نتایج جستجو برای: supercritical co2
تعداد نتایج: 79357 فیلتر نتایج به سال:
Fabrication of monodisperse pure silica and core-shell nanospheres (Fe2O3@SiO2 and Fe2O3/QD@SiO2) was done in straight forward one-pot method combining sol-gel chemistry and supercritical fluids. For the core-shell materials, preformed nanoparticles stabilized in hexane were dispersed in a sol containing a silicon alkoxide, water and acetone as the solvent. The precursor solution was introduced...
Venous catheters are important medical devices which are more and more employed in medical treatment. After use, they are currently not re-used, a practice which is very expensive due to their cost. For this reason it is very interesting to be able to set up a sterilizing technology that permit to re-use them without changing their physical properties and the microbial adhesion. The methods usu...
Supercritical (sc) CO2 is by far the most commonly used supercritical fluid. Reasons for this are that it is inexpensive, non-toxic, has low critical constants (Tc = 304.20 K, Pc = 72.8 bar) and is environmentally benign. The major problem encountered when using sc CO2 is the low solubility of polar solutes. Hydrofluorocarbon (HFC) solvents such as difluoromethane (HFC 32) and 1,1,1,2-terafluor...
Due to high surface area, low density, open pore structure and excellent insulation properties aerogels were intensively investigated in the past decades for diverse range of applications. The state of the art of aerogel production by supercritical drying is to produce monolithic aerogel, where the sol is aged in molds and dried by extraction with supercritical CO2. Aerogels in form of spherica...
As the development of the natural medicine, the glycyrrhizin extracted from the licorice root was found to have potential therapeutic value in the treatment of several diseases, especially available for anti-SARS virus . Therefore, the purpose of this work was to find an optimal method to extract and refine the glycyrrhizin. In this work, the extraction of glycyrrhizin by means of organic solve...
Supercritical fluid extraction was used to extract the alkaloid N-[7-(3',4'-methylenedioxyphenyl)-2(Z),4(Z)-heptadienoyl]pyrrolidine from leaves of Piper amalago L. A three-level orthogonal array design matrix, OAD OA9(34), was used for optimization of the parameters of supercritical extraction of the alkaloid, employing supercritical carbon dioxide: extraction time (20, 40, and 60 min), temper...
Natural polymers, such as alginate and gelatin, can be used to produce scaffolds for tissue engineering applications; but, their mechanical and biochemical performance should be improved. A possible solution to obtain this result, is the generation of multi-component scaffolds, by blending two or more polymers. One way to realize it, is the formation of an interpenetrating polymer network (IPN)...
Aerogels are three-dimensional ultra-light porous structures whose characteristics make them exciting candidates for research, development and commercialization leading to a broad scope of applications ranging from insulation and catalysis to regenerative medicine and pharmaceuticals. Biopolymers have recently entered the aerogel foray. In order to fully realize their potential, progressive str...
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