Preparation Of Metal Complexes And Its Application In Hydrogen Peroxide Bleaching Of Cotton Fabrics

Traditional hydrogen peroxide bleaching has the problems of high energy consumption and serious fiber damage,Because conventional hydrogen peroxide bleaching process is in the violent conditions（high temperature,alkali）.To solve this problem,in this paper,a metal complex was prepared from glutathione and copper sulphate and applied to the hydrogen peroxide bleaching of cotton fabric.the study built a new hydrogen peroxide/metal peptide complexes bleaching system.The main factors affecting the complexesand the bleaching effect of the complexes as a low temperature bleaching additives for cotton fabric were discussed.The optimal chelation conditions were determined including pH,a molar ratio between cupper ion and peptide,temperature and time.its for:pH=8,molar ratio of copper ion to peptide=1:2,reaction temperature is at room temperature（25℃）,The reaction time was 24h.The reaction products were analyzed and characterized by UV-Vis,IR and TG and the stability constants of the complexes were determined.The results showed that the metal complexes formed.The impact of the amount of metal complexes,hydrogen peroxide,and the effect of the type of the bleaching temperature,alkali agent,and bleaching time on the whiteness,capillary effect and strength retention rate of cotton fabrics were studied by Single factor and response surface methodology.The best technological conditions for hydrogen peroxide bleaching were:metal complex 2g/L,30%H₂O₂10ml/L,penetrant JFC 1g/L,scouring agent 0.07g/L,70℃for 20min,then treated with 3g/L sodium silicate for 40 min at 70℃.The application of metal complexes in the process of cotton-wool knitted fabric warm-up and bleaching-bath process was discussed.The optimum process was optimized:metal complex dosage was 6g/L,30%H₂O₂ 30ml/L,sodium silicate 8g/L,scouring agent0.4g/L,penetrant JFC 3g/L,two baptist two rolling,rolling rate of 100%,70℃piled up60min.The bleaching effect of the cotton fabrics with metal complex was evaluated.The results show that the metal complex can catalyze the decomposition of hydrogen peroxide and reduce the hydrogen peroxide bleaching temperature.The whiteness,capillary effect of the fabric bleaching with the Metal complex/hydrogen peroxide system can achieve the effect of the traditional high temperature alkali bleaching process.but the fabric strength damage was significantly reduced.In order to improve the bleaching effect of the metal complex/hydrogen peroxide system on the cotton fabric,the plasma pretreatment and urea were added into the system.The results showed that if the fabric was pretreated with appropriate conditions,or added appropriate urea in the bleaching bath,will further enhance the metal complex/hydrogen peroxide system on the cotton fabric bleaching effect.The mechanism of metal complex/hydrogen peroxide bleaching at low temperature and the effects of metal complexes on the decomposition rate of hydrogen peroxide were studied.The results showed that the decomposition rate constant of hydrogen peroxide in the metal complex/hydrogen peroxide system increased significantly,and the half-life was obviously reduced.At the same time,the adsorption of metal complexes on cotton fabric was also studied.The experimental data were simulated by quasi-first-order kinetics model and second-order kinetics model.The results showed that the metal the adsorption process of the complex on cotton fabric accords with the quasi-second order kinetic model.The decolorization kinetics of metal complexes/hydrogen peroxide solution was studied.The reaction rate constant and reaction activation energy were calculated.The results showed that the decolorization process of metal complex/hydrogen peroxide system was in good agreement with the standard.The activation energy decreased from 55.35 kJ/mol to 25.36 kJ/mol,and the decolorization rate increased remarkably.