Raw cotton and ginning byproducts are ideal materials for oil clean-up in the Gulf of Mexico.
The Deepwater Horizon oil spill has been deemed the greatest environmental disaster in U.S. history. Because the Gulf of Mexico arcs across the southern-most borders of the U.S. cotton belt, the spill is of particular concern to the cotton industry. There has been much press and speculation on what role cotton and cotton ginning byproducts (CGB) could play in the Gulf clean-up efforts. This document is an attempt to put the viability of cotton into context. Drawing on peer-reviewed scientific studies and interviews with experts from the nonwovens industry, this overview will address the opportunities and challenges of using cotton in for oil clean-up in the Gulf of Mexico.
Cotton Absorbs Oil
It is important to state at the outset that only raw cotton and raw cotton ginning byproducts (CGB) are viable for both oil absorption and floatation.
Raw cotton and CGB are naturally oleophilic (oil-absorbing). In a study by the Laboratoire de Chimie Agro-Industrielle from 2003, researchers concluded that raw cotton fiber can absorb as much as 21 grams of petroleum per gram of fiber.
A 1994 paper published in the journal Applied Engineering in Agriculture concluded that CGB could absorb as much as 80-times their own weight in oil (Absorption of Oil with Cotton Products and Kenaf, W.S. Anthony; Applied Engineering in Agriculture, vol. 10(3):357-361). The Anthony study used SAE 30 weight oil.
Today, manufacturers of commercially-available cotton-based sorbent booms and wipes conclude that, in real-world trials using crude oil, raw cotton absorbs roughly twice as much by weight as polypropylene (petroleum-based) wipes and booms that are more generally used in the United States.
Cotton Also Floats
The hydrophobic and oleophilic nature of cotton and CGB make them viable choices for water-surface oil clean-up. These natural traits allow raw cotton products to absorb high volumes of oil, while remaining afloat for retrieval.
Cotton is an Ideal Sorbent
The hydrophobic and oleophilic nature of cotton and CGB make them viable choices for water-surface oil clean-up. These natural traits allow raw cotton products to absorb high volumes of oil, while remaining afloat for retrieval.
Three Stages of Clean-up
There are three basic stages to addressing an oil spill such as the one in the Gulf of Mexico: 1) containment; during which non-absorbent booms are used to halt or ‘contain’ the oil slick on the water’s surface (containment booms); 2) water-surface absorption; during which absorbent booms are deployed to absorb the oil on the surface, retrieved and then replaced or reused (absorption booms); and 3) coastal surface absorption, during which large absorbent sheets /pads or ‘wipes’ are laid down along the coastline to absorb oil that has made landfall. Cotton-containing products are most viable for the second and third stages of clean-up; although in some cases absorbent booms are being used both to contain and absorb.
Challenges
The primary challenges facing the use of cotton-containing booms and wipes for the Gulf clean-up efforts fall into the categories of: manufacturing, product education, the approval process, distribution, and the use of the Corexit Chemical Dispersant.
Manufacturing
Most cotton and CGB are manufactured into products only after they have been processed in some way that removes the natural waxes and pectins. Simply put, those coatings can gum up a machine. While there are numerous cotton-containing sorbent products for land-based spills, they are often made from processed cotton. To retain the oleophilic and hydrophobic properties needed for water-based oil spills, the cotton or CGB must be raw.
Two companies currently offering such products are Sellars Company and Hobbs Bonded Fibers.
Sellars Company realized the potential of raw CGB for oil clean-up a few years ago and, upon finding no existing machinery that could run raw cotton, designed and built their own. The Milwaukee-based company introduced its Oil Only EverSoak® brand of wipes, pads and rolls --- all with the patent-pending Q-CEL technology --- in 2009. Sellars’ product range and production capabilities offer variety and a steady supply to local clean-up crews.
Another product comes from Hobbs Bonded Fibers, which manufactures the patented Fibertect® sorbent created by Seshadri Ramkumar at The Institute of Environmental and Human Health at Texas Tech University (US Patent: 7,516,525 April 14, 2009). The Fibertect® sorbent is a wipe; essentially a layer of activated carbon sandwiched between a top and bottom layer of raw cotton composite, and needlepunched into a sheet. This product was created as a decontamination wipe for the U.S. military and first-responders, but its engineering makes it ideal for oil clean-up, as well. While the exteriors leverage the absorption capabilities of raw cotton, the carbon layer neutralizes potentially harmful volatile gases associated with the spill. Fibertect® is distributed by First Line Technology, Chantilly, VA.
Product Education
In a rush to use any and all products for water-based clean-up, some booms containing processed cotton have been used; these products promptly sank. Some education on the distinction between raw and processed cotton and CGB products may be necessary to get local vendor buy-in. Interestingly, oil-spill clean-up crews in Scandinavian countries will use only cotton-based booms and wipes.
Approval Process
Currently, there exists no precise process of getting a product approved for use in the clean-up efforts. An endorsement from the Environmental Protection Agency and the U.S. Coast Guard can be influential. British Petroleum (BP), to some degree, is still part of the process. However, it is estimated that there are well over 31,000 vendors with products or services awaiting approval from BP.
Distribution
The scale of the spill in the Gulf has created a demand for clean-up related products and services. Ensuring the timely delivery of a ready supply could prove difficult for some manufacturers. Many companies, like Sellars, have leased warehouse space in the region and have marshaled a system of replenishment to ensure product availability.
Corexit Chemical Dispersant
Another potential challenge is the ongoing use of the Corexit chemical dispersant. BP has released close to one million gallons of the dispersant into the ocean to dissipate the crude oil. The composition of Corexit reportedly includes surfactants which could degrade the natural waxes of raw cotton and neutralize the buoyancy of cotton-containing booms. It should be noted that industry experts conjecture that booms of any source material, including polypropylene, could become ineffective and sink with prolonged contact to the dispersant.
Conclusion
The natural oleophilic and hydrophobic properties of raw cotton fiber and CGB make them viable and, in some aspects, superior source materials for oil-spill clean-up. Ginners looking to provide source material should reach out to appropriate nonwovens manufacturers. In turn, manufacturers of raw cotton fiber and CGB products would be well advised to coordinate their production and distribution processes, and to liaise with local clean-up crews in the Gulf, as well as with the Environmental Protection Agency, the U.S. Coast Guard and British Petroleum. While challenges exists, the fact that cotton and CGB are natural, readily-available, and offer superior absorptive capability, positions them as uniquely ideal materials to assist in the Gulf clean-up.
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