Coating Fe3O4 Magnetic Nanoparticles with Humic Acid for High Efficient Removal of Heavy Metals in Water

Humic acid (HA) coated Fe3O4 nanoparticles (Fe3O4/HA) were developed for the removal of toxic Hg(II), Pb(II), Cd(II), and Cu(II) from water. Fe3O4/HA were prepared by a coprecipitation procedure with cheap and environmentally friendly iron salts and HA. TOC and XPS analysis showed the as-prepared Fe...

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Published inEnvironmental science & technology Vol. 42; no. 18; pp. 6949 - 6954
Main Authors Liu, Jing-fu, Zhao, Zong-shan, Jiang, Gui-bin
Format Journal Article
LanguageEnglish
Published Washington, DC American Chemical Society 15.09.2008
Subjects
Adsorption
Applied sciences
Carbon
Environmental Restoration and Remediation
Exact sciences and technology
Ferric Compounds - chemistry
Humic Substances
Hydrogen-Ion Concentration
Kinetics
Magnetics
Metals, Heavy - isolation & purification
Nanoparticles - chemistry
Nanoparticles - ultrastructure
Pollution
Remediation and Control Technologies
Solutions
Spectrophotometry, Infrared
Water - chemistry
Organic matter
Nanoparticle
Adsorption capacity
Hydrodynamics
Ultrafine particle
Tap water
Modeling
Heavy metal
Transport process
Sorption
Transmission electron microscopy
Adsorption
Magnetic separation
Aerosols
Lead
Lixiviation
Air pollution
Magnetic field
Coprecipitation
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Summary:Humic acid (HA) coated Fe3O4 nanoparticles (Fe3O4/HA) were developed for the removal of toxic Hg(II), Pb(II), Cd(II), and Cu(II) from water. Fe3O4/HA were prepared by a coprecipitation procedure with cheap and environmentally friendly iron salts and HA. TOC and XPS analysis showed the as-prepared Fe3O4/HA contains ∼11% (w/w) of HA which are fractions abundant in O and N-based functional groups. TEM images and laser particle size analysis revealed the Fe3O4/HA (with ∼10 nm Fe3O4 cores) aggregated in aqueous suspensions to form aggregates with an average hydrodynamic size of ∼140 nm. With a saturation magnetization of 79.6 emu/g, the Fe3O4/HA can be simply recovered from water with magnetic separations at low magnetic field gradients within a few minutes. Sorption of the heavy metals to Fe3O4/HA reached equilibrium in less than 15 min, and agreed well to the Langmuir adsorption model with maximum adsorption capacities from 46.3 to 97.7 mg/g. The Fe3O4/HA was stable in tap water, natural waters, and acidic/basic solutions ranging from 0.1 M HCl to 2 M NaOH with low leaching of Fe (≤3.7%) and HA (≤5.3%). The Fe3O4/HA was able to remove over 99% of Hg(II) and Pb(II) and over 95% of Cu(II) and Cd(II) in natural and tap water at optimized pH. Leaching back of the Fe3O4/HA sorbed heavy metals in water was found to be negligible.
Bibliography:istex:C5BBC32739A0767E017D5359089FE464E712A447
Procedure of batch metal sorption (Figure S1); characterization of Fe3O4/HA and Fe3O4 including UV−vis spectra (Figure S2), XPS (Figure S3), pH of zero point charge (Figure S4), magnetization (Figure S5), TEM (Figure S6), and laser particle size analysis (Figure S7); sorption kinetics (Figure S8), effect of salinity on metal removal (Figure S8), adsorption isotherms of heavy metals (Figure S10), and effect of time on the leaching of Fe, HA and heavy metals from Fe3O4/HA laden with heavy metals (Table S1) are shown. This material is available free of charge via the Internet at http://pubs.acs.org.
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ObjectType-Article-1
SourceType-Scholarly Journals-1
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ISSN:0013-936X
1520-5851
DOI:10.1021/es800924c