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Direct Synthesis of Novel and Reactive Sulfide-modified Nano Iron through Nanoparticle Seeding for Improved Cadmium-Contaminated Water Treatment.

Su Y, Adeleye AS, Huang Y, Zhou X, Keller AA, Zhang Y - Sci Rep (2016)

Bottom Line: Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe(2+) to Fe(0) by 19%.Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe(0) crystals.The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China.

ABSTRACT
Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) is of great technical and scientific interest because of its promising application in groundwater remediation, although its synthesis is still a challenge. We develop a new nanoparticle seeding method to obtain a novel and reactive nanohybrid, which contains an Fe(0) core covered by a highly sulfidized layer under high extent of sulfidation. Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe(2+) to Fe(0) by 19%. X-ray adsorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure analyses demonstrate the hexahedral Fe-Fe bond (2.45 and 2.83 Å) formation through breaking down of the 1.99 Å Fe-O bond both in crystalline and amorphous iron oxide. The XANES analysis also shows 24.2% (wt%) of FeS with bond length of 2.4 Å in final nanohybrid. Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe(0) crystals. Nano-SiO2 seeding brings down the size of single Fe(0) grain from 32.4 nm to 18.7 nm, enhances final Fe(0) content from 5.9% to 55.6%, and increases magnetization from 4.7 to 65.5 emu/g. The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water.

No MeSH data available.


Related in: MedlinePlus

Structure evolution of particles in S-nZVI synthesis (A) FeSSi synthesis (B) (with seeding of 0.048 g nano-SiO2). Time value means the time after nucleation. The scale bar in images represents 200 nm except the one at 32 min in (B) (it represents 20 nm).
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f2: Structure evolution of particles in S-nZVI synthesis (A) FeSSi synthesis (B) (with seeding of 0.048 g nano-SiO2). Time value means the time after nucleation. The scale bar in images represents 200 nm except the one at 32 min in (B) (it represents 20 nm).

Mentions: TEM was employed to study the morphological change of the materials during the synthesis process (Fig. 2). For S-nZVI, the initial particles formed in solution were non-magnetic, whether or not seeding was done. This implies that these particles were not Fe0. In the second stage, there is an obvious difference between the systems with nanoparticle seeding and those without it; particles in systems without nanoparticle seeding were amorphous (Fig. 2A) while in the systems with seeding (Fig. 2B) they were heteromorphic (as suggested by the electron diffraction pattern). In the systems with nanoparticle seeding, flake-like structures were observed, suggesting that seeding can lower the surface free energy and facilitate the formation of flake-like structures rather than more compact spherical structures of pristine nZVI. Additionally, particles were non-magnetic in both systems during this stage, and the flake-like structure could be due to the presence of Cl−, which may function as a shape controller when incorporated into the iron cluster38.


Direct Synthesis of Novel and Reactive Sulfide-modified Nano Iron through Nanoparticle Seeding for Improved Cadmium-Contaminated Water Treatment.

Su Y, Adeleye AS, Huang Y, Zhou X, Keller AA, Zhang Y - Sci Rep (2016)

Structure evolution of particles in S-nZVI synthesis (A) FeSSi synthesis (B) (with seeding of 0.048 g nano-SiO2). Time value means the time after nucleation. The scale bar in images represents 200 nm except the one at 32 min in (B) (it represents 20 nm).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837343&req=5

f2: Structure evolution of particles in S-nZVI synthesis (A) FeSSi synthesis (B) (with seeding of 0.048 g nano-SiO2). Time value means the time after nucleation. The scale bar in images represents 200 nm except the one at 32 min in (B) (it represents 20 nm).
Mentions: TEM was employed to study the morphological change of the materials during the synthesis process (Fig. 2). For S-nZVI, the initial particles formed in solution were non-magnetic, whether or not seeding was done. This implies that these particles were not Fe0. In the second stage, there is an obvious difference between the systems with nanoparticle seeding and those without it; particles in systems without nanoparticle seeding were amorphous (Fig. 2A) while in the systems with seeding (Fig. 2B) they were heteromorphic (as suggested by the electron diffraction pattern). In the systems with nanoparticle seeding, flake-like structures were observed, suggesting that seeding can lower the surface free energy and facilitate the formation of flake-like structures rather than more compact spherical structures of pristine nZVI. Additionally, particles were non-magnetic in both systems during this stage, and the flake-like structure could be due to the presence of Cl−, which may function as a shape controller when incorporated into the iron cluster38.

Bottom Line: Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe(2+) to Fe(0) by 19%.Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe(0) crystals.The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China.

ABSTRACT
Magnetic sulfide-modified nanoscale zerovalent iron (S-nZVI) is of great technical and scientific interest because of its promising application in groundwater remediation, although its synthesis is still a challenge. We develop a new nanoparticle seeding method to obtain a novel and reactive nanohybrid, which contains an Fe(0) core covered by a highly sulfidized layer under high extent of sulfidation. Syntheses monitoring experiments show that seeding accelerates the reduction rate from Fe(2+) to Fe(0) by 19%. X-ray adsorption near edge structure (XANES) spectroscopy and extended X-ray absorption fine structure analyses demonstrate the hexahedral Fe-Fe bond (2.45 and 2.83 Å) formation through breaking down of the 1.99 Å Fe-O bond both in crystalline and amorphous iron oxide. The XANES analysis also shows 24.2% (wt%) of FeS with bond length of 2.4 Å in final nanohybrid. Both X-ray diffraction and Mössbauer analyses further confirm that increased nanoparticle seeding results in formation of more Fe(0) crystals. Nano-SiO2 seeding brings down the size of single Fe(0) grain from 32.4 nm to 18.7 nm, enhances final Fe(0) content from 5.9% to 55.6%, and increases magnetization from 4.7 to 65.5 emu/g. The synthesized nanohybrid has high cadmium removal capacity and holds promising prospects for treatment of metal-contaminated water.

No MeSH data available.


Related in: MedlinePlus