Supercritical carbon dioxide has replaced many liquid organic solvents in industry due to its tunable solvent properties, environmental friendliness, and easily achievable critical parameters. The unique properties of supercritical fluids in general, such as gas-like diffusivity and zero surface tension, make them particularly applicable to the field of conservation. This presentation reports o...

INTRODUCTION A sol-gel preparation involves f m t the formation of a sol, which is a suspension of solid particles in a liquid, then of a gel, which is a diphasic material with a solid encapsulating a liquid. The liquid can be removed from a gel by either conventional drying (such as by using an oven) to obtain a plojiict kLown as e xercgel, or hy drying with supercritical extraction (often ref...

Nanostructured silica based xerogels and aerogels are prepared by sol-gel technology, using methyltrimethoxysilane as precursor. The influence of the drying method and conditions on the microstructure of the obtained materials is investigated, since the drying stage has a critical influence on their porosity. Two types of drying methods were used: atmospheric pressure drying (evaporative), to p...

Pr and Nd co-doped Ce-Zr oxide solid solutions (CZPN) were prepared using co-precipitation and microemulsion methods. It is found that only using supercritical CO(2) drying can result in a significant improvement of specific surface area and oxygen storage capacity at lower temperatures for CZPN after aging at 1000°C for 12 h in comparison with those using conventional air drying and even super...

Five different procedures commonly used to rinse and dry released microstructures are compared: evaporation drying with deionized (DI) water or methanol, sublimation drying with t-butyl alcohol orp-dichlorobenzene, and supercritical drying with COz. For objectivecomparison, identical test structures, made by the MCNC Multi-User EMS Processes (MUMPS), are used in evaluating the drying techniques...

Essential oils have important commercial applications as preservatives and flavours, and more recently as natural antimicrobial agents. These applications require a suitable formulation constituted by biodegradable compounds that protect the essential oil from degradation and evaporation at the same time that allows for a sustained release. Microcapsules of biopolymers loaded with essential oil...

The work is based on the drying of PVDF-HFP gels with a procedure assisted by supercritical CO2 to obtain nano-sized porous membranes at high quality/low cost ratio. Poly(vinylidene fluoride) (PVDF) as homopolymer or copolymer with hexafluoropropylene (PVDF-HFP) is a very interesting material largely used in catalytic membrane reactors, chemical and biomedical applications and various filtratio...

Aerogels of layered double hydroxides were prepared by a simple and eco-friendly method involving a quick coprecipitation followed by supercritical CO(2) drying. Such aerogels display high surface areas and enhanced adsorption behavior.

Robust and highly effective Fe-substituted and non-substituted La-Hexaaluminate methane combustion catalysts have been prepared via coprecipitation in "water-pools" of Water/Oil microemulsions with dual nonionic surfactants, followed by ethanol supercritical drying and post-annealing.

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...