Chlorite determination

Electron micrographs showed the formation of metallic cobalt particles (ca 100A), supported on the remnants of the clay after calcination and reduction (Figure 4). In part, the degree of chloritization determined the extent of formation of free Co O from the clay and, correspondingly, the amount of Co metal present in the samples was found to reach a maximum at Al/Al+Si of 0.2-0.3. Furthermore, only a fraction of the Co present in these clays was reduced and available for catalytic reaction. The remaining Co was contained within the 2 1 layer clay framework and remained unreduced until >700 C, a temperature typical of that needed to initiate total framework collapse. 

Chlorous Acid. The physical properties of HCIO2 have been determined using acidified alkah metal chlorite solutions. The existence of HCIO2 is based on spectroscopic evidence (6,13,97). 

Chlorous Acid. The chemical piopeifies of HCIO2 have been determined from the acidification of alkah metal chlorites. The acid... 

Note. Hypochlorites and chlorites may be reduced to chlorides with sulphur dioxide, and determined in the same way. 

Since temperature, /s, and iron content of chlorite were determined (section 2.4.2), we can estimate /hjS range from the following reaction ... 

The Mg content of hydrothermally altered volcanic rocks is reflected by the extent of seawater-volcanic rock interaction at elevated temperatures, because it has been experimentally and thermodynamically determined that nearly all of the Mg in seawater transfer to volcanic rocks, owing to the reaction of the cycled seawater with volcanic rocks at elevated temperatures (Bischoff and Dickson, 1975 Mottl and Holland, 1978 Wolery, 1979 Hajash and Chandler, 1981 Reed, 1983 Seyfried, 1987). It has been shown that the CaO content of hydrothermally altered midoceanic ridge basalt is inversely correlated with the MgO content with a slope of approximately — 1 on a molar basis (Mottl, 1983). This indicates that Ca of basalt is removed to seawater and Mg is taken up from seawater by the formation of chlorite and smectite during the seawater-basalt interaction. This type of reaction is simply written as ... 

The concentration of chlorine dioxide, chlorite and total oxidants was determined on site using a portable colorimeter (Palintest Photometer 5000) and a modification of the DPD test in which any chlorine species are complexed with glycine to ensure only chlorine dioxide reacts with DPD. The chlorite and total oxidants are then determined on a fresh sample by acidification and neutralisation in the presence of potassium iodide. The initial dose level was set at 0.3ppm chlorine dioxide injected in the water feed to the cold... 

Impact sensitivities of mixtures of red phosphorus with various oxidants were determined in a direct drop-ball method, which indicated higher sensitivities than those determined with an indirect striker mechanism. Mixtures with silver chlorate were most sensitive, those with bromates, chlorates and chlorites were extremely sensitive, and mixtures with sodium peroxide and potassium superoxide were more sensitive than those with barium, calcium, magnesium, strontium or zinc peroxides. Mixtures with perchlorates or iodates had sensitivities comparable to those of unmixed explosives, such as lead azide, 3,5-dinitrobenzenediazonium-2-oxide etc. 

With XPS it is possible to obtain good analytical information on the amount of metal adsorbed and, in favourable cases, to identify the chemical form of that metal. Oxidation states are readily determined and it can be shown, for example, that adsorption of Co(II) on manganese oxides results in oxidation to Co(III) (38,39), whereas adsorption of Co(II) on zirconia and alumina leads to the formation of cobalt(II) hydroxide (40). With Y-type zeolites hexaaquacobalt(II) is adsorbed as Co(II), and cobalt(III) hexaammlne is adsorbed as Co(III). The XPS spectrum of Co(II) adsorbed on chlorite was consistent with the presence of the hexaaquacobalt(II) ion for pH 3-7 and indicated that no cobalt(II) hydroxide was present (41). With kaollnlte and llllte, Co is adsorbed as Co(II) over the pH range 3-10 (39,42), it being bound as the aqua ion below pH 6 and as the hydroxide above pH 8. Measurements involving Pb have... 

This information is reported as the percentage that each of the clay mineral type contributes to total identifiable clay mineral content of the noncarbonate clay-sized fraction of the surface sediments. These percentages were determined by x-ray diffraction, which is luiable to identify noncrystalline solids. Using this technique, clay minerals were found to comprise about 60% of the mass of carbonate-free fine-grained fraction. Most of the noncrystalline soUds are probably mixed-layer clay minerals. Carbonate was removed to facilitate the x-ray diffraction characterization of the clay minerals. In some cases, roimd off errors cause the sum of the percentages of kaolinite, illite, montmorillonite, and chlorite to deviate slightly from 100%. 

Determination of Chlorine Dioxide and Chlorite Ion in Drinking Water using Lissamine Green B and Horseradish... 

The bedrock source of the 10s to 100s of Cr-diopside grains in tiii across the region has not yet been found, in spite of the predominance of pyroxenites and peridotites in the TNB, remnants of primary Cr-diopside are scarce because most rocks have been metamorphicaiiy and metasomaticaiiy aitered such that serpentine has repiaced oiivine and orthopyroxene and amphiboie, chlorite, talc and carbonate has replaced clinopyroxene. Be-cause the Cr-diopside source is unknown, their compositional range and relationship to Ni-mineralization cannot be determined. 

Analytical Methods for Determining Chlorine Dioxide and Chlorite in Environmental... 

If you are exposed to chlorine dioxide and chlorite, many factors determine whether you ll be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with them. You must also consider the other chemicals you re exposed to and your age, sex, diet, family traits, lifestyle, and state of health. 

IS THERE A MEDICAL TEST TO DETERMINE WHETHER I HAVE BEEN EXPOSED TO CHLORINE DIOXIDE AND CHLORITE ... 

Although no medical tests are available to determine whether you have been exposed to chlorine dioxide or chlorite, exposure to very large amounts may result in damage to red blood cells that may be observed through routine blood tests. 

Section 104(I)(5) of CERCLA, as amended, directs the Administrator of ATSDR (in consultation with the Administrator of EPA and agencies and programs of the Public Health Service) to assess whether adequate information on the health effects of chlorine dioxide and chlorite is available. Where adequate information is not available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the initiation of a program of research designed to determine the health effects (and techniques for developing methods to determine such health effects) of chlorine dioxide and chlorite. 

No methods for determining chlorine dioxide in biological materials were located. Most studies concerning human health effects measure the concentrations of chlorine dioxide in the air or in water. The measurement of chlorine dioxide in biological materials is not commonly used because of the rapid conversion of chlorine dioxide to chlorine-containing metabolites, such as chlorite and chloride ions. 

The concentration of residual chlorite ion in vegetables and eggs treated with sodium chlorite was determined by UV-ion chromatography (Suzuki et al. 1997). Sodium chlorite was extracted with water and cleaned-up using Cl 8 cartridge. The detection limit of sodium chlorite in vegetables and eggs was 1 mg/kg with recoveries of 90-100%. 

Beitler MK, Chin HB. 1995. Improved determination of chlorite and chlorate in rinse water from carrots and green beans by liquid chromatography and amperometric and conductivity detection. J AO AC Int 78(3) 878-883. 

Denis M, Minon G, Masschelein WJ. 1989. Continuous determination of residual chlorite in water. Anal ChimActa 226(1) 121-128. 

Dietrich AM, Ledder TD, Gallagher DL, et al. 1992. Determination of chlorite and chlorate in chlorinated and chloraminated drinking water by flow injection analysis and ion chromatography. Anal Chem 64 498-502. 

Kim J, Marshall MR, Du WX, et al. 1999. Determination of chlorate and chlorite and mutagenicity of seafood treated with aqueous chlorine dioxide. J Agric Food Chem 47 3586-3591. 

Suzuki J, Okumoto C, Katsuki Y, et al. 1997. Determination of residual chlorite in vegetables and eggs treated with sodium chlorite by UV-ion chromatography and effect of soaking in water. J Food Hyg Soc Jpn 38(l) 22-26. 

One last point. In the reaction of uranium(IV) where it is convenient to do a tracer experiment because there is only one metal ion product, we have actually determined the number of oxygens transferred to the uranyl ion product from the chlorite, and this number corresponds to 1.3 oxygen per chlorite transferred to the uranium. This is consistent with the results we reported some years ago (5) on the oxidation of uranium (IV) with Pb02 and Mn02, where indeed more than one oxygen is transferred. In conclusion, we feel that we have some direct evidence for two-electron transfer in these reactions and the formation of a chlorine(I) intermediate followed by the formation of chlorate. 

It is clear from the figures that these chlorites are usually richer in silica, than berthierines or magnesian 7 X synthetic minerals. The compositions are quite variable (1 5 ionic percent Si or Al), but nevertheless the compositions determined from grain to grain in one sample do not exceed the limits defined for synthetic 14 X chlorites (Velde, 1973). 

This has been confirmed in the present study for chlorites from six rocks from the Belt series in northern Montana (Harrison and Jobin, 1963) and three samples from the outer zones in the Alpine chain. From these analyses, it is apparent that metamorphic chlorites which have crystallized with muscovite have low silica contents and a rather limited alumina content (27 3% A1 ions). The relatively large variation in chlorite Fe-Mg ratio from rock to rock suggests that bulk rock composition is more important in determining the chlorite composition than is the case of chlorites from clay mineral facies. 

In the detailed mineralogical determinations made by Fontes, et al.. one fact is striking. Illite seems to persist until the most sepiolite-rich zones are attained, while kaolinite-chlorite are found only when neither sepiolite nor palygorskite are present. If we assume that illite remains stable because it is a potassic mineral (or dominantly so), it will exist as a phase supplementary to those found in Figure 41. The... 

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