Preparation Of Biomass Micro-nano Composite Materials And Tellurium Separation Properties

In recent years,the photovoltaic industry as an important branch of clean energy,has been rapid development under the rapid innovation of new technology and the rapid expansion of the market demand.However,a large number of waste photovoltaic waste has also aroused people’s alarm,especially the discarded thin film solar cells with tellurium compounds added randomly,which not only causes a waste of resources,but also endangers people’s health.Therefore,recycling tellurium from discarded thin-film solar cell materials has important economic and environmental value.Compared with the traditional roasting method,chemical precipitation method,electrolytic refining method and microbial treatment method,the adsorption has the advantages of short extraction process,low pollution and low energy consumption.Porous materials using biomass as raw materials have attracted extensive attention as ideal adsorption materials because of their unique physical and chemical properties（ultra-low density,high specific surface area,degradability and biocompatibility etc.）.Therefore,in this paper,cellulose is selected as the raw material to prepare various types of cellulose materials,and the micro-nano structure is constructed by introducing inorganic nanoparticles for the recycling of tellurium,which is specifically divided into the following three parts.（1）Preparation of NZVI/CFAs for tellurium separation propertiesUsing agricultural waste corn bracts as raw material,pure cellulose was extracted by simple acid-base treatment and use sodium chlorite and sodium hydroxide to remove lignin,hemicellulose,pectin and other components in the raw materials to extract pure fiber vegetarian.By freeze-drying technology,CFAs was prepared,and on this basis,NZVI/CFAs was prepared by liquid-phase reduction method.The reaction time,temperature,initial concentration and interference ions were studied in batch.It was found that the kinetics of NZVI/CFAs was consistent with the pseudo-first-order model（R²=0.9989）and Langmuir isothermal model（R²=0.9972）,indicating that the adsorption process of NZVI/CFAs was monolayer adsorption.The activation energy（Ea）of 303 K to 333 K is 57.40 k J/mol,indicating that the adsorption of tellurium by NZVI/CFAs is mainly redox chemisorption.（2）Preparation of nano-flowered magnesia-alumina spinel/cellulose aerogel for tellurium adsorption propertiesMagnesia-alumina spinel/cellulose aerogel（Mg-Al spinel/CAs）composites were prepared by organically combining the preparation of inorganic ceramic materials with the biological template technology.Nano-flowered Mg Al₂O₄ not only effectively solves the agglomeration problem of spinel powder,but also reduces the sintering temperature of Mg Al₂O₄ from about 1300℃to 950℃.The results show that the maximum adsorption capacity of Mg-Al spinel/CAs composite for tellurium is 69.28mg/g,which has good chemical stability and recycling ability.The adsorption process of Mg-Al spinel/CAs was consistent with Langmuir and pseudo-second-order kinetic models.The corresponding correlation coefficients R² were 0.9960 and 0.9952,respectively.（3）Preparation of Mn O₂ microspheres modified cellulose membrane for tellurium separation propertiesUsing cotton as raw material from a wide range of sources,cellulose was dissolved and regenerated,modified with Mn O₂ microspheres,and coated to prepare Mn O₂regenerated cellulose membrane（Mn O₂ RCM）.The Mn O₂ RCM with adjustable pore size and tensile strength can realize the dynamic separation of tellurium on the basis of retaining the original structure and characteristics of cellulose.The maximum adsorption capacity of Mn O₂ RCM was 102.17 mg/g.In the range of p H 2-9,the adsorption capacity can be high,and the adsorption capacity can still reach 77.41mg/g at p H=2,indicating that the material has good acid resistance.