| Scutellaria baicalensis resources are widely distributed in all parts of my country.With the development of Scutellaria baicalensis planting,the output of Scutellaria baicalensis has greatly increased.The active substances in Scutellaria baicalensis have a variety of utilization values,and higher requirements are put forward for their quality and extraction technology,and further improve the utilization of Scutellaria baicalensis resources.It is a very meaningful thing to realize the maximum utilization of Scutellaria baicalensis resources with application value.After the extraction of active substances from Scutellaria baicalensis,a large amount of extraction residue will be produced,which will inevitably cause serious environmental pollution if discarded at will.Traditional treatment methods are also difficult to meet environmental protection requirements.Carbon materials prepared from various biological wastes have good surface structure,large specific surface area and abundant pore distribution,and are widely used in adsorption,electrode materials,and carrier materials.Recycling the waste residue after extraction of active ingredients to prepare biomass carbon materials not only reduces the environmental burden,but also realizes more efficient utilization of Scutellaria baicalensis resources.In recent years,the topic of environmental protection has been widely discussed.With the rapid development of industrialization,environmental pollution caused by various industrial products is a serious threat to human life and health.In this study,the dried roots of Scutellaria baicalensis were used as raw materials,and after the active substance baicalin was extracted,the residual residues were recovered to prepare porous carbon materials.On this basis,high-purity baicalein and its metal complexes were prepared.The complex was used as the catalyst to study the photocatalytic degradation of methylene blue dye wastewater,which proved the feasibility of degradation when visible light was used as the light source,and the carbon material of the residue extracted from Scutellaria baicalensis was used as the carrier to support the catalyst,which further improved the photocatalytic efficiency.The main research contents are as follows:(1)Using the dried root of Scutellaria baicalensis as raw material,baicalin was extracted by ethanol heat reflux,and the optimal extraction process conditions and process parameters were optimized and screened as follows: ethanol concentration60 %,extraction temperature 85 ℃,solid-liquid ratio 1:9,extraction The time was2.5 h,and the extraction was performed twice;the yield of crude baicalin was 21.2%,and the content was 40.31%.After repeated tests,the extraction yield and content were stable.Baicalin was purified by alkali-soluble alcohol precipitation and recrystallization.The best purification process was screened and purified: 40% Na OH with a solid-to-liquid ratio of 1:10,adjusting the p H of the solution to 7-8,and dissolving it in a water bath at 60°C for 30 min After centrifugation,collect the supernatant and add an equal amount of 90% ethanol for precipitation for 2 h,filter and wash to neutrality to obtain the preliminary purified product of baicalin,then add100 times the amount of methanol,dissolve in a water bath at 60 °C,filter while hot,and cool The baicalin crystals were precipitated,and the solvent methanol was recovered by rotary evaporation.Utilize HPLC to carry out qualitative and quantitative analysis of baicalin after purification,and prove that the gained is a baicalin product with a purity of 95.45 %.(2)Using the purified baicalin as raw material,the hydrolysis method was used to prepare baicalein,and the optimum baicalein preparation process was screened as follows: hydrochloric acid concentration of 25 %,hydrolysis temperature of 100 ℃,reaction time of 2 h,solid-liquid ratio of 1:50,and the use of ethanol.The obtained baicalein was recrystallized three times,and the purity of the obtained baicalein was98.58% after using HPLC to carry out qualitative and quantitative analysis.And the scavenging effects of baicalin and baicalein on DPPH and lipid peroxy radicals were compared and analyzed,and it was found that baicalin and baicalein had good scavenging effects on both free radicals,and the scavenging effect of baicalin was better than that of baicalin.And the higher the purity,the better the removal effect.(3)Scutellaria baicalensis was recovered and the residue was extracted,and the porous carbon materials were prepared by high temperature carbonization in a tube furnace.The optimal preparation process was found to be activated with 0.5 times the amount of KOH,pre-carbonized at 400 ℃ for 1 h,and carbonized at 800 ℃ for 1 h.The specific capacitance of the carbon material prepared by this process in 0.5 A/g 6M KOH aqueous solution is 223.6 F/g,indicating its good electrochemical performance.Characterization and analysis by Raman,X-ray diffraction and X-ray electron spectroscopy as well as SEM and BET show that the material not only has a large specific surface area(1666.6 cm2/g),but also contains a large number of mesopores and micropores,which can be used as a Excellent adsorbent material,electrode material and catalyst carrier.(4)The metal complexes of baicalein and Cu,Co and Ni were prepared and used as catalysts to study the photocatalytic degradation of simulated methylene blue dye wastewater.It was found that the xenon lamp simulating visible light was used as the light source for methylene blue dye wastewater.The degradation effect of methylene blue wastewater can reach 92.92 % when baicalein-Co is used as a catalyst and 700 W xenon light is illuminated for 2 h.The degradation rate of methylene blue can reach 97.18 % after 1 h. |
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