The archaeological excavations in the site of ‘Piana di San Martino’ (Pianello Val Tidone, Piacenza, Italy) discovered several fragments of pietra ollare (soapstone) artefacts, dating back to the ...Medieval period. A selection of fragments was characterized with micro‐Raman spectroscopy in order to determine their composition, in terms of main and accessory species. The morphology of the crystals and the mineral phases were also investigated with polarized‐light microscopy observations, X‐ray powder diffraction and Scanning Electron Microscopy with Energy‐Dispersive System analyses, which corroborate the Raman results. A detailed characterization was obtained on 12 fragments ascribable to pots and a millstone, made of talc‐schists or chlorite‐schists, including garnet‐bearing chlorite‐schists. Interest findings about the activities related to the use of these artefacts and the alteration processes occurred during their burial period were highlighted by the identification of specific products. Additionally, mobile Raman measurements were performed on the fragments, and a quick and effective evaluation of their composition was successfully achieved. These results highlight the use of mobile Raman instruments in the field of archaeology, specifically referred to pietra ollare findings, for which a preliminary identification may be obtained directly in situ.
Through a multi‐analytical characterization of twelve fragments of artifacts made of pietra ollare (Micro‐Raman, PLOM, XRD and SEM‐EDS), the peculiar aspects of the soapstones and alterations features were investigated. The feasibility of mobile Raman measurements on the fragments were also explored.
In this study, we applied coconut fiber-derived biochar (CFB) to a lead (Pb)-contaminated soil (at 600 mg kg−1) at 2% and 4% (w/w), in order to explore the efficacy and mechanism of CFB to immobilize ...Pb in soil during a 150-day incubation experiment. Our approach integrated various techniques namely micro-X-ray fluorescence, sequential extraction, X-ray absorption fine structure, scanning electron microscopy combined with energy dispersive X-ray spectroscopy to evaluate the Pb immobilization. Results indicated that the distribution of Pb in the studied soil was significantly affected by CFB application. The Pb content in organic matter bound fraction of the studied soil increased by 29.5% and 33.5% with 2% and 4% CFB, respectively, compared to control soil after 150-day of incubation. Lead-loaded humic acid (HA) and Pb3(PO4)2 were higher in the biochar-amended soil (2% CFB) as compared with the control soil. The CFB particles possibly offer more binding sites of PO43− and carboxylic functional groups than the binding sites of –FeO(OH), SiO32−, −Al2O3 and organic functional groups provided by the original soil particles alone (no biochar) for Pb. Overall, this study highlights that CFB can be a potential candidate to immobilize Pb for the restoration and remediation of Pb-contaminated soils.
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•Binding of Pb by organic matter in soil increased by 29.5% with 2% biochar addition.•Pb distribution was mainly on biochar surface in the soil amended with 2% biochar.•Biochar particles offered binding sites of PO3–4 and carboxylic groups for Pb.•Pb was grabbed by biochar as Pb carboxylate and Pb3(PO4)2 in biochar-amended soil.
•Atmospheric corrosion of ZnAlMg coated steel.during world wide exposures.•Localised corrosion with selective corrosion attacks in the eutectic phases.•Sulfate and chloride containing corrosion ...products in corrosion pits.•Zinc hydroxy carbonate and carbonate based LDH in outer parts of corrosion pits.
The atmospheric corrosion of zinc aluminium magnesium (ZnAlMg) coated steel was studied in a worldwide exposure in Europe, East Asia and USA. The mass loss of ZnAlMg coated steel was about 2–3 times lower compared to hot dipped galvanised steel (HDG) after 4 years exposure. The corrosion of ZnAlMg coated steel was highly localised with selective corrosion attacks in the eutectic phases of the coating. Sulfate and chloride containing corrosion products were formed in the corrosion pits while zinc hydroxy carbonate and carbonate containing layered doubly hydroxides (LDH) formed mainly in the outer parts of corrosion attacks.
Unraveling sorption mechanisms of lead (Pb) to silicon (Si)-rich biochar at molecular scale in aqueous solution are essential for the effective application of the biochars to the remediation of Pb ...and other metal(loid)s pollution in the environment. Thus, this study investigated the contributions of phytoliths and other compounds to the Pb sorption on Si-rich coconut fiber biochar (CFB500) and the corresponding sorption mechanisms using spectroscopic techniques, including the micro-X-ray fluorescence (μ-XRF), X-ray absorption fine structure (XAFS), scanning electron microscopy combined with energy dispersive X-ray spectroscopy, and X-ray diffraction. The μ-XRF and XAFS results showed that K, Ca, Cu, Mn, and Fe were released and significantly related to Pb in Pb-loaded CFB500; four major Pb species were formed with similar structures to lead carboxylate (e.g., Pb(C2H3O2)2), Pb3(PO4)2, PbSiO3, and PbCO3. On phytoliths in CFB500, Pb2+ ions were mainly sorbed on the sites of silicate with a structure similar to PbSiO3. The contribution of binding sites for Pb2+ sorption was ascribed to the outer-wall of carbon skeleton of CFB500, which was stronger than that provided by the mineral oxide aggregate and phytoliths on CFB500. Organic carbon functional groups, inorganic carbonates, silicates and phosphates on CFB500 mostly dominated the sorption sites for Pb2+. Our results suggest that CFB500 was a promising material for the remediation of Pb-contaminated aqueous environments (e.g., wastewater).
Unraveling sorption mechanism of potentially toxic elements (PTEs) by Si-rich biochar can provide guidance for application of biochar-based materials to environmental remediation. Display omitted
•Distribution of Pb in Si-rich coconut biochar was related to K, Ca, Cu, Mn and Fe.•Lead carboxylate, Pb3(PO4)2, and PbSiO3 were major Pb species on Pb-loaded biochar.•Silicates were the dominant sorption sites on biochar's phytoliths for Pb2+.•Pb2+ was mainly sorbed by organic skeleton of biochar with a C−O−Pb or C−O−Pb−O−C.
Chrysotile, one of the six regulated asbestos minerals, is classified as carcinogenic to humans by the International Agency for Research on Cancer. The Balangero mine (Turin, Italy) was the largest ...asbestos mine in Europe, providing extraction of chrysotile fibers until 1990. Chrysotile from Balangero is currently of great interest in fibers toxicity studies focused on the understanding of the mechanisms that induce lung malignancies. One of the crucial factors in the biochemical reactions is the presence of Fe at the fibers surface. Surface reactivity is responsible for the generation of reactive oxygen species, which play an important role in asbestos cyto‐genotoxicity. Moreover, the dissolution of Fe‐bearing phases in the acidic environment of the lysosomes might be considered as possible release of hazardous Fe ions in the lungs. Here, chrysotile from Balangero was characterized by micro‐Raman spectroscopy and scanning electron microscope‐energy dispersive system (SEM‐EDS) analysis to identify the Fe‐bearing impurities associated with asbestos fibers. Micrometric crystals were recognized as Fe oxides, carbonates, and sulfides. Uncommonly reported phases in asbestos minerals were also identified, mainly as mackinawite (Fe(II)S), in different forms. The nature of the Fe compounds containing both Fe(II) and Fe(III) species was verified by micro‐Raman spectroscopy combined with SEM‐EDS analysis.
Fe‐bearing impurities associated with asbestos fibers were identified as Fe oxides, carbonates, and sulfides, including uncommonly reported phases in asbestos minerals.
Corrosion effects on copper exposed in a humid atmosphere with formic acid (mimicking indoor corrosion) have been explored through successive increase in surface lateral resolution from macroscale ...(IRRAS, GIXRD) over microscale (LOM, SEM, IR microscopy) to nanoscale (Nano-FTIR, FIB/SEM/EDS). Initial more uniform growth of Cu2O is followed by more varying topography and thickness until local removal of Cu2O enables the aqueous adlayer to react with the copper substrate. Local formation of Cu(OH)(HCOO) and adjacent Cu2O provide microscopic and spectroscopic evidence of corrosion cells. Nano-FTIR shows that the density of Cu(OH)(HCOO) nuclei, but not their size, increases with exposure time.
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•Corrosion effects on copper explored at the macroscale, microscale, and nanoscale levels.•Techniques include IRRAS, GIXRD, LOM, SEM, IR microscopy, Nano-FTIR, and FIB/SEM/EDS.•Coherent mechanistic picture obtained from all techniques.•Nanoscale images and distribution of Cu(OH)(HCOO) nuclei visualised with Nano-FTIR.•Direct microscopic and spectroscopic evidence of corrosion cells.
The novelty of the work is to investigate the application of two new epoxy resins namely as hexaglycidyl N-phenylaminopropoxy-N.N.N-triphenyl propane-1.3-diamine (ERH) and octaglycidyl ...N.N.N.N-tetraphenylamino-N.N.N.N-tetrapropoxy methylene dianiline (ERO) as potential corrosion inhibitors for carbon steel (CS) in 1 M HCl medium. The corrosion resistance was quantified by various techniques namely polarization curve (PC), electrochemical measurement (EIS), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS), global quantum chemical descriptors (GQCDs) and molecular dynamics (MDs) simulation. EIS data suggest that the corrosion efficiency of ERO (94.1%) is higher than that of the ERH (89.7%) in HCl medium at room temperature. Further, PC results indicate that the corrosion efficiency of ERO (95.6%) is higher than that of the ERH (95.4%) in the presence of 10−3 M of studied inhibitors and also PC data suggest that the two epoxy resins investigated acted as a mixed type inhibitor. Langmuir adsorption isotherm is the most acceptable technique or method to describe the ERH and ERO epoxy resins adsorption on the CS area. SEM/EDS data display the two ERH and ERO epoxy resins can be stopped the acid attack though chemisorption on the CS surface. GQCDs calculations were applied by density functional theory (B3LYP and WB97XD) and Hartree-Fock (HF) methods using 6-31G(d,p) basis sets to study the inhibition efficiencies of the two epoxy resins inhibitors. GQCDs such as EHOMO, ELUMO, energy gaps, electronegativity, hardness, electrophilicity, fractions of electron transferred were calculated and discussed. Other energetic parameters such the free energy of adsorption, the metal-inhibitor energy gaps, the electron transfer back-donation energy and the initial molecule-metal interaction energy were also calculated and discussed. The molecular dynamics simulation approach was performed to investigate the adsorption behaviors of the investigated inhibitors on Fe(110) surface. The results obtained using the computational methods and the molecular dynamics simulations reveal that the ERO inhibitor has more inhibitory effect against corrosion of the Fe-metal than that of the ERH inhibitor. The obtained theoretical results were adapted with experimental inhibition efficiency results.
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•Two epoxy resins (ERH and ERO) were synthesized and investigated as potential anticorrosive protection.•Corrosion efficiency of ERO is higher than that of the ERH in HCl solution.•SEM/EDS analysis displayed the both ERH and ERO inhibitors could effectively block the acids attack by chemisorption.•Theoretically approaches are in good agreement with experimental data.
While large quantities of studies on microplastics in the marine environment have been widely carried out, few were available in the freshwater environment. The occurrence and characteristics, ...including composition, abundance, surface texture and interaction with heavy metals, of microplastics in the surface sediments from Beijiang River littoral zone were investigated. The concentrations of microplastics ranged from 178 ± 69 to 544 ± 107 items/kg sediment. SEM images illustrated that pits, fractures, flakes and adhering particles were the common patterns of degradation. Chemical weathering of microplastics was also observed and confirmed by μ-FTIR. EDS spectra displayed difference in the elemental types of metals on the different surface sites of individual microplastic, indicating that some metals carried by microplastics were not inherent but were derived from the environment. The content of metals (Ni, Cd, Pb, Cu, Zn and Ti) in microplastics after ultrasonic cleaning has been analyzed by ICP-MS. Based on data from the long-term sorption of metals by microplastics and a comparison of metal burden between microplastics, macroplastics and fresh plastic products, we suggested that the majority of heavy metals carried by microplastics were derived from inherent load.
•Occurrence and characteristics of microplastics from Beijiang river sediment were investigated.•A combination of μ-FTIR and SEM illustrated the chemical degradation of microplastics.•The content of metals (Ni, Cd, Pb, Cu, Zn and Ti) in microplastics is investigated by ICP-MS.•We suggested that the majority of heavy metals carried by microplastics were derived from inherent load.
This research article aims to study the neutron and charged particle attenuation properties of volcanic rocks collected from the western region of Saudi Arabia. The rock samples labeled as VR1, VR2, ...VR3, and VR4 were experimentally investigated by a Field Emission Scanning Electron Microscope (FE-SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). The neutron transmission factor (TF) was estimated by using the Monte Carlo technique for different thicknesses varying from 0 to 3 mm. Moreover, we studied the charged particles' interaction properties with the present volcanic rocks for projectile energy up to 2.5 MeV. The obtained results reveal that the neutron TF decreased from 95.2, 95.8, 94.9, and 95.3 % at 0.5 mm to 74.4, 77.4, 73.4, and 75.1 % at 3 mm for the rock samples of VR1, VR2, VR3, and VR4, respectively. We found that the maximum projectile range (ℜ) occurred at the low energy region (0.2 MeV) for charged particle interactions. In comparison, the minimum ℜ occurred at the high energy level (2.5 MeV). Additionally, the values of ℜ come in the order of ℜ electron > ℜ proton > ℜ alpha > ℜ carbon with the minimum values of 185.6, 221.8, 178.8, and 189.8 μm in the case of the electron, and with the values of 0.696, 0.8141, 0.669, and 0.716 μm in the case of carbon ion for VR1, VR2, VR3, and VR4, respectively. This result revealed the VR3 rock sample as a superior shielding material against neutron beams and charged particles among the studied volcanic rocks.
•Four volcanic rocks were collected, prepared, and studied as radiation shields.•Energy-Dispersive X-ray Spectroscopy (EDS) was applied for the rock samples.•The neutron shielding ability is examined by using Geant4 simulations.•The highest neutron transmission factor was observed for VR3 rock sample.•VR3 rock sample has a superior shielding ability against neutrons beam and charged particles.
A novel chitosan oligosaccharide macromolecule carrying a glucose moiety (COS-g-Glu) has been synthesized and used as a non-toxic, durable, and biodegradable inhibitor of mild steel corrosion in ...acidic medium (1.0 M HCl). This macromolecule was synthesized by grafting a glucose moiety on Chitosan, and characterized by FT-IR, 1H and 13C NMR. The acid corrosion inhibiting effect of this biodegradable macromolecule is obtained by experimental electrochemical characterization (EIS and PDP), surface Scanning Electron Spectroscopy (SEM), Energy Dispersive Spectroscopy (EDS), infrared (FT-IR), and Atomic Force Microscopy (AFM). Corrosive acidic solutions were identified by UV–visible spectroscopy (UV–vis) and by ICP-OES spectrometry. Electrochemical tests show that the inhibition efficiency increases with increasing concentration of the inhibitor and reaches an optimum value of 97% at 10−3 M. The thermodynamic parameters, and steel surface characterization methods confirmed the adsorption of COS-g-Glu. The results obtained from the DFT, and MD calculations correlate with the results obtained experimentally.
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•New carbohydrate polymer chitosan synthesized and characterized as corrosion inhibitor for mild steel.•Polarization studies revealed that COS-g-Glu is a mixed-type of inhibitor.•Surface morphology analysis confirmed the inhibitive character of COS-g-Glu.•Theoretical insights into the corrosion inhibition performance of COS-g-Glu were performed.
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