Why Silica Gel is the Preferred Adsorbent for Chromatography

Chromatography Adsorbents - An Introduction

The chromatography process consists of two phases - the stationary phase placed in the vertical column and the mobile phase, which is placed on top of the same column and then makes it way downward. As the mobile phase moves downwards, different constituents of the mixture will get separated at different levels, thus completing the chromatography process. 

Adsorbents are very important to the chromatography process. They are basically molecular desiccants with high surface density and large surface area. Adsorbents are used in different types of chromatography for absorbing and thus separating, various components of any given mixture. The commonly used adsorbents include Silica Gel, Alumina, Carbon, Magnesium Oxide and different types of carbonates. Each adsorbent brings to the table its own unique characteristics and benefits. 

Why Silica Gel Adsorbents are Important for Chromatography

Silica Gel is one of the most important adsorbents used as the stationary phase in the chromatography process. Among Silica Gel adsorbents, the porous variety is most preferred by the clients. Silica Gel desiccant is known to be an acidic adsorbent and therefore has less polar properties when compared to Activated Alumina. As Silica Gel desiccant is less polar, it will mostly adsorb all the basic compounds present in the mixture. 

The particle size of the Silica Gel is what decides, which chromatography process it will be used for. The particle size is directly proportional to the surface area of the Silica Gel. More surface area translates into more water vapour molecules getting adsorbed. This can be explained with the help of few examples- In normal phase chromatography, non-polar components elute quicker because of the polarity of the Silica Gel adsorbents. In reverse phase chromatography, it is the polar components that elute first as hydrophobic groups get attached to the Silica gel. 

There are many reasons as to why Silica Gel is preferred as the stationary phase. The first and main reason is its high polarity, which can attract water vapour or any other molecules in the shortest time possible. This makes economic sense for clients as they need not spend too much time and money in choosing the stationary phase adsorbent. The second is its large surface area, wherein more molecules can be adsorbed over more area. The third and final reason is its easy availability in the form of beads, balls and granules.

Chromatography- Best Choice For Separating Fine Chemicals

Chromatography – An Introduction

Chromatography is a separation and purification technique mainly used to separate individual components of a mixture so that they can be separately analyzed and researched upon. Chromatography consists of a stationary or solid phase and a mobile or liquid phase. The most commonly used types of Chromatography are Column Chromatography, Thin-Layer Chromatography and Flash Chromatography. All these chromatography methods are designed to cater to different needs of various customers. 

The main applications of Chromatography are in the separation of fine chemicals, differentiation and purification of antibiotics, purification of DNA samples and biomarkers. Read on to find out how chromatography makes the separation process of different fine chemicals a lot more easier.

Chromatography in Separation of Fine Chemicals

Chromatography is very useful in the separation of fine chemicals as this process easily helps segregate the different fine chemicals that make up any mixture. Often people find it very difficult to separate fine chemicals when they are present in small quantities. This is where the process of chromatography proves to be useful. It is the best method available in which small quantities of fine chemical mixture can be separated without any difficulty. 

Another advantage of using Chromatography to separate fine chemicals is that it can be done in very less time. If one opts for this type of purification process, one can be guaranteed of accurate separation of components in the minimum time possible. This can be achieved with flash chromatography. 

One can also make use of the chromatography process to separate fine chemicals, which are very similar in physical appearances and have an almost identical chemical composition. Separating such chemicals becomes very difficult and this is where the role of chromatography becomes important. These fine chemicals cannot be separated by the usual modes of separation.  

The use of Silica Gel Column Chromatography and Flash Chromatography in the separation of fine chemicals has other uses also. It brings down the level of solid consumption, increases the production and purification rate and results in lesser dilution of the product streams. The movement of the mixture through the stationary phase and mobile phase will lead to accurate separation of the fine chemicals as they settle down at different levels based on their solubility.

Four Key Uses of Silica Gel Dehumidification

What is Dehumidification?

Dehumidification is a process by which excess moisture present in the air is removed. Many times air needs to be dehumidified because the presence of water vapour can cause damage to products, packed or otherwise. Dehumidification of the air can be done using three methods- condensation, adsorption and absorption. 

In condensation, moisture is removed by drying the air below the dew point. Following this the water vapour present in the atmosphere is condensed and removed. In adsorption, the water vapour is adsorbed onto the surface of an adsorbent like Silica Gel or Aluminium Oxide. When the adsorbent takes in the moisture, it does not undergo any physical or internal changes. Similar to adsorption, absorption also absorbs the excess moisture in the air. However, in absorption the desiccant undergoes internal as well as external changes. Unlike adsorbents, these desiccants cannot be reused as they have undergone physical changes.  

Silica Gel Dehumidification

Dehumidification using Silica Gel (SiO2) as an adsorbent is known as Silica Gel Dehumidification. In this process, the Silica Gel can adsorb moisture up to nearly 40% of its own weight. The specialty of Silica Gel is that it is highly porous and has a very large surface area. The adsorbent's openings are about 50-70% volume and hence the intake of moisture is quite high. 

The major benefit of using Silica Gel as a dehumidifier is that it can reuse. Silica Gel can be regenerated by heating. Once heated, it will lose all the moisture adsorbed and is ready to be used once again. This is why the use of Silica Gel is said to be economical.

Four Major Uses of Silica Gel Dehumidification

There are many uses of Dehumidification with Silica Gel as an adsorbent. Four of the important ones are listed below:

1) Keep Storage Spaces Dry: Silica Gel dehumidification is very important in keeping storage spaces in houses and warehouses free from moisture. By doing this, goods stored in these spaces will remain unspoilt and have a longer shelf life. 

2) Keep ammunition moisture-free: Dehumidifying using Silica Gel sachets help in keeping guns and other ammunitions free from the ill-effects of excess humidity.

3) Helps electronics function better: When kept alongside electronic equipment like television, computers, VCDs, DVDs, etc., Silica Gel improves their functioning. This is done by adsorbing vapour from the surroundings.

4) Protects outdoor gear: Silica Gel Dehumidifier keeps outdoor equipment like camping gear, fishing rods free of mold, bad odours and mildew. The adsorbent removes excess moisture, which is the main cause of all these problems.