Preparation Of Wool Keratin/Sericin/Waterborne Polyurethane Blend Film And Adsorption Of Heavy Metals

In recent years,with the rapid development of the world economy and the continuous acceleration of industrialization,a large amount of soluble chemicals have been discharged into water,and these chemicals have caused serious water pollution.Among them,heavy metal pollution is the most common and most important issue in water pollution.Therefore,it is urgent to find a biodegradable,low-cost and good-performance material and method for adsorbing heavy metal ions.Both wool waste and sericin wastewater contain precious natural proteins,and wool keratin and sericin are extracted therefrom,which can protect the environment and avoid waste of resources.The water-based polyurethane is non-toxic and has good mechanical properties.In this paper,a blend film of wool keratin and sericin and water-based polyurethane can be used for the adsorption of heavy metal ions.The following conclusions are obtained:First,the wool keratin and sericin are blended with water-based polyurethane in different proportions,and the wool keratin/sericin/water-based polyurethane blend film is prepared by the freeze-drying method,and its morphological structure,mechanical properties,ultraviolet absorption Research on capabilities,swelling,etc.The results show that as the content of wool keratin increases from 0%to 80%,the content of the?-sheet structure of the blend membrane decreases,the content of the?-helical structure increases significantly,the content of the hard segment of the waterborne polyurethane is basically unchanged,and the content of the soft segment increases the trend of.It shows that the increase of wool keratin content makes the blend membrane contain more?-helix structure and soft segment structure.Correspondingly,the tensile test results also show that the content of?-helix and soft segment increase,and the toughness of the blended film increases significantly,which is conducive to the adsorption of heavy metal ions.Secondly,in this paper,the ultrasonic modification of wool keratin/sericin/aqueous polyurethane blend liquid was carried out to study the effect of ultrasonic treatment time on the properties of the blend membrane.The results show that ultrasonic treatment will affect the secondary structure transition of the protein and induce the random coil structure to?-sheet transition,which can improve the mechanical properties of the blend membrane.Therefore,the performance of the blended film can be controlled by adjusting the ultrasonic action time.In addition,ultrasonic treatment can also improve the ultraviolet absorption capacity and water resistance of the blended film.Finally,the adsorption experiments of Cu²⁺and Cr6+on wool keratin/sericin/water-based polyurethane blend membrane with ultrasonic 12min and blending ratio of 2:2:1 were conducted to study the adsorption properties of two heavy metal ions,including adsorption kinetic,Adsorption isotherm model and various factors affecting adsorption etc.The study found that it has good adsorption capacity for Cu²⁺and Cr⁶⁺,and the maximum adsorption capacity for Cu²⁺and Cr⁶⁺can reach 54.21 and 85.21mg/g.The kinetic study shows that the pseudo-second-order kinetic equation is more suitable for the static adsorption of Cu²⁺and Cr⁶⁺by blended membranes.Thermodynamic studies indicate that both Cu²⁺and Cr⁶⁺conform to the Langmuir adsorption isotherm model,and it can be considered that monolayer adsorption is dominant.