Selective leaching of precious metals from electrical and electronic equipment through hydrometallurgical methods

The rapid human evolution has improved the quality of our lives through the use of technology. This not only resulted in increased raw materials extraction but also in the production of a worrying amount of electronic wastes. Indeed, in 2019 worldwide production of Electronic and Electric Equipment Waste (WEEE) was worth 50 million tons, causing several disadvantages such as the reduced space in landfills and massive shipping to countries with less restrictive regulations. On the other side, the billionaire electrical devices market is causing a significant increase in Precious Metals (PM) demand. Nowadays, the economic importance of PMs is as high as their supply risk. The answer to this problem consists of finding selective methods to extract and raffinate precious metals from disposed WEEE. On average, WEEEs contain around 30 % of plastics, 30 % ceramics, and 40 % metals; among these only around 0.1 % is characterized by PMs, such as gold, silver, rhodium, platinum, and palladium. The separation of PMs from other non-precious components is generally obtained using pyrometallurgy, which consists of fusing the wastes at temperatures up to 1500 ÷ 1700 °C. However, this method produces toxic gaseous byproducts and implies high energy costs. A possible alternative is given by hydrometallurgical processes, consisting of leaching the WEEE with solutions containing acids and oxidants at temperatures lower than 100°C. One of the main issues of the hydrometallurgical process is to leach copper and other non-precious base-metals selectively while keeping PMs in the solid-state. In this work, we report preliminary results of equilibrium and kinetic leaching tests in a well-stirred batch reactor, aimed at the optimization of the main operating parameters of a hydrometallurgical process for selective leaching of copper and other base-metals from Wasted Printed Circuit Boards (WPCBs). In particular, experiments have been carried out at different HCl and NaCl concentrations of the leaching solutions, exploring also the effect of temperature variation (20, 50, and 70 °C)

Enhancing the Accuracy of Ab Initio Molecular Dynamics by Fine Tuning of Effective Two-Body Interactions: Acetonitrile as a Test Case

Grimme’s dispersion-corrected density functional theory (DFT-D) methods have emerged among the most practical approaches to perform accurate quantum mechanical calculations on molecular systems ranging from small clusters to microscopic and mesoscopic samples, i.e., including hundreds or thousands of molecules. Moreover, DFT-D functionals can be easily integrated into popular ab initio molecular dynamics (MD) software packages to carry out first-principles condensed-phase simulations at an affordable computational cost. Here, starting from the well-established D3 version of the dispersion-correction term, we present a simple protocol to improve the accurate description of the intermolecular interactions of molecular clusters of growing size, considering acetonitrile as a test case. Optimization of the interaction energy was performed with reference to diffusion quantum Monte Carlo calculations, successfully reaching the same inherent accuracy of the latter (statistical error of ∼0.1 kcal/mol per molecule). The refined DFT-D3 model was then used to perform ab initio MD simulations of liquid acetonitrile, again showing significant improvements toward available experimental data with respect to the default correction

Cementitious composite materials for thermal energy storage applications: a preliminary characterization and theoretical analysis

The lack of robust and low-cost sorbent materials still represents a formidable technological barrier for long-term storage of (renewable) thermal energy and more generally for Adsorptive Heat Transformations—AHT. In this work, we introduce a novel approach for synthesizing cement-based composite sorbent materials. In fact, considering the number of available hygrosopic salts that can be accommodated into a cementitious matrix—whose morphological properties can be also fine-tuned—the new proposed in situ synthesis paves the way to the generation of an entire new class of possible sorbents for AHT. Here, solely focusing on magnesium sulfate in a class G cement matrix, we show preliminary morphological, mechanical and calorimetric characterization of sub-optimal material samples. Our analysis enables us to theoretically estimate one of the most important figures of merit for the considered applications, namely the energy density which was found to range within 0.088–0.2 GJ/m3 (for the best tested sample) under reasonable operating conditions for space heating applications and temperate climate. The above estimates are found to be lower than other composite materials in the literature. Nonetheless, although no special material optimization has been implemented, our samples already compare favourably with most of the known materials in terms of specific cost of stored energy. Finally, an interesting aspect is found in the ageing tests under water sorption-desorption cycling, where a negligible variation in the adsorption capability is demonstrated after over one-hundred cycles

Expanding the Chemical Space of Tetracyanobuta-1,3-diene (TCBD) through a Cyano-Diels-Alder Reaction: Synthesis, Structure, and Physicochemical Properties of an Anthryl-fused-TCBD Derivative

Tetracyanobuta-1,3-diene (TCBD) is a powerful and versatile electron-acceptor moiety widely used for the preparation of electroactive conjugates. While many reports addressing its electron-accepting capability have appeared in the literature, significantly scarcer are those dealing with its chemical modification, a relevant topic which allows to broaden the chemical space of this interesting functional unit. Here, we report on the first example of a high-yielding cyano-Diels-Alder (CDA) reaction between TCBD, that is, where a nitrile group acts as a dienophile, and an anthryl moiety, that is, acting as a diene. The resulting anthryl-fused-TCBD derivative, which structure was unambiguously identified by X-ray diffraction, shows high thermal stability, remarkable electron-accepting capability, and interesting electronic ground- and excited-state features, as characterized by a thorough theoretical, electrochemical, and photophysical investigation. Moreover, a detailed kinetic analysis of the intramolecular CDA reaction transforming the anthryl-TCBD-based reactant into the anthryl-fused-TCBD product was carried out at different temperatures

Major practicum as a learning site for exercise science professionals: A pilot study

Exercise science is now an integral part of the allied health framework in Australia and graduates from accredited programmes are equipped with skills recognised as being important in the prevention and management of lifestyle-related diseases. This pilot study sought to determine the experiences of 11 final-year exercise science students in their major practicum and identify skills learned and developed while on placement. Analysis of the interview data established that the students worked with clients from a broad range of sociocultural and socioeconomic backgrounds, both within and between practicum sites; the students' experiences and their preparedness to engage with clients from different backgrounds varied as a result. Although the students generally reported being technically skilled for their major placement, many reported being underprepared to deal with people from different backgrounds. However, all participants held that their interpersonal skills greatly improved in response to their placement and several remarked that they developed their problem-solving skills through watching and assisting their supervisors work with clients. The present study confirms the practicum as a critical learning site for improving communication and problem-solving skills with exercise science and exercise physiology students

Statistical Mechanics and Thermodynamics of Simulated Ionic Solutions

In this work we combine molecular dynamics simulations with the quasi-Gaussian entropy (QGE) theory to model the statistical mechanics and thermodynamics of ionic solutions. Results showed that the use of the gamma state model provides an excellent theoretical description of the solution behavior over a wide range of temperature. Such an approach makes possible, at relatively low computational costs, the evaluation of partial molar properties such as free energy and entropy which require a heavy computational effort to be estimated with the usual procedures

Management of Hypothyroidism in Internal Medicine: Patient Profile and Effects of an Educational Programme in the Cluster-Randomized FADOI TIAMO Study.

Background and aims: There is still limited knowledge regarding the clinical profile and appropriateness of treatment in patients with hypothyroidism hospitalized in Internal Medicine (IM) Departments in Italy. The aim of this study is to evaluate: 1) the characteristics of patients and possible deviations from national and international clinical practice recommendations (CPRs) in evidence-based guidelines (EBGs); 2) the improvement of patient management by means of a standardized educational programme (EP). Methods: A nationwide multicentre study, comprising two replications of a retrospective survey (phases 1 and 3) with an intervening EP (phase 2) in half of the centres and no EP in the other half, was conducted. The EP was based on outreach visits. Centres were assigned to the two arms of the study, labelled the training group (TG) and control group (CG) respectively, by cluster randomization. Four EBGs and 39 CPRs provided the basis on which 22 treatment management indicators were identified (7 referring to the time of hospital admission, 15 to post-admission). Results: The 21 participating centres recruited 587 hospitalized patients with hypothyroidism, 421 of which were females (71.7%, mean age 74.1 + 14.4 yrs): 318 in phase 1 and 269 in phase 3. The cause of hypothyroidism was unknown in 282 patients (48%). Evaluation at the time of admission identified satisfactory adherence to CPRs (>50%) for 63.6% of the indicators. In the phase 3, TG centres showed significant improvement vs CG in 4 of the 15 post-admission indicators, while 1 out of 15 was significantly worse. Conclusions: The EP based on outreach visits significantly improved some indicators in the management of patients with hypothyroidism, with specific reference to appropriateness of TSH dosage and levothyroxine (LT4) treatment modality. Clinical trial registration: ClinicalTrials.gov, identifier NCT05314790

L’internista ospedaliero nella gestione del paziente diabetico complesso

L’internista deve occuparsi (e rioccuparsi) del paziente diabetico complesso in Ospedale A. Fontanella, L. Magnani Diagnosi, classificazione, epidemiologia clinica del diabete mellito V. Provenzano, D. Brancato Up-date degli studi disponibili P. Gnerre, T.M. Attardo, A. Maffettone, G. Beltramello Il diabete mellito costituisce ancora un equivalente di rischio cardiovascolare? G. Augello, T.M. Attardo Le terapie del diabete tipo 2 sono tutte uguali ai fini della riduzione della morbilità e mortalità cardiovascolare? V. Provenzano Le nuove tecnologie nella cura del diabete mellito D. Brancato, V. Provenzano Insuline prandiali e insuline basali R. Pastorelli Quali target nel diabete mellito: il dogma dell’emoglobina glicata è davvero imprescindibile? V. Manicardi Il controllo dell’iperglicemia nel paziente anziano polipatologico: è sempre necessario iniziare l’insulina? G. Gulli, M. Nizzoli La nefropatia diabetica F. Salvati, D. Manfellotto, M. Stornello Cirrosi epatica e diabete M. Imparato, L. Fontanella La terapia personalizzata nel diabete di tipo 2 A. Maffettone, C. Peirce, M. Rinaldi La gestione dell’iperglicemia nel paziente critico e instabile C. Nozzoli La disfunzione erettile nel paziente diabetico di tipo 2 N. Artom, A. Bosio, G. Pinna Quali obiettivi di approccio integrato nella gestione del diabete mellito? E. Romboli, D. Panuccio Iperglicemia, normoglicemia ed ipoglicemia nei pazienti anziani fragili: situazioni a rischio, politerapia e comorbilità A. Greco, M. Greco, D. Sancarlo, F. Addante, G. D’Onofrio, D. Antonacci, S. De Cosmo L’impatto clinico-prognostico dell’ipoglicemia nel paziente ospedalizzato V. Borzì, L. Morbidoni, A. Fontanella L’internista chiamato in consulenza per un diabete gestazionale: quale approccio pragmatico? P. Novati, L. Sali La frugalità nella gestione del diabete mellito: qualità assistenziale, governo clinico e costi correlati P. Gnerre, G. Carta, D. Montemurro La gestione dell’iperglicemia in area medica, ma senza esagerare. L. Magnani, G. Beltramello APPENDICE I Un approccio pragmatico per la valutazione globale e la gestione del paziente diabetico F. Pieralli, A. Crociani, C. Bazzini APPENDICE II Le insuline e i farmaci ipoglicemizzanti orali disponibili P. Zuccheri, L. Alberghini, E. Sora APPENDICE III Le scale di correzione insulinica: pro e contro V. Borz