Search results for "electrodialysi"
showing 10 items of 159 documents
1997
A bipolar membrane (BM) is a layered structure composed of one cation and one anion ion-exchange layers joined together in series. Polymer BMs offer promising applications for many industrial processes (e. g., the use of bipolar electrodialysis for environmentally clean technologies and the treatment of salt-water effluents) because of their unique electrochemical properties. The most important of these properties is the electric field enhanced (EFE) water dissociation which arises when an electric current is forced through the membrane. This phenomenon occurs at the bipolar junction of the BM, and its coupling with ion transport, though still poorly understood, is the basis of most of the …
Special applications of reverse electrodialysis
2016
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 incre…
Improving efficiency and discharge power of acid-base flow battery via a bi-objective optimisation
2023
Optimization of net power density in Reverse Electrodialysis
2019
Abstract Reverse Electrodialysis (RED) extracts electrical energy from the salinity difference between two solutions using selective ion exchange membranes. In RED, conditions yielding a large net power density (NPD) are generally desired, due to the still large cost of the membranes. NPD depends on a large number of physical and geometric parameters. Some of these, for example the inlet concentrations of concentrate and diluate, can be regarded as “scenario” variables, imposed by external constraints (e.g., availability) or chosen by different criteria than NPD maximization. Others, namely the thicknesses HCONC, HDIL and the velocities UCONC, UDIL in the concentrate and diluate channels, c…
The REAPower Project
2019
Abstract Reverse electrodialysis technology has grown significantly in the last decade, gaining a fast increase in its technology readiness level and presenting some interesting examples of pilot systems operating under very different real environments. Among these, one was able to operate in a saltwork in Marsala (Sicily, Italy) with real concentrated brine and real saline waters (i.e., either seawater or brackish water), producing electric power in the order of 1 kW. This pilot plant was one of the main achievements of the European REAPower research project. This chapter presents an overview of the main research efforts and results achieved in the framework of this project starting from t…
Cathodic abatement of Cr(VI) in water by microbial reverse-electrodialysis cells
2015
Abstract For the first time a microbial reverse electrodialysis cell (MRC) was used for the treatment of water contaminated by Cr(VI). It has been recently shown that both inorganic and organic pollutants can be removed by reverse electrodialysis processes (RED) using water with different salinity without the supply of electric energy. However, a high number of membrane pairs is usually necessary for the treatment of wastewater by RED. Here, it was showed that a lower number of membranes can be used by the utilization of a MRC (i.e., a RED cell with a biotic anode) for such purposes. Indeed, the abatement of Cr(VI), chosen as model pollutant, was successfully achieved by cathodic reduction …
CFD prediction of concentration polarization phenomena in spacer-filled channels for Reverse Electrodialysis
2014
Abstract Salinity Gradient Power generation through Reverse Electrodialysis (SGP-RE) is a promising technology to convert the chemical potential difference of a salinity gradient into electric energy. In SGP-RE systems, as in most membrane processes, concentration polarization phenomena may affect the theoretical driving force and thus the performance of the process. Operating conditions, including the feed solution flow rate and concentration and the channels׳ geometrical configuration, may greatly influence both the polarization effect and the pumping energy consumption. The present work uses CFD to investigate the dependence of concentration polarization and pressure drop on flow rate, f…
Modeling and Analysis of a New Process for Pyruvate Production
2005
Early process development is crucial for the economic and environmental performance of a final production process. A new process for the production of pyruvate is presented as a case study to show how process modeling and an analysis of the results regarding economic and environmental aspects improves the understanding of the process, its cost structure, and its environmental impact. It also enables the quantification of process improvements and the comparison of alternative designs. The model of the pyruvate production shows how strain and fermentation improvements propagate through the process and affect its economic and environmental performance. The comparison of two alternative purific…
SELECTION OF REDOX SYSTEMS FOR REVERSE ELECTRODIALYSIS PROCESSES
2012
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 co…