Search results for "ion-exchange membrane"
showing 10 items of 20 documents
Simulation of bipolar membrane electrodialysis (BMED) units by a validated process model
2022
The BMED technology can be used for the production or the regeneration of acid and base solutions by water dissociation. BMED has practical applications in several fields including in chemical and biochemical industry, environmental protection and, recently, even for brine valorisation. Many are the irreversibility sources involved in the BMED process. Some of them are related to the non-ideal transport properties of the Ion Exchange Membranes causing undesired co-ion leakages and water flux. Furthermore, the presence of shunt currents through the manifolds (i.e. distributors and collectors of the solutions) decrease the current efficiency. The aim of this work is to give a quantitative des…
Design of a novel membrane-integrated waste acid recovery process from pickling solution
2019
Abstract Hydrochloric acid pickling is a common practice in steel manufacturing industry. During the process, acid is consumed to dissolve surface oxides and metals ions are accumulated in the solution, which becomes less effective with time. In addition, the costly and risky waste acid disposal is another issue affecting the hot-dip galvanizing industry. In this work, a novel sustainable waste acid recovery process from pickling solutions based on circular approach is proposed to tackle these issues. The innovative system allows (i) the continuous regeneration of pickling solutions to enhance process rate and performance and (ii) minimise the highly expensive and environmentally risky wast…
Electrodialysis with Bipolar Membranes for the Sustainable Production of Chemicals from Seawater Brines at Pilot Plant Scale
2023
Environmental concerns regarding the disposal of seawater reverse osmosis brines require the development of new valorization strategies. Electrodialysis with bipolar membrane (EDBM) technology enables the production of acid and base from a salty waste stream. In this study, an EDBM pilot plant with a membrane area of 19.2 m2 was tested. This total membrane area results much larger (i.e., more than 16 times larger) than those reported in the literature so far for the production of HCl and NaOH aqueous solutions, starting from NaCl brines. The pilot unit was tested both in continuous and discontinuous operation modes, at different current densities (200-500 A m-2). Particularly, three differe…
A comprehensive multi-scale process model of bipolar membrane electrodialysis (BMED) systems
Bipolar membrane electrodialysis (BMED) uses electrical energy to produce acidic and alkaline solutions by water dissociation. Its great versatility has increasingly gained the interest in chemical/biochemical industry and in environmental protection. Co-ion leakages through the membranes and shunt currents pose major issues leading to significant drops in current efficiency. This work focuses on the development of a novel model based on a multi-scale approach. Four different dimensional scales were fully integrated within a comprehensive simulating tool with distributed parameters. The lowest scale, which is represented by the channel, includes two sub-models. The CFD simulations sub-level…
REAPOWER – USE OF DESALINATION BRINE FOR POWER PRODUCTION THROUGH REVERSE ELECTRODIALYSIS
2015
Salinity gradient power (SGP) represents a viable renewable energy source associated with the mixing of two solutions of different salinities. Reverse electrodialysis (SGP-RE or RED) is a promising technology to exploit this energy source and directly generate electricity. However, although the principle of this technology is well known since several years, further R&D efforts are still necessary in order to explore the real potential of the SGP-RE process. With this regard, the aim of the REAPower project ( [GRAPHICS] ) is the development of an innovative system for power production by SGP-RE process, using sea (or brackish) water as a diluted solution and brine as a concentrate. The use o…
Bipolar membrane reverse electrodialysis for the sustainable recovery of energy from pH gradients of industrial wastewater: Performance prediction by…
2021
Abstract The theoretical energy density extractable from acidic and alkaline solutions is higher than 20 kWh m−3 of single solution when mixing 1 M concentrated streams. Therefore, acidic and alkaline industrial wastewater have a huge potential for the recovery of energy. To this purpose, bipolar membrane reverse electrodialysis (BMRED) is an interesting, yet poorly studied technology for the conversion of the mixing entropy of solutions at different pH into electricity. Although it shows promising performance, only few works have been presented in the literature so far, and no comprehensive models have been developed yet. This work presents a mathematical multi-scale model based on a semi-…
ELECTRICAL ENERGY STORAGE DEVICES BASED ON pH AND SALINITY GRADIENTS: MODELLING, EXPERIMENTS AND PILOTING
2021
Thermal potential of ion-exchange membranes and its application to thermoelectric power generation
2016
The low efficiency and high price of thermoelectric semiconductors has generated interest in unconventional forms of thermoelectric materials. In this article, ionic thermoelectricity has been studied with commercial ion-exchange membranes for different aqueous 1:1 electrolytes. The theory of thermal membrane potential has been derived taking into account the ionic heats of transport, the non-isothermal Donnan potentials, the temperature polarization, and the thermally-induced concentration polarization of the electrolyte. Also the generated thermoelectric power has been experimentally studied. The experiments show good agreement with the theory, and suggest ways for systematic improvement …
Energy harvesting by waste acid/base neutralization via bipolar membrane reverse electrodialysis
2020
Bipolar Membrane Reverse Electrodialysis (BMRED) can be used to produce electricity exploiting acid-base neutralization, thus representing a valuable route in reusing waste streams. The present work investigates the performance of a lab-scale BMRED module under several operating conditions. By feeding the stack with 1 M HCl and NaOH streams, a maximum power density of ~17 W m−2 was obtained at 100 A m−2 with a 10-triplet stack with a flow velocity of 1 cm s−1, while an energy density of ~10 kWh m−3 acid could be extracted by a complete neutralization. Parasitic currents along feed and drain manifolds significantly affected the performance of the stack when equipped with a higher number of t…
Electrostatic phenomena in ion exchange membranes
1971
Abstract Specific and transport properties of a cation and an anion exchange membrane in Na + and Cl - form respectively have been measured in water and dioxane water mixtures. A greater electrolyte absorption and a lesser specific conductivity and counterion transport number in solvents at higher dioxane content indicate strong electrostatic interactions between fixed groups in the membrane and counterions.