| Ginkgo biloba is a deciduous tree of the genus Ginkgo in the family Ginkgoaceae.It has a beautiful tree shape,plump crown and rich nutritious fruit.It is a high-quality tree with high comprehensive utilization value.In recent years,the development and utilization of active ingredients in extracts from various parts of Ginkgo biloba is one of the research hotspots in the field of medicine.China is rich in ginkgo resources and widely cultivated.A large number of Ginkgo biloba branches resources are produced during the growth and tending process of ginkgo,which are often abandoned because they cannot be reasonably utilized.In order to effectively improve the high-value utilization of Ginkgo biloba branches resources,in this study,Ginkgo biloba branches were used as experimental raw materials,and three solvents,acetone,benzene and ethanol,were used to extract Ginkgo biloba branches.Analysis and testing methods such as gravity,pyrolysis-GC-MS,etc.,analyze the chemical components in Ginkgo biloba branches,and clarify their antioxidant capacity and antibacterial characteristics;use slow pyrolysis method to prepare Ginkgo biloba branches biochar,and carry out nano-magnetic modification.The modified biochar was characterized and analyzed by scanning electron microscope,X-ray diffractometer,specific surface area analyzer,etc.;the adsorption performance and regeneration ability of Ginkgo biloba branches modified biochar on heavy metal lead were analyzed by inductively coupled plasma-optical emission spectrometer.The main findings are as follows:(1)Analysis of group changes before and after extraction of Ginkgo biloba branches.The infrared spectrum peaks of Ginkgo biloba branches powder and its extract were similar,but the intensities of peaks were different.Ginkgo biloba branches powder and its three solvent extracts mainly contained phenols,alcohols,aldehydes,aromatic hydrocarbons,alkanes,olefins and other substances,indicating that the components in Ginkgo biloba branches extract were effectively extracted.(2)Analysis of volatile components in different solvent extracts of Ginkgo biloba branches.The volatile components of Ginkgo biloba branches extracts were analyzed by GC-MS.It was found that the contents of alcohols,phenols and alkanes in the three solvent extracts were higher.The contents of substances in acetone extract from high to low were alcohols(31.95%),phenols(25.01%)and alkanes(24.49%);the order of benzene extracts was alcohols(75.15%),phenols(6.82%),and aromatic hydrocarbons(6.58%);the order of ethanol extract was phenols(55.72%),alcohols(16.13%),esters(4.51%).Chemical raw materials and biomedical materials are more in the volatile components of Ginkgo biloba branches extract,and the content of benzene in Ginkgo biloba branches extract is the highest,which is 56.70% and 27.34%respectively,indicating that the volatile components of Ginkgo biloba branches extract are suitable as chemical raw materials and biomedical raw materials.(3)Analysis of non-volatile constituents of different solvent extracts from Ginkgo biloba branches.The non-volatile components of Ginkgo biloba branches extracts were analyzed by high-resolution liquid mass spectrometry,and it was found that the contents of esters,phenols,acids and alkaloids in the three solvent extracts were higher.The content of substances in the acetone extract from high to low is phenols(51.55%),acids(5.50%),terpenes(5.05%);the order of benzene extracts is phenols(41.67%),ketones(10.26%),esters(8.58%);the order of ethanol extracts was esters(45.72%),alkaloids(18.99%),acids(8.47%).A large number of biomedical substances were found in the non-volatile components of the Ginkgo biloba branches extract,among which the content of biomedical substances in the ethanol extract of ginkgo branch was the highest,reaching 55.08%.The results showed that the nonvolatile components in Ginkgo biloba branches extracts were suitable for use as biopharmaceutical raw materials.(4)Analysis of thermal weight and pyrolysis components of Ginkgo biloba branches.Thermogravimetric curves of four samples were divided into four stages according to the temperature change and weight loss rate during pyrolysis.In the first stage(50 ℃~175 ℃),the mass of the sample decreased slowly due to the precipitation of water on the surface and internal of the Ginkgo biloba branches powder.In the second stage(175 ℃~375 ℃),a complex chemical reaction occurred.The precipitation of a large number of volatile components caused a strong combustion reaction,resulting in a mass loss rate of more than 30%.In the third stage(375 ℃~490 ℃),lignin in Ginkgo biloba branches powder was pyrolyzed to generate a small amount of volatile components and a large number of coke,and the mass loss rate reached more than 25%.The mass loss was mainly due to the combustion quality of coke.Less weight loss occurred in the fourth stage(490 ℃~840 ℃),which may be due to the further combustion of residual coke,resulting in some loss of quality.The results of pyrolysis experiments show that the pyrolysis components of Ginkgo biloba branches powder are rich,including phenols,acids,olefins,aromatic hydrocarbons,alcohols and other compounds.The pyrolysis products are mainly concentrated in the field of chemical raw materials,but also contain a small amount of biological medicine,food flavors and other types of substances.The relative content of pyrolysis components of Ginkgo biloba branches powder after different catalyst treatment has obvious difference.The types of pyrolysis components at 700 ℃ are more abundant,indicating that the content of functional components in pyrolysis products increases with the increase of temperature.(5)Analysis of antioxidant and antibacterial activity of different solvent extracts from Ginkgo biloba branches.DPPH method and ABTS method were used to evaluate the antioxidant capacity of different solvent extracts of Ginkgo biloba branches.The results showed that the antioxidant capacity of Ginkgo biloba branches extracts increased with the increase of concentration,and the acetone extract of Ginkgo biloba had the strongest antioxidant capacity.At the concentration of 40mg/m L,the scavenging rates of acetone extracts from Ginkgo biloba branches on DPPH and ABTS free radicals were 98.39% and 98.33% of those in the Vc control group,respectively.The three solvent extracts of Ginkgo biloba branches had good inhibitory effects on Bacillus subtilis.The acetone extract showed inhibitory effects on Staphylococcus aureus and Escherichia coli,and the diameters of inhibition zones were 8.05 ± 0.22 mm and 7.94 ± 0.09 mm,respectively.The results showed that Ginkgo biloba branches extract had good antioxidant and antibacterial ability.(6)Preparation and structural characterization of Ginkgo biloba branches modified biochar.The average yield of Ginkgo biloba branches biochar was 30.71%,and nano-magnetic biochar was prepared by loading metal iron and sodium carboxymethyl cellulose(CMC)on its surface.The results of infrared spectroscopy showed that the surface functional groups of biochar were also changing during the modification process,and the surface of magnetic biochar had Fe-O functional groups,indicating that the modified biochar composites were loaded with magnetism.The results of scanning electron microscopy showed that the appearance of Fe3O4-RB and CMC-Fe3O4-RB changed significantly compared with those of the untreated Ginkgo biloba branches biochar(RB),and the number of fine particles such as spherical particles on the surface of biochar increased significantly.The energy spectrum analysis further revealed the changes in the content of crystal elements on the surface of modified biochar.In the process of modification,the carbon element in biochar decreased continuously,and the content of oxygen and iron increased continuously.The results of X-ray diffraction show that the crystal diffraction peak of magnetic biochar matches the standard spectrum of Fe3O4,and the prepared biochar has typical graphite-like structure.The results of specific surface area and pore size analysis showed that the specific surface area,pore size and total pore volume of modified biochar were 3.4 times,7.07 times and 2.08 times of the original,respectively.It indicated that the magnetic and CMC loading on the surface of Ginkgo biloba branches biochar was a good and feasible modification method.(7)Adsorption performance and regeneration ability of Ginkgo biloba branches modified biochar for Pb2+.In the Pb2+ adsorption experiment,the adsorption effect of modified biochar CMC-Fe3O4-RB on Pb2+ increased by 34.71%,and the adsorption process of adsorption kinetics experiment followed the pseudo-second-order kinetic model.The Langmuir isotherm model can well reflect the adsorption process of Pb2+by CMC-Fe3O4-RB.After five cycles of regeneration,the adsorption rate of Pb2+ on magnetic ginkgo branch biochar was 52.98% and remained stable,indicating that it had the potential of recycling and could be used as an effective adsorbent for Pb2+removal in aqueous solution.In this study,the solvent extraction method was used to efficiently extract the active components from Ginkgo biloba branches and analyze their biological activities.Strong adsorption and recycling capacity.The above experimental results show that Ginkgo biloba branches contains a variety of antibacterial and antioxidant active components and has the potential to be prepared into high-value modified biochar,which provides a theoretical basis for the multi-level utilization of Ginkgo biloba branches resources. |
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