Reuse of Peracetic Acid Bleach Bath for Bleaching of Different Ligno Cellulosic Fibres

Our country several resources of plant fibres like jute, banana, ramie, flax, etc, which is grown indifferent parts and agro climatic zone and are having immense impact on the socioeconomic values.These fibres consist of cellulose, hemicellulose and lignin as major constituents and due to theirbiodegradable and renewable in nature are becoming popular in textile and non-textile applications asa replacement of synthetic fibres and plastic items. Several diversified and value-added items areproduced from these fibres like upholsteries, lifestyle products, varieties of fashion bags, handcrafts,etc along with mainstream products. So, chemical processing of these fibres has become essential andstandardization of different unit operations like pre-treatments, bleaching, dyeing, printing, finishing,etc are needed to make them look beautiful and feel better. A few processes have been developed andrequire further modification for their sustainability. Bleaching is the heart of the chemical processingfor all the subsequent processes are solely dependent on it for optimum results. Traditional bleachingusing hydrogen peroxide is very popular in industry but along-with the achievement of high whitenessand brightness indices it results in substantial loss in tensile properties as the process is carried out athigh alkaline condition as well as temperature, which damages these lignocellulosic fibres. So, aninnovative peracetic acid bleaching process has been developed that is carried out at lowertemperature in mild alkaline condition. Jute, banana, ramie and flax fibres contain cellulose,hemicellulos, and lignin in different proportions in different fibres. Hence optimized condition ofchemical processing varies for individual fibres. The peracetic acid bleaching process has beenoptimized for individual fibres using Taguchi Experimental Design (TED) and the optimized processesproduces satisfactory whiteness/ brightness with high retention of tensile strength. To make the processsustainable, the left out bleach bath formulation has been re-claimed and it has been found that the leftout liquor need to be used for further two batches of grey fibres to produce semi-bleached and quarter-bleached fibres which can be utilized for dyeing in variety of shades. The reuse of bleach bath can bedone by different methodologies like compensation of bath or without. It is found that 1st reuse can bedone without compensation but 2nd reuse produces better effect if compensation is done for liquor andpH correction.