Nanoscale zero-valent iron: a new technology for groundwater remediation?
Richard Crane School of Civil and Environmental Engineering, University of New South Wales
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Richard Crane, Interface Analysis Centre. IOM3 Young Persons Lecture Competition, 3/02/10
Contents
My background and research interests
Why study environmental engineering?
Why research engineered nanoparticles?
Why zero-valent iron?
Hydro-geochemical characterisation of a contaminated mine site, SW Romania
Batch sorption experiments using the mine water
Improving the physio-chemical composition of nano-Fe0
Industrial implications
My concurrent and future work at UNSW
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Richard Crane, Interface Analysis Centre. IOM3 Young Persons Lecture Competition, 3/02/10
My background
Grew up in Dorset, England
BSc Geoscience, University of Bristol, 2004 – 2008PhD Geochemistry, University of Bristol, 2008 – 2012 Postdoctoral Research Fellow, University of Bristol, 2012 – 2013 Research Fellow, University of New South Wales, 2013 – present
Research interests:
Geochemistry and hydrology of groundwater systems
Applications include: environmental engineering; water quality and resource protection; mining and mine site management; waste management; and the use of engineered nanomaterials for environmental applications
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Why study environmental engineering?
Richard Crane, Interface Analysis Centre. IOM3 Young Persons Lecture Competition, 3/02/10
A side effect of our industrial success, the majority of which has occurred since the industrial revolution in the 1800’s.
The type of emissions has changed in the last 50-60 years with pollution from complex chemicals, dense non-aqueous liquid phases (DNAPLs) and radioactive metals.UNICEF/WHO. 2008. www.who.int/water_sanitation_health/monitoring/jmp_report_7_10_lores.pdf
Pollution by definition is toxic! WHO estimate that is contributes to 88% of the global burden of disease
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Why study engineered nanoparticles – its all about their size!
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Nanomaterial is defined as a material with at least one dimension <100nm
• A pin head: 2 mm = 2,000,000 nm• A human hair: 100 µm = 100,000 nm• A red blood cell: 10 µm = 10,000 nm• An E. Coli bacteria cell: 0.2 µm = 200 nm• A Rhinovirus (common cold): 25 nm• A DNA strand (width): 2 nm• A Glucose molecule: 1 nm
High surface area to volume ratioQuantum size effectsPore network penetration even for low k systemsSubsurface deployment as a colloidal suspension
Unique deployment mechanism for a sorption agent
Conventional PRB Nanoparticle injection
Crane, R A, Scott, T B. (2012) Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology. J Haz.Mat.. 211, 112–125.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Richard Crane, Interface Analysis Centre. IOM3 Young Persons Lecture Competition, 3/02/10
Why zero-valent iron?
Strong reducing agent
High sorption capacity
Non toxic
Cheap
Proven as effective for the reductive transformation of a wide variety of heavy metals, radionuclides, chlorinated organics, inorganic anions, and other harmful chemicals….
Crane, R A, Scott, T B. (2012) Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology. J Haz.Mat.. 211, 112–125.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Crane, R A, Scott, T B. (2012) Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology. J Haz.Mat.. 211, 112–125.
Deployment mechanism depends on the type of contaminant
Metal and metalloid contaminant remediation – immobilisation via sorption (adsorption, complexation, co-precipitation) and/or chemical reduction
Organic contaminant remediation – reductive transformation
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Richard Crane, Interface Analysis Centre. IOM3 Young Persons Lecture Competition, 3/02/10
Remediation type Remediation Technology Limitation
Ex-situ Pump-and-treat A, B, D
Excavation and disposal D, E
In-situ physical In-situ flushing N/A
Hydraulic fracturing N/A
In-situ chemical Permeable reactive barriers A, B, D, E
Chemical oxidation C
Nanoscale zero-valent iron injection
In-situ electrical Solidification, Stabilization and vitrification A, B, D, E
Electrokinetic processes A, B, D, E, F
In-situ biological Enzymatic remediation A, B, C, F
Phytoremediation A, B, C, F
Mycoremediation A, B, C, F
Microbial remediation A, B, C, F
Limitations
A= Lack in emplacement versatility
B= Long time lag
C= Only appropriate for specific contaminants
D= Expensive
E= Invasive
F= Low yield
Environmental engineering techniques
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Thesis title: Sorption of uranium onto nanoscale zero-valent iron particles
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Research goals:
Characterise the mechanisms and kinetics of uranium uptake onto nanoscale zero-valent iron
Application:
Determine the suitability of iron-based nanomaterials for the treatment of uranium contaminated waters and waste effluents
1. Hydro-geochemical characterisation of a contaminated site in SW Romania
2. Sorption experiments using natural and synthetic groundwater
3. Linking the recorded corrosion and contaminant uptake mechanisms to potential physico-chemical improvements for the different iron-based nanomaterials
NATO and Royal Society funded fieldwork in SW Romania
Richard Crane, Interface Analysis Centre. IOM3 Young Persons Lecture Competition, 08/02/10
200 miles
50 miles
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Chemical species Concentration (mg L-1)
Metals
Cu 0.023
Fe 0.043
Mo 0.045
U 0 - 10
Ligands
Cl- 35.01
HCO3 - 1041.10
F- 0.19
NO3- 30.80
PO43- 0.35
SO42- 0.25
Organics 12.72
Richard Crane, Interface Analysis Centre, 19/11/10
Geochemical analysis of the contaminated groundwater
K. V. Ragnarsdottir and L. Charlet. Uranium behaviour in natural environments. ISBN: 0-903-05620-8. Environmental mineralogy – Microbial Interactions, Anthropogenic Influences, Contaminated Land and Waste Management. Mineralogical Society Series. 9 (2000) 245-289.
U(IV) = insoluble
U(VI) = soluble
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Batch sorption experiments in vadose and phreatic zone conditions
Scott, T B, Popescu, I C, Crane R A, Noubactep C. (2011). Nano-scale metallic iron for the treatment of solutions containing multiple inorganic contaminants. J Haz.Mat. 186(1):280-287.Crane, R A., Dickinson, M., Popescu, I C., Scott, T B. (2011) Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water. Wat. Res. 45(9), 2931-2942.Crane, R A, Scott, T B. (2012) Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology. J Haz.Mat.. 211, 112–125.Crane, R A., Scott, T B. (In Press) The removal of uranium onto nanoscale zero-valent iron particles in anoxic batch systems. J Haz.Mat.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Scott, T B, Popescu, I C, Crane R A, Noubactep C. (2011). Nano-scale metallic iron for the treatment of solutions containing multiple inorganic contaminants. J Haz.Mat. 186(1):280-287.Crane, R A., Dickinson, M., Popescu, I C., Scott, T B. (2011) Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water. Wat. Res. 45(9), 2931-2942.Crane, R A, Scott, T B. (2012) Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology. J Haz.Mat.. 211, 112–125.Crane, R A., Scott, T B. (In Press) The removal of uranium onto nanoscale zero-valent iron particles in anoxic batch systems. J Haz.Mat.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Scott, T B, Popescu, I C, Crane R A, Noubactep C. (2011). Nano-scale metallic iron for the treatment of solutions containing multiple inorganic contaminants. J Haz.Mat. 186(1):280-287.Crane, R A., Dickinson, M., Popescu, I C., Scott, T B. (2011) Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water. Wat. Res. 45(9), 2931-2942.Crane, R A, Scott, T B. (2012) Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology. J Haz.Mat.. 211, 112–125.Crane, R A., Scott, T B. (In Press) The removal of uranium onto nanoscale zero-valent iron particles in anoxic batch systems. Env. Sci. Tech.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Crane, R A., Dickinson, M., Popescu, I C., Scott, T B. (2011) Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water. Water Research. 45(9), 2931-2942.Crane, R A., Scott, T B. (In Press) The removal of uranium onto nanoscale zero-valent iron particles in anoxic batch systems. J Haz.Mat.
What is causing the re-release?
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
U(IV) = insoluble
U(VI) = soluble
Crane, R A., Dickinson, M., Popescu, I C., Scott, T B. (2011) Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water. Water Research. 45(9), 2931-2942.Crane, R A., Scott, T B. (In Press) The removal of uranium onto nanoscale zero-valent iron particles in anoxic batch systems. J Haz.Mat.
What is causing the re-release?
U4f XPS spectra for nano-Fe0 after 24h reaction
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
By what mechanism is U6+ remobilised?
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Chemical reduction or complexation?
Crane, R A., Dickinson, M., Popescu, I C., Scott, T B. (2011) Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water. Water Research. 45(9), 2931-2942.Crane, R A., Scott, T B. (In Press) The removal of uranium onto nanoscale zero-valent iron particles in anoxic batch systems. J Haz.Mat.
Industrial/environmental implications
With ligands such as carbonate ubiquitous within the environment………
Previous studies using chemically simple systems have largely overestimated the performance of nanoscale iron for the treatment of environmental waters.
Contaminant re-release after a period of “apparent remediation” is a significant issue which may limit the development of zero-valent iron nanoparticles as a new technology for in-situ water treatment.
Zero-valent iron nanoparticles are only appropriate for the treatment of uranium in oxygen bearing waters if secondary methods (geotextile, bentonite, etc.) are applied to prevent oxygen ingress.
With sorption and/or chemical reduction a reversible process it is likely that the results from the current work is applicable to all heavy metals and radionuclides.
Methods are sought to improve the performance of nanoscale zerovalent iron for the remediation of chemically complex and/or oxygenated waters
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
TEM, XRD and XPS provide insight into the required improvements!
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Improvement options:
•Size
•Modify nanoparticle structure (crystallinity, grain size, oxide thickness, etc.) and/or surface chemistry (oxide phase and stoichiometry, oxide conductance, abundance of impurities, etc.)
•Add dopent material that would act to improve the corrosion properties of the nanoparticles – noble metals (Ni, Pd, Pt, Ag, etc.)
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Standard and vacuum annealed nanoparticle were analysed using BET, SEM, TEM, XPS, XRD, SIMS, STEM.
Option 1: Vacuum annealing
Scott, T. B., Dickinson, M., Crane, R,A., Riba, O., Hughes, G., Allen, G. (2009). The effects of vacuum annealing on the structure and surface chemistry of iron nanoparticles. Journal of Nanoparticle Research. 12(5), 1765-1775.Dickinson, M., Scott, T. B., Crane, R,A., Riba, O., Barnes, R.J., Hughes, G., (2009). The effects of vacuum annealing on the structure and surface chemistry of iron nickel nanoparticles. Journal of Nanoparticle Research. 12(6), 2081-2092.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Results: TEM, XRD and XPS
Scott, T. B., Dickinson, M., Crane, R,A., Riba, O., Hughes, G., Allen, G. (2009). The effects of vacuum annealing on the structure and surface chemistry of iron nanoparticles. Journal of Nanoparticle Research. 12(5), 1765-1775.Dickinson, M., Scott, T. B., Crane, R,A., Riba, O., Barnes, R.J., Hughes, G., (2009). The effects of vacuum annealing on the structure and surface chemistry of iron nickel nanoparticles. Journal of Nanoparticle Research. 12(6), 2081-2092.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Results: in-situ XPS
19.0 m2 g-1 4.8 m2 g-1
As-formed Vacuum annealed
Scott, T. B., Dickinson, M., Crane, R,A., Riba, O., Hughes, G., Allen, G. (2009). The effects of vacuum annealing on the structure and surface chemistry of iron nanoparticles. Journal of Nanoparticle Research. 12(5), 1765-1775.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
an increase in the Fe0+Fe2+/Fe3+
and the Fe2+/Fe3+ content of the bulk metallic core and oxide respectively;
migration and/or volatilisation of impurities;
improvement in the crystallinity of the bulk metallic core and oxide;
thinning and dehydration of the oxide
Fe0 + 2Fe3+ → 3Fe2+ E0 = 1.21 V
Comparative performance of the nanomaterials
Crane, R A., Scott, T B. (In Review). Vacuum annealing, a new method to improve the reactivity of nanoscale zerovalent iron particles. J. Haz. Mat.
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Significantly improved reactivity despite a 75% decrease in nanoparticle surface area
Option 2: Addition of a noble (cathodic) metal to improve galvanic properties
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Comparative performance of the nanomaterials
Dickinson, M., Scott, T. B., Crane, R,A., Riba, O., Barnes, R.J., Hughes, G., (2009). The effects of vacuum annealing on the structure and surface chemistry of iron nickel nanoparticles. Journal of Nanoparticle Research. 12(6), 2081-2092.
Eh manipulation: 64.5 mV m-2 (nano-FeNi) 46.1 mV m-2 (nano-Fe0)
200 miles
50 miles
5000 L batch sorption experiments – is nano-Fe0 a viable ex-situ technology?
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Implications for nanoparticle manufacture, storage and application
Nanoscale iron is highly effective for the rapid removal of uranium from groundwater despite the high carbonate concentrations.
For the removal of uranium from oxygenated (vadose zone) groundwater either “reactive” nano-iron is required or a secondary method to prevent DO ingress (geotextile, betonite, etc.)
Vacuum heat treatments and alloying of a noble metal have both been demonstrated as effective methods to improve the reactivity of nanoscale iron
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Advantages:
• Highly effective for a large range of organic and inorganic contaminants in laboratory test systems• Rapid, easy and versatile to deploy• Clean up is rapidly achieved• Limited environmental disruption• Lower cost than classic alternatives
Disadvantages (or areas for future research):
• Destroys organic contaminants BUT only immobilises heavy metals and radionuclides •Nano-Fe0 cannot be easily recovered• Nano-toxicology issues
Advantages and disadvantages of the in-situ deployment of Nano-Fe0
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Why am I at UNSW? Solute transport experiments using the NCGRT centrifuge facility
Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13
Thank you for your time
Crane, R.A. and Scott, T.B. (2012). Nanoscale zero-valent iron: future prospects for an emerging water treatment technology. J. Haz. Mater. 211, 112-125.
Noubactep, C., Care, S. and Crane, R.A. (2012). Nanoscale metallic iron for environmental remediation: prospects and limitations. Water Air Soil Pollut. 223, 1363-1382.
Scott, T.B., Popescu, I.C., Crane, R.A. and Noubactep, C. (2011). Nano-scale metallic iron for the treatment of solutions containing multiple inorganic contaminants. J. Hazard. Mat. 186, 280-287.
Crane, R.A., Dickinson, M., Popescu, I.C. and Scott, T.B. (2011). Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water. Water. Res. 45, 2931-2942.
Crane R.A. and Noubactep, C. (2012): Elemental metals for environmental remediation: learning from hydrometallurgy. Fresenius Environ. Bull. 21, 1192-1196.
Scott, T. B., Dickinson, M., Crane, R., Riba, O., Hughes, G. and Allen, G. (2010). The effects of vacuum annealing on the structure and surface chemistry of iron nanoparticles. J. Nano. Res. 12, 2081-2092.
Dickinson, M., Scott, T. B., Crane, R., Riba, O., Barnes, R., Hughes, G. (2010). The effects of vacuum annealing on the structure and surface chemistry of iron:nickel alloy nanoparticles. J. Nano. Res. 12, 2081-2092.
Crane, R A., Scott, T B. (In Press) The removal of uranium onto nanoscale zero-valent iron particles in anoxic batch systems. J Haz.Mater.
Crane, R A., Scott, T B. (Submitted for publication) Vacuum annealing, a new method to improve the reactivity of nanoscale zerovalent iron particles. J. Haz. Mater.
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