Combined Tween 20-Stabilized Gold Nanoparticles and Reduced Graphite Oxide–Fe₃O₄ Nanoparticle Composites for Rapid and Efficient Removal of Mercury Species from a Complex Matrix

Abstract

This study describes a simple method for removing mercuric ions (Hg(2+)) from a high-salt matrix based on the use of Tween-20-stabilized gold nanoparticles (Tween 20-Au NPs) as Hg(2+) adsorbents and composites of reduced graphite oxide and Fe3O4 NPs as NP collectors. Citrate ions adsorbed on the surface of the Tween 20-Au NPs reduced Hg(2+) to Hg(0), resulting in the deposition of Hg(0) on the surface of the NPs. To circumvent time-consuming centrifugation and transfer steps, the Hg(0)-containing gold NPs were collected using reduced graphite oxide-Fe3O4 NP composites. Compared with the reported NP-based methods for removing Hg(2+), Tween 20-Au NPs offered the rapid (within 30 min), efficient (>99% elimination efficiency), durable (>10 cycles), and selective removal of Hg(2+), CH3Hg(+), and C2H5Hg(+) in a high-salt matrix without the interference of other metal ions. This was attributed to the fact that the dispersed Tween 20-Au NPs exhibited large surface-area-to-volume ratio to bind Hg(2+) through Hg(2+)-Au(+) metallophilic interactions in a high-salt matrix. The formation of graphite oxide sheets and reduced graphite oxide-Fe3O4 NP composites was demonstrated using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectrometry, and transmission electron microscopy. The mechanism of interaction between Tween 20-Au NPs and Hg(2+) was studied using visible spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy.

Environmental implications and applications of engineered nanoscale magnetite and its hybrid nanocomposites: A review of recent literature

“…Citrate ions adsorbed on the surface of the Tween 20-Au NPs reduce Hg 2+ to Hg 0 , resulting in the deposition of Hg 0 on the surface of the NPs. Compared with the reported NP-based methods for removing Hg 2+ , Tween 20-Au NPs offer the rapid (within 30 min), efficient (>99% elimination efficiency), durable (>10 cycles), and selective removal of Hg 2+ , CH3Hg + , and C2H5Hg + in a high-salt matrix without the interference of other metal ions [334]. A novel magnetic composite microsphere (MCM) based on polyacrylamide (PAM)-grafted chitosan and silica-coated MNPs (CS-PAM-MCM) has been applied as an efficient adsorbent for the removal of Hg 2+ , Pb 2+ , and Cu 2+ in respective single, binary, and ternary metal systems.…”

Red-to-blue colorimetric detection of chromium via Cr (III)-citrate chelating based on Tween 20-stabilized gold nanoparticles

“…5A, compared 2+ , could not affected the detection of 1.0 M Cr (VI). In addition, as we know, Hg 2+ could be reduced to Hg (0) and formed Hg-Au alloys [31,32], which may disturb the surface of Au NPs. However, in this sensing method, 100 M of Hg 2+ could not interfere with the detection process.…”

In vivo assessment of bone marrow toxicity by gold nanoparticle-based bioconjugates in Crl:CD1(ICR) mice

“…21 In the current research, we aimed to investigate the biodistribution of GNPs capped with Tween ® 20 in vivo, as Tween ® 20 is one of the most efficient coating systems of colloidal Au which is a precursor for conjugation with various drugs used in the clinic. 22,23 Moreover, Tween ® 20 is uptaken preferentially by the reticuloendothelial system, 24 also known as the mononuclear phagocyte system. The reticuloendothelial system holds important immune functions and is located in reticular connective tissues of the spleen, lymph nodes, bone marrow, and liver.…”