Improvement of Adsorbing Properties of Magnetic Nanomaterials by Bioorganic Substrate-mediating Synthesis

Abstract

Pure water for analytical use must be free of heavy metals and others contaminants.On-site analysis requires portable water purification devices toimprove the quality of water for analytical purposes. Simple water purifiersmade of nanoscale magnetic nanoparticles combine the surface usefulproperties possessed by the nanoscale materials with the possibility of aneasy separation from the aqueous media by an external magnetic field afterthe treatment. The present chapter focuses on the preparation of magneticnanoparticles with different coatings in order to evaluate their sorptioncapacity toward metal ions and dyes. In particular, bioorganic substrateswere used to coat and template the nanoparticles combining new availablesurface groups which are involved in the adsorption mechanism. The advantagesof the use of soluble bioorganic materials are their low cost, and thestrategy of recycle and reuse of waste products. Also, 15 nm size magnetitenanoparticles composed of a crystalline magnetite core and coated withYerba Mate (Ilex paraguariensis) extract, which preferentially incorporatessurface carboxylates, phenols, and some organic N groups, is capable ofreversibly adsorbing the cationic colorant methylene blue from water.Paramagnetic iron-containing hydroxyapatite (Fe-nAp) nanoparticles andwaste bioorganic substrates template iron-containing hydroxyapatite (SBO?Fe-nAp) nanoparticles show particular selectivity in adsorption experimentsinvolving Cu(II) and Pb(II) ions from water depending on the surface chemistryof the hydroxyapatite-based adsorbent.