Study On Formaldehyde Removal Performance Of Chitosan Fiber Loaded Manganese Oxide And Amino Acids

With the improvement of people’s living standard,people’s requirements for indoor environment were increasing day by day.The Indoor pollutants that come along with it had become the first issue that people consider.Among the numerous indoor pollutants,formaldehyde,as a kind of indoor pollution with great harmfulness,was paid more attention to.How to effectively remove indoor formaldehyde had become a research hotspot in the field of air purification.At present,there were many ways to remove formaldehyde in the market,among which the use of environmentally friendly adsorption materials was one of the most popular way to purify formaldehyde.As a biodegradable organic polymer material,Chitosan had been widely used in many fields for its biocompatibility,blood compatibility,safety and microbial degradation.The abundant amino groups in the molecular chain of Chitosan react with Formaldehyde in addition-dehydration reaction,and the final product was Schiff base,which can remove Formaldehyde,but its application in air purification was limited because of the slow reaction process.The related research showed that the inorganic or organic modification of Chitosan can improve its adsorption activity to different pollutants.Therefore,in view of the defects and shortages of the existing Chitosan adsorption materials,the Chitosan complex was prepared by the chelation of transition metals,such as Chitosan,transition metals and amino acids,the removal efficiency of gaseous formaldehyde was studied.In this paper,theoretical analysis and experimental research were carried out to study on formaldehyde removal performance of chitosan fiber loaded manganese oxide and amino acids.Firstly,the preparation of study on formaldehyde removal performance of chitosan fiber loaded manganese oxide and amino acids was pretested,and the variables in the experiment were determined,including the amount of manganese dioxide,amino acid loading mode,amino acid type and loading amount Then,according to the determined parameters,orthogonal experiments were designed to study the effects of the loading amount of manganese dioxide acid,the kinds of amino acids and the loading amount of amino acids on the purification efficiency of formaldehyde and the purification amount of formaldehyde,the best operating condition of purifying formaldehyde was analyzed,and the adsorption kinetic curve was fitted according to the experimental data of purifying Formaldehyde in the optimum operating condition Then,in order to determine the effect of manganese dioxide and glycine addition on the morphology,crystallinity,and functional groups of the materials,the optimum operating conditions and pure Chitosan fiber were tested by SEM,X-ray diffraction and Fourier transform infrared spectra.Finally,the adsorption process of Formaldehyde in the 1m~3 environment chamber was simulated by CFD using the material CS/8.17g-MnO₂/2g-G/1g,the distribution of formaldehyde concentration and velocity in 1m~3 environmental chamber.The results showed that:（1）The loading amount of manganese dioxide had a great influence on the purification of formaldehyde by formaldehyde removal materials.When the loading amount of manganese dioxide increases from 0g,1g and 2g,the formaldehyde removal material prepared by our research group gradually increases the unit formaldehyde purification amount and formaldehyde purification efficiency with the increase of loading amount of manganese dioxide.When the loading amount of manganese dioxide was 2g,the prepared aldehyde removal material CS/8.17g-MnO₂/2g-AA/0g was adsorbed in 1m~3 environmental chamber for 10 h,and the unit formaldehyde purification amount and formaldehyde purification efficiency of CS/8.17g-MnO₂/2g-AA/0g reach the maximum,which were2.733 mg/m~2 and 45.367%respectively.The second was CS/8.17g-MnO₂/1g-AA/0g,and the purification amount of unit formaldehyde was 2.256 mg/m~2;CS/8.17g-MnO₂/0g-AA/0g,the unit formaldehyde purification amount was 1.651mg/m~2.（2）The kinds of amino acids had a great influence on the purification of formaldehyde by aldehyde removal materials.Among them,the unit formaldehyde purification capacity of CS/8.17g-MnO₂/2g-AA/0g was worse than that of aldehyde removal materials loaded with glycine and lysine,which was 2.733 mg/m~2 and the formaldehyde purification efficiency was 45.367%,followed by CS/8.17g-MnO₂/2g-k/1g loaded with lysine,which was 3.221 mg/m~2 and the formaldehyde purification efficiency was 53.578%;The CS/8.17g-MnO₂/2g-G/1g loaded with glycine had the best aldehyde removal effect,the unit formaldehyde purification amount was 5.023 mg/m~2,and the formaldehyde purification efficiency was 83.237%;（3）The amount of amino acid loading had a great influence on the purification of formaldehyde by aldehyde removal materials.CS/8.17g-MnO₂/2g-G/1g had the best formaldehyde purification effect,the formaldehyde purification amount was 5.023 mg/m~2,and the formaldehyde purification efficiency was 83.237%;The second was CS/8.17g-MnO₂/2g-G/2g loaded with 2g glycine,the unit formaldehyde purification amount4.384 mg/m~2,and the formaldehyde purification efficiency was 73.489%;Finally,the loading amount of glycine was 3g CS/8.17g-MnO₂/2g-G/3g,the unit formaldehyde purification amount was 4.233 mg/m~2,and the purification efficiency of formaldehyde was70.543%.（4）According to the orthogonal experimental analysis,CS/8.17g-MnO₂/2g-G/1g had the best aldehyde removal effect.Therefore,the experimental value of formaldehyde concentration change of formaldehyde removal material CS/8.17g-MnO₂/2g-G/1g adsorbed in 1m~3 environmental chamber for 10h was selected to fit the adsorption kinetic model.The results showed that the quasi second-order kinetic model was more in line with the kinetics of formaldehyde adsorption by CS/8.17g-MnO₂/2g-G/1g,indicating that the adsorption was mainly chemical adsorption.（5）The morphology observed by scanning electron microscope（SEM）showed that the surface of pure chitosan fiber was smooth and the fibers were loosely arranged.CS/8.17g-MnO₂/2g-G/1g after loading manganese dioxide and glycine,the single chitosan fiber was rough.It could be clearly seen that chitosan was attached to the surface in the form of block colloid,with loose structure,layered arrangement and certain pores.This showed that manganese dioxide and glycine were better loaded on chitosan fiber.（6）Fourier transform infrared spectroscopy analysis showed that there were two small N-H stretching vibration peaks at 1587cm^-1 of pure chitosan fiber（CS/8.17g-MnO₂/0g-AA/0g）.At the same wavelength,CS/8.17g-MnO₂/2g-G/1g stretching vibration peak became one and the stretching vibration peak increases,which indicates that there was no chemical reaction after loading glycine and the number of amino groups increases after loading;Compared with the infrared spectrum curve before loading,the CS/8.17g-MnO₂/2g-G/1g curve after loading had a new characteristic absorption peak at 567 cm^-1,which was caused by Mn-O stretching vibration.Therefore,it can be seen that manganese had successfully compounded into chitosan.There was no chemical reaction in the loading process.Glycine and manganese dioxide were physically loaded on chitosan fibers.（7）The X-ray diffraction spectrum analysis showed that the diffraction peak intensity of CS/8.17g-MnO₂/2g-G/1g was higher than that of CS/8.17g-MnO₂/0g-AA/0g,and the crystallinity of CS/8.17g-MnO₂/2g-G/1g was higher.This was mainly because when CS/8.17g-MnO₂/2g-G/1g was loaded with glycine,the drying will precipitate and crystallize the liquid glycine,resulting in the enhancement of the crystallization degree of CS/8.17g-MnO₂/2g-G/1g composite fiber.（8）The method of numerical simulation was adopted to explore the adsorption capacity of formaldehyde removal material CS/8.17g-MnO₂/2g-g/1g in 1m~3 Environmental Chamber,and the distribution of formaldehyde concentration and air velocity in 1m~3environmental chamber were calculated and analyzed,the results showed that the mass fraction and velocity distribution of Formaldehyde in 1m~3 Environment Chamber were relatively uniform.