Removal of mercury(II) from contaminated water by gold-functionalised Fe3O4 magnetic nanoparticles

• Published in: Environmental technology Vol. 41; no. 8; pp. 959 - 970
• Main Authors: Maia, Luiz Fernando Oliveira, Santos, Mayra Soares, Andrade, Thainá Gusmão, Hott, Rodrigo de Carvalho, Faria, Márcia Cristina da Silva, Oliveira, Luiz Carlos Alves, Pereira, Márcio César, Rodrigues, Jairo Lisboa
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 02.04.2020; Taylor & Francis Ltd
• Subjects: Adsorption; Au nanoparticles; Coordination compounds; Ferric ions; Ferrous ions; functionalisation; Gold; Ionic strength; Iron oxides; Magnetite; Mercury; Mercury (metal); Mercury compounds; Nanoparticles; Organic chemistry; Resonance lines; Surface chemistry; Water pollution
• ISSN: 0959-3330; 1479-487X
• DOI: 10.1080/09593330.2018.1515989

Fe 3 O 4 nanoparticles were prepared by co-precipitation of Fe 2+ and Fe 3+ and then modified with Au to produce an effective adsorbent (Fe 3 O 4 /Au) for aqueous Hg(II) in contaminated water. Rietveld refinement on the XRD pattern confirmed that the Fe 3 O 4 /Au was synthesised. Mössbauer spectra exhibited broad and asymmetric resonance lines with two sextets which can be assigned to tetrahedral Fe 3+ ; and octahedral Fe 3+ /Fe 2+ . The quantitative analysis of magnetite confirms that the sample shows around 3 wt.% Au and 97 wt.% partially oxidised Fe 3 O 4 . High surface area: 121 m 2 g −1 , average pore sizes: 6.3 nm and pore volume: 1.64 cm 3 g −1 . The kinetics data were better fitted with a pseudo-second-order and Dubinin-Radushkevich isotherm suggests the Hg(II) adsorption onto Fe 3 O 4 /Au nanoparticles was mainly by chemical adsorption forming complex with the Au metal immobilised on Fe 3 O 4 surfaces. Adsorption capacity of 79.59 mg g −1 . Ionic strength and co-existing ions had a slight influence on the adsorption capacity.