Scientists have developed a simple, cheap and environment-friendly system that can effectively remove crude oil from the sea that can pollute and even destroy marine ecosystems. The hydrophobic sorbent developed by scientists can suck up oil and congeal it.
Scientists developed the hydrophobic sorbent by using a cheap raw material (mannitol) and cellulose pulp as a matrix. (A hydrophobic material automatically becomes oil-loving and takes up oil when it comes in contact with it). Mannitol was converted into a hydrophobic gelator through a one-step process and a solution was made using this compound. Cellulose balls the size of marbles were then dipped in the solution and dried.
The gelator gets adsorbed on the cellulose fibre through hydrogen bonding. This process of adsorption of gelator on the cellulose fibre matrix changes the cellulose matrix from being very hydrophilic (water-loving) to hydrophobic (water repelling).
A hydrophobic material naturally becomes oleophilic (oil-loving).
Unlike other alternatives, the sorbent can be easily applied over oil-water mixture, and no solvent is needed for spraying the gelator thus making it environmentally benign. The gelator adsorbed on the surface of cellulose fibre is able to absorb oil when it comes in contact with it.
Once the sorbent sucks the oil, the gelator slowly gets released from the cellulose fibre and congealing of oil takes place. Only when the oil congeals can it be removed without the oil dripping due to gravity.
Congealing of oil becomes possible as the gelator used by scientists self-assembles to form micro fibres and the oil loses its fluidity and gets trapped within the entangled fibrous network to form a rigid gel. Gelation essentially turns the liquid oil phase into a semi-solid one and this allows the fibre balls with the congealed oil to be simply scooped out or removed using a scoop or a sieve.
It takes only about 30 minutes to two hours from the time of application to scooping out the rigid fibre balls containing congealed oil, leaving behind clean water. Studies found that the sorbent was able to absorb and congeal 16 times its own weight of oil. The absorbed oil can be recovered by applying pressure or fractionated by a simple distillation process.