Revista de química analítica ambiental

Comparison of Various Additives in Cotton Bleaching Efficiency

Abstract

Aisha Nazir, Fariha Arooj and Saifur Rehman Kashif

Bleaching efficiency is evaluated by the degree of whiteness, absorbency, copper number, tendering factor, strength or strength loss, dye uptake, alkali solubility, degree of polymerization and chemical transformation. Recent lab-scale studies have proven ozone to bleach with efficiency comparable to the conventional bleaching agents and hydrogen peroxide at faster rates without requiring heating or any other supportive treatment with less energy and water. Ozone alone, however, showed poor efficiency in pilot-scale determinations, suggesting the use of certain additives to support it in performing its bleaching action. This research was conducted to compare the influence of methanol, isopropanol, oxalic acid and sodium borohydride on improvement in the bleaching performance of ozone in terms of whiteness, absorbency and burst strength. The additives brought an overall improvement in whiteness, absorbency and burst strength of cotton but had significant difference in their performance, as assessed from the pvalues yielded by one-way ANOVA applied on SPSS 20. Methanol outclassed other three in its performance bringing the highest increase in whiteness and burst strength and the highest reduction in fabric absorbency.