|Title||Synthesis of Magnetic Materials from Natural Carbon Precursors ‒ a Review|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||ZUBRIK, Anton, LOVÁS Michal, MATIK Marek, ŠTEFUŠOVÁ Katarína, and HREDZÁK Slavomír|
|Journal||Journal of the Polish Mineral Engineering Society|
Preparation methods, properties and utilization of magnetic materials based on natural carbon precursors are summarized in this short review. Magnetic material is defined as the composite material consist of carbon substance coming from natural precursor such as coal/biomass and magnetic substance. Various processes can be applied to prepare magnetic materials. Pyrolysis of the biomass/coal together with iron ions and coprecipitation of Fe2+/Fe3+ with charcoal are mostly used methods for synthesis of magnetic biochar. The pyrolysis is defined as a thermal degradation in the absence of oxygen, which converts a raw material into different reactive intermediate products: solid (char), liquid and gaseous products. Especially, microwave pyrolysis of natural materials with iron ions is one of the best techniques offering homogenous, rapid and energetically efficient heating system to produce magnetic material. After the synthesis, iron particles are incorporated to the pore carbon structure and can form (especially in thermal process) microparticles as well as nanosized particles with defined structure possessing magnetic properties, high pore volume and high specific surface area. Magnetic carbon is used mainly as an excellent sorbent material mainly for organic pollutants and heavy metals. Moreover, solid/liquid magnetic separation as a rapid and effective technique can be applied in removal of used magnetic biochar from aqueous solution after sorption process. After sorption and pre-concentration, the magnetic sorbent can be effectively regenerated e.g. by high temperature (organic pollutants such as azodyes, pesticides) and leaching methods (inorganic contaminates).