Dissertation > Excellent graduate degree dissertation topics show

Preparation of Nanoparticals with Assistance of Supercritical CO2

Author: NiuAPing
Tutor: XuQun
School: Zhengzhou University
Course: Materials Science
Keywords: Nanomaterial Supercritical CO2 Precursor ID carbon nanomaterials Antibacterial
CLC: TB383.1
Type: Master's thesis
Year: 2010
Downloads: 79
Quote: 0
Read: Download Dissertation

Abstract


Nanomaterial is one of the most important scientifical discoveries and have become research highlight of many science in recent years. Because its small size, large surface curvature and specific surface area, nanomaterial possesses bulk effect, surface effect, quantum size effect, macroscopic quantum tunneling effect, specific optical absorption behavior, electro chemical property and so on, which made nanomaterial present a series of excellent properties in photics, electricity, thermodynamics, chemical reaction and so on. There are many methods which may be used to prepare nanomaterial, but utilizing surpercritical fliud to prepare nanomaterial is a green and environmental method. Surpercritical fliud have adjustability, lower surface tension, perfect surface wetting properties, high diffusivity, so these properies make surpercritical fliud become a good medium in synthetizing and preparing nanomaterial. Nanopartical obtained by supercritical fluid technology possesses small grain size, narrow size distribution, high specific surface. Moreover, the penetrability and transfer effect of surpercritical fliud make active object evenly distribute on the surface of carrier and present high catalytic active. Therefore, the main content of my research subject is to prepare nanopartical and its composite, which is showed as follows:1. Preparation of TiO2 nanocrystals:TiO2 nanoparticals have much merit such as nontoxic, steady photochemical property, high chemical activity, good dispersivity etc, so it can be acted as carrier of many material, for example ceramicmaterial, inorganic membrane, sensor, solar cell materials, and catalyst etc. For these reason, we want to prepare TiO2 nanocrystals by the dissolubility and carrying capable of SC CO2 for precursor:SC CO2 can carry precursor into polystyrene (PS) microspheres swelled by SC CO2 and PS-DVB microspheres can be used as the confined space of tetrabutyl titanate hydrolysis. TiO2 nanocrystals were formed after hydrolysis and calcination. Transmition electron microscope (TEM) showed the morphology of TiO2 nanocrystals and X-ray diffraction (XRD) indicated that TiO2 nanocrystals have been formed. The formation mechanism of TiO2 nanocrystals was also proposed. 2. Fabrication of 1D carbon material/Ag nanomaterials:Silver nanoparticals have been extensively researched in catalyst industry and the field of medicine due to its unique performance. 1D carbon nanomaterials have specific physical and chemical performance, so it can be used the supporting matrix to form one-dimensional/ zero-dimensional carbon material composites which have tremendous application foreground. We prepared 1D carbon materials/Ag nanocomposites by the antisolvent function of SC CO2. Silver nitrate (AgNO3) was used as the salt precursor, glucose as the reducing agent and ethonal as cosolvent, and silver composites were formed with the assistance of SC CO2. The effect of different pressures and temperatures on the formation of nanoparticle was studied. Meanwhile we also discussed the effect of the matrix on the size and shape of nanoparticals. UV-Vis and XRD demonstrated the formation of silver nanocrystals. TEM showed that 1D carbon materials/Ag nanocomposites obtained under 12MPa/65℃possess the best assembled structure. The as prepared nanocomposites have good antibacterial activity.

Related Dissertations

  1. Study on the Syntheses and Antibacterial Acticity of Metal Organic Complexes Built from Three Carboxylate Ligands,O621.13
  2. The Drying of Tilapia Fillet Using Supercritical Carbon Dioxide,TS254.4
  3. Study on Phylogenetic Diversity and Bioactivity of Symbiotic Fungi of Coral,R284
  4. Properties and Application Research of Multi-Antibacterial Polyamide Fibers,TQ342.1
  5. Prokaryotic Expression and Purification of Human Beta-Defensin-9,Q78
  6. The Supercritical Carbon Dioxide Extraction and Functional Quality Evaluation of Camellia Seed Oil,TS225.16
  7. Study of Isolation and Identification on Antimicrobial Substances Produced by Lactobacillus Acidophilus NX2-6,TS201.3
  8. Some Pharmacology and Toxicity of Three Prescriptions from Chinese Veterinary Pharmacopoeia,S859.5
  9. Study on the Enrichment of Antimicrobial Peptides and Purification Technology in Wheat Germ,TQ936.16
  10. Study on Screening of Bacterial Quorum Sensing from Plant Extraction and Their Inhibitions on Biofilm Formation,Q93
  11. Development of Functional Automotive Interior Textiles,TS106.6
  12. Initial Studies on the Antibacterical Activity in Vitro and the Safety Evaluation of Propolis Extraction,R285
  13. Study on the Screening of Doramectin-producing Strains by Nitrogen Ion Implantation and Optimization of Fermentation,S859.79
  14. Study on Transformation and Biosynthesis of Saikosaponin in Adventitious Root Culture of Bupleurum Chinense DC.,R284
  15. Oxya endogenous inhibitory protein isolates SDLH feasibility study as a preservative,TS202.3
  16. High glucose in human umbilical vein endothelial cells expression of renin precursor,R543.5
  17. More than enough calcium and magnesium metal ligand complexes Synthesis, Structural Characterization and Antibacterial Activity,O641.4
  18. Schiff base Synthesis, Characterization and Antibacterial Properties,O641.4
  19. Plateau rape pollen extraction and analysis of fatty acids,S896.4
  20. Special morphology precursor synthesis route inorganic oxide,TB383.1
  21. To Explore the Value of Plasma NT-proBNP and Hypersensitive C-reactive Protein in Evaluating the Prognosis of the Patients with Acute Coronary Syndrome,R541.4

CLC: > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials
© 2012 www.DissertationTopic.Net  Mobile