Magnetic foams

AMT&C Ltd conducts researches and developments in the field of liquid and solid foams containing magnetic submicron and nanosize particles. Such foams reveal magnetic properties and can be used for collection of oil or other hydrophobic pollution from water or solid surface. Solid magnetic foams also can be used for absorption and shielding of electromagnetic radiofrequency radiation. 
Liquid foam with residual magnetization can be used as highly effective material for collection hydrophobic pollutions (oil and other spills, etc.) from the surface of water or solid body because it is attracted by magnets. Such foam should contain magnetic nanoparticles with hard magnetic properties. Liquid foams themselves have good ability to absorb oil or other hydrophobic products. Besides, liquid foams can be easily destructed in order to extract absorbed products. The problem is in collection of the foam containing absorbed pollution. There are many different methods of hydrophobic pollution collection from water or solid body surface. Among them mechanical, biological, physical and chemical methods can be mentioned. The general drawback of the listed methods – their low productivity. In particular, mechanical methods do not allow collecting thin films on the water surface and are useful only for collection of big oil spills. Such method as burning is rather dangerous and produces combustion products harmful for nature. Biological methods require much time and elevated temperatures. 
Using of the magnetic liquid foam can essentially increase effectiveness of hydrophobic pollution collection from water or solid body surface. Besides application of the magnetic foam is effective for collection of thin oil films from water surface. Liquid magnetic foam is hydrophobic and can be stable on water surface for tenths of minutes. At the same time the process of pollution absorption takes several minutes. Rapid absorption of the pollution by the foam allows to begin the process of the foam collection practically immediately with the help of magnetic pick-up devices. High speed of the foam generation makes it possible to cover the removing spill repeatedly. Such repeated treatment of the oil pollution can essentially increase the effectiveness of its removing. The foam can be produced in large quantities on the place of pollution (i.e. on the ships or seaports), which is especially important because in accordance with international agreements seaports should have special equipment for removing the oil pollutions. Solid foam sorbents with magnetic properties also increases the cleaning process effectiveness because they essentially simplify the collection stage. The mentioned potential advantages of the magnetic foams using for oil pollution removing make development of the method of its production very actual task. 
Solid magnetic foam for absorption of radio waves can be prepared on the basis of soft magnetic ferrites, which possess good absorption properties for radiofrequency radiation. Presence of cavities of various diameters in the foam (and consequently absorption units consisting of magnetic nanoparticles) makes it possible to provide the absorption properties in wide range of frequencies. The magnetic and absorption properties of the foam can be regulated in wide range by choosing of the particles material and dimensions. It is also possible to create multilayered covering using solid magnetic foams with different magnetic properties in order to provide change of magnetic and dielectric permeability on the cover thickness necessary to obtain maximum absorption effect. The magnetic solid foam can be easy, fast and cheaply deposited on the surfaces even with complex form by well-known and developed methods.