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|Title:||Decolourisation of metal complex azo dyes and treatment of a dyehouse waste by modified photo-Fenton (UV-vis/ferrioxalate/H<sub>2</sub>O<sub>2</sub>) process|
|Series/Report no.:||Int. Cl.<sup>7</sup> C09B 57/10|
|Abstract:||In a laboratory study, decolourisation of three metal complex azo dyes (Acidol Yellow, Acidol Grey and Acidol Scarlet) in mixture by the modified photo-Fenton (UV-vis/ferrioxalate/H<sub>2</sub>O<sub>2</sub>) process, and treatment of a dyehouse waste containing the three dyes were examined. From decolourisation of the dye mixture, process conditions for decolourisation were selected – <i style="">p</i>H 4, Fe(III) dose 12.5 mg/L, oxalic acid dose 50 mg/L, hydrogen peroxide dose 60 mg/L and irradiation time 90 min. Ninety-two percent decolourisation of the dye mixture (colour 120 SU) occurred in 90 min under irradiation with sunlight intensity in the range 0.5-0.8 kW/m<sup>2</sup>. The process was found effective in decolourisation of highly coloured solutions. Modified photo-Fenton decolourisation of the synthetic dyehouse waste (<i style="">p</i>H 7.5, colour 120 SU, COD 260 mg O<sub>2</sub>/L, BOD<sub>5</sub> 125 mg/L, turbidity 1.5 NTU, conductivity 1265 mmho/cm and total solids 875 mg/L) under selected process conditions and irradiation with sunlight or incandescent lamp, was also studied. Ninety-two percent decolourisation (residual colour ca 10 SU) was achieved under 90 min irradiation with sunlight (0.5-0.8 kW/m<sup>2</sup>) or incandescent lamp (6.5 kW/m<sup>2</sup>). A depth of 30 cm was found to be the maximum depth for decolourisation. The study has demonstrated that modified photo-Fenton is an effective process for decolourisation of dyehouse waste containing metal complex azo dyes. A scheme for oxidative treatment of the dyehouse waste was formulated and the treatment efficiency was evaluated – 90-92% or 90-92%, 69-70% or 63-73%, and 52-65% or 50-60% removal of colour, COD and BOD<sub>5</sub> were achieved under irradiation with sunlight or incandescent lamp.|
|ISSN:||0975-1017 (Online); 0971-4588 (Print)|
|Appears in Collections:||IJEMS Vol.11(6) [December 2004]|
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