Alessandro Galia

ABSTRACT A new approach for the simultaneous generation of electric energy and the treatment of waters contaminated by recalcitrant pollutants using salinity gradients was proposed. Reverse electrodialysis allows for the generation of electric energy from salinity gradients. Indeed, the utilization of different salt concentrations gives a potential difference between the electrodes which allows the generation of electric energy by using suitable electrolytes and an external circuit. The simultaneous generation of electric energy and the treatment of waters contaminated by Cr(VI) was successfully achieved for the first time by reverse electrodialysis processes using salinity gradients and proper redox processes. The effect on the process of many operative parameters, such as the extent of the salinity gradient, the number of membrane pairs in the stack, the initial concentration of Cr(VI), the concentration of the supporting electrolyte and the flow rates of the solutions fed in the stack, was also investigated.

In reverse electrodialysis (RED) processes, electrical energy is directly extracted from chemical potential gradients arising from salinity differences, especially from sea and river water. In RED there are at least four complementary elements: (1) electrodes, where electron transfer reactions occur to allow the transformation of the charge carrier from ion to electron; (2) ion selective exchange membranes, which allow the selective transport of ions; (3) solvents, which make a continuum for ion transport; (4) electrolytes, i.e. the current carriers between cathode and anode. Studies on RED processes were mainly focused on membranes but also on several other aspects including electrolyte compositions and concentration, modeling and fluidodynamics. Less attention has been given to the selection of the electrodic material-redox couple system (for the purpose of this work defined electrode system) with very few exceptions , the most relevant being a very recent paper of Veerman and co-authors that carried out a very detailed comparative assessment of the suitability for RED of selected electrode systems described in literature [1]. On the other hand, the behavior of these systems was rarely experimentally investigated under operative conditions of interest for RED or electrodialysis (ED) applications. Electrode systems can be grouped in two categories: with or without opposite electrode reactions [1]. In the first case, when recirculation of electrode rinse solution is adopted, no net modification of the chemical composition occurs and the electrodic thermodynamic voltage is null. The opposite electrode reactions can involve reactive electrodes such as in the systems Cu-CuSO4 , Ag-AgCl, Zn-ZnCl2 or homogeneous redox couples with inert electrodes [1]. This work was devoted to the study of the utilization of iron based redox couples FeCl3/FeCl2, Hexacyanoferrate(III)/Hexacyanoferrate(II) and Fe(III)EDTA/Fe(II)EDTA on graphite and DSA electrodes for RED processes. To evaluate the advantages and disadvantages of these processes, numerous experiments were carried out in undivided and divided cells and in stack for the generation of energy. The Hexacyanoferrate(III)/Hexacyanoferrate(II) system was stable for long times in the absence of light and oxygen at high redox couple concentrations and low current densities both at compact graphite and DSA electrodes. Perfluorinated Nafion cationic membranes were found to be impermeable to the components of the redox couple. Fe(II)EDTA exhibited a limited electrochemical stability in long term electrolyses at all adopted operative conditions, that discourages the use of the Fe(III)EDTA/Fe(II)EDTA for RED applications. The system FeCl3/FeCl2 was, on the other hand, stable for long times at acidic pH at compact graphite electrodes. Selemion anionic membranes allowed to confine the redox couple in the electrode compartments with very slow passage of protons to the side compartment

In recent years the use of supercritical carbon dioxide (scCO2) in polymer processing and reaction has emerged as a \u201cgreen\u201d alternative to replace both environmentally hazardous organic solvents and water, whose utilization involves the production of large amount of waste streams. Moreover, scCO2 is non-toxic, inexpensive, and often exhibits intense plasticizing effect on polymers. In this work, the copolymerization of fluorinated monomers in scCO2 is explored. Batch free-radical copolymerization reactions of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) have been carried out at temperature of 50 C and pressure of 400 bar using DEPDC as initiator and different amounts of stabilizer (FLK-7004A). Conversion, composition, molecular weight and particle size have been measured by gravimetry, 19F-NMR, gel permeation chromatography and electron microscopy, thus providing a comprehensive characterization of the product. In the case of VDF precipitation homopolymerization in scCO2, bimodal MWDs have been reported. Two different hypotheses regarding the phase behavior of the system have been proposed to explain such eterogeneity, the first invokes chain-transfer to polymer in an homogeneous reaction system, the second mass transport limitations of the radicals between supercritical and polymer phase in an heterogeneous reaction system. The experimental data here presented support the second scenario; namely, monomodal high-MWDs are obtained carrying out the reaction under stable dispersion conditions, thus favoring the radical transport from the continuous to the dispersed phase by increasing the interfacial area. Accordingly, a mathematical model accounting for two reaction loci (continuous and dispersed phases) as well as the interphase transport of radicals, has been developed and validated by comparison with the experimental results. Even though some parameter fitting was required, the final model prediction ability is satisfactory, especially in terms of copolymer composition and molecular weight distribution. Such agreement is believed to represent an effective confirmation of the presumed two loci reaction mechanism

... carbocation and the counterion alone or associated to a suitable Lewis base to increase ... This effort must be coupled with a more thorough understanding of the phase behaviour ... these considerations it seems reasonable to foresee that the sector of polymerisation in supercritical ...

ABSTRACT A new approach for the simultaneous generation of electric energy and the treatment of waters contaminated by recalcitrant pollutants using salinity gradients was proposed. Reverse electrodialysis allows for the generation of electric energy from salinity gradients. Indeed, the utilization of different salt concentrations gives a potential difference between the electrodes which allows the generation of electric energy by using suitable electrolytes and an external circuit. The simultaneous generation of electric energy and the treatment of waters contaminated by Cr(VI) was successfully achieved for the first time by reverse electrodialysis processes using salinity gradients and proper redox processes. The effect on the process of many operative parameters, such as the extent of the salinity gradient, the number of membrane pairs in the stack, the initial concentration of Cr(VI), the concentration of the supporting electrolyte and the flow rates of the solutions fed in the stack, was also investigated.

In reverse electrodialysis (RED) processes, electrical energy is directly extracted from chemical potential gradients arising from salinity differences, especially from sea and river water. In RED there are at least four complementary elements: (1) electrodes, where electron transfer reactions occur to allow the transformation of the charge carrier from ion to electron; (2) ion selective exchange membranes, which allow the selective transport of ions; (3) solvents, which make a continuum for ion transport; (4) electrolytes, i.e. the current carriers between cathode and anode. Studies on RED processes were mainly focused on membranes but also on several other aspects including electrolyte compositions and concentration, modeling and fluidodynamics. Less attention has been given to the selection of the electrodic material-redox couple system (for the purpose of this work defined electrode system) with very few exceptions , the most relevant being a very recent paper of Veerman and co-authors that carried out a very detailed comparative assessment of the suitability for RED of selected electrode systems described in literature [1]. On the other hand, the behavior of these systems was rarely experimentally investigated under operative conditions of interest for RED or electrodialysis (ED) applications. Electrode systems can be grouped in two categories: with or without opposite electrode reactions [1]. In the first case, when recirculation of electrode rinse solution is adopted, no net modification of the chemical composition occurs and the electrodic thermodynamic voltage is null. The opposite electrode reactions can involve reactive electrodes such as in the systems Cu-CuSO4 , Ag-AgCl, Zn-ZnCl2 or homogeneous redox couples with inert electrodes [1]. This work was devoted to the study of the utilization of iron based redox couples FeCl3/FeCl2, Hexacyanoferrate(III)/Hexacyanoferrate(II) and Fe(III)EDTA/Fe(II)EDTA on graphite and DSA electrodes for RED processes. To evaluate the advantages and disadvantages of these processes, numerous experiments were carried out in undivided and divided cells and in stack for the generation of energy. The Hexacyanoferrate(III)/Hexacyanoferrate(II) system was stable for long times in the absence of light and oxygen at high redox couple concentrations and low current densities both at compact graphite and DSA electrodes. Perfluorinated Nafion cationic membranes were found to be impermeable to the components of the redox couple. Fe(II)EDTA exhibited a limited electrochemical stability in long term electrolyses at all adopted operative conditions, that discourages the use of the Fe(III)EDTA/Fe(II)EDTA for RED applications. The system FeCl3/FeCl2 was, on the other hand, stable for long times at acidic pH at compact graphite electrodes. Selemion anionic membranes allowed to confine the redox couple in the electrode compartments with very slow passage of protons to the side compartment

In recent years the use of supercritical carbon dioxide (scCO2) in polymer processing and reaction has emerged as a \u201cgreen\u201d alternative to replace both environmentally hazardous organic solvents and water, whose utilization involves the production of large amount of waste streams. Moreover, scCO2 is non-toxic, inexpensive, and often exhibits intense plasticizing effect on polymers. In this work, the copolymerization of fluorinated monomers in scCO2 is explored. Batch free-radical copolymerization reactions of vinylidene fluoride (VDF) and hexafluoropropylene (HFP) have been carried out at temperature of 50 C and pressure of 400 bar using DEPDC as initiator and different amounts of stabilizer (FLK-7004A). Conversion, composition, molecular weight and particle size have been measured by gravimetry, 19F-NMR, gel permeation chromatography and electron microscopy, thus providing a comprehensive characterization of the product. In the case of VDF precipitation homopolymerization in scCO2, bimodal MWDs have been reported. Two different hypotheses regarding the phase behavior of the system have been proposed to explain such eterogeneity, the first invokes chain-transfer to polymer in an homogeneous reaction system, the second mass transport limitations of the radicals between supercritical and polymer phase in an heterogeneous reaction system. The experimental data here presented support the second scenario; namely, monomodal high-MWDs are obtained carrying out the reaction under stable dispersion conditions, thus favoring the radical transport from the continuous to the dispersed phase by increasing the interfacial area. Accordingly, a mathematical model accounting for two reaction loci (continuous and dispersed phases) as well as the interphase transport of radicals, has been developed and validated by comparison with the experimental results. Even though some parameter fitting was required, the final model prediction ability is satisfactory, especially in terms of copolymer composition and molecular weight distribution. Such agreement is believed to represent an effective confirmation of the presumed two loci reaction mechanism

The electrocarboxylation of benzyl halides to the corresponding carboxylic acids through homogeneous charge-transfer catalysis was investigated both theoretically and experimentally to determine the influence of the operative parameters on the yield of the process and on the catalyst consumption. Theoretical considerations, based on fast kinetics of redox catalysis, were confirmed by the electrocarboxylation of 1-phenyl-1-chloroethane catalyzed by 1,3-benzenedicarboxylic acid dimethyl ester performed at a carbon cathode under different operative conditions. We obtained high yields of the target carboxylic acid and experienced a low catalyst consumption by operating with optimized [RX]bulk/[CO2]bulk and [RX]bulk/[catalyst] ratios.

... carbocation and the counterion alone or associated to a suitable Lewis base to increase ... This effort must be coupled with a more thorough understanding of the phase behaviour ... these considerations it seems reasonable to foresee that the sector of polymerisation in supercritical ...

The electrocarboxylation of benzyl halides to the corresponding carboxylic acids through homogeneous charge-transfer catalysis was investigated both theoretically and experimentally to determine the influence of the operative parameters on the yield of the process and on the catalyst consumption. Theoretical considerations, based on fast kinetics of redox catalysis, were confirmed by the electrocarboxylation of 1-phenyl-1-chloroethane catalyzed by 1,3-benzenedicarboxylic acid dimethyl ester performed at a carbon cathode under different operative conditions. We obtained high yields of the target carboxylic acid and experienced a low catalyst consumption by operating with optimized [RX]bulk/[CO2]bulk and [RX]bulk/[catalyst] ratios.

Reverse electrodialysis (RED) is a process for direct electricity production from salinity gradients, based on the use of suitable exchange membranes. To develop the RED process on an applicative scale and to add value to the overall process, a key role is entrusted to the selection of electrodic system, redox species, and electrode materials. In particular, it was shown that a proper selection of redox processes allows the use of a RED cell for the wastewater treatment of organic and inorganic pollutants resistant to conventional biological methods and for the synthesis of chemicals without energy supply. The utilization of microbial reverse electrodialysis cells was also proposed to increase the production of electric energy, coupled with the synthesis of chemicals or the treatment of wastewater.

To curb the severely rising levels of carbon dioxide in the atmosphere, new approaches to capture and utilize this greenhouse gas are currently being investigated. In the last few years, many researches have focused on the electrochemical conversion of CO2 to added-value products in aqueous electrolyte solutions. In this backdrop, the pressurized electroreduction of CO2 can be assumed an up-and-coming alternative process for the production of valuable organic chemicals [1-3]. In this work, the process was studied in an undivided cell with tin cathode in order to produce formic acid and develop a theoretical model, predicting the effect of several operative parameters. The model is based on the cathodic conversion of pressurized CO2 to HCOOH and it also accounts for its anodic oxidation. In particular, the electrochemical reduction of CO2 to formic acid was performed in pressurized filter press cell with a continuous recirculation of electrolytic solution (0.9 L) at a tin cathode (9 cm2) for a long time (charge passed 67\u2019000 C). It was shown that it is possible to scale-up the process by maintaining good results in terms of faradaic efficiency and generating significantly high concentrations of HCOOH (about 0.4 M) [4]. It was also demonstrated that, for pressurized systems, the process is under the mixed kinetic control of mass transfer of CO2 and the reduction of adsorbed CO2 (described by the Langmuir equation), following our proposed reaction mechanism [5]. Moreover, the theoretical model is in good agreement with the experimental results collected and well describes the effect of several operating parameters, including current density, pressure, and the type of reactor used. 1. Ma, S., & Kenis, P. J. (2013). Electrochemical conversion of CO2 to useful chemicals: current status, remaining challenges, and future opportunities. Current Opinion in Chemical Engineering, 2(2), 191-199. 2. Endr\u151di, B., Bencsik, G., Darvas, F., Jones, R., Rajeshwar, K., & Jan\ue1ky, C. (2017). Continuous-flow electroreduction of carbon dioxide. Progress in Energy and Combustion Science, 62, 133-154. 3. Dufek, E. J., Lister, T. E., Stone, S. G., & McIlwain, M. E. (2012). Operation of a pressurized system for continuous reduction of CO2. Journal of The Electrochemical Society, 159(9), F514-F517. 4. Proietto, F., Schiavo, B., Galia, A., & Scialdone, O. (2018). Electrochemical conversion of CO2 to HCOOH at tin cathode in a pressurized undivided filter-press cell. Electrochimica Acta, 277, 30-40. 5. Proietto, F., Galia, A., & Scialdone, O. (2019) Electrochemical conversion of CO2 to HCOOH at tin cathode: development of a theoretical model and comparison with experimental results. ChemElectroChem, 6, 162-172

Atom transfer radical polymerization (ATRP) is a versatile technique for exerting precise control over polymer molecular weights, molecular weight distributions, and complex architectures. It has been recently shown that an externally applied electrochemical potential can reversibly activate the copper catalyst for this process by a one-electron reduction of an initially added air-stable cubric species (Cu(II)/Ligand) [1-2]. In particular Gennaro and co-authors have shown that the polymerization kinetic can be changed modulating the external potential [1-2]. In the last years, an increasing interest has been devoted to synthesis of graft copolymers obtained from commercial polymers for incorporating specific properties into a material while retaining desiderable properties of the parent polymer. ATRP has been recently used to prepare graft copolymers from polymeric macroinitiators polymer chains with regularly spaced, pendant chemical groups containing radically transferable halogen atoms [3]. The halogen atom serve as initiation sites for the polymerization of side chains by ATRP. Our group has recently studied the atom transfer radical graft copolymerization by using halogen macroinitiators in organic and supercritical media [4]. As an extension of this work, also the electrochemically assisted atom transfer radical graft copolymerization has been studied by using various kinds of halogen macroinitiators such as poly(vinylidenefluoride) (PVDF) and poly(vinylchloride). Preliminary results will be presented in the meeting

A causa del progressivo impoverimento delle risorse di combustibili fossili e dell\u2019impatto negativo che il loro utilizzo ha sull'ambiente, la produzione di carburanti da fonti alternative, come le biomasse, ha ricevuto negli ultimi anni una notevole e crescente attenzione. Questo studio \ue8 incentrato sulla liquefazione idrotermica (HTL) dei fanghi provenienti dalla depurazione delle acque reflue civili. Tale tipo di biomassa oltre ad avere un alto tasso di umidit\ue0, ha un elevato contenuto organico e per essere smaltita \ue8 necessario che gli impianti di depurazione investano un ingente capitale [1]. L\u2019HTL tradizionale prevede l\u2019utilizzo dell\u2019acqua, in parte gi\ue0 contenuta nella biomassa, come solvente a temperature e pressioni nell'intervallo 250-400\ub0C e 10-30 MPa rispettivamente ed \ue8 considerato un approccio efficace per la conversione della biomassa in un bio-olio detto biocrude, il prodotto principale di riferimento, insieme con una fase acquosa, un solido residuo e una fase gassosa [1-2]. Tuttavia il biocrude prodotto dalla HTL in assenza di catalizzatori o co-solventi \ue8 molto viscoso e ha un alto contenuto di eteroatomi (S, N, O) indesiderati poich\ue9 ne abbassano la qualit\ue0 e ne impediscono l\u2019uso come combustibile per il trasporto. In particolare, un elevato contenuto di O riduce il potere calorifico ed aumenta la viscosit\ue0 del biocrude e un elevato contenuto di N e S porta alla formazione di NOx e SOx in atmosfera. Scopo del lavoro \ue8 studiare l\u2019effetto combinato dell\u2019acido formico, come co-solvente donatore di H2, e di un catalizzatore commerciale a base di CoMo/Al2O3 sulla resa e qualit\ue0 del biocrude prodotto con esperimenti di HTL di fanghi ottenuti da un impianto di depurazione di acque reflue. Diversi studi [3-4] hanno mostrato che elevate pressioni iniziali di H2 nel reattore di HTL causano un incremento del rapporto H/C dei biocrude prodotti sebbene non siano stati osservati effetti significativi sulle rese. Tuttavia ad oggi l'H2 \ue8 generato principalmente da fonti fossili e una delle maggiori sfide in questo contesto \ue8 la realizzazione di una possibile economia dell'idrogeno da fonti alternative. Inoltre dai risultati trovati in letteratura, \ue8 possibile dedurre che, in esperimenti di HTL di microalghe in reattori batch, l'uso di un mezzo di stoccaggio liquido di idrogeno come co-solvente produce effetti simili all\u2019idrogeno molecolare e permette di eliminare la resistenza al trasporto di massa dell\u2019H2 dalla fase gas alla miscela liquida. A partire da queste premesse \ue8 stato scelto come co-solvente l'acido formico (FA) poich\ue9 si decompone in idrogeno e anidride carbonica in condizioni miti di temperatura e pu\uf2 essere prodotto dalla riduzione elettrochimica del biossido di carbonio sfruttando energia verde e ne \ue8 stato studiato l\u2019effetto sulla resa e sulla qualit\ue0 del biocrude prodotto da HTL dei fanghi di depurazione

Wastewater treatment technology is undergoing a transformation due to more restrictive regulations governing the dischar ge and disposal of hazardous pollutants. Electrochemical based technologies are very promising methods for treating wastewaters containing organic and inorganic pollutants resistant to biological processes or toxic for microorganisms. These methods present numerous advantages including the utilisation of a green reagent such as the electron, very high removal of numerous recalcitrant pollutants, efficient disinfection, high flexibility and no necessity to transport or stock chemical oxidants or reducents. O n the other hand, a wide utilisation of such methods is likely to be limited by: (i) the cost of electric energy necessary to drive electrode reactions; (ii) the cost of the supporting electrolyte for waste waters with no adequate conductibility and (iii), for some applications, by the cost of electrodic materials. In order to overcome some of these drawbacks, some innovative solutions were proposed in the last years such as the utilization of micro reactors to avoid the utilization of supporting electrolyt es and to increase the current efficiencies for electrochemical processes controlled by mass transport stages such as direct oxidation processes or electro - Fenton (EF). To avoid the supply of electric energy to the system also the utilization of microbial fuel cells or reverse electrodialysis processes was proposed. Reverse electrodialysis is a clean, renewable energy with large global potential since the electricity is produced from supplies of water with different salt concentrations. In reverse electrod ialysis (RED), cation and anion conductive membranes are placed in an alternating way in order to produce dilute and concentrate compartments. The salt concentration difference (salt gradient) between both compartments in the cell pair creates a Nernst pot ential across the cell pair which causes an electrical current to flow through the electrical load connected to the electrodes. The electrochemical treatment of two different kinds of waste waters contaminated by Cr(VI) and a model dye, the Acid Orange 7 (AO7), respectively, driven by reverse electrodialysis processes was studied. It was shown that in both cases salinity gradients can be used to obtain electric energy and to successfully treat contaminated waste waters

It is widely accepted that one of the most important issue to be faced by the scientific community is how to sustain the modern way of living and the related energy demand. While a long term target is the transition to a full-renewable energy system, a closer exigency is the optimization of the processes already existing. It has been calculated that about 370.41 TWh of potential energy is annually lost in Europe in the form of waste-heat from the industrial sector [1]. Waste heat comprises all the thermal energy with a temperature below 130 \ub0C [2] (or 300 \ub0C [1]), that hardly can find a useful application with the state of the art industrial technologies. Indeed, electrochemical technologies are nowadays under investigation for the potentiality they own to harvest, at least, part of this energy [2]. Among the others, Thermally Regenerative Ammonia Batteries (TRAB) were reported to have very high current density and simple operation [3], but most of the work accomplished up to now was devoted to the optimization of the generation phase in conventional divided reactors. In this work, our efforts for the optimization of the regeneration phase are reported, along with a detailed exposure of the apparatus adopted. In addition, the use of an undivided continuous-flow, microfluidic reactor is proposed to sustain higher current densities with reduced investment cost. The effect of some relevant operative parameters on the maximum current density that can be gained in such a microfluidic device is also discussed

To minimize the negative effect of carbon dioxide as a greenhouse gas and introduce renewable energy in the chemical and energy chain, an interesting approach is the Carbon Capture and Conversion. In this context, one of more appealing conversion strategies is the el Ectrochemical reduction of CO2, which could combines the utilization of excess electric energy from intermittent renewable sources with CO2 (1). Furthermore, CO2 can be selectively converted into various useful chemicals by changing the operating conditions of electrolysis. In particular, an increasing attention has been devoted to the electrochemical conversion of carbon dioxide to carbon monoxide (2,3). The main obstacle of that conversion from water solution is the low CO2 solubility in water. In this work, a methodical study on the effect of the CO2 pressure and of other operating parameters on the conversion of CO2 at flat cathodes to carbon monoxide was performed. In detail, the reduction of CO2 was studied in different kind of electrochemical cells to evaluate the effect of various operating parameters, including the nature of the supporting electrolyte and the nature of cathode (Ag and Au), the current density, the pH and the pressure of CO2 . It was shown that an increase of the pressure leads to an improvement the stability of the electrode

It has been calculated that the energy dissipated wherever the rivers get to the sea this corresponds to an amount of about 2 TW of power [1]. Recovering part of this energy could attenuate the dependency of our economic system from fossil fuels. The techniques conceived to exploit this blue energy are grouped within the family of the salinity gradient technologies, where pressure-retarded osmosis (PRO) and reverse electrodialysis (RED) are regarded as the most established technologies [2]. Nevertheless, their power is limited respectively by various factors including the kinetics of electrodes reactions. Conversely, the use of capacitive electrodes proposed by Brogioli in 2009, does not seem to be affected from these limitations, relying only on ions movement across the electrical double layer [3]. The literature highlights that RED and capacitive electrode can take advantage of their combination, implementing the Capacitive RED (CRED) [4]. In this framework, different electrochemical techniques such as cyclic voltammetry, impedance spectroscopy and chronoamperometry can be used to characterize the performance of the electrodes. These different strategies are here compared and applied to the characterization of novel, super-critical-carbon-dioxide-prepared electrodes

Electrochemical methods can offer new sustainable routes for both the synthesis of chemicals and the abatement of organic pollutants resistant to biological processes. These methods use a clean reagent, the electron, and very mild operative conditions (ambient temperature and atmospheric pressure) with limited operative costs. However, electrochemical processes present some important disadvantages when performed in conventional reactors. In particular, to achieve reasonable cell voltages when the medium has not an adequate conductivity, one needs adding to the system a supporting electrolyte. This is certainly a main obstacle for a wide application of electrochemical tools. Indeed, adding chemicals is often a problematic issue, since this may lead to the formation of secondary products, makes more difficult the separation procedures and increases the operative costs. Recently it has been shown that the electrochemical processes can strongly benefit from the utilization of microfluidic electrochemical reactors (i.e. cells with a distance between the cathode and the anode of tens or hundreds of micrometers) allowing to minimize or even remove some of the above mentioned disadvantages. Thus, very small distances between electrodes lead from one side to a drastic reduction of the ohmic resistances, (allowing to operate with lower cell voltages and without supporting electrolyte), and on the other side to intensify the mass transport of the reagents towards electrodes surfaces. The utilization of micro devices may present the drawback of a more easy fouling but also other potential advantages such as an easier scale-up procedure through simple parallelization of many small units. Furthermore, since a very high conversion for passage can be achieved, the process can be performed under a continuous mode thus allowing a fast screening of the effect of operative parameters due to very short times of treatment. It would be also possible to operate with a series of micro cells with different applied current densities thus increasing both the current efficiency and the productivity of the cell [1-5]. In the present work some model processes of synthesis of fine chemicals and electrochemical abatement of pollutants were studied in microfluidic cells and in a stack with multiple cells in series with the aim of evaluating the advantages given by the utilization of microfluidic reactors

The common sterilization techniques are based on physical processes that involve, for example, the use of autoclaves or systems to radiation such as \u3b3-rays that can cause a structural change of the polymer treated. Therefore, the use of supercritical carbon dioxide (scCO2) is an excellent alternative, as it does not induce any variation of biomaterials treated (Perrut M., 2012). It's a good candidate because is readily available at low cost, non-toxic and non-flammable, it has an easily accessible critical point (7.38 MPa and 304.2 K) and excellent transport properties and wettability (White A. et al., 2005). We report the development of a supercritical CO2 based process capable of sterilization of PLLA [poly(L-lactic acid)] scaffolds that can be used for tissue engineering applications. The PLLA scaffolds were contaminated by the gram negative bacterium E. coli or environmental microorganisms: the amount of bacteria in each scaffold was determinated by colony-forming unit (CFU). Than they were subjected to different (for temperature or pressure values) supercritical CO2 processes. A good sterilization was obtain with a pressure of 150 bar for only 15 minutes of treatment at 37\ub0C. The process does not alter crystallinity and melting temperatures of the scaffolds, as demonstrated by DSC analysis (differential scanning calorimetry) of the scaffolds treated and not. Therefore, the treatment does not significantly alter the properties of the sample. The CO2 treatment does not intact the biocompatibility of the scaffolds as demonstrated by MTS assay (viability assay) of SK-HEP-1 tumour cells growth on the surface and the internal pores of the scaffolds. These results suggest that the scCO2 can be used as a perfect method of sterilization for PLLA scaffolds for their possible use for tissue engineering applications. \uf02d Michel Perrut, 2012 Sterilization and virus inactivation by supercritical fluids. The Journal of Supercritical Fluids. 66: 359-371. \uf02d White A. et al., 2006, Effective terminal sterilization using supercritical carbon dioxide. Journal of Biotechnology. 123(4):504-15