Solvo-thermal synthesis, characterization of aluminon-functionalized magnetic nanoparticles and investigation of its adsorption performance for Cr(VI) and Cr(III)

•Solvo-thermal preparation of aluminon functionalized magnetite nanoparticles (Fe3O4@aluminon MNPs) by a simple one-pot method.•Fe3O4@aluminon MNPs were used for the removal of Cr(VI) and Cr(III) from aqueous solutions.•The sorption equilibria were established within 20 min and well described by the Langmuir model.•Fe3O4@aluminon showed excellent efficiency for Cr(VI) and Cr(III) extraction from real contaminated wastewater samples.

The aluminon functionalized MNPs (Fe3O4@aluminon) as a novel magnetic nano-sorbent have been synthesized by a simple hydro-thermal method for the removal of Cr(VI) and Cr(III) from aqueous solution. Fe3O4@aluminon MNPs were characterized using SEM, HRTEM, FTIR, VSM and TGA techniques. The Fe3O4@aluminon nano-sorbent has good dispersibility and valuable magnetic property. The effects of pH, equilibration time, mass of nano-sorbent and initial concentration of adsorbate on the percentage recovery of Cr(VI) and Cr(III) by Fe3O4@aluminon were investigated. The adsorption equilibrium was attained in 20 min at 25 °C and the adsorption kinetics obeyed the pseudo-second order model. The experimental data for the adsorption of Cr(VI) and Cr(III) better fitted the Langmuir isotherm and the maximum adsorption capacities were 263.2 mg/g for Cr(VI) at pH 1.0 and 400.0 mg/g for Cr(III) at pH 7.0. The adsorption–desorption cycles revealed that Fe3O4@aluminon nanoparticles had high stability and appropriate reusability. The removal efficiencies of chromium ions from different water samples were successfully accomplished (∼ 95.0–96.7 ± 1.4–2.1%).

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