Salvatore Andini

Adsorption of chlorophenol, chloroaniline and methylene blue on fuel oil fly ash

Fuel oil fly ash has been tested as low-cost carbon-based adsorbent of 2-chlorophenol (CP), 2-chloroaniline (CA) and methylene blue (MB) from aqueous solutions. In all the cases the adsorption was found to be of cooperative type. Different adsorption capacities were found for the three organics. Specifically, it was highest for 2-chlorophenol, reaching about 70 mg g(-1), and quite lower in the other two cases, that is about 47 and 36 mg g(-1) for methylene blue and 2-chloroaniline, respectively. Varying the initial pH and adding KCl were found to have different effects on the adsorption of the three organics. In particular, the presence of other ions had no effect on the adsorption of methylene blue, adverse effect in the case of 2-chlorophenol and enhancing effect in the case of 2-chloroaniline.

NMR studies of prebiotic polypeptides

Several polypeptides prepared by means of pyrocondensation have been the subject of structural investigations. Attention has been focused on the constitutional characterization of homo-and co-polymers containing Asp and Glu residues, whose role is essential for the formation of the so-called proteinoids. Contrary to the literature data based on chemical degradation, nmr studies show conclusively that in thermal poly-aspartic acid only β-peptide linkages are present. This result casts serious doubt on the role thermal condensation might have played in prebiotic polypeptide syntheses.

Mechanochemistry of ibuprofen pharmaceutical.

In this paper mechanochemistry has been studied in view of possible application to detoxification of expired pharmaceuticals. The experiments have been carried out with a commercial medication containing ibuprofen ((RS)-2-(4-(2-methylpropyl)phenyl)propanoic acid) which has been submitted to prolonged milling up to 40h. When Al(OH)(3) is used as co-reagent, the first degradation step induced by the mechanochemical treatment is an acid-base reaction with the ibuprofen carboxylic acid group. The subsequent degradation follows a complex pathway leading to 1-(4-isobutylphenyl)ethanone, 1-isobutyl-4-vinylbenzene and 2-(4-(3-methylbutan-2-yl)phenyl)propan-1-ol after 10h milling and, in addition, 1-(4-acetylphenyl)-2-methylpropan-1-one, 1-(4-(1-hydroxy-2-methylpropyl)phenyl)ethanone and 1-(4-(2-hydroxy-2-methylpropyl)phenyl)ethanone after 40h milling. The degradation reaction path and products have been identified by means of FT-IR spectroscopy, thin layer chromatography, NMR spectroscopy, mass spectroscopy and elemental analysis. The observed ibuprofen decarboxylation makes the drug simultaneously lose both its pharmaceutical activity and toxicity.

Characterization of Geopolymer Materials Containing MSWI Fly Ash and Coal Fly Ash

In this work three samples of MSWI ash have been stabilized in systems containing coal fly ash and able to give geopolymers through a polycondensation reaction. Monolithic products were obtained with both MSWI ashes as received and after chloride partial removal by water washing. The polycondensation products have been characterized qualitatively by means of FT-IR spectroscopy and scanning electron microscopy (SEM) and quantitatively through the determination of the amount of reacted water and silicate. Differently from traditional cement based stabilization systems, those based on geopolymerization show a chemical behaviour almost insensitive to the presence of chlorides and sulphates in the MSWI ash. On the other hand, the microstructure is strongly affected by the content of soluble salts.

Clay sediment geopolymerization by means of alkali metal aluminate activation

In this work a clay sediment from a reservoir was employed for the synthesis of geopolymers. The sediment was calcined at 650 and 750 °C for 1 h to ensure the conversion of aluminium coordination from octahedral to tetrahedral. The sediment was characterized by means of X-ray fluorescence, X-ray diffraction, thermogravimetry, mercury intrusion porosimetry and scanning electron microscopy. After calcination, the sediment was submitted to X-ray diffraction, mercury intrusion porosimetry and scanning electron microscopy. Strongly alkaline sodium and potassium aluminate solutions were used to start the polycondensation reaction responsible for geopolymer formation. The initial alkali metal hydroxide concentrations of these solutions were 17, 15 (only Na), 13, 11 and 8.5 M. Polycondensation was carried out at 60 °C for times ranging from 15 min to 28 d. The geopolymer products obtained in all the experimental conditions tested were submitted to the quantitative determination of the extent of polycondensation through mass increase and loss on ignition, as well as to qualitative characterization by means of FT-IR spectroscopy. A reduced set of samples activated with solutions corresponding to initial [NaOH] 13 M and [KOH] 11 M and cured at 60 °C for 3 and 14 d were used for the determination of apparent density and unconfined compressive strength. These samples were also characterized by means of mercury intrusion porosimetry and scanning electron microscopy. The results have indicated that the development of preformed building materials starting from reservoir sediment, although requiring accurate mix design, can be possible by means of alkali metal aluminate activation.

Effect of Mechanochemical Processing on Adsorptive Properties of Blast Furnace Slag

AbstractMechanochemistry is of greater interest at present because of its application in the transformation of waste. In this study, an innovative application is proposed, namely to mechanochemically treat blast furnace slag so that it can be recycled into a low-cost adsorbent. In particular, the way this industrial waste adsorbs methylene blue present in aqueous solutions has been dealt with in detail. To this end, the slag was treated in a planetary mill at different charge ratios, rotational speeds and milling times, and then characterized by laser granulometry, porosimetric, X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses. These investigations shed light on the interrelationships between milling conditions and the physico-chemical characteristics of the slag. Next, the most interesting samples to submit to the following adsorption equilibrium and kinetic tests were chosen. These runs were conducted at different dye initial concentrations and adsorption times, and the results w...

New findings on soybean and methylester epoxidation with alumina as the catalyst

The activity of a commercial alumina, after a preliminary characterization, was investigated in epoxidation with soybean oil with aqueous hydrogen peroxide. Results show that the γ-alumina was an efficient catalyst. The role of the solvent in the epoxidation reaction in the presence of alumina was investigated. A “no-innocent” solvent role was demonstrated. Moreover, the optimization of the methyl oleate epoxidation reaction with alumina was eventually valuated, varying the type of the solvent and concentration of hydrogen peroxide in order to obtain a product with commercial features.

Comparative proton NMR studies of bovine semen and pancreas ribonucleases

The fine structure of bovine semen RNAase was studied with proton NMR spectroscopy making use of the four-protein system constituted by dimeric bovine semen RNAase, its catalytically active monomeric bis-(S-carboxymethyl-31,32) derivative, the naturally monomeric RNAase A from the pancrease of the same species, and dimerized RNAase A. Only four histidine C-2 H resonances were observed in the aromatic spectrum of bovine semen RNAase, which belong to the four histidine residues present in the sequence of bovine semen RNAase subunits at positions identical with those of the histidines of RNAase A. This is indicative of identical environments for the individual histidine residues in both subunits. These resonances were assigned (i) by comparing their titration curves with the corresponding curves obtained with RNAase A and with monomeric bovine semen RNAase and (ii) by evaluating the effects on their titration curves of nucleotide binding. Very similar NMR parameters were measured for His-105 and also for His-119 of seminal and pancreatic RNAase, while His-12 was found to have different environments in the two proteins. The distinctive NMR features of His-48 in bovine semen RNAase confirmed the role of the hinge regions of the subunits in maintaining the dimeric structure of the protein. While monomerization of the seminal enzyme reduced the differences between the histidine C-2 H resonances of RNAase A and bovine semen RNAase, dimerization of RNAase A did not affect the NMR spectrum of this protein, thus indicating as unlikely the possibility that the quaternary structure of bovine semen RNAase resembles that of dimerized RNAase A.