The Study Of Enzyme On The Decolocoring Process Of Human Hair

In the traditional stripping process, the use of chlorine-containing reagents for the stripping of human hair will generate a lot of absorbable organic halides（AOX） and the level of ammonia nitrogen is exceeding in the wastewater of the bleaching process. In this paper, the use of enzyme to stripping and bleaching has been studied in the decoloring process. The emissions of absorbable organic halides and ammonia nitrogen have been reduced and the processability of the decolorized human hair has been increased.The new method of protease to preprocess human hair was studied. Analyzing the performance of the scale surface, the whiteness and breaking strength of decolorized human hair in the single protease process, chloride reagent compound with protease process and different ratio between protease process by scanning electron microscope（FEI）, datacolor（X-Rite）, single fibre tensile strength tester（YG004E）. The result showed that the decolorized human hair which is treated with two-bath two-step process with papain and neutral protease have excellent whiteness and strength. Comparing the performance of the surface scales, strength and whiteness, the summarized optimum conditions are: papain dosage 4%（o.w.f）, pH=7.5, bath ratio 1:10, treatment temperature 40℃, treatment time 80 min; neutral protease dosage 3%（o.w.f）, pH=7.5, bath ratio 1:10, treatment temperature 50℃, treatment time 80 min. Compared to traditional technique, the fiber strength performance（117.5cN） can be improved by about 8% and the whiteness（22.67） improved by about 5% which stripping scales with papain- neutral protease treatment.In order to solve the problem of exceeding ammonia nitrogen content caused by the decomposition of hydrogen peroxide with ammonia catalytic in the bleaching process, we use catalase catalyzing the decomposition of hydrogen peroxide. Using catalase replace the ammonia of traditional process by screening process formula and optimizing technology conditions. New technology can not only reduce the ammonia nitrogen content in the hair and water, but also have no adverse effect on the equipment because of the nearly neutral medium. The optimum conditions of bleaching process is: catalase dosage 4%（o.w.f）, H₂O₂ dosage 3.7mL, bleaching temperature 50℃, pH= 7, bleaching time 210 min. The human hair whiteness can reach 24.60 and breaking strength can reach 114.71 cN.Adopting the new technological process of “protease stripping scale �'complex catalysis�' catalase catalytic decomposition of H₂O₂ bleaching”, the whiteness and breaking strength increased by about 14% and 6%. The mechanism of enzymatic stripping scales and bleaching put forward from this paper can provide theoretical support for processing human hair using environmental protection technology and technical basis to further enlarge application.