Aqua Traiana, a Roman infrastructure embedded in the present: the mineralogical perspective

Construction materials from the internal ducts of Aqua Traiana, a still operative Roman aqueduct built in 109 AD to supply water to Rome, were characterized by optical microscopy (OM), scanning electron microscopy (SEM-EDS), X-ray powder diffraction (XRPD) and electron microprobe analysis (EMPA). Petrographic analysis and XRPD revealed that mortar aggregates are compatible with Vitruvius’ harena fossicia and allowed the distinction of the original mortars from those of the 17th-century papal restoration. The first showed an amorphous binder while the latter have a typical lime binder. By SEM-EDS and EMPA, the microstructure of mortar aggregates was analyzed and the composition of specific minerals quantified. Microanalysis testifies the Romans’ great expertise in the selection of pozzolanic building materials, giving evidence of the possible use of local tuffs from the Sabatini Volcanic District. It also confirms the exploitation of red pozzolan from the Roman Magmatic Province, specifically from the Alban Hills district. OM also proves a high compatibility with local supplies for bricks and cocciopesto. Of these, the first were fired at moderately low temperature, while the latter show an amorphous binder as in the original Trajan mortars. All building materials thus stand for similar technological choices and a coeval production

Preparation of hydrogel composites using a sustainable approach for In situ Silver nanoparticles formation

The recognized antibacterial properties of silver nanoparticles (AgNPs) characterize them as attractive nanomaterials for developing new bioactive materials less prone to the development of antibiotic resistance. In this work, we developed new composites based on self-assembling Fmoc-Phe3 peptide hydrogels impregnated with in situ prepared AgNPs. Different methodologies, from traditional to innovative and eco-sustainable, were compared. The obtained composites were characterized from a hydrodynamic, structural, and morphological point of view, using different techniques such as DLS, SEM, and rheological measurements to evaluate how the choice of the reducing agent determines the characteristics of AgNPs and how their presence within the hydrogel affects their structure and properties. Moreover, the antibacterial properties of these composites were tested against S. aureus, a major human pathogen responsible for a wide range of clinical infections. Results demonstrated that the hydrogel composites containing AgNPs (hgel@AgNPs) could represent promising biomaterials for treating S. aureus-related infections

How microanalysis can be discriminant on black Pompeian wares

In the present work the advantages of punctual approaches are discussed in the discrimination of black wares from the Sanctuary of Venus Fisica (Pompeii, Italy), dated between the 2nd and 1st century BC. Black-gloss ware and "bucchero" samples are analyzed by a multi-analytical approach including optical microscopy (OM), X-ray powder diffraction (XRPD), scanning electron microscopy with Energy Dispersive Spectroscopy (SEM-EDS) and electron microprobe analysis (EMPA) to investigate the mineralogical and petrographic features of these artefacts. Grain size, firing conditions and potter’s expertise influenced the final appearance of the superficial decorative black layer. In addition, punctual chemical analysis was fundamental to verify the archaeological indication of specific production sites

Lime production in the Late Chalcolithic period: the case of Arslantepe (Eastern Anatolia)

Plaster and mortar samples from Arslantepe (Turkey) hold potential to provide unique information about the lime production and adhibition during the Late Chalcolithic period (4th millennium BCE). A multi-analytical approach including polarized light microscopy (PLM), X-ray powder diffraction (XRPD), and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) has been applied to characterize mortar samples from temple C and elite residences dated back to the late Chalcolithic 3–4 (3800–3400 BCE). A marly limestone has been identified as starting raw material for the lime production, probably coming from two different sources (local and brought from a different part of the Malatya plain). Moreover, different aggregate selection and the use of different production techniques were also detected in the samples, which are probably related to the function of the buildings. Evidence of a re-plastering process was also detected in the two elite houses, which probably refers to a routine maintenance process

Toxic metals remediation in water and soil by phosphate treatment

Toxic metals pollution of water and soil is one of the most environmental concerns. Unlike organic contaminants, metals persist for a long time after their introduction in the environment adversely affecting water resources and agricultural productivity. Numerous studies demonstrated the effectiveness of phosphate treatment as a cost-effective and environmentally positive remediation technology of contaminated waters and soils. The goal is to reduce mobility and biovailability of toxic metals through the formation of metal phosphates with low solubility and which are stable under a wide range of environmental conditions. The possible reaction mechanisms for metal remediation include ion exchange processes, surface complexation, dissolution of phosphate materials and precipitation of new metal-bearing phosphates, and substitution by metals during recrystallization (coprecipitation) of phosphate minerals. Several natural and synthetic phosphate materials such as hydroxyapatite (HA), phosphate rock (PR), eggshell-derived HA, diammonium phosphate, triple superphosphate, etc. have been used. However, contaminated waters and soils are multi-component systems and the competition among toxic metals can affect the removal efficiency of phosphate amendments. Our results have shown that synthetic HA and PR can effectively immobilize toxic metals such as Pb, Cd, Cu, Zn, Ni and Co in polluted waters and soils. In particular, synthetic HA is able to remove Pb, Cd, Cu and Zn from aqueous solutions both in single- and multi-metal (Pb + Cd + Cu + Zn) systems. The removal efficiency generally ranges from 94 to 98% in single-metal solutions with reduced efficiency in multi-metal systems. Also in metal contaminated soils from sulfide mine areas the application of HA and PR results in the reduction of reactive and biovailable metal fractions in more stable forms. In general, our results suggest that the main mineralogical composition of the soils in mine areas may impact the effectiveness of metal immobilization. Although PR has lower removal capacity than synthetic HA, the application of PR in contaminated soils can minimize the potential risk of eutrophication due to the use of highly soluble phosphate sources. Phosphate-induced metal immobilization represents a cost-effective and environmentally friendly remedial strategy for contaminated waters and soils

Procedure for dissolving wolframite in order to determine trace elements by atomic absorption spectrometry

An analytical procedure for dissolving wolframite in order to determine trace elements by atomic absorption is reported. After decomposition of the mineral by alkaline fusion, the cooled flux is dissolved by heating with aqua regia. The finely crystalline precipitate of tungstite, which forms on standing, is filtered and dissolved by heating with aqua regia. Tungstite forms again in the latter solution and the filtration and solubilization are repeated until the solution contains negligible amounts of trace elements. Following this procedure, trace elements in 35 samples of natural wolframite have been dissolved and the solutions obtained have been analyzed by atomic absorption spectrometry for Fe, Mn, Cu, Zn, Pb, Co, Ni and Cd