1,720,978 research outputs found
Studi Calorimetrici e Spettroscopici sul Polisaccaride Ionico Naturale Xanthan in Soluzione Acquosa
No full textPolyelectrolytic behaviour of ionic polysaccharides
No full textAn important aim of physico-chemical studies on natural and synthetic ionic-polysaccharides is to help elucidate the correlations between chemical structure-conformational characteristics of such polymers and their equilibrium properties in solution. In this context, attention is being given in our laboratory to the thermodynamics of macroion-counterion interactions and of polyion-polyion interactions, including [soluble] complex formation between polysaccharide macroions and different polyampholites (e.g. proteins) in dilute aqueous solution.
Our experimental approach is mainly based on the use of micro calorimetric, potentiometric, and chirooptical techniques. Polymers considered include: 1) sulfated polysaccharides (i-carrageenan, dextran sulfate); 2) glycosaminoglycans (heparins); 3) microbial polysaccharides (Xanthan, PS-10).
Species listed above (sodium salts) have been characterized in water and/or aqueous NaCl solution in terms of Na+ counterion activity coefficient, heat of dilution, and heat of Cu2+ ions binding. These experiments are part of a systematic investigation on the relationship between "charge-density" along polyelectrolyte chains and (metal) ion-binding, comparing experimenta
Dyes adsorption from aqueous solutions by Chitosan
Full text linkIn this study the ability of chitosan to remove acid, basic, reactive and direct dyestuffs by adsorption was studied. The effect of several factors influencing dye adsorption such as dye concentration, grain size, pH and temperature were investigated. Desorption of dyes at different pH was also examined. It was shown that the adsorption capacities of chitosan were comparatively high for acid and direct dyes and that the adsorption was controlled by the acidity of the solution. The kinetics of adsorption were found to be of pseudo second order. Batch isotherm studies showed that adsorption of dyes from aqueous solution by chitosan was described by the Langmuir equation
PROTONATION EQUILIBRIA OF THE POLYSACCHARIDE XANTHAN IN AQUEOUS-SOLUTION
No full text[no abstract available
CALORIMETRIC DATA ON SALT-INDUCED CONFORMATIONAL TRANSITIONS OF IONIC POLYSACCHARIDES IN AQUEOUS-SOLUTION
No full textReuse of residues arising from lead batteries recycle: a feasibility study
No full textThe performance of products arising from the stabilization/solidification of slags from lead batteries recycle into a Portland cement matrix has been evaluated not only in order to get a stabilized waste to be disposed of according to the current legislation, but also to obtain a recyclable material, with both economic and environmental benefits. Under this respect a detailed characterization of raw slags has been performed and different slag-cement samples have been prepared by varying the slag content. The parameters related to the cementation process have been evaluated and a series of tests on the final waste forms have been carried out, aimed at assessing both mechanical performance and leaching behaviour. In spite of the acceptable values for flexural, compressive and tensile strength, however, the high release of lead from the solidification products seems to be a limiting factor for a reusable material. While explanations of such phenomenon are given (high alkalinity of Portland cement; early "doping" of cementitious components by lead in the amorphous state), the main conclusion of the research work is that further efforts should be addressed to the adoption of a different or a modified incorporation matrix. (C) 2002 Elsevier Science Ltd. All rights reserved
Potenzialità autodepurative di una zona umida costiera e ipotesi di trattamento terziario dei reflui civili.
No full textApplying a field monitoring of parameters such as COD, BOD5 and NH3 and a plug & flow mathematical model, the water balance and the intrinsic nutrient abatement capacity was evaluated at Torre Flavia wetland. The strong water stress, mainly due to the large urbanization, can be avoided using the wetland as tertiary treatment of the wastewater treated at the Ladispoli treatment plant that actually discharge into the sea
Riutilizzo dei residui del processo di riciclaggio delle batterie al piombo: studio di fattibilità
No full text- …
