| Feather is a kind of wastes, and also a kind of renewable resource. Abstracting soluble keratin from feather by reduction method is a hotpot, however, few investigations have focused on the residues generated in the reduction reaction. In this investigation, keratin sponge film was made from feather reduction residue and characterized; application of the film in aerosol filtration and Cr(VI) adsorption was studied.In keratin sponge film preparation, we chose the residue rather than the soluble keratin to prepare the film which made the residue get more effective reuse and also increased the utilization rate of feather wastes. The method was easy, the film had good flexibility and surface morphology. In the reduction reaction, we studied the influence of SDS on productivity, the result showed that under the best mass ratio while SDS to feather was0.5, the productivity of soluble keratin and residues were5.8%and65.2%respectively. In film formation process, we investigated the influence of glycerol content on film’s mechanical characteristics, microstructure and thermostability, the result showed that while glycerol content was5%the film had the best integrity, flexibility and thermostability; melting point of the film was about170℃and apparent density of the film was0.52g/m3. Through comparison of feather, residues and the keratin sponge film by FTIR, we found that there were more functional groups contained in the products after reduction reaction and film formation, expecially functional groups of amide I band and hydroxyl groups. Increase of amino-group indicated that urea played important role on the product formation. Increase of hydroxyl groups and water absorption characters showed that the film was hydrophilic while the feather was hydrophobic. Specific absorption of volume of the film was420%. From element test, we found that the film had higher content of C and N than feather, which furthur indicated that urea played an important role on product formation in the reaction.To evaluate the film’s application in air pollution treatment, we tested the film’s aerosol filtration performance. Taking both the result of aerosol filtration and air permeability into consideration,5%was chosed as the best glycerol content. Under5%glycerol content, the film’s removal rate of PM10, PM2.5and PM1.0was98.03%,39.28%and32.97%respectively. Its air permeability was368mm/s, mean pore size was180nm, porosity was80.5%. As a protein film which had good flexibility and affinitive, the film had large potential to be used in mask manufacture.To evaluate the film’s application in water treatment, adsorption of Cr(VI) on the film was studied. The result showed that the film had better adsorption effect on removal of higher Cr(VI) concentration. At60℃, Cr(VI) initial concentration100mg/L, pH6and90min, the biggest adsorption capacity was148.8mg/g which was better than many other adsorbents made from agriculture wastes, moreover, using film as adsorbent rather than power made the separation process more easily. This adsorption process was a endothermic and spontaneous process which was easy to go, the adsorption process fitted both Langmuir and Freundlich models, and both physical and chemical function played important role on this adsorption. After adsorption, there were many particles appeared on the film’s surface, and the film contained less functional groups than before, α-helix keratin was reduced while P-fold keratin didn’t changed much after adsorption, so we speculated that a-helix keratin was easier to be oxidized than β-fold keratin.The outcome of this investigation will provide theory support and practical guide for feather wastes reuse. |
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