Laboratory chemical transport is a physical process that occurs in liquids and gases. It is the movement of substances from one area to another within a given substance via diffusion, as opposed to passive transport, which involves no energy being used.
transporte de sustancias químicas may be initiated by a variety of different mechanisms including flashing vaporization, evaporation and collisions with gas molecules or other particles where energy is exchanged.
Diffusion is the transport of substances in a fluid by means of random motion. The substance moves from areas of high concentration to areas of low concentration. Examples include the movement of oxygen from an area with high concentration to an area with low concentration and vice versa for carbon dioxide, and movement of water molecules down a slope due to gravitational pull.
Shear-induced diffusion occurs when plasma or blood flow shear forces are used for mixing purposes. This is a similar process to diffusion of gases and liquids, but the substances involved are proteins, colloids and large polymer molecules. The proteins can form thicker layers of tiny particles or smaller globules of protein that allows for the transport of small molecules such as oxygen.
Colloidal systems have particles larger than the interstitial space between them. These particles have hydrophobic properties, which means they do not mix with water. This characteristic makes colloids more difficult to move because these systems use more energy to transport substances such as oxygen and nitrogen.
Decanting occurs when material is moved by the application of a higher pressure to the bottom of a vessel or container. This may be caused by moving liquids from one height to another or expelling gases from a solution.
Film coalescing is essentially when two liquids are combined and form a polymer film between them. The two liquids do not mix, but remain separate until two films come into contact with each other and solidify into one film. This process is similar to a colloid system and can be applied to gases and liquids alike, but the two liquids combine into one polymer film.
The dispersion of fluids is caused by the random motion of particles within the liquid or gas itself. The physical force that causes dispersion to occur is called shear forces. These forces cause particles within a liquid or gas to randomly move causing them to dissolve into each other in order for those liquids or gases to mix.