Of methylene blue

One hundred milliliters of an aqueous solution of methylene blue contains 3.0 mg dye per liter and has an optical density (or molar absorbancy) of 0.60 at a certain wavelength. After the solution is equilibrated with 25 mg of a charcoal the supernatant has an optical density of 0.20. Estimate the specific surface area of the charcoal assuming that the molecular area of methylene blue is 197 A. ... 

Dye adsorption from solution may be used to estimate the surface area of a powdered solid. Suppose that if 3.0 g of a bone charcoal is equilibrated with 100 ml of initially 10 Af methylene blue, the final dye concentration is 0.3 x 10 Af, while if 6.0 g of bone charcoal had been used, the final concentration would have been 0.1 x Qr M. Assuming that the dye adsorption obeys the Langmuir equation, calculate the specific surface area of the bone charcoal in square meters per gram. Assume that the molecular area of methylene blue is 197 A. ... 

Brown and Lin reported a quantitative method for methanol based on its effect on the visible spectrum of methylene blue. In the absence of methanol, the visible spectrum for methylene blue shows two prominent absorption bands centered at approximately 610 nm and 660 nm, corresponding to the monomer and dimer, respectively. In the presence of methanol, the intensity of the dimer s absorption band decreases, and that of the monomer increases. For concentrations of methanol between 0 and 30% v/v, the ratio of the absorbance at 663 nm, Asss, to that at 610 nm, Asio, is a linear function of the amount of methanol. Using the following standardization data, determine the %v/v methanol in a sample for which Agio is 0.75 and Ag63 is 1.07. 

There are many colorimetric methods used for trace analysis of peroxides using reagents such as ferrous ion, leuco base of methylene blue, yy -diphenylcarbohydrazide, titanium(IV), iodide ion, and Ai,A7-dimethyl- -phenylenediamine. The latter two are the most commonly used reagents... 

Warm a few of the crystals with yellow ammonium sulphide solution for a few minutes, acidify with hydrochloric acid, und finally add a little feiric chloride. A deep blue colouration Ls produced, due to the formation of methylene blue. 

The methylene blue test can also be used to determine cation exchange capacity of clays and shales. In the test a weighed amount of clay is dispersed into water by a high-speed stirrer. Titration is carried out as for drilling muds, except that hydrogen peroxide is not added. The cation exchange capacity of clays is expressed as milliequivalents of methylene blue per 100 g of clay. 

The method developed by Epton [212,213] became the universally accepted method for the analysis of active matter of anionic and cationic surfactants. Epton s method, also known as the two-phase titration, is based on the titration of the anionic surfactant with cetylpyridinium bromide, a cationic surfactant, in the presence of methylene blue as indicator. A solution of the anionic surfactant is mixed with the indicator dissolved in dilute sulfuric acid, followed by further addition of chloroform, and then it is titrated with the cationic surfactant. Methylene blue forms a complex with the anionic salt that is soluble in chloroform, giving the layer a blue color. As the titration proceeds there is a slow transference of color to the water layer until the equivalence point. At the equivalence point colors of the chloroform and water layers are visually the same. On successive additions of titrant the chloroform layer lightens in shade and finally becomes colorless. 

Functional loss or loss of methylene blue active substance (MBAS) has been studied by Kravetz et al. [141]. These authors have shown 98-99% disappearance of AOS and AES starting materials by the third day of the study. It was also observed that LAS degrades at significantly slower rates than AOS in MBAS tests. 

Release of tetracycUne hydrochloride from PCL fibers was evaluated as a means of controlled administration to periodontal pockets (69). Only small amounts of the drug were released rapidly in vitro or in vivo, and poly(ethylene-co-vinyl acetate) gave superior results. Because Fickian diffusion of an ionic hydrochloride salt in a UpophiUc polymer is unlikely, and because PCL and EVA have essentially identical Fickian permeabilities, we attribute this result to leaching of the charged salt by a mechanism similar to release of proteins from EVA (73). Poly-e-caprolactone pellets have been found unsuitable for the release of methylene blue, another ionic species (74,75). In this case, blending PCL with polyvinyl alcohol (75% hydrolyzed) increased the release rate. 

FIGURE 8 Cumulative release of methylene blue (o), [1,4 - 14c] succinic acid (a), and polymer weight loss ( ) from polymer discs prepared from 3,9-bis(ethylidene-2,4,8,10-tetraoxaspiro[5,5Jundecane) and a 50 50 mole ratio of trans - cyclohexane dimethanol and 1,6-hexanediol at pH 7.4 and 37°C. Polymer contains 0.1 wt% [1,4 — [succinic anhydride and 0.3 wt% methylene blue. (From Ref. 

Butterman, M Tietz, D Orban, L Chrambach, A, Ferguson Plots Based on Absolute Mobilities in Polyarcylamide Gel Electrophoresis Dependence of Linearity of Polymerization Conditions and Application on the Determination of Free Mobility, Electrophoresis 9, 293, 1988. Caglio, S Chiari, M Righetti, PG, Gel Polymerization in Detergents Conversion Efficiency of Methylene Blue vs. Persulfate Catalysis, as Investigated by Capillary Zone Electrophoresis, Electrophoresis 15, 209, 1994. 

Cagho, S Righetti, PG, On the Efficiency of Methylene Blue versus Persulfate Catalysis of Polyacrylamide Gels, as Investigated by Capillary Zone Electrophoresis, Electrophoresis 14, 997, 1993. 

The blue dye (47), formed from the autoxidation of 4-/V,TV-di methyl-amino-2-hydroxyaniline, is the oxygen analogue of methylene blue. The autoxidation of 1,2,4-trihydroxybenzene, carried out in the presence of ammonia, gives the hydroxyphenoxazinone dye (48) via a 2,4-dihydroxyani-line intermediate (Scheme 17). Many types of phenoxazines, phenazines, and phenoxazinium salts can be obtained by autoxidation of polyhydroxyben-zenes and their amino derivatives. Some autoxidative dyes may give poly-... 

Minero C, Lucchiari M, Vione D, Maurino V (2005) Fe(III)-enhanced sonochemical degradation of methylene blue in aqueous solution. Environ Sci Technol 39(22) 8936-8942... 

Sometimes there is a significant difference in bulk and surface doping, as reported in the case of B and V co-doping, where improvement in the degradation of methylene blue was observed only when V was present at the surface of the photocatalyst [69]. 

Cr- and N-doped titania showed improved activity under visible light in the degradation of methylene blue and isopropyl alcohol [89]. I-doped Ti02 showed better activity than Degussa P25 for methylene blue degradation. The sample composed of anatase and rutile showed better activity than that with only anatase [90] for phenol degradation [91]. 

Bayati, M.R., Golestani-Fard, F., and Moshfegh, A.Z. (2010) Visible photodecomposition of methylene blue over micro arc oxidized WOj-loaded Ti02 nano-porous layers. Applied Catalysis A General, 382 (2), 322-331. 

The photocatalytic activity of ZnO nanomaterials for the degradation of some organic pollutants in water [173] (e.g., dyes [174]) was explored by several groups to achieve environmental benefits. Recent studies have indicated that ZnO can be used under acidic or alkaline conditions with the proper treatment [175,176]. ZnO nanomaterials were used as photocatalysts for the degradation of phenol [177] and chlorinated phenols such as 2,4,6-trichlorophenol [178]. ZnO nanomaterials were also used for the degradation of Methylene Blue [179], direct dyes [180], Acid Red [181], and Ethyl Violet [182],... 

Jang, Y.J., Simer, C. and Ohm, T. (2006) Comparison of zinc oxide nanoparticles and its nano-crystalline particles on the photocatalytic degradation of methylene blue. Materials Research Bulletin, 41,67-77. 

Mazmanci MA, Unyayar A, Ekiz HI (2002) Decolorization of Methylene Blue by White Rot Fungus Coriolus versicolor. Fresenius Environ Bull 11 5... 

Selenium Adsorption colloid flotation Spectrophotometry of methylene blue complex - [517,546]... 

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