Basic dye removal

Wang, S Li, H Xu, L. Application of zeolite MCM-22 for basic dye removal from wastewater. Journal of Colloid and Interface Science, 2006 295,71-78. 

R. Ansari, M. S. Tehrani, M. B. Keivani, Application of polythiophene-sawdust nano-biocomposite for basic dye removal using a continuous system. / Wood Chem Technol 2013, 33 (1), 19-32. 

Food samples are dissolved in water and acidified with acetic acid (135,157). According to Gilhooley et al. (157), excess methanol has to be removed from solutions before passing through polyamide because it impairs the adsorption of the dyes by the polyamide. The solution is stirred with polyamide powder, and the slurry is transferred to a microcolumn or it is passed through the column of polyamide. The latter is recommended since dyes are adsorbed as a narrow band at the top of the column. The column is washed with hot water to remove sugars, acids, and flavoring materials and with acetone to remove basic dyes, water-soluble carotenoids, and some antho-cyanins. The adsorbed acid dyes are eluted with methanol sodium hydroxide (164,172,175), with methanol ammonia (176), or with acetone ammonia (157). Acetone ammonia is preferred because it can be removed in a water bath and, on addition of acid, no salts are formed that interfere with the adsorption of the dyes by the polyamide (157). The eluate is evaporated to dryness and redissolved in the HPLC mobile phase (156). 

Nandi and Walker [499J compared the uptakes of two acidic and one basic dye by coals, chars, and activated carbons and noted that the area covered by a dye molecule would depend on the nature of the solid surface. They concluded that the removal of acidic groups by heat treatment had an effect on dye uptake for one activated carbon but had no effect for another. The authors did not report the pH of the adsorption measurements, nor did they characterize the surface chemistry of the adsorbents. McKay [500] did report the pH and even studied the effect of pH (in the range 5.2-8.5) on the rate of adsorption of Telon blue (an acidic dye), but the effect was neither clarified nor found to be significant. In contrast, Perineau et al. [501] noted major effects of pH on the adsorption of both an acidic and a basic dye and concluded that pH values of about 2 are the best for the adsorption of acid dyes whereas less acidic values (pH > 5) are to be preferred for the removal of basic dyes. ... 

J.S.D.C., 1934, 50, 342) showed that it was very difficult to remove the primary amino groups from wool completely, and previous workers had also failed to do so. When they applied drastic conditions to bring about deamination they were able to demonstrate a decreased affinity for acid dves and, conversely, an increased affinity for basic dyes on account of the... 

The basic dyes differ from all others because they are extracted quite easily by boiling with acetic acid or with alcohol. If, however, these reagents do not remove a substantial portion of the dye from the fibre, the next test is to boil the coloured material in dilute ammonia (1 ml of 0-88 ammonia per 100 ml of water) for 1 to 2 minutes in the presence of white cotton (Clayton, foe. cit.). If the solution is distinctly coloured and the cotton remains unstained, the presence of an acid dye is indicated. This can be confirmed by boiling with 40 per cent of Glauber s salt when a considerable proportion of molecularly-dispersed acid dyeS are stripped, but little effect is apparent with the fast acid dyes. If the cotton is stained the presence of... 

Janos P, Smidova V. Effects of surfactants on the adsorptive removal of basic dyes from water using an organomineral sorbent - iron humate. J Colloid Interface Sci 2005 291 19-27. 

R. Ansari, Z. Mosayebzadeh, Removal of basic dye methylene blue from aqueous solutions using sawdust and sawdust coated with polypyrrole. J Iran Chem... 

The relative costs of the sorbents for the two basic dye systems are shown in Table 15.11 together with the sorption costs of removing 1 kg of dye. Carbon was taken as the standard, having a comparative unit cost per kilogram, and the relative costs of the other adsorbents are shown in the third column of Table 15.11. The mass (kg) of adsorbent required to remove 1 kg of dye is obtained from the dye isotherms and consequently, using columns 3 and 5, a comparative cost of different adsorbents to remove 1 kg of dye may be obtained this is shown in column 4. The benefits of using peat, based on this simple analysis, are apparent. 

McKay, G. and F. Alexander. 1977. Kinetics of the Removal of Basic Dye from Effluent Using Silica. II Fluidised Bed Studies, Chemical Engineering, vol. 319, pp. 244-247. 

A technique to produce highly concentrated solutions of recovered basic dyes has been developed and a patent issued (Moser et al 1984). The technology described is based on reverse osmosis and ultrafiltration. More recently, Gupta et al. (2004) developed a process for removal and re-use of the basic dye malachite green, which is a snbstitnted triphenyl methane dye. As adsorbent bottom ash was used, dye adsorption was almost 100%. Bottom ash is itself a waste product from thermal power generation plants. Malachite green was desorbed with acetone almost quantitatively to 96% and the colnmn, loaded with bottom ash, conldbe reused without loss of efficiency. 

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