Study On The Adsorption Properties Of Chitosan-based Composites For Formaldehyde

In recent years,the emission of formaldehyde has seriously polluted the environment and harmed people's physical and mental health.Therefore,how to effectively remove formaldehyde has attracted more and more attention.At present,the removal methods of formaldehyde mainly include biodegradation,adsorption and oxidative degradation.Among them,the adsorption method has become a major method due to its simple operation and low cost.However,most of the current adsorption methods are physical adsorption,while chemical adsorption It is rarely involved.Therefore,in this paper,the modified natural chitosan rich in amino groups in the structure is selected as the substrate,and manganese dioxide(catalytic oxidation)and graphene oxide(chemical adsorption)are respectively loaded to prepare two types of binary composite materials,and the structure is composed.And performance characterization.The research work is as follows:(1)The chitosan-based composite material CSMX with different loadings of manganese dioxide was prepared by the in-situ growth method,and its structure and composition were characterized by XRD,FT-IR,XPS,SEM and TG-DSC.The results of the study showed that manganese dioxide was accumulated on the surface of chitosan in a granular form to form a porous structured composite material,of which CSM1.6 loaded the most manganese dioxide;the thermal stability of chitosan in the composite material increased.(2)According to the analysis results of single factor experimental data,Langmuir model and thermodynamic model:the maximum adsorption capacity of CSM1.6 is 5.62 mg/g,and the entire adsorption process conforms to the second-order kinetic model and is an exothermic reaction;CSM1.6 The adsorption of formaldehyde is achieved through physical adsorption and chemical adsorption of the amino groups on the chitosan surface and the catalytic oxidation of MnO₂.(3)The composite aerogel CSGX with different graphene oxide content was prepared by freeze-drying technology,and its structure and composition were characterized by XRD,FT-IR,Raman,SEM,XPS and TG.Through research,it is found that chitosan and graphene oxide form a porous lamellar network structure through hydrogen bonding and electrostatic interaction;CSG10 shows good structural stability in water,and its thermal stability is better than that of CS and GO.(4)Through the analysis of single factor experimental data,Langmuir model and thermodynamic model,it can be seen that as the content of graphene oxide increases,the removal rate of formaldehyde by the composite material is getting higher and higher,and the adsorption process conforms to the second-level kinetic model.Exothermic reaction;the adsorption of formaldehyde by CSG10 is achieved through the combined effect of physical adsorption of the pore structure and chemical adsorption of amino groups and oxygen-containing oxygen groups on the surface of the aerogel.