Study On Ozone Treatment Of Color Fading On Reactive Dyed Cotton Fabric

Denim was invented for over 150 years,it is always classic and shows a rosy prospect.The fading treatment – a garment finishing process is one of the reasons which makes denim popular for last decades.Conventional fading treatments mainly were designed on the basis of indigo which possess a feature of low fastness,these treatments such as hydrogen peroxide and chlorine bleaching also have a range of negative influences on environment,like consuming time,water and power,by-producing a huge amount of wastewater at the same time.These would prevent denim from keeping popularity in the future.In this study,ozone,a oxidant gas which has been successfully applied in the industry of dyeing wastewater decolorization,was employed to seek the potential for alternating conventional treatments and developing an environment-friendly method in the area of fading reactive dyed cotton.The cotton,tencel and PET yarns treated by ozone at different pH and with different moistures over different durations were characterized by SEM,FTIR and tensile tests respectively.The results show that the cellulose in cotton and tencel was oxidized,and the –OH group in it were oxidized to be –CHO,which resulted in their tensile property loss.This negative impact is more evident in the cases of strong acid and alkali.PET has compact structure and high crystalline.Its microstructure,chemical structure and tensile property were steady in every single experiment whatever the treating parameters varied in this work.The kinetic studies of ozone decolorizing Reactive Blue FJ-RN(RB),Reactive Red FJ-2BL(RR)and Reactive Yellow(RY)and their corresponding dyed cotton fabrics were introduced in this paper,and the result illustrated that the reaction between ozone and aqueous solution are pseudo-first-order reaction,while the reaction between ozone and dyed fabrics are pseudo-second-order(for RB and RY dyed cotton)and pseudo-third-order(for RR dyed cotton)respectively,which means that the latter are much more complicate than the former reactions.The effects of pH and temperature are unparalleled on different dyed fabrics.The kinetic constant i.e.K in ozone fading RB dyed cotton dropped persistently when pH increase from 1 to 13.However,this phenomenon were opposed in RR and RY corresponding experiments,and their K generally increased with pH by 10 but decreased dramatically at pH13 simultaneously.Meanwhile,higher temperature in the range of 0-80℃ is able to promote the K in RB and RY experiments,but a peak at 40℃ in the RR experiments shows a difference.These differences demonstrate the significance of dye’s characteristics and properties in their dyed cotton’s ozone fading treatments.Comparing with pH and temperature,the effect of moisture on ozone fading reactive dyed cotton were familiar in each single experiment of different color fabrics that the moisture of 75% strongly promoted K in each ozone treating experiment and is better than the fading treatment in 150% and 0 content.The Ozone/UV collaborative treatment on colour fading reactive dyed cotton and the comparison with conventional fading processes such as Hydrogen Peroxide(H2O2)and Chlorine(NaClO)in terms of the effect on colour fading,mechanical properties(the tensile strength and elongation,tearing strength and abrasion resistance)and surface microstructure in SEM were investigated.UV was clearly illustrated that promotes the ozone fading effect and such collaboration efficiency is far better than conventional treatments with less negative impact in all of the mechanical property related items above.Overall,it possess an excellent potential to alternate the conventional processes as it not only performs better in the evaluations but also is capable to save a huge amount of water and power.