The application of distributed fiber optic strain and temperature measurement can be utilized to address a multitude of measurement tasks across a diverse range of fields, particularly in the context of structural health monitoring in the domains of building construction, civil engineering, and special foundation engineering. However, a comprehensive understanding of the influences on the measurement method and the sensors is essential to prevent misinterpretations or measurement deviations. In this context, this study investigated the effects of moisture exposure, including various salt solutions and a high pH value, on a distributed strain measurement using Rayleigh backscattering.
View Article and Find Full Text PDFThe elimination of Bisphenol A (BPA) from contaminated waters is an urgent challenge. This contribution focuses on BPA degradation by homogeneous Fenton reagent based on reactive ()OH radicals. Pronounced sub-stoichiometric amounts of H(2)O(2) oxidant were used to simulate economically viable processes and operation under not fully controlled conditions, as for example in in situ groundwater remediation.
View Article and Find Full Text PDFHomogeneous Fenton reaction (H(2)O(2)/Fe(2+) system) using significantly substoichiometric concentrations of H(2)O(2) oxidant to oxidize phenol was characterized focusing on the formation of stable aromatic intermediates. Beyond the most abundant benzenediols, the pattern of aromatic intermediates was chiefly characterized by hydroxylated biphenyls and diphenyl ethers with different degrees of hydroxylation. Hydroxylated dibenzofurans (DBF), p,p'-dioxins, as well as highly condensed aromatic intermediates including polyols of polycyclic aromatic hydrocarbons (PAHs), could also be detected, but in lower concentrations.
View Article and Find Full Text PDFJ Microw Power Electromagn Energy
March 2009
Selective dielectric heating using the influence of a coupling medium such as water can lead to the formation of combined temperature-mass transport pulses moving through a packed bed. Depending on the dielectric and sorption properties of the material, these so-called thermo-chromatographic pulses (TCP) can cause large temperature differences between the starting temperature and the peak temperature in the pulse. The impregnation of porous substances with various salts was shown to be a simple method for improving material properties leading to the formation of stable TCP.
View Article and Find Full Text PDFHomogeneous catalytic Fenton oxidation proved to be very efficient in the degradation of high concentrations (3.9 mM) of 2-chlorophenol (2-CP) in aqueous matrices. When using [H(2)O(2)](0)/[2-CP](0) substoichiometric molar ratios of 4 and 16, the detected aromatic intermediates included mainly chlorinated benzenediols, with the virtual absence of condensation products of higher molecular weight.
View Article and Find Full Text PDFThe effect of dissolved humic acid (HA) on two types of hydrolysis reactions was investigated: (I) dehydrochlorination of gamma-hexachlorocyclohexane (HCH) and 1,1,2,2-tetrachloroethane (TeCA) as a reaction involving hydroxide ions (OH(-)) and (II) hydrolysis of 1-octyl acetate (OA) which is catalyzed by H(+) at the applied pH value (pH 4.5). The rate of TeCA hydrolysis was not affected by addition of 2 g l(-1) of HA at pH 10 (k' = 0.
View Article and Find Full Text PDFThe effect of sorption to dissolved humic acids (HAs) on the chlorination of PAHs in aqueous solution was studied. The addition of HA accelerated the chlorination of fluoranthene and naphthalene in hypochlorite solutions at pH 5, the stronger effect being observed for fluoranthene that is sorbed to a higher extent than naphthalene. Sorption coefficients (K(DOC)) of the analytes were determined by solid-phase microextraction (SPME).
View Article and Find Full Text PDFControl of hazardous organic micropollutants is a challenging water quality issue. Dissolved humic organic matter (DOM) isolated from oxyhumolite coal mined in Bohemia was investigated as a complexation agent to remove polycyclic aromatic hydrocarbons (PAHs) and functionalized phenols from water by a two-stage process involving complexation and flocculation. After the formation of humic-contaminant complexes, ferric salts were added resulting in the precipitation and flocculation of the DOM and the associated pollutants.
View Article and Find Full Text PDFHumic acid (HA) isolated from highly polluted sediment from the Ravenna Lagoon (Italy) was subjected to pyrolysis/tetramethylammonium hydroxide (TMAH)-induced thermochemolysis to reveal the impact of industrial activities on humification. Special effort was made to distinguish between analytes originating from the polymeric humic organic matter network along with sequestered compounds (which cannot be released by solvent extraction), and the solvent-extractable lipid fraction sorbed onto the organic matrix. Exhaustive solvent extraction of the isolated HA proved mandatory to avoid biased results when identifying the origin of the pyrolyzates of untreated samples.
View Article and Find Full Text PDFA new approach using sequential pressurized liquid extraction described recently [J. Poerschmann, R. Carlson, J.
View Article and Find Full Text PDF