Search results for "Earth and Related Environmental Sciences"
showing 10 items of 6573 documents
Influence of HCl pretreatment and organo-mineral complexes on laser diffraction measurement of loess–paleosol-sequences
2016
Abstract The influence of different sample pretreatment methods on grain size distributions in particle size analysis has been subject to controversial discussions. Standard sample preparation typically comprises the disaggregation of aggregated and agglomerated particles into single primary particles, i.e., the organic binding material is oxidized by hydrogen peroxide (H2O2) and the contained carbonates are dissolved by hydrochloric acid (HCl). The aim of this study is to evaluate the effects of HCl treatment on grain size analyses of Late Pleistocene and Holocene loess–paleosol-sequences investigated by a Beckman Coulter LS 13320 laser particle analyzer. For this purpose, samples from two…
A study of weathered coal spectroscopic properties
2017
Abstract Current coal industry causes significant environmental pollution and the most air pollution deaths in the world, making the development of new eco-friendly applications one of the top priorities. Coal contains up to 50 % humic substances (HS), the majority of which is humic acid (HA). HA is well known for its beneficial properties and thus compounds extracted from coal can be used to develop new applications. To address this issue, we assessed structural composition of coal HS by measuring their spectroscopic properties. As the result, obtained spectra can be used to identify information about the molecules and thus allowing describing the composition of HS. The purpose of this stu…
Low-Molecular-Weight Organic Acid Complexation Affects Antimony(III) Adsorption by Granular Ferric Hydroxide.
2019
Antimony(III) mobility in natural aquatic environments is generally enhanced by dissolved organic matter. Tartaric acid is often used to form complexes with and stabilize dissolved Sb(III) in adsorption studies. However, competition between such low-molecular-weight organic acid complexation and adsorption of Sb(III) has received little attention, which prompted us to measure Sb(III) adsorption by iron oxyhydroxide adsorbents commonly used in water treatment plants. Sb K-edge X-ray absorption fine structure (EXAFS) spectra gave Sb–O and Sb–Fe distances and coordinations compatible with a bidentate binuclear inner-sphere complex with trigonal Sb(O,OH)3 polyhedra sharing corners with Fe(O,OH)…
Development of a Matrix-Matched Sphalerite Reference Material (MUL-ZnS-1) for Calibration of In Situ Trace Element Measurements by Laser Ablation-Ind…
2016
Sphalerite (ZnS) is an abundant ore mineral and an important carrier of elements such as Ge, Ga and In used in high-technology applications. In situ measurements of trace elements in natural sphalerite samples using LA-ICP-MS are hampered by a lack of homogenous matrix-matched sulfide reference materials available for calibration. The preparation of the MUL-ZnS1 calibration material containing the trace elements V, Cr, Mn, Co, Ni, Cu, Ga, Ge, As, Se, Mo, Ag, Cd, In, Sn, Sb, Tl and Pb besides Zn, Fe and S is reported. Commercially available ZnS, FeS, CdS products were used as the major components, whereas the trace elements were added by doping with single-element ICP-MS standard solutions a…
A detailed MSn study for the molecular identification of a dimer formed from oxidation of pinene
2016
Abstract Dimeric products formed in the oxidation of α- and β-pinene have been frequently observed in laboratory and field studies of biogenic SOA formation. While their existence is undoubted, their exact chemical structures remain unclear. This study uses a combined two step approach aiming on the molecular identification of the most important of the various dimers that have been observed in biogenic secondary organic aerosol formation, a dimer with the molecular weight 358 g mol−1. The first step is the application of a functional group derivatization technique (esterification) to quantify the number of carboxylic acid groups in the target molecule. Based on the detailed interpretation o…
The effect of iron on the biodegradation of natural dissolved organic matter
2016
Iron (Fe) may alter the biodegradation of dissolved organic matter (DOM), by interacting with (DOM), phosphorus (P) and microbes. We isolated DOM and a bacterial community from boreal lake water and examined bacterial growth on DOM in laboratory experiments. Fe was introduced either together with DOM (DOM-Fe) or into bacterial suspension, which led to the formation of insoluble Fe-precipitates on bacterial surfaces (Fe coating). In the latter case, the density of planktonic bacteria was an order of magnitude lower than that in the corresponding treatment without introduced Fe. The association of Fe with DOM decreased bacterial growth, respiration, and growth efficiency compared with DOM alo…
Suppression of new particle formation from monoterpene oxidation by NO<sub>x</sub>
2014
Abstract. The impact of nitrogen oxides (NOx = NO + NO2) on new particle formation (NPF) and on photochemical ozone production from real plant volatile organic compound (BVOC) emissions was studied in a laboratory setup. At high NOx conditions ([BVOC] / [NOx] < 7, [NOx] > 23 ppb) new particle formation was suppressed. Instead, photochemical ozone formation was observed resulting in higher hydroxyl radical (OH) and lower nitrogen monoxide (NO) concentrations. When [NO] was reduced back to levels below 1 ppb by OH reactions, NPF was observed. Adding high amounts of NOx caused NPF to be slowed by orders of magnitude compared to analogous experiments at low NOx conditions ([NOx] ~300 ppt)…
In situ submicron organic aerosol characterization at a boreal forest research station during HUMPPA-COPEC 2010 using soft and hard ionization mass s…
2013
The chemical composition of submicron aerosol during the comprehensive field campaign HUMPPA-COPEC 2010 at Hyytiälä, Finland, is presented. The focus lies on online measurements of organic acids, which were achieved by using atmospheric pressure chemical ionization (APCI) ion trap mass spectrometry (IT-MS). These measurements were accompanied by aerosol mass spectrometry (AMS) measurements and Fourier transform infrared spectroscopy (FTIR) of filter samples, all showing a high degree of correlation. The soft ionization mass spectrometer alternated between gas-phase measurements solely and measuring the sum of gas and particle phase. The AMS measurements of C, H and O elemental composition s…
UHPLC-Orbitrap mass spectrometric characterization of organic aerosol from a central European city (Mainz, Germany) and a Chinese megacity (Beijing)
2018
Abstract Fine urban aerosol particles with aerodynamic equivalent dimeter ≤2.5 μm (PM2.5) were collected in Mainz (a city within the Rhine-Main area, the third largest metropolitan region in Germany) and Beijing (Chinese megacity). A solvent mixture of acetonitrile-water was used to extract the organic aerosol fraction (OA) from the particle samples. The extracts were analyzed by an ultrahigh resolution mass spectrometer (UHRMS) Orbitrap coupled with ultra-high-performance liquid chromatography (UHPLC) both in the negative and positive ion mode. The number of compounds observed in Beijing is a factor of 2–10 higher compared to Mainz. The clear differences on chemical composition of OA in th…
Composition, crystallization conditions and genesis of sulfide-saturated parental melts of olivine-phyric rocks from Kamchatsky Mys (Kamchatka, Russi…
2020
Highlights • Parental melts of sulfide-bearing KM rocks have near primary MORB-like composition. • Crystallization of these S-saturated melts occurred in near-surface conditions. • Extensive fractionation and crustal assimilation are not the causes of S-saturation. • S content in melts can be restored by accounting for daughter sulfide globules. Abstract Sulfide liquids that immiscibly separate from silicate melts in different magmatic processes accumulate chalcophile metals and may represent important sources of the metals in Earth's crust for the formation of ore deposits. Sulfide phases commonly found in some primitive mid-ocean ridge basalts (MORB) may support the occurrence of sulfide …