Electrochemical bleaching of cotton

Das, Dipankar ; Patra, A K; Jakhar, Rahul ; Sundar, Shyam

Abstract

An attempt has been made to compare the effect of electrochemical bleaching with conventional bleaching of cotton. Electric current is used in the preparation of a bleaching agent to replace bleaching powder. The NaOCl generated from electrolytic cell (2.5-3.5V potential difference) is sufficient to produce powerful bleaching agent with available chlorine varying from 1.2 g/L to 1.3g/L. Time required for bleaching reduces to 10-20 min, as compared to 90 min in conventional bleaching. Whiteness index, brightness index and yellowness index have been measured by a spectrophotometer. There is a remarkable increase in whiteness index and brightness index and decrease in yellowness index in the electrochemically bleached samples as compared to that in conventionally bleached cotton. Dye uptake values show an increasing trend with electrochemical bleaching. The present study aims for achieving the desired efficiency to remove conventional drawbacks of sodium hypochlorite bleaching.


Keyword(s)

Brightness index; Electrochemical bleaching; Sodium hypochlorite; Whiteness index; Yellowness index

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