Absorbent Basics & Selection

We make it simple - Learn about the many types of absorbents & its applications

Absorbents, wipers and rags are used every day to clean up leaks and spills and are generally non-hazardous.

Mats, socks, pillows, loose absorbents and wipers are made from many different types of materials such as poly-propylene, cotton, corn cob and earthen minerals like vermiculite, cork and clay.

Absorbents take on the characteristics of the liquids they have absorbed, and should be handled with the same precautions as the liquid.

  • Corrosives remain corrosive
  • Flammable solvents remain flammable, etc.

Selecting the correct absorbent for the job helps keep employees & facilities safer.

Information about chemicals can be obtained from Safety Data Sheets , suppliers, chemical indexes and many online resources to properly use, store, handle, recycle and dispose of it.

What types of Sorbents Exist?

According to their constituent matter

  1. Products of mineral origin (e.g. expanded perlite, glass wool...)
  2. Products of animal or vegetable origin, possibly fossilised, (e.g. peat, cellulose, Cork...)
  3. Synthetic products and organic polymers (e.g. polypropylene, polyurethane...)

According to their selectivity

  1. Hydrophobic sorbents (also known as "oil-only sorbents") are designed to recover non-polar pollutants (i.e. non-miscible with water, e.g. oil). These sorbents are light and float. They can be deployed on water or on land. This type of sorbent can be hydrophobic by nature (e.g. polypropylene) or be treated to be hydrophobic. 
  2. Hydrophilic or "universal" sorbents are designed to recover polar products (water, substances soluble in water) and non-polar products (non-miscible with water). These sorbents soak up water and do not necessarily float (variable density). They can only be used on land (hard surface).

Criteria for selecting Sorbents

In addition to the form in which the sorbent is presented and the ability of a particular material to selectively take up oil, other factors also affect a sorbent’s effectiveness.

  1. Buoyancy - Remain afloat even when saturated with oil and water.
  2. Absorption rate - Fast Absorption rate / capillary action means quicker cleaner of spills.
  3. Saturation - Sorbents should have high saturation point / absorption capacity.
  4. Oil retention - One of the key aspects of the overall performance of a sorbent is its ability to retain Absorbed Liquids.
  5. Strength and durability - The durability of a sorbent is important in those situations where it may be left in-situ for an extended period of time before recovery.
  6. Cost - The cost of sorbent products varies greatly and is primarily dependent upon the material used. Organic and inorganic materials are comparatively less expensive than synthetic products.
  7. Availability, storage and transportation - The performance of synthetic sorbents makes their use attractive but they may not always be immediately available at the site of the spill.

How Sorbents Work?

100% polypropylene is naturally hydrophobic or repels water, while like materials adhere or are attracted to the surface area of the polypropylene fibers. And since polypropylene is a petroleum derivative, it will absorb any oil or oil-based liquids.

In addition to having a lower density than water, polypropylene's natural aversion to water made these "oil only" absorbents an excellent choice for environmental clean up. Both the oil and the absorbent floated on the top of the water.

As industrial and other indoor absorbent applications emerged, sorbents were needed to clean up more than just petroleum-based spills. Water-based liquids and chemicals leak, drip and spill in manufacturing and industrial facilities around the world. So by adding a surfactant into the manufacturing process, sorbents can absorb both oil and water-based liquids - making the product hydrophilic.

Dyes are also added in to the manufacturing process to color-code sorbents - creating a very easy to use color system to identify which absorbent you need for the job.