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. 2020 Jun 22;10(1):10076.
doi: 10.1038/s41598-020-67168-2.

Synthesis of diglycolic acid functionalized core-shell silica coated Fe3O4 nanomaterials for magnetic extraction of Pb(II) and Cr(VI) ions

Tehreema Nawaz  1 , Sonia Zulfiqar  2 , Muhammad Ilyas Sarwar  3 , Mudassir Iqbal  1
Affiliations

Synthesis of diglycolic acid functionalized core-shell silica coated Fe3O4 nanomaterials for magnetic extraction of Pb(II) and Cr(VI) ions

Tehreema Nawaz et al. Sci Rep. .

Abstract

Amine-terminated core-shell silica coated magnetite nanoparticles were functionalized with diglycolic acid for the first time to create acid moiety on the surface of the nanoparticles. The formation of magnetite nanoparticles was scrutinised through XRD, SEM, EDS, TEM, VSM and FTIR spectroscopy. The BET surface area of nano-sorbent was found to be 4.04 m2/g with pore size 23.68 nm. These nanomaterials were then utilized to remove the Pb(II) and Cr(VI) ions from their aqueous media and uptake of metal ions was determined by atomic absorption spectroscopy (AAS). A batch adsorption technique was applied to remove both ions at optimised pH and contact time with maximum adsorption efficiency for Pb(II) ions at pH 7 while for Cr(VI) ions at pH 3. Adsorption mechanism was studied using Langmuir and Freundlich isotherms and equilibrium data fitted well for both the isotherms, showing complex nature of adsorption comprising both chemisorption as well as physio-sorption phenomena. The nanosorbents exhibited facile separation by applying external magnetic field due to the ferrimagnetic behaviour with 31.65 emu/g saturation magnetization. These nanosorbents were also found to be used multiple times after regeneration.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Reaction scheme for synthesis of FGA-1.
Figure 2
Figure 2
FTIR spectra of Fe3O4, silica coated, amine and acid functionalized nanoparticles.
Figure 3
Figure 3
XRD patterns of (a) Fe3O4, (b) silica coated and (c) acid functionalized nanoparticles.
Figure 4
Figure 4
SEM images of (a) Fe3O4, (b) silica coated and (c) acid functionalized nanoparticles.
Figure 5
Figure 5
EDS spectra of (a) Fe3O4 and (b) acid functionalized nanoparticles.
Figure 6
Figure 6
TEM image of acid functionalized nanoparticles.
Figure 7
Figure 7
VSM measurements of Fe3O4 and acid functionalized nanoparticles.
Figure 8
Figure 8
Zeta potential measurement of FGA-1 at 25 °C.
Figure 9
Figure 9
N2 gas isotherms of FSA-1 and FGA-1 measured at 77 K.
Figure 10
Figure 10
Adsorption of metal ions as a function of time.
Figure 11
Figure 11
Adsorption of metal ions as a function of pH.
Figure 12
Figure 12
Adsorption of metal ions as a function of adsorbate concentration.
Figure 13
Figure 13
Langmuir isotherm for adsorption of Pb(II) ions by acid functionalized nanoparticles.
Figure 14
Figure 14
Langmuir isotherm for adsorption of Cr(VI) ions by acid functionalized nanoparticles.
Figure 15
Figure 15
Freundlich isotherm for adsorption of Pb(II) ions by acid functionalized nanoparticles.
Figure 16
Figure 16
Freundlich isotherm for adsorption of Cr(VI) ions by acid functionalized nanoparticles.
Figure 17
Figure 17
Adsorption capacity of Pb(II) and Cr(VI) ions on regeneration of acid functionalized nanoparticles.
See this image and copyright information in PMC

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