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•Cellulose nanocrystals (CNC) were successfully extracted from Diss stems.•Chemical and enzymatic pretreated celluloses from Diss were acid hydrolyzed.•CNC from enzymatic treated ...fibres (E-CNC) exhibited enhanced thermal stability.•CNC from chemically treated fibres (C-CNC) have reduced size compared to E-CNC.
The aim of this research activity was based on the revalorization of Amplodesmos mauritanicus (Diss), an African grass largely presented in the Algerian territory. Diss stems were selected as native botanic material for the extraction of cellulose nanocrystals (CNC). Two different pretreatment steps were carried out to extract CNC from Amplodesmos mauritanicus stems and the following acidic hydrolysis procedure allowed to extract/obtain cellulose nanocrystals in aqueous suspension. The effect of the two different pretreatments, based essentially on chemical or enzymatic treatments, were deeply investigated and the properties compared. Field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were considered for the characterization of raw material, chemical or enzymatic treated Diss stems and CNC extracted from both chemical and enzymatic pretreated cellulose.
► We separated Zn from Mn in zinc–carbon and alkaline batteries after removal of Hg. ► Almost total removal of Hg is achieved at low temperature in air. ► Nitrogen atmosphere is needed to reduce zinc ...and to permit its volatilization. ► A high grade Zn concentrate was obtained with a high recovery at 1000–1200°C. ► The grade of Mn in the residue was enhanced with complete recovery.
The aim of this paper is the recovery of manganese and zinc from a mixture of zinc–carbon and alkaline spent batteries, containing 40.9% of Mn and 30.1% of Zn, after preliminary physical treatment followed by removal of mercury. Separation of the metals has been carried out on the basis of their different boiling points, being 357°C and 906°C the boiling point of mercury and zinc and 1564°C the melting point of Mn2O3. Characterization by chemical analysis, TGA/DTA and X-ray powder diffraction of the mixture has been carried out after comminution sieving and shaking table treatment to remove the anodic collectors and most of chlorides contained in the mixture. The mixture has been roasted at various temperatures and resident times in a flow of air to set the best conditions to remove mercury that were 400°C and 10min. After that, the flow of air has been turned into a nitrogen one (inert atmosphere) and the temperatures raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture and recovered after volatilization as a high grade concentrate, while manganese was left in the residue. The recovery and the grade of the two metals, at 1000°C and 30min residence time, were 84% and 100% for zinc and 85% and 63% for manganese, respectively. The recovery of zinc increased to 99% with a grade of 97% at 1200°C and 30min residence time, while the recovery and grade of manganese were 86% and 87%, respectively, at that temperature. Moreover, the chlorinated compounds that could form by the combustion of the plastics contained in the spent batteries, are destroyed at the temperature required by the process.
► We characterized spent zinc–carbon and alkaline batteries. ► Location of Mn and Zn in the spent batteries was determined. ► Zn and Mn are intimately mixed in the cathode of the zinc–carbon ...batteries. ► Zn and Mn are separately present in the anode and in the cathode of spent alkaline batteries respectively.
The aim of this paper is to characterize spent zinc–carbon and alkaline batteries. Characterization is essential to any process devoted to recovering the valuable materials contained in the batteries. In particular, the status of zinc and manganese has been established to permit treating only the zinc and manganese-bearing components in a recovery process, thus using smaller equipments and reducing both the material to treat and the energy consumption. At present, in fact, industrial processes treat the spent batteries as a bulk, only performing a preliminary separation with physical methods followed by a pyro- or hydrometallurgical process to recover zinc and manganese. Characterization has been carried out by chemical analysis, TGA/DTA analysis, XRPD and SEM analysis after having dismantled the batteries into the single components. Zinc and manganese are well separated in alkaline batteries while in zinc–carbon batteries the two metals are mixed, thus rendering difficult a preliminary separation by picking up the components containing the two metals separately.
Four commercial enzyme preparations containing cell-wall degrading enzyme activities were tested for their ability to facilitate lycopene extraction from tomato paste. At 25°C, up to 75.6% of the ...lycopene present in the tomato product was extracted by a two-stage procedure that consisted of a preliminary 5 hour enzyme incubation followed by a 3 hour solvent (hexane or ethyl acetate) extraction. Increasing the duration of the enzymatic treatment to 12-18 h allowed the recovery of 85-90% of total lycopene. The highest extraction yields were achieved by using enzyme preparations with polygalacturonase and pectin methylesterase in addition to pectin lyase or cellulase activities.
Temperature-programmed reduction (TPR) has been used in this work to study the reduction of copper in CuOZnO catalysts with different
Cu
Zn
atomic ratios using H
2 as reducing agent. In all ...catalysts, CuO was completely reduced to metal. The influence exerted by ZnO on the reduction of copper was evaluated for a wide range of composition and a scale of reducibility was established. ZnO affects the hydrogen reduction of copper, CuOZnO samples showing a different behaviour with respect to the pure copper oxide. The reduction is always promoted and, in particular, catalysts with lower copper loading (Cu:Zn < 30:70 as atomic ratio) showed the highest reactivity and are characterised by the presence of two reducible copper species. Results of a kinetic analysis based on the TPR profiles confirmed the role played by ZnO as promoter of the copper oxide reduction. The effect of the preparation method on the catalyst reducibility was also verified and discussed in a specific case. H
2CO
2H
2 redox cycles were carried out on some representative samples which, after the first reduction in H
2, were reoxidised with CO
2 and then reduced again by H
2. These experiments revealed that a small percent of metal copper formed in the CuOZnO catalysts is oxidised by CO
2 regardless of the catalyst composition, whereas metal copper formed by reduction of pure CuO is not reoxidised at a detectable level. Furthermore, it was evidenced that the small fraction of copper reoxidised by CO
2 was extremely reactive, being reduced at temperatures much lower than those found for the reduction of the as-prepared catalysts. Both the TPR investigation and the H
2CO
2H
2 redox cycles clearly assessed the presence of a synergistic effect arising by the contact of CuO with the ZnO particles.
The electrochemical decolorization of the Reactive Violet 5 azo dye on a boron-doped diamond anode was used as a model process to test a novel definitive screening design (DSD). This method allows a ...dramatic reduction in the number of experiments needed to investigate those systems characterized by a large number of variables. In this study, the effect of nine quantitative parameters was investigated: initial dye concentration (60–120 mg L
−1
), current density (100–500 A m
−2
), NaCl concentration (5–20 mM), Na
2
SO
4
concentration (35–65 mM), pH (3–11), temperature (20–45 °C), inter-electrode distance (0.5–3.5 cm), stirring rate (250–750 rpm) and electrolysis time (2–8 min). Analysis of DSD data showed that four out of the nine factors (initial dye concentration, current density, pH and electrolysis time) were statistically significant. These factors were retained for process characterization using a subsequent central composite design. Overall, the number of experiments was reduced from over 500 to only 41, thus confirming the validity of the proposed approach as a time-saving and efficient method.
Aim:
To identify differences between sexes in the clinical profile, use of resources, management and outcome in a large population of ‘real world’ patients with heart failure (HF).
Methods:
A ...prospective cross‐sectional survey was conducted on 2127 consecutive patients (47% women) admitted with HF to 167 cardiology and 250 internal medicine departments between February 14 and 25, 2000.
Results:
Women were older, had a higher prevalence of atrial fibrillation, and more frequently a hypertensive or valvular aetiology. Females were admitted more frequently in Medical than in Cardiology Departments. The rate of invasive and non‐invasive procedures was lower in women than in men, slightly higher if managed by cardiologists. Women were less frequently prescribed ACE‐inhibitors, amiodarone, and spironolactone, and more frequently prescribed digoxin. In‐hospital mortality was similar, without difference between health‐care providers. A 6‐month follow‐up was performed in 56.4% of the cases in both setting, but less frequently in women. Event rates were similar with nearly half of patients re‐hospitalised at least once.
Conclusion:
The ‘real’ HF woman has generally a more severe disease; she is an old lady who is more frequently hospitalised in a medical unit, receives few diagnostic, and cardiovascular procedures and pharmacological therapy, has a relatively low probability of dying in hospital, but a high likelihood of requiring readmission.
The concentration of bergamot peel oils by pervaporation, with and without enzymatic pre-treatment, is studied. The influence of different PV membranes, industrial enzymes and operational parameters ...on the PV process are also investigated. GC-MS analyses are carried out to evaluate the recovery of the main aroma compounds such as linalool, linalyl acetate and limonene.
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