Environmental Trans ort and Fate of port and Fate of Environmental Transp Nanomaterials Nanomaterials Gregory V. Lowry Gregory V. Lowry Associate Professor of Environmental Engineering Carnegie Mellon University, Pittsburgh, PA 15213-3890, USA R830898 R830898 Nanomaterials Nanomaterials Most active area of nanotechnology research Most active area of nanotechnology research Current or near term applications: Current or near term applications: – nano nano- -engineered TiO engineered TiO 2 for sunscreens and paints – 2 for sunscreens and paints – carbon nanotube composites in tires – carbon nanotube composites in tires – silica nanoparticles as solid lubricants – silica nanoparticles as solid lubricants – reagents for groundwater remediation reagents for groundwater remediation – – protein protein- -based nanomaterials in soaps, shampoos, based nanomaterials in soaps, shampoos, – and detergents. and detergents. M. R. Wiesner, G. V. Lowry, P. Alvarez, D. Dionysiou, and P. Biswas. Environ. Sci. Technol. (in press) Dr. Gregory V. Lowry 2 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 161 July 12-13, 2006 Washington DC
Dr. Gregory V. Lowry 3 of46 Dr. Gregory V. Lowry 4 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 162 July 12-13, 2006 Washington DC
Dr. Gregory V. Lowry 5 of46 Potential Risks Potential Risks Nanotechnology risks are largely unknown Nanotechnology risks are largely unknown Risk is a function of both exposure exposure and Risk is a function of both and toxicity toxicity Need to monitor Need to monitor – Exposure pathways – Exposure pathways – – Fate and transport in the environment Fate and transport in the environment – Toxicity Toxicity – Dr. Gregory V. Lowry 6 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 163 July 12-13, 2006 Washington DC
Environmental Cycling of Environmental Cycling of Nanomaterials Nanomaterials What are Is there harm? source Bioaccumulation or management biomagnification? alternatives? Fate Sources Transport Receptors 9 How do they travel? 9 Can they be transformed? 9 What factors affect 9 What do they become? mobility? 9 Do transformations affect toxicity? 9 What ‘compartment’ do they reside Dr. Gregory V. Lowry 7 of46 Sources Exposure Inhalation Point Workplace exposure -Manufacturing Ambient air -Landfills Ingestion -Wastewater effluent Food Drinking water Non - Point Incidental Wear / attrition of tires ,. Dermal Strom water runoff Sunscreen Wet deposition Cosmetics Surface water Photolysis Air Filtration Uptake Release UV Accumulation Coagulation & Sedimentation Air Aggregation Sand Filtration Groundwater : Bio - Removal transformation Wiesner et al. (2006) ES&T Transport / Transformation Dr. Gregory V. Lowry 8 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 164 July 12-13, 2006 Washington DC
Outline Outline Fate processes affecting the mobility of Fate processes affecting the mobility of nanomaterials in the environment nanomaterials in the environment – Aggregation Aggregation – – Attachment/filtration Attachment/filtration – Transformations Transformations – Abiotic (redox transformations, photolysis) – Abiotic (redox transformations, photolysis) – Biotransformation Biotransformation – Mobility in the environment Mobility in the environment – Groundwater – Groundwater – Surface water – Surface water Dr. Gregory V. Lowry 9 of46 Nanoparticle Aggregation Aggregation Nanoparticle Particles aggregate in water: Particles aggregate in water: – High Hamaker constant – High Hamaker constant- -i.e. attractive van der i.e. attractive van der Waals forces Waals forces – Chemical bonding Chemical bonding – – Hydrophobicity Hydrophobicity – – Magnetic attraction – Magnetic attraction Small particles have high diffusion Small particles have high diffusion coefficients and many collisions between coefficients and many collisions between particles particles Dr. Gregory V. Lowry 10 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 165 July 12-13, 2006 Washington DC
Nanoparticle Stabilization Nanoparticle Stabilization Charge Stabilization Charge Stabilization - - - - - - - - - - - - - Steric Stabilization Steric Stabilization Dr. Gregory V. Lowry 11 of46 Fullerene Aggregation in Water Fullerene Aggregation in Water 9 Cluster dimensions ranged from 25-500 nm 9 Stable suspensions ≤ 0.05M (NaCl) 9 No surface coatings Fortner, et al. (2005). C60 in Water: Nanocrystal Formation and Microbial Response. Environ. Sci. Technol. 39(11); 4307-4316. Dr. Gregory V. Lowry 12 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 166 July 12-13, 2006 Washington DC
0 ) Aggregation Nanoiron (Fe 0 Nanoiron (Fe ) Aggregation Φ =10 -5 Nanoiron sedimentation curves (1 mM NaCl) (~80 mg/L) 1-min 25 micron 9-min 25 micron 35-min ~40-140 micron diameter (D F =1.8) Phenrat et al. ES&T (submitted) Dr. Gregory V. Lowry 25 micron 13 of46 TiO 2 (30 nm) Aggregation TiO 2 (30 nm) Aggregation Degussa P25 TiO 2 Increasing Conc. Aggregate size is a function of time and concentration Long et al. (2006). Titanium Dioxide (P25) Produces Oxidative Stress in Immortalized Brain Microglia (BV2): Implication of Nanoparticle Neurotoxicity. ES&T (in press) Dr. Gregory V. Lowry 14 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 167 July 12-13, 2006 Washington DC
Nanoparticl Size and Sedimentation e Size and Sedimentation Nanoparticle Particle TiO 2 Sedimentation in DMEM concentration affects: 1. Size of aggregates formed 2. Stability of suspensions 3. Fate of the particles Dr. Gregory V. Lowry 15 of46 Attachment to Surfaces Attachment to Surfaces Attachment is an important fate process Attachment is an important fate process – Limits mobility in porous media Limits mobility in porous media – – May affect bioavailability May affect bioavailability – – May affect transformation/degradation – May affect transformation/degradation Function of particle (Hamaker Constant) Function of particle (Hamaker Constant) and its surface properties and its surface properties – Differences between NPs Differences between NPs – Dr. Gregory V. Lowry 16 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 168 July 12-13, 2006 Washington DC
QCM Monitors Nanomaterial Nanomaterial QCM Monitors Attachment to SiO 2 Surfaces Attachment to SiO 2 Surfaces Sand Grain Sand Grain Saleh et al. EES (in press) Dr. Gregory V. Lowry 17 of46 Attachment Limits Mobility Attachment Limits Mobility Inlet Time=1 min Monolayer of sand 26 μ m Outlet 1” Time=10 min 1/2” Nanoiron aggregates are Micro-fluidic filtered PDMS cell 26 μ m Saleh et al. EES (in press) Dr. Gregory V. Lowry 18 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 169 July 12-13, 2006 Washington DC
Nanomateri al Transformations Nanomaterial Transfor mations Fundamental Questions Fundamental Questions – How long do the particles last? How long do the particles last? – – What do they become? What do they become? – Abiotic transformations Abiotic transformations – Redox reactions Redox reactions – – Photolysis (not in groundwater) – Photolysis (not in groundwater) Biotransformations Biotransformations – Aerobic oxidations Aerobic oxidations – – Anaerobic reductions – Anaerobic reductions Dr. Gregory V. Lowry 19 of46 0 Nanoparticles Reactive Fe 0 Nanoparticles Reactive Fe Fe 0 Contaminants Nano Fe 0 is are reduced oxidized Fe 0 TCE Fe 3 O 4 Fe 0 Fe 3 O 4 Acetylene Fe 3 O 4 Lifetime depends on Oxidant loading, pH, H + and maybe microbial activity H 2 H + is reduced Liu et al, (2005) ES&T 39, 1338 Liu and Lowry, (2006) ES&T (submitted) Dr. Gregory V. Lowry 20 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 170 July 12-13, 2006 Washington DC
0 Lifetime Depends on Fe 0 Lifetime Depends on Fe Particle Type Particle Type + + → + + ↑ 0 2 Fe 2 H Fe H 2 Fe(B) ~1-2 weeks RNIP ~1 year Liu and Lowry (2006) ES&T (in revision) Liu et al., (2005) Chem Mat. 17, 5315. Dr. Gregory V. Lowry 21 of46 0 Lifetime Depends on pH Fe 0 Lifetime Depends on pH Fe RNIP ~2 weeks pH=6.5 ~1 year pH=8.9 Dr. Gregory V. Lowry 22 of46 NANOTECHNOLOGY AND OSWER Session 4: Fate and Transport of Nanomaterials New opportunities and challenges Dr. Gregory V. Lowry -- Presentation Slides 171 July 12-13, 2006 Washington DC
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