Dianne L. Poster

Measurement, standards, and data needs for CO2 capture materials: a critical review.

The commercial deployment of cost-effective carbon capture technology is hindered partially by the lack of a proper suite of materials-related measurements, standards, and data, which would provide critical information for the systematic design, evaluation, and performance of CO2 separation materials. Based on a literature search and conversations with the carbon capture community, we review the current status of measurements, standards, and data for the three major carbon capture materials in use today: solvents, solid sorbents, and membranes. We highlight current measurement, standards and data activities aimed to advance the development and use of carbon capture materials and major research needs that are critical to meet if innovation in carbon capture materials is to be achieved. The review reveals that although adsorbents are considered to have great potential to reduce carbon capture cost, there is no consensus on the experimental parameters to be used for evaluating sorbent properties. Another important finding is the lack of in situ experimental tools for the structural characterization of solid porous materials during CO2 adsorption, and computational methods that would enable a materials-by-design approach for their development.

Measurement of the particle-size distributions of semivolatile organic contaminants in the atmosphere.

A method using a Berner five-stage, low-pressure cascade impactor was developed to measure the particle-size distributions of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. Possible sampling artifacts that may occur when sampling semivolatile organic chemicals with this low-pressure particle impactor(e.g., absorption of vapors onto sampler surfaces or volatilization of analytes from collected particles under reduced pressures within the impactor) were quantified for a variety of PAHs in the laboratory. At 20°C, these artifacts were insignificant for the collection of PAHs with vapor pressures less than 10 -8 atm. Several samples collected at a rural site (Egbert, Ontario) and an urban location (Chicago, IL) demonstrate the utility of the Berner impactor to collect PAHs under a variety of field conditions. At both the rural and urban locations, sufficient quantities of particles were collected in the five aerodynamic equivalent diameter size ranges (0.04-0.14, 0.14-0.49, 0.49-1.7, 1.7-6, and 6-21 μm) during 12 h to provide detectable levels of PAHs. PAHs were most often associated with particles less than 1.7 μm in both the rural and urban areas based on a limited number of observations (N= 5).

Polycyclic aromatic hydrocarbons (PAHs) in a coal tar standard reference material—SRM 1597a updated

SRM 1597 Complex Mixture of Polycyclic Aromatic Hydrocarbons from Coal Tar, originally issued in 1987, was recently reanalyzed and reissued as SRM 1597a with 34 certified, 46 reference, and 12 information concentrations (as mass fractions) for polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASHs) including methyl-substituted PAHs and PASHs. The certified and reference concentrations (as mass fractions) were based on results of analyses of the coal tar material using multiple analytical techniques including gas chromatography/mass spectrometry on four different stationary phases and reversed-phase liquid chromatography. SRM 1597a is currently the most extensively characterized SRM for PAHs and PASHs.

Development and Analysis of Three Diesel Particulate-Related Standard Reference Materials for the Determination of Chemical, Physical, and Biological Characteristics

The National Institute of Standards and Technology (NIST) has recently issued three Standard Reference Materials (SRMs) related to diesel particulate matter: SRM 1650a, Diesel Particulate Matter; SRM 2975, Diesel Particulate Matter (Industrial Forklift); and SRM 1975, Diesel Particulate Extract. These three materials have certified and reference concentrations for selected polycyclic aromatic hydrocarbons (PAHs) including many alkyl-substituted compounds. SRM 1650a is the reissue of an existing material and SRMs 2975 and 1975 represent new materials. The characterization of the PAH content of these three diesel particulate-related SRMs is presented with a discussion of the approach for the certification of PAH concentrations. In addition, the physical and biological characterization of these materials is discussed. A review of customer reported uses of these SRMs in the chemical, physical, and biological sciences is also provided.

Determination of Methyl-Substituted Polycyclic Aromatic Hydrocarbons in Diesel Particulate-Related Standard Reference Materials

The concentrations of methyl-substituted polycyclic aromatic hydrocarbons (PAHs) in three diesel particulate-related Standard Reference Materials (SRMs) have been determined using multiple methods of analysis. These three SRMs--SRM 1650a, Diesel Particulate Matter; SRM 2975, Diesel Particulate Matter (Industrial Forklift); and SRM 1975, Diesel Particulate Extract--were recently issued by the National Institute of Standards and Technology. Each material has certified and reference concentrations for PAHs including many methyl-substituted compounds. Reference concentrations are available for 21 compounds in SRM 1650a, 20 compounds in SRM 2975, and 20 compounds in SRM 1975. The characterization of the methyl-substituted PAHs is described in this article in conjunction with a description of the relative distribution of the methyl-substituted PAHs in each material.

Applications of ionizing radiation to the remediation of materials contaminated with heavy metals and polychlorinated biphenyls

Abstract We have investigated the removal from water of heavy metals and chelated heavy metal compounds using electron beam and gamma radiation. Parameter analyses include the effect of dissolved oxygen and the influence of adding various buffers and radical scavengers. Complete removal (>99%) of mercury, lead and cadmium ions, both free and chelated within EDTA, was achieved using radiation doses ranging from 3–100 kGy. We have also studied the radiation induced degradation of polychlorinated biphenyls (PCBs) in aqueous-organic and aqueous micellar systems. Rates and extent of dechlorination have been quantified in different solution matrices; reaction by-products and intermediate species have been identified; and the influences of dissolved oxygen and pH have been evaluated. The presence of a carbonate buffer was observed to significantly enhance PCB dechlorination yields by reducing concentrations of H 3 O + . Ionizing radiation was effective in degrading PCBs in micellar solutions but scavenging of e aq − by the surfactant lowered reaction efficiencies.

Determination of PAHs in Combustion-Related Samples and in SRM 1597, Complex Mixture of PAHs from Coal Tar

Abstract Three types of combustion sample extracts, smokeless coal, smoky coal, and wood, were analyzed for a range of polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASH). Standard Reference Material (SRM) 1597, Complex Mixture of PAHs from Coal Tar, was also analyzed as a control sample and for the determination of a larger number of PAHs relative to those determined previously. Target analytes included many alkyl-substituted PAHs such as dimethylphenanthrenes, methylfluoranthenes, and methylpyrenes. The analytical methods included sample clean-up and the selection of specific stationary phases to accomplish unique separations of PAHs. Clean-up involved the use of normal-phase liquid chromatographic isolation of PAHs based on the number of aromatic carbons and a total PAH fraction, PAHs in the resulting fractions were separated by gas chromatography using two stationary phases with different selectivities and analyzed using mass spectrometry. These methods are discussed below and results are presented with an emphasis on the relative concentrations and distribution of PAHs in the combustion samples.

Chromatographic Methods of Analysis for the Determination of PAHs in Environmental Samples

Polycyclic aromatic hydrocarbons (PAHs) constitute a class of compounds that are known to exhibit mutagenic and carcinogenic properties. As a result, PAHs are frequently measured in environmental compartments such as the atmosphere, freshwater and marine surface waters and sediments, and in biological tissues and terrestrial matrices such as oyster tissue, soils, and vegetation. Measurements often require difficult analytical chemistry schemes because environmental PAHs typically lack distinct functional groups and exist with numerous structural isomers. Therefore, analytical methods must offer isolation, separation, and detection capabilities for compounds that exist as multi-component mixtures. The Analytical Chemistry Division at the National Institute of Standards and Technology (NIST) has been involved in the development and use of liquid and gas chromatography (LC and GC, respectively) methods for the determination of PAHs since the early 1970s as part of the development of standard reference materials (SRMs) for the measurement of PAHs in environmental samples. In this chapter, recent NIST experiences in the use of LC and GC methods for the determination of PAHs in environmental samples are presented. Specifically, LC and GC techniques are discussed including a review on the selection of an appropriate LC column for the separation of PAHs, approaches for the determination of PAHs in environmental samples by LC techniques (selective detection using fluorescence spectroscopy and isomer fractionation techniques), and conventional and novel GC techniques (PAH separations using phenylmethylpolysiloxane and liquid crystalline stationary phases, respectively). Case studies are presented for the determination of PAHs in a diesel particulate extract and two marine sediment standard references materials. The results of LC and GC measurements of PAHs are discussed, and the applicability of the various approaches are compared. In addition, coupled LC-GC and supercritical fluid chromatography (SFC) are examined as alternative approaches for the measurement of PAHs in environmental samples.

Radiolytic dechlorination of polychlorinated biphenyls in transformer oil and in marine sediment

Abstract Radiolytic dechlorination of polychlorinated biphenyls (PCBs) in transformer oil and in marine sediments has been studied. At low PCB concentrations, complete degradation of the PCBs in transformer oil was achieved without degradation of the oil. Addition of an organic base, triethylamine, enhances the radiolytic dechlorination yield. The mechanism of dechlorination has been shown to involve electron transfer to PCBs from various aromatic radical anions formed in the irradiated oil. At high PCB concentrations, large amounts of triethylamine were necessary to achieve complete radiolytic dechlorination. Preliminary results on PCB-contaminated marine sediments demonstrate that addition of 2-propanol to the sediment/water slurry increases the effectiveness of the electron beam treatment.

Recent Developments in NIST Standard Reference Materials for Polycyclic Aromatic Hydrocarbons in Environmental Matrices

Abstract The National Institute of Standards and Technology (NIST) has recently issued several new environmental matrix SRMs, including air and diesel particulate matter, marine sediment, and mussel tissue with certified and reference concentrations for polycyclic aromatic hydrocarbons (PAHs). New marine-related SRMs include: SRM 1944 New York/New Jersey Waterway Sediment, SRM 2974 Organics in Freeze-dried Mussel Tissue, SRM 2977 Mussel Tissue (Organic Contaminants and Trace Elements), and SRM 2978 Mussel Tissue (Organic Contaminants — Raritan Bay, New Jersey). SRM 2975 Diesel Particulate Matter (Industrial Forklift) and SRM 1975 Diesel Particulate Extract (a dichloromethane extract of the particulate matter used for SRM 2975) represent two new diesel particulate-related materials. In addition two existing materials, SRM 1649a Urban Dust and SRM 1650a Diesel Particulate Matter were recently reissued with certified and reference values for over 40 PAHs.