Polypropylene pads can be bought at auto supply stores and other outlets. Possible experiments could include testing which brand of pads works best and how long it takes to absorb a set quantity of oil.
Water will become less dense when frozen into ice and this gives us another technique to separate oil and water. Although this would not be practical on a large scale, you can use it on a small scale to illustrate how densities change with temperature.
Place some water and oil into a concave container, like a plastic bowl. The oil will rise to the top. Put the container in the freezer for a few hours and then take it out.
The container will now have the oil on the bottom, underneath a slab of frozen water that you should be able to remove, thus separating the two. Strangely, there are bacteria that will eat oil spills. One such bacteria that scientists have experimented with is Pseudomonas. A challenging but fascinating experiment can be carried out by mixing colonies of Pseudomonas with different types of oils and nutrients and seeing which conditions give the best bacterial growth rates.
This type of experiment should always be done with caution though since some strains of Pseudomonas can cause disease in humans. Michael Judge has been writing for over a decade and has been published in "The Globe and Mail" Canada's national newspaper and the U. Michael has worked for an aerospace firm where he was in charge of rocket propellant formulation and is now a college instructor. Water Polarity Experiments.
Why Oil Won't Mix in Water? Science Projects About Frozen Liquids. Figure 4. A Schematic of the separation setup.
B,C Separating mechanism based on the pre-wetted B filter paper or C zeolite layer. Water was dyed by methylene blue and oil was dyed by Oil Red O. Figures 4D—F and Movie S3 shows the process of separating the mixture of water and oil by using filter paper. Before separation, the filter paper was wetted with a little volume of water.
On the contrary, the oil phase always stayed above the filter paper, which was intercepted by the pre-wetted paper Figure 4F. As all of the water passed through the filter paper, the separating process stopped. The zeolite also exhibited excellent separating ability.
The separation process can repeat at last 10 cycles. Therefore, such device can achieve repeated and continuous separation. The measured separation efficiency for the filter paper was The collected oils can be recycled into use.
The mechanism of separating the mixture of water and oil was schematically illustrated in Figures 4B,C. When the filter paper or the zeolite layer is previously wetted by water, water is able to enter into and fill in the microholes of the filter paper or the gaps between the zeolite particles.
On the contrary, the underwater superoleophobicity endows the pre-wetted separating materials with the ability of repealing oil phase in the mixture, preventing the oil from passing through the filter paper or the zeolite layer. As a result, the mixture of oil and water is separated. Filter paper and zeolite particles have representative character and university.
In the aspect of source, filter paper is from our life, while zeolite particles are from nature. Regarding the morphology, filter paper is a natural porous membrane, while zeolite particles are able to stack up into zeolite layer with rich gaps. The filter paper has good flexibility and can be folded into different shapes, such as box and cylinder. The filter paper is easy to carry and can be quickly assembled into separation device. Therefore, filter paper can be used to rapidly address the complex pollutions in emergency.
The zeolite layer has good mechanical property and can be stack up into large equipment. Similar to filter paper and zeolite layer, there are a mass of existing materials in our life or in nature having both inherent porous microstructures and underwater superoleophobicity. In conclusion, we demonstrate that some existing materials e. By combining with the inherent hydrophilic chemical composition, these materials showed strong water-absorption ability as well as the superhydrophilicity in air, without any further treatment.
When the filter paper and the zeolite layer were dipped into water and an oil droplet was put on their surfaces, the oil droplet was at the underwater Cassie wetting state, resulting in the underwater superoleophobicity of these porous materials. When the mixture of water and oil was poured onto the pre-wetted filter paper or zeolite layer, only water was able to penetrate through these materials, while oil was maintained above the separating materials.
Therefore, the mixture was successfully separated with high efficiency. Such existing materials are natural, green, and low-cost materials, and can be easily obtained, showing great advantages in solving the pollution problems caused by the discharge of industrial oily wastewater and the oil-spill accidents. HB and JY designed the experiments and wrote the manuscript. FC directed and supervised the research.
QY and XH contributed toward significant discussions and revised the paper. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Movie S1. Process of an underwater oil droplet rolling on a filter paper.
Movie S2. Process of an underwater oil droplet rolling on the layer of zeolite particles. Movie S3. Process of separating the mixture of water and oil by using the pre-wetted filter paper. Movie S4. Process of separating the mixture of water and oil by using the pre-wetted zeolite layer. Movie S5. Restarting the separating process after finishing a cycle of separation. Bai, X. Superhydrophobicity-memory surfaces prepared by a femtosecond laser.
Cao, C. Robust fluorine-free superhydrophobic PDMS-ormosil fabrics for highly effective self-cleaning and efficient oil-water separation. A 4, — Cassie, A. Wettability of porous surfaces. Faraday Soc. Chu, Z. Feng, L. A super-hydrophobic and super-oleophilic coating mesh film for the separation of oil and water. Genzer, J. Recent developments in superhydrophobic surfaces and their relevance to marine fouling: a review.
Biofouling 22, — Gupta, R. Discover World-Changing Science. Materials 2 clear plastic water bottles with lids 2 cups of water One-half cup of oil olive, cooking or vegetable oils will all work Liquid dishwashing soap Clock or timer Permanent marker Measuring cup Measuring spoon Food coloring optional Preparation Remove any labels from your water bottles.
Pour one cup of water into each bottle. Allow the bottle to sit on a countertop or flat surface while you observe the water and oil. Does the oil sink to the bottom of the bottle, sit on top of the water or mix with it?
Does the oil sink to the bottom, sit on top of the water or mix with it? Try not to shake the bottle as you add the dish soap. Make sure the bottle caps are screwed on tightly to each bottle. Holding a bottle in each hand, vigorously shake the bottles for 20 seconds. Set the bottles down on a flat surface with plenty of light. Note the time on your clock or set a timer for 10 minutes. Observe the contents of each bottle. Hold them up to a light one at time so you can clearly see what is happening inside the bottle.
Did anything change when you shook the bottles? Do the mixtures look the same in the both? If not, what is different between them? How would you explain the differences that you observe?
After 10 minutes have passed look at the contents of the bottles and note the changes. What does the oil and water look like in each bottle?
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