Abstract

A Na2S/LiBr/SDS dissolution system was used to dissolve waste wool and extract wool keratin by microwave-assisted technology. The optimization of wool keratin preparation was critically investigated via orthogonal experimental design. Experimental results indicated that microwave time had a far greater effect than other parameters on wool dissolving process. Under the optimal conditions (microwave time: 10 minutes, 0.5mol/L Na2S, pH:10, reaction temperature: 80°C, 0.2mol/L LiBr), the wool dissolution rate (WDR) and keratin extraction rate (KER) were 98.8% and 69.6%, respectively. Wool keratin has a rich amide structure as shown by FTIR analysis and can be used as free formaldehyde scavenger for leather products. Moreover, the application properties of keratin were evaluated by formaldehyde capture experiments. It turned out that the formaldehyde removal rate (FRR) achieved the highest peak at 52.5% by addition of 4% keratin formaldehyde scavenger (KFS) and a capture time of 1.5 hours. Meanwhile, the leather thickening rate (LTR) increased by 6.36%, which testified that KFS possessed a certain filling effect for leather samples at the same time as removing formaldehyde. Wool keratin might have a great potential for application in leather products as environment-friendly formaldehyde scavenger.