Not all molecular sieves are created equal, and you want to be sure to get the one that is right for your needs. Read on to find out more about what a sieve does and what the various sizes offer!

What is a Molecular Sieve?
A molecular sieve, also called a mole sieve, is a type of drying agent that can absorb certain, specific materials. It is made of a porous, crystalline material. The pores, measured in angstroms, are a uniform size similar in size to small molecules. That means larger molecules cannot enter through the material or be absorbed but the smaller ones can.  Molecular sieve desiccants act as drying agents and are very successful at removing water from other liquids and gases.

Molecular Sieve vs. Silica Gel
While molecular sieves are similar in nature to silica gel, they are actually more effective due to their crystalline composition. In fact, molecular sieves can keep products almost entirely water-free.

Molecular Sieve Products
There are various mole sieve products on the market to fit your needs. Check out molecular sieve 3A, molecular sieve 4A, and the molecular sieve 5A:

Molecular Sieve 3A
Molecular sieve 3A offers a pore size of 3 angstroms, which means that any molecule larger than 3A will not be absorbed. The 3 Angstrom sieve is created when potassium ions replace a portion of the sodium ions of the 4 Angstrom sieve. The sequence rate of this sieve is helium, neon, nitrogen and water.

The molecular sieve 3A has many advantages. It has a consistently high absorption speed, strong crushing strength, and high contamination resistance, which increase cyclic times, thereby extending product life. For these reasons, it has become one of the most reliable desiccants and is often used for the following applications:

• Refrigerant Drying
• Natural Gas Drying
• Moisture removal in paint or PU Plastic
• Drying Cracked Gas
• Static drying of insulating air or gas-filled glass units
• Dehydration of highly polar compounds, such as methanol and ethanol
• Dehydration of unsaturated hydrocarbons (such as ethylene, propylene, butadiene)

Molecular sieve 3A can also be regenerated and reused by removing the absorbed moisture and other materials, and then heating it to 250 degrees Fahrenheit. Then store the sieve in an airtight container until ready to use again to avoid any unintentional moisture absorption.

Molecular Sieve 4A
Molecular sieve 4A offers an angstrom size of 4, so any molecule greater than 4A cannot be absorbed. 4 angstroms are the sodium forms of the crystal structure known as Type A, with a sequence rate of absorption as follows: argon, krypton, xenon, ammonia, carbon monoxide, C2H4, C2H2, CH3OH, C2H5OH, CH3CN2, CS2, CH3CL, CH3Br, and carbon dioxide.

Like the 3A, the 4A mole sieve has a consistently high absorption speed, strong crushing strength, and high contamination resistance, contributing to extended product life. It is primarily used for removing moisture from liquefied and gaseous materials. The 4A absorbent is also used for the following applications:

• Refrigerant Drying
• Natural Gas Drying
• Moisture removal in paint or PU Plastic
• Drying Cracked Gas
• Static drying of insulating air or gas-filled glass units
• Dehydration of highly polar compounds, such as methanol and ethanol
• Dehydration of unsaturated hydrocarbons (such as ethylene, propylene, butadiene)

Like the 3A sieve, the 4A type can also be reused and regenerated. First, you will want to remove the absorbed moisture and other materials, and then heat it to 250 to 450 degrees Fahrenheit. Then store the sieve in an airtight container until ready to use again to avoid any unintentional moisture absorption.

Molecular Sieve 5A
Molecular sieve 5A has a pore size of 5 angstroms, meaning it cannot absorb molecules smaller than 5A. This type is an alkali aluminosilicate in the claim form of Type A crystal structure. That means it will separate normal and isomerous alkane, the co-absorption of moisture and carbon dioxide, as well as pressure swing absorption (PSA) for various gases. The 5A sieve sequence rate of adsorption is as follows: C3-C14, C2H5CL, C2H5Br, CH3L, C2H5NH2, CH2CL2CH2Br2, CHF2CL, CHF3, CF4, (CH3)NH2, B2H6CF2CL2, CHFCL2, and CF3CL.

The type 5A sieve is a dependable desiccant for the following applications:

• Normal paraffin separating process
• Oxygen/hydrogen PSA (Pressure Swing Adsorption) process
• Refining SF6 refrigerant for power (removing moisture and hydrocarbon)

Time to Get Your Absorbents

When it’s time to purchase your molecular sieves, contact us at Delta Adsorbents. Our knowledgeable staff can help you with all your questions and needs today!