TEORI ADSORPSI

The adsorption theory

this theory is very necessary for someone who pursued the world of higher education as a student majoring in chemical engineering.

Principle

Adsorption

Adsorption is a phenomenon in which molecules dissolved or carried in a liquid (liquid or gas) attach themselves to a compound surface by which they touch. The surface of this compound is called adsorbent and the adsorbed molecule is adsorbat. We can distinguish two types of adsorption according to the nature of the interaction between the adsorbed and adsorbent molecules:

• First, physical adsorption or so-called Van der Waals: the connection formed is essentially an electrostatic type as in the Van der Waals style. In this case, the adsorption energy is weak; and

• Second, chemical adsorption: physical bonding is formed between the adsorbent and the compound by, for example, the formation of the complex on the surface of the adsorbent. Therefore, the adsorption energy is much larger, about the same magnitude as in chemical reactions. We'll just learn the first one: physical adsorption. For this, the most commonly used adsorbent is activated carbon.

Basic theory

Activated Carbons

Carbon is obtained from organic products, such as coal or wood, using a variety of methods. Activated carbon is generally obtained by high temperature processes (above 600oC). its main characteristic is its very high porosity and therefore a very large specific surface area. Since the pore size in activated carbon is very heterogeneous, it is possible to absorb molecules of different sizes.

Two forms of activated carbon are commercially available:

• Activated carbon in powder form, which is more commonly used in suspension in the medium to be treated, and then separated by filtration;

• Activated ionized car (different granulometric sizes available) used in the form of bed filtration in the adsorption column.
  The most important characteristics to consider when choosing activated carbon are:

• Specific surface area in m2 / g;

• Porosity;

• Pore volume distribution;

• Selectivity; and

• Chemical composition.

Adsorption of Heat Phases in Columns

What is phase?

Liquid phase, solvent filled with product to be adsorbed. introduced at the top of the column. Therefore in prolonged contact with the bed the activated carbon is present in the column. Flow can occur either at atmospheric pressure. or by applied pressure, depending on the viscosity of the feed mixture.

The adsorption phase

At the bottom of the column. the treated solution has recovered. It should only contain adsorbat traces that are optimal operating conditions. Adsorption remains adsorbed on

activated carbon and can be recovered during the desorption process (see desorption paragraph for more details)

Effects of properties and physical characteristics of carbon

the physical characteristics of carbon

It is advisable to select the carbon in the function to the product to be absorbed and the nature of the solvent. Even to remove color, we use a kind of carbon that is not necessarily adapted to the adsorption of other organic products for example.

However, the purpose of this experiment is not to optimize performance but to observe and understand the phenomenon. We can use "universal" active though not too selective.

For better adsorption, it is necessary to have carbon with a large specific surface area. Even. as a function of the molecular size to be absorbed, the distribution of the pore volume of carbon would be an important factor to consider.

Click Link Below

Remember to access the links below that explain about adsorption.

• Adsorption and absorption
• Understanding ABSORBSI
• DIFFERENCE OF ABSORPTION AND ADSORPTION
• Mixed Separation Method

---

Posted on Utopian.io - Rewarding Open Source Contributors

---