Oil absorbent pads:  An addition to the disaster response toolkit

In Spring, 2013, in a class that explored disaster salvage techniques, one experiment involved wetting materials with water contaminated with motor oil.  Salvaging the objects from the oily environment proved to be challenging; detergents were slow but effective and required copious amounts of water.  In a search for alternative methods we found oil absorbent pads, which absorb oil while repelling water.  The pads are fabricated of polypropylene fibers.  A series of tests was run to see how the materials might be used during disaster salvage.  The experiments described below are preliminary and not quantified.

Experiment 1:  Chromatography paper in water contaminated with oil

Objective:  In the class experiment when paper was removed from oily water the result was heavily stained paper and oil spreading to other materials.  The objective here was to try to contain the oil and reduce the staining on paper.  The information reported is an amalgam of several experiments.

Vessels were filled with water and a film of motor oil was floated on the surface.  Small squares of chromatography paper were placed on top of the oil and eventually sank to the bottom of the vessel.  At that point small squares of oil absorbent pads were placed on top of the water.  As the pads became saturated they were removed and replaced with clean pads.

Removing oil from water

The oil absorbent pads worked remarkably well to attract and contain oil.  They seem to work most effectively when placed in contact with the oil layer and allowed to attract the oil rather than being manipulated across the surface.  They work slowly, but appear to remove all but a slight sheen, visible as interference colors.  The initial attempt to remove that remaining trace of oil by passing the water through a funnel fabricated of an oil absorbent pad did not work because the polypropylene repels water, so small dishes were lined with the pads and the water was placed in the depression and swirled occasionally.  After a few hours, the interference colors were no longer visible.  The water was then poured through a funnel lined with chromatography paper.  When the chromatography paper dried, it was placed under UV light, where a slight trace of oil may have been visible.  No analysis was done other than visual, nasal and tactile observations.

Removing oil from chromatography paper

The paper squares were dried by various methods, not all of which are reported here.  Drying methods included:

·      Between oil absorbent pads in a press

·      Between oil absorbent pads on the suction table

·      Between blotters in a press

·      Air dried on glass

None of the drying methods were completely satisfactory for removing oil from the chromatography paper.  Drying on an oil absorbent pad on the suction table proved about as effective as air drying the sample on a piece of glass.  Pressing paper between either the oil absorbent pads or blotters in a book press seemed to be the most effective at reducing the amount of oil in the paper.  The more pressure that was applied, the more oil seemed to be removed.  There was little observable difference between the oil absorbent pads and blotter paper, although this was not conclusive and seemed to vary with successive attempts.

Dried chromatography paper viewed under UV.  The control was washed in water; other samples are labeled.

Experiment 2:  Book in water with oil

Objective:  Removing books from oil-contaminated water in the class experiment had been extremely messy and difficult.  The objective of this experiment was to see if the oil absorbent pads might simplify the process.

A mixture of approximately 7 liters of water and 50 ml of motor oil was poured over a book in a tray and it and allowed to sit for two hours.

Oil absorbent pads were placed in the bath where they began to soak up the oil.  However, the time required to allow the pads to work was counter-productive to drying the book, so the pads were dragged across the surface of the water in the tray, removing a significant quantity of oil, and then the book was removed from the bath and placed on blotters to dry.  The oil absorbent pads were quite effective when used to wipe oil from the dust jacket and this working method did help contain the spread of the oil, as opposed to the efforts in class where oily books were dried on paper towels.

The oil absorbent pads were useful cleaning up the tray and sink and seemed more effective than paper towels and sponges.  To check this impression pieces of glass and ceramic were dipped in the oily water and then wiped clean with paper towels and with the oil absorbent pads.  The pads seemed to leave the objects with slightly less of an oil film.

Conclusion

The oil absorbent pads may be useful to have on hand for clean up after disasters.  They are very useful to remove oil floating on the surface of water.  While they may not be significantly more effective than blotter removing oil from paper, they seemed to be more efficient removing oil from harder surfaces such as the dust jacket, glass and ceramic, although some grades will leave lint.  They are less messy to work with than paper towels.  They can be squeezed out while working and the water is removed but the oil remains captured, which was useful when cleaning up.  They are made of polypropylene with no additives so health risks are minimal.  They are relatively inexpensive, especially if bought in bulk.  The pads come in different grades, some very smooth and some more fibrous.  The differences between various qualities of the pads have not been investigated.  No further investigation is planned for these pads.

Suppliers

Oil absorbent pads are readily available from industrial suppliers and easily found using the search terms "oil absorbent pads."  There are many different suppliers, some of whom will send samples.

Credits

My thanks to Rebecca Elder for finding the oil absorbent pads and helping devise the tests.