Adsorption of mercury(ii) with an Fe₃O₄ magnetic polypyrrole–graphene oxide nanocomposite

Abstract

To enhance the ability to remove mercury(II) from aqueous media, an Fe 3 O 4 magnetic nanocomposite (PPy-GO) composed of polypyrrole (PPy) and graphene oxide (GO) was synthesized in situ and characterized via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), zeta potential analysis, vibrating sample magnetometer (VSM) and the Brunauer-Emmett-Teller (BET) method. The performance of the magnetic PPy-GO for adsorbing mercury(II) from water along with the effects of solution pH, adsorbent dosage, coexisting ions, reaction time and temperature were studied in detail. The adsorption kinetics, isotherms and thermodynamics were investigated in detail to gain insights into the adsorption process. The results show that the BET surface area of the magnetic PPy-GO reached 1737.6 m 2 g À1. The Langmuir capacity of the magnetic PPy-GO for mercury(II) adsorption was 400.0 mg g À1 at 300 K and pH 7 AE 0.1.After adsorption, the magnetic PPy-GO nanocomposite could be efficiently separated from water via a magnetic field. The adsorption process was endothermic and spontaneous and occurred in accord with the Langmuir and pseudo-second-order models. The overall adsorption of mercury(II) not only involved chemisorption, but was also partially governed by intra-particle diffusion. Data from the preliminary application of magnetic PPy-GO to remove heavy metals from real electroplating effluent indicated a high removal efficiency of over 99% for mercury(II). Finally, a possible adsorption mechanism was discussed. All data showed that the magnetic PPy-GO material is a promising adsorbent to remove mercury(II) from aqueous media.

Recent Advances in Applications of Hybrid Graphene Materials for Metals Removal from Wastewater

“…Zhu et al fabricated a magnetic composite by polymerizing Fe 3 O 4 and adding it to graphene to develop polypyrrole-graphene (PPy-GO) nanocomposites [34]. Yang et al polymerized Lignosulfonate and Polyaniline with GO via ultrasonication and vigorous mixing in HCL to produce (LS-GO-PANI) [35].…”

“…High adsorption capacities of mercury in the range of 168-700 mg/g have been obtained with different graphene composites [34,36,47,[129][130][131][132][133][134]. L: Langmuir, F: Freundlich, T: Temkin, S: Sips, BET: Brunauer-Emmett-Teller.…”

CHARACTERIZATION-PERFORMANCE OF ZnO AND ZnO/ZnFe2O4 CATALYST USING ARTIFICIAL AND SOLAR LIGHT FOR MERCURY (II) REDUCTION

“…In addition, there is the speciation of Hg(II) adsorbate in aqueous medium with respect to pH: primarily Hg 2+ with some HgCl + (pH less than 4.0); predominance of HgCl 2 and traces of Hg(OH) 2 (pH 4-6); HgCl 2 . HgOH + , Hg 2 (OH) 3 + and less Hg(OH) 2 (pH 6-8); Hg(OH) 2 (pH greater than 8) (Zhou et al, 2017).…”

“…Nowadays, one of the main environmental problems is the increasing contamination of water bodies by an excess of heavy metals, such as mercury (Hg), which is not only an environmental hazard, but also a serious public health problem (Zhou et al, 2017;Mudasir et al, 2016;Botta et al2002).…”

An l-cystine/l-cysteine impregnated nanofiltration membrane with the superior performance of an anchoring heavy metal in wastewater

“…7,8 Therefore, there is a critical need to remove heavy metal ions from polluted water to maintain human and environmental well-being. [9][10][11] Among the methods of heavy metal remediation including chemical precipitation, 12 membrane separation, ion exchange, 13 and adsorption, [14][15][16] membrane separation is the most popularly used due to the advantages of smaller footprint, low-cost, elimination of chemical residuals, relative ease of scaling up, and environmental friendliness. [17][18][19] As one of the effective means of membrane process, the nanoltration (NF) technique, which combines the separation mechanisms of size exclusion and Donnan exclusion, has being widely used in drinking water and wastewater treatments because of the higher energy efficiency and simplicity of operation.…”