The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
M. Singh - One of the best experts on this subject based on the ideXlab platform.
-
Studies on TiO2/ZnO photocatalysed degradation of lignin
Journal of Hazardous Materials, 2008Co-Authors: S.k. Kansal, M. SinghAbstract:Abstract The photocatalytic degradation of lignin obtained from wheat straw kraft digestion has been investigated by using TiO2 and ZnO semiconductors. ZnO has been found to be a better photocatalyst than TiO2. The different variables studied, include catalyst dose, solution pH, Oxidant Concentration and initial Concentration of the substrate. The degradation of lignin was favorable at pH 11. Optimum values of catalyst dose and Oxidant Concentration were found to be 1 g/l and 12.2 × 10−6 M, respectively. The degradation of the organic compound was also evaluated as COD removal and increase in the COD removal was observed with increase in degradation rate. An attempt has also been made to explore the applicability of ZnO in immobilized mode for the degradation of lignin under solar light for industrial scale application. Further the comparative evaluation of ZnO in slurry/immobilized mode has been carried out.
-
studies on tio2 zno photocatalysed degradation of lignin
Journal of Hazardous Materials, 2008Co-Authors: S.k. Kansal, M. SinghAbstract:Abstract The photocatalytic degradation of lignin obtained from wheat straw kraft digestion has been investigated by using TiO 2 and ZnO semiconductors. ZnO has been found to be a better photocatalyst than TiO 2 . The different variables studied, include catalyst dose, solution pH, Oxidant Concentration and initial Concentration of the substrate. The degradation of lignin was favorable at pH 11. Optimum values of catalyst dose and Oxidant Concentration were found to be 1 g/l and 12.2 × 10 −6 M, respectively. The degradation of the organic compound was also evaluated as COD removal and increase in the COD removal was observed with increase in degradation rate. An attempt has also been made to explore the applicability of ZnO in immobilized mode for the degradation of lignin under solar light for industrial scale application. Further the comparative evaluation of ZnO in slurry/immobilized mode has been carried out.
-
Studies on TiO(2)/ZnO photocatalysed degradation of lignin.
Journal of hazardous materials, 2007Co-Authors: S.k. Kansal, M. SinghAbstract:The photocatalytic degradation of lignin obtained from wheat straw kraft digestion has been investigated by using TiO(2) and ZnO semiconductors. ZnO has been found to be a better photocatalyst than TiO(2). The different variables studied, include catalyst dose, solution pH, Oxidant Concentration and initial Concentration of the substrate. The degradation of lignin was favorable at pH 11. Optimum values of catalyst dose and Oxidant Concentration were found to be 1g/l and 12.2 x 10(-6) M, respectively. The degradation of the organic compound was also evaluated as COD removal and increase in the COD removal was observed with increase in degradation rate. An attempt has also been made to explore the applicability of ZnO in immobilized mode for the degradation of lignin under solar light for industrial scale application. Further the comparative evaluation of ZnO in slurry/immobilized mode has been carried out.
D R Worsnop - One of the best experts on this subject based on the ideXlab platform.
-
effect of Oxidant Concentration exposure time and seed particles on secondary organic aerosol chemical composition and yield
Atmospheric Chemistry and Physics, 2015Co-Authors: Andrew T Lambe, P S Chhabra, T B Onasch, W H Brune, J F Hunter, Jesse H Kroll, M J Cummings, J F Brogan, Y Parmar, D R WorsnopAbstract:We performed a systematic intercomparison study of the chemistry and yields of secondary organic aerosol (SOA) generated from OH oxidation of a common set of gas- phase precursors in a Potential Aerosol Mass (PAM) contin- uous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH con- centrations ranging from 2:0 10 8 to 2:2 10 10 molec cm 3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH Concentrations ranging from 2 10 6 to 2 10 7 molec cm 3 over exposure times of several hours. The OH Concentration in the chamber experi- ments is close to that found in the atmosphere, but the inte- grated OH exposure in the flow reactor can simulate atmo- spheric exposure times of multiple days compared to cham- ber exposure times of only a day or so. In most cases, for a specific SOA type the most-oxidized chamber SOA and the least-oxidized flow reactor SOA have similar mass spectra, oxygen-to-carbon and hydrogen-to-carbon ratios, and carbon oxidation states at integrated OH exposures between approx- imately 1 10 11 and 2 10 11 molec cm 3 s, or about 1-2 days of equivalent atmospheric oxidation. This observation suggests that in the range of available OH exposure overlap for the flow reactor and chambers, SOA elemental compo- sition as measured by an aerosol mass spectrometer is sim- ilar whether the precursor is exposed to low OH concentra- tions over long exposure times or high OH Concentrations over short exposure times. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemi- cal composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors rather than het- erogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than mea- sured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.
-
comparison of secondary organic aerosol formed with an aerosol flow reactor and environmental reaction chambers effect of Oxidant Concentration exposure time and seed particles on chemical composition and yield
Atmospheric Chemistry and Physics, 2014Co-Authors: Andrew T Lambe, P S Chhabra, T B Onasch, W H Brune, J F Hunter, Jesse H Kroll, M J Cummings, J F Brogan, Y Parmar, D R WorsnopAbstract:We performed a systematic intercomparison study of the chemistry and yields of SOA generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH Concentrations ranging from 2.0×108 to 2.2×1010 molec cm-3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH Concentrations ranging from 2×106 to 2×107 molec cm-3 over exposure times of several hours. The OH Concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. A linear correlation analysis of the mass spectra (m=0.91–0.92, r2=0.93–0.94) and carbon oxidation state (m=1.1, r2=0.58) of SOA produced in the flow reactor and environmental chambers for OH exposures of approximately 1011 molec cm-3 s suggests that the composition of SOA produced in the flow reactor and chambers is the same within experimental accuracy as measured with an aerosol mass spectrometer. This similarity in turn suggests that both in the flow reactor and more » in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors, rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used. « less
S.k. Kansal - One of the best experts on this subject based on the ideXlab platform.
-
Studies on the photocatalytic degradation of 2,3-dichlorophenol using different Oxidants in aqueous solutions
Reaction Kinetics and Catalysis Letters, 2009Co-Authors: S.k. Kansal, Gurpreet Kaur, Sukhjinder SinghAbstract:In the present study, the photocatalytic degradation of 2,3-dichlorophenol(2,3-DCP) has been investigated in a batch reactor under UV light in slurry mode using titania P-25 (surface area 50 m2/g) as a photocatalyst and H2O2/NaOCl as Oxidants. The variables studied include catalyst dose, solution pH, Oxidant Concentration and initial substrate Concentration. The rate of degradation was studied in terms of changes in the Concentration of the pollutants and reduction in chemical oxygen demand. The degradation rate of (2,3-DCP) was favorable at acidic pH with both Oxidants. The optimum value of catalyst dose and Oxidant Concentration was found to be 0.75 g/L and 10 mM. The disappearance of 2,3-DCP obeyed pseudo-first order kinetics and the rate constant values were found to be 1.06 × 10−3s−1 and 8.7 × 10−4s−1 for TiO2 + H2O2 and TiO2 + NaOCl respectively.
-
Studies on TiO2/ZnO photocatalysed degradation of lignin
Journal of Hazardous Materials, 2008Co-Authors: S.k. Kansal, M. SinghAbstract:Abstract The photocatalytic degradation of lignin obtained from wheat straw kraft digestion has been investigated by using TiO2 and ZnO semiconductors. ZnO has been found to be a better photocatalyst than TiO2. The different variables studied, include catalyst dose, solution pH, Oxidant Concentration and initial Concentration of the substrate. The degradation of lignin was favorable at pH 11. Optimum values of catalyst dose and Oxidant Concentration were found to be 1 g/l and 12.2 × 10−6 M, respectively. The degradation of the organic compound was also evaluated as COD removal and increase in the COD removal was observed with increase in degradation rate. An attempt has also been made to explore the applicability of ZnO in immobilized mode for the degradation of lignin under solar light for industrial scale application. Further the comparative evaluation of ZnO in slurry/immobilized mode has been carried out.
-
studies on tio2 zno photocatalysed degradation of lignin
Journal of Hazardous Materials, 2008Co-Authors: S.k. Kansal, M. SinghAbstract:Abstract The photocatalytic degradation of lignin obtained from wheat straw kraft digestion has been investigated by using TiO 2 and ZnO semiconductors. ZnO has been found to be a better photocatalyst than TiO 2 . The different variables studied, include catalyst dose, solution pH, Oxidant Concentration and initial Concentration of the substrate. The degradation of lignin was favorable at pH 11. Optimum values of catalyst dose and Oxidant Concentration were found to be 1 g/l and 12.2 × 10 −6 M, respectively. The degradation of the organic compound was also evaluated as COD removal and increase in the COD removal was observed with increase in degradation rate. An attempt has also been made to explore the applicability of ZnO in immobilized mode for the degradation of lignin under solar light for industrial scale application. Further the comparative evaluation of ZnO in slurry/immobilized mode has been carried out.
-
Studies on TiO(2)/ZnO photocatalysed degradation of lignin.
Journal of hazardous materials, 2007Co-Authors: S.k. Kansal, M. SinghAbstract:The photocatalytic degradation of lignin obtained from wheat straw kraft digestion has been investigated by using TiO(2) and ZnO semiconductors. ZnO has been found to be a better photocatalyst than TiO(2). The different variables studied, include catalyst dose, solution pH, Oxidant Concentration and initial Concentration of the substrate. The degradation of lignin was favorable at pH 11. Optimum values of catalyst dose and Oxidant Concentration were found to be 1g/l and 12.2 x 10(-6) M, respectively. The degradation of the organic compound was also evaluated as COD removal and increase in the COD removal was observed with increase in degradation rate. An attempt has also been made to explore the applicability of ZnO in immobilized mode for the degradation of lignin under solar light for industrial scale application. Further the comparative evaluation of ZnO in slurry/immobilized mode has been carried out.
Andrew T Lambe - One of the best experts on this subject based on the ideXlab platform.
-
effect of Oxidant Concentration exposure time and seed particles on secondary organic aerosol chemical composition and yield
Atmospheric Chemistry and Physics, 2015Co-Authors: Andrew T Lambe, P S Chhabra, T B Onasch, W H Brune, J F Hunter, Jesse H Kroll, M J Cummings, J F Brogan, Y Parmar, D R WorsnopAbstract:We performed a systematic intercomparison study of the chemistry and yields of secondary organic aerosol (SOA) generated from OH oxidation of a common set of gas- phase precursors in a Potential Aerosol Mass (PAM) contin- uous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH con- centrations ranging from 2:0 10 8 to 2:2 10 10 molec cm 3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH Concentrations ranging from 2 10 6 to 2 10 7 molec cm 3 over exposure times of several hours. The OH Concentration in the chamber experi- ments is close to that found in the atmosphere, but the inte- grated OH exposure in the flow reactor can simulate atmo- spheric exposure times of multiple days compared to cham- ber exposure times of only a day or so. In most cases, for a specific SOA type the most-oxidized chamber SOA and the least-oxidized flow reactor SOA have similar mass spectra, oxygen-to-carbon and hydrogen-to-carbon ratios, and carbon oxidation states at integrated OH exposures between approx- imately 1 10 11 and 2 10 11 molec cm 3 s, or about 1-2 days of equivalent atmospheric oxidation. This observation suggests that in the range of available OH exposure overlap for the flow reactor and chambers, SOA elemental compo- sition as measured by an aerosol mass spectrometer is sim- ilar whether the precursor is exposed to low OH concentra- tions over long exposure times or high OH Concentrations over short exposure times. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemi- cal composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors rather than het- erogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than mea- sured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.
-
comparison of secondary organic aerosol formed with an aerosol flow reactor and environmental reaction chambers effect of Oxidant Concentration exposure time and seed particles on chemical composition and yield
Atmospheric Chemistry and Physics, 2014Co-Authors: Andrew T Lambe, P S Chhabra, T B Onasch, W H Brune, J F Hunter, Jesse H Kroll, M J Cummings, J F Brogan, Y Parmar, D R WorsnopAbstract:We performed a systematic intercomparison study of the chemistry and yields of SOA generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH Concentrations ranging from 2.0×108 to 2.2×1010 molec cm-3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH Concentrations ranging from 2×106 to 2×107 molec cm-3 over exposure times of several hours. The OH Concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. A linear correlation analysis of the mass spectra (m=0.91–0.92, r2=0.93–0.94) and carbon oxidation state (m=1.1, r2=0.58) of SOA produced in the flow reactor and environmental chambers for OH exposures of approximately 1011 molec cm-3 s suggests that the composition of SOA produced in the flow reactor and chambers is the same within experimental accuracy as measured with an aerosol mass spectrometer. This similarity in turn suggests that both in the flow reactor and more » in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors, rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used. « less
P S Chhabra - One of the best experts on this subject based on the ideXlab platform.
-
effect of Oxidant Concentration exposure time and seed particles on secondary organic aerosol chemical composition and yield
Atmospheric Chemistry and Physics, 2015Co-Authors: Andrew T Lambe, P S Chhabra, T B Onasch, W H Brune, J F Hunter, Jesse H Kroll, M J Cummings, J F Brogan, Y Parmar, D R WorsnopAbstract:We performed a systematic intercomparison study of the chemistry and yields of secondary organic aerosol (SOA) generated from OH oxidation of a common set of gas- phase precursors in a Potential Aerosol Mass (PAM) contin- uous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH con- centrations ranging from 2:0 10 8 to 2:2 10 10 molec cm 3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH Concentrations ranging from 2 10 6 to 2 10 7 molec cm 3 over exposure times of several hours. The OH Concentration in the chamber experi- ments is close to that found in the atmosphere, but the inte- grated OH exposure in the flow reactor can simulate atmo- spheric exposure times of multiple days compared to cham- ber exposure times of only a day or so. In most cases, for a specific SOA type the most-oxidized chamber SOA and the least-oxidized flow reactor SOA have similar mass spectra, oxygen-to-carbon and hydrogen-to-carbon ratios, and carbon oxidation states at integrated OH exposures between approx- imately 1 10 11 and 2 10 11 molec cm 3 s, or about 1-2 days of equivalent atmospheric oxidation. This observation suggests that in the range of available OH exposure overlap for the flow reactor and chambers, SOA elemental compo- sition as measured by an aerosol mass spectrometer is sim- ilar whether the precursor is exposed to low OH concentra- tions over long exposure times or high OH Concentrations over short exposure times. This similarity in turn suggests that both in the flow reactor and in chambers, SOA chemi- cal composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors rather than het- erogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than mea- sured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used.
-
comparison of secondary organic aerosol formed with an aerosol flow reactor and environmental reaction chambers effect of Oxidant Concentration exposure time and seed particles on chemical composition and yield
Atmospheric Chemistry and Physics, 2014Co-Authors: Andrew T Lambe, P S Chhabra, T B Onasch, W H Brune, J F Hunter, Jesse H Kroll, M J Cummings, J F Brogan, Y Parmar, D R WorsnopAbstract:We performed a systematic intercomparison study of the chemistry and yields of SOA generated from OH oxidation of a common set of gas-phase precursors in a Potential Aerosol Mass (PAM) continuous flow reactor and several environmental chambers. In the flow reactor, SOA precursors were oxidized using OH Concentrations ranging from 2.0×108 to 2.2×1010 molec cm-3 over exposure times of 100 s. In the environmental chambers, precursors were oxidized using OH Concentrations ranging from 2×106 to 2×107 molec cm-3 over exposure times of several hours. The OH Concentration in the chamber experiments is close to that found in the atmosphere, but the integrated OH exposure in the flow reactor can simulate atmospheric exposure times of multiple days compared to chamber exposure times of only a day or so. A linear correlation analysis of the mass spectra (m=0.91–0.92, r2=0.93–0.94) and carbon oxidation state (m=1.1, r2=0.58) of SOA produced in the flow reactor and environmental chambers for OH exposures of approximately 1011 molec cm-3 s suggests that the composition of SOA produced in the flow reactor and chambers is the same within experimental accuracy as measured with an aerosol mass spectrometer. This similarity in turn suggests that both in the flow reactor and more » in chambers, SOA chemical composition at low OH exposure is governed primarily by gas-phase OH oxidation of the precursors, rather than heterogeneous oxidation of the condensed particles. In general, SOA yields measured in the flow reactor are lower than measured in chambers for the range of equivalent OH exposures that can be measured in both the flow reactor and chambers. The influence of sulfate seed particles on isoprene SOA yield measurements was examined in the flow reactor. The studies show that seed particles increase the yield of SOA produced in flow reactors by a factor of 3 to 5 and may also account in part for higher SOA yields obtained in the chambers, where seed particles are routinely used. « less
