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In this paper data regarding the utilization of aerogel as a promising material for thermal insulation of the residential and commercial buildings are presented. Also, research work and developments in synthesis, properties and characterization of silica aerogels will be addressed. Aerogel is a synthetic porous ultralight material derived from a gel in which the liquid component of the gel has been replaced with a gas. The result is a solid with extremely low density and low thermal conductivity. Sol-gel is the most used method of preparation. Aerogel melts at 1200ºC and the thermal conductivity is almost 0. Is a solid material with the smallest density because contains about 99.8% air. This material has almost unlimited potential, believing that they might find application in most human activities and areas. Aerogel insulation is a good choice because nearly neutralizes all three methods of heat transfer: convection, conduction and radiation. The resistance to convective transfer is given by the fact that air does not circulate in the material structure. The resistance to thermal transfer by conduction is given by the majority of gaseous components. If using a carbon based gel, a high resistance to radiation transfer is obtained. Therefore, the most used aerogel for thermal insulation is the silica aerogel with carbon as nanostructured material. The high price makes it currently inaccessible and less used material. But, inevitably, the aerogel will quickly become one of the most attractive materials in the future.

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Recently the membrane separation processes have very often been used due to the simplicity and elegance of the selective gas, ions, or molecules transport through a very thin "barrier".Separation and recovery of metals has become very important in the last ten years because of the uncontrolled spread of the substances in the environment. The problem of selective elimination of toxic metallic ions from aqueous solutions followed by their recovery and reuse has a great ecological and economic importance.In this paper, the method of obtaining a new type of activated composite membrane is presented. The membrane obtained is characterised by different modern techniques and its behaviour is tested in the separation processes of metals, such as zinc (Zn), and gallium (Ga), from wastewaters. Metal content is determined by Atomic Absorption Spectroscopy (AAS).