Özet:
In addition to being quantitatively limited, fossil fuel is negative to the earth by
inducing climate change. The energy transition is inevitable, and many alternatives
and renewable energy sources are being considered to replace fossil fuels.
Hydropower, wind and solar energy are leaders in the renewable energy world, but
huge and accessible other energy sources such as salinity gradient power (SGP) exist
and need to be collected to contribute to the energy demand. SGP is mainly extracted
with reverse electrodialysis (RED) and pressure retarded osmosis (PRO) systems.
A lab-scale RED module was constructed and used to monitor the energy generation
potential of different water bodies and the parameters associated with the
performance of the process. The optimal feed solutions concentration, flow rate and
their importance in improving the power density in RED were investigated and the
experimental results showed that increasing the flow rate is beneficial by
augmenting the power output of RED, but too high, it harms the process
performance. The results demonstrated that the voltage and the stack resistance
increased with increasing number of cell-pairs but the increasing trend of the
voltage decreased from the linear trend due to the stack resistance.
Lastly, the RED power output performance with treated different municipal
wastewaters was investigated together with natural seawater and synthetic
solutions. The synthetic solutions resulted in the highest power density. Among the
wastewaters, ultrafiltration (UF) effluent was more attractive for RED compared to
membrane bioreactor (MBR) and advanced biological treatment (ABT) effluents.
The SEM-EDX analysis showed that Mg2+ and Ca2+ were present in natural solutions
and may have contributed to reducing the power output. Although treated
municipal wastewaters discharged into seawater are important sources of RED-SGP,
feed solutions quality together with improved, highly selective and cost-effective ion
exchange membranes (IEMs) are necessary to optimize the power output.
