Sunday, July 8, 2018

ADSORPTION - Adsorption is defined as the adhesion of a chemical species onto the surface of particles. Adsorption is a surface phenomenon in which particles or molecules bind to the top layer of a material. Absorption, on the other hand, goes deeper, involving the entire volume of the absorbent. Absorption is the filling of pores or holes in a substance.

Activated carbon is a common material used for adsorption.
.
Adsorption
Adsorption Definition (Chemistry)

Adsorption is defined as the adhesion of a chemical species onto the surface of particles.
German physicist Heinrich Kayser coined the term "adsorption" in 1881.
Adsorption is a different process from absorption, in which a substance diffuses into a liquid or solid to form a solution.
In adsorption, the gas or liquid particles bind to the solid or liquid surface that is termed the adsorbent. The particles form an atomic or molecular adsorbate film.
Isotherms are used to describe adsorption because temperature has a significant effect on the process.
The quantity of adsorbate bound to the adsorbent is expressed as a function of pressure of concentration at a constant temperature.
Several isotherm models have been developed to describe adsorption, including the linear, Freundlich, Langmuir, BET (after Brunauer, Emmett, and Teller), and Kisliuk theories.
IUPAC Definition of Adsorption
The IUPAC definition of adsorption is the "Increase in the concentration of a substance at the interface of a condensed and a liquid or gaseous layer owing to the operation of surface forces."
Examples of Adsorption
Examples of adsorbents include:
  • silica gel
  • alumina
  • activated carbon or charcoal
  • zeolites
  • adsorption chillers used with refrigerants
  • biomaterials that adsorb proteins
Adsorption is the first stage of a virus life cycle.
Some scientists consider the video game Tetris a model for the process of adsorption of shaped molecules onto flat surfaces.
Adsorption vs. Absorption
Adsorption is a surface phenomenon in which particles or molecules bind to the top layer of a material.
Absorption, on the other hand, goes deeper, involving the entire volume of the absorbent. Absorption is the filling of pores or holes in a substance.

Terms Related To Adsorption

Sorption: This encompasses both adsorption and absorption processes.
Desorption: The reverse process of sorption. The reverse of adsorption or absorption.
Characteristics of Adsorbents
Typically, adsorbents have small pore diameters so that there is a high surface area to facilitate adsorption. The pore size usually ranges between 0.25 and 5 mm.
Industrial adsorbents have high thermal stability and resistance to abrasion. Depending on the application, the surface may be hydrophobic or hydrophilic.
Both polar and nonpolar adsorbents exist.
The adsorbents come in many shapes, including rods, pellets, and molded shapes.
There are three major classes of industrial adsorbents:
  • carbon-based compounds (e.g., graphite, activated charcoal)
  • oxygen-based compounds (e.g., zeolites, silica)
  • polymer-base compound

How Adsorption Works

Adsorption depends on surface energy. Surface atoms of the adsorbent are partially exposed so they can attract the adsorbate molecules.
Adsorption may result from electrostatic attraction, chemisorption, or physisorption.

Uses of Adsorption

There are many applications of the adsorption process, including:
  • Adsorption is used to cool water for air conditioning units.
  • Activated charcoal is used for aquarium filtration and home water filtration.
  • Silica gel is used to prevent moisture from damaging electronics and clothing.
  • Adsorbents are used to increase the capacity of carbide-derived carbons.
  • Adsorbents are used to produce non-stick coatings on surfaces.
  • Adsorption may be used to extend the exposure time of specific drugs.
  • Zeolites are used to remove carbon dioxide from natural gas, remove carbon monoxide from reforming gas, for catalytic cracking, and other processes.
  • The process is used in chemistry labs for ion-exchange and chromatography.

 

Anne Marie Helmenstine, Ph.D. , is an author and consultant with a broad scientific and medical background.
Experience
Anne has taught chemistry, biology, and physics at the high school, college, and graduate level. In her doctoral work, Anne developed ultra-sensitive chemical detection and medical diagnostic tests. She has worked abstracting/indexing diverse scientific literature for the Department of Energy. She presently works as a freelance writer and scientific consultant. She enjoys adapting lab-based science projects so that they can be performed safely at home.
Education
Dr. Helmenstine has bachelor of arts degrees in physics and mathematics with a minor in chemistry from Hastings College in Nebraska and a doctorate of philosophy in biomedical sciences from the University of Tennessee at Knoxville.
Anne Marie Helmenstine, Ph.D.
Chemistry is part of everyone's life, from cooking and cleaning to the latest computer chip technology and vaccine development. It doesn't have to be intimidating and it doesn't have to be hard to understand.
You can read more about Anne's current and past work on her Google Profile: Anne Helmenstine. Find Anne's printable periodic tables and science projects at Science Notes.
https://www.thoughtco.com/definition-of-adsorption-605820
You might also like:

Activated Carbon 
Filtration
CLICK HERE . . . 
Activated 
Carbon 
(GAC)
CLICK HERE . . . 
.
Benefits Of Activated Charcoal
CLICK HERE . . . 
.
What Is Activated Charcoal?
CLICK HERE . . . 
.
Detox and Beautify Your Skin and Hair with Activated Charcoal 
CLICK HERE . . . 
..
Multi-Media Filter, Highly-Activated Carbon Filter,
Zeolite-Process Water Softener With Brine Tank,
Fiberglass Ballast-Type Pressure Tank
(fully automatic backwash & regeneration)
PURICARE 
INDUSTRIAL 
ENTERPRISES 
Water 
Treatment 
Systems
.
.
...
Aganan, Pavia, Iloilo, Philippines
...

CLICK HERE . . . to view company profile . . .

VENTILATION AND COOLING SYSTEMS FOR POULTRY FARMS

 

No comments:

Post a Comment