Implementing magnetically-active Sn-based nanocomposites in hexavalent chromium removal from drinking water.

A novel nanocomposite consisting of FeO-loaded tin oxyhydroxy-chloride is demonstrated as an efficient adsorbent for the removal of hexavalent chromium in compliance to the new drinking water regulation. This study introduces a continuous-flow production of the nanocomposite through the separate synthesis of (i) 40 nm FeO nanoparticles and (ii) multilayered spherical arrangements of a tin hydroxy-chloride identified as abhurite, before the application of a wet-blending process. The homogeneous distribution of FeO nanoparticles on the abhurite's morphology, features nanocomposite with magnetic response whereas the 10 % loaded nanocomposite preserves a Cr(VI) uptake capacity of 7.

Se(IV)/Se(VI) adsorption mechanisms on natural and on Ca-modified zeolite for Mediterranean soils amended with the modified zeolite: prospects for agronomic applications.

In the present study, the ability of a modified CaCl zeolite (Ca-Z) to both increase Se(IV) availability and restrict Se(VI) mobility in soils is examined. As it was resulted from batch experiments and verified by X-ray absorption fine structure (XAFS) and X-ray fluorescence (XRF) spectroscopies, higher amounts of both Se species adsorbed on Ca-Z compared to natural zeolite (Z-N) forming outer-sphere complexes while the oxidation state did not alter during agitation of samples. Thereafter, Ca-Z was incorporated in six Greek soils, divided into acid and alkaline, at a 20% (w/w) rate and a series of equilibrium batch experiments were performed with soils alone and soils-Ca-Z mixtures to investigate sorption and desorption processes and mechanisms.

Enhanced thermal conductivity in percolating nanocomposites: a molecular dynamics investigation.

In this work we present a molecular dynamics investigation of thermal transport in a silica-gallium nitride nanocomposite. A surprising enhancement of the thermal conductivity for crystalline volume fractions larger than 5% is found, which cannot be predicted by an effective medium approach, not even including percolation effects, the model systematically leading to an underestimation of the effective thermal conductivity. The behavior can instead be reproduced if an effective volume fraction twice larger than the real one is assumed, which translates into a percolation effect surprisingly stronger than the usual one.

Natural radioactivity studies in a paleontology site and paleoclimate interpretation of the last 8 Mya.

Fossil bones and sediments from different horizons of the Upper Miocene paleontological site of Platania, Drama-Greece were studied using U, U, Th series and K measurements obtained by γ-spectroscopy. Additionally, SEM and XRF analysis was applied to bone and sediment samples while a lithological analysis of the sediments was also carried out. The Ra/U ratios in the fossilization layers are attributed to the U depletion from the sediment and its incorporation into the fossils.

High pressure Raman study of type-I collagen.

The high pressure response of type-I collagen from bovine Achilles tendon is investigated with micro-Raman spectroscopy. Fluorinert™ and methanol-ethanol mixtures were used as pressure transmitting media (PTM) in a diamond anvil cell. The Raman spectrum of collagen is dominated by three bands centred at approximately 1450, 1660 and 2930 cm , attributed to C-H deformation, C=O stretching of the peptide bond (amide-I band) and C-H stretching modes respectively.

Sn(II) oxy-hydroxides as potential adsorbents for Cr(VI)-uptake from drinking water: An X-ray absorption study.

The feasibility of implementing a Sn(II) oxy-hydroxide (Sn6O4(OH)4) for the reduction and adsorption of Cr(VI) in drinking water treatment was investigated using XAFS spectroscopies at the Cr-K-edge. The analysis of the Cr-K-edge XANES and EXAFS spectra verified the effective use of Sn6O4(OH)4 for successful Cr(VI) removal. Adsorption isotherms, as well as dynamic Rapid Small Scale Test (RSSCT) in NSF water matrix showed that Sn6O4(OH)4 can decrease Cr(VI) concentration below the upcoming regulation limit of 10μg/L for drinking water.

Composition and hydrophilicity control of Mn-doped ferrite (MnxFe3-xO4) nanoparticles induced by polyol differentiation.

Manganese doped ferrite (MnxFe3-xO4) nanoparticles with x = 0.29-0.77 were prepared under solvothermal conditions in the presence solely of a polyol using the trivalent manganese and iron acetylacetonates as precursors.

A novel approach for arsenic adsorbents regeneration using MgO.

An integrated procedure for the regeneration of iron oxy-hydroxide arsenic adsorbents by granulated MgO is proposed in this study. A continuous recirculation configuration, with a NaOH solution flowing sequentially through the saturated adsorbent (leaching step) and the MgO (adsorption step) column beds, was optimized by utilizing the high arsenic adsorption efficiency of MgO at strong alkaline environments. Experimental results indicated that the total amount of leached arsenic was captured by MgO whereas the regenerated iron oxy-hydroxide recovered around 80% of its removal capacity upon reuse.

Tetravalent manganese feroxyhyte: a novel nanoadsorbent equally selective for As(III) and As(V) removal from drinking water.

The development of a single-phase Fe/Mn oxy-hydroxide (δ-Fe0.76Mn0.24OOH), highly efficient at adsorbing both As(III) and As(V), is reported.