Removal of Lead, Copper, Zinc and Cadmium from Water Using Phosphate Rock

Removal of Pb2 ,Cu~(2 ),Zn~(2 )and Cd~(2 )from aqueous solutions by sorption on a natural phosphate rock(FAP)was investigated.The effects of the contact time and initial metal concentration were examined in the batch method.The percentage sorption of heavy metals from solution ranges generally between 50% and 99%.The amount of sorbed metal ions follows the order Cu>Pb>Cd>Zn. Heavy metal immobilization was attributed to both surface complexation of metal ions on the surface of FAP grains and partial dissolution and precipitation of a heavy metal-containing phosphate.The very low desorption ratio of heavy metals further supports the effectiveness of FAP as an alternative and low-cost material to remove toxic Pb~(2 ),Cu~(2 ),Zn~(2 )and Cd~(2 )from polluted waters.     

Characteristics of topographic submesoscale eddies off the Crimea coast from high-resolution satellite optical measurements

Ocean Dynamics - Long-term arrays of satellite optical measurements of Landsat-5,7,8 and Sentinel-2 were used to describe the characteristics of submesoscale eddy (SE) dynamics in different parts...     

Cryptic metasomatic agent measured in situ in Variscan mantle rocks: Melt inclusions in garnet of eclogite,Granulitgebirge, Germany

Garnet of eclogite (formerly termed garnet clinopyroxenite) hosted in lenses of orogenic garnet peridotite from the Granulitgebirge, NW Bohemian Massif, contains unique inclusions of granitic melt, now either glassy or crystallized. Analysed glasses and re-homogenized inclusions are hydrous, peraluminous, and enriched in highly incompatible elements characteristic of the continental crust such as Cs, Li, B, Pb, Rb, Th, and U. The original melt thus represents a pristine, chemically evolved metasomatic agent, which infiltrated the mantle via deep continental subduction during the Variscan orogeny. The bulk chemical composition of the studied eclogites is similar to that of Fe-rich basalt and the enrichment in LILE and U suggest a subduction-related component. All these geochemical features confirm metasomatism. In comparison with many other garnet+clinopyroxene-bearing lenses in peridotites of the Bohemian Massif, the studied samples from Rubinberg and Klatschmühle are more akin to eclogite than pyroxenites, as reflected in high jadeite content in clinopyroxene, relatively low Mg, Cr, and Ni but relatively high Ti. However, trace elements of both bulk rock and individual mineral phases show also important differences making these samples rather unique. Metasomatism involving a melt requiring a trace element pattern very similar to the composition reported here has been suggested for the source region of rocks of the so-called durbachite suite, that is, ultrapotassic melanosyenites, which are found throughout the high-grade Variscan basement. Moreover, the Th, U, Pb, Nb, Ta, and Ti patterns of these newly studied melt inclusions (MI) strongly resemble those observed for peridotite and its enclosed pyroxenite from the T-7 borehole (Staré, České Středhoři Mountains) in N Bohemia. This suggests that a similar kind of crustal-derived melt also occurred here. This study of granitic MI in eclogites from peridotites has provided the first direct characterization of a preserved metasomatic melt, possibly responsible for the metasomatism of several parts of the mantle in the Variscides.     

A single vs. double spike approach to improve the accuracy of Th measurements in small-volume seawater samples

²³⁴Th is a particle-reactive radionuclide widely used to trace biogeochemical oceanic processes occurring over short timescales. During the last few years, small-volume techniques based on the co-precipitation of ²³⁴Th with MnO₂ coupled with beta-counting have been developed as an alternative to large volume gamma-spectrometric techniques. Here a procedure has been developed to enhance quantitative measurement of ²³⁴Th in MnO₂ precipitates. The main objectives were to obtain a purified Th fraction for beta-counting and to determine the chemical recovery of ²³⁴Th using Th spikes and alpha-spectrometry as an alternative to ICP-MS based methods. Two variations of the procedure are presented. In the first “1 spike” method a ²³⁰Th tracer is added to the sample prior to precipitation of MnO₂, and UTEVA® extraction chromatography is used to obtain a NdF₃(Th) purified source that can be used for both beta-counting of ²³⁴Th and alpha-spectrometry of ²³⁰Th. In the “2 spike” method a ²³⁰Th spike is added and the MnO₂(Th) precipitate is directly beta-counted for ²³⁴Th and subsequently spiked with ²²⁸Th or ²²⁹Th prior to UTEVA® purification and alpha-spectrometry. The results confirm the need to process small-volume seawater samples for ²³⁴Th measurement in presence of a yield tracer, and show that both the 1 spike and 2 spike methods allow an accurate and precise determination of ²³⁴Th (relative percent difference, RPD, between expected and mean measured value < 1%; CV between replicate samples < 3%). Our work also suggests that, although the combined analytical uncertainty on total ²³⁴Th measurements accomplished with both versions of the NdF₃ procedure is promising (6% for 2-L samples), the precision of the ²³⁴Th flux estimation will ultimately depend on the degree of disequilibrium between ²³⁴Th and ²³⁸U.     

Evaluation of liquefaction potential in an intermountain Quaternary lacustrine basin (Fucino basin,central Italy)

In this study, we analyse the susceptibility to liquefaction of the Pozzone site, which is located on the northern side of the Fucino lacustrine basin in central Italy. In 1915, this region was struck by a M 7.0 earthquake, which produced widespread coseismic surface effects that were interpreted to be liquefaction-related. However, the interpretation of these phenomena at the Pozzone site is not straightforward. Furthermore, the site is characterized by an abundance of fine-grained sediments, which are not typically found in liquefiable soils. Therefore, in this study, we perform a number of detailed stratigraphic and geotechnical investigations (including continuous-coring borehole, CPTu, SDMT, SPT, and geotechnical laboratory tests) to better interpret these 1915 phenomena and to evaluate the liquefaction potential of a lacustrine environment dominated by fine-grained sedimentation. The upper 18.5 m of the stratigraphic succession comprises fine-grained sediments, including four strata of coarser sediments formed by interbedded layers of sand, silty sand and sandy silt. These strata, which are interpreted to represent the frontal lobes of an alluvial fan system within a lacustrine succession, are highly susceptible to liquefaction. We also find evidence of paleo-liquefaction, dated between 12.1–10.8 and 9.43–9.13 kyrs ago, occurring at depths of 2.1–2.3 m. These data, along with the aforementioned geotechnical analyses, indicate that this site would indeed be liquefiable in a 1915-like earthquake. Although we found a broad agreement among CPTu, DMT and shear wave velocity “simplified procedures” in detecting the liquefaction potential of the Pozzone soil, our results suggest that the use and comparison of different in situ techniques are highly recommended for reliable estimates of the cyclic liquefaction resistance in lacustrine sites characterized by high content of fine-grained soils. In geologic environments similar to the one analysed in this work, where it is difficult to detect liquefiable layers, one can identify sites that are susceptible to liquefaction only by using detailed stratigraphic reconstructions, in situ characterization, and laboratory analyses. This has implications for basic (Level 1) seismic microzonation mapping, which typically relies on the use of empirical evaluations based on geologic maps and pre-existing sub-surface data (i.e., age and type of deposits, prevailing grain size, with particular attention paid to clean sands, and depth of the water table).     

Carbon dioxide photoelectron energy peaks at Mars

The ELectron Spectrometer (ELS) from the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) flown on the Mars Express spacecraft has an 8% energy resolution, combined with the capability to oversample the martian electron distribution. This makes possible the resolution and identification of electrons generated as a result of the He 304 Å ionization of CO₂ at the martian exobase on the dayside of the planet. Ionospheric photoelectrons were observed during almost every pass into the ionosphere and CO₂ photoelectron peaks were identified near the terminator. Atmospherically generated CO₂ photoelectrons are also observed at 10,000 km altitude in the martian tail near the inner magnetospheric boundary. Observations over a wide range of spacecraft orbits showed a consistent presence of photoelectrons at locations along the inner magnetospheric boundary and in the ionosphere, from an altitude of 250 to 10,000 km.     

Plasma intrusion above Mars crustal fields—Mars Express ASPERA-3 observations

Using data of the ASPERA-3 instrument on board the European Mars Express spacecraft we investigate the effect of the martian crustal fields on electrons intruding from the magnetosheath. For the crustal field strength we use published data obtained by the Mars Global Surveyor MAG/ER instrument for a fixed altitude of 400 km. We use statistics on 13 months of 80-100 eV electron observations to show that the electron intrusion altitude determined by a probability measure is approximately linearly dependent on the total field strength at 400 km altitude. We show that on the dayside the mean electron intrusion altitude describes the location of the Magnetic Pile-Up Boundary (MPB) such that we can quantify the effect of the crustal fields on the MPB. On the nightside we quantify the shielding of precipitating electrons by the crustal fields.     

Electric fields within the martian magnetosphere and ion extraction: ASPERA-3 observations

Observations made by the ASPERA-3 experiment onboard the Mars Express spacecraft found within the martian magnetosphere beams of planetary ions. In the energy (E/q)-time spectrograms these beams are often displayed as dispersive-like, ascending or descending (whether the spacecraft moves away or approach the planet) structures. A linear dependence between energy gained by the beam ions and the altitude from the planet suggests their acceleration in the electric field. The values of the electric field evaluated from ion energization occur close to the typical values of the interplanetary motional electric field. This suggests an effective penetration of the solar wind electric field deep into the martian magnetosphere or generation of large fields within the magnetosphere. Two different classes of events are found. At the nominal solar wind conditions, a ‘penetration’ occurs near the terminator. At the extreme solar wind conditions, the boundary of the induced magnetosphere moves to a more dense upper atmosphere that leads to a strong scavenging of planetary ions from the dayside regions.