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.
Highlights
Water contamination with heavy metals is a source of concern since the metal cations tend to accumulate within the environment [1]
The fabricated polyacrylamide-functionalized magnetic nanoparticles were characterized by SEM, Transmission electron microscopy (TEM), X-ray diffraction (XRD), and FTIR
TEM observation indicates that the carbon coating matrix surrounding the magnetic Fe3 O4 nanoparticles was homogenously distributed within the matrix
Summary
Water contamination with heavy metals is a source of concern since the metal cations tend to accumulate within the environment [1]. Rain and snow can wash toxic metal elements into lakes, reservoirs, and underground water [2]. Improvement of the adsorbents for higher adsorption ability for removal of metal cation pollution from water is required and considered a priority research topic. The traditional methods for metal pollution remediation include chemical precipitation, electro-flotation, ion exchange, reverse osmosis, and adsorption, which is the recommended method [5,6,7,8,9,10,11,12,13]. Nanostructure adsorbents have exhibited much higher efficiency and faster adsorption rates in water treatment when compared to traditional ones [14,15]. The main drawbacks of nanostructure adsorbents are the difficulty of their separation. Magnetic nanomaterials can be and rapidly separated from an aqueous solution under an external magnetic field due to their features of simplicity, efficiency, and sensitivity [16,17,18,19,20,21]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
