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Hybrid Energy Systems for Water Industry
Published in Yatish T. Shah, Hybrid Energy Systems, 2021
On the other hand, energy production from salinity gradient can be a popular trend in the near future. Energy can be produced from a reverse electrodialysis (RED) due to the salinity gradient [174]. It is reported that the electrical potential of 0.1–0.2 V per pair of membrane can be produced from seawater and freshwater (or treated wastewater) through pairs of ion-exchange membranes in a RED. Globally, up to 980 GW of power could be generated from salinity gradient energy where freshwater flows into the sea [174]. A RED stack can be placed between the anode and cathode chambers of an MFC or microbial electrolysis cell, creating a hybrid technology called a microbial reverse electrodialysis cell (MRC).
The ocean as a source of renewable energy in sub-Saharan Africa: sources, potential, sustainability and challenges
Published in International Journal of Sustainable Energy, 2023
Alberto Filimão Sitoe, António Mubango Hoguane, Soufiane Haddout
Salinity gradient power is the energy created from the difference in salt concentration (Haddout et al. 2022; Helfer and Lemckert 2015; Schaetzle and Buisman 2015). It relies on osmotic pressure differences that occur in the interface between two water masses with different salinities (Schaetzle and Buisman 2015). The maximum potential of salinity gradient power is expected to occur in estuaries, where water from a river, with low salinity, meets the salt water of an ocean, with high salinity (Haddout et al. 2022; Jones and Finley 2003). Rough estimates indicate that in circumstances where water from the river has zero salinity and ocean water has salinity 35, energy equivalent to that of a 140−240 m high dam may be generated (Schaetzle and Buisman 2015). There are two main methods for harnessing salinity gradient energy. These are reverse electrodialysis (Govindarsu, JaiGanesh, and Kumaar 2020; Tristán et al. 2020; Tufa et al. 2020; Zoungrana and Çakmakci 2020) and pressure retarded osmosis (Altaee and Cipolina 2019; Chen et al. 2019; Ghaffour et al. 2019). Both processes rely on osmosis with membranes. The processes which generate electricity, however, yield brackish water as a by-product (Jalili et al. 2019; Zhu et al. 2017). The electricity produced can be used for many beneficial applications. Dubrawski et al. (2020) explored the use of the electricity generated to power a storm water disinfection plant.
Altering substrate properties of thin film nanocomposite membrane by Al2O3 nanoparticles for engineered osmosis process
Published in Environmental Technology, 2022
Zhen-Shen Liew, Yeek-Chia Ho, Woei Jye Lau, Nik Abdul Hadi Md Nordin, Soon-Onn Lai, Jun Ma
Power generation techniques currently available from osmotic power use membrane-based technologies such as PRO and reverse electrodialysis (RED) [3–5]. However, PRO displays greater efficiency and higher power density, and thus a better option to harvest power from high salinity gradient [5]. In a standard PRO process, water spontaneously permeates from the feed side to the pressurised high salinity draw solution side across the semi-permeable membrane. Consequently, the volume of diluted salt water volume and hydraulic pressure are increased which enable the generation of power by depressurising the solution through a hydro-turbine [6]. When a source of low salinity such as river water is available, seawater can serve as the high salinity source, and energy production can take place by mixing both streams through PRO process. This concept has been implemented by a Norwegian company – Statkraft in which they built a PRO demonstration plant with a power output between 2 and 4 kW.
Reviewing the recent developments of using graphene-based nanosized materials in membrane separations
Published in Critical Reviews in Environmental Science and Technology, 2022
Roberto Castro-Muñoz, Angélica Cruz-Cruz, Yrenka Alfaro-Sommers, Luisa Ximena Aranda-Jarillo, Emilia Gontarek-Castro
Ion-exchange membranes (IEMs) are used in various electrochemical devices, such as fuel cells, flow batteries, water electrolyzers, electrodialysis (ED), and reverse electrodialysis. IEMs implemented in ED are common in the desalination of seawater, brackish water, among other separation applications. Sulfonated poly(ether ether ketone) (SPK)/imidized graphene oxide (IGO) composite cation exchange membrane (CEM) had improved electrochemical and physicochemical properties, highly dependent on IGO content in the membrane matrix. The optimized SPK/IGO composite exhibited good water uptake (∼32.56%), ion-exchange capacity (∼2.16 meq·g−1), high permselectivity (∼0.87), with 6.1 mA cm−2 Ilim value, and conductivity (5.40 × 10−2 S cm−1) due to high molality of sulfonic acid groups. By operating in the desalination of brackish water (5000 ppm), the membrane exhibited 6.98 kWh kg−1 of salt removed energy consumption and 78.16% current efficiency (Shukla & Shahi, 2019). Using the same graphene material, mechanically robust and highly permselective anion exchange membranes (AEMs) were tailored based on GO and polybenzimidazolium nanocomposite. The excellent GO distribution contributed to great mechanical strength, high ion exchange capacity (between 1.7 and 2.1 mmol g−1), and more importantly, exceptional permselectivity (up to 0.99), and relatively low area resistance (lower than 2.9 Ω cm−2). Finally, the GO-based nanocomposite AEMs also demonstrated excellent potential for electrodialysis (Cseri et al., 2018).