Preparation,Characterization And Catalytic Transesterification Of Pistacia Chinensis Seed Oil By HPW Immobilized On Magnetic Composite Graphene Oxide/Cellulose Microspheres

In this study,a composite microsphere carrier was prepared by using graphene oxide and regenerated cellulose as raw materials for the first time.For the first time,phosphotungstic acid was immobilized on this carrier and magnetic composite graphene oxide/cellulose microsphere-loaded phosphorus was successfully prepared.The catalyst was characterized and applied to the catalytic esterification of Pistacia chinensis seed oil to biodiesel.In addition,the addition of magnetic iron tetroxide enables rapid separation and reuse of phosphotungstic acid catalysts.The specific research results of this study are as follows:1.Preparation and characterization of magnetic composite graphene oxide/cellulose microspheres immobilization phosphotungstic acidUsing graphene oxide with excellent physical and chemical properties and inexpensive,resource-rich,clean and renewable cellulose as raw materials,hot-melt adhesives were used to convert regenerated cellulose to prepare composite graphene oxide cellulose microspheres;triethylenetetramine was used to aminate the composite microspheres;magnetic Fe3O4 particles were prepared on the composite microspheres by coprecipitation method;phosphotungstic acid was immobilized on the carrier materials by chemical immobilization and magnetic composite graphene oxide/cellulose microspheres immobilization phosphotungstic acid catalyst was successfully prepared.In the experiment,the amount of doped graphene oxide was first optimized to obtain the optimum mass percentage of graphene oxide and cellulose.At the same time,the prepared supports and catalysts were characterized by SEM,BET,FTIR and XRD.The results show that comparing with the pure cellulose bare spheres,the doping of graphene oxide changes the structure of the microspheres,and the abundant active functional groups on the graphene oxide play an active role in the amination of the microspheres.2.Established an effective ultrasonic extraction method of P.chinensis seed oilUltrasound-generated cavitation is used to accelerate cell wall crushing and promote the dissolution of fats and oils in solvents.Effective ultrasonic extraction of P.chinensis oilseed oil is achieved.Single factor experiment and response surface analysis method were used to optimize the extraction process of P.chinensis seed oil.Under the condition of n-hexane as extraction solvent,the optimal extraction conditions were determined as follows:Solvent/material ratio:8.7(mL/g)Extraction temperature:64.1 ℃Extraction time:29.5 minParticle size of material:20 meshExtraction power:100 WUnder the optimized extraction conditions,the extraction rate of P.chinensis seed oil can reach 41.2%.The ultrasonic method has the advantages of short extraction time,high extraction efficiency and environmental protection,so it is suitable for highly efficient extraction of P.chinensis seed oil.3.A process for the synthesis of fatty acid methyl ester from Pistacia chinensis seed oil using magnetic composite graphene oxide/cellulose microspheres immobilization phosphotungstic acid was established.After optimization of the catalyst,P.chinensis seed oil was used as raw material,phosphotungstic acid immobilized on magnetic composite graphene oxide/cellulose microspheres as a catalyst and the important parameters in the transesterification process were further optimized.The optimized conditions are as follows:Reaction temperature:80 ℃Alcohol/oil molar ratio:12:1Catalyst dosage:15 wt%Reaction time:8 hUnder the optimal conditions,the yield of fatty acid methyl esters can reach 94%.The reuse experiment of catalyst has shown that the prepared phosphotungstic acid immobilized on magnetic composite graphene oxide/cellulose microspheres are relatively stable.They can be quickly separated under the action of external magnetic fields,and the yield of biodiesel can still reach 80%after 6 cycles of the catalyst.The XRD analysis further demonstrates that phosphotungstic acid can maintain the structural stability on the recovered catalyst comparing to the undoped graphene oxide catalyst.In summary,the present study innovatively incorporated graphene oxide and cellulose into composite microspheres and used it as a phosphotungstic acid carrier for the first time to prepare phosphotungstic acid immobilized on magnetic composite graphene oxide/cellulose microspheres successfully.Based on this study,the synthesis process of fatty acid methyl esters of P.chinensis seed oil catalyzed by phosphotungstic acid immobilized on magnetic composite graphene oxide/cellulose microspheres was established.The method for synthesizing fatty acid methyl esters in this study has the characteristics of high efficiency,environmental protection and environmental-friendly,which lays the foundation for the production of biodiesel from forest seed oil represented by P.chinensis seed oil as raw material oil and supplies new solutions for the competition bettween biodiesel industry and the agriculture and food industries.