Il fischio che riforma: eredità del Mefistofele di Boito

In the Faustian myth, the figures of Mefistofele and Margherita contend to Doctor Faust the role of main character of the story. To consider Mefistofele as the true main character implies a priority attention attributed to the ethical-religious matter of the myth. In Italy Arrigo Boito certainly offers to the history of the myth the most original, complex and lasting interpretation in this directio

H+/Ca2+ exchange driven by the plasma membrane Ca2+-ATPase of Arabidopsis thaliana reconstituted in proteoliposomes after calmodulin-affinity purification

AbstractThe plasma membrane Ca2+-ATPase was purified from Arabidopsis thaliana cultured cells by calmodulin (CaM)-affinity chromatography and reconstituted in proteoliposomes by the freeze-thaw sonication procedure. The reconstituted enzyme catalyzed CaM-stimulated 45Ca2+ accumulation and H+ ejection, monitored by the increase of fluorescence of the pH probe pyranine entrapped in the liposomal lumen during reconstitution. Proton ejection was immediately reversed by the protonophore FCCP, indicating that it is not electrically coupled to Ca2+ uptake, but it is a primary event linked to Ca2+ uptake in the form of countertransport

Extraction of Zinc and Manganese from Alkaline and Zinc-Carbon Spent Batteries by Citric-Sulphuric Acid Solution

The paper is focused on the recovery of zinc and manganese from alkaline and zinc-carbon spent batteries. Metals are extracted by sulphuric acid leaching in the presence of citric acid as reducing agent. Leaching tests are carried out according to a24full factorial design, and empirical equations for Mn and Zn extraction yields are determined from experimental data as a function of pulp density, sulphuric acid concentration, temperature, and citric acid concentration. The highest values experimentally observed for extraction yields were 97% of manganese and 100% of zinc, under the following operating conditions: temperature40∘C, pulp density 20%, sulphuric acid concentration 1.8 M, and citric acid 40 gL-1. A second series of leaching tests is also performed to derive other empirical models to predict zinc and manganese extraction. Precipitation tests, aimed both at investigating precipitation of zinc during leaching and at evaluating recovery options of zinc and manganese, show that a quantitative precipitation of zinc can be reached but a coprecipitation of nearly 30% of manganese also takes place. The achieved results allow to propose a battery recycling process based on a countercurrent reducing leaching by citric acid in sulphuric solution

Adsorption of CO2 by synthetic zeolites

The paper reports on a possible way to recycle fluid catalytic cracking catalysts (FCCCs), widely used in oil refining operations. This research proposes a novel approach that leads to a near zero-waste process. The spent FCCC was leached by 1.5 mol/L of HNO3, HCl and H2SO4 solutions at 80°C, for 3 h with a solid to liquid ratio of 20 %wt/vol. The leaching yields for cerium and lanthanum were in the range 69-82 %. The solid residues from the leaching stage were used as base material for the synthesis of the zeolites by means of a combined thermal-hydrothermal treatment. The characterization of the zeolites demonstrated that the Na-A phase was predominant over the Na-X phase. The zeolites were tested as sorbent material for CO2 separation from CH4, in order to simulate the upgrading of biogas to biomethane. The maximum adsorption rate of CO2 was 0.778 mol CO2/kg of zeolite at 3 bar, with a resulting CH4 recovery of 62 % and purity of 97 %vol. The zeolites synthesized from spent FCCC represent a feasible solution to recover such industrial waste

manganese recovering from alkaline spent batteries by ammonium peroxodisulfate

The process of manganese removal from spent battery leaching solutions, with ammonium peroxodisulfate, prior to recovery of zinc by electrolysis is presented. The experiments were carried out according to a 2 3 full factorial design considering ammonium peroxodisulfate concentration, temperature and pH as factors investigated. The analysis of variance (ANOVA) was carried out on the precipitation yields of Mn and Zn after 30 min, 1h, 2h and 3h of reaction. Optimal conditions for obtaining Mn as MnO 2 were 20 % (NH 4 ) 2 S 2 O 8 , 90 °C and pH 6. Data from XRF and AAS during the reaction at different time are presented to analyse the kinetic behaviour of the system. The MnO 2 precipitated and solutions have been characterized by XRF and XRD. The solid samples were kept at 800 °C for 1 h to produce chemical manganese dioxide (CMD) and were characterized by cyclic voltammetry for their electrochemical activity. The overall results denoted that chemical oxidation of manganese from spent batteries leaching solutions with ammonium peroxodisulfate is a suitable method for manganese removal as MnO 2 prior zinc recovery by electrolysis, also production of a suitable product (CMD) and it could be used in a process for recycling spent batteries

Phosphorylation of serine residues in the N-terminus modulates the activity of ACA8, a plasma membrane Ca2+-ATPase of Arabidopsis thaliana

ACA8 is a plasma membrane-localized isoform of calmodulin (CaM)-regulated Ca2+-ATPase of Arabidopsis thaliana. Several phosphopeptides corresponding to portions of the regulatory N-terminus of ACA8 have been identified in phospho-proteomic studies. To mimic phosphorylation of the ACA8 N-terminus, each of the serines found to be phosphorylated in those studies (Ser19, Ser22, Ser27, Ser29, Ser57, and Ser99) has been mutated to aspartate. Mutants have been expressed in Saccharomyces cerevisiae and characterized: mutants S19D and S57D—and to a lesser extent also mutants S22D and S27D—are deregulated, as shown by their low activation by CaM and by tryptic cleavage of the N-terminus. The His-tagged N-termini of wild-type and mutant ACA8 (6His-1M-I116) were expressed in Escherichia coli, affinity-purified, and used to analyse the kinetics of CaM binding by surface plasmon resonance. All the analysed mutations affect the kinetics of interaction with CaM to some extent: in most cases, the altered kinetics result in marginal changes in affinity, with the exception of mutants S57D (KD ∼10-fold higher than wild-type ACA8) and S99D (KD about half that of wild-type ACA8). The ACA8 N-terminus is phosphorylated in vitro by two isoforms of A. thaliana calcium-dependent protein kinase (CPK1 and CPK16); phosphorylation of mutant 6His-1M-I116 peptides shows that CPK16 is able to phosphorylate the ACA8 N-terminus at Ser19 and at Ser22. The possible physiological implications of the subtle modulation of ACA8 activity by phosphorylation of its N-terminus are discussed

Fenton treatment of complex industrial wastewater: Optimization of process conditions by surface response method

Remediation of industrial wastewaters represents a stringent problem in modern society, which requires particular understanding and ad hoc solutions. In this work, we performed extensive experimental study of chemical Fenton oxidation in order to understand the optimal operative conditions to be applied in real industrial wastewaters treatment. We analyzed the effectiveness of chemical oxygen demand (COD) removal from different wastewaters within a wide range of initial COD content. We observed a maximum COD % removal of about 80%, assessing the efficiency of the process. In order to understand the role of different reagents in the final yield, we performed a factorial experimental approach on the Fenton's reagents (H(2)O(2) and Fe(2+)) and analyzed the results developing an analytical second-order model. The model depends on three variables, namely: the initial [COD(i)] of the sample, the [COD(i)]/[H(2)O(2)] ratio and [H(2)O(2)]/[Fe(2+)] ratio. We obtained an accurate description of the COD % removal in different initial conditions, with a R(2) = 0.85. In particular, we observed that optimal quantities of Fenton's reagents are a function of the initial COD of the treated wastes. (C) 2010 Elsevier B.V. All rights reserved

Zirconia and alumina based catalysts for steam reforming of naphthalene

The present paper deals with experimentation of ZrO2 and Al2O3-supported catalysts for conversion of naphthalene, chosen as tar model compound of pyrolysis or gasification syngas. In particular, the reforming capacity of active metals and promoters such as Co, Ni, Fe, Cr, Ce and Pt was tested in a fixed bed reactor at temperature from 400 to 900 degrees C. As regards ZrO2-supported catalysts, the best results were achieved by the Ni/Fe/Pt catalyst with 96% naphthalene conversion, 78% and 280% as CO and H-2 production yield at 800 degrees C. Regarding Al2O3-supported catalysts, they were more active on average than the zirconia ones, achieving a very good performance even at 500 degrees C (90-100% naphthalene conversion, 30-40% CO yield and 300-350% H-2 yield at 550 degrees C). Influence of different amounts of alumina, montmorillonite and carbon on carrier composition as well as pellets' size were also studied. Both zirconia and alumina catalysts showed deactivation at higher temperatures due to coke deposition, resulting in a strong H-2 production drop. Regeneration of catalysts by O-2 and steam as well as activation by H-2 were also studied. The activated catalyst was able to convert more than 99% naphthalene at 450 degrees C with a CO and H-2 production yield of 26% and 420%, respectively. (C) 2012 Elsevier Ltd. All rights reserved