognized from the right part of the TEM image (Fig. 7). 

Clay samples were collected at areas of high-redox gradient at the edge of the Thorn-north ring and the Bean ring, which are H2S sourced and methane sourced, respectively. These samples were preserved under anoxic conditions and... 

To simplify terminology of axial systems, gzz is defined to be g(l (the g-value observed with the symmetry axis of Cu + parallel to the applied field), and gxx (= gyy) is defined to be gA (the g-value observed with the symmetry axis perpendicular to the applied field). An elongated z-axis (depicted in Figure 11 for Cu(H20)5 +) results in gjj > gj. For axially symmetric Cu + rigidly bound in a crystal, the g-value can then vary between the minimum (gj.) and maximum (g(,), depending on orientation of the crystal within the magnetic field. However, for axial Cu + bound in a powdered clay sample, all possible orientations, and therefore all g-values between gA and gj are represented in the "powder" spectrum. Therefore, electron spin resonance occurs only for field values, H, between Hjj and H, where ... 

The ilhte sample was supplied from Marmara region (Qanakkale, Can) in Tiukey for ceramic industries. The clay samples air dried and sieved from 425 pm sieve. Chemical composition of the clay samples were determined by X-ray diffraction. The results are given in Table 20.1. 

Natural clay samples were heated from 110°C to 900°C for 1 hour to obtain thermal achvated clay samples. Then samples put in a desiccator containing dried silica gel. Adsorphon experiments were carried out in a cylindrical vessel (2.4 L). The constant inihal concentrations of 800-920 mg/L of engine oil (SAE 40) were dispersed in 250 mL drinking water by stirring for 5 minutes (synthehcally wastewater). Mixing... 

N natural clay sample TA thermal activated clay sample... 

The studies relating the effect of temperature on adsorption was carried out at eight different temperatures (natural illite clay, 110°C, 200°C, 350°C, 450°C, 550°C, 750°C, 900°C) with a oil-grease concentration of 1,000 mg L and 5 g of illite clay sample, keeping the other parameters constants. Figure 20.2 shows oil-grease adsorption as a function of temperature. 

Fig. 12. Electron spin resonance spectra recorded at X-band for powdered clay samples at ambient laboratory temperature (a) montmorillonite, (b) kaolin, (c) Bentonite (Aldrich Chemical), (d) Bentonite (SSP/NF), (e) Magnabrite, (f) Polargel, (g) Volclay, and (h) Fuller s Earth (68).

In this section we first describe the results of measurements made on fresh and aged solutions. Potentlometric, pH, measurements, which Indicate the extent of hydrolysis of the aluminum Ions, were made on all solutions during the aging process. Next, we report surface areas of pillared clays made from the aged solutions. Finally, we will discuss the cracking activities of some selected pillared clay samples. 

A number of environmental applications [3] have been performed in order to size characterize colloids collected in rivers (riverbome particles, SPM, and sediments), clay samples and ground limestone (from soils), coal particles, diesel soot particles (from combustion processes), or airborne particles in urban areas (from waste incinerators, vehicles, household-heating systems, and manufacturing). In many of these cases, not only the size but also the particle size distribution was important and thus, in conjunction with the traditional UV detector, specific detectors such as ETAAS, ICP-MS, ICP-AES were used [40] in order to obtain more detailed, more specific compositional information. 

The Beta-zeolite catalyst samples were purchased from PQ Corporation and from UOP. The HF-treated p-zeolite and montmorillonite clay samples were prepared as described previously (9,12). 

In clay samples Zr-Th-rich coffinite was found around remnants of zircon. It is likely that it is the result of solid solution with zircon, ZrSi04 and thorite, ThSi04, which are isostruc-tural with coffinite (Finch Murakami 1999 Jensen Ewing 2001). The presence of phosphorus and sulphur in coffinite suggests that both elements substituted for Si in the coffinite structure. A previous study at the Bangombe site in Gabon has clearly shown that coffinites are most important secondary minerals for the retention of fissiogenic lanthanides and actinides (Stille et al. 2003). 

Fig. 2. Isosteric heat curves for the adsorption of water on two similar mont-morillonite clay samples. (A) From heat-of-immersion data of Ref. SO (B) From adsorption data of Ref. St.

The principal rubidium salts which would probably have been present in the sediment (chloride, sulfate, bicarbonate, etc.) are all soluble in water. As discussed later, the red clay was thoroughly dialyzed prior to use (including prior to analysis by emission spectroscopy). Any rubidium salts initially present in the clay samples would, therefore, have been removed by the dialyzing solution. Hence, it was assumed that the rubidium concentration given in Table I represented sorbed rubidium which had been in equilibrium with the rubidium in the original interstitial seawater. Then when calculating distribution coefficients from experimental data, the concentration given in Table I was used as the initial clay-phase rubidium concentration, rather than zero as used with most of the other species studied. 

Purification and Preparation of Clay Samples. The sand fraction of the clay samples was separated by slow-speed centrifugation of a suspension of the clay before the purification steps. 

Most of the clay samples were pre-equilibrated with the aqueous media to be used in the adsorption measurements to insure attaining the specified pH, usually 5, maintained with acetate buffer. 

Cation Exchange Capacity. Various techniques have been used to measure the cation exchange capacity of the clay samples. Unless otherwise noted, in computation of equilibrium quotients, we shall use a value of 0.78 equivalents/kg clay, determined by a column method (14) on the calcium form of Wyoming montmoril-lonite at pH 5. 

Figure 10a. Adsorption of Ca(II) on the sodium form of Wyoming montmorillonite (Loading trace —1.4 X 10 mol Ca(ll)/kg, pH 5, equilibration for 18 hr.) Clay samples from Jacksons purification procedure ( ), NaCl + O.OIM NaOAc M, NaCl + O.IM NaOAc. Clay sarnies from Dowex column ( ), NaCl + O.IM NaOAc.

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