Fulvic acid decorated Fe3O4 magnetic nanocomposites for the highly efficient sequestration of Ni(II) from an aqueous solution

Recently, magnetic nano-materials have attracted great attention as effective and potential adsorbents for the fast sequestration and quick separation of contaminants in the real work of wastewater treatment. In the present work, fulvic acid (FA) decorated Fe3O4 (Fe3O4/FA) magnetic nanocomposites were developed for the sequestration of Ni(II) by an adsorption process from a synthetic wastewater. The results indicated that the surface-coated FA improves the dispersion of Fe3O4/FA and promotes the removal performance of Fe3O4/FA towards Ni(II). The retention of Ni(II) onto Fe3O4/FA obtained adsorption equilibrium in less than 2 h, and could be well described by the Langmuir adsorption model. The adsorption of Ni(II) onto Fe3O4/FA was strongly pH-dependent and ionic strength-independent, and so the inner-sphere surface complexation is the main mechanism responsible for the uptake of Ni(II) onto Fe3O4/FA. The Fe3O4/FA magnetic composites were able to remove similar to 95.0% of Ni(II) from an aqueous solution at optimized pH. The Fe3O4/FA also showed good regeneration and separation convenience for the treatment of simulated Ni(II)-bearing effluent. Considering the low-priced and environmental friendly properties, we can see that FA could be easily coated on magnetic nanocomposites to form novel nanocomposites by a simple co-precipitation procedure for the development of a new environmental remediation method and to find the application potential of these magnetic nanocomposites in environmental fields. (C) 2015 Elsevier B.V. All rights reserved.