Colour removal

P-Hydroxy-a-naphthaldehyde, Equip a 1 litre three-necked flask with a separatory funnel, a mercury-sealed mechanical stirrer, and a long (double surface) reflux condenser. Place 50 g. of p-naphthol and 150 ml. of rectified spirit in the flask, start the stirrer, and rapidly add a solution of 100 g. of sodium hydroxide in 210 ml. of water. Heat the resulting solution to 70-80° on a water bath, and place 62 g. (42 ml.) of pure chloroform in the separatory funnel. Introduce the chloroform dropwise until reaction commences (indicated by the formation of a deep blue colour), remove the water bath, and continue the addition of the chloroform at such a rate that the mixture refluxes gently (about 1 5 hours). The sodium salt of the phenolic aldehyde separates near the end of the addition. Continue the stirring for a further 1 hour. Distil off the excess of chloroform and alcohol on a water bath use the apparatus shown in Fig. II, 41, 1, but retain the stirrer in the central aperture. Treat the residue, with stirring, dropwise with concentrated hydrochloric acid until... 

Lourenco ND, Novais JM, Pinheiro HM (2000) Reactive textile dye colour removal in a sequencing batch reactor. Wat Sci Technol 42 321-328... 

Talarposhti AM, Donnelly T, Anderson GK (2001) Colour removal from a simulated dye wastewater using a two phase anaerobic packed bed reactor. Water Res 35 425—432... 

Y. Coque, E. Touraud, O. Thomas, On line spectrophotometric method for the monitoring of colour removal processes, Dyes and Pigments, 54, 17-23 (2002). 

Reid, R. On-site colour removal at Courtaulds Textiles. J. Soc. Dyers Colour. 1996,112, 140-141. Horak, O. Katalyische NaBoxidation von biologisch schwer abbaubaren Abwasserinhaltsstoffen unter milden Reaktionsbedingungen. Chem. Ing. Tech. 1990, 62, 555-557. 

Willmott, N. Guthrie, J. Nelson, G. The biotechnology approach to colour removal from textile effluent. J. Soc. Dyers Colour. 1998, 114, 38-41. 

Fung PC, Huang Q, Tsui SM, Poon CS. Treatability study of organic and colour removal in desizing/dyeing wastewater by UV/US system combined with hydrogen peroxide. Water Sci Technol 1999 40 153-160. 

The application of photocatalysis to textile chemicals such as the azo dyes acid red 14 and acid orange 8 and acid orange 7 has been reported [ 138-140]. Complete colour removal was achieved for each of these materials within 3 h while use of additives such as H2C>2 in millimolar quantities enhanced the destruction rates. The addition of ethanol, a hydroxyl radical quencher, was... 

C. Namasivayam and N. Kanchana, Waste banana pith as an adsorbent for colour removal from wastewaters, Chemosphere, 25,1691-1705,1992. 

The efficiency of coloured matter coagulation for solution 1 and solution II depended both on the dose and on the type of the dolomite coagulant applied. Figure 2 shows colour removal as a function of coagulant B dose. Thus, the dose... 

Colour removal from solution II followed a different behavioral pattern. No significant difference in the removal efficiency was observed between the two coagulants up to the dose of 300 g m . When doses ranged between 300 and 500 g m, ... 

The relationship between pH and colour removal is given in Figure 3. As shown by these plots, the desired removal efficiency was achieved for solution I and solution 11 at pH about 11.0 with coagulant A and at pH about 10.0 with coagulant B. A further increase of pH had no significant effect on the degree of colour removal. 

Turbidity removal by dolomite coagulation proceeded in a manner different from that of colour removal. Figure 4 relates the removal efficiency to the dosage of coagulant B. Thus, during coagulation of solution 1 which had an initial turbidity T = 0, the samples became turbid. This should be attributed to the precipitation of fine-crystalline calcium carbonate particles. When the dosage... 

Colour removal from model solutions of a moderate coloured matter... 

B. Inane, F. Ciner, and I. Ozturk, Colour Removal from Fermentation Industry Effluents, Water Sci. Tech. 40(1), 331-338 (1999). 

Hung Y.S. (1995) Huang C.R. et al. (1994) tried to use ozone to decolour the dy-eing effluent containing Direct Black and Blue dyes. The author found that the efficienc y of colour removal was highest at neutral pH 6.45 but not at alkaline pH. Nevertheless, Carriere J. et al. (1991) concluded that the decolouration of some commercial dyes occurred faster at higher temperature and higher pH. 

Ozonation system consists of the following sections a. feed-gas treatment b. ozone generation c. ozone-water contact mechanism and d. destruction unit (Lin S.H., 1993). The use of ozonation in preliminary treatment is not economic effective even it can decrease the soluble organic. Therefore, it is better to implement Ozonation in tertiary treatment for effectively colour removal of the residual dyes. 

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