What are the different chemical methods used to clean up oil spills?
How do these chemical products work so as to clean up the oil spills?
There are four different types of Oil Spill Cleaning Agents, namely Dispersents, Surface Washing Agents, Bioremediation Agents and Solidifiers. All of these help in Oil Spill Cleaning in different ways.
This is just to note that crude oil does not have a clear chemical formula due to the complexity of its makeup. However, as a guide, the components of most oil are hydrogen and carbon, and the quantity of these two are determined based on the makeup of that particular oil.
Dispersents help to degrade oil into naturally occurring substances quicker. Dispersents can be applied directly to spilled oil, and help to remove oil from the water surface where it is especially harmful. It does so by first breaking the surface oil slicks. As dispersents contain molecules with both a hydrophilic and lipophilic end, these molecules attach to oil, thus reducing interfacial tensions between the water and the oil, which helps break the oil slicks. After breaking the oil slicks, it disperses oil as fine droplets into the water column through natural mixing actions such as wave action and turbulence which dilutes the subsurface oil concentration. This disperses oil from water surface to water column. Afterwhich, oil is dispersed by currents and is subjected to natural processes such as biodegradation, which will render oil harmless.
These videos shows how dispersants work:
Surface Washing Agents
Secondly, Surface Washing Agents help clean oil from substrates by emulsifying oil. These agents are mostly applicable for use with all oil types. Surface Washing Agents clean oil by two methods. Firstly, the ‘Lift and Disperse’ method, where oil is dispersed, emulsified and encapsulated. Secondly, through the ‘Lift and Float’ method where oil floats readily on water and is recoverable. After Surface Washing Agents are applied to oil spill areas, washwater from the products should be flushed into contained water bodies, recovered and properly treated. Surface Washing Agents also help separate the oil from the large volumes of water.
Thirdly, bioremediation agents make use of micro-organisms to transform hydrocarbons of oil into lighter compounds such as carbonic gas and water. This process is called mineralization, a process in which all organic carbons are transformed into mineral carbons. These bioremediation agents consist of two types which work in different ways: Fertilisers and Bacterial Consortiums. Fertilisers promote action of naturally present microflora which are probiotics which help to break down the oil into simpler substances. Bacterial Consortiums inoculates the environment to be treated, and breaks down oil spills into harmless naturally occurring substances.
Lastly, solidifiers help cleanup oil spills by changing the physical state of spilled oil from liquid to semi-solid. Solidifiers are sprayed on the shore or at the sea surface. Solidifiers form a physical bond with the oil, and the viscosity of oil increases so that the oil solidifies into a rubber-like solid which enables easy removal of oil. Solidifiers are able to form a physical bond with the oil as the solidifiers are polymers which are attracted to oil by their van der waals forces, based on the theory that molecules are attracted to other molecules with similar structures. Although solidifiers are soluble in excess solvent, continual application of solidifiers will increase the viscosity of the oil.