The invention relates to the preparation of multifunctional superabsorbent cotton for separation of oil, hydrocarbon based solvent, halohydrocarbon and any low surface energy liquid from water. Cotton is modified with a reagent using controlled radiation induced grafting. Developed cotton is super-hydrophobic and super-oleophilic in nature. This material can separate oil and water from both immiscible as well as emulsified mixtures very fast, efficiently and reproducibly. The material has strong water disliking and oil liking property. It is reusable and absorbed liquid can be recollected easily.
The invention relates to the preparation of multifunctional superabsorbent cotton for separation of oil, hydrocarbon based solvent, halohydrocarbon and any low surface energy liquid from water. Cotton is modified with a reagent using controlled radiation induced grafting. Developed cotton is super-hydrophobic and super-oleophilic in nature. This material can separate oil and water from both immiscible as well as emulsified mixtures very fast, efficiently and reproducibly. The material has strong water disliking and oil liking property. It is reusable and absorbed liquid can be recollected easily.
Except the above uses the material can be used as super-hydrophobic material for following cases
In the last few years oil spillage has become one of the most serious environmental and ecological issues. There is an urgent need of development of material for collection and separation of oily pollutant from water surfaces. The most effective and convenient way to clean and recollect oil from oil spillage is the use of sorbents.
A cotton based super-hydrophobic and super-oleophilic material has been developed. This is highly efficient oil/water separator. The process involves radiation assisted grafting of long chain acrylate, which is environmental friendly, inexpensive and highly scalable process. Superabsorbent can be used in acidic, basic, saline and underwater condition with efficacy. 1gm cotton takes 5 seconds to absorb 30gm of oil for layered oil water mixture and 8-9 min to remove oil from emulsified oil/water mixtures. The absorbed oil can be completely recollected by centrifuging the absorbent at 600-1000 rpm for 1 minute and the same piece of absorbent can be repetitively used for more than 50 times for the same purpose without compromising its mechanical & special wetting properties. This recollection can be performed by squeezing the absorbent. Selectivity and capacity of the cotton has been studied by varying different kinds of oils/oily liquids namely, motor oil, diesel, edible oil (mustard oil), petrol, high speed diesel (HSD), crude oil, toluene, chloroform, dichloromethane etc.
Except the above uses the material can be used as super-hydrophobic material for following cases
PROCESS
Gauze cotton was grafted with low surface energy molecules by gamma radiation in aqueous ethanol solvent only at 10 kGy. After grafting that was washed by ethyl acetate followed by oven drying. This is an environment friendly easy process. Cotton adopted the selectivity towards oil and water after grafting. It repels water and attracts oil or any low surface energy molecule due to its low surface energy and special surface topography.
WASTE DISPOSAL PROCEDURE
The base material cotton is naturally biodegradable. The absorbent contain 80-85% of cotton and 15-20% of grafted material (long chain hydrocarbon). So, the 80-85% of the absorbent is completely biodegradable under atmospheric or in landfill condition. 15-20% of long chain hydrocarbon can be recycled. It is not harmful or toxic material. It is just like other polyolefins, LDPE, HDPE etc. Thus, after multiple use this can be easily disposed.
HANDLING
The base substrate cotton is natural, non-toxic, biodegradable hence it doesn’t need any special handling process. The associated chemicals need to be handled as per materials safety data sheet (MSDS). Our other used chemicals are very user and environmental friendly. All chemicals can be handled just by reasonable lab safety awareness.
PACKAGING
Design flexibility is an advantage of the material. The absorbent can be prepared of any size, shape as per the requirement. For long term and efficient performance the material is recommended to store in any air tight packet (plastic zip lock bag ) and away from high moisture and UV area.
STORAGE AND LIFE
The cotton is modified through covalently bonded attachment of a long chain hydrocarbon without introducing any structural change. Thus, the modified cotton can be stored for as long as the cotton is stable. Stability of cotton in atmosphere is 1-5 years. The absorbent is stable and efficient at least up to 2 years in packed condition from the date of preparation. Even after that the cotton will gets it properties back only by 1-2 hrs oven drying.
HAZARDS INVOLVED
The process of preparation of the material is environment friendly. Irradiation takes place at room temperature. It involves very few chemicals and steps. As a solvent ethanol and water have been used, which are very common regularly used solvent. Washing solvent, ethyl acetate is inflammable and should be handled as per material safety data sheet.
BATCH TESTING
Batch testing of the samples prepared by this method can be easily performed by water drop beading on the surface and by oil absorption from surface (floating oil) as well as from underwater environment ( sediment). Spherical water droplet on the modified cotton surface confirms proper modification (super-hydrophobicity). Oil absorption from surface and underwater can be investigated by using mixture of oil and water in a beaker. Selective absorption of oil from aqueous media confirms the successful completion of the process.
INFRASTRUCTURE
A gamma chamber for irradiation (Optional), a washing unit (ultrasonic bath) and some other basic instrument like weighing balance, glassware etc. are needed.
MANPOWER
The manpower requirements depend on the production capacity. However, for making of about 10 kg of such absorbent, the manpower required is 1 person with B.Sc and 1 person 12th pass with science background.
