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The main aim of this work was to assess the potential of in situ carbonation as a treatment to modify the properties of alkaline materials such as industrial soil in terms of leaching behaviour and mineralogy and to store the CO2 generated by specific treatments applied in the context of Brownfield regeneration. The process was investigated through lab-scale column carbonation experiments, in which 100% CO2 was fed through humidified stainless steel slag under ambient temperature and pressure for set reaction times. The reaction kinetics and the maximum CO2 uptake attained (5.5%), corresponding to a Ca conversion yield of 15.6%, after 4 h treatment proved slightly lower than those resulting from batch tests carried out on the same particle size fraction at enhanced operating conditions. The mineralogy of the material showed to be affected by column carbonation, exhibiting a higher calcite content and the decrease of Ca hydroxide and silicate phases. As a result of carbonation, the material showed a decrease in pH and Ca release as well as an increase in Si mobility. Furthermore, a reduction of Cr and Ba leaching, up to 63% and 96% respectively, was achieved after 2 h of reaction. However, carbonation was observed to lead to an increased leaching of V and Mo. The effects of carbonation on the leaching behaviour of the material were also investigated performing pH-dependence leaching tests and the results indicated that in situ carbonation appears to be a promising treatment to improve the properties of alkaline materials in view of their reuse on-site

Pilot-Scale Investigation of an Innovative Process for Biogas Upgrading with CO2 Capture and Storage

Abstract In this work an innovative carbon dioxide removal method that, differently from the currently employed commercial techniques, allows also to capture and store the separated CO 2 is investigated. This process, Alkali absorption with Regeneration (AwR), consists in a first step in which CO 2 is separated from the biogas by chemical absorption with an alkali aqueous solution followed by a second step in which the spent absorption solution is regenerated for reuse in the first step and the captured CO 2 is stored in a solid and thermodynamically stable form. The latter process is carried out contacting the spent absorption solution, rich in carbonate and bicarbonate ions, with a waste material characterized by a high content of calcium hydroxide and leads to the precipitation of calcium carbonate and to the regeneration of the alkali hydroxide content of the solution. The proposed processes were first investigated by preliminary laboratory and simulation analysis. On the basis of the results of these tests, air pollution control (APC) residues from Waste-to-Energy plants were selected as the material to use for the regeneration step and a pilot-scale regeneration plant was designed, built and installed in a landfill site downstream of the already existing absorption column. In this paper the sizing and design of the regeneration plant and the results of the preliminary AwR pilot- plant tests are reported. This study was carried out within the framework of the UPGAS-LOWCO2 (LIFE08/ENV/IT/000429) Life+ project

Long-range potential fluctuations and 1/f noise in hydrogenated amorphous silicon

We present a microscopic theory of the low-frequency voltage noise (known as "1/f" noise) in micrometer-thick films of hydrogenated amorphous silicon. This theory traces the noise back to the long-range fluctuations of the Coulomb potential produced by deep defects, thereby predicting the absolute noise intensity as a function of the distribution of defect activation energies. The predictions of this theory are in very good agreement with our own experiments in terms of both the absolute intensity and the temperature dependence of the noise spectra.Comment: 8 pages, 3 figures, several new parts and one new figure are added, but no conceptual revision

Performance of Anaerobic Co‑digestion of Pig Slurry with Pineapple (Ananas comosus) Bio‑waste Residues

Agro-food industries produce large amounts of bio-waste, challenging innovative valorisation strategies in the framework of circular economy principles. Anaerobic digestion technology is an interesting route to stabilise organic matter and produce biogas as a renewable energy source. This paper aimed to study the optimal performance conditions for anaerobic co-digestion (AcoD) of pig slurry with pineapple (Ananas comosus) peel bio-waste. The anaerobic digestion (AD) trials were performed at lab scale, in a continuous stirred reactor, for 16 days’ hydraulic retention time in mesophilic conditions (37 ± 1 °C). Three hydraulic retention time were performed, one for the reference scenario ( T0) and two for AcoD trials ( T1, T2). Feeding mixtures (20:80; v:v) of pineapple peel liquor and pig slurry, with an OLR of 1.46 ± 0.04 g TVS L− 1 reactor day− 1 were used during AD/AcoD trials, presenting high values for soluble chemical oxygen demand and C/N ratio. This operational conditions highlight bioenergy recovery up to 0.58 L CH4 g TVSadded −1, in comparison with that obtained with pig slurry substrate (0.31 L CH4 g VSadded −1). The AD performance showed a total volatile solids and chemical oxygen demand removal efficiency of 23% to 47% and 26% to 48%, comparing T0 with the average of T1 and T2, respectively. The digester stability, evaluated by specific energetic loading rate, was below the limit (0.4 day−1) throughout the trials. Pig slurry co-digestion with pineapple peel liquor seems to be a promising approach for potential bioenergy recovery.info:eu-repo/semantics/publishedVersio

The photochemistry of N-p-toluenesulfonyl peptides: the peptide bond as an electron donor

The scope of photobiological processes that involve absorbers within a protein matrix may be limited by the vulnerability of the peptide group to attack by highly reactive redox centers consequent upon electronic excitation. We have explored the nature of this vulnerability by undertaking comprehensive product analyses of aqueous photolysates of 12 N-p-toluene-sulfonyl peptides with systematically selected structures. The results indicate that degradation includes a major pathway that is initiated by intramolecular electron transfer in which the peptide bond serves as electron donor, and the data support the likelihood of a relay process in dipeptide derivatives