mass transfer limitations

Mass transfer limitations occur when the movement of substances, such as gases, liquids, or nutrients, between different areas slows down and becomes a bottleneck in a process. For example, in a chemical reactor, if reactants can't diffuse quickly enough to the reaction site or products can't escape efficiently, the overall reaction rate decreases. This happens because the rate of transfer of substances across boundaries or interfaces is slower than the chemical reaction itself. Essentially, the process is limited by how fast substances can physically move, rather than how quickly they react chemically.