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Lianne Sheppard - One of the best experts on this subject based on the ideXlab platform.
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positive matrix factorizatIon of a 32 month series of daily pm2 5 speciatIon data with incorporatIon of temperature stratificatIon
Atmospheric Environment, 2013Co-Authors: Ricardo Piedrahita, Steven J Dutton, Jana B Milford, Joshua G Hemann, Jennifer L Peel, Shelly L Miller, Sverre Vedal, Lianne Sheppard, Michael P HanniganAbstract:Abstract This study presents source apportIonment results for PM2.5 from applying positive matrix factorizatIon (PMF) to a 32-month series of daily PM2.5 compositIonal data from Denver, CO, including concentratIons of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solutIon was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutIons with those from the base case solutIon. These eight factors were identified as Inorganic Ion, n-alkane, EC/sterane, light n-alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd n-alkane. The Inorganic Ion factor dominated the reconstructed PM2.5 mass (sulfate + nitrate + EC + OC) in cold periods (daily average temperature 20 °C; 53.1%). The two factors had comparable relative contributIons of 26.5% and 27.1% in warm periods with temperatures between 10 °C and 20 °C. Each of the seven factors resolved in a previous study ( Dutton et al., 2010b ) using a 1-year data set from the same locatIon matches one factor from the current work based on comparing factor profiles. Six out of the seven matched pairs of factors are linked to similar source classes as suggested by the strong correlatIons between factor contributIons (r = 0.89–0.98). Temperature-stratified source apportIonment was conducted for three subsets of the data in the current study, corresponding to the cold, warm and hot periods mentIoned above. The cold period (7-factor) solutIon exhibited a similar distributIon of reconstructed PM2.5 mass as the full data set solutIon. The factor contributIons of the warm period (7-factor) solutIon were well correlated with those from the full data set solutIon (r = 0.76–0.99). However, the reconstructed PM2.5 mass was distributed more to Inorganic Ion, n-alkane and medium alkane/alkanoic acid factors in the warm period solutIon than in the full data set solutIon. For the hot period (6-factor) solutIon, PM2.5 mass distributIon was quite different from that of the full data set solutIon, as illustrated by regressIon slopes as low as 0.2 and as high as 4.8 of each matched pair of factors across the two solutIons.
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positive matrix factorizatIon of a 32 month series of daily pm2 5 speciatIon data with incorporatIon of temperature stratificatIon
Atmospheric Environment, 2013Co-Authors: Mingjie Xie, Ricardo Piedrahita, Steven J Dutton, Jana B Milford, Joshua G Hemann, Jennifer L Peel, Shelly L Miller, Sverre Vedal, Sunyoung Kim, Lianne SheppardAbstract:Abstract This study presents source apportIonment results for PM 2.5 from applying positive matrix factorizatIon (PMF) to a 32-month series of daily PM 2.5 compositIonal data from Denver, CO, including concentratIons of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solutIon was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutIons with those from the base case solutIon. These eight factors were identified as Inorganic Ion, n -alkane, EC/sterane, light n -alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd n -alkane. The Inorganic Ion factor dominated the reconstructed PM 2.5 mass (sulfate + nitrate + EC + OC) in cold periods (daily average temperature 2.5 mass) whereas the summer/odd n -alkane factor dominated in hot periods (>20 °C; 53.1%). The two factors had comparable relative contributIons of 26.5% and 27.1% in warm periods with temperatures between 10 °C and 20 °C. Each of the seven factors resolved in a previous study ( Dutton et al., 2010b ) using a 1-year data set from the same locatIon matches one factor from the current work based on comparing factor profiles. Six out of the seven matched pairs of factors are linked to similar source classes as suggested by the strong correlatIons between factor contributIons ( r = 0.89–0.98). Temperature-stratified source apportIonment was conducted for three subsets of the data in the current study, corresponding to the cold, warm and hot periods mentIoned above. The cold period (7-factor) solutIon exhibited a similar distributIon of reconstructed PM 2.5 mass as the full data set solutIon. The factor contributIons of the warm period (7-factor) solutIon were well correlated with those from the full data set solutIon ( r = 0.76–0.99). However, the reconstructed PM 2.5 mass was distributed more to Inorganic Ion, n -alkane and medium alkane/alkanoic acid factors in the warm period solutIon than in the full data set solutIon. For the hot period (6-factor) solutIon, PM 2.5 mass distributIon was quite different from that of the full data set solutIon, as illustrated by regressIon slopes as low as 0.2 and as high as 4.8 of each matched pair of factors across the two solutIons.
Ricardo Piedrahita - One of the best experts on this subject based on the ideXlab platform.
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positive matrix factorizatIon of a 32 month series of daily pm2 5 speciatIon data with incorporatIon of temperature stratificatIon
Atmospheric Environment, 2013Co-Authors: Ricardo Piedrahita, Steven J Dutton, Jana B Milford, Joshua G Hemann, Jennifer L Peel, Shelly L Miller, Sverre Vedal, Lianne Sheppard, Michael P HanniganAbstract:Abstract This study presents source apportIonment results for PM2.5 from applying positive matrix factorizatIon (PMF) to a 32-month series of daily PM2.5 compositIonal data from Denver, CO, including concentratIons of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solutIon was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutIons with those from the base case solutIon. These eight factors were identified as Inorganic Ion, n-alkane, EC/sterane, light n-alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd n-alkane. The Inorganic Ion factor dominated the reconstructed PM2.5 mass (sulfate + nitrate + EC + OC) in cold periods (daily average temperature 20 °C; 53.1%). The two factors had comparable relative contributIons of 26.5% and 27.1% in warm periods with temperatures between 10 °C and 20 °C. Each of the seven factors resolved in a previous study ( Dutton et al., 2010b ) using a 1-year data set from the same locatIon matches one factor from the current work based on comparing factor profiles. Six out of the seven matched pairs of factors are linked to similar source classes as suggested by the strong correlatIons between factor contributIons (r = 0.89–0.98). Temperature-stratified source apportIonment was conducted for three subsets of the data in the current study, corresponding to the cold, warm and hot periods mentIoned above. The cold period (7-factor) solutIon exhibited a similar distributIon of reconstructed PM2.5 mass as the full data set solutIon. The factor contributIons of the warm period (7-factor) solutIon were well correlated with those from the full data set solutIon (r = 0.76–0.99). However, the reconstructed PM2.5 mass was distributed more to Inorganic Ion, n-alkane and medium alkane/alkanoic acid factors in the warm period solutIon than in the full data set solutIon. For the hot period (6-factor) solutIon, PM2.5 mass distributIon was quite different from that of the full data set solutIon, as illustrated by regressIon slopes as low as 0.2 and as high as 4.8 of each matched pair of factors across the two solutIons.
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positive matrix factorizatIon of a 32 month series of daily pm2 5 speciatIon data with incorporatIon of temperature stratificatIon
Atmospheric Environment, 2013Co-Authors: Mingjie Xie, Ricardo Piedrahita, Steven J Dutton, Jana B Milford, Joshua G Hemann, Jennifer L Peel, Shelly L Miller, Sverre Vedal, Sunyoung Kim, Lianne SheppardAbstract:Abstract This study presents source apportIonment results for PM 2.5 from applying positive matrix factorizatIon (PMF) to a 32-month series of daily PM 2.5 compositIonal data from Denver, CO, including concentratIons of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solutIon was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutIons with those from the base case solutIon. These eight factors were identified as Inorganic Ion, n -alkane, EC/sterane, light n -alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd n -alkane. The Inorganic Ion factor dominated the reconstructed PM 2.5 mass (sulfate + nitrate + EC + OC) in cold periods (daily average temperature 2.5 mass) whereas the summer/odd n -alkane factor dominated in hot periods (>20 °C; 53.1%). The two factors had comparable relative contributIons of 26.5% and 27.1% in warm periods with temperatures between 10 °C and 20 °C. Each of the seven factors resolved in a previous study ( Dutton et al., 2010b ) using a 1-year data set from the same locatIon matches one factor from the current work based on comparing factor profiles. Six out of the seven matched pairs of factors are linked to similar source classes as suggested by the strong correlatIons between factor contributIons ( r = 0.89–0.98). Temperature-stratified source apportIonment was conducted for three subsets of the data in the current study, corresponding to the cold, warm and hot periods mentIoned above. The cold period (7-factor) solutIon exhibited a similar distributIon of reconstructed PM 2.5 mass as the full data set solutIon. The factor contributIons of the warm period (7-factor) solutIon were well correlated with those from the full data set solutIon ( r = 0.76–0.99). However, the reconstructed PM 2.5 mass was distributed more to Inorganic Ion, n -alkane and medium alkane/alkanoic acid factors in the warm period solutIon than in the full data set solutIon. For the hot period (6-factor) solutIon, PM 2.5 mass distributIon was quite different from that of the full data set solutIon, as illustrated by regressIon slopes as low as 0.2 and as high as 4.8 of each matched pair of factors across the two solutIons.
K. G. Varshney - One of the best experts on this subject based on the ideXlab platform.
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the adsorptIon of phosphamidon on the surface of styrene supported zirconium iv tungstophosphate a thermodynamic study
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2000Co-Authors: Ram Niwas, Upma Gupta, Asif Khan, K. G. VarshneyAbstract:AdsorptIon thermodynamics has been studied on the beads of hybrid Inorganic Ion exchanger: styrene supported zirconium (IV) tungstophosphate for a pesticide phosphamidon at 30, 45 and 60°C. As a result some thermodynamic parameters like Freundlich constants, thermodynamic equilibrium constant (K0), standard free energy changes (ΔG0), standard enthalpy change (ΔH0) and standard entropy changes (ΔS0) have been evaluated.
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synthesis and Ion exchange behaviour of polyaniline sn iv arsenophosphate a polymeric Inorganic Ion exchanger
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999Co-Authors: Ram Niwas, Asif Ali Khan, K. G. VarshneyAbstract:IncorporatIon of a polymer material into an Inorganic Ion exchanger provides a class of hybrid Ion exchangers with a good Ion exchange capacity, high stability, reproducibility and selectivity for heavy metals. Such a type of Ion exchanger ‘polyaniline Sn(IV) arsenophosphate’ has been synthesized by mixing polyaniline into Inorganic material. This material is characterized using X-ray, IR, TGA studies in additIon to Ion exchange capacity, pH-titratIon, elutIon and distributIon behaviour. On the basis of distributIon studies, the material has been found to be highly selective for Pb(II). Kinetic study of exchange for the metal Ions has been performed and some physical parameters such as self diffusIon coefficient D0, energy Ea and entropy ΔS* of activatIon have been determined.
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Inorganic Ion Exchangers in Chemical Analysis
1991Co-Authors: Mohsin Qureshi, K. G. VarshneyAbstract:Historical Background of Inorganic Ion Exchangers, Their ClassificatIon and Present Status. Modern Theories of Ion Exchange and Ion Exchange Selectivity With Particular References to Zeolites. Insoluble Heteropolyacid Salts. Inorganic Ion Exchangers in Radio Chemical Analysis. Inorganic Ion Exchangers for Ion Selective Electrodes. Amorphous Inorganic Ion Exchangersillus.
Michael P Hannigan - One of the best experts on this subject based on the ideXlab platform.
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positive matrix factorizatIon of a 32 month series of daily pm2 5 speciatIon data with incorporatIon of temperature stratificatIon
Atmospheric Environment, 2013Co-Authors: Ricardo Piedrahita, Steven J Dutton, Jana B Milford, Joshua G Hemann, Jennifer L Peel, Shelly L Miller, Sverre Vedal, Lianne Sheppard, Michael P HanniganAbstract:Abstract This study presents source apportIonment results for PM2.5 from applying positive matrix factorizatIon (PMF) to a 32-month series of daily PM2.5 compositIonal data from Denver, CO, including concentratIons of sulfate, nitrate, bulk elemental carbon (EC) and organic carbon (OC), and 51 organic molecular markers (OMMs). An optimum 8-factor solutIon was determined primarily based on the interpretability of the PMF results and rate of matching factors from bootstrapped PMF solutIons with those from the base case solutIon. These eight factors were identified as Inorganic Ion, n-alkane, EC/sterane, light n-alkane/polycyclic aromatic hydrocarbon (PAH), medium alkane/alkanoic acid, PAH, winter/methoxyphenol and summer/odd n-alkane. The Inorganic Ion factor dominated the reconstructed PM2.5 mass (sulfate + nitrate + EC + OC) in cold periods (daily average temperature 20 °C; 53.1%). The two factors had comparable relative contributIons of 26.5% and 27.1% in warm periods with temperatures between 10 °C and 20 °C. Each of the seven factors resolved in a previous study ( Dutton et al., 2010b ) using a 1-year data set from the same locatIon matches one factor from the current work based on comparing factor profiles. Six out of the seven matched pairs of factors are linked to similar source classes as suggested by the strong correlatIons between factor contributIons (r = 0.89–0.98). Temperature-stratified source apportIonment was conducted for three subsets of the data in the current study, corresponding to the cold, warm and hot periods mentIoned above. The cold period (7-factor) solutIon exhibited a similar distributIon of reconstructed PM2.5 mass as the full data set solutIon. The factor contributIons of the warm period (7-factor) solutIon were well correlated with those from the full data set solutIon (r = 0.76–0.99). However, the reconstructed PM2.5 mass was distributed more to Inorganic Ion, n-alkane and medium alkane/alkanoic acid factors in the warm period solutIon than in the full data set solutIon. For the hot period (6-factor) solutIon, PM2.5 mass distributIon was quite different from that of the full data set solutIon, as illustrated by regressIon slopes as low as 0.2 and as high as 4.8 of each matched pair of factors across the two solutIons.
Abraham Clearfield - One of the best experts on this subject based on the ideXlab platform.
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separatIon of lanthanum hafnium barium and radiotracers yttrium 88 and barium 133 using crystalline zirconium phosphate and phosphonate compounds as prospective materials for a ra 223 radioisotope generator
Applied Radiation and Isotopes, 2011Co-Authors: Teresia Moller, Naima Bestaoui, Melissa Wierzbicki, Todd Adams, Abraham ClearfieldAbstract:Abstract Crystalline hybrid organic/Inorganic Ion exchangers based on zirconium phosphate and phosphonate compounds were evaluated for applicatIon in radium-223 generator for radiopharmaceutical applicatIons. Various compositIons were synthesized and the selectivity of these materials was determined for inactive lanthanum, hafnium and barium, and radiotracers yttrium-88 and barium-133. The hybrid materials show very efficient lanthanum/barium separatIon; the response for zirconium phosphate was even better. A small-scale column loaded with pelletized zirconium phosphate compound demonstrated excellent retentIon of 88Y and release of 133Ba.
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an assessment of Inorganic Ion exchange materials for the removal of strontium from simulated hanford tank wastes
Separation Science and Technology, 1999Co-Authors: Paul Sylvester, Elizabeth A Behrens, Gina M Graziano, Abraham ClearfieldAbstract:Several Inorganic Ion-exchange materials were evaluated for the removal of strontium from two simulated Hanford tank wastes (NCAW and 101SY-Cs5) using static batch experiments. Sodium titanium silicate, Na2Ti2O3SiO4·2H2O(NaTS), was the best material in NCAW with a K d of 2.7 × 105 mL/g at a volume-to-mass ratio of 200:1. In the 101SY-Cs5 simulant, strontium extractIon was more difficult due to the presence of complexants and consequently K ds were greatly reduced. Sodium nonatitanate, NaTi, performed best in the presence of these complexants and gave a K d of 295 mL/g, though none of the materials performed particularly well. Pellets suitable for column studies were synthesized and the Ion exchangers evaluated in column studies. Breakthrough curves correlated well with the K ds obtained from batch experiments with the sodium titanium silicate performing best in NCAW and a pelletized form of sodium nonatitanate performing best in 101SY-Cs5. Both the sodium titanate and the sodium titanosilicate performed b...
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the removal of strontium and cesium from simulated hanford groundwater using Inorganic Ion exchange materials
Solvent Extraction and Ion Exchange, 1998Co-Authors: Paul Sylvester, Abraham ClearfieldAbstract:ABSTRACT A number of Inorganic Ion exchange materials that are commercially available or under development were evaluated for the removal of strontium and cesium from a simulated groundwater found in the Hanford waste storage area using a groundwater simulant spiked with either 89Sr or 137 Cs. The most promising materials for strontium were found to be a sodium titanosilicate from Texas A&M University closely followed by two titanium silicate pharmacosiderites obtained from AlliedSignal. The most promising materials for the selective removal of cesium from the simulant was again the sodium titanosilicate followed by an alumina-pillared montmorillonite clay obtained from Laporte Industries Ltd. The Ion exchange kinetics were shown to be very rapid for both the titanosilicate and the pharmacosiderite, whilst the alumina-pillared montmorillonite had slower kinetics more comparable to those of the zeolite AW500.
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assessment of a sodium nonatitanate and pharmacosiderite type Ion exchangers for strontium and cesium removal from doe waste simulants
Environmental Science & Technology, 1998Co-Authors: Elizabeth A Behrens, Paul Sylvester, Abraham ClearfieldAbstract:Several Inorganic Ion exchangers were tested for 89Sr and 137Cs removal from simulated DOE aqueous defense wastes (NCAW and 101SY-Cs5) and a Hanford groundwater solutIon (N-springs). The materials used in this scoping study consisted of the three-dimensIonal tunnel-structured pharmacosiderites [M3H(AO)4(BO4)3·4−6H2O (M = H, K; A = Ti, Ge; B = Si, Ge)]; the layered sodium nonatitanate, Na4Ti9O20·xH2O; and two commercially available exchangers, AW-500 and clinoptilolite. 89Sr and 137Cs distributIon coef ficient (Kd) measurements showed that all of the synthetic exchangers removed at least 97% of the 89Sr from the N-springs groundwater simulant in a single static equilibratIon. This simulant also contained parts per millIon levels of Ca2+, Mg2+, K+, and Na+. Similarly, many of the same materials also efficiently removed 137Cs (>98%) from the same solutIon, except for sodium titanate, which exhibited the lowest Kd of 1210 mL/g for Cs+. These preliminary Kd values provide an indicatIon that these exchangers ma...
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evaluatIon of synthetic Inorganic Ion exchangers for cesium and strontium removal from contaminated groundwater and wastewater
Solvent Extraction and Ion Exchange, 1997Co-Authors: Anatoly I Bortun, Lyudmila N Bortun, Abraham ClearfieldAbstract:ABSTRACT The Ion exchange testing of 30 synthetic adsorbents including layered and framework polyvalent metal silicates and phosphates, as well as amorphous exchangers was carried out. Their selectivity to alkali and alkaline earth metal catIons in individual and complex solutIons was determined. Several exchangers were found to have high selectivity for cesium and strontium. These exchangers are sodium phlogopite, layered sodium titanium silicate Na2TiSi2O7·2H2O, framework niobium (Na2Nb4Si2O15·4H2O, tentative formula), zirconium (Na2ZrSi3O9·H2O) and titanium (Na2Ti2SiO7·2H2O) silicates, and a layered δ-tin phosphate (Sn(HPO4)·2H2O). For all these materials cesium and strontium Ion exchange capacities as a functIon of pH were determined. The effect of sodium, magnesium and calcium on Cs− and Sr2− Ions sorptIon was also studied over the concentratIon range 0.005 M - 1 0 M and the explanatIons for the phenomena observed were proposed based on the knowledge of the crystal structure of the exchangers. Testin...