The Effect of Environmentally Friendly Complexing Agents Used as Stabilizers for Hydrogen Peroxide in the Bleaching Bath of Cotton Fabric

摘要

This study gives a relative analysis on the performance of conventional and new generation biodegradable complexing agents used asstabilizers for hydrogen peroxide bleaching of cotton fabric. The role of stabilizers is to reduce the speed of hydrogen peroxide decomposition by forming complex with hydrogen peroxide, i.e. a mediator composite and with metal ions in the solution. NTA (nitrilotriacetic acid) and EDTA (ethylenediaminetetraacetic acid) were the first conventional complexing agents used as stabilizers for hydrogen peroxide bleaching. But the problem of low biodegradability of conventional stabilizers led to search for more improved biodegradable stabilizers. One conventional and three new biodegradable stabilizers for hydrogen peroxide were investigated under equal conditions. These areethylenediaminetetra-acetic acid, Iminodisuccinic acid (N-1,2-dicarboxyethyl)-D,L-aspartate acid, N,N-bis(carboxymethyl) glutamic acid and Ethylenediamine- N,N’-disuccinic acid. The criteria selected for assessing stabilizer performance was to carry out hydrogen peroxide bleaching in the presence of substrate and metal ions. In addition residual hydrogen peroxide over a period of time in the presence of different stabilizers was measured. To understand more about the effect of stabilizers, other parameters such as whiteness index, tensile strength, absorbency and fluidity were studied. The CIE whiteness index assessment of fabrics was measured by a spectrophotometer using suitable computer software. A universal strength Tester (Titan) was used to measure tensile strength. An Ostwald - FenskeCuenviscosimeter was used to determine chemical degradation of cotton fabric by measurement of its fluidity and an embroidery hoop was used to determine absorbency. This study has revealed valuable information for industrial use ofnew generation biodegradable complexing agents asstabilizers for hydrogen peroxide bleaching of cottonfabric. As a consequence of this analysis, extremely dynamic biodegradable stabilizers for hydrogen peroxide bleaching as a substitute to conventional stabilizers were found.