Study On The Preparation And Application Of Polysaccharides-based Carbon Microspheres

Carbon microspheres（CMSs）are zero-dimensional carbon materials with a cage-like structure and regular morphology.In addition,it shows excellent thermal conductivity,good heat resistance,excellent electrical conductivity,stable physical and chemical properties,etc.Thus,many attentions are attracted on it.Functionalized carbon microspheres also exhibit some unique electrical,magnetic,chemical,catalytic properties and optical properties.Because of these superior properties,carbon microspheres are widely used in many fields such as physics,biology,materials science,chemical industry,catalyst carrier,adsorption carrier and so on.Combining carbon microsphere method with Fenton technology,advanced oxidation technologies（AOPs）,shows great advantages in the field of degradation of organic pollutants in wastewater.Therefore,new ideas are provided for organic wastewater treatment processes.In this paper,soluble starch is used as the carbon source to prepare starch-based carbon microspheres with uniform particle size by hydrothermal method.The influence of the amount of starch,hydrothermal time,and hydrothermal temperature on the morphology of the carbon microspheres in the preparation process is discussed.Then,Fe₃O₄ was used as the magnetizer to prepare magnetic carbon microspheres with uniform particle size by co-hydrothermal method.The influence of the amount of the magnetizer on the morphology and particle size of the carbon microspheres was discussed,and the prepared magnetic carbon microspheres are used as Fenton reagent catalysts to degrade phenol.The effects of reaction time,reaction temperature,reaction p H,and H₂O₂dosage on the catalytic performance are discussed.In addition,this article also explores the preparation of other metal particles and silver nanoparticles on carbon microspheres.Ag/CMSs composite microspheres are also investigated in the catalytic degradation of methylene blue solution.The main research results are as follows:（1）A certain amount of soluble starch was mixed with deionized water and gelatinize in a beaker,then the mixture was placed into a teflon liner,heated at 200℃for 12 h.After cooling to room temperature,washed with deionized water and ethanol,and dried,and then starch-based carbon microspheres with good dispersibility and uniform particle size can be obtained.（2）A certain amount of FeCl₃·6H₂O,NaAc and polyethylene glycol was mixed well with a certain volume of ethylene glycol in a beaker,then react at a certain temperature by hydrothermal method to prepare nano-Fe₃O₄ particles.A certain amount of prepared Fe₃O₄ particles and soluble starch was mixed with deionized water in a beaker,then the mixture was placed into a teflon liner after gelatinization,heated at 200℃for 12 h.After cooling to room temperature,washed with deionized water and ethanol,and dried,and then magnetic carbon microspheres with good dispersibility and magnetic response performance can be obtained.（3）Using magnetic carbon microspheres as a catalyst,combined with H₂O₂ as an oxidizing agent,Fenton reagent was used to explore the optimal conditions for oxidative decomposition of phenol solution.It was found that when the amount of H₂O₂ was 3 ml,the p H was 3.0,the reaction time was 12 h,and the reaction temperature was 40℃,the best removal rate was 93.7%.（4）A certain amount of prepared starch-based carbon microspheres was mixed with silver ammonia solution in a beaker,then whisked 1 h,added a certain amount of PVP and a certain volume of diethanolamine,heated at 70℃for 8 h.It was found when the amount of diethanolamine is 3 ml,the loading of nano-silver on the surface of nano-Ag carbon microspheres（Ag/CMSs）is uniform,and the efficiency of catalyzing Na BH₄ to degrade methylene blue（MB）can reach 100%within 25 min.