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https://www.readbyqxmd.com/read/28650057/enhanced-catalytic-activity-and-near-room-temperature-gas-sensing-properties-of-sno2-nanoclusters-mesoporous-sn-iv-organophosphonate-composite
#1
Suchibrata Borah, Bagmita Bhattacharyya, Jumi Deka, Aditya Borah, Anuchaya Devi, Dhanapati Deka, Shashank Mishra, Kalyan Raidongia, Nayanmoni Gogoi
A simple, facile and one-pot route for preparing SnO2 nanoclusters embedded on a mesoporous Sn(iv) organophosphonate (MSnP) framework is described. Reaction of SnCl4·5H2O with a flexible tris-phosphonic acid, mesityl-1,3,5-tris(methylenephosphonic acid), in the presence of a surfactant under hydrothermal conditions produced the desired nanocomposite, SnO2@MSnP. Analytical, spectroscopic and microscopic studies establish that SnO2@MSnP composite is comprised of SnO2 nanoparticles of an average size of 5 nm evenly and abundantly dispersed over the MSnP framework...
June 26, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28647251/pet-modified-red-mud-as-catalysts-for-oxidative-desulfurization-reactions
#2
Nayara T do Prado, Ana P Heitmann, Herman S Mansur, Alexandra A Mansur, Luiz C A Oliveira, Cinthia S de Castro
This work describes the synthesis of catalysts based on red mud/polyethylene terephthalate (PET) composites and their subsequent heat treatment under N2 atmosphere. The materials were characterized by scanning electron microscopy (SEM), temperature programmed reduction (TPR), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric (TG) analysis and N2 adsorption/desorption. The catalysts were evaluated in the oxidative desulfurization reaction of dibenzothiophene (DBT) in a biphasic system...
July 2017: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/28647220/investigation-of-zinc-recovery-by-hydrogen-reduction-assisted-pyrolysis-of-alkaline-and-zinc-carbon-battery-waste
#3
Burçak Ebin, Martina Petranikova, Britt-Marie Steenari, Christian Ekberg
Zinc (Zn) recovery from alkaline and zinc-carbon (Zn-C) battery waste were studied by a laboratory scale pyrolysis process at a reaction temperature of 950°C for 15-60min residence time using 5%H2(g)-N2(g) mixture at 1.0L/min gas flow rate. The effect of different cooling rates on the properties of pyrolysis residue, manganese oxide particles, were also investigated. Morphological and structural characterization of the produced Zn particles were performed. The battery black mass was characterized with respect to the properties and chemical composition of the waste battery particles...
June 21, 2017: Waste Management
https://www.readbyqxmd.com/read/28646776/characterizing-the-pahs-in-surface-waters-and-snow-in-the-athabasca-region-implications-for-identifying-hydrological-pathways-of-atmospheric-deposition
#4
S J Birks, S Cho, E Taylor, Y Yi, J J Gibson
The composition of polycyclic aromatic hydrocarbons present in snow and surface waters in the Athabasca Oil Sands Region (AOSR) was characterized in order to identify major contributors to the organics detected in rivers and lakes in the region. PAH concentrations, measured by three monitoring programs in 2011, were used to compare the PAH compositions of snow and surface waters across the AOSR. The 2011 dataset includes total (dissolved+particulate) concentrations of thirty-four parent and alkylated PAH compounds in 105 snow, 272 river, and 3 lake samples...
June 21, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28646737/pollution-characteristics-and-source-identification-of-trace-metals-in-riparian-soils-of-miyun-reservoir-china
#5
Lanfang Han, Bo Gao, Jin Lu, Yang Zhou, Dongyu Xu, Li Gao, Ke Sun
The South-to-North Water Diversion Project, one of China's largest water diversion projects, has aroused widespread concerns about its potential ecological impacts, especially the potential release of trace metals from shoreline soils into Miyun Reservoir (MYR). Here, riparian soil samples from three elevations and four types of land use were collected. Soil particle size distributions, contents and chemical fractionations of trace metals and lead (Pb) isotopic compositions were analyzed. Results showed that soil texture was basically similar in four types of land use, being mainly composed of sand, with minor portions of clay and silt, while recreational land contained more abundant chromium (Cr), copper (Cu), zinc (Zn) and cadmium (Cd), suggesting a possible anthropogenic source for this soil pollution...
June 21, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28640598/structural-and-light-absorption-characteristics-of-complex-water-insoluble-organic-mixtures-in-urban-submicron-aerosols
#6
Qingcai Chen, Fumikazu Ikemori, Yuua Nakamura, Petr Vodicka, Kimitaka Kawamura, Michihiro Mochida
Submicrometer aerosols in the urban atmosphere of Nagoya, Japan, were collected in late winter and early spring, and the water-insoluble organic matter (WISOM) in the samples were fractionated into six subfractions based on their polarities by using solvent and normal-phase solid-phase extractions: non-polar (F1), low-polar (F2 and F3), and medium-polar (F4, F5, and F6) fractions. The overall structural characteristics of these subfractions were then analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and high-resolution aerosol mass spectrometry...
June 22, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28640319/observational-constraints-on-particle-acidity-using-measurements-and-modelling-of-particles-and-gases
#7
J G Murphy, P K Gregoire, A G Tevlin, G R Wentworth, R A Ellis, M Z Markovic, T C VandenBoer
In many parts of the world, the implementation of air quality regulations has led to significant decreases in SO2 emissions with minimal impact on NH3 emissions. In Canada and the United States, the molar ratio of NH3 : SO2 emissions has increased dramatically between 1990 and 2014. In many regions of North America, this will lead the molar ratio of NHx : SO4, where NHx is the sum of particle phase NH4(+) and gas phase NH3, and SO4 is the sum of particle phase HSO4(-) and SO4(2-), to exceed 2. A thermodynamic model (E-AIM model II) is used to investigate the sensitivity of particle pH, and the gas-particle partitioning of NHx and inorganic nitrate, to the atmospheric NHx : SO4 ratio...
June 22, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28638074/geochemical-constraints-on-the-hadean-environment-from-mineral-fingerprints-of-prokaryotes
#8
Alexey A Novoselov, Dailto Silva, Jerusa Schneider, Ximena Celeste Abrevaya, Michael S Chaffin, Paloma Serrano, Margareth Sugano Navarro, Maria Josiane Conti, Carlos Roberto de Souza Filho
The environmental conditions on the Earth before 4 billion years ago are highly uncertain, largely because of the lack of a substantial rock record from this period. During this time interval, known as the Hadean, the young planet transformed from an uninhabited world to the one capable of supporting, and inhabited by the first living cells. These cells formed in a fluid environment they could not at first control, with homeostatic mechanisms developing only later. It is therefore possible that present-day organisms retain some record of the primordial fluid in which the first cells formed...
June 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28635552/temporal-variation-of-fine-and-coarse-particulate-matter-sources-in-jeddah-saudi-arabia
#9
Chris C Lim, George D Thurston, Magdy Shamy, Mansour Alghamdi, Mamdouh Khoder, Abdullah M Mohorjy, Abdulrahman K Alkhalaf, Jason Brocato, Lung Chi Chen, Max Costa
This study provides the first comprehensive analysis of the seasonal variations and weekday/weekend differences in fine (PM2.5) and coarse (PM2.5-10) particulate matter mass concentrations, elemental constituents, and potential source origins in Jeddah, Saudi Arabia. Air quality samples were collected over one year, from June 2011 to May 2012 at a frequency of three times per week, and analyzed. The average mass concentrations of PM2.5 (21.9 μg/m(3)) and PM10 (107.8 μg/m(3)) during the sampling period exceeded the recommended annual average levels by the World Health Organization (WHO) for PM2...
June 21, 2017: Journal of the Air & Waste Management Association
https://www.readbyqxmd.com/read/28630495/the-solution-plasma-process-for-heteroatom-carbon-nanosheets-the-role-of-precursors
#10
Koangyong Hyun, Nagahiro Saito
The solution plasma process (SPP), known as non-equilibrium cold plasma at atmospheric pressure and room temperature, was used to investigate the synthesis of nitrogen-carbon nasnosheets (NCNs). To verify the effect of elementary composition and structure of N-methyl-2-pyrrolidone (NMP), various precursors were used in the SPP to synthesize NCNs via the bottom-up synthesis method for the first time. The NCNs were analyzed by transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28630346/the-role-of-jet-and-film-drops-in-controlling-the-mixing-state-of-submicron-sea-spray-aerosol-particles
#11
Xiaofei Wang, Grant B Deane, Kathryn A Moore, Olivia S Ryder, M Dale Stokes, Charlotte M Beall, Douglas B Collins, Mitchell V Santander, Susannah M Burrows, Camille M Sultana, Kimberly A Prather
The oceans represent a significant global source of atmospheric aerosols. Sea spray aerosol (SSA) particles comprise sea salts and organic species in varying proportions. In addition to size, the overall composition of SSA particles determines how effectively they can form cloud droplets and ice crystals. Thus, understanding the factors controlling SSA composition is critical to predicting aerosol impacts on clouds and climate. It is often assumed that submicrometer SSAs are mainly formed by film drops produced from bursting bubble-cap films, which become enriched with hydrophobic organic species contained within the sea surface microlayer...
June 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28628991/bacterial-community-composition-in-rainwater-associated-with-synoptic-weather-in-an-area-downwind-of-the-asian-continent
#12
Wei Hu, Kotaro Murata, Yuka Horikawa, Ayumi Naganuma, Daizhou Zhang
Bacteria are abundant in atmospheric waters and can be disseminated by precipitation to the surface of the Earth, potentially influencing ecosystems, public health and climate. However, data on bacterial communities in rainwater, especially on the association with weather, are very limited. In this study, rainwater was collected at the coastal city Kumamoto, southwestern Japan, in 2015. The bacterial communities in fourteen samples were identified using 16S rRNA sequencing and compared according to the rain types at the synoptic scale, i...
June 13, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28628305/variation-in-methane-emission-rates-from-well-pads-in-four-oil-and-gas-basins-with-contrasting-production-volumes-and-compositions
#13
Anna M Robertson, Rachel Edie, Dustin Snare, Jeffrey Soltis, Robert Alexander Field, Matthew D Burkhart, Clay S Bell, Daniel Zimmerle, Shane M Murphy
Atmospheric methane emissions from active natural gas production sites in normal operation were quantified using an inverse Gaussian method (EPA's OTM 33a) in four major U.S. basins/plays: Upper Green River (UGR, Wyoming), Denver-Julesburg (DJ, Colorado), Uintah (Utah), and Fayetteville (FV, Arkansas). In DJ, Uintah, and FV, 72 - 83% of total measured emissions were from 20% of the well pads, while in UGR the highest 20% of emitting well pads only contributed 54% of total emissions. The total mass of methane emitted as a percent of gross methane produced, termed throughput-normalized methane average (TNMA) and determined by bootstrapping measurements from each basin, varied widely between basins and was (95% CI): 0...
June 19, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28621942/hygroscopicity-of-organic-compounds-as-a-function-of-carbon-chain-length-carboxyl-hydroperoxy-and-carbonyl-functional-groups
#14
Sarah Suda Petters, Demetrios Pagonis, Megan Suzanne Claflin, Ezra J T Levin, Markus D Petters, Paul J Ziemann, Sonia M Kreidenweis
The albedo and microphysical properties of clouds are controlled in part by the hygroscopicity of particles serving as cloud condensation nuclei (CCN). Hygroscopicity of complex organic mixtures in the atmosphere varies widely and remains challenging to predict. Here we present new measurements characterizing the CCN activity of pure compounds in which carbon chain length and the number of hydroperoxy, carboxyl, and carbonyl functional groups were systematically varied to establish the contributions of these groups to organic aerosol apparent hygroscopicity...
June 16, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28616633/xeromorphic-traits-help-to-maintain-photosynthesis-in-the-perhumid-climate-of-a-taiwanese-cloud-forest
#15
Shyam Pariyar, Shih-Chieh Chang, Daniel Zinsmeister, Haiyang Zhou, David A Grantz, Mauricio Hunsche, Juergen Burkhardt
Previous flux measurements in the perhumid cloud forest of northeastern Taiwan have shown efficient photosynthesis of the endemic tree species Chamaecyparis obtusa var. formosana even under foggy conditions in which leaf surface moisture would be expected. We hypothesized this to be the result of 'xeromorphic' traits of the Chamaecyparis leaves (hydrophobicity, stomatal crypts, stomatal clustering), which could prevent coverage of stomata by precipitation, fog, and condensation, thereby maintaining CO2 uptake...
June 14, 2017: Oecologia
https://www.readbyqxmd.com/read/28612491/graphene-group-5-transition-metal-dichalcogenides-composites-for-electrochemical-applications
#16
Martin Pumera
In comparison to the extensive research and great success attained by Group 6 TMDs as hydrogen evolution reaction (HER) electrocatalysts, there is limited research focused on metallic Group 5 TMDs for use as electrocatalysts towards hydrogen evolution reaction. Density functional theory calculations have pointed out that Group 5 TMDs are highly favorable for HER, especially vanadium disulfides. In this work, the nanocomposites of graphene and Group 5 TMDs were synthesized by thermal exfoliation of graphene oxide/TMD precursors in H2S atmosphere or in H2 atmosphere as a control...
June 14, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28609736/effects-of-continental-anthropogenic-sources-on-organic-aerosols-in-the-coastal-atmosphere-of-east-china
#17
Dongjie Shang, Min Hu, Qingfeng Guo, Qi Zou, Jing Zheng, Song Guo
Although organic compounds in marine atmospheric aerosols have significant effects on climate and marine ecosystems, they have rarely been studied, especially in the coastal regions of East China. To assess the origins of the organic aerosols in the East China coastal atmosphere, PM2.5 samples were collected from the atmospheres of the Yellow Sea, the East China Sea, and Changdao Island during the CAPTAIN (Campaign of Air PolluTion At INshore Areas of Eastern China) field campaign in the spring of 2011. The marine atmospheric aerosol samples that were collected were grouped based on the backward trajectories of their air masses...
June 10, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28605873/associations-of-urban-environmental-pollution-with-health-related-physiological-traits-in-a-free-living-bird-species
#18
Petra Bauerová, Jitka Vinklerová, Jakub Hraníček, Vojtěch Čorba, Libor Vojtek, Jana Svobodová, Michal Vinkler
Urban environmental pollution results in contamination of the tissues of synanthropic organisms by toxic trace elements with potential impacts on human health. Passerine birds may serve as convenient indicators of such contamination. In this study we investigated the effect of blood and plumage contamination with heavy metals (lead Pb, cadmium Cd, copper Cu, chromium Cr) and arsenic metalloid (As) on condition, health and ornamental colour in free-living great tit (Parus major) males from 13 cities across the Czech Republic (EU), mist netted during the early breading season (April-May)...
June 8, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28605583/multiple-sulfur-isotope-constraints-on-sources-and-formation-processes-of-sulfate-in-beijing-pm2-5-aerosol
#19
Xiaokun Han, Qingjun Guo, Harald Strauss, Cong-Qiang Liu, Jian Hu, Zhaobing Guo, Rongfei Wei, Marc Peters, Liyan Tian, Jing Kong
Recently air pollution is seriously threatening the health of millions of people in China. Multiple sulfur isotopic compositions of sulfate in PM2.5 samples collected in Beijing are used to better constraining potential sources and formation processes of sulfate aerosol. Here we found the Δ33S values of sulfate in PM2.5 show a pronounced seasonality with positive values in spring, summer and autumn and negative values in winter. Positive Δ33S anomalies are interpreted to result from SO2 photolysis with self-shielding, and may reflect air mass transport between the troposphere and the stratosphere...
June 12, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28605152/in-situ-industrial-bimetallic-catalyst-characterisation-using-scanning-transmission-electron-microscopy-and-x-ray-absorption-spectroscopy-at-one-atmosphere-and-elevated-temperature
#20
Eric Prestat, Matthew Kulzick, Paul Dietrich, Matt Smith, Eu Pin Tien, Grace Burke, Sarah Jane Haigh, Nestor Zaluzec
We have developed a new experimental platform for in situ scanning transmission electron microscope (STEM) energy dispersive X-ray spectroscopy (EDS) which allows real time, nanoscale, elemental and structural changes to be studied at elevated temperature (up to 1000°C) and pressure (up to 1 atm). Here we demonstrate the first application of this approach to understand complex structural changes occurring during reduction of a bimetallic catalyst, PdCu supported on TiO2, synthesized by wet impregnation. We reveal a heterogeneous evolution of nanoparticle size, particle distribution and composition with large differences in reduction behavior for the two metals...
June 12, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
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