You may not realize it, but there are different types of lab water. Some people think that all water is the same, but that is not the case. Every kind of lab water differs according to its level of purity. There are different types and grades of purity that categorize water.
You should be using the purest water for operations and procedures with high sensitivity to impurities and contaminants. This is because contact with the pollutants and contaminants will compromise the outcome of the process. You cannot use the highest purity all the 
time because obtaining it is a painstaking and costly method.
Moreover, some experiments and operations do not require ultra-pure water. Thus, obtaining it will be unnecessary. There are many different ways to obtain chemically pure water in the laboratory. One of the most common ways to purify the water in the lab is through distillation. Other methods include reverse osmosis, deionization, and dialysis.
Dialysis
Using the dialysis method, you can separate small and large particles from the water. This method is more commonly used to separate protein particles from water. This technique is often a part of a more extensive process for water treatment.
This method works on many fractions of purification. It first diffuses the solutes by passing the water fluid through a permeable membrane, or in this case, a dialysis bag. This bag contains a carbohydrate solution, and you have to place it inside water.
Once you do that, you have to wait for the osmosis process to come into fruition. In the osmosis process, particles inside water move from a higher concentration region to a lower concentration region. Therefore, molecules in the surrounding water areee big enough to permeate through the dialysis bag.
According to concentration levels, they either enter into or out of the bag. This process is more frequently used at a laboratory scale to obtain pure water, free from any salt concentration.
The Process
Initially, a semi-permeable membrane contains the target protein which is to be placed into the water container. This allows the salt to move through the tubing from higher concentration to lower with the help of diffusion.
As the solution inside the dialysis tubing falls, the concentration of the salts increases in the tubing. Continuously performing this procedure leads to diafiltration. The water then undergoes an ultrafiltration process, which helps eradicate all the harmful salts from the water.
Industrial Use-cases
Dialysis uses a membrane-based approach, along with the principles of the concentration gradient to purify water. Unlike other purification methods, it does not utilize a pressure-driven process. This is why the process is slower than others.
It was the first membrane-driven process used at an industrial level. Overall, the functionality of microporous membranes inside a solution that exhibits a clear concentration difference can lead to the separation of salts and other large contaminants.
Diffusion Coefficients and Reverse Osmosis
Dialysis is a purification technique that encourages the transfer of small molecules through a semi porous membrane. Much like reverse osmosis technique, molecules with high diffusion coefficients will separate in this process, regardless of their size.
Final Takeaway
To this day, dialysis continues to meet industrial applications around the world. It is especially most prominent in biotechnology and life sciences. With the help of the dialysis process, you can separate delicate substances without damaging them. Moreover, despite a low shear flow and slow process, dialysis helps separate small and large molecules effectively without a pressure gradient.
