Liquid effluent treatment using magnetite and iron ferrites

Iron ferrites and magnetite are very effective for the removal of radioactive and heavy metals from liquid effluents. The mineral magnetite, or synthetically prepared iron ferrite (FeO•Fe2O3), is typically used. Iron ferrite can be utilized for effluent treatment in a batch mode by adding preformed ferrite to the solution or by preparing the ferrite in situ, thus using the existing iron in the effluent. Natural magnetite can also be used in a batch mode or, better, in a column mode. In the presence of the external magnetic field, enhanced capacity was observed when using a column of supported magnetite for removal of actinides and heavy metals from wastewater. The enhanced capacity is thought to be primarily due to magnetic separation of colloidal and submicron particles along with some complex and ion exchange sorption mechanisms. The loaded magnetite can easily be regenerated by removing the magnetic field and using a regenerating solution. This paper will review previous work on the use of iron oxides for wastewater treatment and discuss the development and potential of the magnetic filtration/sorption process for liquid effluent treatment.

Keywords:

Iron ferrites , liquid effluent treatment , magnetite , wastewater treatment