One-Step Carbon Coating and Polyacrylamide Functionalization of Fe3O4 Nanoparticles for Enhancing Magnetic Adsorptive-Remediation of Heavy Metals

Abstract

Magnetic nanoparticles are used in adsorptive removal of heavy metals from polluted wastewater. However, their poor stability in an acidic medium necessitates their protection with a coating layer. Coating magnetic nanoparticles with carbon showed proper protection but the heavy metal removal efficiency was slightly weak. However, to boost the removal efficiencies of surface functionalization, polyacrylamide was applied to carbon-coated Fe3O4 nanoparticles. In this paper, to facilitate the synthesis process, one-step carbon coating and polyacrylamide functionalization were conducted using the hydrothermal technique with the aim of enhancing the adsorptive removal capacity of Fe3O4 nanoparticles towards some heavy metals such as Cu(II), Ni(II), Co(II), and Cd(II). The results showed that the one-step process succeeded in developing a carbon coating layer and polyacrylamide functionality on Fe3O4 nanoparticles. The stability of the magnetic Fe3O4 nanoparticles as an adsorbent in an acidic medium was improved due to its resistance to the dissolution that was gained during carbon coating and surface functionalization with polyacrylamide. The adsorptive removal process was investigated in relation to various parameters such as pH, time of contact, metal ion concentrations, adsorbent dose, and temperature. The polyacrylamide functionalized Fe3O4 showed an improvement in the adsorption capacity as compared with the unfunctionalized one. The conditions for superior adsorption were obtained at pH 6; time of contact, 90 min; metal solution concentration, 200 mg/L; adsorbent dose, 0.3 g/L. The modeling of the adsorption data was found to be consistent with the pseudo-second-order kinetic model, which suggests a fast adsorption process. However, the equilibrium data modeling was consistent with both the Langmuir and Freundlich isotherms. Furthermore, the thermodynamic parameters of the adsorptive removal process, including ΔG°, ΔH°, and ΔS°, indicated a spontaneous and endothermic sorption process. The developed adsorbent can be utilized further for industrial-based applications.

Rapid and Sensitive Detection of Cardiac Troponin I for Point-of-Care Tests Based on Red Fluorescent Microspheres

“…Among them, silica microspheres were usually used as a carrier with functionalized surface modification, such as nano-gold and graphene oxide [ 18 ], for enhancing the signal. Fe 3 O 4 [ 19 ] and Co 3 O 4 [ 20 ] were also frequently applied to impart the functionality of magnetic enrichment and high catalytic activity. In order to conjugate the antibodies for immunoassay, some functional groups, such as carboxyl and amidogen, still need to be modified on those microsphere surface.…”

Multifunctional Magnetic Oxide Nanoparticle (MNP) Core-Shell: Review of Synthesis, Structural Studies and Application for Wastewater Treatment

“…Polymer-stabilized magnetic iron composites are achieved by heating at a high temperature in an oxygen-free environment. Carbon can effectively protect the Fe 3 O 4 sphere from corrosion by an acidic medium because its dense structure can block the penetration of hydrogen ions, it also adds very little to the mass of the composite [ 11 , 69 , 101 ]. The large molecular weight of polymer enhances the surface area of the composite, which is a viable property for biological and environmental applications.…”

“…Varying the ratio of TEOS and iron oxide controlled the size of the iron oxide-silica colloid via the Stober process [ 103 ]. The TEM analysis ( Figure 4 ) of polyacrylamide-functionalized magnetic oxide carbon-coated nanoparticles showed a homogenous distribution of the particle in the matrix; the composite also showed resistance to leaching in an acidic medium [ 11 ]. The polyacrylamide coating on the composite helped formed a dense anti-corrosive layer on the particles, as evident in the SEM image ( Figure 4 ).…”

“… SEM ( A ) and TEM ( B ) images of polyacrylamide-functionalized magnetite, showing a dense anti-corrosive surface and uniform distribution of magnetite nanoparticles in the polyacrylamide capping moiety [ 11 ]. …”

“…The shell components can be organic, inorganic or a blend of both. Silica, resin, alumina, polymers, polyelectrolytes, surfactants, carbon and hemoglobin have been utilized by various authors to modify superparamagnetic nanoparticles [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. Magnetic nanocomposites have been adapted as a green means of transport in biological and environmental media based on ease of operation and overall economic gains [ 13 ].…”