Ngo P.-T.,French National Center for Scientific Research |
Ngo P.-T.,Institute of Environmental Technology |
Rumpel C.,French National Center for Scientific Research |
Ngo Q.-A.,Institute of Chemistry |
And 5 more authors.
Bioresource Technology | Year: 2013
This study characterized the carbon and phosphorus composition of buffalo manure, its compost and vermicompost and investigated if presence of bamboo biochar has an effect on their chemical and biological reactivity. The four substrates were characterized for chemical and biochemical composition and P forms. The biological stability of the four substrates and their mixtures were determined during an incubation experiment. Their chemical reactivity was analyzed after acid dichromate oxidation.Biological reactivity of these substrates was related to their soluble organic matter content, which decreased in the order buffalo manure. >. compost. >. vermicompost. Phosphorus was labile in all organic substrates and composting transformed organic P into plant available P. The presence of biochar led to a protection of organic matter against chemical oxidation and changed their susceptibility to biological degradation, suggesting that biochar could increase the carbon sequestration potential of compost, vermicompost and manure, when applied in mixture. © 2013 Elsevier Ltd.
Reli M.,Institute of Environmental Technology |
Sihor M.,Institute of Environmental Technology |
Praus P.,Institute of Environmental Technology |
Svoboda L.,Institute of Environmental Technology |
And 8 more authors.
International Journal of Hydrogen Energy | Year: 2015
ZnO photocatalysts were prepared by thermal annealing of zinc acetate, by precipitation reaction of zinc acetate with sodium hydroxide followed by thermal annealing and by precipitation reaction of zinc acetate with sodium hydroxide in the presence of UV irradiation followed by thermal annealing. The prepared nanoparticles were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), UV-Vis diffuse reflectance (UV-Vis DRS) and photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM) and N2 physisorption measurements. The photocatalytic performance of these materials was investigated for H2 evolution using aqueous ammonia media under 254 nm UV light. The H2 evolution was compared with TiO2 Evonik P25. Beside H2 photocatalytic generation, H2 photochemical generation was also observed. The different used synthetic procedure leading to the formation of different defects (oxygen vacancies (VO) and oxygen excess defects (Oi/OZn)) in the ZnO lattice were factors influencing photocatalytic production of hydrogen. Oxygen vacancy (VO) was recognized as defect significantly decreasing photocatalyst activity. The highest yields of hydrogen were observed in ZnO prepared by thermal annealing of zinc acetate in air. This photocatalyst possesses the lowest concentration of oxygen vacancies causing efficient trapping of electrons. Consequently higher number of electrons in conduction band was available for photocatalytic reaction. Copyright © 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Ngo P.-T.,French National Institute for Agricultural Research |
Ngo P.-T.,Institute of Environmental Technology |
Rumpel C.,French National Institute for Agricultural Research |
Thu T.D.,French National Institute for Agricultural Research |
And 4 more authors.
Carbon Management | Year: 2014
Background: Exogenous organic matter may be valuable amendments for degraded tropical soil in Northern Vietnam. Their effect on carbon storage and composition need to be evaluated.Method: The study investigates soil from mesocosms cultivated with maize and amended with four different kinds of amendments: only mineral fertilizers (control), buffalo manure, compost or vermicompost as well as biochar.Results: All organic amendments showed a positive effect on soil carbon storage and significantly influenced soil organic matter quality. The presence of biochar increased lignin-derived compounds abundance as well as both plant and microbial sugar content of soil amended with vermicompost but had no effect in the case of control soil.Conclusion: Synergistic effects between plants and different organic amendments influence carbon storage and soil organic matter composition. © 2014 Taylor & Francis.
Le Truong G.,Institute of Chemistry |
Nguyen N.T.,Institute of Chemistry |
Nguyen Q.T.,Institute of Environmental Technology |
De Laat J.,University of Poitiers |
Dao H.Y.,Institute of Chemistry
Journal of Advanced Oxidation Technologies | Year: 2014
This study aims to demonstrate the effects of pH and of inorganic anions on the photoreduction of Fe(III). Effective quantum yields for the production of •OH radicals from iron(III) hydroxo species in pechlorate medium and in the present of chloride and sulfate anions were determined in the pH range 1-3. Experiments were carried out in batch at 25°C with a low-pressure mercury vapor lamp emitted at 253.7 nm. The method was based on measuring the pseudo-first-order rate constant of the photoreduction of Fe(III)-complexes in which tert-butanol scavenged the •OH at an identical rate. The results showed that the apparent quantum yield of photoreduction of Fe(III) increased when the pH increases, the values passed from 0.063 at pH 1 to 0.1 at pH 3 ([Fe(III)]0 = 1 mM and 3 mM). The effects of Cl- or SO4 2- on the photoreduction of Fe(III) depended on pH and on ion concentrations. The apparent quantum yield values increased in the present of anion Cl-, whereas those values decreased in the present of anion SO4 2-. For the Photo Fenton system, the effects of Cl - or SO4 2- were found to depend on pH, on the concentrations of the inorganic anions and to decrease the rate of decomposition of H2O2. © 2014 Science & Technology Network, Inc.
Jiang S.,Gwangju Institute of Science and Technology |
Ho C.T.,Gwangju Institute of Science and Technology |
Ho C.T.,Institute of Environmental Technology |
Lee J.-H.,Pacific Northwest National Laboratory |
And 3 more authors.
Chemosphere | Year: 2012
Shewanella putrefaciens 200, resistant to high concentration of Hg(II), was selected for co-removal of mercury and selenium from aqueous medium. Biogenic Hg(0) reduced from Hg(II) by S. putrefaciens 200 was captured into extracellular amorphous selenium nanospheres, resulting in the formation of stable HgSe nanoparticles. This bacterial reduction could be a new strategy for mercury removal from aquatic environments without secondary pollution of mercury methylation or Hg(0) volatilization. © 2012 Elsevier Ltd.
Kubonova L.,Institute of Environmental Technology |
Fridrichova D.,Institute of Environmental Technology |
Fridrichova D.,Energy Units for Utilization of Non Traditional Energy Sources |
Peikertova P.,Institute of Environmental Technology |
And 7 more authors.
NANOCON 2015 - 7th International Conference on Nanomaterials - Research and Application, Conference Proceedings | Year: 2015
Three different ordered mesoporous silica materials, such as MCM-41, Al containing MCM-41 (mass ratio Si/Al = 10) and SBA-15, were prepared. In a next step, cobalt (5-8 wt%) as an active metal for redox reactions, was introduced by the impregnation. The prepared catalysts were characterized by AAS, EDX, N2 physisorption, XRD, DR UV-Vis spectroscopy, Raman spectroscopy, TPR-H2 and their catalytic properties were evaluated for N2O decomposition and reduction. The catalysts showed poor activity in N2O decomposition while the use of reducing agent (carbon monoxide) was beneficial for their catalytic activities. The lowest catalytic activity showed Co/Al-MCM indicating that the aggregated CoxOy species present in this catalyst were inactive and not beneficial for the catalytic activity.
Lefebvre J.-P.,CIRAD - Agricultural Research for Development |
Lefebvre J.-P.,Hanoi University of Science |
Mari X.,CIRAD - Agricultural Research for Development |
Do T.P.T.,Institute of Environmental Technology |
Chu T.V.,Institute of Marine Environment and Resources
Proceedings of the Coastal Engineering Conference | Year: 2014
Transparent exopolymer particles (TEP) are widely recognized to promote sediment aggregation in eutrophic environments. Flocculation in presence of TEP of various suspended sediment concentrations of material sampled on the bank of the Cam River was quantified at the laboratory for turbulence level consistent with slack water and mid ebb conditions measured in the Cam River estuary during dry season of 2009. Stickiness and concentrations of TEP were let to naturally fluctuate by incubation (aging in the dark) for up to nine days. We found that the impact of turbulence on overall buoyancy of TEP-governed aggregation was always opposite between slack water and mid ebb conditions for any duration of incubation; always negative for slack water conditions but for 126 hours of incubation and significantly negative for mid ebb conditions but for 126 hours of incubation. Suspended sediment concentration (SSC) consistently limited aggregates buoyancy, negative or positive. We propose a conceptual model that relates measured and inferred parameters to observed hydrosedimentary processes.
Fujikawa Y.,Kyoto University |
Hung D.,Institute of Environmental Technology |
Sugahara M.,Osaka Sangyo University |
Iwasaki H.,Osaka Sangyo University |
And 2 more authors.
Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment | Year: 2012
We conducted the pilot test of biological filtration in Hanoi, Vietnam. Arsenite [As(III)] is a chemical species diffcult to remove if not converted to arsenate [As(V)], and 90% of arsenic (As) in the well water there was As(III). However, our system was able to treat As with no-preoxidation step by the average removal exceeding 80%. © 2012 Taylor & Francis Group.
Thang P.Q.,Osaka Prefecture University |
Thang P.Q.,Institute of Environmental Technology |
Taniguchi T.,Osaka Prefecture University |
Nabeshima Y.,Osaka Prefecture University |
And 3 more authors.
Air Quality, Atmosphere and Health | Year: 2014
This study reported the distribution of polycyclic aromatic hydrocarbons (PAHs) concentrations simultaneously obtained in gas/rain/particle in rain event from 2010 to 2012 in Osaka, Japan. A sampling method for rain and the materials of a rain collector were also surveyed. Benzene and a glass bottle were used to prevent the decrease of PAHs in rainwater. The average concentration of Σ9PAHs in rainwater ranged between 17.49 and 646.52 ng dm-3. The mean ratio of these Σ9PAHs in gas versus particles was 77.9 and 68.3 % during rain and no rain, respectively. During rain, the PAHs in particles were scavenged by rain and were incorporated via washout by collision with each other. Therefore, the ratio of PAHs in rainwater was similar to that in particles. The low molecular weight LMW-PAHs from gas were recognized as being dissolved in rain but did not affect the ratio of PAHs in rain. Four rings PAH were dominant in gas/rain/particles. The seasonal variation of Σ9PAHs in rainwater was reported and discussed, and the PAHs levels during the winter and spring were higher compared with that of summer and autumn. Furthermore, the sampling method of PAHs in snow is also developed. © 2014 Springer Science+Business Media Dordrecht.