Magnetic iron oxide nanosorbents effective in dye removal

Dyes are used by different industries like leather, textile, rubber, and printing etc., to colour their products in which textile industries account for the two third of the total dye stuffs used. Industrial use of dyes creates pollutant which is toxic and causes adverse effects to living beings. Liquid waste produced by textile industries is non-biodegradable and carcinogenic. These pollutants kill soil microbes due to its toxic nature, prevent light penetration inside water and reduce the solubility of gases in water which thus is harmful to aquatic life. The best way to get rid of these toxins in the water bodies is to use magnetic iron oxide nanosorbent which possesses greater surface area that allows large number of dyes to be adsorbed on a nanosurface and could be reused by utilising its magnetic nature which makes it economical than other nanosorbents. The iron oxide nanoparticles also have the tendency to adsorb dyes, but it adsorbs dyes more, with hydroxyl (OH) groups on their surface such as erichrome black-T, bromophenol blue, bromocresol green, and fluorescein than other dyes such as methyl red, methylene blue, and methyl orange. Modified iron oxide nanoparticles provide charge-specific cationic or anionic dye removal, like the coating of SDS on the surface of iron oxide nanoparticles could remove cationic dye. It has become an effective method for dye removal in comparison to the previous conventional methods. In this review, detailed study of dye removal has been presented using iron oxide nanoparticles and their modifications.