A high surface area superparamagnetic mesoporous spinel ferrite synthesized by a template-free approach and its adsorptive property

Magnetic mesoporous spinel NiFe2O4 of high surface area (up to 301.6 m2 g−1) and well-defined pore size distribution maximized at 2.5–16.2 nm has been synthesized by a facile oxalate decomposition process from corresponding single-phase multi-component precursor without using any pore-generating template. XRD, DSC–TG, SEM, EDS, TEM, VSM and N2 sorption isotherm techniques were employed to characterize the precursor and resulting composites. The mesoporous material showed good adsorptive property for acid orange 7 (AO7) and can be used as a magnetically separatable adsorbent to treat AO7 contained wastewater. AO7 adsorbed on the adsorbent can be facilely removed by thermal decomposition and the synthesized mesoporous NiFe2O4 can be easily recycled with maintained adsorption property.