Study On The Recovery And Separation Of Natural Pigments In Plant Waste By Silicon-based Nanocomposite Adsorption Materials

With the continuous improvement of people’s living standards,the demand for health is increasingly valued.As a widely used substance in the fields of food,cosmetics,and healthcare products,the demands of natural pigments are increasing in the market.At the same time,a large amount of plant waste from human daily lives was discarded which contained high value natural pigments.In this study,berberine in natural pigments was selected as the research object,and berberine in solution was separated by extraction and adsorption methods.Preparation of functional sorbents for efficient adsorption of berberine is the focus of this study.In this thesis,a variety of modified silicon based composites have been studied using activated column chromatography silica gel as a matrix and continuously modifying its surface.The materials were characterized using infrared spectroscopy,field emission scanning electron microscopy,and EDS elemental analysis,and the adsorption mechanism of each adsorbent was thoroughly studied.The results showed that among a series of ionic liquid modified silica gel materials,the adsorption of berberine has an enhanced ability,and within a certain range,the adsorption effect will be improved as the length of the carbon chain increasing.The data showed that under the condition of equal mass adsorbent,the adsorption concentration of berberine on imidazole modified silica gel material（Si O₂-IM）was 0.001mg/m L,while the adsorption concentration of butyl imidazole modified silica gel material（Si O₂-BIM）was 0.005mg/m L.Aminopropylimidazole ionic liquid modified silica gel not only obtained a high adsorption efficiency,but also indicated that the amino group can serve as a bridge for modification and continue to modify silicon based materials.In functionalized magnetic ionic liquid modified silica gel,spherical particles Fe₃O₄@Si O₂,chain shaped Fe₃O₄@Si O₂,spherical Fe₃O₄@Si O₂@IL,and chain Fe₃O₄@Si O₂@IL-C adsorbent were prepared by gel coating and magnetic field induction.In the adsorption experiment,the maximum adsorption capacity of several materials for berberine and the adsorption effect were studied under the factors of adsorption time,adsorption temperature,solution p H,and solution salt solution concentration.The optimal adsorption conditions for a chain shape Fe₃O₄@Si O₂@IL-C adsorbent was:adsorption time=3h,adsorption temperature=25℃,p H=3,and salt solution concentration=0.90%.When the optimized condition was applied in the adsorption of deteriorated berberine waste solution,it was found that the adsorption concentration of berberine reached 99.48%.In the experiments of modifying silica gel with metal organic frameworks and ionic liquids,chemical bonding method and physical impregnation method have approved Si O₂-NH₂,Si O₂-NH-COOH,Si O₂-NH-COOH-UIO-66,Si O₂-IL-NH₂,Si O₂-IL-NH-COOH,Si O₂-IL-NH-COOH-UIO-66,etc.Experiments on the maximum adsorption capacity of several chemically synthesized adsorbents were conducted,representative Si O₂-NH-COOH-UIO-66 and Si O₂-IL-NH-COOH-UIO-66 were selected.Single factor test on adsorption efficiency and the kinetics and adsorption isotherms models on Si O₂-IL-NH-COOH-UIO-66 were studied.Results showed that the maximum adsorption capacity of a unit mass adsorbent on the target substance was0.0022mg/m L and the adsorption process of berberine by this adsorbent was closer to the quasi second order kinetic model and more consistent with the Langmuir adsorption isotherm model.When the sorbent was applied in expired drug solutions under the optimized conditions,99.70%of berberine was recovered.In the mechanism study,characterization and adsorption experiments of main binding materials,the mechanism of several adsorbents was explored.It was found that the adsorption process was due to the formation of hydrogen bonds,π-πconjugation,electrostatic interaction between ions,hydrophobic interaction,between the amino and carboxyl groups on the surface of the adsorbent,ionic liquids,UIO-66,and the target molecules of berberine.It can effectively improve the adsorption performance of materials by enhancing several forces.In this thesis,the research on new materials of natural adsorbent,responding to the requirements of the times,expected to transform theoretical knowledge into practical achievements.Under the concept of green and environmental protection,recycling waste plant resources,not only solves the problem of environmental pollution,but also creates new social value.