Search results for "leaching"
showing 10 items of 267 documents
The Relevance of Mineral Mobilization and -Dissolution on the Reservoir Quality of Sandstones in CO2 Storage Sites
2014
Abstract Rotliegend siliciclastic formations are important reservoirs in central Europe. These sediments consist of pristine red coloured and bleached, high porous and permeable sandstones. To evaluate the relevance of distinct fluids and their fluid-rock alteration reactions on such bleaching processes laboratory static batch experiments under reservoir conditions were conducted. Thereby mineralogical, petrophysical and (hydro-, geo-) chemical rock features were investigated by different analytical methods before and after the experiments. The achieved results suggest that during such fluid-rock interactions a complex interplay between mineral detachment and mineral dissolution processes w…
Methods of metal release assessment in soil water at anoxic sites
2006
Department of Geology, Vienna University, Vienna, Austria Metal mobility at contaminated sites can be assessed by soil water investigations or by leaching tests. Leaching tests are usually carried out in open contact with the atmosphere disregarding possible changes of redox conditions. This can affect the original metal speciation and distribution, particularly when anoxic samples are investigated. In this study, the applicability of common leaching tests (the German S4 test (S4), ammonium nitrate extraction (AmmN), and saturation soil extraction (SSE)) is tested for the assessment of zinc release from sulfide-bearing flotation residues of a former ore mine. Results are compared to soil so…
Aspects of soil phenolic matter (SPM): An explorative investigation in agricultural, agroforestry, and wood ecosystems
2014
Abstract This paper assesses the distribution of soil phenolic matter (SPM) in soil environments from a pedological perspective, with particular emphasis on soil horizonation and its involvement in pedogenic processes. The study was conducted on 15 soil profiles (Andosols, Calcisols, Cambisols, Lixisols, Phaeozems, Podzols, Umbrisols) covering five distinct ecosystems. Although the ecosystems were virtually homogeneous in and of themselves, they represented strongly contrasting climates, geolithology and morphology, land use and vegetation cover (intensive agriculture, chestnut grove, alpine pasture, woody reforestations, and natural woods). Three main SPM fractions were categorised: (i) “t…
Analysis of total antioxidant capacity and total phenolic content during ripeting of Sicilian red grapes
2010
Quantitative XPS analysis of leached layers on optical glasses
1993
The corrosion of optical glasses often reduces the utility of uncoated glasses as well as the adhesion of resistive coatings deposited onto corroded glasses. Photoelectron spectroscopy (XPS) was applied to study glass surfaces with respect to their surface corrosion. In particular, leaching by the influence of polish slurries, pure water, air and even residual gases inside a vacuum device was studied in detail. Pure quartz glass and different sodium and barium silicate glasses were broken in ultrahigh vacuum (4 × 10−10 mbar) for the determination of sensitivity factors of the different XPS signals. It was found that a quantitative determination of the surface composition of corroded and lea…
Single Molecule Spectroscopy of Oriented Recombinant Trimeric Light Harvesting Complexes of Higher Plants
2002
The bleaching dynamics of reconstituted single light-harvesting chlorophyll a/b investigated. The complexes containing one histidine6 tag per monomeric subunit were immobilised predominantly in a defined orientation with their symmetry axis perpendicular to a Ni-ion-containing surface allowing for the first time the examination of single LHCIIb in an aqueous environment. Most complexes exhibit photobleaching in one step, indicating coupling between the monomeric subunits leading to an energy transfer between adjacent subunits. Differences in bleaching behaviour between these and previous observations with single LHCIIb are discussed.
The influence of ultrasound on the RuI3-catalyzed oxidation of phenol: Catalyst study and experimental design
2009
Abstract The influence of ultrasound at 24 kHz on the heterogeneous aqueous oxidation of phenol over RuI3 with hydrogen peroxide (H2O2) was studied isothermally at 298 K. Effect of ultrasound irradiation on catalytic properties and performance of RuI3 has been studied in details by means of scanning electron microscopy (SEM), X-ray powder diffraction (XRD), dispersion analyzer and a surface analyzer. Turn over frequency of the catalyst was also calculated. In this work, experimental design methodology was applied to optimize the degradation of phenol in aqueous solution, while minimizing an excessive consumption of chemical reagents. The independent variables considered were the catalyst lo…
Mineral control of arsenic content in thermal waters from volcano-hosted hydrothermal systems: Insights from island of Ischia and Phlegrean Fields (C…
2006
This paper documents arsenic concentrations in 157 groundwater samples from the island of Ischia and the Phlegrean Fields, two of the most active volcano-hosted hydrothermal systems from the Campanian Volcanic Province (Southern Italy), in an attempt to identify the environmental conditions and mineral-solution reactions governing arsenic aqueous cycling. On Ischia and in the Phlegrean Fields, groundwaters range in composition from NaCl brines, which we interpret as the surface discharge of deep reservoir fluids, to shallow-depth circulating fluids, the latter ranging from acid-sulphate steam-heated to hypothermal, cold, bicarbonate groundwaters. Arsenic concentrations range from 1.6 to 690…
Parallel Measurements of in-vivo Skin Autofluorescence Lifetimes and Photobleaching Rates
2015
Experimental methodology for parallel measurements of in-vivo skin autofluorescence (AF) lifetimes and photo-bleaching dynamic has been developed and tested. The AF lifetime decay distributions were periodically collected from fixed tissue area with subsequent detection of the fluorescence intensity decrease dynamic at different time shifts after the pulse excitation. Temporal distributions of skin AF lifetimes and bleaching dynamic were collected and analyzed by means of commercial time-correlated single photon counting system. Details of the equipment and data processing are described as well as some measurement results that confirm the feasibility of the proposed technology.
Photobleaching measurements of pigmented and vascular skin lesions: results of a clinical trial
2011
The autofluorescence photobleaching intensity dynamics of in vivo skin and skin pathologies under continuous 532 nm laser irradiation have been studied. Overall the 141 human skin malformations were investigated by laser induced skin autofluorescence photobleaching analysis. Details of equipment are described along with some measurement results illustrating potentiality of the technology.