Fac-simile Scheda Linee di Ricerca - Federalimentare

Dati pubblicati inerenti il tema di ricerca:1. Fidaleo M., Moresi M. (2004) Optimal strategy to model the electrodialytic recovery of astrong electrolyte. J Membr Sc. 260, 90-111.In this work, mostly Nernst–Planck derived relationships were used to simulate the electrodialytic recovery of astrong electrolyte, namely sodium chloride. To this end, it was set up a five-step experimental procedure consistingof zero-current leaching, osmosis, and dialysis, electro-osmosis, desalination, current–voltage and validationtests. The contribution of leaching and solute diffusion across the electro-membranes was found to be negligiblewith respect to the electro-migration. On the contrary, solvent diffusion tended to be important as the solute concentrationdifference at the membrane sides increased or current density was reduced. The electro-osmosis anddesalination tests yielded the water and solute transport numbers.By performing several limiting current tests at different solute concentrations and feed flow rates using anionic orcationic membranes, it was possible to determine simultaneously the limiting current intensity, the ratio of the differencesbetween the counter-ion transport numbers in the anion- and cation-exchange membranes and solution,the overall resistance of the electro-membranes, the effective membrane surface area, and the solute mass transfercoefficient. All these process and design parameters allowed the time course of the solute concentration in theconcentrating (C) and diluting (D) compartments, as well as the voltage applied to the electrodes, to be reconstructedquite accurately without any further correction factors. The capability of the above parameters to simulatethe performance of the electrodialysis (ED) unit was checked by resorting to a few validation tests, that were performedin quite different operating conditions from those used in the training tests, that is by filling tank C with alow feed volume with a low solute concentration and applying a constant current intensity to magnify the effect ofelectro-osmosis or by changing the current intensity step-wisely to simulate the continuous-mode operation of amultistage ED unit. Finally, a parameter sensitivity analysis made the different contribution of the process and designparameters to be assessed, thus yielding a straightforward procedure for designing or optimising accuratelyED desalination units up to a final salt concentration of about 1.7 kmol m −3 .2. Fidaleo M., Moresi M. (2005) Modelling of Sodium Acetate Recovery from Aqueous solutionsby Electrodialysis. Biotechnol Bioeng 91: 556-568.The main engineering parameters (i.e., ion transport numbers in solution and electro-membranes; effective soluteand water transport numbers; effective membrane surface area, membrane surface resistances, and limiting currentintensity) affecting the recovery of sodium acetate from model solutions by electrodialysis (ED) were determinedin accordance with a sequential experimental procedure. Such parameters allowed a satisfactory simulationof a few validation tests carried out under constant or step-wisely variable current intensity. The performance ofthis ED process was characterized in terms of a current efficiency (Ω) of about 93% in the constant-current region,a water transport number (t W ) of about 15, and a specific energy consumption (ε) increasing from 0.14 to0.31 kWh/kg for a solute recovery yield of 95% as the current density (j) was increased from 112 to 337 A/m 2 .The specific resistance of the anion- or cation-exchange membranes were found to be three or two times greaterthan those measured in aqueous NaCI solutions and are to be used to design and/or optimize ED stacks involvedin the downstream processing of acetic acid fermentation broths.3. Fidaleo M., Moresi M. (2006) Electrodialysis applications in the food industry. Advances inFood and Nutrition Research, 51, 265-360.This paper reviews the most recent innovations in electrodialysis modules and/or processes that appear to affectthe food and drinks industries in the short-medium term, together with their basic mass transport equations thatmight help ED unit design or optimisation. Future perspectives for ED processing in the food sector are also outlined.SISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento di Scienze e Tecnologie Agroalimentari, Università degli Studi della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it484