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. IOM 3 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-Fe 0 Industrial implications My concurrent and future work at UNSW Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13

Richard Crane, Interface Analysis Centre. IOM 3 Young Persons Lecture Competition, 3/02/10 My background Grew up in Dorset, England BSc Geoscience, University of Bristol, 2004 – 2008 PhD 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. IOM 3 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 years with pollution from complex chemicals, dense non-aqueous liquid phases (DNAPLs) and radioactive metals. UNICEF/WHO 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 ratio Quantum size effects Pore network penetration even for low k systems Subsurface 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. IOM 3 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. IOM 3 Young Persons Lecture Competition, 3/02/10 Remediation type Remediation TechnologyLimitation 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. IOM 3 Young Persons Lecture Competition, 08/02/ miles 50 miles Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13

Chemical speciesConcentration (mg L -1 ) Metals Cu0.023 Fe0.043 Mo0.045 U Ligands Cl HCO 3­ F-F NO PO SO Organics12.72 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: Environmental mineralogy – Microbial Interactions, Anthropogenic Influences, Contaminated Land and Waste Management. Mineralogical Society Series. 9 (2000) 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): 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), 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): 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), 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): 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), 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), 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), 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? U 4f XPS spectra for nano-Fe 0 after 24h reaction Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13

By what mechanism is U 6+ 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), 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

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), 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), 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), 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), Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13 Results: in-situ XPS

19.0 m 2 g m 2 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), Richard Crane, International Association of Hydrogeologists Presentation, 07/05/13 an increase in the Fe 0 +Fe 2+ /Fe 3+ and the Fe 2+ /Fe 3+ 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 Fe 0 + 2Fe 3+ → 3Fe 2+ E 0 = 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

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), Eh manipulation: 64.5 mV m -2 (nano-FeNi) 46.1 mV m -2 (nano-Fe 0 )

200 miles 50 miles 5000 L batch sorption experiments – is nano-Fe 0 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

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-Fe 0 cannot be easily recovered Nano-toxicology issues Advantages and disadvantages of the in-situ deployment of Nano-Fe 0

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, Noubactep, C., Care, S. and Crane, R.A. (2012). Nanoscale metallic iron for environmental remediation: prospects and limitations. Water Air Soil Pollut. 223, 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, 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, Crane R.A. and Noubactep, C. (2012): Elemental metals for environmental remediation: learning from hydrometallurgy. Fresenius Environ. Bull. 21, 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, 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, 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.