PerkinElmer: Characterizing Interaction of Nanoparticles with Organic Pollutants Using Coupling Thermal Analysis with Spectroscopic Techniques

Characterizing Interaction of Nanoparticles with Organic Pollutants Using Coupling Thermal Analysis with Spectroscopic Techniques E. Sahle-Demessie, Amy Zhao, U.S. Environmental Protection Agency Cincinnati, Ohio; Andrew W. Salamon, PerkinElmer Corp., Shelton, Connecticut 1 Introduction TGA Curves for Octano-Water-TiO2 partitioning of Phenathrene 100 There are more than a thousand products claiming containing Engineered Neat TiO2Nanoparticles (ENP) in biomedical, chemical, clothing, cosmetics, electronics, 95 wet TiO2 Controlenergy, environmental, food, materials and optical products. The effects of ENP on Weight percent, % 90 Run 4, w / lightthe environmental and human health are strongly related to their large surface-to-mass ratio and surface properties. Although the influence of natural colloids on the 85environment is well documented, we have limited understanding of fate, transport, 80 Run 5, w / Lighttoxicity and pollutant interaction of ENP. The tools to study these interactions are 75being develop. Run 4, No ligjt 70 2 Pollutants-Colloid Interaction 65 Run 5, No light 0 100 200 300 400 500 600 Many nanoparticles suspended in natural water come in contact with Temperature, oCpollutants and proteinaceous materials. The unique properties and behaviors of Figure 8. Absence of light made the nanoparticles less hydrophilic and increasedENP are strongly influenced by their physical-chemical characteristics, including the distribution to the organic phase.their high surface area relative to their volume, high interface energy and highsurface-to-charge ratio density. The partitioning and phase distribution of hazardous organic compounds 5 Summary Figure 2. Figure 4. Photographs of PerkinElmer TGA-GC-M System(HOC) can influence in the fate and bioavailability of the contaminants in aquatic • TGA-GC-MS a useful technique to study nanoparticle influence on adsorptionsystems and aquatic microorganisms significantly. There are a wide range of The physico-chemical properties relating to the environmental behavior of and partitioning PAHsorganic and inorganic pollutants that become associated with partitioning of HOC to hydrophobic organic compounds are mainly affected by the aqueous solubility and octanol-water partition coefficient. Aqueous solubility (Sw) is the equilibrium • Presence of nano-TiO2 increased the partitioning of PAHs to water phase.the particles. This partitioning has been shown to be inversely proportional to logsolubility of HOC and the log of particle concentration. Dynamics of nanoparticle- distribution of a solute between water and solute phases. In other words it is the • Nanoparticles resulted in increased partitioning of PAHs; six to ten times thanwater partitioning can significantly influence the speciation, and hence, maximum solute concentration possible at equilibrium, and it can function as a in water-octanol equilibrium conditionsunderstanding their fate, transport and toxicological impact of POPs such as PAHs, limiting factor in concentration dependent (for example, kinetic) processes The octanol-water partition coefficient is the ratio of the concentration of a chemical in • Naphthalene and phenanthrene have low water solubility but differingPCBs and is critical. The fate of organic pollutants in aquatic environment depends partitioning .largely on their partitioning behavior to nanoparticles and colloids. octanol and in water at equilibrium. Octanol is an organic solvent that is used as a surrogate for natural organic matter. This parameter is used in many • Partitioning influence increased at higher pH. environmental studies to help determine the fate of chemicals in the environment, such as to predict the extent a contaminant will bioaccumulate in fish. The octanol- • Absence of light made the nanoparticles less hydrophilic and increased the 7 distribution to the organic phase. water partition coefficient has been correlated to water solubility; therefore, the 6 Hexachlorobiphenyl . water solubility of a substance can be used to estimate its octanol-water partition Andrew W. Salamon, PerkinElmer Corp., Shelton, Connecticut; • Study suggested that the environmental risk of NP should include their Tetracene coefficient. The presence of nano-particles can influence the octanol-water Figure 5. Thermal Analysis of nano-TiO2, a) conOrganic pollutants adsorbed on transformation and influence in the transport of other pollutants. partitioning of hydrophobic organic water contaminants. nanoparticles: O-W Partitioning 5 Pyrene Methoxychlor Abundanc e 9-Methylanthracene Log Koc Anthracene 4 S c a n 1 7 9 7 (1 5 .6 2 2 min ): D 7 E xt# 5 b .D d a ta .ms 4 Phenanthrene Measurement Techniques 12000 10000 178 2-Methylnaphthalene 8000 We selected low molecular weight poly aromatic hydrocabons (PAHs) for this study 100 6000 3 including anthracene, naphthalene and phenanthrene as probe molecules to study 98 4000 2000 56 6976 84 Naphthalene 96 49 97 111 1926 139 1 1 151 163 70 1 185 197 the fate and transport of hydrophobic organic pollutants in water streams 94 Abundance 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 01 1 01 2 01 3 01 4 01 5 01 6 01 7 01 8 01 9 0 m/Tz-->D 7 E x t # 5 b . D d a t a . m s IC : 2 nanoparticles. The experimental procedure for this study involved the addition of 0- 2200000 92 2000000 B 1800000 Benzene 90 20 mg/l of PAHs in 200 ml of octanol to 900 ml of DI water containing different 88 1600000 1400000 1200000 1 concentrations of nanoparticles (ranging from 0-20 mg/l) in Erlenmeyer flask. After 86 1000000 800000 600000 1 2 3 4 5 6 7 stirring the flasks for 5 days the mixture was allowed to settle for 3 hours and then 84 400000 200000 the aqueous and octanol layers were separated. The aqueous suspensions were 82 A T im e --> 9 .5 0 1 0 .0 0 1 0 .5 0 1 1 .0 0 1 1 .5 0 1 2 .0 0 Log Kow 80 Additional Reading: divided into three portions. One portion will be extracted with equal volumes of 0 200 400 600 800 Temperature, oC Figure1. Suspended solid-Organic Carbon Partitioning Coefficient Versus Kow for methylene chloride (MC) and hexane. The mixture will be centrifuged and the PerkinElmer, Nanotechnology and Engineered Nanomaterials – A PolyCyclic Aromatic Hydrocarbons and Their Derivatives (Karickhoff et al, Water supernatant organic phase will be collected and injected into GC. The concentrations Primer, www.perkinelmer.com/nano Figure 6. TGA of phenatherene adsorption on nano-TiO2 at pH of 10 (curve A) Res., 241 (1979) of PAHs in MC and hexane and water were measured by Gas chromatography and 6.6 (Curve B) analysis. The second portion will be centrifuged at 10,000 rpm for 30 min. The PerkinElmer, Nanomaterials Reference Library 3 Pollutants sorbed on engineered nanoparticles mixture will be decanted and the settled nanoparticles will be put in crucible to dry in www.perkinelmer.com/nano oven (105 oC) for 8 hr. The mass fraction of the adsorbed organics on dried particles The sorption of pollutants on to nanoparticles in water phase will be the was analyzed using thermal gravimetric analyzer (PerkinElmer) and FTIR or TOC.result of three phase partitioning of pollutants between organic phase, water andsuspended solids. References:Octanol-Water Partition Coefficient (KOW) - "A coefficient representing the ratio ofthe solubility of a compound in octanol (a non-polar solvent) to its solubility in water 1. Bom, D., Andrews, R., Jacques, D., Anthony, J., Chen, B., Meier, M. S.,(a polar solvent). The higher to KOW, the more non-polar the compound. Kd is the Selegue, J. P., Thermogravimetric Analysis of the Oxidation of Multiwalled GC MSration of pollutant attached onto the particle and in the water phase. Phenanthrene Carbon Nanotubes: Evidence for the Role of Defects Sites in Carbon Naphthalene Nanotube Chemistry, NanoLetters, 2002, 2, 6, 615-619. Anthracene 2. Pinault, M, Mayne-L’Hermite, M., Reynaud, C., Beynaud, C., Beyssac, O.,Rouzaud, J.N., Clinard, C., Carbon nanotube produced by aerosol pyrolysis: growth mechanisms and post-annealing effects, (2004) 13, 1266- 1269Where Co, Cw and Cp are concentration of the pollutant organic compounds in the Figure 7. TGA –GC-MS Data with SEM imagenon-polar organic phase, in an equal weight of water, and concentration pollutants 3. Penn SG, He L and Natan MJ. Nanoparticles for bioanalysis. Currentattached on per mass of particles. Ideally these ratios are equilibrium partitioning of Figure 3. Schematic PerkinElmer TGA-GC-MS set-up with heated transfer capillary Opinion in Chemical Biology 2003, 7, 609-615pollutants between organic phase, dissolved in water phase and particulate phases. line. PerkinElmer, Inc., 940 Winter Street, Waltham, MA USA (800) 762-4000 or (+1) 203 925-4602 www.perkinelmer.com

PerkinElmer: Characterizing Interaction of Nanoparticles with Organic Pollutants Using Coupling Thermal Analysis with Spectroscopic Techniques

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