What Are Sorbents & How Do They Work?

What Are Sorbents and How Do They Work?

Workplace spills and leaks can have big consequences for both workers and the environment. Hydrocarbon fuels such as diesel, propane and gasoline are commonly found in many facilities. When exposed to air, the vapors can irritate the eyes and damage the lungs if inhaled. Fluids such as coolant and oils can make floors slick and slippery, while seepage can contaminate the surrounding soil and cost thousands of dollars in fines.

Spills and leaks can be unpredictable and understanding what sorbent options are available and how to use them can make all the difference in whether a spill or leak is held to a minimal impact or becomes a major problem.   This guide will help you better understand sorbent terminology, what a sorbent is, differences in types of sorbents and how to choose the right sorbents for your needs.

Not All Spills Are Alike

In most facilities, the there is a high potential for some type of spill.  It’s not a matter of if but rather of what, where, when and how. Identifying the types of fluids stored in your facility will help you determine the best products to use. Most spills fall into one of three categories:

Universal Spills:  Spills that consist of water-based chemicals and solvents. These non-aggressive spills are the most common, and spill control products rated as “Universal” work best.

Oil/Petroleum Spills:  Spills that consist of hydrophobic hydrocarbons (such as diesel, gasoline and butane). They tend to cluster while repelling water.  Oil Only sorbent products are designed to repel water while adsorbing the oil.

Chemical Spills:  Spills consisting of aggressive substances such as acids and bases. They require special synthetic sorbents found in chemical spill kits that are capable of withstanding corrosion.

What is Adsorbent and Absorbent: Do You Know the Difference?

Sorbents are designed to either absorb or adsorb.  Although these words sound similar, there’s a big difference in their meanings.  When it comes to these two processes, here’s what you need to know:

What is Absorption?

When a liquid is absorbed, it is “grabbed” into the media.  In order for that to happen, the liquid molecules must be small enough to dissolve into the material.   This is why a universal sorbent does not absorb oil based material - the oil molecules are too big and the universal sorbent material (i.e. cellulose) is too dense.

What is Adsorption?

When a liquid is adsorbed, it sticks to the surface of the media. This means that oil only sorbents need to have more surface area. Polypropylene works well for this because the fibers help attract oils to their surface.

Types of Sorbents:

Spill type, spill size (or volume) and spill location all determine what kind of sorbents to use in order to control, contain and clean a spill. Here are the most common sorbents and their applications:

Pads, Rolls and Mats

Absorbent Pads and Rolls are designed for extended use and can be durable enough to accommodate foot and equipment traffic. They are ideal for areas that commonly experience incidental spills or leaks such as aisles, walkways or below and around equipment.

Absorbent mats feature non-slip surfaces and are even available in patterned prints to hide stains. Rolls come in perforated sheets that can be cut to size allowing you to only use as much as you need.

Absorbent Pillows

Absorbent Pillows contain media that allows them to soak up large amounts of fluid. They are flexible and easy to fit into tight corners and spaces or placed on top of a spill that has already been contained with a sock or boom. Depending on the type of spill the pillow is designed for, it may contain cellulose for universal spills or polypropylene for oils, acids and bases.

Absorbent Socks

Socks are one of the most versatile absorbent products you can have available for spill containment and control.  Their length allows them to be placed around leaking equipment and tanks, or they can be used as a barrier to protect drain grates and contain spills of just about any size.  Socks can also be molded to fit into corners and work well on uneven surfaces.

Spill Kits

Spill Kits are self-contained kits which include all of the necessary absorbent materials necessary to clean up a spill up to a specific size.  For instance, a 5 gallon spill kit would be capable of cleaning up a spill with a volume of up to 5 gallons of fluid.  Spill kits are required in many facilities and are always a good thing to keep on hand in the event of an unforeseen spill.  

What are loose sorbents?

Loose Sorbents can be made out of organic or synthetic materials. These work well for small cracks and crevices, soil, or as the final step in your clean-up procedure to remove the oil sheen from floors and other surfaces.

What to Look for When Selecting a Sorbent

Whether you work with cooking oil or corrosive chemicals, determining your sorbent needs comes down to more than just the types of fluids stored in your facility. You'll also want to consider capacity, application, storage and disposal.  Below we outline each of these variables:

Capacity:  When a sorbent becomes saturated, it loses its ability to continue soaking up fluid. Over-saturated sorbents can release their contents when lifted, causing possible secondary contamination. Requirements for calculating sorbent capacity vary by city, state and whether your facility must comply with the SPCC rule.

Application:  Sorbents are available for many types of applications. Some are designed to float on top of water or cover a large surface area for big spills.  Others might consist of loose materials and require a fan or blower for application.

Storage:  How your spill control products are stored may determine their effectiveness over time. For instance, many oil-only sorbents have a UV coating that deteriorates when exposed to sunlight, making them less effective when they are needed. Most spill control kits come packed in their own storage container, which can be a good solution if you don't already have a cool, dark, dry place to store your sorbents.

Disposal:   Whether a sorbent is suitable for many uses or one-time use, you will eventually need to dispose of it. How you dispose of used sorbents depends on the type of liquid it contains. Some sorbents can be incinerated, while others may require hazardous waste removal.  Sorbent disposal varies on state and local levels, so it is best to check local, state and federal regulations regarding the disposal of used sorbents before you ever have to use them.

Along with properly trained employees, having the right sorbents on hand can help you increase the effectiveness of your spill control plan.

Source: US EPA

The information contained in this article is for information, educational and promotional purposes only and is based on the information available as of the initial date of publication.  It is the reader’s responsibility to ensure compliance with all applicable laws, rules, codes and regulations.  If there is any question or doubt in regards to any element contained in this article, please consult a licensed professional.  Under no circumstances will SupplyLand be liable for any loss or damage caused by your reliance on this article.