Eumelanin Coating of Silica Aerogel by Supercritical Carbon Dioxide Deposition of a 5,6-Dihydroxyindole Thin Film

Eumelanin integration in silica aerogel (SA) was achieved via supercritical adsorption of 5,6-dyhydroxyindole (DHI) from CO2. Notably, after the supercritical treatment, DHI evolved towards spontaneous polymerization, which resulted in uniform pigment development over the SA. The new material was characterized for its morphological and physicochemical properties, disclosing the formation of a eumelanin-like coating, as confirmed by UV–vis and electron paramagnetic resonance (EPR) spectroscopy.

Characterization of Ketoprofen/Methyl-β-Cyclodextrin Complexes Prepared Using Supercritical Carbon Dioxide

Complexes of methyl-β-cyclodextrin and ketoprofen, a crystalline anti-inflammatory drug with poor water solubility, have been prepared for the first time in the presence of supercritical CO2at 40°C and 20 MPa. The supercritical treatment allows these pharmaceutical formulations to be prepared without the use of any auxiliary agents or organic solvents. The treated samples were characterized through differential scanning calorimetry, X-ray diffractometry, and the Fourier transform infrared spectroscopy to exclude the presence of crystalline drug and check the formation of the complexes. The increase of the drug dissolution rate was investigated performing in vitro release tests in aqueous solutions. The results showed that the supercritical treatment can be an efficient method to obtain inclusion complexes with enhanced release kinetics. The operating methods of the release tests, that is, the “tablet method” or the “dispersed amount method,” affected both the dissolution rate and its dependence on the drug amount in the samples. On the contrary, the variation of the pH of the dissolution medium did not show any effect on the release rate of the supercritical complexes.

Preparation and Photoactivity of Titanium Dioxide-Coated Carbon Felt Using Supercritical Carbon Dioxide

TiO2–coated carbon felt (TCF) was prepared via a supercritical treatment with titanium tetraisopropoxide (TTIP) and different carbon felt as a precursor and support, respectively. The TCF samples with different carbon felts were characterized by X-ray diffraction, scanning electron microscopy, UV-VIS spectroscopy, particle size analyzer and BET surface area. The photocatalytic activities of samples were evaluated by congo red (CR) degradation. The result reveals that all the three samples show much higher photoactivity than the commercial P25. The activity order of the three samples is TCF1< TCF2 < TCF3. The photoactivity is strongly dependent on the surface area and the crystallite size: the larger the surface area and the smaller the crystallites, the higher the efficacy of photocatalytic degradation. The optimal photocatalytic condition is a CR concentration of 45 mg/l at pH 7.

Wood solubilization and depolymerization by supercritical methanol. Part 2: Analysis of methanol soluble compounds

Methanol treatment of ponderosa pine wood was performed in a batch reactor at temperatures close to and above the critical points of methanol (238°C and 8.3 MPa) to induce wood degradation into its monomeric and oligomeric components. The resultant methanol soluble and insoluble residues and gases were collected. The volatile components of the liquid and gaseous fractions were analyzed by GC-MS. The gases consisted mostly of carbon dioxide and simple aliphatic hydrocarbons. The non-volatile methanol soluble components were analyzed by HPLC and size exclusion chromatography. The mixture was found to be promising as a source of raw materials for fuel and chemical manufacturing. It consists of a blend of carbohydrate and lignin derived compounds and extractives in varying concentrations depending on the reaction conditions. More extractive compounds were found in the subcritical runs. In mild supercritical conditions the yield of lignin monomers and oligomers was increased, while under severe supercritical treatment, lignin and carbohydrate derived compounds were prevalent.

The Design of Supercritical Liquid Pipe for Organic Material Treatment

The supercritical liquid discovered in 1821, the specific character was known for many years. However, it began to be used industrially in Japan after the oil shock of the second half of the 1970s. Development of the process which extracts the high ingredient of added value focusing on fields, such as food and medical supplies, using the super-criticality CO2 was furthered at first in Germany. The supercritical water attracts attention with a rise of the concern of the latest resources problem or an environmental problem. Moreover, the process development such as recycling, decomposition of dioxin and PCB and oilizing and monomerizing of a waste plastic have been active. In recent years, use of the woody biomass is briskly performed on Europe. Since there is the woody biomass abundantly, it tends to go into a hand. In this paper, the supercritical liquid is described briefly. Next, the experiment of supercritical treatment of wood is described. And finally, we proposed using the explosive welding technique for the development of pressure vessel and performed the numerical simulation.