There is an urgent need of development of a sorbent for collection and separation of oily pollutant from water. It is evident that the most effective and convenient way to clean and recollect oil from oil spillage is the use of sorbents.
The technology relates to the preparation of super-oleophilic and super-hydrophobic PU sponge for separation of oil, liquid hydrocarbon, halohydrocarbon and any low surface energy liquid from water. PU sponge is modified with a low surface energy long chain hydrocarbon molecule by radiation induced covalent attachment. Modified PU sponge is super-oleophilic and super-hydrophobic in nature. The material has strong water disliking and oil liking property. This material can separate oil and oily liquid from both surface and underwater oil/water mixtures very fast, efficiently and reproducibly. It is reusable after the absorbed liquid can be recollected by centrifugation or compression. The superabsorbent can be used in harsh environment for hours, in any pH, marine environment and in boiling water.


Salient Feature

1.    By Gamma radiation or electron beam assisted process a PU sponge can be modified into a super-oleophilic and super-hydrophobic one.

2.    This special wettability is introduced on the surface as well as in the bulk of the material.

3.     This PU absorbent can absorb oil and oily substance from aqueous system at more than 30 gm/gm ratio. That is why it is called superabsorbent.

4.     It can separate oil from water surface as well as from underwater environment.

5.     Oil absorbed by superabsorbent can be removed by centrifugation or squeegeeing and the absorbent can be reused for multiple times.

6.     This superabsorbent is physically and chemically robust. Stable for hours at various pH and in boiling water.  

This material has enormous potential in dealing with many oil and oily substance (eg. toxic organic solvents etc) contamination problems, such as oil spill cleaning from water as well as from solid surface, treatment of industrial waste water, separation of organic solvents from solvent mixtures etc. 

There is an urgent need of development of a sorbent for collection and separation of oily pollutants from water. It is evident that the most effective and convenient way to clean and recollect oil from oil spillage is the use of sorbents. This technolgy relates to the preparation of super-oleophilic PU sponge for separation of oil, liquid hydrocarbon, halohydrocarbon and any low surface energy liquid from water. PU sponge is modified with a low surface energy long chain hydrocarbon molecule by radiation induced covalent attachment. Modified PU sponge is super-oleophilic and super-hydrophobic in nature. The material has strong water disliking and oil liking property. This material can separate oil from both surface and underwater oil/water mixtures very fast, efficiently and reproducibly. It is reusable after absorbed liquid can be recollected easily by centrifugation or compression.

Advantages
•    PU sponge is an inexpensive, highly porous, elastic and 3D material with a large internal surface area
•    For recycling purpose scarp PU sponge can be modified by this method
•    It can separate oil from oil/water mixture very efficiently and fast (capacity is around 30 gm/gm)
•    It can separate harmful oily substances from water medium. For haloforms (CHX3, where X is a halogen), the capacity is around 50 gm/gm, due to high density of haloforms
•    It is physically and chemically robust- can be used in harsh environment.
•    The modification technique is simple, environmental friendly and one step.
•    This material is reusable after recollection of absorbed oil and can be used several times with almost same efficiency.
•    Material being light weight and robust, has taken care logistics issues.
 
Applications
•    Separation of oil/harmful oily substances from water medium.
•    Oil/water separation for oil spillage.
•    Oil cleaning from solid surface (oil station spillage, spillage on road etc).
•    Cleaning of industrial or municipal waste water containing benzene, toluene, ethylbenzene, CHCl3, dichloro methane, tributyl phosphate (TBP), triphenyl phosphate (TPP) etc
•    Separation of mixed solvents in laboratories and industry

Process
The process of preparation is amenable for productionisation as it involves readily available PU sponge, low surface energy molecule and radiation processing unit.  PU sponge was treated with low surface energy molecules with the help of gamma or electron beam radiation in aqueous ethanol solvent only at 10 kGy or 40kGy respectively. After the treatment that was washed by an user friendly solvent followed by oven drying. This is an environment friendly easy process. Sponge adopted the selectivity towards oil and water after modification. It repels water and attracts oil or any low surface energy molecule due to its low surface energy and special surface topography.

Storage and life
The PU sponge is modified through covalently bonded attachment of a long chain hydrocarbon without introducing any structural change. Thus, the modified sponge can be stored for as long as the sponge is stable (no visual degradation observed even after 1-2 years of storage). The absorbent is stable and efficient at least up to 2 years in packed condition from the date of preparation. Even after that the PU sponge will get it properties back only by 1-2 hrs oven drying at 60° to 80°C.

Infrastructure
There is no requirement of high end infrastructure. A gamma chamber (plant for large scale production) for irradiation, a washing unit (ultrasonic bath) and some other basic instruments like weighing balance, glassware etc. are needed.

Manpower
The manpower requirement depends on the production capacity. However, for making of about 5-10 kg of such absorbent, the manpower required is 1 B.Sc and 1 person 12th pass with science background for 1 day. For continuous production similar is required accordingly