Eco-Friendly Bleaching of Cotton Fabrics Without Heating Using Direct Process Water in the Presence of Sodium Chlorite and Phosphonate

Abstract

A large amount of chemicals, water and energy are used during the bleaching of raw cotton fabrics. For this reason, it is extremely important for economic and ecological aspect to develop eco-friendlier bleaching technology that eliminates the need for heat energy, process water, and wetting agent in the bleaching of these fabrics. Here, we report on green approach for industrial-scale bleaching with sodium chlorite (NaClO2) in presence of phosphonates (HEDP), which is used as both wetting agent and pH regulator and contributes to the high whiteness of fabrics. In bleaching, the process water was used in ambiant temperature as flote without any heating process, thus reducing the energy requirement significantly. In the measurements, it was observed that the whiteness value (W.I. = 72.6) obtained after 8.0 h bleaching at 20 degrees C which was very close to the whiteness value (W.I. = 74.2) of reference W-1 fabric. Also, it has been confirmed that cotton fabrics bleached with NaClO2 have higher strength values, less damage, and residue on the fabric compared to reference fabrics, as well. This study showed that cotton fabrics can generate a small amount of wastewater and can be successfully bleached in the presence of NaClO2 without the need for any heating energy.