Fabrication Of In-situ Grown ZIF-8@Lyocell/feather Based Nonwoven And Its CO₂ Adsorption Properties

The excessive emission of carbon dioxide has led to the increasingly serious greenhouse effect,causing global warming,sea level rise,land desertification and other environmental problems,and human survival is greatly threatened.Solid adsorption technology is one of the most effective means of capture and treatment at present.Metal organic frameworks（MOFs）have large specific surface area and pore volume,multiple topological structures,stable physical and chemical properties,and are good adsorption materials.However,nano particle materials still face the following problems:easy to cluster and fly;It is difficult to be self-supporting molding,resulting in low single use rate and difficult recovery after use.In this regard,the solution blending electrospinning technology can realize the composite molding of nano particles and fibers,and endow the fiber membrane with a self-supporting structure.However,the electrospun membrane used for CO₂ capture still has some shortcomings in practical applications,such as raw materials are difficult to degrade and easy to cause secondary pollution;The preparation process is time-consuming and energy consuming,and the mechanical strength of the obtained material is low;The single function makes it difficult to give consideration to both physical adsorption and chemical reaction CO₂.Abandoned feathers are long underestimated biomass resources,in which rich amino groups can chemically adsorb CO₂.Zeolite imidazole ester framework（ZIF-8）is a nano porous granular material composed of transition metal atoms Zn and imidazole.Its pore diameter is 3.4?slightly larger than CO₂’s aerodynamic diameter of 3.3?.It is an ideal CO₂adsorption solid material.If ZIF-8 particles that can physically absorb CO₂ are combined with feather keratin that can chemically react with CO₂,the material can be endowed with dual CO₂ capture performance.Therefore,this paper selects Lyocell nonwovens as the support material,and after acupuncture and reinforcement with reduced feather fibers,prepare micro nano size biomass based composite nonwovens,and then use the in-situ growth method to plastic the powder ZIF-8 into a macro three-dimensional network structure to explore the composite nonwovens loaded with ZIF-8（ZIF-8@CN）Application in the field of carbon capture.The specific research contents are as follows:（1）Preparation of Lyocell/feather composite nonwovens.Lyocell fiber and waste feather were selected as raw materials,which were respectively fibriled and reduced,and then needle punched to prepare micro/nano fiber composite nonwoven substrate with three-dimensional space network.Explore the best processing conditions of raw materials:Na OH concentration and ultrasonic vibration time are important parameters for the fibrillation of Lyocell non-woven fabrics.When the Na OH mass fraction is 3%and the ultrasonic time is 20 min,the fiber surface is full of grooves,and smaller secondary fibrils appear on the stripped thicker fibrils,forming micro nano structures.At this time,the fibrillation index is FI=7.31;The fibrotic functionalization of discarded feathers is an important step in the molding of textile materials.After 2 h reduction treatment,the disulfide bond between protein macromolecules is opened to maximize the exposure of surficial active groups,and at the same time,the flexibility of feather trunk is increased,which is conducive to the subsequent molding and preparation of highly stable three-dimensional structure composite nonwovens.（2）To explore the best conditions for the in-situ growth of ZIF-8 particles on the surface of Tencel/Feather nonwovens.When the molar ratio of Zn²⁺:2-mim:Me OH is 1:8:1000,the regular dodecahedral ZIF-8 particles with complete lattice and 320 nm particle size are grown on the surface of the nonwoven material at room temperature.There are hydrogen bonds and electrostatic interactions between ZIF-8 and composite nonwovens,resulting in ZIF-8 particles adhering closely to the fiber surface and having good interface bonding fastness with the materials.（3）To explore the best standing growth time of ZIF-8.Different growth time（3 h/6 h/9h/12 h）ZIF-8@CN The surface morphology and chemical structure of composite nonwoven materials are affected.When the standing growth time is 9 h,the surface of the nonwoven material is tightly wrapped by the particle layer of ZIF-8,and the unsaturated metal sites of ZIF-8 are completely exposed on the surface of the material,with a loading rate of 12.41%.ZIF-8＿9h@CN The specific surface area reached 108.90 m² g^-1,about 12 times of that before loading,and the micropore volume was 0.035 cm³ g^-1,about 4 times of that before loading.Therefore,ZIF-8＿9h@CN is a promising CO₂ capture material.（4）Inquiry ZIF-8@CN Adsorption performance in high concentration CO₂ and low concentration CO₂ environment.Measured by BET ZIF-8＿9h@CN The adsorption capacity of the material in the high concentration environment at 298 K temperature is 4.46 cm³ g^-1;In a sealed chamber（5 L）at 298 K,1.0 bar and with an initial CO₂ concentration of 2000 ppm,after120 min of adsorption reaction,the CO₂ concentration in the sealed container is reduced from the initial value of 2000 ppm to 1854 ppm,and its adsorption capacity is 0.604 mmol g^-1.After five cycles of CO₂ adsorption desorption,the CO₂ adsorption capacity is 161.43 ppm g^-1,84.7%of the initial adsorption capacity(190 ppm g^-1).This shows that ZIF-8@CN is a CO₂ adsorption material with excellent potential in industrial promotion.