Methylene Blue absorption test

Methylene Blue test can also be used to differentiate between oxycellulose and hydrocellulose. Methylene Blue is a cationic dye. Standard cellulose generally has no affinity for Methylene Blue, but oxycellulose with the formation of carboxyl groups confer an affinity and can be sorbed onto cotton. For this purpose. Methylene Blue absorption tests are carried out both at pH of 7.0 and at a pH of 2.7 (acidic). Two pieces of fabrics to be tested are taken and treated one with Methylene Blue at a pH of 2.7 and the other at pH 7.0. If oxycellulose is present, the material will absorb less dye in the acid than in the neutral solution, whilst reverse is the case if hydrocellulose is present. The degree of staining will indicate the extent of degradation. 

In another method, Ig cation free sample is treated with 100 ml of Methylene Blue solution (10 m. moles/1) buffered in presence of potassium dihydrogen phosphate (0.625 m. moles/1) andNaOH (0.4 m. moles/1). The contents of the flask are agitated for about 18 h at room temperature. The solution is poured off from the 

If a dyed material is under test, the stripping of dye will be necessary before the test can be carried out. Alternatively, degradation can be determined by titration using an anionic dye which precipitates Methylene Blue from solution. 

Scoured and bleached American cotton have carboxyl contents of 0.8-0.9 Egyptian cotton 1.16-1.74. Unbuffered Methylene Blue solutions give lower values viz., 0.45 and 0.65 respectively. Methylene Blue absorption of cotton depends on the ash alkalinity of the cotton and the value decreases as the ash alkalinity decreases. 

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Limestone used as a filler should be free of the organic compounds—French Standard limits their content to 0.5 %. The clay admixture should be as low as possible, it is determined from the methylene blue absorption test, which should not exceed 1.5 g per 100 g of filler with the fineness below 80 pm [16]. Simultaneously, cement with limestone addition should give the paste of standard consistency, at water content lower than 30% [171]. 

The damages that occur during various pre-treatment processes of cellulosic fibres can be detected by various chemical tests like fluidity, copper number. Methylene Blue absorption and silver nitrate staining etc. 

A test that measures the quantity of carboxyl groups uses methylene blue absorption. A sample of the paper is immersed in a solution of methylene blue and the absorbance of the dye solution at 620 nm is measured before immersion of the paper and at the end of the experiment. The amount of sample needed to produce 50% exhaustion of the dye solution is used to calculate the carboxyl content. 

SnC>2 nanoparticles have been successfully synthesized by chemical co-precipitation method using ethanol, acetone, tetrahydrofuran (THF) and ether as solvents. X-ray Diffraction (XRD), Field Emission Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) have been used to study the crystallographic and morphological properties of synthesized SnC>2 nanoparticles, while their optical properties have been studied by UV-Visible absorption spectroscopy. UV-Vis absorption spectra shows a weak quantum confinement in all the synthesized SnCL samples. The photo-catalytic activity of as-synthesized SnC>2 nanoparticles under UV irradiation has been evaluated using Methylene Blue (MB) dye as a test contaminant in water. The results showed that solvents played a key role to control the morphology and photo-catalytic activity of SnCE nanoparticles. 

Cotton is also tested for ligneous matter by absorption of dyes (fuchsine, methylene blue, malachite gpreen) and for the viscosity of its solution in cuprammonium liquor. Gabillion gives the following figures for various cottons —... 

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