Dr. Lawrence K Wang and colleagues, authors of numerous books on environmental issues, note that dilute solutions have a lower concentration. Solute solutions have a higher concentration. The necessary concentration of the solution can be determined by the intended application of the solution. The rate of passage through the membrane will be determined by how porous the filtering material is. A fine mesh will result in a solution with fewer impurities. However, the fine filtering material can result in a more dilute solution.
A coarser filtering material can allow more matter to pass through and result in a more solute solution. However, this allows more impurities to pass through as well. As noted previously, the concentration of the solution and acceptable levels of impurities can be determined by the intended application. In organic applications, such as medicine, concentration and purity are both critical.
The flux of a solution follows certain patterns as the material passes through the membrane. A critical factor that will help to determine the behavior of the solution is how how well mixed the material is. Assuming that the material is well mixed, patterns of deposits of impurities upon the membrane can be predicted and fall within acceptable limits. This is especially true of solutions that will be pushed through the membrane at a high rate of flow. The acceptable limits can be maintained by mixing the solution just before passing it through the membrane.
An ideal model of a membrane would indicate that a constant concentration of the solution would be maintained. In reality, several factors can affect the flow of the solution through the membrane. One such factor is inconsistency of the flow across the surface of the membrane. Some areas may become covered with the captured impurities and inhibit the flow of the material. The efficiency of the filtration can be measured by comparing the rate that water should flow through the membrane as compared with the actual flow of the solution.
The physical characteristics of the selected membrane will affect the behavior of a dilute or solute solution. These characteristics include factors other than the size of pores. The flux between dilute and solute solutions can be used to determine the flow rate of membranes for these solutions.