Search

Electromethanogenesis is an innovative technology that uses a microbial electrochemical system to produce methane from CO2, in a power-to-gas (BEP2G) concept. The results of experimental tests of new and cost-effective carbonaceous materials for electrode are presented here. The study aims at optimizing electromethanogenesis processes at laboratory level in mesothermic condition. As part of the experiments, hydrogenotrophic microorganisms (Family Metanobacteriaceae of Archaea domains) were selected from a mixed consortium taken from a biogas digestate and inoculated in double-chamber bioelectrochemical systems. The maximum amount of methane produced was 0.3 - 0.8 mol/m2g (normalized to the cathode area) with carbon cloth electrodes. Aiming at improving the methane productivity, innovative materials for the electrodes were now studied, creating porous high-surface composites, and studying nitrogen carbons doped with Cu and hydroxyapatite (Multicomposite Cu@/HAP/C), as chemical catalysts for CO2 reduction (CO2RR). The description of the procedure for the Multicomposite Cu@/HAP/C production is reported in detail.

Addressing the need for cost-efficient and environmentally friendly electrode materials for large-scale applications of bioelectrochemical systems, this study implemented the principles of circular economy to produce biochar- and hydroxyapatite/biochar-based conductive cathodes to be employed in clean and green technologies for wastewater treatment. Silverskin, the byproduct of coffee roasting responsible for generating significant waste worldwide, was subjected to a pyrolysis process to produce conductive biochar, then characterized in terms of physico-chemical properties. Biochar-based inks were formulated and employed to produce microporous layers on carbon cloth, finally used as cathodic materials in microbial fuel cells systems. The presence of hydroxyapatite in biochar-based composites was also evaluated with the goal of combining the remediation activity of biochar towards dissolved organic compounds, with that of hydroxyapatite towards inorganic ionic pollutants (such as Cd(II) and Zn(II)). Despite underperforming compared to other more technological and optimized materials, waste-derived biochar and its composite with hydroxyapatite were demonstrated to open novel frontiers in design and architecture of “multi-pollutants targeted” smarter bioelectrochemical systems, where not only microcurrent production, but a broader range of wastewater treatment can be addressed. [ABSTRACT FROM AUTHOR]

Two 11th- and 12th-century entrance doors from the Basilica di San Marco in Venice, made of different copper alloys and woods, were non-invasively examined in situ. The chemical composition of the metals, the way in which different metal parts were joined together, the tree species used to construct the supporting structures and the age of the wood are determined. A portable ED-XRF instrument and optical microscopes were used. The doors were also photographed to produce high-resolution orthophotos and 3D models. The metal parts of the doors were made of leaded tin-bronze and quaternary Cu-Sn-Zn-Pb alloys and were mounted on a wooden multi-layer structure of larch and silver fir; the dendrochronological dates of some of the larch boards are 1965, teminus post quem. [ABSTRACT FROM AUTHOR]

A method for estimating the composition of the metal core in historical and archaeological artifacts using surface X-ray fluorescence (XRF) data is described. The method is based on the combination of fluorescence data recorded at points of the object with different degrees of corrosion exploiting the general phenomenon of demetallation of the less noble components of the metal alloy. A theoretical approach is provided using the Johnson–Mehl–Avrami–Erofeev-Kolmogorov (JMAEK) formalism to describe demetallation. Experimental data for binary Zn Cu brass and Pb- and Sn-containing brass from Hofkirche in Innsbruck agree satisfactorily with the model. [Display omitted] • XRF data on historical metallic artifacts are treated. • Data from brass statues objects are representative of dezincication processes. • Such data can be described in terms of the Johnson–Mehl–Avrami–Erofeev-Kolmogorov (JMAEK) equation. • The JMAEK formalism is applied to determine the composition of the metal core. [ABSTRACT FROM AUTHOR]