Synthesis and Characterization of Humic Acid-coated Fe3O4 Nanoparticles for Methylene Blue Adsorption Activity

Geitu Yirga, H C Ananda Murthy and Eshetu Bekele*

Adv. Mater. Lett., 2019, 10 (10), pp 715-723

DOI: 10.5185/amlett.2019.0049

Publication Date (Web): Sep 18, 2019

Copyright © IAAM-VBRI Press

E-mail: eshetubekele@gmail.com

Abstract

Humic acid modified magnetite nanoparticles (HA-Fe₃O₄ NPs) were synthesized by co-precipitation method by varying the precursor magnetite to HA ratio of 10:1 and 20:1. The synthesized NPs were characterized by FTIR, XRD, SEM-EDX and UV-Vis DR Techniques. The appearance of C=O vibration at 1390 cm^-1 confirms positive interaction of carboxylate anion of HA and Fe₃O₄. The XRD pattern and SEM image shows bare Fe₃O₄ and HA-Fe₃O₄ (10:1 and 20:1) exhibit cubic spinel structure and the spherical shape morphology, respectively. The crystallite sizes of NPs were found to be 11.50 nm, 9.17 nm and 12.65 nm for bare, 10:1 and 20:1 Fe₃O₄-NPs, respectively. The adsorption capacity for the dye was found to increase with increase in contact time, adsorbent dose and initial pH of the solution. The result was best fitted to pseudo 2^nd order kinetics model and Langmuir isotherm model. The methylene blue (MB) removal efficiency of bare_, 10:1 and 20:1 Fe₃O₄-NPs from aqueous solutions was recorded to be 95.8%, 99.4%, and 97.6%, respectively. The study confirms the greater efficiency of HA-Fe₃O₄ NPs compared to bare Fe₃O₄ for the removal of MB dye. The MB removal efficiency of HA-Fe₃O₄ NPs was found to be proportional to amount of adsorbed HA. © VBRI Press.

Keywords

Humic acid, magnetite nanoparticles, co-precipitation, methylene blue, adsorption.