Search results for "Electrodialysi"
showing 10 items of 159 documents
Evaluating the Utilization of Innovative Electrochemical Methodologies for the Real Wastewater Treatment
2021
Novel solutions for closed-loop Reverse Electrodialysis: thermodynamic characterisation and perspective analysis
2019
Abstract Closed-loop Reverse Electrodialysis is a novel technology to directly convert low-grade heat into electricity. It consists of a reverse electrodialysis (RED) unit where electricity is produced exploiting the salinity gradient between two salt-water solutions, coupled with a regeneration unit where waste-heat is used to treat the solutions exiting from the RED unit and restore their initial composition. One of the most important advantages of closed-loop systems compared to the open systems is the possibility to select ad-hoc salt solutions to achieve high efficiencies. Therefore, the properties of the salt solutions are essential to assess the performance of the energy generation a…
On the modelling of an Acid/Base Flow Battery: An innovative electrical energy storage device based on pH and salinity gradients
2020
Abstract Electrical energy storage can enhance the efficiency in the use of fluctuating renewable sources, e.g. solar and wind energy. The Acid/Base Flow Battery is an innovative and sustainable process to store electrical energy in the form of pH and salinity gradients via electrodialytic reversible techniques. Two electromembrane processes are involved: Bipolar Membrane Electrodialysis during the charge phase and its opposite, Bipolar Membrane Reverse Electrodialysis, during the discharge phase. For the first time, the present work aims at predicting the performance of this energy storage device via the development of a dynamic mathematical model based on a multi-scale approach with distr…
On the modelling of an Acid/Base Flow battery: an innovative electrical energy storage device based on pH and salinity gradients
2019
The Acid/Base Flow Battery (AB-FB) is an innovative and sustainable way to store electric energy. It can theoretically guarantee an energy density of about 11 kWh/m3, which is higher than that provided by pumped hydropower, osmotic energy storage and compressed air. The AB-FB stores energy as pH and salinity gradients by employing a stack provided with (i) channels, hosting the solutions at difference pH and concentrations, separated by (ii) monopolar and bipolar ion exchange membranes. Two different membrane processes are involved: the Bipolar Membrane Electrodialysis (ED-BM) as charging step and its opposite, Bipolar Membrane Reverse Electrodialysis (RED-BM) as discharging step. The prese…
Surface water RO permeate remineralization through minerals recovery from brines
2022
Assisted-Reverse Electrodialysis (A-RED) technology was applied following reverse osmosis (RO) of a surface water resource in order to recover minerals from its brine and directly remineralize the RO unit's permeate. Four different sets of cation/anion exchange membranes were benchmarked using single- and mixed-salts synthetic solutions as well as real brine and permeate streams produced from three-stage reverse osmosis applied to Seine River water. The process, operating under equal permeate and brine channel flows (2 cm/s velocities) and applied voltage varying from 0 to 10 V, showed viable remineralization results. Optimal recovery at 10 V applied allowed increasing permeate mineral cont…
Reverse electrodialysis heat-engine: Case studies of improving energy efficiency through recovery of low temperature excess heat
2018
Reverse Electrodialysis (RED) is a technology for generating electricity from the difference in salinity between two solutions. RED is usually applied to natural water streams with different salinities, like seawater vs. freshwater. In the RED Heat-to-Power project we explore the option of using artificial water solutions operating in a closed loop where the difference in salinity is regenerated in a separation step powered by heat at temperature ranges between 60 and 100°C. We call this system Reverse Electrodialysis Heat Engine (RED HE). In this paper, first we summarise the possible system configurations and the overall amount of excess heat available in Europe for powering the RED HE pr…
Modelling the Reverse ElectroDialysis process with seawater and concentrated brines
2012
Technologies for the exploitation of renewable energies have been dramatically increasing in number, complexity and type of source adopted. Among the others, the use of saline gradient power is one of the latest emerging possibilities, related to the use of the osmotic/chemical potential energy of concentrated saline solutions. Nowadays, the fate of this renewable energy source is intrinsically linked to the development of the pressure retarded osmosis and reverse electrodialysis technologies. In the latter, the different concentrations of two saline solutions is used as a driving force for the direct production of electricity within a stack very similar to the conventional electrodialysis …
Investigation of electrode material – Redox couple systems for reverse electrodialysis processes. Part I: Iron redox couples
2012
Abstract The performances of electrodialysis (ED) and reverse electrodialysis (RED) processes depend on several factors, including the nature of the electrode material and of the redox couple adopted to make possible the conversion between electric power and chemical potential. In this paper, the possible 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 was studied by a detailed experimental investigation. The hexacyanoferrate(III)/hexacyanoferrate(II) system was stable for long time (more than 12 days) in the absence of light and oxygen at high redox couple concent…
CLOSING THE LOOP: STUDY OF INTEGRATED CYCLES WITH NATURAL AND ARTIFICIAL SOLUTIONS FOR THE PRODUCTION OF ENERGY, MINERALS AND FRESH WATER
Thermodynamic characterisation of novel solutions for closed-loop reverse electrodialysis
2018
Closed-loop reverse electrodialysis is a novel technology to convert low-grade heat directly into electricity. It consists of a reverse electrodialysis unit coupled with a regeneration unit in which the waste-heat is used to restore the initial conditions of the two solutions. One of the most impor- tant advantages of closed-loop system is the possibility to select an ad-hoc salt solution to obtain high efficiency. In this regard, it is important to assess how the salt solution properties affect the performance of the energy generation and solution regeneration processes. The aim of this study is to analyse the effect of thermodynamic properties of non-conventional salt solutions within a R…