The use of magnetic polymers in water treatment

Abstract

Abstract Magnetic polymers, originally conceived in ion‐exchange form as a means of handling microbeads in a thermally regenerable desalination process, have now been prepared in a variety of configurations for use in a number of water purification procedures. Processes have been devised which employ magnetic polymers in filtration, in oil slick removal, and in the adsorption of metal ions. Suitably shaped particles, when magnetized, form a filter bed of high voidage volume. Tests have been run on a variety of turbid waters. The particles give considerably better performance as filter aids than the diatomaceous earth normally used. An extremely important advantage is that the magnetic filter aids can be recovered and reused after washing. Vesicular forms of magnetic hydrophobic polymers float on water and have application in the removal of oil spills from water surfaces. The oil becomes trapped in the voids between the particles; the resulting mass is readily removed from the water by magnetic means, after which the oil is separated from the particles simply by centrifugation. The particles and residual oil are then recycled. Magnetic ion exchangers, smaller in size than conventional resins, can be employed in continuous contacting systems, such as fluidized and semifluidized beds. When compared with normal continuous ion‐exchange systems, the same removal of ions can be accomplished using considerably less resin in a plant which is smaller, simpler, and much cheaper to construct.